Due to the increasing requirements in seismic design codes and the performance deterioration of structures during the long-term service, seismic performance of existing buildings will no longer meet the design requirements. It is imperative to conduct seismic retrofit design. However, the current retrofit design method usually needs a large number of repeated iterations of nonlinear dynamic calculation, increasing the design difficulty and reducing its applicability. A performance-based seismic retrofit design method is proposed for the existing buildings based on energy balance, which is applicable for structural retrofitting with energy dissipation devices. It considers the performance target of multiple seismic levels without nonlinear dynamic calculation and few iterations during the design. A benchmark steel frame is retrofitted by the proposed method, and nonlinear dynamic analysis is performed to evaluate the performance of the original and retrofitted structures. The results show that the drift ratio of all floors is significantly reduced after retrofitting, and the average decreases for service level earthquake (SLE), design basis earthquake （DBE） and the maximum considered earthquake （MCE） are about 20%, indicating that the seismic performance is significantly improved by retrofitting. The inter-story drift ratios of the retrofitted structure under SLE, DBE and MCE are consistent with the design values, illustrating that the expected inter-story and roof drift ratio targets are achieved, which verifies the effectiveness of the proposed method. The damper designed by the proposed method remains elastic state overall during frequent earthquakes, and enters yielding state during DBE and MCE, realizing the expected energy dissipation mechanism. The ductility demand of the damper is evenly distributed along the height, which further indicates the rationality of the design method. The presented research can provide important reference to the seismic retrofitting design of the existing building structures.

The floor acceleration amplification (FAA) reflects the amplification effect of the main structure on the ground acceleration, but the current specification and research mostly rely on historical floor records or finite element analysis results. When complex building structures are involved, the results of calculation analysis and actual earthquake damage are often different. Based on the recorded data of the shaking table test of the scaled model of the integral structure, the FAA distribution of prototype structures along the height are obtained by fitting analysis. Using the shape model of quasi seismic response spectrum, the FAA distribution surface with a certain guarantee rate is obtained, and the corresponding calculation formulas for different structural types are proposed respectively. It can better reflect the FAA distribution characteristics of complex building structures compared with the specification. Finally, the influence of site predominant period change on FAA distribution characteristics of this type of building structure is qualitatively explored.

Resilience evaluation of infrastructure system provides an essential basis for the resilience enhancement and disaster mitigation of urban communities. This study presents a seismic resilience evaluation model for water supply network that integrates the hydraulic with water quality simulation. The seismic damage scenarios of water supply network are generated according to seismic fragility model of pipelines and the Monte Carlo simulation, and the post-earthquake recovery of pipeline damages is simulated by dynamic importance-based recovery sequence. The negative influence of earthquake hazard on water quality is investigated by the chlorine concentration reduction of water, which depends on the changes in water age and supply path caused by pipeline damages. The water supply of user nodes without quality deterioration after earthquakes is used as the water quality performance index of water supply network. The proposed evaluation model is implemented in two benchmark water supply network with different layouts. Application results show that the water losses of pipeline damages lead to water flow increases and greater chlorine concentration in its upstream pipelines, and lead to prolonged water supply path and smaller chlorine concentration in its downstream pipelines. The water quality resilience of water supply network tends to be lower than that of hydraulic services, and the relative difference between hydraulic and water quality resilience is affected by the layout and operating rules of water supply network. In the application case of water supply network, the relative difference of seismic resilience loss calculated by water quality and hydraulic ranges from 17% to 286%, and there is a large difference between hydraulic and water quality resilience of water supply network whose operating rules are complex and contain regulating tanks.

