scholarly journals Seismic Performance of Deposit Slopes with Underlying Bedrock before and after Reinforcement by Stabilizing Piles

2021 ◽  
Vol 11 (12) ◽  
pp. 5664
Author(s):  
Zhiliang Sun ◽  
Lingwei Kong ◽  
Wei Bai ◽  
Yong Wang
Keyword(s):  
Seismic Performance ◽  
Seismic Waves ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Ground Acceleration ◽  
Stabilizing Piles ◽  
Multi Stage ◽  
Before And After ◽  
Table Model ◽  
Input Motion

The seismic performance of stabilizing piles used to reinforce underlying bedrock in a deposit slope is a complex soil–structure interaction problem. Two centrifuge shaking table model testswere conducted to ascertain the dynamic responses of the underlying bedrock deposit slopes without and with the use of stabilizing piles during an earthquake. Multi-stage seismic waves with various peak accelerations were applied from the bottom of each model. The differencesin the response accelerations between the deposit and bedrock increase significantly with the increase in amplitude of the input seismic waves. The presence of the rock-socketed stabilizing piles can bridge the uncoordinated movement of the bedrock and the overlying deposit to some extent. The resultant force arising from a distributed load increment on the piles caused by an earthquake is mainly concentrated in the upper part. With increases in the peak ground acceleration of the input motion, the resistance of the bedrock in front of the stabilizing piles increases and the peak resistance under the bedrock surface of the stabilizing piles gradually moves downwards.This finding indicates that the strong seismic motion significantly changes the embedded working state of the stabilizing pile.

scholarly journals Seismic Performance of Deposit Slopes With Underlying Bedrock Before and After Reinforcement by Stabilising Piles

2021 ◽  
Author(s):  
Zhiliang Sun ◽  
Kong Lingwei ◽  
Bai Wei ◽  
Wang Yong
Keyword(s):  
Seismic Performance ◽  
Seismic Waves ◽  
Bending Moment ◽  
Resultant Force ◽  
Shaking Table ◽  
Slope Instability ◽  
Dynamic Responses ◽  
Seismic Excitation ◽  
Ground Acceleration ◽  
Response Characteristics

Abstract The seismic performance of stabilising piles used to reinforce underlying bedrock in a deposit slope is a complex soil-structure interaction problem, on which there is limited design guidance on the optimum use of a single row of rock-socketed piles to reinforce such slopes. Two centrifuge shaking-table model tests at a geometric scale of 1:50 were conducted to ascertain the dynamic responses of the underlying bedrock deposit slopes without and with the use of stabilising piles during an earthquake. Multi-stage seismic waves with various peak accelerations were applied from the bottom of each model. Under seismic excitation, the differences in the response accelerations between the deposit and bedrock increase significantly with the increase in amplitude of the input seismic waves. The two are prone to uncoordinated movement, which leads to slope instability. Setting stabilising piles reduces the crest settlement and angular deformation and changes the natural frequency of the slope crest. The presence of the rock-socketed stabilising piles can bridge the uncoordinated movement of the bedrock and the overlying deposit to some extent. According to the mobilised pile bending moment, shear force, lateral pile-soil load distribution, and pile displacement, the dynamic response characteristics of stabilising piles under continuous multi-level seismic excitation were analysed. The resultant force arising from a distributed load increment on the piles caused by an earthquake is mainly concentrated in the upper part (the point of action of the resultant force is 1.54m below the slope surface). With increases in the peak ground acceleration (PGA) of the input motion, the resistance of the bedrock in front of the stabilising piles increases; moreover, with the increase of PGA, the peak resistance under the bedrock surface of the stabilising piles gradually moves downwards. This finding indicates that the strong seismic motion significantly changes the embedded working state of the stabilising pile.

scholarly journals Shaking Table Model Test and Seismic Performance Analysis of a High-Rise RC Shear Wall Structure

