Suitability of Bi-linear Restoring Force Model in Earthquake Response Analysis

Based on the data of dynamic tests of small single-storey steel frames,the suitability of simplified hi-linear restoring force model in earthquake response analysis is discussed, and the Maximum displacement response MD, the sum of squares of the displacements in the whole vibrating history SSD, and the total dissipated energy EI are considered respectively as equivalent object.     

基于岭回归模型的农村剩余劳动力转移影响因素分析

为更好的解释农村剩余劳动力转移的影响因素,在国内外农村剩余劳动力研究的基础上,笔者运用定性和定量相结合的分析方法进行分析。为避免多重共线性在模型中的影响,采用岭回归模型对相应影响变量进行分析。通过模型综合分析,验证了影响中国农村剩余劳动力转移的推动因素和制约因素。同时提出发展区域经济,提高农民收入;推进城镇化进程,拓宽农民就业渠道;促进二、三产业发展转型与加强农民专业培训齐头并进;深化以户籍制度为中心的制度变革等4项政策建议。     

Strut and Tie Model Method of ReinforcedConcrete Beam Column Joint Core

“Macro model” in OPENSEES is an ideal and effective method for simulating RC beam column joint. Some disadvantages, however, exist in both the modified compression field theory (MCFT) and diagonal compression strut model, with which they are commonly used to obtain the shear stress strain relation of joint core. A new method by means of strut and tie model (STM), which reflected three mechanisms in joint well, was proposed to simulate the shear stress strain response of joint core. The deformation compatibility and equilibrium condition of the model were deduced thereafter. It was indicated that the result of STM method was in good agreement with that of test data. And it could simulate more accurately the shear stress strain response of joint core with a wide range of stirrup ratio.     

Nonlinear Finite Element Analysis of RC Deep Flexural Simply Supported Beams Using Disturbed Stress Field Model

A nonlinear finite element analysis of 4 RC deep flexural simply supported beams with the program VT2 is presented. Crack development and failure modes , longitudinal reinforcement strain distributions and load -deflection curves were compared as a result in order to evaluate the validity of the disturbed stress field model to analyse such deep simply supported beam.