Second-Order Analysis of Multistory Building Frames by Marching Technique

A computer algorithm, expressed in the BASIC language, is described to make the second order analysis of multistory building frames by marching technique. Material property has to be linear elastic, and deformation due to axial force is ignored. Two second-order effects are considered; they are the reduction of column stiffness due to the presence of axial force, and the inclusion of the overturning moment arising from the product of the column load and the sidesway.
To minimize computer storage and running time, the marching technique is used wherein the global stiffness matrix is established one story at a time upon calling input data progressively downward beginning with the top story. Joint displacements of each story are expressed in terms of those of the story immediately below so that their values of the lowest story are obtained first. In this way, the largest inversion is of the size of the degree of freedom at any one story level. One file is used to store the intermediate information so that the joint displacements of each story, along with the moments at ends of all beams and columns in that story, may be computed progressively upward beginning with the lowest story.     

Bifurcation Analysis of Multistory Building Frames by Marching Technique

A computer program is presented to show the algorithm that is used to give the buckling load factor and the effective lengths of all columns in a multistory building frame when these columns are subjected to a set of primary axial forces. Since the buckling load factor is the lowest multiplier of the primary axial forces that makes the determinant of the global stiffness matrix equal to zero, it has to be found by trial and error. It is found that the determinant of the global stiffness matrix is the product of the pivots used in the piecewise small inversions within the earlier one on bifurcation analysis lies in the way by which the determinant is computed. Significant amount of computer time is saved because of the need of repetitive computations of the determinant at many trial values of the buckling load factor.     

Bifurcation Analysis of Multistory Building Frames

By assuming incompressible beams and columns in a multistory building frame, the frame may assume either a primary state equal to its underformed shape or a buckling mode when it is subjected to a set of primary axial forces that constitute the bifurcation loading. This article describes the theory and algorithm for a computer program by which the buckling load factor for a set of proportionate primary axial forces and the shape of the buckling mode may be obtained. It is shown that the buckling load factor thus obtained can be used to produce and effective length ratio for every column so that the Euler load of a pin-ended column with this effective length is identical to the actual buckling load of that column in the multistory building frame.     

提模施工纵向框架多层厂房体系

本文介绍一种用提模法施工的纵向框架多层厂房新体系。其特点是框架和墙板用提模法浇注混凝土,纵向边框主梁兼作外墙,可用轻型机具(25吨米塔吊)建造五层及五层以上的厂房。通过无锡市三个工程18,000平方米多层厂房的设计和施工实践,表明该体系施工速度快,综合技术经济指标好,可以满足一般轻工业多层厂房的使用要求。     

Elastic-Plastic Analysis of Rectangular Frames

For a ductile material such as steel, the stressstrain curve may be taken as linear up to the yield point and then indefinitely horizontal. Under this assumption, the first-named author has shown in 1963 that the response of a continuous beam or rigid frame under increasing loads may be traced from the beginning to collapse by a stepwise elastic analysis procedure. This procedure requires that the structure is subjected to concentrated loads only so that plastic hinges can form only at the ends of the elements which are themselves unloaded. In this paper, this restriction is removed by allowing uniform and concentrated loads to act on the elements. Consequently, a plastic hinge may form anywhere on an element, and the fixed-end moments and the stiffness coefficients of that element must then be modified for the next stage of elastic analysis. The advantage gained is enormous because previously a uniform load has to be replaced by a number of concentrated loads and a node placed at any point where there is a concentrated load.     

