As the civil engineering industry undergoes a significant transformation, intelligent technologies have introduced novel technical means and tools for the innovation and advancement of structural health Monitoring （SHM） in civil engineering, thereby broadening the research scope in various aspects of SHM systems. This paper systematically sorts out and comprehensively reviews the current status of research on intelligent technologies applied in the field of SHM, covering areas such as computer vision, machine Learning, intelligent robots, and drones. Based on the review of existing research results, this paper looks forward to the development trends and prospects of intelligent technologies in the field of SHM, and deeply explores the innovations and challenges brought about by the integration of SHM and intelligent disciplines.

This paper presents main aspects of the structural design of Sichuan University Multi-Discipline Cross-Integration Platform and Art Education Center,including foundation,basement,structural arrangement,seismic fortification measures,structural analysis results and performance-based seismic design.The building characterizes complex shape,connected structure,large span and long cantilever.Critical issues of the structural design and methodology are presented with abovementioned characters. Analysis method and conclusions may be useful to similar projects.

Scientific and reasonable structural seismic damage assessment is of great significance for improving urban seismic resilience and smart operation and maintenance. Aiming at the actual needs and important problems in the construction of resilient cities at the present stage, and catering the latest paradigm of structural seismic damage assessment oriented to “global, dynamic and real-time”, allocating digital-based multi-model feature fusion and physical-based multi-level numerical simulations as two basic elements and relying on new techniques of deep learning, digital twin and knowledge fusion, a theoretical framework for near-real-time seismic damage assessment of structures based on digital-physical model hybrid interactive feedback is established. The main research content and key scientific issues in the framework are elaborated. The proposed theoretical framework is expected to improve the real-time and intelligence of structural seismic damage assessment, and help promote the construction of resilient cities and the smart operation and maintenance of urban systems.

With the continuous refinement of metallurgical technology in recent years, more and more high-strength structural steel has been emerging, its excellent physical and mechanical properties make it quickly applied to related projects. Similar to plain steel, the problem of fire resistance of high-strength steel structure is still very prominent. In the past ten years, the research on the fire resistance of high-strength steel has also started, and this paper makes a systematic investigation and summary on the high-strength steel fire-fighting high temperature and post-fire mechanics performance, high-strength steel components and node fire resistance, and high-strength steel structure fire resistance, and finally discusses and looks forward to the problem of under-research. At present, the research on the fire resistance performance of high-strength steel structure is still in the preliminary stage, and studies have shown that the high-temperature mechanics and fire resistance of high-strength steel have different degrees of deviation from the existing domestic and foreign relevant codes, and cannot be directly used.

Li Zijian Art Museum is a mega-steel-structure with mega-frames and braces.A ring atelier is supported by 17 main trusses suspended by 3 mega-columns.The main trusses are connected as a whole by an inside ring truss and an outside ring truss.The largest span along the ring atelier is 44.6 meters.Based on the performance-based design method,the performance objectives and design specifications of key components are proposed.Performances of the structure are verified under different levels,including elastic analysis under frequent earthquake,unyielding verification and elastic analyses under medium earthquake and elasto-plastic analysis under rare earthquake.The results show that a few plastic hinges formed in some braces and the first layer of the mega-columns.Good seismic behavior performed and seismic indices of key components can satisfy the predefined performance requirements.

Nondestructive testing technology of timber structure plays an important role in the preventive protection of ancient wood buildings and the intelligent operation and maintenance of modern timber structures. This paper classifies ten testing methods according to their basic principles, and introduces their application scope, research status and existing problems, including visual testing, stress wave, drilling resistance, and cutting-edge exploratory methods such as computer vision, piezoelectric sensing, Electromagnetic wave. Finally, the development trends of wood structure nondestructive testing are discussed.

With development of the construction industry,construction of large span steel structures in our country started extensively in our country.On the one hand,this promotes improvement of large span steel structural design,on the other hand, it also highlights some common design problems in the steel structures.This paper discusses basic steps for large span steel structural design and research.This study also discusses the design process of elastoplastic analysis in structural design and effect of structural form on ultimate bearing capacity,and summarizes frequently asked questions in the structural detail design about the selection of bearing types and the influence of the joint detail on mechanical properties of the structure.Finally,this paper presents design considerations and improvement measures to these common problems.

Taken a super high-rise frame-core wall structure as an example,comprehensive optimization of the original structural design calculation parameters,structural loads,walls,columns,beams,plates,roof steel structure brackets and raft foundation was conducted,where the structural stiffness,weight and cost were set as control objectives,while meeting the structural specifications and transfinite review requirements.Comparison of the stiffness,seismic performance and cost between the original design and the optimized one was conductedby PKPM software.The results show that all the indicators meet the specification requirements,and benefits such as reduced structural weight,reduced earthquake action, more reasonable stiffness distribution,increased ductility and structural safety,increased indoor space,shortened construction period and reduced construction cost of 22 million 946 thousand and 800 yuan profit.

The paper takes the tied arch bridge of steel tube truss arch rib as the research object. The combined stiffness of the arch rib is calculated by the combined column. Considering the triangular truss as the assembly in the rib surface,after the layout optimization, the corresponding combined effect coefficient is obtained, and the critical axis force of in-plane stability is determined by the interaction between arches and beams. For out-of-plane stability, the critical axis force is determined by the k-type truss as the longitudinal joint system.For the four-tube combination of the single arch rib arrangement, considering the non-directional load effect of the suspender tensile force offset,this arrangement provides the arch with the uprighting force to enhance the stability.Through an example,the practicality of the method described in this paper is demonstrated by the whole process of checking the stability of the concrete-filled steel tubular truss tied arch bridge with a main span of 120 m.

Combined with engineering examples, in the case of a single-storey garage and a two-storey garage respectively, the foundation form of raft and column pier and anti-uplift pile （reduced settlement pile） is adopted, and the number of anti-uplift piles is calculated according to the anti-floating requirements; under-column compensation piles, four piles under the column are used in this project to balance the settlement in two directions; the method of inverted beam and girder floor is used to verify the high water level anti-floating requirements of the foundation; the composite foundation method is used to verify that the water level is below the foundation; strive to achieve reasonable calculations for both anti-floating and compressive working conditions. This method is a relatively simplified algorithm, but it relies on the refinement of parameters such as soil coefficient of subgrade reaction, pile stiffness coefficient, and cap effect coefficient.

Offshore wind turbines bear more complex environmental loads than onshore wind turbines. It is essential for the design and safety operation of offshore wind turbines to reasonably assessment environmental loads. The method of wind and wave load calculation in offshore wind turbine specifications are roughly same, but there are differences in the selection of calculation parameters, which may make the calculation results of wind and wave load different. It is necessary to carry out comparative analysis on the calculation methods of wind and wave load in wind turbine specifications to explore the influence of different methods on the calculation of wind and wave load. This paper selects the latest specifications, including CCS specification, DNV GL specification and IEC specification to compare the differences of wind load and wave load calculation. Combined with typical examples, the comparative analysis is carried out. The results show that the maximum wind load of CCS and IEC is larger than that of DNV GL, and the consideration of wind turbulence is more conservative. For rough components, the peak wave load of DNV GL specification is about 4 %~14 % larger than that of CCS. According to the above analysis results, some suggestions are put forward for the selection of wind and wave load calculation methods and parameter selection of offshore wind turbines, which can be used for reference in the design of offshore wind turbines.

With the development of longer blade and higher tower,vibration problems of large-scale wind turbines operating continuously in harsh environment have become increasingly prominent, which brings great risks to the sustainable development of wind power industry.Under operation in generating electricity, the vibration of wind turbine has obvious aerodynamic damping and periodic components due to the spinning of the wheel.It thus becomes important to accurately obtain the dynamic characteristics of wind turbine under operation. In addition, due to the sources of uncertainty such as measurement errors, modeling errors, and data length,the precision of identified modal parameters results is also a key issue for the evaluation of safety performance.In this paper,operational modal analysis and uncertainty quantification is conducted using stochastic state-space model and maximum likelihood estimation considering harmonic components in measured vibrational data. The Expectation-Maximization （EM） algorithm for calculating the maximum likelihood and the Cramér-Rao Bound （CRB） bound for uncertainty quantification of modal parameters are adopted. With a large-scale wind turbine in service as a case study,the differences of modal parameters in different tower directions and the variations of modal parameters and their uncertainties of the wind turbine under different working conditions are analyzed and compared.

