In order to quantitatively assess the effect of different infill wall construction methods on the seismic performance of reinforced concrete(RC) frames, domestic and foreign pseudo static test data of masonry infilled RC frames were collected, and a total of 68 specimens with detailed data in 19 literatures were selected as samples to analyze and compare the effects of three types of construction methods, namely, flexible connection of infill walls, integrity enhancement of infill walls, and installation of damping devices, on the strength, initial stiffness, ductility factor and equivalent viscous damping factors of the specimens. The results show that compared with the traditional construction methods, the strength and stiffness of specimens with flexible connection infill walls decrease, and the deformation capacity increases. The method of enhancing integrity can improve the strength, stiffness and deformation capacity, and it is a better method to reinforce the infill walls of existing buildings. The strength and stiffness of the structure with damping energy dissipation devices are reduced, but the deformation and energy dissipation capacity of the structure are improved, which can be used as a resilience improvement for new buildings if the construction cost is acceptable.

Viscous-spring artificial boundary is one of the effective means to solve the problem of dynamic soil-structure interaction, but it usually requires a lot of nonlinear dynamic time-history calculation in the process of analysis, and the efficiency is low. This paper aims to establish an efficient calculation method for solving the governing equations of dynamic soil-structure interaction problem with viscoelastic artificial boundary. Therefore, the efficiently inelasticity-separated solve idea is introduced to construct the nonlinear dynamic soil-structure interaction analysis model based on the inelasticity-separated finite element method and viscous-spring artificial boundary. The derived dynamic governing equation is basically same as the governing equation of the fixed boundary that only need to directly add the spring-damper stiffness of the viscous-spring artificial boundary into the initial stiffness matrix and damping matrix of the near-field soil-structure model. In addition, an improved Woodbury approximation method is proposed by combining Woodbury formula with the combined approximation approach, which can reduce the time and space complexity in solving governing equation, and realize the efficient solution of the dynamic governing equation of dynamic soil-structure interaction problem by using viscous-spring artificial boundary. The proposed method retains the advantages of viscous-spring artificial boundary and inelasticity-separated finite element method, and the correctness and efficiency are verified by a numerical example.

To address the limitations of curvature mode indicators in identifying minor structural damage, a method for structural damage identification that combines curvature mode and wavelet transform has been proposed. In this paper, ANSYS was used to establish a finite element model of the wooden beam before and after the damage and carry out modal analysis, and the curvature modes of the wooden beam before and after the damage was subjected to discrete wavelet transform to obtain the wavelet coefficient difference index. the damage location of the wooden beam was judged according to the peak of the wavelet coefficient difference mutation, and the damage degree of the wooden beam was estimated by fitting the relationship between the wavelet coefficient difference and the damage degree. The wooden beam test verified the index. The results show that the wavelet coefficient difference index can accurately identify the damaged location of wooden beams. The damage degree of wooden beams can be quantitatively estimated by fitting the relationship between the wavelet coefficient difference index and the damage degree. The research results provide a theoretical basis for wooden beam damage identification.

The 1970 Tonghai M_s7.7 earthquake is the strongest and the most intensity earthquake in Yunnan Province in the last 100 years. The Tonghai Basin experienced an abnormally high intensity ranging from IX to X degrees, resulting in severe damage. Based on data such as the thickness of the Neogene strata and shallow velocity structure of the basin, this study establishes a three-dimensional model that includes the 1970 Tonghai seismogenic fault and the Tonghai Basin. Multiple source models with asperities at different depths on the fault plane and the three-dimensional spectral element method are used to simulate the seismic ground motion of the Tonghai earthquake. By comparing the simulated distribution of peak ground velocity (PGV) with intensity and analyzing the strong motion distribution, as well as the generation of intensity anomaly zones, the reasons behind them are examined. The study indicates that the hammer-like distribution of the near-fault strong ground motion in Tonghai earthquake may be caused by the rupture directivity effect, and the mountain on the northeast side of the fault surface has a significant amplifying effect on the ground motion. The prominent amplification area in the Tonghai Basin is mainly located in the depressed area corresponding to the intensity anomaly zone of IX degree in the southwest of the basin. The PGV simulated by different source models in this area is significantly higher than that in other areas of the basin. The intensity anomaly zone simulated by the source model with asperities at depths of 10~16 km is significantly larger than that of the observed intensities, while the source models with asperities at depths of 2~8 km are relatively closer. The main cause of the intensity anomaly zone is the superposition of body waves and surface waves within the basin. The different depths of the asperities result in significant differences in the dominant frequency and amplification factor within the basin, with the shallowest asperities model causing amplification at the deepest part of the basin approximately twice of that of the deeper asperities model.

