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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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.

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.

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 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.

Based on scaled physical model tests and three-dimensional finite element numerical simulation, the lateral bearing capacity and failure characteristics of grouted sleeve connected bridge piers for overpasses were studied, and their energy dissipation characteristics were explored. The cyclic loading test results of the grouting sleeve connected pier column indicate that there was no node failure before the pier column failure, and its mode was column bending failure. A refined finite element analysis model for grouted sleeve connected bridge piers was established, and an elastoplastic damage constitutive model for concrete was introduced to simulate the mechanical response and damage process of the bridge piers under reciprocating cyclic loads. Further analysis was conducted on the influence of axial compression ratio and prestressing level on the bearing capacity of bridge piers. The results showed that a high axial compression ratio is beneficial for improving the lateral bearing capacity of grouted sleeve connected bridge piers, but it will reduce their energy consumption and ductile deformation performance. Pre stressing can increase the lateral bearing capacity of bridge piers, slightly increasing their energy dissipation capacity, but reducing their ductile deformation capacity.

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.

Chinese mortise and tenon joints present significant historical and cultural value. Recently, BIM-based structural parametric design has been increasingly promoted and applied. Through the digital model, the entire life cycle of traditional structure will be recorded for their conservation. This paper summarizes the shape characteristics of typical mortise and tenon joints. Based on dimension feature, family templates of mortise and tenon joints were developed on the Revit platform, which improves modeling efficiency and accuracy.

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.

The current structural fire resistance research has relatively few studies for localized fire scenarios, and the test results are relatively scarce. Based on this, this paper attempts to build a realistic fire test platform, and adopts two fire source forms, jet fire and pool fire, to heat the H-shaped columns and record its thermal results. In terms of numerical simulation, unlike the iterative coupling method that applies the concept of adiabatic surface temperature, this paper realizes the two-way direct coupling of fluid-solid heat transfer by unifying the fire analysis with the thermal analysis using the CFD method. The distribution rules of the spatial velocity field and temperature field were explored in the fire analysis model, and the thermal characteristics of steel columns in different fire source environments were explored in the thermal model. The correctness of the direct coupling method was verified by comparing experimental data with simulation results. In addition, the theoretical and empirical formulas are applied to explore the distribution law of convective heat transfer coefficient of the steel column surface.

The bearing capacity of the existing wall after plugging reinforcement is studied. Considering the influence of stress lag effect, original stress level, opening rate and plugging material performance on the bearing capacity of the masonry wall after plugging, the corresponding calculation method is given. The results show that the use of the original masonry mortar and block materials can not meet the bearing capacity requirements of the wall ; improving the strength of masonry mortar and block materials can only meet the bearing capacity requirements of some walls ; the use of high ductile concrete to reinforce the wall is an effective means of repair, but there is also the possibility that it cannot meet the demand for bearing capacity.

On the basis of the parallel four-cable suspension bridge, four-cable suspension bridge with different sag solves the construction problem of limited height of the bridge tower, and lowers the main cable under the deck to maximize the sag of the main cable. As the critical load-bearing member of the suspension bridge, the axial force effect of the main cable under vehicle load deserves attention. Taking a four-cable super-span suspension bridge with different sag under construction in China as the research object, a structural finite element model is constructed by ANSYS, and the mechanical performance of four cables under vehicle load is analyzed. The results show that the distribution of dead load in cables with different sag is uniform. Under the action of symmetrical vehicle load, the lower cable will bear more vehicle load, with a distribution ratio of about 26.2% and the upper cable about 23.8%. Under the action of asymmetric load, the axial force of the lower cable on the action side can reach 34.6% of the total axial force, which is about 32% higher than that under the symmetrical load. The load distribution ratio of vehicles is independent of the change of traffic volume and the weight distribution.

Offshore wind turbines （OWTs） are subjected to random wind and wave loads for a long time during use and are in a state of continuous vibration. The design of their dynamic characteristics is very important. A three-dimensional finite element model for frequency analysis of an actual monopile support structure for the offshore wind turbine under actual seabed foundation condition was established by using ABAQUS. Compared to commonly used soil spring model,the model can consider the actual three-dimensional soil conditions directly and no need to simplify the soil artificially, avoiding errors caused by simplification.. The correctness of the method is verified by comparing the reference value. Unlike traditional optimization for the cross-section of support structures, the article considers changing the pile types. Four types of special-shaped piles, including an extended pile, a pile with a cover plate, and two types of piles with wings, were designed on the basis of the ordinary monopile. The influence of pile types on the natural frequency of monopile support structures for offshore wind turbines and the performance of support structures with different pile types under scour were studied. The results indicate that taking into account the effect of frequency increase and the difficulty of piling, the use of piles with a cover plate on any soil seabed is the optimal way to increase the frequency of support structures for offshore wind turbines. Scouring can reduce the frequency of the support structures, and the impact on the pile with a cover plate is the greatest, which requires special attention in design.