Deterioration of steel infrastructure due to service loads and environmental agents has been one of the major concerns in civil engineering community. Recently, iron based shape memory alloy （Fe-SMA） materials have been considered as an anlternative in retrofitting of aging steel structurs. Based on the shape memory effect, they can be conveniently used to apply prestress in comparison with traditional prstress techniques. This paper presents a state-of-art on fatigue strengthening of steel structures by using Fe-SMA materials, including the recovery stress of Fe-SMA materials, fatigue strengthening based on Fe-SMA materials, and effects of environmental temperatures and fatigue loading on the strengthening systems. The Fe-SMA retrofitting system is also compared with that by NiTinol-FRP hybrid materials.

The response displacement method is widely used for seismic design and analysis of underground structures,however,it has several shortages and limitations as a simplified method.Based on the basic principles of the response displacement method,a novel calculation method,named response shear stress method,is proposed with the soil-structure model in this paper.Both the soil-structure interaction and the shear stress distribution of soil layers can be easily and accurately incorporated into the proposed method.Because the uniform shearing interaction between the soil and structures is the principal reaction under seismic loadings,the seismic action can be assumed as the shearing force of soil layers,and then imposed on the soil-structure model.The seismic responses of the structure are finally obtained by the quasi-static method.The dynamic time-history analysis method is taken as the benchmark model to calibrate the proposed method.The optimum dimension of the soil-structure model used in the presented method is determined by comparison with the benchmark model.Furthermore,the validation of the proposed method is verified and approved to be applied for different geological conditions and structural section configurations.Results show that,the proposed response shear stress method could achieve consistent results with the benchmark model when the boundary dimension is over five times the structural diameter or height.Compared to the response displacement method,the response shear stress method could be widely applied in seismic analysis with different ground conditions and structure types.In addition,the design process of the proposed method is simpler and convenient,which provides a novel method for seismic design and analysis of underground structures.

Aspect ratio for tower transfinite structure can lead to insufficient capacity to resist capsizing and stiffness to resist lateral force, lack of tensile strength for wall limb.One can solve the problems by changing the structural plane arrangement,connecting the bottom of adjacent low and high towers to form an L-shaped combined tower at the bottom of the tower,and the equivalent resistance to the capsizing lever at the bottom of the structure can be increased.According to a number of plane and vertical irregular situations induced by the combined towers,corresponding seismic performance objectives are set up.Stress analysis on the floor weak parts and parts with contracted facade under frequent earthquakes was conducted. Stress analysis on the floor under medium earthquake static elasto-plastic pushover analysis and dynamic elasto-plastic time history analysis of the tower under rare earthquake were also conducted to study the nonlinear properties of the structure.The deformation mode,plasticity development and damage of the members as well as the elasto-plastic behaviors of the whole structure were investigated.According to the calculation results and the elasto-plastic behaviors of the structure, seismic performance of the structure was evaluated and instructions for the follow-up structural design were given.

The code for Seismic Design of Buildings （GB 50011—2010, 2016 edition） and the Technical Specification for Concrete Structures of Tall Buildings （JGJ 3—2010） both have provisions for performance-based seismic design, albeit with slight differences. Engineers, in their execution, may inevitably encounter confusion due to these variations. This paper analyzes the provisions of both codes regarding seismic performance design, and explains the meanings of seismic performance objectives and seismic performance levels from the perspective of load-displacement curves. It also compares the design parameters of the two codes. By listing 29 engineering cases adopting performance-based design methods, this study analyzed the basis for determining displacement indicators. Based on the analyses of these two aspects, the differences in the specifications regarding performance-based design are summarized, and design recommendations are provided.

In order to rationally design simply supported precast channel steel concrete composite beam for urban viaduct, structural design factors such as mid-span cross-beam layout, cross-section layout （number of main beams）, beam height, and bridge deck width were selected, and various parameters were set. The calculation and analysis of the determined composite girder bridge deck and steel girder slabs have resulted in the following conclusions： ① Under the premise of meeting the structural stress requirements, the installation of the mid-span beams will slightly increase the cost and affect the construction speed and landscape performance. Only the end beams can be installed; ② Generally, the arrangement of large openings and fewer beams is more cost-effective than the arrangement of small openings and multiple beams; ③ The economic beam height of the 30 m span composite beam is 1.6~1.8 m, the 35 m span economic beam height is 1.8~2.2 m, and the 40m span economic beam height is 2.0~2.4 m。

The self-drilling hollow grouting anchor is a new anchor incorporating functions of drilling, grouting and anchoring. Engineering issues such as collapse, shrinkage and unsaturated grout in soft and fractured rock can be solved effectively by application of such anchor in the underground anti-floating design. The paper carries out practical comparisons between the self-drilling hollow grouting anchor and fully grouted anchor in the fracture zone and non-fracture zone respectively for anti-floating applications. In the fracture zone, the two anchors are comprehensively analysed regarding anti-floating capacity, deformation characteristics, grouting pressure and grout amount. The test results show that the maximum pullout force of the self-drilling hollow grouting anchors is 400 kN, much larger than that of fully grouted anchors with a range of 310 kN-328 kN; the maximum deformation is 3.6 mm and residual deformation is 2.5 mm, much less than 7.6 mm and 5.7 mm of fully grouted anchors. The grouting pressure of hollow anchor and fully grouted anchor are 1.3 MPa and 1.0 MPa respectively, while the grout amount of the former is 20% higher than that of the latter. Therefore the anchorage behavior, grouting effects and durability of self-drilling hollow grouting anchor are evidently superior to those of fully grouted anchor. In addition, the self-drilling hollow grouting anchor becomes tensile prestress-typed after applying prestress.

Combined with the actual project,use SAP2000 finite element software to establish a 5×5 span underground garage structure model without beams, comprehensively consider factors such as the thickness of the soil, the type of construction vehicles and the parallel situation,and determine the unfavorable layout of construction vehicles according to the principle of influence lines,and obtain construction vehicles,etc. The effect of uniformly distributed load is compared with the commonly used construction load of 5 kN/m² in the design.The results show that the equivalent uniform load of construction vehicles is mostly greater than 5 kN/m²,and the equivalent uniform load value of construction vehicles decreases with the increase of the cover soil thickness,and increases with the increase of the vehicle load.Comprehensively considering the equivalent uniformly distributed loads of the four construction vehicles,the recommended values for the equivalent uniformly distributed loads of the construction vehicles are put forward, and the results can be used as reference for engineering design.

In civil engineering, steel or concrete beams need to be reinforced to increase its load-bearing capacity and service life due to damage, aging and bearing capacity degradation under service conditions. At present, the application of Fe-based shape memory alloys （Fe-SMA） to reinforce the structure has been proved to be an efficient and reliable method. This article reviews the shape memory properties, activation recovery properties and basic mechanical properties of Fe-SMA. And the principle of thermal excitation for structural reinforcement using Fe-SMA is described. On this basis, the connection methods between Fe-SMA members and the reinforced structure are reviewed from the aspects of reinforcing steel beams and concrete beams, and the existing research and applications are classified, analyzed and summarized according to the needs and purposes of reinforcement. Finally, in view of the shortcomings of the current research and application, this paper puts forward the perspectives that need to be researched, in order to promote the reasonable application of Fe-SMA in the field of civil engineering.

At present, there are various types of external thermal insulation composite systems （ETICS）used in China and the corresponding anti-peeling design method needs to be improved. Further studies are also needed on the insufficient interlayer bonding strength and the detailing defects, deterioration mechanism, identification and evaluation of falling-off of ETICS. Focusing on the complexity of pealing mechanism and difficulties on evaluating deterioration and identifying falling-off risk, this research summarized the main detailing systems, anti-peeling design method and defect types. The deterioration mechanism was discussed. The research status of falling-off risk identification and repairing method of ETICS was also analyzed.

On Dec.22,2021, an earthquake with magnitude of 4.2 occurred in Changzhou, Jiangsu Province, which is sensible in Shanghai. The field-structure seismological array,which is recently established at different campuses of Tongji University, got the efficient acceleration signal of this earthquake. The peak ground and building acceleration of five stations are in the range of 1-5 cm/s² and 1-6 cm/s² respectively. By comparative analysis of the field and building signal in time and frequency domain, the peak ground acceleration, response spectrum of ground signal along with the dynamic characteristic of the building signal were studied. The influence of the earthquake on Shanghai is relative sensible to low buildings of short natural period. Rapid intensity assessment by field and structure signal is discussed and the intensity of different campus is 1 to 3.

