Approximate Methods for Estimating Hysteretic Energy Demand on Plan-Asymmetric Buildings

The first step in a hysteretic energy-based design approach of performance-based design is the estimation of hysteretic energy demand in the structure. A nonlinear response-history analysis of the multi-degree of freedom model gives an accurate estimation, but it is not suitable for adopting in design. Two alternative methods, based on the concepts of modal pushover analysis (MPA) and 2D-MPA, are proposed in this article for uniaxial plan-asymmetric structures. Application studies show that both methods are efficient. While the 2D-MPA-based method is more accurate, the MPA-based method is more suitable for design adoption. Significant conclusions are given for prospective application of these methods.     

Flexural and Shear Damage Models for MRF Structures Excited by Far-Field Horizontal Strong Ground Motions

The unexpected damages in structures during severe earthquakes have been reported frequently so far. In this study, the damage-based inelastic behavior of special moment resisting frame (SMRF) structures designed according to the new versions of general earthquake loading codes (International building code [IBC] 2012 & American Society of Civil Engineers [ASCE] 7-2010) and seismic design references (National Earthquake Hazards Reduction Program [NEHRP] 2009 & Federal Emergency Management Agency [FEMA] P-750) has been investigated. The final results presented based on distinctive shear and flexural failure modes show that a non-uniform distribution of severe damage in structural height occurs during design level seismic excitations. Also it is observed that the shear and flexural damages are more critical in short and tall MRF structures, respectively.     

Development and Verification of a New Site Classification System and Site Coefficients for Regions of Shallow Bedrock in Korea

In this article, site response analyses for 124 sites collected in Korea were performed to evaluate earthquake ground motions in regions of shallow bedrock in Korea. Based on the results, a new two-parameter site classification system was developed for use in regions of shallow bedrock. The system incorporates depth to bedrock and mean V_S of soil above bedrock as parameters for site classification instead of V_S30. Soil sites were divided into seven site classes and the corresponding site coefficients were proposed for each site category. Some verification work demonstrates the superiority of the proposed system over the current seismic codes.     

Effective Stiffness of Non-Rectangular Reinforced Concrete Structural Walls

The effective stiffness of a structural wall is an important property in design, which many design codes estimate by the moment inertia of the wall section with a reduction factor. The reduction factor is typically estimated by empirical equations based on configurations of the wall. The existing methods for the reduction factor were proposed based on investigations on rectangular reinforced concrete (RC) walls. The effective stiffness of non-rectangular RC walls can be more complex than that of rectangular RC walls. As such, more research investigations are required. Based on finite element models, the effective stiffness of U-shaped and T-shaped RC walls was investigated in this paper. The numerical results were further adopted to develop methods for calculating the effective stiffness of non-rectangular wall in different loading directions. The proposed method was afterward compared with the experimental data.     

Experimental Study on Seismic Performance of Mechanical/Electrical Equipment with Vibration Isolation Systems

A prototype diesel generator equipped with a vibration isolation system consisting of restrained isolators (denoted as I/system) is quasi-statically and dynamically tested. Sequentially, the seismic simulation tests are conducted to further investigate the effectiveness of additional snubbers incorporated into the vibration isolation system (denoted as I/R system). Comparing the test results to the static design demands specified in ASCE 7-10, the recommended component amplification factor could represent the horizontal acceleration amplification phenomenon of the generator equipped with I/R system; however, the seismic force demands for static design of I/R system might not be appropriate and conservative enough.     

高校人才流动原因及对策探析

近年来,高校人才流动频繁已成为制约高校发展的瓶颈和高校人事管理一大难题。运用马斯洛需要层次理论,探析高校人才流动的原因,并提出相关对策。     

先秦时期瓦当中的兽面纹与人面纹

兽面纹与人面纹是先秦时期非常有特点的瓦当图案。本文通过对兽面纹的来源、分类及兽面纹与其他瓦当图案组合的研究,阐明了兽面纹演变过程中的简化规律。并通过分析兽面纹与抽象人面纹的异同点,以及二者在发展演变规律上的一致性,论证了抽象人面纹与兽面纹之间的承继关系及这种变化与当时历史背景的关系。     

Experimental Study on the Seismic Performance of Superimposed RC Shear Walls with Enhanced Horizontal Joints

The seismic performance of superimposed reinforced concrete (RC) shear walls is decreased by rocking behavior and damage concentration at the horizontal joint. An enhanced horizontal joint method is proposed to improve the corresponding seismic performance. To validate the reliability of the proposed method, three full-scale superimposed walls and a cast-in-place shear wall (for comparison) are designed and tested under the quasi-static load. The test results indicate that the rocking phenomenon can be prevented using the proposed method, and the seismic performance of superimposed RC shear walls with enhanced horizontal joints is comparable to that of the cast-in-place RC shear walls.