Acceleration Amplification Factor Research Articles

Response and fragility of long-span truss structures in ultra-high voltage substation subjected to near-fault pulse-like and far-field ground motions

This study numerically investigates the seismic responses, bearing capacities, and fragilities of long-span truss structures (LSTSs) in ultra-high voltage substations subjected to near-fault pulse-like (NFP) and far-field (FF) earthquakes. The finite element model established in ABAQUS software considers the tower-line dynamic coupling effect, and it is excited by 20 NFP and 20 FF earthquakes. The seismic responses and bearing capacities are analyzed to generate the design recommendations for LSTS. According to five performance levels, the fragility curves are developed by performing a fragility method based on intensity measure. The peak displacement, acceleration amplification factor, bearing capacity, and fragility results significantly indicate that the seismic risk of LSTS under FF earthquakes is much higher than that under NFP earthquakes. Moreover, there are three typical failure modes (i.e., I – III) of LSTS under strong earthquakes. Mode I is a brittle failure while mode III is a ductile failure. Furthermore, the bearing capacity basically obeys a lognormal distribution, and the distributions subjected to NFP and FF ground motions are very close.

A multi-objective optimization evaluation model for seismic performance of slopes reinforced by pile-anchor system

The significance means of the seismic reinforcement effect of a pile-anchor system for slope reinforcement has been widely recognized. However, cases of deformation failure and instability sliding of the pile-anchor system itself and the reinforced slope under seismic action continue to be recorded. Therefore, it is crucial to evaluate the seismic performance of slopes reinforced by a pile-anchor system to prevent the system’s failure. Current evaluation models of a slope reinforced by a pile-anchor system mainly focus on slope stability; however, the safety of the pile-anchor system itself is not sufficiently considered in these models. Consequently, in this study, we propose a multi-objective optimization evaluation (MOE) model for evaluating the seismic performance of slopes reinforced by a pile-anchor system that considers slope stability, safety of the pile-anchor system, and dynamic response of the slope. This model considers slope displacement, acceleration amplification factor of a slope, pile displacement, and anchor displacement as negative indexes, and anti-slide pile bending moment, shear force, and anchor axial force as intermediate indexes. The comprehensive weight of relevant indexes is obtained by combining subjective and objective weights, and the seismic reinforcement effect of the pile-anchor system is evaluated subsequently. In conclusion, the MOE model proposed in this study provides a novel solution for the optimization evaluation of a slope reinforced by a pile-anchor system in forthcoming projects.

Dynamic Failure Experimental Study of a Gravity Dam Model on a Shaking Table and Analysis of Its Structural Dynamic Characteristics.

Investigating the dynamic response patterns and failure modes of concrete gravity dams subjected to strong earthquakes is a pivotal area of research for addressing seismic safety concerns associated with gravity dam structures. Dynamic shaking table testing has proven to be a robust methodology for exploring the dynamic characteristics and failure modes of gravity dams. This paper details the dynamic test conducted on a gravity dam model on a shaking table. The emulation concrete material, featuring high density, low dynamic elastic modulus, and appropriate strength, was meticulously designed and fabricated. Integrating the shaking table conditions with the model material, a comprehensive gravity dam shaking table model test was devised to capture the dynamic response of the model under various dynamic loads. Multiple operational conditions were carefully selected for in-depth analysis. Leveraging the dynamic strain responses, the progression of damage in the gravity dam model under these diverse conditions was thoroughly examined. Subsequently, the recorded acceleration responses were utilized for identifying dynamic characteristic parameters, including the acceleration amplification factor in the time domain, acceleration response spectrum characteristics in the frequency domain, and modal parameters reflecting the inherent characteristics of the structure. To gain a comprehensive understanding, a comparative analysis was performed by aligning the observed damage development with the identified dynamic characteristic parameters, and the sensitivity of these identified parameters to different levels of damage was discussed. The findings of this study not only offer valuable insights for conducting and scrutinizing shaking table experiments on gravity dams but also serve as crucial supporting material for identifying structural dynamic characteristic parameters and validating damage diagnosis methods for gravity dam structures.

