Shaking Table Tests Research Articles

Shaking table test and simulation on seismic performance of aluminum alloy reticulated shell structures under elastic and elastic-plastic stage

This study aims to analysis the dynamic characteristics and seismic response behavior of aluminum alloy reticulated shell structures especially pay attention to the internal force changes in the elastic and elastic-plastic stages. A scaled test model of aluminum alloy single-layer spherical reticulated shell was designed and manufactured, and a shaking table test was carried out to obtain its dynamic characteristics and seismic response. The modal parameters of the reticulated shell structure, including frequency, modal shape and damping ratio, are obtained by white noise scanning frequency and frequency domain decomposition (FDD) technology. The response of the reticulated shell structure in the elastic stage and the elastic-plastic stage is discussed, including the node acceleration, displacement and strain response under different peak ground acceleration (PGA). The finite element method (FEM) is used for numerical simulation analysis. An effective numerical simulation method for analyzing the seismic performance of aluminum alloy single-layer reticulated shells is proposed. The internal force development and structural displacement of structures under strong earthquakes are studied. The test results show that under the action of horizontal ground motion, the vertical stiffness of the small rise-span ratio aluminum alloy reticulated shell is small, and the radial and ring members mainly bear the out-of-plane bending moment and axial force. In addition, the horizontal deformation of the reticulated shell structure and the in-plane rotation of the joints are the main reasons for the members to enter the plasticity, resulting in bending and torsional deformation of the members in the weak area. Axial pressure and bending moment control the force mechanism of the members, which is the cause of bending and torsional instability of the members.

Optimization design and shaking table test of tuned mass damper for enhancing seismic performance in thermal power plants

Optimization design and shaking table test of tuned mass damper for enhancing seismic performance in thermal power plants

Sub‐assemblage testing and fragility analysis of connections of continuous‐plasterboard suspended ceiling systems

AbstractPast earthquake reconnaissance reports highlighted extensive seismic damages to suspended ceiling components and connections, including instances of complete ceiling failures. The seismic qualification of these nonstructural elements typically requires comprehensive evaluation through full‐scale shake table testing. However, such experimental evaluation is ordinarily not possible for every change made in various components and connections of ceiling systems due to the cost and effort involved. A feasible alternative is to obtain the behavior of components and connections from sub‐assemblage testing and incorporate them in appropriate numerical ceiling models to derive mechanical responses for developing alternative or new installation schemes. This paper considers critical connections of three continuous‐plasterboard suspended ceiling systems that were evaluated using shake table‐generated motions. The connections were classified according to their attachment to typical floors and walls of building structures, and sub‐assemblage testing was conducted using both monotonic and cyclic displacement loading. The observed failure modes in each connection were detailed, and appropriate damage states were assigned as the basis for constructing connection fragility curves. The results of the sub‐assemblage testing were presented in terms of the hysteresis responses, envelope curves, nonlinear backbone curves, and cumulative energy dissipation curves. Additionally, multilinear models of the connections were derived by approximating nonlinear backbone curves’ initial‐ and post‐yield behaviors. These multilinear models were further idealized to derive three equivalent linearized models for simplified yet reasonably accurate results for linear structural analyses. Finally, fragility curves were derived for all connections, considering their cyclic displacement failure capacities.

Shaking table test study of anti-dip rock slope with complex structural plane under earthquake

Shaking table test study of anti-dip rock slope with complex structural plane under earthquake

Shake-Table Testing of a Brick Masonry Groin Vault: Overview of Blind Predictions and Postdictions and Comparison with Experimental Results

Shake-Table Testing of a Brick Masonry Groin Vault: Overview of Blind Predictions and Postdictions and Comparison with Experimental Results

Shaking Table Test and Numerical Modeling of Seismic Behavior of Rectangular Tunnel Structures Embedded in Soft Clay