The seismic reliability of water supply networks refers to its capacity to satisfy water demands of customers in the presence of potential seismic events. Currently, the majority of seismic reliability assessments for water supply networks employ Monte Carlo simulations to generate numerous seismic damage samples for evaluation. However, this approach becomes highly demanding in terms of labor and time when assessing extensive and intricate networks. To address these challenges, the equivalent scenario method is proposed as a means to enhance computational efficiency. The proposed method involves the generation of posterior probabilities using seismic damage scenarios. Subsequently, these probabilities are employed to generate equivalent scenarios. Finally, the equivalent scenarios are utilized to determine both the node reliability index and the system reliability index. The simulation results obtained using the proposed algorithm are then compared with those obtained using the traditional Monte Carlo method.The results demonstrate the feasibility of generating equivalent scenarios based on posterior probabilities. Specifically, when evaluating the reliability of 100 equivalent scenarios at a seismic intensity of 8 degrees, a few nodes exhibit evaluation errors exceed 10%, while the evaluation errors for the remaining nodes at lower seismic intensities are below 5%. Additionally, the evaluation errors for small seismic intensities are all below 5%. Moreover, increasing the number of equivalent scenarios from 100 to 250 can further reduce the assessment error to less than 5%. Thus, the algorithm proposed in this paper ensures accurate results while enhancing computational efficiency.

A structural damage recognition framework based on a self-training semi-supervised neural network (SSNN) is proposed to solve the problem of insufficient labeled data in structural damage identification. The framework utilizes the multilayer perceptron (MLP) neural network for semi-supervised training by the self-training method. The data samples with high confidence are selected from the unlabeled data to make pseudo labels, expanding the training set. Normalized frequency change ratio and damage signature index are employed as input features of neural networks to identify structural damage. Firstly, the theory fundamentals of semi-supervised self-training learning are introduced. Secondly, the procedure of structural damage identification based on self-training semi-supervised learning, including neural network construction, damage characteristic extraction, and classifier evaluation, is introduced. Finally, the proposed damage identification method is illustrated by numerical simulation of a spatial truss and experimental data of a three-story frame. The results show that the self-training semi-supervised method can expand the labeled sample data by selecting samples with higher confidence from unlabeled data, thus providing sufficient labeled data for damage identification. Under the insufficient labeled data conditions, the SSNN performs better than MLP. Compared with MLP, SSNN increases the identification accuracy by 4% and 9% under the single and two positions damage locations, respectively.

In order to improve the structural damage identification effect based on vibration signal, a structural damage identification method based on the combination of correlation function and convolutional neural network is proposed. Taking a railway steel girder bridge structure as an example, firstly, the signal-to-noise ratio of the vibration signal is improved by performing autocorrelation calculation on the vibration response of the structure, then the autocorrelation sample is used as the input of convolutional neural network, which can significantly improve the recognition accuracy. When the noise level in the vibration signal is higher, the improvement effect of the recognition accuracy of the autocorrelation sample as the convolutional neural network input is more obvious, and the autocorrelation operation has stronger noise immunity than that of the fast Fourier transform. The cross-correlation function is used to fuse the data of the multi-sensors arranged on the structure, then the fused signal is used as the input of the convolutional neural network. Under the premise of effective fusion of the data characteristics of the two sensors, the cross-correlation can double the dimension of the data set and reduce the number of parameters of the network operation, thereby reducing the time and improving the training efficiency, and the cross-correlation sample as the network input also has high recognition accuracy and strong noise immunity.

To identify structural damage efficiently and accurately, a hierarchical identification method of structural damage based on structural dynamic characteristics and deep belief network is proposed by combining machine learning with intelligent algorithm, and the damage position and degree are identified in turn. In order to identify the damage location, a 6-element vector is established by using the first three vertical vibration frequencies of the structure and the third modal displacement of a single node, and the damage location is identified by using the 6-element vector as input parameters. To identify the damage degree, the first three natural frequencies and modal displacements of vertical vibration or the 6 nodes modal curvature differences are used as parameters to input the depth confidence network to identify the damage degree. A simple-supported beam is taken as a model to verify it. It is shown that the damage position recognition accuracy can reach 100% even if the noise level reaches 10%. When identifying the damage degree, the deep belief network based on six-node modal curvature difference has strong noise resistance. The maximum relative error of damage degree prediction is less than 5.08% and the mean square error is 0.4878 under the noise of 15%. Compared with BP neural network, the prediction ability of BP neural network is better than that of deep belief network when there is no noise. Under the same noise level, the prediction ability of depth belief network is obviously better than that of BP neural network, which shows that the hierarchical identification method of structural damage based on structural dynamic characteristics and deep belief networks has strong robustness and high accuracy of identification results.