Full Size Two-Layer Steel Frame–Exterior Wall Panel Shaking-Table Test

A cantilever block wall-panel attachment strip (CBW) flexible connection node was designed to connect precast concrete (PC) exterior wall panels to steel frames. To investigate the performance of the CBW flexible connection node and PC exterior wall panels during earthquakes, a partial two-storey steel frame was extracted from an actual engineering structure, and a full-scale steel frame–exterior wall panel shaking-table model was designed. Two sets of shaking-table tests were conducted under seismic intensity 7, 8, and 9 (Chinese Seismic Intensity Scale) earthquakes. The acceleration and displacement responses of the composite wall panel, open window panel, and integral wall panel along the in-plane and out-of-plane motions were analysed. The acceleration amplification factors of the PC exterior wall panels ranged from 0.753 to 1.400 (in-plane) and from 0.998 to 2.199 (out-of-plane). The CBW flexible connection node had a deformation capacity that could coordinate the deformation of the exterior wall panel and prevent severe damage. The surfaces of the PC exterior wall panels remained intact during a very strong seismic intensity 9 earthquake.

Coupling of horizontal joint and topography effects on seismic response of a single face slope

A concentration of building damage and slope failure near the slope crest has been observed during numerous earthquakes. Documented researches have shown that the combination of topography and geological structure (joint) significantly affects the seismic response of the slope. To investigate this issue, a series of numerical simulation analyses are performed for a slope containing horizontal joints by varying normalized joint stiffness (K), the ratio of normal stiffness to shear stiffness (kn/ks), joint spacing, the slope height, slope angle, and loading frequency. The acceleration amplification factor in the horizontal direction (AAF-X) in the slope distributes fluctuation characteristics when K is less than 1. The AAF-X at the slope crest increases with the increase of kn/ks. Meanwhile, the AAF-X at the slope crest increases first and then decreases with the increasing joint spacing. The AAF-X of jointed slope shows fluctuation change law along the slope surface with the increasing slope height while the AAF-X generally increases for homogeneous slope. The AAF-X at the slope crest of the jointed slope is amplified for different slope heights. A complex interaction exists between the topographic and joint effects on the seismic response of the slope and the two effects cannot be easily decoupled.

Shaking table tests of a switching power cabinet considering physical damage and functionality loss

Switching power cabinets are critical equipment that converts alternating current (AC) to direct current (DC) for electrical power system of telecommunication buildings. Post-earthquake damage to the cabinet may result in entire functionality loss of telecommunication buildings, which will have a significant impact on post-earthquake emergency response. In this study, unidirectional shaking table tests were conducted separately in X-direction and Y-direction to evaluate the seismic responses of a switching power cabinet. The seismic input motion was generated based on required response spectrum of YD 5083 code. The peak table acceleration levels were scaled from 0.3 g to 2.5 g in order to capture progressive damage of the switching power cabinet. Based on the test results, the physical damage and functionality loss of tested cabinet were analyzed first. Then the response characteristics of the cabinet were evaluated and explained in terms of the natural frequency, acceleration, and deformation response. Both outside cabinet and in-cabinet acceleration amplification factors were analyzed. The seismic fragility curves of switching power cabinet were also developed considering four observed seismic damage states.

