Seismic design and hybrid tests of a full‐scale three‐story buckling‐restrained braced frame using welded end connections and thin profile     

Pao‐Chun Lin  Keh‐Chyuan Tsai  Kung‐Juin Wang  Yi‐Jer Yu  Chih‐Yu Wei  An‐Chien Wu  Ching‐Yi Tsai  Chih‐Han Lin  Jia‐Chian Chen  Andreas H. Schellenberg  Stephen A. Mahin  Charles W. Roeder 《地震工程与结构动力学》2012,41(5):1001-1020

A series of hybrid and cyclic loading tests were conducted on a three‐story single‐bay full‐scale buckling‐restrained braced frame (BRBF) at the Taiwan National Center for Research on Earthquake Engineering in 2010. Six buckling‐restrained braces (BRBs) including two thin BRBs and four end‐slotted BRBs, all using welded end connection details, were installed in the frame specimen. The BRBF was designed to sustain a design basis earthquake in Los Angeles. In the first hybrid test, the maximum inter‐story drift reached nearly 0.030 rad in the second story and one of the thin BRBs in the first story locally bulged and fractured subsequently before the test ended. After replacing the BRBs in the first story with a new pair, a second hybrid test with the same but reversed direction ground motion was applied. The maximum inter‐story drifts reached more than 0.030 rad and some cracks were found on the gusset welds in the second story. The frame responses were satisfactorily predicted by both OpenSees and PISA3D analytical models. The cyclic loading test with triangular lateral force distribution was conducted right after the second hybrid test. The maximum inter‐story drift reached 0.032, 0.031, and 0.008 rad for the first to the third story, respectively. This paper then presents the findings on the local bulging failure of the steel casing by using cyclic test results of two thin BRB specimens. It is found that the steel casing bulging resistance can be computed from an equivalent beam model constructed from the steel core plate width and restraining concrete thickness. This paper concludes with the recommendations on the seismic design of thin BRB steel casings against local bulging failure. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Cyclic test of a coupled steel plate shear wall substructure     

Chao‐Hsien Li  Keh‐Chyuan Tsai  Jing‐Tang Chang  Chih‐Han Lin  Jia‐Chian Chen  Te‐Hung Lin  Pei‐Ching Chen 《地震工程与结构动力学》2012,41(9):1277-1299

Coupled steel plate shear wall (C‐SPSW) consists of two or more steel plate shear walls interconnected by coupling beams at the floor levels. In this study, a six‐story C‐SPSW prototype building was designed. A 40% scale C‐SPSW specimen, which is representative of the bottom two‐and‐half‐story substructure of the prototype, was cyclically tested using Multi‐Axial Testing System at the National Center for Research on Earthquake Engineering in 2009. In addition to a constant vertical force representing the gravity load effects, cyclic increasing displacements and the corresponding overturning moments transmitted from the upper stories were computed online and simultaneously applied on the substructural specimen. This paper firstly introduces the designs of the prototype C‐SPSW and the test specimen. Then, the test results and the numerical simulation are discussed in detail. Test results confirm the effectiveness of the proposed column capacity design method, which aims at limiting the plastic hinge formation within the bottom quarter height of the bottom column. Test and analytical results suggest that the coupling beam rotational demands can be estimated as the design story drifts when the formation of desirable plastic mechanism of the C‐SPSW is expected. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Real‐time hybrid testing of a smart base isolation system          下载免费PDF全文

Pei‐Ching Chen  Keh‐Chyuan Tsai  Pei‐Yang Lin 《地震工程与结构动力学》2014,43(1):139-158

Real‐time hybrid testing is a very effective technique for evaluating the dynamic responses of rate‐dependent structural systems subjected to earthquake excitation. A smart base isolation system has been proposed by others using conventional low‐damping isolators and controllable damping devices such as magnetorheological (MR) dampers to achieve specified control target performance. In this paper, real‐time hybrid tests of a smart base isolation system are conducted. The simulation is for a base‐isolated two‐degrees‐of‐freedom building model where the superstructure and the low‐damping base isolator are numerically simulated, and the MR damper is physically tested. The target displacement obtained from the step‐by‐step integration of the numerical substructure is imposed on the MR damper, which is driven by three different control algorithms in real‐time. To compensate the actuator delay and improve the accuracy of the test, an adaptive phase‐lead compensator is implemented. The accuracy of each test is investigated by using the root mean square error and the tracking indicator. Experimental results demonstrate that the hybrid testing procedure using the proposed actuator compensation techniques is effective for investigating the control performance of the MR damper in a smart base isolation system. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Uncertainty Estimation in One‐Dimensional Heat Transport Model for Heterogeneous Porous Medium     