At present, there are few experimental studies on the shear behavior of H-beam recycled aggregate concrete slab composite beams. The shear performance of five full-scale specimens of H-beam recycled aggregate concrete slab composite beams is tested. The size of each specimen is the same. The clear span is 3 000 mm, the model of H-shaped steel is HN200×200×6×6, the width of recycled aggregate concrete slab is 300 mm and the thickness is 100 mm. H-shaped steel and recycled aggregate concrete slab are connected by studs. The replacement rate of recycled coarse aggregate （RCA） is 0%, 50% and 100% respectively, and the design strength grade of concrete is C30 and C60 respectively. The shear performance of the specimens with different design parameters are compared and discussed, and the influence of design parameters on the shear performance of the specimens is analyzed. The results show that the structure of the composite beam with stud connection is reliable, and the H-shaped steel and recycled aggregate concrete slab have good joint performance. The shear performance and failure mode of composite beams with different replacement ratio of RCA are similar. The stiffness, shear capacity and deformability of specimens with high strength are improved.

The deviated pre-tensioned girder with discounted reinforcement avoids the shortcomings of post-tensioned prestressed concrete girder in tunnel construction technology and durability, and improves the mechanical adaptability of prestressed concrete structure, so it has a broad application prospect in bridge engineering. In practical engineering, the concept of load transverse distribution coefficient is often used to simplify the spatial multi-beam system into single beam system for analysis and calculation. However, with the increase of span, bridge width and the adjustment of beam spacing, this simplified calculation method will have a significant impact on the spatial stress state of the actual structure. Therefore, this article established the three-dimensional finite element model of I-beam, this paper studies force behavior of I-beam, through comparing all kinds of load transverse distribution coefficient calculation method and the error of the actual space force, put forward the reasonable and applicable method by studying the transverse beam spacing on force of main girder space, put forward reasonable design reference.

In recent years, with the development of building industrialization, precast concrete shear wall has been widely used. To reduce the wet operation in the construction process and ensure the connection joint quality of precast concrete shear walls, a new bolted connection method for the precast concrete shear wall is proposed. In the core area of the shear wall, edge component, the design of the bolt number is based on the principle of equal strength replacement, the tensile strength of the bolt is much higher than the original steel bars. Then, according to the current national concrete design code, the bearing capacity of the bolt connected shear wall is calculated and compared with the finite element simulation results. It shows that The calculated value of normal section bearing capacity is consistent with the finite element simulation results; Through the calculation of shear capacity, it is concluded that the shear failure occurs in the wall with a low shear span ratio, which is compared with the damage cloud chart of concrete. The calculation of the shear capacity of the horizontal joint shows that the bolt connection has a great safety reserve in the horizontal direction, and there is no horizontal slip in the loading process.

In order to study the performance of complex joints of an transfinite steel structure building under rare earthquake, the finite element software ABAQUS was used to simulate the stress and destruction effect under ultimate load of key joints of transfer truss. The results show that： the Mises stress in other areas of the joint is significantly lower than the yield strength of the material, except that the local contact angle of each component reaches the yield strength and enters into plasticity. The whole joint basically keeps elastic state without obvious plastic development, which meets the performance target under rare earthquake. When the ultimate destruction occurs, the component area is destroyed prior to the node area, and the design of each joint meets the requirements of safety reserve. It can be seen that in the joint design of this project, the joint diaphragm and stiffening steel frame are taken as the main load transfer components, and the equivalent area principle is adopted to ensure that the bearing capacity of the joint is greater than the sum of the bearing capacity of each member entering the joint, and the structural design requirements of strong joint and weak member are ensured.

The base isolated structure of a multi-tower building with unified base-floor is analyzed and designed by YJK. The analysis results show that the base isolated structure can significantly reduce the earthquake action of the upper structure. With bearings and dampers reasonably used in the design, the torsion caused by the irregular structure plane can be reduced. Base isolation of multi-tower building is very suitable for use in high intensity areas. The main structure of the project has been basically completed. This paper can be used as a reference for the design of similar projects.

For 15 MW high-power wind turbine, a composite wind power tower structure with double-layer steel shell filled with concrete is proposed. In order to clarify the rationality of the wind power tower design, the mechanical properties of the composite tower and the steel tower are compared through solid-shell finite element analysis and theoretical calculation. The results show that compared with the large-diameter steel tower, the composite tower designed according to the equivalent bending capacity of cross-section can reduce the outer diameter of the tower by about 15%, and the maximum steel tower wall thickness by about 50%. The composite tower provides lateral restraint for the steel tower wall and avoids local buckling of the steel tower, which increases the compressive capacity of the composite tower section by about 30%-45%. The composite tower improves the section bending modulus and reduces the maximum live load bending stress of the steel tower wall by about 13%, which is conducive to reducing the wind load fatigue effect. The combination of double-layer steel shell and concrete can improve the mechanical performance of wind power tower, reduce the difficulty of processing and hoisting, and save the amount of steel. This paper can be used as a reference for the design of high-power wind power towers.

Deterioration of steel infrastructure due to service loads and environmental agents has been one of major concerns in civil engineering community. Carbon fiber-reinforced polymer （CFRP） materials have high strength-to-weight ratio, good resistance to fatigue and corrosion, and ease of installation. They are showing great promise in rehabilitation and strengthening of aging steel structures. In external bonding systems, the interfacial performance between CFRP and steel plays an important role to ensure the retrofitting efficiency. This paper presents a state-of-art on the CFRP-steel bond behavior when subjected to fatigue loading. Experimental scenarios, failure modes, bond strength, load-displacement curves, and bond-slip relationships from literature review are summarized and compared.

To study the influence of stud height and stud spacing on the shear behavior of short headed studs in ultra-high performance concrete （UHPC） composite deck, the connection project of Xihong Bridge was taken as the engineering background and push-out test and FEM parametric analysis were conducted. The push-out test revealed that the failure mode of short stud in UHPC was shear failure at the root of stud, and there was only partial crush in UHPC. The push-out test also found that there was a significant difference between the tensile and bending stress ratios of the upper and lower rows of studs along the load direction. According to the FEM analysis, shear rigidity tends to increase with the decrease of stud height when the stud height of 13 mm diameter stud ranges from 15 mm to 50 mm. When stud height decreases, stud will be pulled out and the crush area of UHPC will become larger. However, stud height has little impact on shear capacity of short headed stud. On the other side, stud spacing does not have significant influence on shear performance of short studs when changing in the range from 150 mm to 300 mm.

Recent years, modular steel construction has become a new type of prefabricated building system which is increasingly promoted by the state with its advantages including high efficiency and environmental protection in construction. Scholars at home and abroad have done numurous research on the mechanical property of modular steel construction. This paper systematically summarizes the application and research of modular steel construction in recent years from the aspects of inter-module connection, lateral force resisting system of the module, mechanical property of the group column, overall structure analysis, etc. The further research direction and development trend in this field are given combined with the existing relevant regulations and standards of modular steel construction, which will provide useful references for engineering practice and scientific research.

Based on the Shanghai Urban Renewal Regulations and the Medium and Long-term Development Plan of Shanghai Engineering Construction Standards （2021—2025）, this paper introduces system engineering methodology for multi-dimensional analysis through research on the current situation and development trend of relevant standards systems and special technologies at home and abroad, composes and summarizes the visionary objectives, scope boundaries and guiding principles for the preparation of the table of technical standards for the renovation of existing buildings. The draft of Shanghai Existing Building Renovation Technical Standard System Table was developed, and the suggestions for the improvement of Shanghai existing building renovation standard system by 2025 were proposed.

The project in the case is China's first monolithic precast concrete frame-corewall structure. The project is an AAA prefabricated building and a three-star green building. Through a pre-planning of prefabricated structural system selection and prefabricated scheme, combined with design, production,transportation and hoisting conditions, the structural design and splitting of prefabricated enclosure walls, fabricated floors,prefabricated core tubes and prefabricated concrete columns are planned.The logic of each planning is elaborated and the application of precast corewall technology is explored to provide a reference for the planning,structural design and splitting of similar prefabricated office buildings.It lays a foundation for the successful construction and standardized design of such projects,and promotes the development of concrete assembly technologies in the industrialization of new buildings in China.