In order to get rid of the problems of inaccurate instantaneous frequency (IF) estimation and energy dissipation inside the local maximum synchrosqueezing transform algorithm, an improved method is proposed and named as local maximum synchrosqueezing transform (ILMSST). Firstly, multiple iterations are performed on the obtained IF positions to get more precise IF positions. Secondly, the IF positions where maximum values of STFT coefficients appear are searched and then moved up and down to pre-estimate IF bands. After that, the STFT coefficients outside the pre-determined IF bands are totally assigned to zero. Finally, the IF positions that correspond to local maximum values of STFT coefficients are found out and subsequently an operation of reassignment is performed on the obtained IF positions to get refined IF bands. To verify the effectiveness of the proposed method, two numerical cases and two tests on a seven-story reinforced concrete shear wall structure and a steel cable with time-varying tension forces are investigated. The results demonstrate that the proposed ILMSST method behaves better than current local maximum synchrosqueezing transform. Moreover, it not only enhances the accuracy of IF estimation but also improves time-frequency energy concentration.

Due to the problem that the tuned mass damper (TMD) system is easy to be off-tuned when applied to light structures, which leads to the decline of vibration reduction effect, a new shape memory alloy semi-active TMD system is designed in this paper. The system uses steel cables to suspend the mass to bear all its weight. Large shape memory alloy bars with rectangular effective cross sections are used to provide different bending stiffness in the two directions of the TMD system in the horizontal plane. In order to study the semi-active performance of the system, a full-scale shape memory alloy TMD system was subjected to free vibration tests in this paper. By changing the working temperature of the shape memory alloy, the influence of temperature change on the frequency and damping ratio of the TMD system was studied. The test results show that by controlling the working temperature of the shape memory alloy from -40 ℃ to 80 ℃, the frequency of the TMD system shows an increasing trend with temperature increases, while the damping ratio shows a decreasing trend with the temperature increases. The results show that the new shape memory alloy semi-active TMD system is applied to controlled structures, and once the TMD is off-tuned, it can be re-tuned by changing the temperature of the shape memory alloy. Therefore, the new shape memory alloy TMD system designed in this paper has certain engineering application value and prospect for the study of light structure vibration reduction.

Aiming at the demand of seismic protection of free-standing objects, a pendulum isolation device based on universal balls was developed. The structural characteristics and operation principle were introduced, and the design of an isolation device for protecting a pagoda could serve as a case study. Then the finite element software was used to analyze the bearing capacity between the universal ball and the disc. The accuracy of the damping mechanism analysis model was verified by tests. The isolation effect of the device under the eight-degree extremely rare earthquakes was analyzed by time history method, and was compared with the traditional friction pendulum. The results show that the isolation device not only has simple structure and reliable performance, but also has the characteristics of low friction coefficient, small acceleration threshold for triggering slip and flexibly adjustable damping mechanism. The carrying capacity of the node-to-surface contact can meet the design requirement. By means of viscous damper at one end, the damping mechanism shows obvious velocity correlation, and damping force increases with the increase of velocity. The device can achieve the isolation target while satisfying the displacement limit. Compared with the traditional type, when the displacement and acceleration response are limited, the device can achieve better comprehensive isolation effect under various seismic conditions by reasonably adjusting parameters of the damping mechanism.

