Jishishan earthquake caused serious damages to buildings in some areas of Gansu Province and Qinghai Province. The seismic damages of rural buildings at 11 survey points were investigated in areas with seismic intensities of 7 and 8 degrees. The seismic damage investigation shows that the earthquake disaster regions are mainly areas of towns and villages, and the main types of house structures are civil structure, brick and wood structure and unfortified brick concrete structure. In areas with intensity 8 degree, houses of civil structure mainly perform as severely damaged or collapsed. Brick wood structure and unfortified brick concrete structure houses were mainly damaged moderately and severely. Fortified brick concrete and reinforced concrete frame structure houses were damaged slightly and moderately. In areas with intensity 7 degree, civil structure houses were mainly damage moderately. Brick wood structure and unfortified brick concrete structure houses mainly damage slightly and moderately. Fortified brick concrete and reinforced concrete frame structure houses were mainly damaged slightly and basically intact. The seismic damage caused by the earthquake is more severe than that of earthquakes with the same magnitude, which is related to factors such as the amplification effect of ground-motion peak values of complex terrain in the earthquake area, poor quality of building masonry, and unreasonable structural stress of buildings. It is recommended to carry out further research on site amplification effect and spectrum impact of complex terrain, and attach importance to the earthquake resistance promotion and practical technology development of non-structural components of buildings.

A seismic damage investigation and analysis were conducted on the internal ceilings of public buildings in the 2023 M_s6.2 Jishishan earthquake. Three typical seismic damages, including the teaching building of Dahejia Middle School in Dahejia Town, Jishishan County, the outpatient building of Integrated Traditional Chinese and Western Medicine Hospital in Jishishan County, and the conference room of China Postal Bank in Jishishan County, were taken as examples to analyze the aluminum buckle plate ceilings that were less involved in previous investigations and study on typical seismic damage characteristics of aluminum buckle plate ceilings and indirect suspended ceilings, and some new seismic damage phenomena. Analysis suggests that aluminum buckle plates have sharp edges and corners, and the snap in connection requires a high level of flatness in the runner grid. If this type of ceiling is used in buildings with high seismic requirements or high personnel density, it is recommended to conduct specialized seismic analysis to avoid falling plates that may be harm to people or hinder their escape. In addition, in the assessment of seismic damage to suspended ceilings, in addition to the drop rate, factors such as deformation of the runner grid should also be considered. Furthermore, the reliability of the connection between the lighting units in the ceiling and the main structure should be strengthened to avoid a large number of falls during earthquakes. The analysis can provide reference for the seismic research and engineering application of suspended ceilings in public buildings.

This article mainly presents the investigation of bridges located in seismic intensity 8 degree and 7 degree zones on 306 Provincial Road, 310 National Road and Chuanting Highway. Peak acceleration of over 900 cm/s² was recorded at station GS. N0028 in the town of Dahejia, far exceeding the local rare earthquake fortification standard. However, the investigation results show that the bridges in the intensity 8 degree zone were mainly slightly damaged, including restrainer damage, lateral displacement of the main girder and bearing sliding, except for one bridge on Chuanting Highway where shear cracks were found in the pier, no other bridge in this area was found that suffered main structural damage. Bridges in the intensity 7 degree zone were basically intact, with some rubber deformations and unrecoverable displacements in the rubber bearings, as well as changes in the distance between restrainers. Fortunately, these issues did not affect their functionality. Concrete restrainer, as a measure to prevent lateral displacement of the main beam, has shown effectiveness in seismic damage, and is lack of rapid recovery characteristics. At the same time, the restrainer that installed cushion rubber pad also suffered severe damage, therefore, improving the cushioning device and considering the quick recovery of performance are needed in the future studies.

In order to solve the problem of input ground motion of fault-crossing structure and reveal its seismic response law, based on the physical model of the fault and the equivalent pulse function, this paper constructs a matrix considering the spatial variation characteristics of ground motion. A hybrid simulation method of high and low frequency superposition is proposed to simulate the input ground motion on both sides of the fault. Firstly, based on the established bridge site fault model, the stochastic finite-fault method is used to generate high-frequency ground motion at the target location. Secondly, according to the characteristics of pulse effect and permanent displacement of ground motion on both sides of the strike-slip fault, different equivalent pulse models are used to simulate the parallel and normal low-frequency pulse components of the fault respectively. The Butterworth filter is used for high-pass and low-pass filtering at the cut-off frequency. According to the drilling data, site model and the spatial coherence of ground motion on both sides of the strike-slip fault, a transformation matrix is established to simulate its spatial variability. Finally, the high and low frequency components after matched filtering are superimposed in time domain to obtain the input ground motion on both sides of the fault. The rationality of results is examined in three aspects including time history, response spectrum and structural response. 3D dynamic finite-element model of the actual fault-crossing suspension bridge is established using OpenSees to analyze the seismic response under the simulated ground motions. The results show that the angle and position of the fault-crossing and the amplitude of the permanent displacement have a significant influence on the seismic response of the fault-crossing bridge. The large residual internal force and residual displacement are the important reasons for the damage of the bridge.

In assembled integral shear wall structures, the quality of sleeve grouting connections is random, that the vertical connection performance of structure and the seismic performance of structure will be affected. According to the pull-out tests of grouting sleeves with different defective degrees, a set of equivalent grouting sleeve defective connection bearing capacity models is established in this paper, and a finite element model of the assembled integral shear wall structure is built based on an actual engineering structure. By considering the randomness of grouting defects, the mechanical connection properties of grouting sleeve joints are given to the corresponding degree of defects, reflecting possible defects in the grouting sleeve. Structural stochastic non-linear response analysis and reliability assessment were carried out by non-linear finite element analysis and combined with probability density evolution method(PDEM). The results show that the structural non-linearity has a significant coupling effect with randomness under dynamic action. The randomness of defects will gradually amplify the effect on the structural response over time, and there will be significant differences in the overall reliability of the structure in different safety domains.