The research is carried out on the ultra-deep pit of Qingxiushan Station with excavation depth of 58.7 m, taking the construction of rail transit pit in semi-diagenetic strata area of Nanning as the background. Through theoretical analysis, field monitoring data and numerical simulation, the influencing factors of deformation and mechanical characteristics are systematically analyzed. The formation mechanism and main influencing factors of double-peak or even multi-peak deformation mode of ultra-deep foundation pit retaining structure in semi-diagenetic strata are revealed. The calculation method of lateral pressure of semi-diagenetic strata is proposed. Reasonable earth pressure calculation methods and structural calculation models for ultra-deep foundation pits are given, of which the practicability is verified.

In order to improve the speed and efficiency of assembly building engineering design, the problems of single type of prefabricated slab creation, complex separation and not satisfying the needs of industrial production can be solved. Based on BIM technology, the intelligent application of prefabricated slab is realized under the development environment of Revit API and C# programming language. The main development functions include intelligent creation and split of prefabricated slab. The results show that compared with the traditional precast slab creation and split, this program can make designers set up the parameters of the creation and split of the precast slab, export the required prefabricated components quickly and efficiently, and greatly improve the design efficiency. It provides reference for the development of other prefabricated components in the intelligent direction, and has a wide application scenario.

The structure systems and existing problems of traditional rural residence in China are summarized,several precast housing systems which are suitable for the new rural construction are enumerated,the factors that prevent the development of rural precast house and the reasons for increased cost of it are analyzed.Through the investigation of the current situation about rural housing in Guanzhong area of Shaanxi province and the demand for housing construction of farmers,some suggestions about precast building in the construction of rural residence are presented,which provide a reference for the construction of new rural in china.

To study the influence of stiffness ratio on the performance of buckling-restrained brace-concrete frame structural systems and its likely reasonable value range, three concrete frames with different initial storey drifts are designed and analyzed respectively. By means of dynamic time history analysis of frequent earthquakes and rare earthquakes, the influences of different stiffness ratios on seismic performance of the frame structure, such as the inter-storey drift angle, inter-storey shear force, hysteretic energy dissipation ratio of bracing, plastic damage distribution, etc. Based on the analysis results, the likely suitable stiffness ratios are proposed for structures with different initial drift angles.

Based on the theory of elastic mechanics and corrosion mechanism of reinforcing steel, the critical corrosion amount of reinforcing steel for cracking of concrete cover was derived. Based on Faraday’s law, an analytical model for time to corrosion-induced cover cracking in reinforced concrete structures was established. The proposed analytical model was verified by comparing the analytical predictions with the experimental results. The main factors affecting the time to corrosion-induced cracking were analyzed. The analytical results show that the time to corrosion-induced cracking increases gradually with the increase of thickness of concrete cover thickness and elastic modulus. The time to corrosion-induced cracking decreases gradually with the increase in the volume expansion ratio of corrosion products, corrosion rate and tensile strength of concrete.

Environmental change has a direct impact on the ancient brick masonry.Taking the ancient bricks in Shanxi Province as an example to perform the laboratory test in investigating the compression damage of the bricks under freeze-thaw cycles in atmospheric environmental.The regulations of the cracks were analyzed using image processing techniques.The influences of the number in freeze-thaw cycles on compression features of the ancient brick masonry were furthermore examined.It shows that the width of cracks in the central part is less than that in other locations ;the crack load and failure load are larger than others as the number in freeze-thaw cycles reach to 20;when difference value between cracking load and failure load is larger than 190 kN,average of crack width is around 1.8 mm.The damages of the brick masonry in the first stage occur ahead of time significantly if the masonry beards the freeze-thaw cycles,and the damage percentage in the first stage is 35.16%,respectively.The results in the current study may be referable in analyzing the features on ancient brick masonry.

The slotting treatment after bellows are blocked in the prestressed construction process of long-span bridges will greatly weaken the bridge panel section and affect the bearing capacity and service performance of the structure. This paper studies the reinforcement treatment of large span bridge after the bellow is clogged, and puts forward the reinforcement scheme of adding prestressed tendons on the top surface of the original bridge panel and replacing the cushion layer on the original roof with new reinforced concrete composite layer. With this reinforcement method, the calculation results show that the total thickness of the bridge deck and the load on the bridge deck do not increase. In addition, the re-stretched original prestressed tendons and supplementary prestressed tendons together ensure the crack resistance of the structure. The thickness of the structural layer of the bridge deck increases, which ensures and improves the load-bearing capacity of the structure. It can provide reference for the reinforcement treatment of the same type of engineering.

Chinese construction industry has made remarkable achievements in technological progress and engineering practice. The comprehensive strength of construction enterprises has been continuously enhanced, with leading technological advantages and engineering practice in many aspects. A relatively perfect national engineering construction standard system has also been established in China. This paper studies the current engineering construction standards in the field of high-rise buildings in China, and establishes the Hall three-dimensional model of the design and construction technical standards. Through typical case studies of structural seismic design in high-intensity areas and super-thick raft foundation construction in desert areas, the highlights and experience have been analyzed for the application of Chinese high-rise building design and construction standards in international contract projects, and the significant impact of the selection of the standard system has been explored on project quality, construction organization, project progress and cost. It is indicated that China has accumulated rich experience in high-rise building design and construction in project planning and management, design optimization, building material development, construction technology improvement and innovation. The adoption of China's engineering construction standards is beneficial to improving the performance of Chinese enterprises in overseas projects and promoting the high-quality development of Chinese foreign contracting business.

The assessment of post-earthquake damage and seismic performance level of buildings is key process of performance-based seismic design. To solve the problem of the lack of an evaluation indicator for the earthquake-induced damage of double skin composite shear walls （DSCWs）, an experimental database including 37 flexural composite wall specimens under hysteretic loading tests is made in this paper. Based on the existing modified two-parameter Park-Ang damage assessment model, the empirical expression of the combination coefficient β about the design parameters （axial compression ratio, shear span ratio, section length-width ratio, steel content ratio, etc.） of the DSCW is established. Based on the seismic design concept in Chinese code that three-level performance target and two-stage seismic design, the damage states of the DSCWs can be divided into four levels： basically intact, slightly or moderately damaged, severely damaged, and failure, according to the feature points of the skeleton curves. The critical values of the corresponding damage indices are 0.086, 0.517, and 1.020, respectively. The research results of this paper can provide a necessary basis for the earthquake-induced damage evaluation, performance-based seismic design, and post-earthquake reinforcement of the DSCW structures.

Concerning the orthotropic steel bridge decks under above-deck explosions, a numerical simulation study based on steel plate explosion tests was conducted. The damage mechanism of the steel bridge deck of Taizhou Yangtze River Bridge was analyzed under explosions of five threat types specified by the Federal Emergency Management Agency （FEMA）, and the damage modes of different components of the bridge deck were revealed. The main conclusions are as follows. In all explosion scenarios, petal-shaped openings on the top plate, fracture and tearing of U-ribs, and plastic deformation of cross beams were observed. For scenarios with larger explosive charge （1 814 kg TNT, 4 536 kg TNT, and 13 608 kg TNT）, the failure modes of the bridge deck also include outward bending, local buckling, and fracture of cross beams, fracture of the U-ribs, and openings on the bottom plate. In scenarios with smaller explosive charge （227 kg TNT and 454 kg TNT）, the main energy consumption mechanism of the bridge deck was the top plate and top plate U-ribs, accounting for over 70% of the total energy consumption. In scenarios with larger explosive charge, the main energy consumption mechanism of the bridge deck involved the top plate, top plate U-ribs, cross beams, bottom plate, and bottom plate U-ribs, accounting for over 90% of the total energy consumption.

Prefabricated concrete building is a kind of green environmental protection building which can improve production efficiency and save energy. In order to study the seismic performance of prefabricated concrete bolt welding and Z-shaped joints, this paper carries out low-cycle reciprocating load tests on middle joints, observe the failure of specimens, and analyze the load-displacement hysteretic characteristics, ductility, stiffness and energy dissipation capacity of middle joints. The test results show that the hysteretic curve of the specimen is full in shape and has significant slip and pinch phenomena, and the ductility coefficient of each joint meets the requirements of the code for displacement ductility and has good seismic performance. The connection mode of joints has a great influence on the stiffness degradation of joints, and the joints of fully fabricated concrete frames have good deformation performance and anti-collapse ability under seismic load.

With the development of high-rise building related technology and the improvement of living standard, while the seismic safety of high-rise buildings being focused on, greater demands are put forward for their comfort under wind loads. Evaluation of building comfort is subjective and uncertain, which needs a huge amount of literature review and analysis to develop more appropriate comfort evaluation standards. In this paper, based on the existing codes and engineering cases of high-rise buildings, the comfort standards and evaluation methods worldwide were systematically sorted out and their applications were summarized. With the analysis of the standards and cases, the problems and deficiencies in the existing comfort evaluation standards in China are proposed. Then the solution and future research directions are put forward. It is expected to provide the reference for the development of building wind-induced vibration comfort standards for high-rise buildings in China.