多层钢框架二阶弹性内力分析

采用有限元分析软件，分别对4个典型框架模型进行了一阶和二阶弹性内力分析，并通过与现行《钢结构设计规范》（GB50017-2003）给出的一种二阶弹性分析的近似方法的计算结果作对比，分析了该近似方法对于各种形式框架的适用性。     

多层组合结构建筑的整体平移旋转技术

建筑的整体平移旋转技术为未来的城市规划改造开辟了一个新途径。通过工程实例阐述多层组合结构 (框架结构和砌体结构组合 )建筑的整体平移旋转新技术。     

端板连接半刚性节点对多层钢框架设计的影响

我国目前将端板连接按刚性节点进行设计,主要用在单层门式刚架结构中,对多层钢框架由于缺乏计算理论和方法,与实际情况相差很大,特别是对抗震性能的影响很大.针对端板连接节点,采用有限元分析的方法,利用试验和有限元计算得到的节点刚度转角曲线,将半刚性端板连接节点视为弹簧单元,通过通用有限元软件Ansys建立有限元模型进行计算分析.对比了将端板连接视为刚性和半刚性两种情况下钢框架的内力和变形,在钢框架分析和设计中,应考虑半刚性节点的影响.并给出一些在设计时考虑节点刚度的建议,希望能够对实际工程设计有所助益.     

多层、高层建筑结构弹塑性动力、静力分析

应我国高层、超高层建筑发展需要,我们对建筑结构弹塑性动力反应分析软件进行了探索研究,在“高层建筑结构空间有限元分析与设计软件SATWE”的基础上,开发了一套简单实用的建筑结构弹塑性动力、静力分析软件EPDA。目前的EPDA软件提供了两种弹塑性分析方法,一种是弹塑性动力时程分析法,其力学模型有三种:层模型、平面模型和空间模型;另一种是弹塑性静力分析方法,就是通常所说的静力推覆分析方法。EPDA软件是我国第一套商品化的弹塑性分析软件,可以按任意给定方向计算结构的弹塑性时程响应,适用于各种材料的高层及超高层建筑结构,包括钢筋混凝土结构、钢结构和钢与混凝土混合结构,同时,程序中还考虑了多塔、转换层等结构特性。EPDA软件具有如下特点:(1)前后处理功能强,自动读取SATWE和Sat2000的设计分析结果,对钢筋混凝土构件,给出自动选筋结果,用户可以交互修改成实配钢筋;(2)采用纤维束模型模拟梁、柱、支撑等一维构件,纤维束模型的适用性好,不受截面形式和材料限     

采用纤维铰法的钢框架二阶非线性动力分析

考虑几何非线性和材料非线性,建立了适用于钢框架非线性动力分析的简洁且有效的数值程序。通过采用拉弯或压弯下梁柱节点稳定性求解中的稳定函数来考虑几何非线性。通过追踪横截面上整合点处沿杆长方向每个纤维的单轴应力-应变关系,确定横截面上沿杆长方向的的塑性发展。通过采用平均加速度方法的计算机程序,求解动力方程。与ABAQUS程序计算结果对比,验证了本程序的准确性和计算效率。     

汶川地震中广元市底层框架结构房屋震害调查与分析

2008年5月12日汶川里氏8.0级地震发生后,根据四川省广元市及其下辖青川县和苍溪县震害现场调查记录,比较归纳了三地21幢底层框架结构房屋的震害特征,分析了结构发生各种破坏的原因,对底框结构房屋抗震设计提出了建议.     

内框架房屋抗震的空间分析

内框架房屋的脉动振型、强拉变形曲线以及震害规律,进一步证实楼盖的有限刚度和高阶空间振型对震害程度和破坏部位的显著影响。以往采用的“单竖杆多质点系”计算简图未能反映这些特点。 本文提出考虑楼盖水平变形的空间结构模型,建立“多竖杆多质点系”的自振方程,应用反应谱理论求解多阶空间振型的地震反应,给出考虑楼盖空间作用及砖墙弹性和非弹性变形阶段的构件地震内力。通过实例分析说明,计算结果与实测自振特性和震害规律都有着较好的一致性。     

柔性节点钢框架的二阶弹塑性极限承载力研究

本文将有限元与Rayleigh-Ritz法相结合,建立了柔性节点钢框架的二阶弹塑性分析法。本文方法由于具有有限元与Rayleigh-Ritz法各自的优点,因而不仅有效地减少了所需求解的未知量,而且具有内存少、速度快和计算精度高等特点。对算例的分析研究表明,节点柔性将显著影响钢框架结构的稳定和极限承载力,而影响程度主要取决于梁线刚度与节点刚度系数之比EI/K_oι和柱中最大轴压比N/N_Y。经对大量算例结果的分析归纳,本文给出了考虑节点柔性的钢框架极限承载力实用计算方法,计算精度能满足工程需要。     