In offshore engineering, large-diameter steel pipe piles are often installed with hydraulic hammers. Accurate analysis of pile drivability is of great significance in practice. In order to study the relationship between cone tip resistance of cone penetration test(CPT) and unit of hammering energy, the resistance to energy ratio was defined as the ratio of unit of equivalent cone tip resistance to unit of hammering energy resistance by converting cone tip resistance into unit equivalent cone tip resistance. Based on 9 sites, 72 steel pipe piles driving records and CPT test results, the relationship of resistive energy ratio with depth in different soil layers (silt, sand and clay) was discussed, and a method based on CPT cone tip resistance was proposed. The results show that the variation of unit equivalent cone tip resistance with depth is consistent with that of unit of hammering energy with depth, but the change of resistance to energy ratio with depth in different soil layers are different. The relationship between the resistance energy ratio and depth in different soil layers was obtained, and it was possible to obtain the unit of hammering energy required for pile driving directly from the cone tip resistance of CPT. The method proposed in this paper is verified with an example in practice, and the results show that it is feasible. Because only the CPT cone tip resistance is needed to calculate the unit of hammering energy with the proposed method, it could be used to quickly evaluate the drivability of piles.

Study the influence of different seismic response control methods on the seismic performance of inter-story isolated multi-tower structure with a large chassis, identify the advantages of different methods in improving the seismic performance, and then provide reference for the seismic response control of such structures. Three control schemes were designed based on a real engineering practice of such building, including adding viscous fluid dampers in the isolation system, adding viscous fluid dampers in the large chassis, and increasing the stiffness of the large chassis. The elastic-plastic finite element models of three control schemes and the prototype structure were established by using the Perform-3D. The seismic responses of these four structures were analyzed and compared, and the control effects of three control schemes on the seismic responses were identified. The following conclusions are drawn that introducing viscous dampers to isolation system is an optimal scheme for controlling the displacement of isolation system and floor acceleration of large chassis, but it significantly increased the seismic responses of tower. The control effects of increasing the stiffness of large chassis on the inter-story drift ratio of large chassis, as well as on the inter-story drift ratio and floor acceleration of tower are the best. All three schemes have negligible control effects on the inter-story drift ratio of tower.

In order to better evaluate the T-shaped steel reinforced concrete(SRC) shear walls with the widespread application of steel reinforced concrete members deformation behavior, ABAQUS was used to study the failure morphology and deformation behavior of 324 T-shaped SRC shear wall designed according to specification. Based on to the collected test data, the failure mode of the members is analyzed, and the failure mode division criteria of T-shaped SRC shear wall is proposed. Based on the strain limit value of each material of the member, the component performance is judged, and the influence of axial compression ratio, shear span ratio, flexure shear ratio, steel ratio of the concealed column of the web, longitudinal reinforcement ratio of the concealed column and the characteristic value of the stirrup concealed column on the component deformation performance is considered. Through linear regression analysis of deformation limits and parameters in different performance states, the calculation formula of displacement angle limits in different performance states under different failure types is obtained. The failure probability of each performance state deformation limit is corrected according to ASCE 41, and the value table of each performance state deformation limit with 15%, 20% and 35% failure probability guarantee is obtained. The research shows that the shear span ratio and axial compression ratio have greate impact on component displacement angle limit of each performance state, while the steel ratio of the concealed column web, the longitudinal reinforcement ratio and the characteristic value of the stirrup have relatively small impact on the displacement angle limit of the member, but can improve its ductility. The limit value of displacement angle corrected according to ASCE 41 is reasonable and has certain safety reserves. It provides reference for performance-based seismic design and performance evaluation of T-shaped SRC shear wall.