The inverted Fink truss bridge, a novel structural system first appearing in the United Kingdom, has seen a gradual increase in its application in urban landscape pedestrian bridge construction over the past decade. This system presents significant differences from typical cable-assisted beam systems such as cable-stayed and suspension bridges, with the main design parameters' influence on structural performance remaining unclear. This paper first introduces the development of the inverted Fink truss structure. Subsequently, it focuses on a newly constructed inverted Fink truss bridge with uneven tower heights, employing finite element numerical simulation to analyze critical structural parameters such as tower height and cable tension within the cable-assisted beam structure. It summarizes the influence patterns of these parameters on structural performance and proposes feasible directions for stiffness optimization of such structural systems. The findings of this study provide a basis for the structural design of inverted Fink truss bridges with uneven tower heights.

Due to the non-sufficient introduction on the derivation process of mass matrix of Timoshenko beam element in existed studies, the present study was initiated for the derivation of consistent mass matrix of Timoshenko beam element. Based on the Lagrange shape function and the virtual work, the theorical expression of mass matrix for each single motion state was given for the 2-node and 3-node elements separately, including the tension, torsion, bending-deflection and bending-rotation motions, and then the complete mass matrix was got by aggregation. Moreover, the simplified procedure in practical finite element calculation was also proposed for the tapered-section element. Another, the difference of the shape functions between the Timoshenko and Euler beam elements was also elaborated, as well as the difference in the derivation of the mass and stiffness matrixes concerning the bending condition. The results show that the Lagrange shape function was employed for all the deform conditions and especially the uncoupling of the deflection and rotation in bending conditions make the mass matrix for each single motion state shares the same form： each one is expressed by the corresponding section parameter and the same shape function. Additionally, the complete mass matrix based on this foundation is featured by the high degree of decoupling. For the tapered-section element, when the theoretical whole integration is simplified to be independent integration calculated by Gauss integration method in practical application, the obtained mass matrix shares the same form with the constant-beam element, just replacing the constant section parameters by the equivalent section parameters.

Connected structure is a common form of expression in modern architectural design. In this paper, the dynamic characteristics of towers on both sides of the connected structure are analyzed by taking a high-rise asymmetric twin tower as an example, which indicates the necessity of adopting the sliding connection in this project.At the same time, elastic analysis under minor earthquake, performance-based design, and elastic-plastic analysis under major earthquake are carried out for this project, with a focus on analysis of the connected structure, including force analysis, deflection analysis, finite element analysis of key points, and calculation of sliding support reaction and displacement. The results show that the structural design of this project is reasonable, the strengthening measures are effective, and the seismic performance can achieve the expected target. The connected structure has good mechanical properties, the structure is safe and reliable, and the design requirements for anti-collision and anti-falling are satisfied.

Isolated structures with rubber bearings have good seismic performance, and have been widely developed and applied at home and abroad in recent years. Scale model test method, as one of the important means to study and verify the performance of new structures or complex structures, plays an increasingly important role in the research and design of structural engineering and disaster prevention and reduction engineering. For model testing, using reasonable similitude method to carry out reasonable similitude design is the key to ensure the accuracy of the model test results. From three aspects of isolated superstructures, isolation layer and transfer layer, this paper focuses on the advances in the similitude design method for shaking table test of isolated structures with rubber bearings. At present, the dynamic similarity design of the superstructure model of the isolated structure generally refers to the traditional practical similarity design method. For the design of the isolation layer, it is necessary to revise the existing mechanical properties calculation formula of the isolation layer, and to select and arrange the number of supports according to the principle that the overturning stiffness of the isolation layer is similar. The reinforced transfer layer in the scale model can make the load area pressure of the support tend to be uniform and reduce the tensile probability of the support in rare earthquakes, and the effect should be considered in the seismic response analysis of isolated structures.

With the development of super-tall building structures, the economy has become the focus of the owners in the design. The core tube is an important component for lateral force resistance and vertical force transmission, which has a great impact on the structural cost. In this study the design of core tube structure in typical super-tall buildings is investigated by using intelligent optimization algorithm. First, a number of engineering cases of super high-rise buildings around 300m high are collected, the common parameters for super-tall structure are summarized, and a typical super-tall building structure model is established accordingly. The advantages and disadvantages of each optimization algorithm are briefly analyzed, and the computational efficiency is compared. Then, the design process of the core tube combined with the intelligent optimization algorithm is proposed, the mathematical model of constraint optimization is established, and the constraint conditions related to the specification and construction are introduced into the optimization process using the penalty function method. Finally, the method is used to optimize the wall thickness of the core tube with different outer frame stiffness and different coupling beam height, and the distribution law of the wall thickness after optimization under different conditions is provided.

Based on the pulsation method, the dynamic characteristics of a column-less steel spiral stair were tested, and the natural frequency and damping ratio of the steel stairs were obtained. Based on the test results, a numerical model was established to study the comfort and influencing factors of the column-less steel spiral stairs. The research results show that the comfort of the steel stair meets the requirements of the current Chinese design code. Change of the constraint conditions at the end of steel stairs and adjusting the stiffness of arc beams supporting them can significantly impact the comfort of column-less steel spiral stairs.In addition, in order to facilitate the design, based on the above analysis, an approximate calculation formula for the natural vibration frequency of the column-less steel spiral stairs was proposed, which can be used to estimate the natural vibration frequency of such steel stairs and predict the comfort level in the preliminary design stage. It provided some reference for the design and comfort analysis of similar stairs in future.

