Prediction of shallow-foundation settlements and selection of bed models for slab analysis

A brief review is given for the development of methods of analyzing slabs on an elastic bed (from N. M. Gersevanov to the present) with the isolation of problems relative to bed models. A method of settlement calculation is described on the basis of layer-by-layer summation with consideration of the structural strength of the soil and the slab suitable for use in the analysis.     

刚性路面板模型试验研究

针对工程中水泥混凝土路面板足尺试验难度较大的问题 ,提出采用相似理论进行刚性路面板的荷载和应力的试验研究方法 ,探讨混凝土路面板研究中相关基础理论问题。通过对 9块不同相似比的刚性路面板的试验研究 ,得到了几何尺寸相似的弹性地基板在静载作用下 ,力学性能相似的初步结论。     

弹性地基上矩形水池的计算及用表

本文对Winkler弹性地基上的矩形水池底板,用量纲分析和有限元计算的方法,提出了弯矩、刚度、传递系数和板边反力的计算用表,并提出了将其用于空间整体弯矩分配法进行弹性地基上矩形水池内力计算的实用方法。     

楼面裂缝的产生原因和预防措施

楼面裂缝历来是建筑工程中普遍存在的问题，产生裂的原因是多方面的，主要有：地其受力不均匀导致基础不均匀沉降，板预应力控制预制不准，安装预制板坐浆不均及灌缝不好，预埋管件的影响，板面层抹灰不当，混凝土的材料问题等，通过对这些产生楼面裂缝原因的分析，归纳出要有效地防止楼面裂缝的产生及发展，必须从设计，构件的预制，原材料的采购和使用方面加以防治。     

钢筋混凝土板的非线性有限元分析

利用板的屈服线理论，采用有限元分析方法，把钢筋混凝土板简化成以增量形式表达的弹性正交各向异性板，建立起板非线性有限元分析的数学模型和计算公式，给出材料的力学表达式和板的弯矩-曲率关系。     

底部大空间上部弱楼板高层结构动力分析子结构法

根据底部大空间、上部弱楼板高层结构的三维空间弹性分析结果 ,提出用子结构法对此类复杂体型高层结构进行整体分析。此法的分析结果与三维空间精细分析方法的结果比较接近 ,为分析复杂高层建筑结构的整体性能提供了一种有效的途径     

Accuracy of B. N. Zhemochkin's solution for circular slabs on an elastic half-space

Conclusions 1. For absolutely rigid slabs, the solution according to schemes A and B yields an approximation to the exact solution, from above and from below, for all the loadings here considered. Thus it is possible to obtain an upper and a lower evaluation of B. N. Zhemochkin's solution, for any number of unknowns. The solution according to scheme A converges somewhat more rapidly.2. For n=22, the greatest error in the values of the moments in a slab under a uniformly distributed load amounts to 8%. If the number of sections or the rigidity of the slab is increased, the error diminishes.3. For flexible slabs, the solution according to schemes A and B may not yield an approximation from both sides; the determining factors in this case are the flexibility parameters of the slab and the nature of the loading.It must be pointed out that a soil bed is not a linearly-deformable body. Even with small loads, plastic deformations take place in the soil under the edges of beams and slabs; they result in a considerable decrease of the maximum values of the reactions at the edges, and in a modification of the entire diagram of the reactions. For this reason, in many cases involving soil beds, the results of an analysis carried out by using a small number of unknowns show a better agreement with the experimental data than the results obtained by using a greater number of unknowns.Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 1, pp. 5–7, January–February, 1970.     

高层建筑结构分析中对楼板的模型简化

在复杂高层建筑结构分析中,对楼板的模型简化至关重要.本文从工程实用角度出发,对楼板给出了多种简化假定,并在高层建筑结构空间有限元分析与设计软件SATWE中实现了这些假定.在使用中可根据工程实际需要,灵活应用.SATWE软件还具有弹性楼板单元自动划分.自动生成各节点主从隶属关系等功能,从而可大大提高复杂高层建筑结构的分析精度和分析效率.     

