波浪腹板H型钢结构设计软件的研发与应用

波浪腹板H型钢是一类腹板为正弦曲线的型钢构件,具有承载效率高、经济性好等优点,多用于轻型门式刚架结构中。本文介绍了钢结构设计软件STS中波浪腹板H型钢结构设计功能,通过实例分析,比较波浪腹板与平腹板构件用于门式刚架、吊车梁设计中的用钢量,给出波浪腹板的经济性指标。     

波浪腹板门式刚架轻型房屋钢结构设计理论及应用

波浪腹板工形截面构件由翼缘与波浪腹板组成,与平腹板工形截面构件相比具有较高的承载效率。由波浪腹板工形截面构件所组成的门式刚架,在国外工业建筑轻型房屋钢结构工程中有较广泛的应用,其经济效益也明显优于传统的门式刚架结构。总结了笔者对波浪腹板工形截面构件在轴力、弯矩以及压弯组合作用下的受力性能与设计方法的研究成果,并与同类型平腹板的工形截面构件的性能与设计方法进行了比较。介绍了波浪腹板门式刚架的节点构造,并给出了波浪腹板工形构件的制作等方面的要求。比较了波浪腹板构件与平腹板构件的承载效率,并结合一个典型的门式刚架工业厂房,比较了波浪腹板门式刚架体系与平腹板门式刚架体系在经济性等方面的差异。     

基于极限承载力平面屈曲约束支撑钢框架整体可靠度设计

以最简形式的功能函数描述平面屈曲约束支撑钢框架在静力荷载作用下的体系极限承载力状态,利用对偶变数抽样法与指数多项式近似概率密度法对结构整体抗力的概率密度函数及其统计特征进行了估计。考虑两种基本荷载组合,在对平面屈曲约束支撑钢框架结构整体可靠度评价的基础上,给出了在一定目标可靠度下的基于结构体系极限承载力可靠度的实用设计公式。通过一个具体算例表明,该设计方法既比传统的基于构件可靠度的设计方法经济,又能保证结构体系的可靠度。     

门式刚架加固的简化内力计算方法

门式刚架作为一种特殊的轻型结构形式,在实际工程中得到广泛的应用,对于一些已经建成的门式刚架钢结构房屋,使用方可能会要求改变其结构使用用途,需要对原主要受力构件(梁、柱等)进行加固,通常的方法是增加构件截面尺寸,以达到承载力设计要求.由于原结构构件已经处于受力状态,若直接考虑原截面的初始变形、初始应力及支承条件的改变,采用一次分析的方法,则整个结构体系属于状态非线性结构,考虑初始条件、采用顺序加载的方法比较繁琐,且易出错.本文采用“分阶段分析,线性叠加”的方法,可以准确地求出各构件截面的内力,此方法概念清晰,操作简捷,对其它类似改造的钢结构房屋同样适用.     

门式刚架结构设计浅谈

介绍了单层轻型门式刚架结构的特点,并就整个结构体系的布置、单个构件的设计要点、设计中应注意的一些问题作了系统阐述,以完善门式刚架结构设计,促进钢结构的发展。     

轻型门式刚架山墙结构体系设计探讨

通过对门式刚架中山墙结构常用的刚架端墙体系与构架端墙体系的特性分析,认为刚架端墙体系的工程适用性更强。同时,对目前门式刚架轻型房屋钢结构标准图中的刚架端墙体系进行了探讨,结合理论分析与工程实践,改进了刚架端墙结构体系设计方法与节点构造,使其既满足承载要求,又便于施工和节约材料。     

大吨位吊车门式刚架轻钢结构的设计

简要介绍了门式刚架结构体系及应用范围 ;阐述了大吨位吊车门式刚架轻钢结构的设计方法。提出应主要考虑刚架跨度、柱距及柱高 ,刚架柱截面 ,基础设计等方面 ,强调了设计注意事项。     

变截面工形柱平面内稳定极限承载力研究

基于非线性板壳有限元结构分析方法,对门式刚架变截面工形柱平面内稳定极限承载力进行了大挠度弹塑性分析研究。在考虑壁板局部屈曲和构件整体屈曲相关作用的同时,对影响稳定承载力的几何参数包括腹板宽厚比、翼缘宽厚比、构件楔率和构件长细比等进行了系统的分析和研究,并与现行《门式刚架轻型房屋钢结构技术规程》进行了比较,获得的结论对工程设计具有参考价值。     

基于有限元分析的轻钢结构优化设计研究

以轻型钢结构中的门式刚架为研究对象,以门式刚架结构体系用钢量最少为目标函数,并设定合理的约束条件,借助有限元程序ANSYS进行优化设计,结果表明这种优化方法是可行的,可供工程实践参考。     

凯鲍汽车制造有限公司门式刚架工程结构设计优化

用钢量一直是门式刚架轻型房屋钢结构设计的重要衡量指标,本文主要从门式刚架的高度,跨度,柱距,主刚架型式,次结构,以及围护系统等方面介绍了减少门式刚架用钢量的一些方法。     

Reliability-based integrated design of steel portal frames with tapered members

Integrated structural designs, with consideration of system reliability for steel portal frames comprising tapered members, are studied in this paper. The reliability-based integrated design (RID) directly checks the structural system limit states and the corresponding system reliability, based on structural nonlinear analysis. The nonlinear integrated analysis model, the semi-analytical simulation method employed for system reliability assessment, the development processes of RID format and the design application of RID formula and curves are presented in this paper. Design examples and comparisons among three different design formats demonstrate that RID proposed in this paper is of certain and consistent system reliability levels, and provides a feasible way for structural engineers to improve the design quality and flexibility of steel frame structures.     