In this work the temperature of two side walls of a subway station under construction in Shenzhen was monitored, and then the temperature fluctuation characteristics caused by the heat of hydration in the large-volume concrete structure of the side wall of the subway station were analyzed. Then the phenomenon of concrete interior and surface, surface and environment, cooling rate and other phenomena was further analyzed, and the temperature change law of concrete was obtained. ABAQUS finite element software is used to simulate the whole temperature change process. A three-dimensional stress field-temperature field coupling model of the side wall was established, and the result was compared with the experiment data to verify its reliability. The stress state of concrete was analyzed, the principle of temperature stress was verified, the stress concentration of the subway side wall was predicted, and relevant measures to prevent cracks was proposed.

Based on the theory of one-time sampling inspection, balancing the risks of the manufacturer and the user, and considering the protection of the interests of the manufacturer, it is proposed that the evaluation coefficient k for strength average value should be corresponded to 90% the equivalent assurance rate （0.9 Quantile value） for both the known standard deviation method and the unknown standard deviation method, and the sampling scheme when the standard deviation is unknown is determined based on Bayesian theory. When the sampling size is very small, the acceptance criteria of non-statistical method is established based on the average quality standard deviation, and the minimum value acceptance criterion is proposed according to the theory of one-time sampling inspection. Using the concept of Bayesian method, the samples in the previous inspection cycle and the current inspection cycle are combined to expand the sample size and improve the test efficacy of the acceptance criteria with known standard deviation. Bayesian method is adopted to comprehensively consider the average quality standard deviation and the standard deviation of measured samples to improve the test efficacy of acceptance criteria of non-statistical method. The acceptance criteria proposed in this paper have a more clearly statistical basis. The unified equivalent guarantee rate is used to keep the test efficacy close to each other, and the Bayesian theory is used to unify the various methods into the statistical method with unknown standard deviation. The case analysis shows that the acceptance criteria proposed in this paper are slightly stricter than those in GB/T 50107—2010, but the variation range is within the acceptable range; after adopting reasonable prior standard deviation, the Bayesian improved method proposed in this paper can obtain scientific and reasonable evaluation results.

Tunnel engineering accounts for a large part of the road and railway projects in the dangerous mountains in southwest China. This area has large tunnel burial depth, complex geological conditions and frequent seismic activities. There are several engineering problems with small angle crossings between tunnel engineering and active faults. In addition, near-field earthquakes have different influences on surrounding rocks with different burial depths. Therefore, near-field earthquakes of active faults have significant adverse influences on the smooth construction and safe operation of tunnel engineering. Therefore, based on the impact of multiple disastrous earthquakes at home and abroad on tunnel engineering, the influence rules of historical earthquake magnitude on the damage of surrounding rock （surrounding rock burial depth, lithology and grade） of tunnels passing through the seismogenic fault are analyzed and summarized. Combined with the characteristics of active faults, the ground motion records that can reflect the regional fault characteristics and pulse characteristics are obtained. Finally, the finite difference software FLAC3D is used to study the influence of the active fault near-field earthquake on the surrounding rock of deep tunnel engineering. The results show that the tunnel surrounding rock is more stable with the increase of tunnel buried depth, which can restrain the plastic deformation of tunnel surrounding rock. The trend of maximum shear stress and maximum principal stress under different ground motions is basically the same, and the stress of tunnel surrounding rock in fault section is greater than that in ordinary section. The surrounding rock of Grade IV and below has a great displacement and stress response when the depth of tunnel is 200m and PGA is larger than 0.3g. The response level increases with the increase of PGA, and there is a large increase of nearly 50% in the process of PGA from 0.2g to 0.39g. This process is the main process of tunnel plastic deformation, and the area of plastic zone gradually increases with the increase of PGA. Therefore, the influence of near-field earthquakes should be carefully considered in deep-buried tunnels through active faults. The research results can provide technical support for seismic optimization design of tunnel.

This paper presents an experimental study on the self-healing effect of Engineered Cementitious Composites （ECC） under various conditions. First, specimens were fabricated using two different categories of fibers, and subjected to uni-axial tensile loading to reach different levels of pre-damages （non-linear strain）. Then the specimens were treated in different curing conditions for self-healing. Finally, a series of tensile tests were conducted on the self-healed specimens to evaluate changes in peak tensile strength, tensile strain capacity, tensile modulus and etc. The test results shows the damaged ECCs after healing treatment restored their tensile strength, tensile strain capacity to a certain degree and partial tensile modulus. The damage level, fiber category and curing condition have significant effects on the mechanical properties of ECC after healing.

As a novel structural system, the continuous rigid frame bridge without bearings has the advantages of good integrity and no requirement for replacement and maintenance of the bearings. However, the pier-beam connection joints of this type of bridges are complex and prone to damage and destruction under seismic excitation, while the cross-section of girders are substantially greater than the pier cap beam. To date, seismic performance of such joints is scarcely investigated around the world. Utilizing a 4×40m continuous rigid bridge without bearings in a standard section of an intercity railway as prototype, quasi-static tests were conducted on a 1/3-scaled connection joint model, to investigate the damage mode, hysteretic energy dissipation characteristics, and ductility capacity, as well as the failure mechanism under closing and opening bending moment. The observed results show that at the beginning of the test loading, horizontal cracks were mainly generated at the loading surface of the pier, and then gradually extended through, with fewer cracks developing at the diagonal edges of the joint and girder. As the loading displacement increases, cracks with small width gradually appeared at the diagonal side. Since the longitudinal reinforcement of the pier extended into the joint is only transversely designed with tie bars and no hoops, the significant arch damage was observed for the concrete at the top of the joint when subjected to closing moment. The force-displacement hysteresis curve was observed with small area with severe pinch effect. Although the longitudinal reinforcement at the top of the pier yielded when the joint was damaged, the ductility capacity was limited. Under the closing moment, the skeleton curve did not contain an obvious yielding plateau, and the lateral force experienced a sudden drop after reaching the peak, indicating the damage of the joint. Finally, based on the damage mode and damage mechanism, the reinforcement configuration of the side pier-main beam joint is suggested in conjunction with the AASHTO code.

In order to investigate the dynamic response of the airport taxiway base under the combined excitiation of aircraft taxiing load and underpass subway running load. Based on the real-time monitoring of a taxiway in a coastal soft soil airport, acceleration sensors were placed near the subway line crossing the taxiway to obtain the dynamic response of the taxiway. The response signals of long and short period frequencies corresponding to subway loads are obtained by separating the response signals, and the main frequencies of the dynamic response of subway and aircraft are separated by comparing the amplitude of the long and short frequency signals in the frequency domain. The results show that the main frequency of dynamic response of aircraft is 5‒30 Hz, and that of subway is 30‒60 Hz. The dynamic response produced by the aircraft taxiing load to airport runway is more than 6 times that produced by subway crossing.

The pushover analysis has the advantages of being easy to operate, having low computational costs, and being able to describe the overall nonlinear behavior of structures well. It is an engineering practical analytical method worth promoting and applicable for seismic performance-based design of general multi-story and high-rise building structures. However, this method has limitations such as difficulty in considering the influence of higher modes, significant differences in structural responses under different pushover force distribution patterns, and errors introduced by single-degree-of-freedom equivalence, which restrict its application in complex and irregular high-rise building structures.This paper considers the contribution of both fundamental and higher modes to the seismic response and combines the modes corresponding to sensitive modes into a final pushover force distribution pattern. This method is used to analyze the nonlinear seismic response of an oversized podium offset single-tower super-high building structure and is compared with the results of dynamic nonlinear analysis. The results show that the proposed method has good accuracy in predicting both the overall response of the structure and the yielding damage patterns of local components, with the additional benefits of high computational efficiency and strong applicability.