To investigate the seismic performance of the monolithic precast concrete wall with concealed steel plate bracing, a two-story monolithic precast concrete wall with concealed steel plate bracing and a benchmark two-story cast-in-situ wall with the same bracing were designed and constructed. The bracings in the precast wall were connected by welded joints at the wall-to-wall and wall-to-foundation connections to fit the larger construction tolerance. Cyclic loading tests were conducted on the walls. The results indicated that the bracings in the precast wall connected by welded joints were able to satisfy the large construction tolerance requirement and transfer the internal force well. The seismic performance of the monolithic precast concrete wall was emulative to the cast-in-situ wall in terms of the lateral strength, stiffness degradation, and energy dissipation. Both of the walls were failed in flexure, but the monolithic precast wall formed an additional plastic zone at the top interface of the post-casting segment.

Assembly supports and hangers have been widely used in engineering, but there are few researches on their seismic performance. To investigate the failure mechanism, seismic behavior and influence factors of assembly portal supports and hangers under earthquakes, reverse cyclic loading were subjected to two different typologies of specimens to acquire the influence of seismic bracing and joint connectors on their seismic behavior. The results showed that specimens without seismic bracing were easy to fail at the right-angle or channel base connectors, specimens with seismic bracing were easy to fail at the connection of pipe hoop. The seismic performance of the joints connected by interlocking was poor, while the joints connected by bolt-through was superior. The elastic stiffness, ultimate strength, yield strength, strength and stiffness degradation, and energy dissipation of specimens with seismic bracing were better than those of the specimens without seismic bracing. The main reason affecting the seismic behavior of specimens without seismic bracing was the performance of joint connectors, while the main reason for specimens with seismic bracing was seismic connectors. The research can provide reference for the engineering application, quality inspection and standard formulation of supports and hangers.

In order to meet the needs of the rapid development of super high-rise buildings and modern industrialized residential building systems, a new type of plate-reinforced composite (PRC) coupling beam with steel bar truss deck is proposed. The failure mode, bearing capacity, deformation capacity and energy dissipation capacity of PRC coupling beams without considering the effect of floor slab, with ordinary reinforced concrete(RC) floor slab and with steel bar truss deck were studied by quasi-static test. At the same time, ABAQUS software was used to analyze the stress development of concrete, steel plate and steel skeleton of PRC coupling beam with steel bar truss deck under different peak loads. The results indicate that the shear bearing capacity and ductility of the coupling beam can be significantly improved with steel bar truss deck, and the setting of steel bar truss deck can significantly increase the peak load of the coupling beam, and the improvement of the bearing capacity of PRC coupling beam with steel bar truss deck is stronger than that with RC slab. The forward peak load of specimen PRC-S3 is 31% and 18% higher than that of PRC-NS1 and PRC-S2, respectively, but the stiffness degradation of the coupling beams with slabs were more serious after cracks were produced at the junction of beams and slabs. PRC coupling beams with steel bar truss deck have superior energy dissipation capacity, and there are significant diagonal compressive struts in the span of the coupling beams. The main compressive strut and its derivative compressive struts together constitute the truss to bear the shear force. Stress concentration occurs at the bottom of the coupling beam in the upper and lower chord reinforcement of the truss and the longitudinal reinforcement of the coupling beam, and the cumulative energy dissipation corresponding to the failure point of the coupling beam specimen PRC-S3 is 1.39 times that of the specimen PRC-NS1 without slab.

A recoverable precast shear wall composed of precast RC wall and steel energy-dissipator (RPSW-SE) was proposed and tested under reversed cyclic load. The failure process, shear capacity, hysteretic behavior and degradation characteristics were compared with that for cast-in-place concrete shear wall. Moreover, the damaged specimens were repaired by replacing damage steel member and tested again to investigate the seismic performance including hysteretic behavior, shear resistance as well as energy dissipation capacity, and to discuss the recoverable of RPSW-SE. The results showed that the RPSW-SE had good integrity and shear resistance, and the hysteretic curves were relatively full. The steel-energy connection area yielded prior to RC wall and dissipated a large amount of energy, enhancing the deformation capacity and energy dissipation capacity. The stress distribution and damage evolution of the shear wall was improved, and the failure of the RPSW-SE was caused by the fracture of the short steel-column at the slits of the shear-plate, without obvious plastic damage in the concrete wall. It was analyzed that more than 90% of the energy-dissipation in the shear wall was concentrated in the steel-energy connection area, achieving the controllable damage and energy dissipation. The performance indexes of the repaired RPSW-SE were close to those of original ones, indicating that the RPSW-SE had good recoverability.

The steel column-steel plate shear wall coupled structure(SC-SPSW) uses steel coupling beams to connect the steel plate shear wall and the steel columns on both sides. The system can make full use of the coupling effect between steel plate shear wall, coupling beams and steel columns to improve the shortcomings of traditional steel plate shear walls and have favourable seismic performance. This paper adopts plastic design based on energy concept, and derives the design method of SC-SPSW system by combining with relevant codes. Using SAP2000 software, twelve SC-SPSW system cases with different heights and coupling ratios(CR) were designed and carried out by static analysis and dynamic time history analysis to investigate the yielding mechanism and the influence of the coupling ratio on the seismic performance. It is shown that all SC-SPSW systems applying this design method can achieve the ideal yielding mechanism with excellent seismic performance. Suggestions are also made in terms of the appropriate selection of CR for different structural heights.