A quadratic complementarity problem related to the optimal design of a pipeline freely resting on a rough sea bottom

A submarine pipeline resting on a rigid, frictionless seabed assumes an equilibrium configuration which can be determined by solving a unilateral contact problem, i.e. a quadratic program or a variational inequality.When the sea bed is irregular, its profile along the sealine can be modified, in present offshore technology, by means of costly trench excavations or artificial supports, in order to avoid excessive bending moments in the pipe. Thus, the problem arises of determining the minimum cost of the profile changes provided that a specified curvature is nowhere exceeded.This optimal design problem is solved by assuming a quadratic cost function and reducing it to a sequence of convex quadratic programming problems leading to the optimal design situation. Upper and lower bounds on the absolute minimum cost and optimality conditions are established. A suitable algorithm for solving the problem in a finite number of steps is developed. Its generalization to allow for ‘fixed charges’ due to the equipment mobilization cost is presented. Two numerical examples illustrate the optimum (minimum cost) proposed design method.     

灵江特大桥栈桥设计与计算

结合工程概况,从梁Ⅰ40a工字钢检算、Ⅰ16工字钢栈桥横向分配梁、Ⅰ28b支座垫梁验算、钢管桩自由长度及稳定性验算、栈桥钢管桩单桩承载力计算等方面介绍了栈桥的设计与计算过程,以供类似桥梁工程的设计参考。     

低洼小区雨水排水的探讨

随着城市建设的大规模开展,大型低洼小区排水成为经常遇到的难题。该文通过工程实例,分析如何利用挡水设施、地面径流控制措施、现场外径流控制措施等方法,解决大型低洼小区雨水排水问题,以期用最低的投资来获取最大的排水安全性。     

谈结合城市设计概念的现代博物馆建筑设计--以连云港市新博物馆方案设计为例

城市设计概念在过去的二十年里逐渐成为建筑设计所关注的新热点,也为建筑设计提供了新的出发点和方法途径.博物馆建筑作为公共建筑的一种类型,与城市关系密切,又具有建筑类型自身的特点.本文试图通过笔者参与设计的连云港市新博物馆方案为例,重点探讨建筑创作中的城市设计维度问题以及博物馆建筑设计的发展趋势.     

Numerical simulation of concrete encased steel composite columns

This paper investigates the behaviour of pin-ended axially loaded concrete encased steel composite columns. A nonlinear 3-D finite element model was developed to analyse the inelastic behaviour of steel, concrete, longitudinal and transverse reinforcement bars as well as the effect of concrete confinement of the concrete encased steel composite columns. The interface between the steel section and concrete, the longitudinal and transverse reinforcement bars, and the reinforcement bars and concrete were also considered that allowed the bond behaviour to be modeled and the different components to retain their profile during the deformation of the column. Furthermore, the initial overall (out-of-straightness) geometric imperfection was carefully incorporated in the model. The finite element model has been validated against published experimental results. The main objective of the study was to understand the structural response and modes of failure of the columns and to assess the composite column strengths against current design codes. The study covered slender, non-slender, stub and long concrete encased steel composite columns. The concrete strengths varied from normal to high strength (20-110 MPa). The steel section yield stresses also varied from normal to high strength (275-690 MPa). Furthermore, the variables that influence the composite column behaviour and strength comprising different slenderness ratios, concrete strength and steel yield stress were investigated in a parametric study. It is shown that the increase in structural steel strength has a small effect on the composite column strength for the columns having higher relative slenderness ratios due to the flexural buckling failure mode. The composite column strengths obtained from the finite element analysis were compared with the design strengths calculated using the American Institute for Steel Construction AISC and Eurocode 4 for composite columns. Generally, it is shown that the EC 4 accurately predicted the design strength for the concrete encased steel composite columns having a concrete cylinder strength of 30 MPa and structural steel yield stresses of 275 and 460 MPa, which are in the limits of the code, which otherwise, was generally conservative. The AISC predictions were quite conservative for all the concrete encased steel composite columns.     

对淮南煤电化企业规划设计中合理用地的探讨

介绍了企业规划建设力求紧凑合理的原则，从建设发展工业区、荒地次地的利用、发展循环经济等方面介绍了淮南煤电企业规划设计中合理用地的途径，提出应坚持依法利用土地的要求。     

低高度PPC简支梁桥工程实践

随着高强钢绞线、新型锚具等现代预应力技术的发展以及施工技术水平的提高，低高度PPC梁（注：即部分预应力混凝土梁）的应用日益广泛，它不仅能够降低构筑物的建筑高度、缩短构筑物的长度、减少占地拆迁面积和工程造价，而且在景观上也具有良好的效果。本文以实例介绍其设计构思。     

关注建筑表皮——托马斯.赫尔佐格与赫尔佐格&德梅隆的建筑表皮设计手法比较

建筑表皮是近年在建筑界关注的热点,而托马斯·赫 尔佐格以及赫尔佐格＆德梅隆是在这个方面很活跃的世界级建 筑师。文章试从建筑表皮设计的角度出发对他们的设计手法进 行比较分析。尽管他们设计的出发点,材料的运用,以及对建筑 艺术与技术侧重的不同,造就了他们设计手法的差异。但他们都 设计出了优秀的作品,实现了技术与艺术完美的结合。     

某已建工程中柱子加固设计的介绍

结合工程实例,介绍了采用加大截面法加固柱子的设计方法,可供同类建筑物加固设计时参考使用。     

勘察质量对基础工程的影响及对策

文中指出当前对勘察工作管理不重视，导致勘察市场混乱，并例举由于勘察质量的粗糙，导致延误工期、浪费及安全事故等，并提出解决问题的办法。