弹性楼盖高层框-剪结构地震内力实用计算法

装配式楼盖的水平刚度是有限的,这已为房屋的脉动振型,楼盖实测变形以及房屋的震害现象所证实。本文提出考虑楼盖变形的空间结构力学模型,采取“栅格多质点系”计算简图,对160例8～30层高层建筑进行了地震反应分析,并以刚性楼盖假定的框架地震内力为基数,给出弹性楼盖框-剪结构各种情况下的中央框架地震内力修正系数。从而使目前通用的较简单的适用于框架-剪力墙并联体的“单竖杆多质点系”抗震分析方法,作一简单修正后,即能反映楼盖变形对框架地震内力的影响。     

Shrinkage stress analysis of concrete slabs in a multi‐storey building considering internal and external restraints

Shrinkage strains of concrete slabs in a multi‐storey building are restrained internally by reinforcement bars as well as externally by supporting members such as columns or walls. These strains may induce tensile stresses in concrete members and lead to cracks due to excessive shrinkage stress. In this study, a practical shrinkage stress analysis method for application to concrete slabs in a multi‐storey building is proposed. The proposed approach considers both internal restraint of reinforcement bars and external restraint variations resulting from construction sequence. The shrinkage stress due to external restraint is obtained by multiplying the relaxation coefficient by the elastic shrinkage stress. The additional shrinkage stress due to internal restraint is obtained by the residual strain calculated via a linear elastic analysis for external restraints. A verification example was comparatively analysed using the proposed method and a commercially available analysis program that is capable of time‐dependent analysis of concrete. The results of a 10‐storey sample building suggest that the internal restraint due to reinforcement considerably increases the shrinkage stress at slabs under loose external restraint. Copyright © 2008 John Wiley & Son, Ltd.     

基于塑性分析的钢筋混凝土箱梁悬臂板横向受力有效分布宽度

目前国内外相关设计规范中关于行车道板横向受力有效分布宽度的取值是基于弹性理论分析结果确定的,不能体现塑性阶段行车道板横向受力特点。通过对2个钢筋混凝土箱梁模型上的4块悬臂板进行荷载试验,得出悬臂板极限荷载和塑性铰线分布形式,并运用塑性分析方法,推导钢筋混凝土箱梁悬臂板在局部荷载作用下塑性有效分布宽度的计算公式。试验结果和理论分析比较表明:悬臂板的塑性有效分布宽度与荷载作用位置及单位板宽正、负极限弯矩值相关;满足构造配筋要求的箱梁悬臂板进行极限状态设计时,建议采用简化的三折线破坏模式进行塑性横向有效分布宽度计算,取正铰线扩散角为45°,负铰线扩散角为60°;荷载作用于悬臂板边缘时基于塑性的横向有效分布宽度是基于弹性分析的1.58倍。     

钢筋混凝土双向板的弯矩调幅方法

参照单向连续板的弯矩调幅方法 ,提出了双向板进行弯矩调幅的原则与方法 ,给出了供进行弯矩调幅用的计算表格 ,并且通过一个设计实例 ,介绍了双向板肋梁楼盖的弯矩调幅步骤与计算结果 ,还将此计算结果与按弹性分析方法和按极限平衡方法计算的结果作了对比     

Effect of local elastic wall deformations on the interaction between floor slabs and flanged shear walls

A finite-element analysis is made of the interaction between laterally loaded flanged shear walls and floor slabs in cross-wall structures. Particular attention is paid to the influence of local elastic wall deformations on the effective width and coupling stiffness of the slab, and on the critical bending moments in the slab. Design curves are presented to allow a rapid assessment to be made of these quantities for preliminary design purposes. The work is an extension of an earlier study of coupled plane walls.     

Elastic analysis of slabs

Most building codes permit the use of elastic design methods for concrete slabs. These methods for small deflection theory of slabs are discussed, and then graphically complete distribution of principal bending moment contours and trajectories, and deflections are obtained for simply-supported and encastre slabs subject to uniformly distributed load. Destructive tests on simply supported slabs designed elastically, according to code requirements, and by the yield line method are then described.     