With the development of wind power resource advantageous areas gradually saturated, the focus of wind power development has shifts to low wind speed areas with relatively poor wind resource conditions. Distributed, high power, high tower and long blades have become the trend in the wind power industry. Based on the above, a new rectangular concrete filled steel tube bundle wind turbine tower is proposed. The tower is made of rectangular concrete filled steel tube bundles, which has the advantages of high strength, rigidity and energy consumption capacity. To study the wind vibration response characteristics of this tower structure, the Kaimal pulsating wind speed power spectrum was chosen and the wind load time curve was simulated using the harmonic synthesis method to carry out the dynamic time analysis. Wind vibration coefficients and equivalent static wind loads were calculated for the tower. The results show that the maximum displacement of the top of this new tower at rated wind speed is 911.84 mm, which corresponds to a horizontal displacement angle of 1/154 and meets the code requirements. The tower components are of good strength and have a large safety margin. The wind vibration coefficient obtained by the displacement-equivalent gust load factor method is lower. Under the equivalent static wind loads calculated by the inertial wind load method, the structural displacements and basal shear forces are basically the same as those obtained from the structural random vibration analysis.

Flexural performance tests on 11 beams of full-scale reinforced concrete (RC) with HRB635 high-strength reinforcement were carried out to investigate their damage mechanism, failure mode as well as strength and ductility. The feasibility of the Chinese code formulae for calculating the ultimate flexural load bearing capacity and the maximum crack width of flexural components was also assessed for RC beams with high-strength reinforcement. The results indicate that the mechanical behavior and damage mechanism of the RC beams with HRB635 high-strength reinforcement are basically identical to those of RC beams with common reinforcement. The tensile high-strength reinforcements yielded first, then the compressive concrete crushed, and the tensile strength of the high-strength reinforcements can be fully utilized. The ultimate flexural moments of the test specimens calculated by the Chinese code were close to those of the test values, indicating that the flexural load bearing capacity of the beams with high-strength reinforcement can still be calculated according to the current Chinese code. The tested maximum crack widths of the specimens under serviceability limit state all exceeded the limit value of flexural structural components under short-term load, indicating that the design of RC beams with high-strength reinforcements may be controlled by the serviceability limit state rather than ultimate limit state. The calculated maximum crack widths were close to the tested ones, while the calculated results were slightly larger.

An innovative amalgamation of the very short shear link (VSSL) and shear slotted bolted connection (SSBC), referred to as the VSSL-SSBC, ingeniously enhances the ductility and energy dissipation capacity of the VSSL, resulting in minimal damage. Consequently, the seismic resilience of eccentrically braced frames is markedly augmented. Cyclic loading tests were carried on a VSSL specimen, three VSSL-SSBC specimens with friction slip and a VSSL-SSBC specimen with ultimate deformation respectively, so the failure modes, hysteretic curves, bond curves and mechanical curves can be investigated. The experimental findings indicate that the mechanical property of the VSSL-SSBC exhibits a bifurcated developmental trajectory, characterized by initial stages involving friction slip within the SSBC and subsequent severe damage within the VSSL. Moreover, the ultimate bearing capacity and failure mechanisms of the VSSL-SSBC are observed to be congruent with those of the standalone VSSL. As for the mechanical curves, the VSSL exhibits distinct stages, encompassing elastic, elastic-plastic, and failure phases. In contrast, the SSBC is characterized by an initial elastic and subsequent slip phase. The VSSL-SSBC, a hybrid configuration, undergoes an extended sequence of elastic, slip, elastic-plastic, and failure stages. Notably, the deformation and damage of the VSSL within the VSSL-SSBC are significantly mitigated at equivalent displacements when compared to the standalone VSSL.Ultimately, the utilization of the finite element method (FEM) has been employed to corroborate the hysteretic curve and failure mechanisms with specimen VSSL-SSBC. The findings from the FEM simulations demonstrate a high degree of concordance with the experimental data.