The rebound method has the advantages of no damage to the structural components, a large number of samples and flexible layout of the test area. However, the mean value and variance of the inspected strength may have a large deviation, so the accuracy of the strength characteristic value of the inspection batch estimated by the sampling inspection by variables is poor. According to the principle of single sampling inspection by attributes, based on the analysis and comparison of sampling characteristic curves, the estimation method of characteristic value of concrete strength of inspection batch is established considering that the acceptance probability of 0.1 unqualified product rate is 50% （the confidence level is 0.5）. The comparison of sampling characteristic curves and case analysis show that the estimation results of the proposed method is basically equivalent to that of sampling inspection by variables based on Bayesian method. Suggestions are put forward for optimizing the layout of rebound test area when evaluating the strength of test batch concrete, as well as the core drilling correction method for inspection results of rebound method by sampling inspection by attributes. The proposed method has the characteristics of accurate probability definition, avoiding the assumption of strength distribution type and variance calculation, and reducing the number of core drilling checks. It can be used in engineering quality compliance assessment and existing structure safety assessment.

A method for calculating the reliability index of structural components, which is convenient for use in commercial structural design software, is proposed in this paper. The finite difference method is used to calculate the partial derivatives of load effects on basic random variables. The moment propagation method is used to calculate the first and second moments of components' load effects. The first order second moment method is used to calculate the reliability index β of structural components. A secondary development procedure based on PKPM is written according to this method, which can calculate K and β of beams considering ultimate bending and shearing capacity in RC frame structures. The reliability index of an RC frame structure with a seismic fortification intensity of 6 is calculated using this procedure. The result shows that a few beams' reliability indices do not meet the code requirement under an earthquake with an intensity of 6, and under an earthquake with an intensity of 7,the reliability indices of most of the beams are lower than the code limit.

As the civil engineering industry undergoes a significant transformation, intelligent technologies have introduced novel technical means and tools for the innovation and advancement of structural health Monitoring （SHM） in civil engineering, thereby broadening the research scope in various aspects of SHM systems. This paper systematically sorts out and comprehensively reviews the current status of research on intelligent technologies applied in the field of SHM, covering areas such as computer vision, machine Learning, intelligent robots, and drones. Based on the review of existing research results, this paper looks forward to the development trends and prospects of intelligent technologies in the field of SHM, and deeply explores the innovations and challenges brought about by the integration of SHM and intelligent disciplines.

Spatial-cable suspension bridges consist of main cables and hangers inclined either to the inner or outer side in the transverse direction of the bridge. The hangers play a vital role in load transmission; however, their resistance decreases with the bridge's service life, leading to an increase in component failure probability and structural safety concerns. In this study, a steel box girder suspension bridge with a main span of 1666m serves as the engineering background, and seven designs of the suspension bridge with different inclination angles of main cables are proposed. By establishing the time-varying probability models of the resistance, internal forces under dead load and internal force under wind load only, the variation of the reliability index of hangers with the service period under the condition of the dead load and the extreme static wind load is analyzed and compared. The study shows that within ten years of the steel wire starting to corrode, the distribution of resistance of hangers affected by uniform and pitting corrosion does not reject the gamma distribution. From the 10th to 30th year, the distribution of resistance of hangers does not reject the Weibull distribution. The distribution of internal force of hangers under wind load only does not reject the logarithmic normal distribution within 40 years of service. The time-varying reliability index of all the hangers of the suspension bridge is uncorrelated with the inclination angle of the cables, and the variation of the time-varying reliability index of the hangers at different positions of the same suspension bridge is consistent.

Rebound method, core drilling method and rebound-core drilling correction method are commonly used in-situ concrete strength non-destructive detection methods, but the variance of concrete strength detected by rebound method is smaller than that by core drilling method, which is a common phenomenon in engineering practice. How to use the reasonable variance in the estimation of the strength characteristic value of the measured concrete directly affects the accuracy and rationality of the estimation result. Based on the statistical analysis of 120 existing structural concrete strength rebound core drilling correction method, the statistical parameters and their distribution rules of core drilling method and rebound method are obtained. It is suggested that 90% equivalent assurance rate should be adopted for the characteristic value of concrete strength in situ, and the evaluation coefficient corresponding to 0.1 quantile value is obtained by using Bayesian total probability formula. According to the mixed variance of rebound and core drilling method in the check area, and the calculated posterior variance by combining with the prior variance, the Bayesian estimation method of strength characteristic value of rebound-core drilling correction method is established, and the Bayesian estimation method of strength characteristic value of rebound method and core drilling method is obtained after simplification. Through the verification and analysis of the measured data of new projects and existing structures, it is shown that the Bayesian estimation method of strength characteristic values proposed in this paper is reasonable and accurate, which overcomes the defects of large error in variance value and insufficient sampling quantity in the current standard, and can be used in engineering quality compliance assessment and safety assessment of existing structures.

The Wujiang Rolling Pedestrian Bridge project is located at the border of two provinces and one city in the eastern part of Wujiang District. It is the main exit for yachts entering and exiting Yuandang Lake at the planned water town market node. It has high landscape requirements and requires a landmark architectural landscape pedestrian bridge. The bridge also has requirements for opening, so the rolling pedestrian bridge scheme is finally adopted after considering various factors. This paper introduces the special geographical location, scheme conception, navigation conditions, overall design, structural design, hydraulic design, opening sequence, etc. Through research, the project has achieved the expected landscape and opening performance goals, and the specific analysis methods and conclusions can be used as a reference for similar projects.

To study the influence of pile-soil interaction （PSI） on the near-field pulse seismic response of high-speed railway bridge-ballastless track system, the finite element model of the bridge-track system was established by ANSYS. The influence of PSI on the seismic response of the system was analyzed from three aspects： the natural vibration characteristics of the system, the post-earthquake residual displacement of each layer of the system and the key components between layers and the envelope displacement during the earthquake. The results showed： the natural vibration period of high-speed railway bridge-ballastless track system is extended considering PSI; the post-earthquake residual deformation and the seismic peak envelope deformation of each layer of main beam, base slab, track slab and rail are different considering or not considering PSI, and the post-earthquake residual deformation and the seismic peak envelope deformation of each layer of the track structure on simply supported beam and continuous beam bridge change alternately along the mileage direction; the influence of PSI on the key components such as fasteners, mortar layer, sliding layer and lateral blocks is obvious, especially for the key components with small stiffness. The influence of PSI on the key components between layers of the bridge-ballastless track system should be focused on in the anti-seismic checking calculation.

Earthquake monitoring networks has been established in Yibin area. A dense earthquake monitoring network for town and township is formed by eight monitoring stations in the rural region prone to seismic activity. Different from traditional strong-motion arrays, each station contains ground point and floor point of adjacent school buildings. A total of 2 000 records of ground and floor acceleration signals induced by 136 earthquakes were obtained, categorized into four types based on signal characteristics： epicenter zone, near zone, far zone, and very far zone signals. The data from the epicenter and near zone signals are valuable strong ground and floor acceleration signals and of large amount, with 56 records of ground and floor signals in region with epicenter distance less than 10 km. This paper selects representative data to analyze the characteristics of ground average response spectrum. The typical attenuation curve of peak ground acceleration with respect to epicenter distance is given. The very far zone and far zone signals with relatively lower peak values of ground and/or floor acceleration are also discussed.

In order to investigate the effects of different factors on the seismic response of steel plate silos when considering the storage-wall interaction, this study analyses the structural acceleration response, displacement response, the structural energy consumption and the structural strain response of the steel plate silos under the full-filled storage and the half-filled storage state, by establishing three steel plate silos with different height-to-diameter ratios. Moreover, steel plate silos and reinforced concrete silos with the identical dimensions are modeled and exited by the same seismic waves to compare the differences in structural acceleration response, displacement response and energy consumption of the two silos in the half-filled and full-filled conditions. The results indicate that the peak absolute acceleration and peak relative displacement of the silo wall increase with the increasing height to diameter ratio and reach a maximum at the top of the silo. While the cumulative hysteresis energy dissipation and stain of the silo decrease with the increasing height to diameter ratio. Moreover, for different silo types, the response of the reinforced concrete silo is smaller than that of the steel plate silo.

A crack detection method for cylindrical members based on binocular stereo vision and spatial projection restoration is proposed. By this method, the image point of the crack edge on the image plane of the left camera is selected as the projection point, and the side surface of the cylindrical member is selected as the projection cylinder surface. Based on the obtained world coordinate of the projection point and the equation of the projection cylinder surface, the world coordinate of the actual crack edge point can be obtained by calculating the intersection of the line connecting the coordinate origin and the projection point and the projection cylindrical surface. In this way, the spatial shape of the crack can be restored, and further, based on this, the characteristic value of the crack can be detected. The method proposed can realize oblique photography of cracks, truly restore the original spatial shape and size of cracks, and improve the recognition accuracy of cracks. At the same time, this method only needs to perform binocular camera calibration once and perform stereo matching on a limited number of feature marker points based on their geometric features to obtain all the required calculation parameters. It has high computational efficiency, good matching effect, and the detection accuracy is not sensitive to illumination changes. This method solves the defect that the traditional 3D reconstruction technology based on binocular stereo vision is difficult to directly extract the crack boundary on the 3D point cloud of the structure surface, and is suitable for crack identification and parameter extraction of cracked surface of cylindrical members.

