scholarly journals Laboratory Tests for Subgrade Reaction Coefficient in Seismic Design of Underground Engineering Domain

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Kunpeng Xu ◽  
Liping Jing ◽  
Xinjun Cheng ◽  
Haian Liang ◽  
Jia Bin
Keyword(s):  
Seismic Design ◽  
Shaking Table Test ◽  
Free Field ◽  
Deformation Mode ◽  
Shaking Table ◽  
Subgrade Reaction ◽  
Underground Structures ◽  
Testing Methods ◽  
Underground Engineering ◽  
Reaction Coefficient

Subgrade reaction coefficient is commonly considered as the primary challenge in simplified seismic design of underground structures. Carrying out test is the most reliable way to acquire this intrinsic soil property. Owing to the limitations of experimental cost, time consumption, soil deformation mode, size effect, and confined condition, the existing testing methods cannot satisfy the requirements of high-precision subgrade reaction coefficient in seismic design process of underground structures. Accordingly, the present study makes an attempt to provide new laboratory testing methods considering realistic seismic response of soil, based on shaking table test and quasistatic test. Conventional shaking table test for sandy free-field was performed, with the results indicating that the equivalent normal subgrade reaction coefficients derived from the experimental hysteretic curves are reasonable and verifying the deformation mode under seismic excitation. A novel multifunctional quasistatic pushover device was invented, which can simulate the most unfavorable deformation mode of soil during the earthquake. In addition, the first successful application of an innovative quasistatic testing method in evaluating subgrade reaction coefficient was reported. The findings of this study provide preliminary detailed insights into subgrade reaction coefficient evaluation which can benefit seismic design of underground structures.

Simple approach to obtain ground amplification motion of surface soil deposits with a radical change of depth

2005 ◽  
Vol 42 (2) ◽  
pp. 491-498
Author(s):  
Dae-Sang Kim ◽  
Kazuo Konagai
Keyword(s):  
Seismic Design ◽  
Surface Soil ◽  
Underground Structure ◽  
Free Field ◽  
Alluvial Soil ◽  
Radical Change ◽  
Simple Approach ◽  
Clear Understanding ◽  
Underground Structures ◽  
Soil Deposits

Earthquake observations at different sites within alluvial soil deposits have demonstrated that the motion of buried underground structures closely follows that of the surrounding soil. Therefore, it is usual in a seismic design process to apply free-field ground displacements through Winkler-type soil springs to an underground structure to evaluate stress patterns induced within its structural members. Using a simplified approach, this paper provides a clear understanding of resonant horizontal ground displacement of and strain in a surface soil deposit with a radical change of depth and of where they occur.Key words: simple approach, seismic design, earthquake, resonance, underground structures.

scholarly journals Multi-point shaking table test of the free field under non-uniform earthquake excitation

2015 ◽  
Vol 55 (5) ◽  
pp. 985-1000 ◽  
Author(s):  
Xiao Yan ◽  
Haitao Yu ◽  
Yong Yuan ◽  
Juyun Yuan
Keyword(s):  
Shaking Table Test ◽  
Free Field ◽  
Shaking Table ◽  
Earthquake Excitation

Shaking Table Test on Unreinforced Stone Masonry Pagoda

2012 ◽  
Vol 166-169 ◽  
pp. 730-733 ◽  
Author(s):  
Fei Zhu ◽  
Feng Lai Wang ◽  
Xu Jie Sun ◽  
Y. Zhao
Keyword(s):  
Dynamic Behavior ◽  
Seismic Performance ◽  
Seismic Design ◽  
Shaking Table Test ◽  
Shaking Table ◽  
Cultural Value ◽  
Scale Model ◽  
Stone Masonry ◽  
Experimental Program ◽  
Ancient China

Unreinforced stone masonry pagodas have great cultural value and should be detailed investigation its mechanical properties. These buildings were not designed to resist earthquakes in ancient China, at least not in the way of current methods. The objectives of this research were to understand the dynamic behavior of unreinforced stone masonry pagoda and its seismic performance. To accomplish these, a 1/12 scale model of China Dinosaurs Pagoda was constructed and tested on shaking table. The octangle model height is 3.96m, with aspect ratio of height to width is 2.93, both parameters exceed the stipulated limit of Code for Seismic Design of Building. The model built with the stones and motars similar to the prototype materials and the arrangements. Its dynamic behavior and seismic performance were tested on the shaking table towards the free vibration and three earthquake waves. The experimental program adopted in the research is explained in this paper.

