Effect of inplane edge constraints on natural frequencies of simply supported doubly curved shallow shells

Reasonably accurate natural frequencies are presented for simply supported shallow shells on rectangular planform subjected to 55 possible combinations of edge constraints. Thin shallow shell theory is used. Accurate natural frequencies of doubly curved shallow shells are presented and can be used for benchmarking by researchers as well as reference data for practicing engineers. Natural frequencies are presented for various shell curvatures including spherical, cylindrical and hyperbolic paraboloidal shells.     

Normalized Relationships for Depth of Embedment of Sheet Pile Walls and Soldier Pile Walls in Cohesionless Soils

Normalized, non-dimensional relationships for calculating the depths of embedment of sheet pile walls and soldier pile walls embedded in cohesionless soils are presented. Rankine theory for lateral earth pressures in active and passive conditions are used in the analyses. Relationships are presented for cantilever walls and walls propped at crest. The proposed relationships can be used in dry soil conditions and as well as in saturated soil conditions with steady state seepage. The embedment depth relationships are presented in terms of non-dimensional parameters and can be used for a variety of soil conditions, dimensions and spacing of the walls, and depths of excavation. The presented relationships are simple, easy to use, and do not require tedious calculations.     

埃航B747飞机维修机库钢结构设计

埃航B747飞机维修库跨度81.5m,采用钢网架、格构式钢柱的全钢结构,是目前非洲跨度较大的飞机维修机库之一。介绍了飞机维修机库设计过程及其结构体系布置特点,重点对维修机库结构体系的布置、上下部整体分析进行了较详细的阐述,并对机库结构的动力模态响应和地震反应作了简要的介绍。     

Finite element analysis of plates on elastic foundations: an automated approach

An automated approach for the analysis of plates on an elastic foundation is presented. The approach combines automatic mesh generation with nonlinear analysis to analyse plates of arbitrary shape on an elastic foundation subject to uplift. Two separate complete systems are presented, the first employing an ACM element to analyse rectangularly-shaped plates and the second employing a heterosis element to analyse plates of arbitrary shape. Solutions of the systems are presented and compared to theoretical results. A convergence study is also presented.     

Automation of Knowledge Organization and Acquisition

In this paper, an ongoing investigation on the development of SPERIL Systems, which are knowledge-based expert systems for damage assessment of existing structures, is described. The development of a new version, SPERIL-3, is presented and the motivations for the development of this system are discussed. Specifically, knowledge organization and knowledge acquisition in this system are emphasized. The automation of knowledge acquisition is presented and discussed.
In this paper, an ongoing investigation on the development of SPERIL systems, which are knowledge-based expert systems for damage assessment of existing structures, is described. The development of a new version, SPERIL-3, is presented and the motivations for the development of this system are discussed. Specifically, knowledge organization and knowledge acquisition in this system are emphasized. The automation of knowledge acquisition is presented and discussed.     

一种新型混凝土异形柱--型钢混凝土异形柱的概念体系初探

针对型钢混凝土异形柱体系特点,对相关问题进行了评述,分析其特点及具有的优越性和应用前景,并提出了若干需要研究解决的问题.     

Design of prestressed stayed columns

General design procedures for prestressed stayed columns with a single cross-arm system are presented. The accuracy of the proposed design expressions is confirmed by comparison with the results of physical experiments and validated finite element simulations. Reliability is assessed by following the approach set out in Annex D of EN 1990. The presented resistance expressions for prestressed stayed columns are a function of the system geometry, the level of initial prestress in the cables and the global imperfection level. Worked examples are also presented to illustrate the application of the developed design approach.     

The influence of elasticity of joints on the behaviour of thin-walled structures

Application of modified technical torsion-flexural theory for analysis of slender thin-walled structures with elastic joints is treated in present paper. Theoretical approach and numerical assessments of the influence of elastic joints on the load-bearing capacity of thin-walled systems are presented. Theoretical approach under consideration of linear and non-linear influences possibly appearing is established. The numerical verifications of the problem specified are presented. Discussion and evaluation of the results and conclusions obtained are submitted.     