In this paper, a series of 1-g shaking table model tests were carried out to investigate the seismic behavior of a relatively stiff rectangular tunnel structure installed in soft clay bed, accounting for different ground motions with varying peak accelerations. Using a validated numerical analysis procedure, a suite of three-dimensional (3D) finite element (FE) analyses was performed to systematically study the factors of tunnel burial depth, seismic intensity, flexural rigidity of the middle column and tunnel wall thickness on the seismic response of rectangular tunnel structures installed in clayey ground. It was found that, with the increasing burial depth, the seismic response of rectangular tunnel structure became more intense due to the increased inertial force arising from the overlying clay; in terms of improving the seismic performance of tunnel structure, increasing tunnel wall thickness seemed more effective than increasing flexural rigidity of the middle column. Furthermore, it was found that the existing simplified approaches generally tended to overestimate the earthquake-induced racking distortions of rectangular tunnels installed in clayey ground. A new semi-empirical relationship was derived for better correlating the racking ratio with flexibility ratio for rectangular tunnels embedded in soft clays, which could provide a useful reference for the seismic design and risk assessment of similar clay-tunnel systems.

Relationship between shaking table tests and simultaneous in-plane and out-of-plane cyclic tests in masonry walls strengthened with bed joint reinforcement

Relationship between shaking table tests and simultaneous in-plane and out-of-plane cyclic tests in masonry walls strengthened with bed joint reinforcement

Dynamic performance investigations of a full-scale unanchored thin-walled steel fluid storage tank via shake table tests

Theoretical models proposed in the literature and seismic design codes make the basis of analysis and the design procedures of fluid storage tanks. These models are derived based on many simplified and approximate assumptions. Under realistic conditions, however, different factors cause violation of these assumptions, causing the fluid flow and fluid–structure interaction (FSI) to diverge from theories. In this research work, 38 swept-sine tests and 63 seismic ground motions were applied to a full-scale highly flexible unanchored thin-walled stainless steel fluid tank. The experimental natural frequencies of the system for three different aspect ratios of 2.1, 2.8, and 3.5 were calculated and compared with the theoretical ones. Damping ratios for different modes were calculated using the half-power bandwidth analysis. Experimental results revealed discrepancies between the theoretical and experimentally detected natural frequencies, especially for the convective mode. Closer matches were found for the aspect ratios of 2.8 and 3.5, for the impulsive mode. Acceleration amplification factors at different heights of the shell were calculated which showed a nonlinear behaviour with a descending trend from the base to the mid-height and then an ascending one towards the fluid surface. Maximum acceleration amplification factor occurred at the surface of the fluid. The axial strains around the base are maximum and decrease bi-linearly towards the upper heights of the shell. Effects of the input excitation frequency content over the structural responses of the system were examined. Frequency characteristics of the input excitation considerably affected the maximum acceleration amplification factors and axial strains in the shell.

Shaking table test and numerical simulation of rocking wall frame structure considering dynamic soil-structure interaction

This study investigates the seismic response of a rocking wall frame structure considering dynamic soil-structure interaction (DSSI) through shaking table tests. A comparison with conventional frame structures and structures with fixed-base foundations is made to examine the influence of DSSI effects on various aspects including structural damage distribution, dynamic characteristics, and floor responses. Test results indicate that the presence of a rocking wall reduces structural responses across different site conditions, although the reduction is less significant under soft soil conditions compared to fixed-base foundation conditions. Overall, DSSI diminishes the mitigating effect of the rocking wall on the maximum structural response. Furthermore, a three-dimensional finite element model of the shaking table test is established. The numerical model employs the equivalent linear method to simulate the soil's nonlinear behavior and incorporates the concept of the rocking wall. Comparative analysis between experimental and simulated results demonstrates that the model effectively predicts the dynamic response of the rocking wall frame structure in DSSI systems.

Life Prediction and Reliability Evaluation of Reinforced Concrete Frame Structures Considering the Collision Response Under Earthquake Conditions

Firstly, in this study, we utilize the high-order element model (truss link model) simulation method in OpenSees (3.7.0) software and verify the feasibility of this method by comparing it with the shaking table test. Secondly, the structural dynamic response of adjacent structures with different performance levels, spacing, and layout forms under large earthquakes is analyzed, and the corresponding structural failure probability is studied. Furthermore, the life distribution within the design service life of the structure is predicted according to the nonparametric Kaplan–Meier estimation model. Finally, the reliability of adjacent structures is evaluated by using the joint engineering demand parameters. The analysis method of replacing the theoretical analysis based on engineering experience and certainty in the current specification with probability analysis is proposed, which provides a more reliable theoretical basis for decision-making regarding the reinforcement, maintenance, or demolition of structures in the later stage.