Shaking Table Test of Muti-Story Subway Station Considering Soil-Structure Interaction

2013 ◽  
Vol 694-697 ◽  
pp. 321-324 ◽  
Author(s):  
Shu Wei Wang ◽  
Ying Ming Zhou ◽  
Shu Yun Mi
Keyword(s):  
Seismic Waves ◽  
Shaking Table Test ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Soil Surface ◽  
Shaking Table ◽  
Subway Station ◽  
Acceleration Process ◽  
Underground Structures

In this paper, a three-dimensional shaking table test of three three-span subway station model is done. Three test seismic waves were selected in this experiment, which were applied to the model. Modal analysis of the structure was done, and the determination of the acceleration of the model structure was obtained. And the law of underground structures under earthquake damage was analysis. Soil surface acceleration process and its response spectrum and strain are obtained in the different amplitudes of ground motion input case. From experiment cracks in the emergence and development of the situation were observed, and which gives recommendations for the seismic design of underground structures.

Experimental Study on the Seismic Response of Subway Station in Soft Ground

2017 ◽  
Vol 11 (05) ◽  
pp. 1750020 ◽  
Author(s):  
Ma Xianfeng ◽  
Wang Guobo ◽  
Wu Jun ◽  
Ji Qianqian
Keyword(s):  
Seismic Response ◽  
Seismic Design ◽  
Shaking Table Test ◽  
Design Method ◽  
Underground Structure ◽  
Response Characteristic ◽  
Shaking Table ◽  
Subway Station ◽  
Soft Ground ◽  
Shaking Table Tests

Shaking table tests were conducted on typical models of subway structures subjected to several seismic shaking time histories to study seismic response of subway structures in soft ground as well as to provide data for validation of seismic design methods for underground structure. Three types of tests were presented herein, namely green field test, subway station test, and test for joint structure between subway station and tunnel. The similitude and modeling aspects of the 1g shaking table test are discussed. The seismic response of Shanghai clay in different depths was examined under different input waves to understand the acceleration amplification feature in both green field and in the presence of underground structure. Damage situation was checked on internal sections of both subway station and tunnels by halving the model structure. Structure deformation was investigated in terms of element strain under different earthquake loadings. The findings from this study provides useful pointers for future shaking table tests on underground structures/facilities, and the seismic response characteristic of underground structure derived from the shaking table test could be helpful for validating seismic design method for subway station.

Shaking Table Test Study on Seismic Performance Improvement for Underground Structures with Center Column Enhancement

2019 ◽  
Vol 13 (02) ◽  
pp. 1950009 ◽  
Author(s):  
Cuizhou Yue ◽  
Yonglai Zheng ◽  
Shuxin Deng
Keyword(s):  
Carbon Fiber ◽  
Shaking Table Test ◽  
Underground Structure ◽  
Single Layer ◽  
Shaking Table ◽  
Seismic Resistance ◽  
Deformation Analysis ◽  
Underground Structures ◽  
Structure Deformation ◽  
Carbon Fiber Cloth

Central columns have long been demonstrated to play a vital role in withstanding not only static gravity loads but also seismic loads like earthquakes. A series of modeling tests are implemented on shaking table instrument to reflect the mechanism of soil — structure interaction and examine the validity of method of uplifting underground structural seismic resistance through strengthening central columns. An innovative method of enhancing central columns by adhering carbon fiber cloth onto column’s peripheral surface is introduced into a series of shaking table modeling tests, in which two two-layer underground model structures are constructed for comparison, one without any column remedy acts as a benchmark for reference and the other is amended with carbon fiber cloth adhered on column surface. Test results show that soft round model box adopted in tests serves well in simulating earthquake actions with negligible boundary effects on wave transfer; soil dynamic characteristics and the relative stiffness of structure to surrounding soil will interactively limit mutual motion and deformation. Racking deformation assumption may be not applicable for overall two-layer underground structure deformation analysis, but may be suitable for inter-layer displacement calculation for single layer in multi-layer rectangular underground structures. The adopted column enhancement measure could not only greatly increase the stiffness ratio of model structure to soil, reducing structure deformation, but also improve the integrity of underground structure by narrowing down the deformation difference between two structural layers, certifying that such a measure could be validly used in improving the seismic resistance capacity for already built underground structures without enough aseismic consideration when designed.

scholarly journals Shaking Table Test and Numerical Verification for Free Ground Seismic Response of Saturated Soft Soil