Investigating the failure mechanism of loess-mudstone landslides with a high water content interface subjected to earthquakes through the shaking table test

Loess mudstone landslides are widespread on the Loess Plateau of China and are primarily triggered by earthquakes or heavy rainfall. Field investigations have revealed the presence of a high-water-content layer at the interface, which often serves as a sliding surface for these landslides. However, the dynamic responses and failure mechanisms of these landslides during earthquakes remain unclear. We conducted a comparative shaking table test on Model 2 (the loess-mudstone slope with a high-water-content interface layer) and Model 1 (the loess-mudstone slope without a high-water-content interface layer) to investigate the failure mechanism of the slope under the influence of earthquakes. The test results revealed that water accumulated at the interface, creating a layer with a high water content that resembled a mudflow after shaking. This layer plays a critical role in the dynamic response and failure mechanisms of landslides. Under seismic loading, the pore water pressure within this layer increases to a positive value, reducing the effective stress of the loess. The acceleration amplification factor in the loess layer was approximately 16 % higher in Model 2 than in Model 1, indicating that Model 2 experienced larger inertial forces. Significant seismic subsidence and X-displacement were recorded in Model 2. Additionally, an increase in the electrical resistivity was observed under 0.8 g, suggesting the development and propagation of cracks within the slope. These findings indicate that the high water-content layer loses its strength and starts to slide initially, which then drags the overlying loess layer, resulting in the generation of penetrated tensile cracks, large X-displacement, and subsidence. The slope experiences slippage and tensile cracking failures. This study provides valuable experimental evidence that enhances our understanding of the failure mechanism of this type of landslide.

Effect of excitation frequency and joint density on the dynamic amplification effect of slope surface on jointed rock slopes

This paper presents the slope dynamic response of jointed rock slopes containing three groups of typical joints and analyzes the effect of input harmonic frequency and joint density on the peak horizontal acceleration (PGA) of the slope surface under vertically impinging SV wave (shear vertical wave) excitation. First, the dynamic response of the slope surface of the bedding slope was investigated with a large-scale shaking table test, and the reliability of the numerical model was verified by the physical modeling. Then, a series of jointed rock slope models with different joint densities were established based on the three-dimensional discrete element software 3DEC. It is found that the natural frequency fn of the jointed slope decreases with the increase of joint density. The effect of excitation frequency f on the slope surface dynamic response of the jointed slope is stronger than that of joint density. The closer the f is to the fn, the stronger the slope surface and slope crest dynamic response is. Notably, taking fn as the critical value of f, the slope surface dynamic amplification mode of jointed slope can be divided into two types: when f ≤ fn, the acceleration amplification factor of X-direction (AAF-X) of the slope surface amplifies monotonically with increasing elevation; when f >fn, the AAF-X of the slope surface shows a fluctuated amplification pattern with the increase of elevation. The results of this paper show that in the seismic design of slope engineering, the influence of site conditions on the frequency spectrum characteristics of ground motion should be considered, and then the optimal design should be carried out.

Combining observed linear basin amplification factors with 1D nonlinear site-response analyses to predict site response for strong ground motions: Application to Wellington, New Zealand

This study develops a method for estimating site amplification that combines instrumentally observed site-specific amplification factors with adjustment factors from nonlinear site-response analyses. This approach provides estimates of site response for large-strain motions based on observations and sophisticated nonlinear modeling. A database of weak-to-moderate intensity ground motions recorded in three basins of Wellington, New Zealand is used to study the observed site amplification. A subset of nine strong-motion stations was selected to perform nonlinear site-response analyses with scaled strong ground motions to assess the influence of nonlinearity on site amplification factors and demonstrate the approach. Different shear-wave velocity ( VS) profiles, constitutive models, and modeling approaches (e.g. one-dimensional (1D) site-response analyses vs empirical [Formula: see text]-based approaches) are used to quantify the sensitivity and modeling uncertainty in the nonlinear site-response analyses. It was found that for soft sites subjected to strong ground motions, there may be a decrease in spectral acceleration amplification factors for periods up to approximately 2 s, relative to the expected linear site response. For longer periods, there is little to no amplification from the effects of soil nonlinearity. However, at stiffer sites, which generally experience less basin amplification in observations, there may be moderate amplification at longer periods when nonlinearity is considered due to softening of the soil profile. Empirical ground-motion models were found to under-represent the observed amplification between basin sites and the nearby reference site, especially at intermediate to long periods, corresponding to resonant frequencies of these basin sites. In addition, the empirical nonlinear site amplification models ([Formula: see text]-based) were found to deviate from nonlinear analyses at large strains, where such models are poorly constrained due to such a limited number of observations.