Ching‐Min Chang  Hund‐Der Yeh 《Ground water》2014,52(3):326-331

In many practical applications, the rates for ground water recharge and discharge are determined based on the analytical solution developed by Bredehoeft and Papadopulos (1965) to the one‐dimensional steady‐state heat transport equation. Groundwater flow processes are affected by the heterogeneity of subsurface systems; yet, the details of which cannot be anticipated precisely. There exists a great deal of uncertainty (variability) associated with the application of Bredehoeft and Papadopulos' solution (1965) to the field‐scale heat transport problems. However, the quantification of uncertainty involved in such application has so far not been addressed, which is the objective of this wok. In addition, the influence of the statistical properties of log hydraulic conductivity field on the variability in temperature field in a heterogeneous aquifer is also investigated. The results of the analysis demonstrate that the variability (or uncertainty) in the temperature field increases with the correlation scale of the log hydraulic conductivity covariance function and the variability of temperature field also depends positively on the position.  相似文献   

Discrete element method for bearing capacity analysis     

Ching S. Chang  Sao-Jeng Chao 《Computers and Geotechnics》1991,12(4):273-288

Analysis based on Discrete Element Method (DEM) is presented for estimating bearing capacity of foundations. Soil mass in the present model is treated as comprising of blocks which are connected by elasto-plastic Winkler-springs. By considering the conditions of compatibility, the boundary stresses on the failure surface and the ultimate bearing capacity of shallow foundations can be obtained. The computed boundary stresses from the present method satisfy equilibrium conditions and do not exceed the material strength. Formulation of the method is presented. Examples are shown to demonstrate the applicability of the method to the analysis of bearing capacity of shallow foundations. Effects of stiffness of Winkler-springs and mesh pattern on the computed results are investigated. The present method is shown to be a useful tool for analyzing bearing capacity of foundations with unusual geometry and loading conditions.  相似文献   

Evaluation of an anisotropic elastoplastic–viscoplastic bounding surface model for clays     

Jianhong Jiang  Hoe I. Ling  Victor N. Kaliakin  Xiangyong Zeng  Ching Hung 《Acta Geotechnica》2017,12(2):335-348

An anisotropic time-dependent bounding surface model for clays is developed by generalizing a previous time-independent model that adopts a flexible bounding surface. It is based on the framework for coupled elastoplasticity–viscoplasticity for clays and Perzyna’s overstress theory. Three viscoplastic parameters were introduced and explained in detail. The model was validated against undrained creep tests for both isotropically and anisotropically consolidated clays, undrained and drained stress relaxation tests on some undisturbed clays, and undrained triaxial tests with varying strain rates on natural Hong Kong marine deposit clay. The general agreement between the model simulations and test results was satisfactory. The varying effects of lower-level parameters were discussed on the undrained multistage stress relaxation response for normally consolidated soils which had been ignored in literature. The flexibility of the model in capturing the shear strengths, which is the unique feature of the current model, was shown in the simulations of time-dependent triaxial tests on Taipei silty clay. All the simulations show that the proposed model is a relatively practical model considering both anisotropy and time dependency of clays.  相似文献   

A compression model for sand–silt mixtures based on the concept of active and inactive voids     

Ching S. Chang  Mehrashk Meidani  Yibing Deng 《Acta Geotechnica》2017,12(6):1301-1317

A compression model for sand–silt mixtures is needed in geotechnical engineering, for example in the analysis and prediction of deformation of levees and embankments due to internal erosion. In this paper, we introduce a novel concept of dividing the voids of a granular material into two hypothetical fractions: active and inactive voids. The active voids are kinematically available to the compression process. The inactive voids are kinematically unavailable to the compression process. The volume of active voids is dependent on the initial density and effective stress level. The volume of inactive voids is dependent on the amount of fines in the mixture. The current paper considers 1-D and isotropic compression behavior of sand–silt mixtures at stress levels lower than 2 MPa, so no substantial particle breakage is expected to occur. To successfully predict the void ratio for a sand–silt mixture during compression loading, we need (1) a mathematical expression for the evolution of the active void ratio during compression and (2) a relationship between the inactive void ratio and fines content of the mixture. For sand–silt mixtures with any amount of fines, the proposed model requires five material parameters, which are determined from two compression tests, and four minimum void ratio tests on sand–silt mixtures with different fines content. The performance of the proposed model is verified for six different types of sand–silt mixture with various fines contents, by comparing the predicted void ratios with the measured data from the experiments. The comparisons show a good agreement between the predictions and the measured data and prove the suitability of the proposed model for the prediction of compressibility of sand–silt mixtures with any amount of fines.  相似文献   

Pressure‐dependent elastic moduli of granular assemblies     

Ching L. Liao  Tian C. Chan  Akke S. J. Suiker  Ching S. Chang 《国际地质力学数值与分析法杂志》2000,24(3):265-279

  相似文献