The socket connection is convenient in construction and has a large tolerance error, but the durability is poor. In order to improve the construction quality and optimize the durability, we proposed a new type of assembled bridge pier tenon-socket prefabricated bridge per by combining the wet joint connection technology of ultra-high performance concrete (UHPC). One tenon-socket prefabricated bridge per specimen and one comparative pier specimen (integral cast-in-place bridge pier) were designed and fabricated. The damage mechanism and seismic performance of the assembled specimens were studied by using the proposed static test method combined with numerical simulation. The test results show that: the damage of both specimens is mainly ductile damage in the form of bending damage, mainly manifested by a large amount of concrete crushing and spalling in the plastic hinge area at the bottom of the pier, while the damage of the assembled joint and grout is smaller, and the residual deformation of the assembled specimen is only 79.09% of the overall cast-in-place specimen when the ultimate load is reached, indicating that UHPC grout can enhance the damage tolerance of the pier and make it easier to repair after earthquakes. The tenon-socket prefabricated specimens with short socket depth and lap length of reinforcement achieve reliable connection, and exhibit bearing capacity, ductility, energy dissipation capacity and stiffness close to those of cast-in-place piers under the same hysteretic displacement. With socket depth of 0.4D(D is the width of the specimen section) and above, the joints are reliably connected, and the integrity and seismic performance are basically equivalent to those of cast-in-place. Increasing the modulus of elasticity of grout has an improvement effect on the stiffness of piers. The influence of longitudinal reinforcement diameter on the seismic performance of bridge piers is more significant than that of lap reinforcement in the abutment. Increasing the reinforcement rate of longitudinal reinforcement improves the horizontal bearing capacity and energy dissipation capacity more obviously, but increases the residual deformation of bridge piers.

To investigate the vibration comfort level of reinforced truss composite slabs applied in residential building floors, the vibration response of the integral connection reinforced truss composite slabs under human-induced excitation loads was studied through experiments. Three types of loading excitations, including single-person walking, three-person asynchronous walking, and three-person synchronous walking, were designed for experiments. For the single-person walking load experiment, three different walking paths including longitudinal, transverse, and diagonal were designed. The vibration response of the composite slabs under various human-induced excitations and walking paths was investigated. A refined finite element model of the composite slabs was established to analyze the influence of the protective layer thickness at the plate bottom, truss height, density ratio and modulus ratio of concrete to reinforcement on the natural frequency of vibration of the composite slabs. The results show that the peak acceleration under human-induced excitation increases with the layer height. The peak accelerations under different human-induced loading conditions decrease in the following order: three-person synchronous walking, three-person asynchronous walking, and single-person walking, and the peak acceleration under single-person walking condition is independent of the walking path. The natural frequency of the composite slabs decreases with the increase of the thickness of the protective layer at the plate bottom, and reaches the maximum when the truss height is 80 mm. The natural frequency is inversely proportional to the concrete-to-reinforcement density ratio, and is directly proportional to the concrete-to-reinforcement modulus ratio.

In order to solve the rail corrugation in the curve section of steel spring floating slab track in a metro, firstly, the characteristics of rail corrugation were tested on site. Secondly, according to the characteristics of rail corrugation, the precise tuning and development of wide-frequency tuned mass damper (WTMD) were carried out. Then, the parameters such as mass, stiffness and damping of WTMD were input to the established Vehicle-WTMD-Steel spring floating slab coupled dynamic model. The floating slab and foundation were considered as flexible bodies in the model. The wheel-rail contact was solved by the Kik-Piotrowski model, a multi-point non-Hertzian contact model. The 5th grade power spectral destiny formula from USA superimposed on the measured corrugation irregularity spectrum were used as excitation. The finite element software ANSYS and the multi-body dynamics simulation software UM were used to carry out the coupled dynamics analysis, and the WTMD parameters were optimized iteratively. At the same time, the rail vibration accelerations obtained by simulation analysis with or without WTMD were compared with the field measured data, and the influence of WTMD on rail vibration was studied. Finally, the total rail vibration level, track decay rate and three times corrugation tracking tests, with or without WTMD, were carried out to study the influence of WTMD on the rail vibration, the track decay rate and the corrugation development. The results show that: The first three dominant frequencies of the designed WTMD are 518 Hz, 700 Hz and 759 Hz, which are consistent with the vehicle passing frequency (520~830 Hz). The simulation and measured data are in good agreement, and the rail vertical vibration acceleration RMS is reduced from 200 g to 20 g after the installation of WTMD, and the vibration reduction effect is 8.1 dB. The WTMD can improve the vertical and lateral track decay rate and suppress the vertical and lateral rail pinned-pinned resonance. The three times corrugation tracking tests find that the rail corrugation develops slowly after the installation of WTMD, the rail corrugation is invisible.