Shake table test on a five-story residential masonry building strengthened by engineered cementitious composites based on minimum disturbance

Multi-storey masonry structures are popular structural systems for residential buildings in China in the 1970 s, which need strengthening urgently due to poor seismic performance. To save construction time and achieve minimum disturbance, a single-sided engineered cementitious composites (ECC) strengthened method for masonry structures was proposed. To investigate the effectiveness of the strengthening method, two 1/4-scaled 5-storey masonry structures, including a reference unreinforced structure (US) model and a corresponding retrofitted structure (RS) model, were designed and tested by shake table tests. The comparisons between the US model and the RS model were analyzed in terms of the natural frequency, acceleration amplification factor, acceleration response, and storey drift response. The results show that the strengthening method can improve the seismic performance of the masonry structure. The connection method can ensure that the existing masonry walls and ECC layers work together. The initial natural frequency of the RS model is 1.3 times that of the US model. The maximum storey drift of the US model is 3.0 times that of the RS model at PGA = 0.550 g. To ensure the strengthening efficiency, the acceptable structural aspect ratio range for the strengthening method was suggested, and an improved strengthening method was proposed.

Comparative experimental study on shaking table test of small radius curved bridge considering different connection types between pier and beam

During the Great Wenchuan Ms 8.0 earthquake, many small-radius curved bridges suffered varying degrees of damage, including Baihua Bridge, Huilan Overpass, and Xiaohuangou Bridge. To understand the damage mechanism, shaking table tests were conducted on two scaled bridge models with different middle pier connection types. In one model, the middle pier and beam were cast monolithically together (CM bridge), while the other had a fixed support installed at the pier-beam connection (FS bridge). Both bridges were subjected to two earthquake ground motions. Visually, damage differed considerably between the bridges. The CM bridge exhibited many horizontal and circumferential cracks at the top and bottom. Meanwhile, the FS bridge concrete was crushed at the top of the middle pier, which must be paid attention to. Amplification factors, maximum drift ratios, residual drift, planar rotation angles, and bearing slip were analyzed for both bridges. For both structures, amplification factors in the X and Y directions decreased with stronger ground motions, while those in the Z direction showed an opposite trend; meanwhile, maximum drift ratios, residual drift, rotation angles, and bearing slip all increased with stronger motions. The acceleration amplification factors of the CM bridge increased with greater ground motion, rising rapidly. The CM bridge saw a maximum drift ratio of 7.07 versus 3.16 for the FS bridge. The trend for the CM bridge was a gradual increase, while the FS bridge had a sudden increase after the maximum drift ratio reached 1.61%. The CM bridge planar rotation angle rose gradually to 0.23°, while the FS bridge angle increased much faster, reaching 0.54° or 2.35 times that of the CM bridge. The FS bridge concrete splitting failure demonstrated vulnerability to seismic events exceeding the design level and the structural measures in this region should be enhanced in the design.

Shaking table tests on the influence of geosynthetic encasement stiffness on the shear reinforcement effect of GESC composite foundation

This paper presents an experimental study of shaking table tests on two geosynthetic encased stone columns (GESC) composite foundation models with different geosynthetic encasement stiffness to investigate the influence of geosynthetic encasement stiffness on the shear reinforcement effect. The reduced-scale GESC composite foundation models were designed according to the similitude relationships by scaling the model geometry, geosynthetic encasement stiffness, and input motions for shaking table tests in a 1 g gravitational field. The GESC composite foundation models were constructed using poorly graded sand, gravel, and geotextile encasement, and then were excited using a series of sinusoidal input motions with increasing peak acceleration. The acceleration amplification factors for the GESC composite foundation model with higher geosynthetic encasement stiffness are larger than those of the lower geosynthetic encasement stiffness model due to the increased stiffness of the composite foundation. The higher geosynthetic encasement stiffness composite foundation has smaller settlements and lateral displacements under the same input motions compared to the lower geosynthetic encasement stiffness composite foundation. The incremental geosynthetic encasement tensile strains increase with increasing input acceleration for both models. The longitudinal tensile effect of geosynthetic encasement plays an important role on the shear reinforcement mechanism of GESC.