In order to improve the safety of component hoisting construction, this study explores a three-dimensional reconstruction method for prefabricated building component hoisting construction scene under multi-directional threshold. This method uses a 3D laser scanner to obtain scene point cloud data, uses the minimum curvature region growth method for scene segmentation, and uses a random sampling consistency algorithm for image fine segmentation to obtain a set of several disjoint planar point cloud regions. Using the moving least squares method for surface fitting, a three-dimensional parameter optimization model for construction scenes is established. By improving the sparrow search algorithm to solve the model, the optimization results of 3D model parameters are obtained, and the iterative reconstruction of the construction scene of prefabricated building component hoisting is realized. The experimental results show that this method can effectively collect point cloud data from component lifting construction scenes and achieve high-precision 3D reconstruction of construction scenes.

The amount of domestic construction spoil emission is significant, but the resource utilization rate is low. One feasible and high value-added way to utilize construction spoil is to produce nonsintered bricks. Firstly, the classification and main disposal methods of construction spoil are introduced, and the bottlenecks such as low-carbon dewatering of construction spoil raw materials and the difficulty of determining the process parameters are pointed out. Then, the common production process of nonsintered bricks along with the influence of molding, curing and other processes on the performance of nonsintered bricks are introduced. Next, the type of cementitious material and mixing, moisture content, admixtures and other factors on the mechanical performance of nonsintered bricks are further analyzed, and the resource reuse and low-carbon advantages of nonsintered bricks are summarized. The defects such as smooth surface not easy to combine with mortar, low shear strength, large dry shrinkage deformation, etc. are also reviewed. Finally, the future direction of research on nonsintered bricks from the perspective of green building is put forward.

The integrity analysis of the reactor plant under steam explosion was numerically studied for the potential safety problem of the cavity.Firstly, a refined reactor plant finite element model （FEM） was established, and verified comprehensively based on a slab explosion test.Secondly, the damage scope of the reactor plant under steam explosion was determined qualitatively based on the damage contours.Then, the damage mechanism of the reactor plant was revealed based on the displacement- and strain-time histories quantitatively.Next, the tightness performance of the nuclear containment was analyzed according to the tensile strain contours and the damage threshold.Finally, the influence of foundation strength on the blast resistance of the reactor plant was analyzed and recommendations for the design of the nuclear power plant （NPP） were proposed.It derives that： under steam explosion, the cavity wall endures complete damage and the main damage mode is tensile failure.Besides, concrete at the cavity bottom within the depth of 2 m enters plastic state with shear failure; under steam explosion, the NPP containment is safe and the tightness of the containment is good.

The special-shaped building located on the steep slope is difficult to be realized with the conventional structure supported by foundations with different elevations or stilted building structure. Aiming at the special-shaped building under this terrain, a arch with inclined column structure was proposed and designed, which can not only better adapt to the architectural shape, but also solve the problem of foundation setting. Aiming at this structure, the influence of key parameters such as arch axis shape, arch rise-span ratio, arch tilted angle and column tilted angle on the mechanical performance and arch warping effect were analyzed in detail by using parametric analysis method. The results show that rise-span ratio has little influence on the bending moment of the arch and great influence on the axial force of the arch. Meanwhile, rise-span ratio also has great influence on the stability of the structure. Considering the architectural effect, structural force and structural stability, the rise-span ratio of the arch should be controlled between 0.2 and 0.3. When the rise-span ratio of arch is between 0.2 and 0.3, the influence of arch axis shape on structural stress can be ignored. With the increase of arch tilted angle, the section torque of arch increases rapidly, and the warping effect of arch foot and vault is obvious. When checking the strength of steel box section, the warping effect should be considered. The increase of column tilted angle reduces the internal force of arch, which is conducive to the stress of arch, and the stress of the structure can be improved by adjusting the tilted angle of the column.

Precast concrete double skin shear wall （PCDSSW） is a new-type semi-prefabricated concrete structure element with sound structural integrity, high construction efficiency and low demand for formwork and labour. It consists of two precast concrete panels and one cast-in-place （CIP） layer between them. In order to investigate its mechanical behavior under lateral loads, finite element simulations were conducted using the software ABAQUS after the models had been proved reliable by comparison with the existing test data. The parameter analysis of vertical connections, design axial compression ratios and the concrete strength of CIP layers were carried out on 21 PCDSSW models. Analysis results indicated that the load-displacement curves of the walls with single-row dowel bar connection, double-row dowel bar connection and those without dowel bars in the middle walls were similar. The lateral load capacities of the walls with single-row dowel bar connections were 1.5%~7.5% higher than those with double-row dowel bar connections, and the capacities of the walls without dowel bars in middle walls were 5.7%~12.3% lower than those with double-row dowel bar connections. Secondly, the initial stiffness and load capacities of walls increased significantly with the axial ratios, while the load capacities and stiffness declined more rapidly under high axial ratio. In addition, low concrete strength of the CIP layers caused by insufficient vibration would lead to low load capacities, which should be avoided in construction.

This paper is based on the engineering background of super-tall towers in earthquake prone areas, comprehensively arranges the position, various deformation amplification devices, viscous damping parameters and other key contents to carry out the selection and analysis of viscous damping systems under wind and earthquake double excitation. Taking a 396 m super-tall tower as an example, the design of viscous damping systems under wind and earthquake double excitation is studied. Research has shown that viscous damping vibration reduction systems have a certain control effect on different modal responses, which can effectively improve the comfort, stiffness, and strength performance of structures under wind and earthquake conditions. Reasonable placement of dampers, deformation amplification devices, and parameter selection can achieve more efficient vibration reduction efficiency.

Textile Reinforced Ultra High Ductile Cementitious Composites （TR-UHDCC） are advanced materials characterized by high strength, high ductility, crack resistance, and durability. Compared to traditional masonry reinforcement materials, TR-UHDCC exhibits superior performance. Based on existing experimental research results, this paper introduces the Hashin damage criterion to account for the damage behavior of the fiber grid, establishing a three-dimensional finite element model for TR-UHDCC. This model accurately simulates the stress-strain curve of TR-UHDCC and its corresponding characteristic points （cracking stress and strain, peak stress and strain, ultimate stress and strain）. Using this model, the effects of fiber grid distribution rates and the tensile strength of UHDCC on the characteristic points of TR-UHDCC were studied. Finally, a theoretical calculation model for the tensile load-bearing capacity of TR-UHDCC was developed based on the sectional force equilibrium relationship. The calculated values from this model align well with experimental and parametric analysis results, with an average error of only 3.63%.

The application of cold-formed steel in prefabricated structures has inherent advantages. In order to expand the range of use of cold-formed thick-walled steel structures and avoid its shortcomings, this paper designed six new layered assembled “cross-shaped” beam-column joints and conducted cyclic loading tests to investigate the failure mode, initial stiffness, skeleton curve, equivalent viscous damping coefficient, energy dissipation coefficient, secant stiffness, hysteresis curve and strain distribution in key parts of the beam-column joints. The main conclusions were drawn as follows： Through the sliding of bolts and node plates, semi-rigid nodes have a certain energy dissipation capacity. Adding high-strength bolts can improve the bearing capacity initial stiffness and energy dissipation capacity of beam column joints as well as avoid bearing pressure on the bolt hole between the beam end and the connecting plate. Adding replaceable node flange plates has no significant impact on the failure mode of beam column joints, but significantly improves their bearing capacity, energy dissipation capacity, and initial stiffness.

The flat grid structure is widely used in large-span spatial steel structure system because of its good integrity, large spatial stiffness and flexible layout. The research focuses on the evaluation and reinforcement of a flat grid structure's bearing capacity, which is critical in cases of member damage due to factors such as material aging or construction issues. In this paper, SAP2000 finite element software is used to analyze the stress of a typical orthogonal square pyramid grid structure. According to the change law of mechanical index of grid structure after damage of different positions and numbers of members, a new calculation method of damage factor of grid structure is proposed. The calculation method has fewer parameters, simple calculation and high accuracy. The method of evaluating the bearing capacity of the grid structure and determining the repair measures according to the structural damage factor is proposed. For the grid structure that needs to be reinforced, this paper proposes a reinforcement method based on the importance of members.