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Shujin Li ◽  
Cai Wu ◽  
Fan Kong
Keyword(s):  
Seismic Performance ◽  
Model Test ◽  
Shaking Table Test ◽  
Technical Specification ◽  
Shaking Table ◽  
Scale Model ◽  
Wall Structure ◽  
High Rise ◽  
Table Model ◽  
Shaking Table Model Test

A building developed by Wuhan Shimao Group in Wuhan, China, is a high-rise residence with 56 stories near the Yangtze River. The building is a reinforced concrete structure, featuring with a nonregular T-type plane and a height 179.6 m, which is out of the restrictions specified by the China Technical Specification for Concrete Structures of Tall Building (JGJ3-2010). To investigate its seismic performance, a shaking table test with a 1/30 scale model is carried out in Structural Laboratory in Wuhan University of Technology. The dynamic characteristics and the responses of the model subject to different seismic intensities are investigated via the analyzing of shaking table test data and the observed cracking pattern of the scaled model. Finite element analysis of the shaking table model is also established, and the results are coincident well with the test. An autoregressive method is also presented to identify the damage of the structure after suffering from different waves, and the results coincide well with the test and numerical simulation. The shaking table model test, numerical analysis, and damage identification prove that this building is well designed and can be safely put into use. Suggestions and measures to improve the seismic performance of structures are also presented.

Shaking Table Model Test for Vertical Seismic Response of Bent-Type Aqueduct

2010 ◽  
Vol 163-167 ◽  
pp. 4156-4164 ◽  
Author(s):  
Qiu Hua Duan ◽  
Meng Lin Lou
Keyword(s):  
Model Test ◽  
Seismic Waves ◽  
Dynamic Effect ◽  
Hydrodynamic Pressure ◽  
Shaking Table ◽  
Vertical Acceleration ◽  
Modal Damping ◽  
Earthquake Resistant Design ◽  
Table Model ◽  
Shaking Table Model Test

Based on the shaking table model test of a bent-type aqueduct on the rigidity foundation, the dynamic characteristics and seismic performance of the aqueduct structure subjected to vertical seismic waves are discussed. The test indicates that (1) Water in the aqueduct makes the mass of the structure larger and the frequency of the model structure lower. The water in aqueduct makes fundamental frequency of the model reduce 32% and the modal damping increase 38.5% averagely. (2)The hydrodynamic pressure response at the bottom of the aqueduct is the highest. (3)The dynamic effect of El waves on the aqueduct structure is greater than that of all SEW waves. (4) Different types of earthquake waves have different frequency spectrum characteristics, so that the aqueduct model responses differently to different waves. (5) The water in the aqueduct sometimes plays a role as TLD damping in certain scope. If surpassing this scope, the water sloshing makes the vertical acceleration response of the aqueduct increase. The results of the test not only lead to some significant conclusions for the earthquake-resistant design of large bent-type aqueducts, but also provide a ground for further studies on the effects of soil-pile-aqueduct interaction.

Dynamic Responses of RC Underground Subway Station and Soil during the Strong Earthquake

2011 ◽  
Vol 194-196 ◽  
pp. 2018-2023
Author(s):  
Jin Bian ◽  
Lian Jin Tao ◽  
Wen Pei Wang ◽  
Bo Zhang
Keyword(s):  
Underground Structure ◽  
Time History ◽  
Side Wall ◽  
Relative Displacement ◽  
Shaking Table ◽  
Dynamic Responses ◽  
Subway Station ◽  
Rc Structures ◽  
Underground Subway Station ◽  
Table Model

Underground subway RC structures suffered significant damage during many earthquakes, so it is important to study the seismic behavior on RC subway structure. The shaking table model test is made of the Beijing typical subway station structure. In this article, the test is introduced briefly; then, the acceleration history curves are analyzed. By the test, it is found that the interaction exits between structure and soil. Under the low intensity earthquake, the underground structure will exert a very small influence on soil and vibrates with soil; under the high intensity earthquake, the soil will exert a large thrust on the underground structure and the relative displacement exists between them. Moreover, At the bottom of the structure side wall, the peak acceleration is larger than it in soil around the place, and at the top and middle of the structure side wall, the peak accelerations are smaller than them in soil around the place; with the depth increase, decrease the peak value, the excellence frequency and its amplitude of the acceleration time history.