Shaking Table Testing of a Scaled Nuclear Power Plant Structure with Base Isolation

To investigate the seismic performance and isolation effect of a high-temperature gas-cooled reactor, a 1/20 scale model including a reactor, a spent-fuel plant, and a nuclear auxiliary plant was fabricated. In addition, 220 mm lead-rubber bearings were designed and produced for use in the shaking table test, which included both isolated and nonisolated conditions. Two historical earthquake records and three artificial earthquake motions were used to input the ground motion in the tests. The results demonstrated that the seismic performance of the plant was better and that the structure was in an elastic state, under a safe shutdown earthquake event. Isolation bearings were found to effectively reduce the dominate frequency of the structure. The acceleration amplification factor of the superstructure was found to be less than 1. The isolation test results showed that the peak of the floor response spectrum at the pressure vessel support was less than 0.1 g. In the nonisolation test, the peak of the floor response spectrum was greater than 1 g. In the isolation test, the relative displacement of the structure was less than 1.1 mm, which was relatively small. The structure maintained a good isolation performance and exhibited improved safety under extreme ground motion.

Dynamic response characteristics of shaking table model tests on the gabion reinforced retaining wall slope under seismic action

In the present study, a series of shaking table model tests were performed on a slope with a gabion reinforced retaining wall. Transfer functions were employed to compute the inherent frequencies of the slope. Furthermore, the investigation examined various aspects of the slope, including the peak acceleration amplification factor, incremental dynamic stresses, displacements, and tensile forces. Additionally, the study employed the Hilbert Huang transform (HHT) to analyze the slope's time-frequency characteristics and energy distribution. The findings of the study revealed that there is an inverse relationship between the amplitude of the input seismic wave and the natural frequency of the top of the gabion reinforced retaining wall slope. As the amplitude of the seismic wave increases, the natural frequency of the slope decreases. The amplification factors for peak acceleration were all found to be less than 1.9, suggesting a notable dissipation of seismic energy in comparison to typical slopes. The response of incremental dynamic stress was most pronounced in the middle section of the slope, followed by the top of the slope. The magnitude of the incremental displacement was found to be highest at layer 4, whereas the incremental tensile force exhibited its maximum value at layer 5. The dynamic response exhibited the least pronounced characteristics at the lower portion of the slope, demonstrating the most stable behavior. The peak frequencies observed in the Hilbert marginal spectrum displayed comparable characteristics to the natural frequencies.

Numerical comparative study on seismic response of half-span and full-span scaled models of a floating type cable-stayed bridge

This study compares the results of numerical simulations of half-span and full-span cable-stayed bridge models based on the seismic response of the pylons and main girders subjected to earthquake loads. The half-span model represents the most critical condition of the bridge during the construction phase, while the full-span model represents the bridge in operational phase. The three-dimensional finite-element modeling of the two bridge models uses data from the longest existing cable-stayed bridge in Indonesia which was scaled down geometrically to 1/160, using Midas CIVIL software. The Kobe earthquake record from the PEER Strong Motion Database was used in this study by applying the spectral matching method to modify its acceleration according to the location of the existing bridge being analyzed. This study also examines the influence of the directional effects of earthquake load relative to the longitudinal axis of the bridge, namely 0, 45, and 90 degrees. The results of the analysis show that for the half-span bridge model, the maximum acceleration occurs at the top of the pylon due to earthquake excitation at 90 degrees direction, with an amplification factor of 4.658, while the amplification factor in full-span bridge conditions is only 2.44. In addition, in both the half-span and full-span bridge models, the largest acceleration amplification factor occurs in the main girder that is caused by earthquake excitation at 90 degrees direction. The largest transverse displacement occurs at the free ends of the main girder, but not in the full-span model. The results of the study indicate that during the detailed design process the designer has to consider the effect of earthquake on the strength and stability of the bridge during construction especially if the balanced cantilever method applies.