基于混凝土不均匀性面板堆石坝面板损伤分析

将混凝土面板堆石坝中面板混凝土视为宏观上均质、细观上不均匀的材料,结合统计学原理,考虑材料参数分布的随机性,通过二维有限元数值分析,研究了混凝土的弹性模量和抗拉强度随机性对面板堆石坝面板动力损伤分布规律的影响。计算结果表明:不考虑面板混凝土材料参数随机性时,(0.65~0.85)H(H为坝高)处面板顺坡向应力较大,拉损伤主要发生在0.8H(H为坝高)附近的面板处;随着混凝土材料不均匀性增大,发生拉损伤的部位趋于分散,但主要集中在(0.4~0.9)H范围内的面板。因此这部分面板应该是抗震设计的重点区域。采用混凝土弹脆性细观损伤模型,考虑材料参数的随机性,能够直观地阐明混凝土面板的地震破坏过程和损伤分布,便于了解面板薄弱环节,研究成果可以为混凝土面板堆石坝抗震设计提供参考。     

压型钢板—混凝土组合楼板挠曲变形计算理论研究

本文从弹性理论出发,对压型钢板—混凝土组合楼板在各种连接条件下的变形计算,进行了较全面的研究,提出了考虑组合板界面相对滑移的挠曲变形理论计算方法。     

压型钢板-竹胶板组合楼板的力学性能试验研究

为拓宽竹材的应用范围,实现建筑结构构件材料和形式的多样化,本文在阐述竹材的构造和力学性能以及竹材改性产品的基础上提出了一种新型的组合楼板──将竹胶板与压型钢板用结构胶粘结成为压型钢板-竹胶板组合楼板,并针对这一新型组合楼板进行了试验研究及理论分析。以竹胶板厚度、芯部压型钢板厚度及组合楼板跨度为参数进行了6块组合楼板的力学性能试验。结果表明,压型钢板-竹胶板组合楼板的整体工作性能优良,竹胶板与钢板之间具有很好的组合效应,能够提供较高的承载力和刚度,其力学性能可以满足作为建筑楼板的需要。根据组合楼板在正常使用阶段的变形范围内呈现出理想弹性性能的试验结果,提出了组合楼板抗弯刚度的计算方法;根据破坏阶段的应力状态提出了组合楼板极限受弯承载力计算方法,据此计算的组合楼板跨中挠度及受弯承载力的计算值与试验值吻合较好。     

预应力混凝土边梁协调扭转的分析

通过对协调扭转的各种典型设计方法的适用性进行比较,指出对于不同的结构,必须合理选用相应的协调扭转分析方法。对承受较大协调扭矩作用的预应力混凝土边梁,协调扭矩的计算可根据不同阶段的受力特点采用其相应的变刚度。同时对次梁、板与边主梁截面形心相对位置的影响进行探讨,指出预压力对边梁抗扭承载力的影响。结合工程实例的有限元分析,说明此类结构的设计要点。     

火灾作用下混凝土双向简支板的挠度计算

小挠度薄板理论可以用来确定混凝土双向板正常使用时的挠度,当用于计算火灾作用下处于大挠度的双向混凝土板挠度时则会带来很大误差。在引入弹性板的大挠度微分控制方程后,考虑外加荷载与高温的共同作用,并计及高温下材料特性的变化,对火灾作用下钢筋混凝土双向简支板的挠度随温度的变化进行了分析。引入无量纲量,对大挠度微分控制方程进行无量纲化处理,并以无量纲板均布荷载为摄动参数,结合Galerkin方法提出了钢筋混凝土双向简支板火灾作用下挠度的计算式,计算结果与试验结果吻合较好,可为火灾作用下板的大挠度分析提供依据。研究结果表明：火灾作用下混凝土板的挠度与外加荷载和热弯矩均有关,与热弯矩成线性关系,而与外荷载则成非线性关系;当没有热弯矩时,挠度主要由外加荷载确定;当外加荷载恒定时,挠度则主要由热弯矩引起。     

Resistance to longitudinal shear of composite slabs with longitudinal reinforcement

Tests are reported on composite slabs with trapezoidal sheeting and longitudinal reinforcing bars above the troughs. The contribution from this reinforcement to resistance to longitudinal shear is found to be substantial. Analyses of the results lead to a design method that allows for it. It may not be possible to take full advantage in the design of this extra resistance, because the predicted deflection in service may then become excessive.An appendix gives an elastic–plastic model that accurately predicts the deflection of the slabs just before failure. A list of the principal nomenclature is included.