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.

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.

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 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.

In the reliability assessment and health monitoring of existing structures, beam deflection is not only a direct reflection of the normal service performance of structural members, but also a reflection of the safety status of structural members. Aiming at the safety control of structural members, this paper proved that the deflection to span ratio of beams is directly proportional to the maximum tensile strain and the comprehensive coefficient of deflection to span ratio. The comprehensive coefficient of the deflection-span ratio was validated using data from experimental references on the flexural performance of steel and timber beams. The synergistic effect of concrete floor slabs and steel beams affects the deflection to span ratio by increasing the height of the section, changing the height of the section neutral axis, sliding between the concrete wing slab and the steel beam, and changing the stiffness in negative moment area. The comprehensive influence coefficient is about 0.64~0.83. The synergistic effect of timber floors and timber beams has little effect on the deflection to span ratio, but wood creep causes a significant increase in the long-term deflection of timber beams. A beam deflection graded control method based on the maximum tensile strain limit was established. Compared with the deflection limit value in current standards, the results show that the deflection limits proposed in this paper has a clear safety control target, and is significantly different according to the change of the specific force characteristics of the beams. The range of the deflection limit is wider, more adaptable and more accurate than the current standard, and can be used as a reference for reliability identification and structural health monitoring of existing structures.

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.

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.

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.

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.

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.

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.

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.

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 self-tapping nails connecting construction for prefabricated composite shear wall was proposed in this research. Three full-scale composite shear wall specimens were designed and tested by low cyclic experiment to study the seismic behavior of concrete composite shear wall with self-tapping nails connection. The shear span ratio of specimens was 1.39. The experimental variables included self-tapping nails connection, self-tapping nails and post-pouring belt connection, and L-shaped structural column. The failure modes, bearing capacity, hysteretic characteristic, stiffness degradation, energy consumption, and strain response were analyzed and discussed. The experimental results showed that the self-tapping nails connection had the advantages of good mechanical behavior and convenient installation. Compared with the specimen with self-tapping nails connection, the ultimate bearing capacity and initial stiffness of the specimen with self-tapping nails and post-pouring belt connection increased by 8.54% and 6.03%, respectively. Compared with the specimen without L-shaped structural column, the ultimate bearing capacity, initial stiffness and energy consumption of the specimen with L-shaped structural column increased by 67.48%, 129.33%, and 277.93%, respectively. The concrete composite shear wall with self-tapping nail connection has good seismic performance that meets the seismic design requirement of prefabricated concrete composite shear wall residence building and it can be used in practice.

The precast concrete structures retrofitting with elevators using through-hole grouting connection can be widely applied to the elevator addition project of existing multi-story residential buildings. This paper introduces the system composition, construction process and key dimensions of this structure, including typical elevator shaft dimensions, minimum thickness of shear walls, and overhang length of connecting corridor. It discusses various dismantling options of the precast structure and the selection of lifting equipment,and reviews the design basis of the specific structure. The overall force performance of the structure is discussed in detail through the performance index of the structural model and the nonlinear dynamic analysis under severe earthquakes. Special attention is given to important and difficult structural design issues, such as the influence of the eccentricity of the overhanging connecting corridor, the design of vertical through-length reinforcement in the through-hole, the performance design of the positive section of the elevator shaft on the ground floor, and the shear strength of the horizontal construction joint on the grouted splice surface of the shaft on the ground floor. An economic comparison with the steel frame elevator structure shows that the precast concrete structure has safety, economy and durability and meets the construction requirements of green buildings. With the launch of large-scale products, the project of retrofitting elevators to existing residences will gradually realize alternative upgrades.

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 seismic fatigue performances of viscoelastic dampers （VEDs） are needed to be tested in production and application. The test methods of seismic fatigue performances for VEDs are specified in the current national standards for energy dissipation dampers. In this paper, the test loading protocols and the performance evaluation methods in present standards are summarized and compared, and based on this, four kinds of VEDs were tested and their mechanical parameters were analyzed. The results show that, based on different standards, variation rates for each mechanical parameter are different, and the conclusions whether the 15% limit is satisfied are also inconsistent.

A concrete frame （truss） ribbed wall filled with foam concrete was developed and the self-tapping nail connection between the T-shaped column and the ribbed wall was proposed. Two full-scale T-shaped column concrete ribbed wall with self-tapping nails connection specimens were designed and fabricated, included a cross-shaped frame rib wall specimen and a central bearing truss rib wall specimen. Low cyclic loading test was carried out to study the failure modes and hysteretic characteristics. The effects of different rib structures on bearing capacity, stiffness, deformation capacity and energy dissipation were analyzed. The results showed that the shear cracking of foamed concrete and the hardened mortar layer occurred in the cross-shaped frame rib wall specimens, and the failure characteristics of central bearing truss rib wall were the concrete cracking and steel bar fractured. Compared with the ribbed wall specimen, the bearing capacity and initial stiffness of the ribbed truss wall specimen increased by 4.3% and 69.0%, respectively. The displacement capacity and energy dissipation of the ribbed wall specimen was better than central bearing truss rib wall. The self-tapping nails connecting had good connection behavior, which ensured the coordinated deformation of T-shaped column and concrete ribbed wall. This research can provide reference for engineering design and construction.