Design Method of a Novel Interface Connection Device for Multiscale Test Model Considering Multiparametric Similarity of Internal Forces

ABSTRACTThe multiscale model of building structures, as a balanced solution between accuracy and cost, has been widely used in the analysis of structural seismic performance. A reasonable interface connection method can accurately ensure load transfer and motion coordination between models of different scales. In this paper, a novel interface connection device and the corresponding design method for a multiscale test model of building structures were proposed, in which the upper structure with smaller sized components was replaced by a simplified story‐scale model, and the lower structure was adopted as a component‐scale model. The overall and local equations of motion for this multiscale model were established. For the interface connection between different scale models, a design method considering multiparametric similarity of shear force, axial force, and bending moment was proposed. In this method, the internal nodes at the interface of the component scale model were decomposed, and the coupling relationship of internal force between two adjacent nodes was established. The axial force of each node was decoupled into the interstory shear force and bending moment provided together. Additionally, the overturning moment is provided by adding the overlapping domain. According to the equilibrium relationships of the nodes at the interface, the corresponding transfer matrix was provided, and the design method of the interface connection device was proposed. The accuracy and feasibility of the method were validated by static and shaking table tests on a frame structure.

Dynamic performance of ground supported circular water tank using shaking table

One of the most important lifelines for the human population is the water tank, which needs to be able to continue operating as usual both during and after earthquakes. Due to inadequate design techniques, structures are mainly intended to support static loads. The impact of dynamic loading is not taken into account. When resonance occurs, the effect is even more severe. The main objective of this work is to perform shaking table tests and study the dynamic performance of circular water tanks resting on the ground during shaking. For this investigation, three tanks with different height-to-diameter ratios have been taken into consideration. For various combinations of frequency, amplitude and water height in the tank, the hydrodynamic pressure at various places and the height of the sloshing wave during shaking have been measured experimentally. In comparison to the static water pressure on the container, it is discovered that dynamic pressure increases by 20%–50% during shaking. Resonant frequency drops with increasing tank diameter for a given water head at constant amplitudes.

Investigation of Seismic Behavior of Slope Supported by Pile-Anchor Structure with Dampers

ABSTRACT The pile-anchor structure has been widely studied by global researchers. However, there is still little research on seismic optimization measures considering energy dissipation. In this research, the seismic performance of the pile-anchor structure is optimized by setting viscous dampers on the anchor cables. Shaking table tests are conducted to compare the seismic response of this new structure with that of the ordinary structure. Meanwhile, an analysis of the seismic energy dissipation law under the support of both structures was conducted. Those results show that the seismic performance of the pile-anchor structure can be greatly improved by setting dampers.

Performance-based seismic design of controlled rocking reinforced concrete frame with beam-end hinge

This study investigates the seismic performance of the Controlled Rocking Reinforced Concrete Frame with Beam-end Hinge (CR-RCFB) system. The novelty of our research lies in the development and validation of a finite element model that accurately predicts the dynamic response of CR-RCFB structures under various seismic conditions, specifically focusing on the innovative use of joint stiffness ratios and the integration of dampers. A finite element model was developed and validated through shaking table tests. The research examined the dynamic responses of the CR-RCFB under ten ground motion records, varying the node relative stiffness ratios. The interstory displacement amplification coefficient (α) was found to range between 1.08 and 1.20, while the earthquake-reduction coefficient (β) varied from 0.8 to 0.3 depending on the stiffness ratio. Results indicate that node stiffness ratios between 0.01 and 0.25 optimize performance, minimizing peak interstory displacement and base shear response. Additionally, integrating dampers increased the damping ratio from 14.48% to 30.51%, enhancing energy dissipation by shifting absorption from plastic deformation to damper yield. Pushover analysis was used to recalculate and validate the parameters α and β, demonstrating that the integration of dampers effectively controls displacement response. These findings suggest that the CR-RCFB system with integrated dampers offers enhanced seismic resilience by reducing displacement and base shear forces compared to traditional reinforced concrete frames.