政府投资工程建设管理模式研究

本文分析了我国现行政府投资工程管理模式的基本特征和存在的弊端,借鉴西方发达国家和地区的先进经验,结合我国国情,提出了政府投资工程建设的“双层代理制”管理模式,分析了该建设管理模式的运作方式,提出了实施该建设管理模式的配套改革措施。     

状态方程转换矩阵的本征值计算

对工程结构动力分析中的转换矩阵的本征值问题进行了分析,提出了一种新的方法,从二次特征值的表达式出发求解了本征值的表达式,算例分析表明该方法具有计算效率高,精度好的优点。     

Study of lateral compression of round metallic tubes

A detailed experimental and computational investigation of round metallic tubes subjected to quasi-static loading is presented. Experiments were conducted wherein round aluminium and mild steel tubes of different diameter to thickness ratios were subjected to lateral compression in an Instron machine. Their deformation histories and load–compression curves were obtained. The deformation of the tubes has also been studied and analysed with the help of the finite element code FORGE2. Contours of nodal velocity, equivalent strain rate and equivalent strain at different stages of compression are presented and discussed. Experimental and computed results are compared. Basic mechanism of their deformation and the effects of process parameters on deformation behaviour of the tubes are presented and discussed.     

基坑支护结构土压力与抗力研究

探讨了基坑支护结构上主被动土压力的确定方法,通过具体的工程实例,比较了我国相关设计规程对m值取值的差异,并归纳了m法用于基坑支护计算的局限性,为基坑支护的设计提供了借鉴。     

预应力高强混凝土管桩基础若干实践问题

考察了广东地区预应力高混凝土管桩 (PHC桩 )在工程实践中存在的问题 ,对不同的地质状况下制定打桩收锤标准、桩约束设计、承载力计算、估算桩长等争议问题进行了论证 ,提出了修正技术方案     

高层住宅墙体的合理等效惯性矩

目前,一般高层住宅钢筋混凝土结构侧移刚度过大,导致地震作用过大.本文根据水平侧移的限值导出了合理的墙体等效刚度计算公式,并给出若干常用的墙段的等效惯性矩值,可供上机计算前的方案阶段参考.     

利用空气制冷的地下冷库

简要地概述了目前国内外冷库制冷技术的发展情况，并详细地阐述了带蓄冷器的不完全空气冷却制冷冷藏系统的工作原理、制冷设备、系统特点、存在问题以及解决问题的措施，说明了这种冷藏系统的优越性。     

锈蚀钢筋混凝土保护层破坏模式

本文采用弹性力学及有限元方法，分析钢筋锈蚀产物体积膨胀在周围混凝土中的应力分布。提出了混凝土保护层四种破坏模式：直角破坏、楔形破坏、垂直方向顺筋开裂及整层破坏。工程调查结果与本文提出的四种破坏模式吻合较好。     

Bending of Rectangular Plates with Variable Rigidities

A microcomputer-oriented semianalytical method of solution is presented for rectangular plates with variable rigidity or thickness. The solution procedure is based on the classical method of separation of variables. The two-dimensional governing partial differential equation is first reduced to and ordinary difference equation. The classical unidirectional finite-difference method is then employed to solve the resulting ordinary differential equation. Results are presented for plates with different edge and loading conditions. Results for partially loaded plates with variable rigidity or thickness are presented in the literature for the first time.     

生土围护墙倾覆倒塌高厚比限值分析

传统木构架土坯墙(土筑墙)房屋,在地震过程中,墙体会发生平面外的倾覆倒塌破坏。对墙体倾覆倒塌的过程进行了分析,通过建立墙体平面外倾覆倒塌简化分析模型,得到了使墙体倾覆倒塌的最小加速度公式,给出了影响墙体倾覆倒塌的各个因素和最小加速度的关系曲线,初步得到了在不同地震烈度下避免墙体平面外倾覆的高厚比限值,并就如何避免墙体在地震中发生倾覆倒塌进行了探讨。     

Theoretical investigation of the strength and stability of special pseudospherical shells under external pressure

The paper is devoted to a new shape of a shell of revolution with negative Gaussian curvature. The main part of the meridian of the shell is a plane curve of the Huygens tractrix. Geometrical properties of the middle surface of the shell of revolution are presented. The membrane state of stress for a family of shells with constant capacity and constant mass under uniform external pressure is analysed. The critical pressure, buckling modes and equilibrium paths for the family of shells are calculated with the use of the FEM (the ANSYS system). Results of the analytical and numerical investigations are presented in tables and figures. A stable post-critical behaviour of presented shells is pointed out which is not typical for most shell structures.     

黄浦体育中心办公楼斜柱结构计算分析

介绍某高层办公楼竖向设斜柱的结构采用SATWE和ETABS两种软件计算分析情况，重点是斜柱部分的内力分析和重要部位的中震下弹性分析，并介绍了相关节点的设计和构造加强措施。