In order to study the life cycle carbon emission differences of different steel structure schemes for fabricated building, modular steel structure and pure steel frame structure schemes are designed respectively for a practical project, and the life cycle carbon emissions of the two schemes are analyzed quantitatively based on the theory of life cycle assessment. It is found that the total carbon emission of the steel modular structure scheme is 10.61% higher than that of the pure frame structure of the same scale. The operation and building material production periods account for the largest two proportions of the carbon emissions of the two structure schemes, which reach 73.33% and 81.11% respectively. The recycling of the modules and high efficiency of construction of the modular steel structure scheme can effectively reduce carbon emissions. Finally, the carbon reduction strategies of steel structure buildings are put forward to provide references for low-carbon building designs.

In the study of the structural design and dynamic characteristics of transmission tower structures, the accurate determination of the tower's dynamic response through theoretical analysis and numerical simulation poses a significant challenge. This paper focuses on the ±800 kV Ultra-High Voltage Direct Current （UHVDC） transmission line towers and establishes a finite element model of the tower-line-foundation system. The p-y curve method is employed to represent the discrete nonlinear springs simulating soil-structure interaction. Different computational models, including single-tower, three-tower two-line, and the tower-line-foundation system, are compared and analyzed concerning the dynamic characteristics of UHV transmission towers. The study investigates the effects of the mass and stiffness of the transmission line on the tower's dynamic behavior, emphasizing the importance of considering tower-line coupling. The inclusion of pile-soil interaction results in a reduction in the natural frequency of the transmission tower. The tower-line-foundation system model yields frequencies that are relatively smaller compared to the single-tower model, and they are closer to the frequencies observed in field tests, validating the rationality of the tower-line-foundation system model.

This paper introduces a method for analyzing bridge accidents caused by non-natural disasters using Bayesian networks. Accident samples from domestic bridges experiencing non-natural disaster-related accidents during their operational phase were collected and subjected to statistical analysis and preprocessing of their indicators. Preprocessed statistical indicators were used as nodes to establish a Bayesian network model for bridge accidents under non-natural disasters. The model was validated, and through this model, posterior probabilities and sensitivities of various root nodes were inferred, analyzing the impact of various root node factors on the overall bridge damage. Correlations between bridge accident causes were calculated. The research results indicate that the age of the bridge's service has the most significant impact on the overall bridge damage. Factors such as the length of bridge, the construction year of the bridge, whether it is a beam bridge, and factors related to engineering quality, overloading, and collisions with vehicles and ships also influence overall bridge damage. Additionally, the effect of factors such as whether the bridge is made of concrete, is a single-span bridge, crosses water, is a highway bridge, and other causes related to accidents is relatively small and can be disregarded. There is a negative correlation between various bridge accident causes, with particularly high negative correlations between overloading and collisions with vehicles and ships, overloading and engineering quality, and collisions with vehicles and ships and engineering quality. The negative correlations between engineering quality and other causes, overloading and other causes, and collisions with vehicles and ships and other causes are relatively low.

In single-layer reticulated shell structures, rectangular steel tubes have advantages over circular and square steel tubes in terms of structural rationality and the utilization of material properties due to the presence of strong and weak axis. Firstly, the stability of four shell surfaces under internal and external biaxial compression bending is compared and analysed. These four shell surfaces are composed of four types of steel tubes independently, which are circular steel tubes, H-shaped tubes, square steel tubes, and rectangular steel tubes. Then, the rectangular steel tube is used into the finite element model of the spring element of the prefabricated joint, and compared with the rigid joint model to study the influence of parameters such as the effects of joint region, joint stiffness, initial defect amplitude, and span-to-depth ratio on the stable bearing capacity of the structure. The results show that the stable stress of the rectangular steel tubes can be balanced in both directions, and the stable stress in the strong axis direction is lower than that of circular and square steel tubes with the same cross-sectional area. For members with strong and weak axes in the cross-section and full utilization of materials in both directions, the influence of the flexural stiffness in the weak axis direction cannot be ignored.

After long-term service on a long-span suspension bridge, the cable force of some hangers can easily deviate from that of the completed bridge. However, the effect of the change in local hanger cable force on the bending moment of the whole main girder is unknown. In this paper,the Wuhan Yangluo Bridge is taken as the research object, and numerical analyses of a long-span suspension bridge are carried out. The validity of the finite element model is verified by comparing it with actual bridge test data. Based on the verified numerical model,a parametric analysis was carried out to study the effect of 10%, 15%, and 20% negative deviations of local single and three suspender cable forces （less than the cable force of the bridge） on the maximum bending moment of each beam section of the steel box girder. The results show that the negative deviation of single or three suspender cable forces is linearly related to the bending moment variation of a steel box girder. When the single suspender cable force has a 20% negative deviation from the bridge state, the bending moment of the steel box girder increases by 40% to 97%. When the cable force of the three suspenders has a negative deviation of 20% compared with the bridge state, the bending moment of the steel box girder increases by 195% to 445%.