Shake table tests on story-to-story pounding between adjacent RC buildings

Pounding between adjacent buildings and their devastating effects have been frequently reported during numerous major earthquakes. Although poundings exhibit more destructive effects on RC buildings compared to steel buildings, the majority of previous experimental studies have mainly concentrated on steel specimens. Furthermore, there has been a notable scarcity of extensive large-scale experimental studies on this subject. Therefore, the primary objective of this study is to experimentally determine the effects of different types of pounding on the seismic responses of RC buildings. To this aim, three half-scaled two-story RC specimens were constructed and were tested. In the tests, three cases were considered: (i) without pounding, (ii) pounding between taller and shorter buildings (slab-to-slab interaction at one floor), and (iii) pounding between buildings with equal heights (slab-to-slab interaction at the two floors). The experimental results showed that pounding and its types played a critical role in structural responses such as floor accelerations, displacements, hysteretic responses, and dynamic characteristics. Additionally, each pounding type led to different damage mechanisms in the specimens.

Bridge Monitoring Using Smartphones Installed on Driving Vehicles: Oriented to Crowdsourcing Model

The acquisition of bridge frequency by using the ubiquitous ordinary passenger vehicles and smartphones in cities has attracted an increasing amount of attention. This study proposes a bridge monitoring method and develops a vehicle–bridge crowdsourcing monitoring (VBCM) platform for public participation. It takes smartphones carried by vehicles as monitoring terminals for a long-term bridge monitoring task. To validate the feasibility of available smartphone brands as a signal collector, a small shake table test is carried out and the processing scheme for the smartphone sampling data is investigated. A smartphone sensor frequency gain technique is proposed to satisfy the fusion of multisensor data in different smartphones. Furthermore, a magnetic target identification technique is proposed to pick up and extract the bridge response signal segment corresponding to the vehicle’s entering and leaving, as well as to eliminate redundant data. To this end, the network of multiple smartphones is synchronized. For the sake of applicability and feasibility, a series of scaled experiments are conducted in the laboratory considering an adapted toy car driving over a simply supported steel bridge. The results demonstrated the practicality of the proposed methodology. The combination of easily accessible smartphones oriented to a crowdsourcing model and a driving vehicle lowers the threshold for the bridge monitoring process, which also pinpoints a potential for future structural health monitoring development.

Investigation on internal evolution process of slope under seismic loading: insights from a transparent soil test and shaking table test

Earthquakes are a primary factor in triggering slope instability and pose a serious threat to transportation. However, current research on the internal deformation of slopes under seismic loading remains limited. To investigate the effects of different seismic loadings on the evolution process and failure mode of slopes, a novel experiment combining transparent soil materials and shaking table tests was proposed in this study. Using a self-designed shaking table system, sine waves with amplitudes of 0.10 g, 0.15 g, and 0.20 g and frequencies of 3 Hz, 5 Hz, and 8 Hz were applied. Based on Particle Image Velocimetry (PIV) technology and non-intrusive monitoring techniques, displacement and velocity contour maps, whole-field average displacement and failure mechanism of the slope were analyzed. The results show that, as the vibration persists, the slope transitions from initial shallow linear sliding to overall circular arc sliding, exhibiting an obvious progressive traction failure mode. The evolution process of the slope could be divided into three phases: shallow low-speed sliding phase, overall rapid sliding phase, and overall low-speed sliding phase. Furthermore, the amplitude of seismic loading has a greater influence on slope deformation compared to its frequency. This novel experiment offers important insights into the internal evolution process of slopes under seismic loading.

