Retraining local and global buckling behavior of steel plastic hinges using CFRP

Carbon fiber-reinforced polymer (CFRP) composites have been shown to be particularly well suited for external strengthening of reinforced concrete members. However, there is limited information about how they can be used to strengthen steel structures that are susceptible to local and global instabilities. This paper discusses test results of full-scale steel flexural specimens subjected to reversed cyclic loading, some of which are wrapped with CFRP in the plastic hinge region. The main variables investigated are lateral bracing, to study the effect of CFRP wrapping on local buckling and lateral torsional buckling, wrapping scheme, and number of layers of fibers. The test results show that application of CFRP in the plastic hinge region of flexural members has substantial benefits. In particular, the CFRP wraps can increase the size of the yielded plastic hinge region, slow down the occurrence of local buckling, and delay lateral torsional buckling. These benefits reduce strain demands in the critical plastic hinge region and substantially improve energy dissipation capacity within the plastic hinge region.     

市政排水管网系统的研究与开发

目前排水管网水力计算只是一种代替手工计算、查表等一系列繁琐、重复的管线计算程序,不能满足整个管网自动化、智能化计算的需要。结合图论原理,以排水管网为对象,采取广度优先算法,开发出管网自动识别系统,应用到主次管线的自动搜索、任意节点汇水面积的自动化计算。这对于减少管网水力计算的工作量具有突破性的作用。     

等截面连续受压直杆临界荷载的求解

利用材料力学、常微分方程及行列式知识,求解了连续受压杆率曲微分方程,计算了不同长度组合受压杆的整体临界荷载及计算长度系数,与钢结构设计中所采用的计算长度系数进行了对比分析。     

Local buckling of steel plates in concrete-filled thin-walled steel tubular beam-columns

The availability of high strength steels and concrete leads to the use of thin steel plates in concrete-filled steel tubular beam-columns. However, the use of thin steel plates in composite beam-columns gives a rise to local buckling that would appreciably reduce the strength and ductility performance of the members. This paper studies the critical local and post-local buckling behavior of steel plates in concrete-filled thin-walled steel tubular beam-columns by using the finite element analysis method. Geometric and material nonlinear analyses are performed to investigate the critical local and post-local buckling strengths of steel plates under compression and in-plane bending. Initial geometric imperfections and residual stresses presented in steel plates, material yielding and strain hardening are taken into account in the nonlinear analysis. Based on the results obtained from the nonlinear finite element analyses, a set of design formulas are proposed for determining the critical local buckling and ultimate strengths of steel plates in concrete-filled steel tubular beam-columns. In addition, effective width formulas are developed for the ultimate strength design of clamped steel plates under non-uniform compression. The accuracy of the proposed design formulas is established by comparisons with available solutions. The proposed design formulas can be used directly in the design of composite beam-columns and adopted in the advanced analysis of concrete-filled thin-walled steel tubular beam-columns to account for local buckling effects.     

丽江白沙乡龙泉行政村民居及其环境研究

束河村是纳西族最早聚居地之一，研究束河村民居及其环境的现状，对改善那里的民居及环境有重要的意义，该文对该村不同地形，不同材料的民居及环境作了研究，并做了实地实测。     

基于地域文化语汇的空间规划与设计研究

在全球化过程中,中国特色的目标实现需要地域化具体实施,顺延"地域文化--空间语汇--空间形态"的逻辑,描述、分析地域城市发展过程中的"泛文化"现象,澄清城市空间设计的地域文化观念问题,探讨基于空间句法的地域城市空间的规划设计方法.     

A simplified method for elastic large deflection analysis of plates and stiffened panels due to local buckling

A computational model for analysis of local buckling and postbuckling of stiffened panels is derived. The model provides a tool that is more accurate than existing design codes, and more efficient than nonlinear finite element methods. Any combination of biaxial in-plane compression or tension, shear, and lateral pressure may be analysed. Deflections are assumed in the form of trigonometric function series. The deformations are coupled such that continuity of rotation between the plate and the stiffener web is ensured, as well as longitudinal continuity of displacement. The response history is traced using energy principles and perturbation theory. The procedure is semi-analytical in the sense that all energy formulations are derived analytically, while a numerical method is used for solving the resulting set of equations, and for incrementation of the solution. The stress in certain critical points are checked using the von Mises yield criterion, and the onset of yielding is taken as an estimate of ultimate strength for design purposes.     

索穹顶结构的优化设计

索穹顶结构优化设计分为三个方面 :预应力优化设计、截面优化设计、形状优化设计。通过线性规划、齿形法及模态搜索法的联合应用 ,内力分析采用有限单元法 ,预应力优化设计采用线性规划法 ,截面优化设计采用齿形法 ,形状优化设计采用模式搜索法 ,编制了索穹顶结构优化的计算程序 ,将索穹顶结构优化设计的三个方面有机地结合在一起 ,进行了循环迭代求解     

当代建筑结构体系中的技术表现分析

建筑技术的发展一直伴随着建筑艺术的发展,当代建筑结构技术也成为了建筑表现的重要因素之一,其在满足建筑形式和功能要求的同时,开始更多地关注哲学思想、人文情感和环境意识的表达.该文分析和总结了当代建筑结构技术在建筑表现中的运用和发展趋势,希望这样的分析与归纳对建筑实践有一定的参考意义.     

承载乡土基因的旅游生态聚落空间——以云南丘北县普者黑镇彝族旅游小镇规划为例

"青绿山水,重彩彝居"的特色资源使云南丘北县普者黑彝族小镇的旅游开发获得了经济效益,但旅游业的发展也带来了传统聚落风貌受到严重损害等不良后果.规划以"乡土意"为理念,对当地彝居原型进行分析、提炼,对材料工艺进行改造,预设多种"新型彝居"和公共服务设施的营构方式,以正确引导民居改建;规划还将山体作为空间轴线的重要组成部分,将水体引入小镇,并对水岸进行柔化处理,使聚落因水而建.