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Xuelei Cheng ◽  
Chunyi Cui ◽  
Zongguang Sun ◽  
Jinhong Xia ◽  
Guangbing Wang
Keyword(s):  
Numerical Simulation ◽  
Seismic Response ◽  
Effective Stress ◽  
Shaking Table Test ◽  
Soft Soil ◽  
Pressure Ratio ◽  
Free Field ◽  
Shaking Table ◽  
Response Characteristics ◽  
Fully Coupled

This paper investigates shaking table test (1g) and numerical simulation (fully coupled) of vertically propagating shear waves for saturated soft free field. A large-scale shaking table model test was performed to study seismic response characteristics of saturated soft soil free field. According to test results of seismic response features of free field system in saturated soft soil, the free field nonlinearity fully coupled numerical model of dynamical effective stress of saturated soft soil was established using OpenSEES, based on the u-p formulations of dynamic consolidation equation as well as effective stress solution method for saturated two-phase media. The numerical simulation of the free field seismic response of saturated soft soil under various test conditions was performed and the calculated results were compared with the shaking table test results. The results show the following. (1) With the increase of input ground motion intensity, the characteristic frequency of the saturated soft free ground decreases and the damping ratio increases gradually. (2) The saturated soft soil ground has short period filtering and long period amplification effect on the horizontal input seismic loads. The failure foundation takes on the isolation and shock absorption under strong ground motions. (3) The peak pore pressure ratio of the saturated soft soil ground is located in the shallow buried soil layer, and with the increase of the input ground motion intensity, the advantage of dynamic pore pressure ratio in this area is gradually weakened. (4) The numerical simulation results are consistent with the results of the shaking table test. This fully coupled effective stress numerical method can reasonably simulate the seismic response characteristics of free field in saturated soft soil, which lay the foundation for other more complex parameter extrapolation models of saturated soft soil sites. This research can provide the necessary technical experience for experimental study on non-free field.

Shaking Table Test to Underground Structures in Layered Foundation

2013 ◽  
Vol 353-356 ◽  
pp. 1461-1465
Author(s):  
Wei Feng Sun ◽  
Li Ping Jing ◽  
Yan Zou ◽  
Ning Bo Yang ◽  
Yong Qiang Li
Keyword(s):  
Sandy Soil ◽  
Shaking Table Test ◽  
Underground Structure ◽  
Soil Layer ◽  
Damage Mechanism ◽  
Shaking Table ◽  
Silty Clay ◽  
Test Model ◽  
Underground Structures ◽  
Similarity Ratio

A three-story underground structure shaking table test had been carried on to study the earthquake damage mechanism of underground structure in layered foundation. The test model was similar to typical subway station according to a certain similarity ratio, and the soils were disturbed sandy soil and silty clay dug from the site of Harbin subway. Shaking table tests to this typical model in silty clay and alternating layers of clay and sand were performed to reveal the effect of different layered soils. Results show that the sandy soil layer can reduce the damage of the soil and underground structure, the damage of underground structure is mainly controlled by displacement of the surrounding soil, and the response of shallow buried underground structure is larger than deep buried.

scholarly journals Performance Evaluation of Rigid Braced Indirect Suspended Ceiling with Steel Panels

2021 ◽  
Vol 11 (5) ◽  
pp. 1986
Author(s):  
Jae-Sub Lee ◽  
Dam-I Jung ◽  
Doo-Yong Lee ◽  
Bong-Ho Cho
Keyword(s):  
United States ◽  
Seismic Design ◽  
Shaking Table Test ◽  
The United States ◽  
Shaking Table ◽  
Personal Injury ◽  
Safety Standard ◽  
Design Standards ◽  
Design Life ◽  
Steel Panels

In Korea, the earthquakes in Gyeongju (2016) and Pohang (2017) have led to increased interest in the seismic design of nonstructural elements. Among these, the suspended ceiling can cause personal injury and property damage. In addition, most suspended ceilings that are used in Korea neither have seismic design details nor meet the current seismic design standards. There are two seismic design methods for suspended ceilings using a perimeter clip and a brace. In the United States and Japan, seismic design of ceilings is typically used, but the concepts of applying and installing braces are different. This is because the typical ceiling systems are different in the United States and Japan. In this study, a brace-applied ceiling system that is suitable for a suspended ceiling with a steel panel was applied in the indirect suspended ceiling mainly used in Korea. In addition, the seismic performance was verified through a shaking table test. All the specimens were applied with anti-falling clips that are designed to prevent the panels from falling, and they satisfy KDS 41 17 00, which is a Korean seismic design life safety standard. Without considering these factors, the performance level is lower than a nonseismic designed ceiling, which is not properly designed or constructed.

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