Shaking Table Test of a Split-Foundation RC Frame Structure with One Lower Story Compared with a Conventional RC Frame Structure

Split-foundation (SF) building structures, as a kind of hill-side buildings, are widely used in mountainous regions due to the scarcity of plain areas. In order to experimentally investigate the seismic responses of the SF structure, shaking table test was carried out on two 1/8-scale models: a split-foundation RC frame structure supported by foundations at two different levels and a conventional RC frame structure supported by foundations at one single level. The failure patterns, dynamic characteristics, acceleration responses, displacement responses, and torsion responses of the two models were assessed and compared under seismic ground motions. The test results indicate that the two models were severely damaged after the last intensity level excitation and showed an intermediate failure mechanism. The damage to the SF model was uneven and special with relatively severe damage of the upper grounded columns. The difference in natural frequencies between the two models resulted from the effect of the lower story on lateral stiffness, and the effect was relatively dramatic in the transverse direction. The difference in structural stiffness led to larger acceleration amplification factors of the SF model and smaller acceleration amplification factors in the longitudinal direction. Although the restriction at upper ground level created a certain effect on displacement responses of the SF model especially in the first story, the curve shapes of displacement responses of the two models were similar from the first floor to fourth floor. In addition, the torsion responses of the SF model, especially in the first story (upper ground story), were obviously much larger than those of the conventional model. The torsional effect cannot be ignored in the SF structure which is a torsionally sensitive structure.

Influence of seabed profile on the seismic response of monopile-supported offshore wind turbines including dynamic soil-structure interaction

In this article, the seismic response of four different Offshore Wind Turbines (OWTs) from 5 to 15 MW, founded on monopiles embedded in homogeneous and non-homogeneous soil profiles with equivalent shear-wave velocities from 100 to 300 m/s is analysed. Two types of variable soil profiles with a semi-parabolic variation of the shear-wave velocity as depth increases are considered. The system seismic response under ten different accelerograms is computed through a finite element substructuring model in frequency domain. The foundation behaviour is obtained by a continuum model including kinematic and inertial interaction. Several models, in addition to that of rigid base condition, are considered to determine the influence of soil-structure interaction (SSI), as well as the contribution of each kinematic interaction (KI) factor. The seismic response of the OWTs is obtained in terms of maximum shear forces and bending moments at mudline level, as well as the acceleration amplification factor at hub level. It is found that the maximum response is produced when SSI is considered, including both the inertial and kinematic interaction. The differences arising due to the soil profile definition are shown to be mainly related to the rotational KI factor, which significantly affects the second vibration mode of the system. The largest responses are obtained for the homogeneous equivalent profile.

Seismic Behavior of Arch Bridge Abutments under Sandy-Gravel Foundations with Different Grouting Depths: Insights from Shaking Table Tests