某双塔大底盘超限高层动力弹塑性分析

文章采用动力弹塑性时程分析方法评估某对称双塔大底盘超限高层结构在罕遇地震作用下的抗震性能和能力,了解其动力特性、屈服机制和破坏特征,并检验了关键薄弱部位的抗震安全性。计算结果显示该结构具有较强的抗震承载力,呈核心筒剪力墙连梁的＂梁铰破坏＂特征,达到了＂大震不倒＂的抗震设防目标。     

Approximate Analysis of a Floor Assembly in a Multistory Building Frame

A computer algorithm, along with a workable program in the BASIC language, is presented by which each floor beam in a multistory building frame, together with the attached columns, may be analyzed as a subassembly. The objective is to obtain results close to those which would otherwise be obtained by a whole frame analysis. With the subassembly analysis method, more trials may be made in the preliminary design stage, although whole frame analysis still needs to be employed when deemed appropriate.
The subassembly method may be in first order, or in second order including both column instability and Pdelta effects, allowing the same options as in whole frame analysis. The far ends of the upper columns are assumed to be connected to plates fixed against rotation but free to have sidesway. The connections themselves, however, may be semirigid, rigid, or overrigid, quantitively described by a set of rotation coefficients that may be preset or automatically generated. The far ends of the lower columns are similarly connected, defined by another set of rotation coefficients; but the plates are restrained in both rotation and sidesway. The floor beams have unknown slopes at the columns, as well as an unknown sidesway.
Rotation coefficients for various patterns of gravity loads are suggested in the article, and they are automatically generated for combined gravity and lateral loads. They may be taken, too, from any trial or similar whole frame analysis.     

关于多层厂房振动的几个问题

多层厂房的振动属微振问题,具有空间传递效应,分析中要考虑楼板的竖向振动和振动叠加的影响。可以由试验确定多层厂房的动力特性参数如阻尼比、动力弹性模量及波速。对多层厂房振动影响最大的频率谱主要集中在第一频谱密集区。振动的综合效应与开动的设备台数有关。为减小振动的影响,在震源布置、结构选型和构造方面均应采取相应的措施。     

节点刚度对多层钢框架静力性能的影响分析

由于缺乏计算理论和方法,大多数半刚性节点按刚性节点进行设计,与实际情况相差很大.介绍了实际工程中多层钢框架结构经常采用的半刚性连接形式;采用有限元分析的方法,将半刚性连接节点视为弹簧单元;通过通用有限元软件Ansys建立有限元模型进行计算分析,研究了节点刚度对多层钢框架结构变形和内力的影响.计算结果表明,采用了半刚性连接的钢框架结构,相对于理想刚接的情况,结构的内力和变形都有很大变化.在钢框架分析和设计中,应考虑半刚性节点的影响.     

多层与高层工业及民用建筑结构自振特性分析

本文按等效连续板分析方法对剪力墙、框架、框架－剪力墙结构分别给出了等效刚度、广义质量、自振频率与振型计算公式，这组公式简单、方便，易于计算，为建筑结构动力设计计算提出了一种可供探讨与发展的方法。文后给出了几个算例，并与有限元或实验结果进行比较，说明符合工程计算精度需要，比现有手算方法有很大程度的改善。     

论多层厂房结构设计

通过实例,介绍了多层厂房的结构设计过程,着重讲述了大跨度梁的结构形式选用、吊车荷载的输入、楼面活荷载的输入等内容,为同类工程的设计提供了详实的参考依据.     

Leveling of a Multistory Building Subject to Seismic Effects

A set of measures designed to protect and restore the operational suitability of a building in the suburb of Sochi is described.