In order to determine the performance difference of the network tied-arch bridge with different deck structure, three types of bridge deck structure, namely concrete deck, orthotropic steel deck and steel-concrete composite deck, are used to design and study the 300 m span bridge. The finite element software ANSYS was used to establish three trial design scheme models, and compare their overall mechanical performance. At the same time, the amount of materials was counted, and the unit price of materials was introduced to compare their economic performance. The results show that the concrete deck has better economic performance for the 300 m network tied-arch bridge. Compared with orthotropic steel deck, concrete deck or steel-concrete composite deck can improve the structural stiffness to a certain extent. The distribution of internal force and stress along the longitudinal direction of the network tied-arch bridge is similar in different types of bridge deck, while the axial force of the structure and cable force at the bridge completion stage is significantly different.

Cement-based materials containing fiber are widely used in engineering structures. In order to study the bonding properties between steel fibers and cement matrix, this research investigated fiber pullout performance of steel fiber in cement mortar and high-strength grout. The bonding properties were evaluated by the indexes of maximum pullout load,energy dissipation and average bond strength. The test results show that the shape of the pullout load displacement curve in the high-strength grout is similar to that of the ordinary cement mortar. The mechanical anchoring effect exists between the deformed fibers and the matrix, and the maximum pullout load and energy dissipation are significantly increased compared with that of the straight fibers. Compared with the straight fiber, the average bond strength and energy disspation of the hooked fiber of ordinary cement mortar matrix are increased by 180.8% and 126.8%, respectively. In high-strength grout, the increase is 363.3% and 474.7% respectively. When the steel fiber has an inclination angle, the process of the pullout is usually accompanied by the spalling of the ordinary cement mortar matrix and the plastic deformation of the steel fiber. The increase of embedding depth will increase the pullout load and energy dissipation, but it may cause the fiber breakage for the waved fiber.

The beam deflection control in current structural design standards is to ensure the serviceability function of the building, while the deflection limit value in the reliability assessment of existing structures and the deflection early warning value in structural health monitoring also have the purpose of controlling the safety of structural members. Aiming at the safety control of structural members, this paper established a theoretical relationship between the deflection to span ratio of beams and the maximum tensile strain of steel bars,and the calculation methods and recommended values of the mechanics characteristic coefficient, the section neutral axis height coefficient and the long-term deflection growth coefficient of the beams were studied. The relationship between beam deflection and maximum tensile strain of steel bars was verified by the experimental data, which showed that the accuracy of the comprehensive coefficient of the deflection to span ratio proposed in this paper meets the requirements of engineering calculation. The graded control method of maximum tensile strain of steel bars was established, and the graded limit of deflection to span ratio of beams was proposed accordingly. Compared with the deflection limits in current standards, the results showed that the deflection limits proposed in this paper are significantly different according to the specific characteristics of the beams. The range of the deflection limits is wider and more stringent than the current standards. The research findings in this paper can provide references for reliability assessment of existing structures and structural health monitoring.

To investigate the influence of milled-cut steel fiber （MSF） on the flexural behavior and toughness of plain concrete, four-point bending tests were conducted on C50 concrete matrixes with different volume fractions of steel fiber （0%,0.6%,1%,1.4%）. The flexural behavior,cracking mode,and failure mechanisms of milled-cut steel fiber reinforced concrete （MSFRC） was analyzed. The evaluation methods for flexural toughness of fiber-reinforced concrete in domestic and international standards were studied to assess their applicability. The results indicate that the maximum equivalent flexural strength of the MSFRC is 1.8 times than that of plain concrete. Upon surpassing the critical fiber volume fraction of 1%, the material displays multiple cracking characteristics,with strain hardening behavior observed at an enhanced fraction of 1.4%. The method specified in JG/T 472—2015 steel fiber reinforced concrete is applicable for characterizing the flexural toughness of milled-cut steel fiber reinforced concrete. The increase in fiber volume fraction enhances the flexural deformation capacity of concrete and improves the post-cracking flexural toughness within the small deflection range.

The frame-shear wall structure system was used in Photoelectric Information Building in Huazhong University of Science and Technology. A long-span structure with a span of 40 m was accomplished by using a multilayer vierendeel truss crossing 4 floors. The structure involved with structural irregularity problems such as the torsion irregularity, eccentric arrangement, slab with large opening, mutation of the bearing capacity, discontinuous structural elements, and regional skip-floor columns. A comparative study on the braced truss and multilayer vierendeel truss was conducted in this paper. The mechanical mechanism, internal forces of elements under vertical load and vertical seismic action, comfortability of the slab, design of the complex joint, the construction technique requirements, and behavior under rare earthquakes were analyzed. The measures were developed to reinforce the seismic capacity of the structure. The structure scheme of the multilayer vierendeel truss not only can meet the requirements of relevant codes and achieve the expected objective of seismic performance but also can meet the requirements of architectural function.

In the current research on seismic reduction design of school buildings using viscous fluid dampers, attention is often paid to the main structures such as teaching buildings and dormitory buildings, while neglecting the corridor space that plays an important role in the overall spatial organization of the campus. In order to study the application of viscous fluid damper in school corridor space, this paper takes the corridor space between teaching buildings in a primary school in Shanghai as an example for seismic reduction design. Firstly, conduct frequent earthquake analysis on the structure, and the results meet the requirements of the specifications. Secondly, conduct elastic time history analysis under fortification earthquakes and compare the seismic reduction effects when including the foundation layer or not, the arrangement of dampers in the inner or outer frame, the number of dampers changed, the floor of dampers changed, and determining the seismic reduction plan. Finally, conduct elastic-plastic time history analysis under rare earthquakes to calculate structural damage, energy dissipation, and drift ratio. The research results indicate that viscous fluid dampers can provide certain energy dissipation under earthquake action and are an effective seismic reduction method for school corridor spaces.

To study the bearing capacity, deformation, and failure pattern of steel tube specimens filled with aluminium foam under quasi-static axial load, specimens with different lengths and thicknesses were tested, and the final failure pattern and axial force-displacement curve were obtained. On the premise of the reliability of the finite element numerical model, the influence of the section height of the steel tube filled with aluminium foam was analyzed. The research results show that the peak load and average load decrease with the increase of specimen length, whereas increase with the increasing thickness of the steel tube. Compared with the pure steel tube, the total energy growth rate of the steel tube specimen filled with aluminium foam with a cross-section height of 40 mm, 50 mm, 60 mm and 70 mm fluctuates within a certain range, and the steel tube specimen filled with aluminium foam with larger height-to-width ratio of section can resist deformation more effectively. The mechanical properties of the aluminium foam-filled steel tube specimen with a length of 150~250 mm and a rectangular section aspect ratio of 1.5 are best after buckling.

GFRP bar-UHPC members have excellent mechanical property and durability, and have wide application prospects. The bond performance between GFRP bars and UHPC is a key issue for the two materials to work together. Pull-out tests were carried out on 12 and 4 GFRP-bar-UHPC specimens under monotonic and low-cyclic loading respectively to study the effects of GFRP bars' surface treatment, bond length and cyclic loading on mechanical properties such as failure mode and bond strength. The results showed that all specimens exhibited pulling-out failure. The bond stress-slip curves of wire wrapping GFRP bars specimens exhibited more significant fluctuations up and down after the peak load. The bond strength between GFRP bars and UHPC decreases slightly with the increase of bond length. The bond strengths of wire wrapping GFRP bars specimens were higher than these of sand coated specimens. Meanwhile, the effect of low-cycle loading on the bonding properties of GFRP bars in UHPC was mild. Finally, based on a model proposed by Yoo, a bond strength prediction model considering surface features of the bar has been proposed.

Based on the nacre toughing mechanisms, Engineered Cementitious Composites （ECC） were used as constructing mortar to improve the ductility and toughness of masonry structure. Five groups of masonry prisms with four types of bricks were carried out. The failure mode, stress-stain curve, ductility and toughness were comparably analyzed. The results demonstrated that the nacre-inspired masonry prisms had interface-slip and crack-deflection failure mode, which increased the ductility by a maximum of 10 times and the energy consumption capacity by a maximum of 77 times compared with conventional masonry. However, the brittle splitting failure occurred when ECC layer couldn’t provide sufficient confinement with the strength increease of brick layer. Based on the Digital Image Correlation （DIC） method,the collaborative work characteristics between brick and ECC lager was studied and the toughing mechanism was also discussed.