For arch bridges built on deep soil sites, significant seismic amplification effects were observed in the overlying soil layer from past earthquake events, and these effects can lead to more serious structural damage. Grouting-strengthening technology has recently been recommended as an innovative geotechnical method for strengthening soils to retain the seismic amplification phenomenon under strong ground motions, and it has exhibited advantages in improving the lateral resistance of soils. However, grouting reliability depends on the soil type, jet pressure, and engineering costs, and there has been little research on the differences in the natural period and seismic capacity caused by grouting behavior. To fill this research gap, based on a practical engineering prototype, shaking table tests were performed for semigrouting and all-grouting cases in sandy-gravel soil with a simple bridge abutment to investigate the difference in the seismic capacity of the two soil–foundation–abutment systems. The acceleration response difference between the grouting zone and the surrounding soil, characteristic periodic variation of the response spectrum of the soil and abutment, grouting depths, and seismic energy dissipation mechanism of the soil were analyzed. The results show that the acceleration amplification factor of the all-grouting foundation was smaller than that of the semigrouting foundation. However, the acceleration amplitude of the all-grouting foundation was larger owing to the higher seismic input energy. Significant differences in the lateral resistance mechanism between semigrouting and all-grouting foundations were observed. The grouting foundation realizes consistent acceleration and displacement through load transmission and soil–structure interaction mechanisms. The results demonstrate the suitability of soil thicknesses for significantly reducing the seismic demands of abutments and provide guidance for foundation treatment methods in relevant engineering projects.

Shaking table test of fully assembled precast concrete shear wall substructure with tooth groove connection and vertical reinforcement lapping in reserved hole

In this paper, an innovative fully assembled precast concrete shear wall structural system with tooth groove connection and vertical reinforcement lapping in reserved hole was proposed, and the constructional requirements and joint assembly process were elaborated in detail. Based on the similarity theory, a 1/2 scaled fully assembled precast shear wall substructure was designed and manufactured. The damage mode, dynamic characteristics, acceleration response, displacement response, seismic action response, inter-storey shear response and strain response of the fully assembled precast concrete shear wall substructure with tooth groove connection and vertical reinforcement lapping in reserved hole under the different earthquake excitations were comprehensively analyzed by shaking table test, and the connection performance and seismic performance of the substructure in high intensity areas were investigated. The research results showed that the cracks at the horizontal joint of the 1st floor were completely penetrated, accompanied by slight concrete spalling, the 1st floor shear wall perpendicular to the input direction of seismic excitation was slightly uplifted, and there was no obvious damage in other parts. Overall, the tooth groove connection and vertical reinforcement lapping in reserved hole was reliable. Besides, the dynamic characteristics and seismic response of the substructure were consistent with the three-stage test phenomena. The acceleration amplification factor, storey displacement, seismic action increased with the increase of the height of the substructure and the excitation of PGA. When the excitation of PGA = 0.638 g, the maximum inter-storey drift was 1/213, which was in line with the plastic limit of 1/120. On the whole, the integrity of the substructure remained good and there was no danger of collapse. Finally, a comprehensive seismic performance evaluation method suitable for fully assembled precast concrete shear wall substructure with tooth groove connection and vertical reinforcement lapping in reserved hole was proposed with inter-storey drift and damage index as quantitative indicators.

Shaking table tests on 0.5-scale multistory models of plate-type modular steel and composite buildings with semi-rigid corner connections

To study the dynamic properties and seismic response of global plate-type modular steel and composite structures with semi-rigid corner connections, shaking table tests were conducted on three 0.5-scale multistory plate-type modular models. This paper presents the testing program and results, including the dynamic characteristics and earthquake performance. Under the excitation of seismic loads, the bolts connected to the corners were easily loosened, the gaps between the composite wall plates increased, and the concrete surface layer of doorways and windows was damaged and fell off. The test results showed that as the peak ground acceleration increased, the fundamental frequency decreased, the damping ratio increased, and the acceleration amplification factor decreased. The initial lateral stiffness of plate-type modular composite structures with wall panels was eight to nine times that of plate-type steel frame structures owing to the strong skin effect of the wall panels. The stiffness of complete composite structures decreased by approximately 50% under a nine-degree rare seismic intensity owing to the deterioration of the bolt rotation stiffness and damage to the wall panel. The maximum interstory drifts of the complete plate-type modular building under rare earthquakes were small, which meets the requirements of the seismic design code.