Finite element reliability and sensitivity analysis of structures using the multiplicative dimensional reduction method

Finite element reliability analysis (FERA) has been used to evaluate the reliability of structures. In FERA, approximate methods are commonly used to estimate the mean and variance of the structural response, while its probability distribution is primarily derived based on the Monte Carlo simulation (MCS) method. This paper advances FERA by combining it with the multiplicative dimensional reduction method (M-DRM). The proposed M-DRM allows fairly accurate estimation of the statistical moments, as well as the probability distribution of the structural response. The distribution of the response is obtained using fractional moments, which are calculated from the M-DRM, along with the maximum entropy principle. The variance of the response, based on global sensitivity measures, is obtained as a by-product of the analysis. The proposed approach is integrated with the OpenSees software and is illustrated through examples of nonlinear finite element analyses of reinforced concrete and steel frames. The paper shows that the proposed approach is an accurate and efficient alternative for FERA.     

钢框架柱平面内整体稳定验算改进建议Ⅱ:数例验证(1)

针对我国现行钢结构设计规范存在的框架柱平面内整体稳定验算的不足，提出了改进建议。利用单层和3层钢框架的有限元分析结果，对现行规范方法和本文建议方法在内力计算与框架柱平面内整体稳定验算和截面强度进行了详细比较，对本文建议方法的精度与可行性进行了评价。     

钢框架柱平面内整体稳定验算改进建议Ⅱ:数例验证(2)

针对我国现行钢结构设计规范存在的框架柱平面内整体稳定验算的不足，提出了改进建议。利用单层和3层钢框架的有限元分析结果，对现行规范方法和本文建议方法在内力计算与框架柱平面内整体稳定验算和截面强度进行了详细比较，对本文建议方法的精度与可行性进行了评价。     

平面钢框架结构极限承载的体系可靠度评价

为了将基于结构体系可靠度的设计理论运用到钢框架结构的设计中,必须对工程中钢框架结构的体系可靠度做出实际的评价。本文考虑影响钢框架结构体系可靠度的主要因素,并根据现有的统计资料,对钢框架结构的体系可靠度做出比较实际的评价,为实现基于整体可靠度的钢框架结构设计奠定了一定的理论基础。     

钢筋混凝土框架结构体系可靠度分析

结构体系可靠度是一个40年来尚没有得到很好解决的问题,即使对于理想弹塑性体系,经典的结构体系可靠度分析也往往会遭遇两个难以克服的困难:相关失效与组合爆炸。近年来,基于概率守恒原理的随机事件描述,提出了广义密度演化方程,从而将确定性系统和随机系统分析纳入到统一的理论框架之中。基于这一进展,结合结构非线性全过程分析的位移控制算法,本文推导了结构静力非线性发展过程的概率密度演化方程。采用纤维梁柱单元进行结构非线性分析,研究钢筋混凝土框架结构的体系可靠度,并与Monte Carlo法进行对比分析。研究结果证明了概率密度演化理论对结构体系可靠度分析的适用性。     

Reliability‐based optimum seismic design of RC frames by a metamodel and metaheuristics

The present study is devoted to reliability‐based optimum seismic design (RBOSD) of reinforced concrete (RC) moment frames within the context of performance‐based design. A chaotic enhanced colliding bodies optimization (CECBO) metaheuristic algorithm is proposed to achieve the optimization task. In the framework of CECBO, chaotic maps are employed to achieve randomness that results in better convergence rate in comparison with its standard version. For reliability assessment of structures during the optimization process, the Monte Carlo simulation method is employed. In order to reduce the prohibitive computational burden of the MCS in the optimization setting, a metamodel is proposed to accurately evaluate the required deterministic and probabilistic structural seismic nonlinear responses. Efficiency of the proposed methodology for implementation of RBOSD process for RC frames is illustrated by presenting two numerical examples.     

Special braced stairs versus typical braced frames. New architectural-structural-seismic approach to stair design

This paper presents a new approach to the project of steel buildings, mainly focused on the architectural, structural, and seismic design of stairs. The objective is to design a structural stair system capable of controlling seismic damage and contributing to the bracing system of the building. The article begins with a review of the seismic standard (ATC, FEMA, and EC8) on which the current design criteria for new buildings with stairs are based. The research is based on two spatial building models (A–B) with the same bracing elements but placed differently. Reference Model A follows classical design approaches. It means, stairs are considered nonstructural elements that do not influence the seismic behavior of the building. This structure corresponds to typical braced frames (IV-CBF and EBF) according to EC8. Model B includes a stair system designed to help control the effects of inter-story drifts and inertia forces. In this case, the same bracing elements of Model A were integrated into the stair structure of Model B. A comparative seismic behavior analysis of typically braced frames (A) versus specially braced stairs (B) is presented. The research was based on the static nonlinear (pushover) analysis and the capacity spectrum method (ATC-40) according to the seismic performance levels (FEMA) and damage limitation (EC8). Finally, the braced stairs was verified via nonlinear time-history analysis in order to better capture the structural safety of the evacuation routes and their influence on the behavior of the building. This deterministic analysis of the braced stairs verified satisfactory results compared to reference bracing systems.     

门式钢刚架结构实用抗火临界温度计算方法

本文应用Ansys程序,针对门式钢刚架结构,变化各种参数,进行了多个不同算例的结构整体抗火临界温度的计算。在对算例结果进行参数分析的基础上,忽略次要参数,考虑主要参数,得出了适用于跨度小于52m,高度小于10m,截面高度小于900mm的任意门式钢刚架结构整体抗火临界温度的简化计算表格,可方便地用于该类结构的抗火设计。