scholarly journals Shaking Table Test for Evaluating the Seismic Performance of Steel Frame Retrofitted by Buckling-Restrained Braces

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Tingting Wang ◽  
Jianhua Shao ◽  
Chao Zhao ◽  
Wenjin Liu ◽  
Zhanguang Wang
Keyword(s):  
Seismic Performance ◽  
Shear Force ◽  
Seismic Waves ◽  
Shaking Table Test ◽  
Steel Frame ◽  
Shaking Table ◽  
Frame Structure ◽  
Acceleration Response ◽  
Buckling Restrained Brace ◽  
Interstory Drift

To investigate the seismic performance of buckling-restrained braces under the earthquake action, the shaking table test with a two-story 1/4 scale model is carried out for the ordinary pure steel frame and the buckling-restrained bracing steel frame with low-yield-point steel as the core plate. The failure modes, dynamic characteristics, acceleration response, interstory drift ratio, strain, shear force, and other mechanical properties of those two comparative structures subjected to different levels of seismic waves are mainly evaluated by the experiment. The test results show that under the action of seismic waves with different intensities, the apparent observations of damage occur in the pure frame structure, while no obvious or serious damage in the steel members of BRB structure is observed. With the increase in loading peak acceleration for the earthquake waves, the natural frequency of both structures gradually decreases and the damping ratio gradually increases. At the end of the test, the stiffness degradation rate of the pure frame structure is 11.2%, while that of the buckling-restrained bracing steel frame structure is only 5.4%. The acceleration response of the buckling-restrained bracing steel frame is smaller than that of the pure steel frame, and the acceleration amplification factor at the second story is larger than that at the first story for both structures. The average interstory drift ratios are, respectively, 1/847 and 1/238 for the pure steel frame under the frequent earthquake and rare earthquake and are 1/3000 and 1/314 for the buckling-restrained bracing steel frame, which reveals that the reduction rate of lateral displacement reaches a maximum of 71.71% after the installation of buckling-restrained brace in the pure steel frame. The strain values at each measuring point of the structural beam and column gradually increase with the increase of the peak seismic acceleration, but the strain values of the pure steel frame are significantly larger than those of the buckling-restrained bracing steel frame, which indicates that the buckling-restrained brace as the first seismic line of defense in the structure can dramatically protect the significant structural members. The maximum shear force at each floor of the structure decreases with the increase in height, and the shear response of the pure frame is apparently higher than that of the buckling-restrained bracing structure.

Analysis of the Influence of Mortise-Tenon Joint Damage on Seismic Performance of Ancient Timber Structure

2014 ◽  
Vol 580-583 ◽  
pp. 1595-1599 ◽  
Author(s):  
Xue Liang Wang ◽  
Liang Jin
Keyword(s):  
Energy Dissipation ◽  
Seismic Performance ◽  
Joint Damage ◽  
Hysteresis Loops ◽  
Timber Structure ◽  
Dynamic Responses ◽  
Earthquake Intensity ◽  
Main Indicator ◽  
Before And After ◽  
Rare Earthquake

This research investigated the influence of mortise-tenon joint before and after damage on seismic performance of ancient lifted-beam timber structure. Dynamic responses of an ancient timber structure under various earthquake intensities were analyzed by ANSYS to extract the M-θ hysteresis loops of mortise-tenon joints before and after damage. The area of the largest hysteresis loop was taken as quantitative indicator to measure energy dissipation of mortise-tenon joints. The results shows that if some mortise-tenon joints were damaged, they dissipated much less earthquake energy decreasing by 31.8%-38.5%, and top displacement of structures increased by 1.79%-5.96% correspondingly. Moreover, the displacement under 8-degree-fortification, 7-degree-rare earthquake intensity increased most obviously. Therefore, energy dissipation of mortise-tenon joint is a main indicator to the assessment of seismic performance of a damaged ancient timber structure.