In order to study the vibration response of saturated foundation caused by train moving load under irregular track conditions, and further improve the vibration propagation and attenuation law of saturated foundation, the track irregularity load is introduced into the saturated foundation 2.5D finite element in this paper. The track irregularity load is transformed into frequency domain-wave number domain through Fourier transform, and the vibration response caused by the quasi-static load is compared and analyzed. The results indicate that when the vehicle speed is low, the vibration difference caused by the following two conditions is very small. As the vehicle speed increases, track irregularity significantly increases the amplitude of acceleration and displacement of saturated foundation, and the time-history curves show stronger fluctuation. Track irregularity has little influence on the acceleration spectrum at the center of the track. When the train runs at low speed and high speed, the frequency spectrum rules of the two loads are basically the same, and the main frequency distribution is basically the same. Under the condition of track irregularity, only the acceleration in each frequency band increases slightly. In addition, the pore water pressure of saturated foundation caused by high-speed railway will be greatly increased by track irregularity, and the pore water pressure decreases rapidly with the increase of depth.

The pervious conditions of seabed sediments can directly affect their dynamic response characteristics during earthquakes, but most existing theoretical studies directly assume that the bottom of the sediments was an impermeable boundary. Therefore, based on Biot’s saturated porous media theory, through the analytical and semi-analytical solutions of the seabed transient response or steady-state response, the influence of the bottom water permeability conditions of the sedimentary layer on its dynamic response characteristics in earthquakes is studied. It is found that under the condition of bottom displacement excitation, fast wave or slow wave will generate the same type of compression wave when passing through the impermeable boundary of the sediment layer, and two types of compression waves will be generated when passing through the completely permeable boundary of the sediment layer. Even under the same excitation conditions, the vibration amplitudes of the two types of compression waves generated in the sediment layers with different permeabilities are significantly different. Permeable conditions at the bottom of the sediment layer also affect the frequency response characteristics of the seabed, and the displacement amplification coefficient of the bottom permeable sediment layer is large at low frequency. On the contrary, at high frequency, the displacement amplification coefficient of the bottom impermeable sediment layer is large.

Artificial boundaries are introduced to simulate the infinite domain in the analysis of soil-structure dynamic interaction, and the viscoelastic artificial boundary is one of the commonly used artificial boundaries. When the artificial boundary is used, the selection of the reference wave field as the input of seismic wave is very important, different reference wave field selection methods will lead to great differences in calculation accuracy. In this paper, four kinds of two-dimensional site models, including homogeneous half space, layered site, depressed terrain and underground structure are assumed. Then ANSYS finite element software and viscoelastic artificial boundary are used to simulate the above four site models considering SV wave vertical incidence and 30° oblique incidence. The calculation accuracy of three different reference wave fields is compared in detail. The results show that when the free wave field is selected as the reference wave field for all artificial boundaries of the soil-structure dynamic interaction calculation model, the accuracy of the calculation results is the highest.

The ground vibration input method based on viscous-spring boundary simulates the incidence of plane SV and P waves at different angles, and the acoustic structure coupling method is used to simulate the dynamic water pressure inside the lock chamber to study the seismic response of the lock roof displacement, acceleration and plastic damage in the ultra-high head lock chamber at different water depths. The study shows that when the seismic waves are obliquely incident, the seismic response of the ultra-high head locks varies significantly with the water depth compared to the vertical incidence, and the general degree of seismic response is greater than that of the vertical incidence. Under the same water depth conditions, the peak horizontal relative displacement and peak horizontal acceleration of the top of locks increases with the increases of the incidence angle in most cases. The seismic response of the lock chamber structure of the ultra-high head lock is significantly affected by the variation of the water depth. The area near the general gate wall with relative height of 0.2 is more likely to have serious damage, and when the relative water depth is 0.97, the tensile damage range on the waterfront side of the gate wall reaching serious damage is the largest. It is suggested that the combined effect of oblique incident seismic waves and different water depths within the gate should be considered.

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.