The optimization design of steel frame-BRB structures is divided into two stages： the small seismic optimization stage and the large seismic adjustment stage. In the small seismic optimization stage, the objective is to minimize the cost, topological variables are used to represent the deployment positions of Buckling-Restrained Braces （BRBs）. The positions of BRBs, equivalent cross-sectional areas, and frame sections are used as design variables. Genetic algorithm is adopted to optimize the steel frame—BRB structure, while meeting the strength and stability constraints of the beam and column members, the BRB-non-yield constraint and the interlayer drift constraint; In the large seismic adjustment stage, the criterion method is used to adjust the components section of the structure which doesn’t meet the interlayer drift constraint under the large earthquake. This paper presents a comprehensive optimization design for steel frame-BRB structures, which greatly reduces the structural cost, and improves the economics of the structure while meeting the requirements of the code.

The construction details and working principle of viscous damper is introduced. Taking a kindergarten located in an 8-degree seismic fortification area as an example, five natural earthquake waves and two artificial earthquake waves are selected by using the Midas Gen finite element analysis software to analyze the dynamic response of the structure under frequent earthquake and rare earthquake, and the energy consumption of the viscous damper under the three-level earthquakes is given. The results indicate that with the addition of viscous damper, the main structure has good seismic performance and can achieve the "three-level" of seismic fortification goals. Under rare earthquakes, the overall plasticity of the structure is relatively low, and the damage yield mechanism is reasonable. Viscous damper exhibit good energy dissipation characteristics under earthquake action, providing a lower additional damping ratio under rare earthquakes than under frequent earthquakes,and the dispersion of additional damping ratios for multiple sets of seismic waves is also lower. This work can provide reference for similar projects.

Based on the OpenSees platform, a finite element model consisting of displacement-based beam-column elements and zero-length elements is developed for cyclic pushover analysis of columns, considering the plastic flexural deformation and bond-slip effect. The influence of the element length for the plastic region on the elastoplastic performance of columns is analyzed, and the reasonable element length is discussed. Finally, the numerical model is validated based on the quasi-static tests of three reinforced concrete cantilever columns with flexural failures in the PEER structural test database. The results show that the length of the displacement-based beam-column element in the plastic region has significant effects on the horizontal strength and displacement ductility of the column. The reasonable element length should be equal to the equivalent plastic hinge length, which can be calculated using the empirical formula proposed by Priestley et al.

The slab-column structure has been widely used in engineering with its advantages of simple force transmission path and flexible arrangement. However, it also has deficiencies such as easy to result in punching shear failure. The current research mainly focuses on the middle joints in the slab-column structure, and there is relatively little research on the side joints, but the performance of the side joints is also critical to the structural safety. In this paper, the finite element model of reinforced concrete hollow floor with steel concealed beam-concrete filled square steel tubular column edge joint is firstly proposed and compared with other scholars' test results to verify the accuracy of the finite element model. Based on this verified finite element model, parametric study including concrete floor thickness, concrete strength of floor, flange thickness of steel concealed beam are analyzed. The study shows that the parameter changes have different effects on the positive and negative moment zones. The increase of floor thickness, steel concealed beam flange thickness, strength and height can improve the flexural bearing capacity of the joint, but the too thick floor slab and the increase floor concrete strength will reduce the deformation capacity of the joints. As for the change of square steel tubular thickness and axial compression ratio, it will have little effect on the flexural performance of the joint.

The accuracy of traditional cable force testing methods for short suspension cables is unable to meet engineering requirements. This paper proposed the elasto-magneto-electric （EME） sensor with the magnetoelastic principle and magnetoelectric effect to complete the cable force monitoring of short suspenders, based on the suspension bridge load test of Qipanzhou Yangtze River Highway Bridge. The measurement results obtained from EME sensor were compared with the finite element analysis value and the measurement results from the traditional cable force sensor. The results show that experimental calibration error of EME sensor is less than ±2%, in the loading test, the measurement error of the traditional cable force sensor for the short suspender is relatively large, and the EME sensor can more accurately measure the increment of the cable force, which breaks through the difficulty of measuring the cable force of the short suspender. The results of the suspension cable force measurement with the EME sensor in the load test show that the deviation between the test value and the analysis value of cable force increment in field load test is less than ±5%, and the deviation between the actual cable force test value and its analysis value is less than ±4%.

The gas-ribbed inflatable membrane structure has the advantages of light weight, mobility and convenient construction, and has been widely used in temporary pavilions and hangars. In this paper, the structural forms of gas-ribbed inflatable membrane structure are analyzed through a literature review. Then, taking strip-cage type structure as the research object, the common node model is established to analyze the influences of diameter, number of braces, and internal pressure on the wind load effect of the structure. At the same time, the effects of various cables are clarified by deleting them from the model. Finally, the loading test of the inflatable arch is carried out, and the test results are compared with the results of the finite element calculation.