The total length of the Changchun indoor ski resort is about 443.4 m, which is divided into two structural units through the seismic joint.The length of the high-zone unit is 231 m, and the low-zone unit is 211 m.The width gradually changes from the straight section of 64.8 m to the widest section of 131 m and then decreases.The building adopts frame-shear wall system, and the roof of long-span pipe truss is supported by tall frame column above the ski run.The two independent structural units of the project are both out-of-code high-rise buildings, which have irregular torsion, low inter-story stiffness ratio, tower offset, inclined column, staggered floors, vertical dimension sudden change and so on.This paper introduces the macroscopic system optimization method of this kind of structure, as well as the analysis of the important and difficult points in the design of superstructure, such as the specific and reasonable arrangement of the lateral force resistance system of the structure, the type selection of special components such as large side columns, straddle columns, inclined columns, roof system, etc., and the key points of the analysis of temperature stress of ultra-long structures.The determination and analysis methods of seismic performance targets ensure the rationality and reliability of the superstructure system, components and joint forms.

The layout scheme of guyed pole waist ring cable has an important influence on the efficiency and safety of UHV transmission tower erection construction. In order to study and obtain an economical, reasonable, safe and reliable layout scheme of holding pole waist ring cable, according to the real size of GGTY2 × 7t / 16-1000 type landing electric rotating double flat arm holding pole, this paper uses the finite element analysis method to establish the holding pole-waist ring-cable coupling mechanical analysis model under the condition of UHV transmission tower assembly. The mechanical characteristics of holding pole and cable under different working conditions and different typical waist ring cable layout schemes are calculated. Through the analysis of the displacement of holding pole and the tension of cable, the optimal arrangement scheme of holding pole waist ring cable is obtained. The coupling calculation method and analysis conclusion of pole-waist-strut coupling obtained in this paper can provide technical support for UHV transmission tower assembly and improve the efficiency and safety of construction assembly.

For steel-normal concrete （NC）-UHPC composite slabs, part of the concrete is replaced with UHPC, which can improve bending performance and durability of steel-concrete composite slabs. Since the use of UHPC decreases the thickness of composite bridge slabs, the punching shear failure might occur under heavy load. Therefore,it is necessary to conduct studies on punching shear performance of steel-concrete-UHPC composite slabs. The punching shear test of five composite slabs was completed in the paper. The punching shear effects of the thickness of UHPC layer, the loading area and the aspect ratio of the loading area are analyzed and compared with experiments. And the punching shear failure modes are analyzed and the calculation methods of punching shear bearing capacity are proposed based on plastic theory. The research results show that UHPC layer can significantly improve the bearing capacity and ductility of the composite slab. And the bearing capacity of the composite slab increases with the thickness of the UHPC layer and the loading area. The theoretical calculation results of punching shear bearing capacity are consistent with test results.

Ground motion spectral shape characteristics have a great importance to analysis of the seismic fragility of reinforced concrete frames. The incremental dynamic analysis （IDA） on a five-story reinforced concrete frame structure is carried out using 9 groups of ground motions which take into account the different parameters. Using the IDA, the seismic fragility curves corresponding to different damage states and collapse margin ratios （CMRs） are obtained based on the maximum inter-story drift ratio （θ_max）, the average values and dispersion of the maximum residual inter-story drift ratio （RIDR_max） corresponding to the 50% exceeding probability with different damage states and the limit of performance index of RIDR_max corresponding to different seismic performance grades are proposed. The results show that the conditional mean spectrum （CMS） of different spectral shape parameters （ε）, magnitude （M） and earthquake distance （R） significantly influence structure seismic fragility analysis; the ε, M and R have a significant influence on RIDR_max of the structure when the damage is small, but the effect will be no longer obvious when the damage is greater.

Saline frozen soil is widely distributed in southern Xinjiang, and the severe temperature difference and freeze-thaw alternation make the soil body prone to salt frost heave deformation, especially the high groundwater table in the oasis and edge zone of Yanqi Basin, so that salt swelling, frost heave, thaw sinking, pulp turning and other diseases occur in the saline soil roadbed. In order to simulate the salt migration and salt crystallisation law of salinized permafrost roadbed in Yanqi Basin under the condition of high water table and high mineralisation, this paper established a model of salinized permafrost roadbed under open conditions by combining the ground temperature and soil layer measurement data of the highway project of 21-24 corps of the Second Agricultural Division in the relevant Yanqi Basin, and verified the reasonableness of the temperature field of roadbed through the measured data of roadbed temperature. On this basis, the water salt migration and aggregation law and salt crystallisation of sulphate salted soil and the water salt migration and aggregation law of chloride salted soil were analysed under open conditions, and the results of the study showed that： the increase of salt concentration only retarded the process of changing the temperature field of the roadbed, and had a small influence on the final distribution; the maximum difference in the location of the water salt aggregation of sodium chloride salts was about 0.4 m; and the higher the initial water content of the foundation was, the faster the water salt migration was.