Recent Study on Seismic Performance and Response Control of Tall Buildings

2012 ◽  
Author(s):  
Xilin Lu ◽  
Huanjun Jiang
Keyword(s):  
Seismic Performance ◽  
Mainland China ◽  
Tall Buildings ◽  
Shaking Table ◽  
Wall Structure ◽  
Coupling Beams ◽  
Response Control ◽  
Rapid Economic Growth ◽  
Table Model ◽  
Performance Based Seismic Design

<p>As a result of rapid economic growth and urbanization, a huge amount of tall buildings have been constructed in Mainland China in the recent two decades. Tall buildings are the symbols of our industrialized societies and provide us more living and working spaces in the limited land. They have become one of the most important infrastructures in the renewal of our urban environment as well as the creation of new urban area throughout the world. However, tall buildings suffered serious damages during the past earthquakes. Some research and practice work of seismic performance and response control of tall buildings in Mainland China in recent years are introduced here, including the general methodologies for performance-based seismic design of tall buildings, shaking table model tests on complex tall buildings to evaluate the seismic performance of structures and accordingly revise the structural design, and a new type of earthquake resilient shear wall structure with replaceable coupling beams and replaceable foot parts.</p>

Pile Foundation Analysis of Ground Motion Transfer Law

2011 ◽  
Vol 368-373 ◽  
pp. 2915-2918
Author(s):  
Chun Yuan Liu ◽  
Dong Kun Sun ◽  
Ming Feng Han
Keyword(s):  
Pile Foundation ◽  
Seismic Waves ◽  
Programming Model ◽  
Shaking Table ◽  
Soil System ◽  
Measuring Point ◽  
Different Types ◽  
Table Model ◽  
Shaking Table Model Test ◽  
Matlab Programming

Based on shaking table model test, each response of the pipe models is obtained by inputting different types, amplitudes, frequencies of seismic waves and white noise excitation. The transfer function of the measuring point related to the vibration table, natural frequency of soil and pile, power spectrum and other parameters are obtained by Matlab programming model. By applicating SeismoSignal the propagation of seismic waves in the soil was gotten. Reveal the regulation of the propagation of the seismic waves in the pile-soil system. Investigate dynamic characteristics and dynamic response of the pile and soil in the earthquake and the transfer laws of the seismic wave energy. Provide a useful reference for the pile foundation seismic design.

scholarly journals Study on the Seismic Performance of Prefabricated Single-Segment Steel Jacket Bridge Piers

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2312
Author(s):  
Baodong Deng ◽  
Yanmin Jia ◽  
Dongwei Liang
Keyword(s):  
Seismic Performance ◽  
Shaking Table ◽  
Parameter Analysis ◽  
Dynamic Responses ◽  
Bridge Piers ◽  
Longitudinal Reinforcement ◽  
Anchorage Length ◽  
Single Segment ◽  
Steel Jacket ◽  
Bridge Models

To study the seismic performance of prefabricated single-segment steel jacket piers connected by grouting sleeves, two scaled symmetrical pier models with different anchorage lengths of the longitudinal reinforcement in the grouting sleeves and a comparative symmetrical cast-in-place (CIP) model were designed. OpenSees finite element models were established and shaking table tests were carried out on the three scaled pier models. The seismic response of each pier was compared and analyzed. Results showed the stiffness of the two prefabricated piers was greater than that of the CIP pier, and other seismic responses were less than those of the CIP piers, The dynamic responses of the two prefabricated bridge models were similar and changing the anchorage length of the reinforcement in the grouting sleeve had little effect on the seismic performance of the prefabricated pier. The simulation results were in good agreement with the experimental results. In the parameter analysis, the counterweight of the pier top had the greatest influence on the seismic performance of the prefabricated pier. The anchorage length of the longitudinal reinforcement in the grouting sleeve could be 6–14 times the diameter of the longitudinal reinforcement. Moreover, the seismic performance was found to be optimal when the thickness of the steel jacket was 5–7 mm.

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