Investigation on the Seismic Damage and Identification of Lateral Stiffness for Ancient Timber Structures

ABSTRACTThis paper investigates the seismic damage and identification of lateral stiffness for ancient timber structures. Based on the shaking table test of a palace‐style timber structure, the lateral displacement responses, interstory equivalent lateral stiffness (IELS), and sensitivity of lateral displacement to degradation of IELS were analyzed to investigate the degradation and identification of IELS. The state and observation equations of a simplified mechanical model of the timber frame considering the friction slipping of the column base were predicted. Considering the noise disturbance in the test, the IELS of the model was identified by the partial least squares–singular value decomposition (PLS‐SVD) and extended Kalman filter (EKF) method. Results shown that the ratio of the IELS of the column frame layer to Ru‐Fu layer decreased as the seismic damage increased, and the peak lateral displacement was more sensitive to the damage of the column frame layer than the Ru‐Fu layer. Under nondamage conditions, the identification error of the IELS was about 10%, while the error ranged from 15% to 20% under damage conditions. Through the identification of the equivalent lateral stiffness of the Xi'an bell tower, it was validated that the hybrid method is effective in monitoring the IELS of ancient timber structures.

Theoretical and experimental investigation of flexible air spring stiffness in a tuned liquid column gas damper for vertical vibration control

This study investigates the effectiveness of equivalent linear air spring stiffness in a Vertical Tuned Liquid Column Gas Damper (VTLCGD) for reducing vertical structural vibrations, particularly considering different sealing conditions. The VTLCGD system, designed with a single sealed vertical air column, allows flexible frequency tuning by adjusting the air spring stiffness. It aims to be used in low-frequency structures where conventional VTLCGD designs with two sealed ends are less efficient. The geometric configuration and working principle of the VTLCGD are first described. The equation of motion is derived using liquid dynamic equilibrium and the pressure-volume relationship, with expressions for natural frequency and control force validated through shaking table tests conducted with varying VTLCGD lengths. Experimental investigations are conducted to examine the parameters affecting damper performance using pressure data. The system's vibration reduction performance is then numerically evaluated on a cantilevered floor subjected to human walking. The numerical results, based on the equation of motion for liquid displacement and natural frequency, show good agreement with experimental data, which confirms the effectiveness of using linearized air spring stiffness for frequency tuning. The effects of total liquid length and height difference on control force are further investigated, and a polytropic index of 1.2 is determined for the VTLCGD frequency formula. The VTLCGD system achieves a maximum vibration reduction of 52.63 % in acceleration response on the cantilevered floor compared to the uncontrolled case. Moreover, the variation in stiffness due to changes in the sealing condition is presented to validate the damper's adaptability over a wide frequency range.

Study on seismic response characteristics of living stumps slope based on large-scale shaking table test

A large-scale shaking table test of a living stump slope with a geometric similarity ratio of 1:7 was designed and completed. The peak acceleration, acceleration amplification factor, and displacement response patterns of living stumps slopes under different types of seismic waves and excitation intensities were obtained. The time-frequency and energy variation characteristics were analyzed using the Hilbert-Huang Transform (HHT). The results showed that: (1) Regardless of the type of seismic wave, the peak acceleration and acceleration amplification factor of the living stumps slope surface are positively correlated with relative height and seismic excitation intensity. When the excitation intensity is ≤ 0.4 g, the acceleration amplification effect is more pronounced; when the excitation intensity is > 0.4 g, the acceleration amplification effect weakens. (2) Under the action of different seismic waves, the peak displacement of slope surface shows amplification effect along the elevation, and increases with the increase of excitation intensity. In addition, the incremental displacement gradually decreases from the toe to the top of the slope, which is expressed as D2 > D3 > D1 > D4 > D5. The peak displacement at the top of the slope is the greatest, but the incremental displacement is the smallest; the peak displacement at the toe of the slope is the smallest, but the incremental displacement is relatively large. (3) Regardless of the type of seismic wave, living stumps slope shows the characteristics of filtering the low-frequency components of the seismic waves and amplifying their high-frequency components. At the same time, the seismic Hilbert energy gradually accumulates along the elevation. PSHEA and PMSA significantly increase with elevation and excitation intensity, and they reach the maximum at the top of the slope. (4) The seismic Hilbert energy is positively correlated with the relative height and excitation intensity, and reaches the maximum at the top of the slope. With the accumulation of seismic Hilbert energy increases, the dynamic response parameters such as peak acceleration, acceleration amplification coefficient and displacement also increase synchronously, reaching the maximum at the top of the slope. The research conclusions can provide an experimental basis for the seismic design of living stumps slopes.