In this paper, the method of partitioned analysis of soil-structure interaction (PASSI) is used to simulate the raft foundation-concrete frame model and pile foundation-concrete frame model in the shaking table test of nuclear island plant on soft soil foundation. The RG160, Chi-Chi and Landers seismic waves with amplitude modulation of 0.05 g, 0.10 g and 0.20 g were chose as input to the two models. Under various working conditions, the soil and structure acceleration amplification coefficient, floor response spectrum, time history of soil pressure at the bottom of raft foundation, pile strain and pile bending moment of shaking table test and numerical simulation test are compared and analyzed. The results show that: the numerical simulation results can reflect the shaking table test results well. After the amplification of soil layer, with the increase of floor, the coefficient of acceleration amplification increases in shaking table test and numerical simulation test, reflecting the same pattern. The response spectrum of soil-structure system obtained by shaking table test and numerical simulation is related to the frequency spectrum characteristics of input ground motion and the vibration characteristics of the system. In the shaking table test, the raft foundation will be overturned, and the time history of soil pressure at the bottom of the raft foundation shows the phenomenon of‘high in the east and low in the west’. However, this phenomenon does not appear in the time history of soil pressure at the bottom of the raft foundation in the numerical simulation. The reason is that the contact nonlinearity between the soil and the foundation is not considered in the numerical simulation. The seismic response of the pile group in the numerical simulation is basically consistent with the macroscopic phenomenon of the test, and there is a quantitative difference, which may be caused by the nonlinearity of the pile in the numerical simulation.

Earthquake damage to buildings always starts from a damaged component, so the importance analysis of building components helps identify the weakest component in the structure. Traditional researches often focused on structural components, and the importance of non-structural components was not well studied, resulting in the loss of non-structural components being much larger than the loss by structural components. In this paper, based on a large amount of detailed component earthquake loss data from the New Zealand earthquake, three importance analysis methods from random forest, namely the feature importance(FI), the permutation importance(PI) and the SHAP value(shap_values), were used to rank the importance of each component for earthquake losses. Assignment sort summation and normalized summation were used to assemble the results from the three methods representing the combined importance of each component. The normalized summation method can not only identify the relative importance of the components, but also quantify the significance of the differences among different components. The results demonstrate that of the 12 types of components analyzed, non-structural components are more important than structural components in earthquake loss contribution, and wall ornaments are the most important component, followed by slab foundations, but roof framing is the least influential. The results indicate that future earthquake resistance efforts should put more focus on wall ornaments and slab foundations.

In order to avoid the settlement of seismic isolation bearings caused by uneven foundation settlement and the hidden damage to the superstructure, a vibration signal identification model based on multi-input convolutional neural network (MI-CNN) is proposed to identify the settlement of seismic isolation bearings. First, the horizontal acceleration and displacement signals of seismic isolation bearings are collected, and the samples are expanded using normalised pre-processing and data enhancement methods. Then, the samples are fed into the established network model and trained. Finally, the settlement identification is performed using the trained network model. The results show that compared with the traditional single-input CNN model, the MI-CNN model is easier to train and can maximise the ability of CNN to extract features from the settlement signals, and it has a better accuracy in identifying the settlement location, a smaller error in identifying the settlement degree, and a more stable identification effect for the unbalanced data set. The results of this study can provide new ideas for the settlement identification of seismic isolation bearings.