浅议混凝土裂缝的成因与预防及处理

针对混凝土裂缝现象,介绍了混凝土裂缝的危害,分别对干缩裂缝、塑性收缩裂缝、温度裂缝等常见裂缝产生的原因进行了分析并提出预防措施,阐述了各种裂缝处理办法,以期指导实践,减少甚至避免裂缝。     

带裂缝混凝土碳化深度预测模型

裂缝的存在大大的加深了碳化深度。为探索裂缝对混凝土碳化的影响,根据Fick第二定律和热传导方程的相似性,利用有限元软件建立了碳化仿真模型。开展了裂缝混凝土碳化试验,并根据试验数据调整了无裂缝、窄裂缝、宽裂缝有限元模型参数,进而对裂缝处混凝土碳化深度影响因素进行了模拟分析。结果表明,裂缝宽度比裂缝深度影响更大。提出了裂缝碳化深度增大系数,结合前人碳化深度模型,修正建立了带裂缝混凝土裂缝处碳化深度模型。     

建筑物裂缝的类型及诊治

建筑物中存在许许多多的裂缝,而裂缝又有着各种不同的成因和各式的形态,本文描述了裂缝的形态,分析了裂缝的成因,阐述了裂缝的危害、裂缝的观测和裂缝的处理.     

混凝土裂缝分析及控制措施

介绍了混凝土裂缝的类型,分析了塑性裂缝、温度裂缝、沉降裂缝、基岩约束裂缝的产生原因,主要从控制原材料与改善施工工艺两方面论述了裂缝的控制措施,为混凝土裂缝的防治积累了经验。     

房屋常见砌体裂缝的鉴别与处理

基于砌体裂缝的危害性,对沉降裂缝、温度变形裂缝和结构受力裂缝等进行了分析,介绍了裂缝的鉴别方法,提出了裂缝处理的基本步骤和原则,并给出了常见裂缝的处理方法,从而更好地解决砌体结构的裂缝问题。     

屋常见砌体裂缝的鉴别与处理

基于砌体裂缝的危害性,对沉降裂缝、温度变形裂缝和结构受力裂缝等进行了分析,介绍了裂缝的鉴别方法,提出了裂缝处理的基本步骤和原则,并给出了常见裂缝的处理方法,从而更好地解决砌体结构的裂缝问题.     

钢筋混凝土裂缝的控制和预防

介绍了混凝土塑性干缩裂缝、沉降裂缝、收缩裂缝、温度裂缝等施工中常见的裂缝,分析了裂缝产生的原因,针对性地提出裂缝的控制措施和预防办法,以期避免混凝土裂缝的产生,保证施工质量。     

混凝土施工过程中裂缝的控制

分析了混凝土裂缝产生的机理,针对不同类型的混凝土裂缝,如塑性裂缝、沉降裂缝、干燥裂缝、自身裂缝、碳化裂缝等,提出了具体的防控措施,并对原材料的选择方法作了介绍,以有效控制混凝土裂缝的产生。     

钢筋混凝土梁裂缝的分析与处理

根据混凝土结构设计规范中裂缝的成因和构件裂缝控制等级及最大裂缝宽度限值,经过系统的试验分析和整理,归纳了钢筋混凝土梁式结构常见裂缝问题,描绘了各类裂缝的典型特征及分析了各类裂缝原因,给出了裂缝治理的一般方法。     

沥青路面裂缝成因及修补技术研究

阐述了沥青路面裂缝修补的重要性;介绍了沥青路面裂缝的类型和裂缝形成机理,针对沥青路面裂缝,介绍了沥青裂缝修补养护工艺,并提出了沥青路面裂缝预防性措施。     

桥台搭板结构型式设计的探讨

介绍了设置搭板是正常路段向桥台过渡连接的最好办法 ,并指出搭板设计是否合理直接影响到整个路桥过渡段的使用性能。就结构组合设计的原则和搭板设计方法作了详细说明     

Microcomputer-Aided Instruction of Structural Steel Design

An innovative approach is reported for teaching structural steel design in a civil engineering undergraduate curriculum. It is based on the interactive environment and graphic capabilities of inexpensive microcomputers. Ten BASIC interactive microcomputer-aided design programs have been developed and used in a senior-level structural steel design course at the Ohio State University. The approach of interactive design and the interactive microcomputer-aided design programs make the learning of structural steel design more exciting and result in more effective training of future designers. Students can gain experience and develop insight in structural design while they are still in an academic environment.     

基于线结构思维的建筑设计手法探析

本文通过对线与建筑表达的线结构思维的分析,对基于线结构思维的建筑设计方法进行了研究,提出了“运用结构的设计手法、运用结构与建筑外立面多元共生的设计手法及运用建筑形态构成的设计手法”等基于线结构思维的建筑设计手法.     

Integrating Structures and Design in the First-Year Studio

Introducing structures learning to the first-year architectural design studio situates structures as fundamental to both the design process and architectural expression. At the Illinois Institute of Technology, we use dynamic modeling techniques and large-scale installations to help students develop a visual and tacit structural intelligence, and to encourage students to take a greater interest in structural systems as a design concern. Similar to a design-build teaching model, our approach relies upon active experimentation with structural models and installations, and reveals the latent design potential in structural systems.     

A value-based design approach for base-isolated structural systems

The main assumption in seismic design procedures for structural systems is to provide the building with a high level of structural performance, subjected to earthquake loads. Such demand for higher performance needs additional investment on the project. In this work by taking into account the socio-economical aspects of the project, a value-based design approach is used to rationalise the structural design procedure in terms of initial investment. Determination of value design point in this approach is based on providing the optimality criterion from a global perspective. According to the results of this study, while for hospitals located in small cities with no substitute functionality in case of earthquake incident using base isolation for the structural system is quite necessary, for large cities, construction of fixed-base hospitals can still be permitted. The study also shows that, in the countries with higher growth rate, the required structural capacity to deal with earthquake demands in value-based design approach is lower than that required for low growth rate regions.     

Consequence-based structural design approach for black swan events

The metaphor of black swan refers to unpredictable events like 9/11, the Indian Ocean tsunami, or the Oklahoma City Federal Building bombing, that cause catastrophic consequences for structural system safety. The likelihood of occurrence for such unforeseen events cannot be estimated from the observed data or prognosticated by experts. The absence of event and likelihood information renders futile the application of usual risk-based methods for design. Therefore, a shift from the probabilistic approach to consequence-based structural design is necessary for coping with the unexpected demands. This is accomplished through the conceptual development of a system capacity oriented design approach, where structural members are designed for variable reliabilities based upon their contribution to causing adverse system consequences. Information about general structural integrity encoded in the stiffness matrix is applied, using member consequence factors ranging from 0 to 1, for determining a member’s contribution towards system response. The structural system is designed using member consequence factors as additional partial factors on the resistance side of the design equations. The consequence-based scheme does not need a triggering hazard event (or its likelihood) and is an apt structural design approach for black swan events.     

On the design of Web-tapered,unequal-flanged structural steel columns

A study directed towards the development of an efficient and economical design for stability of structural steel members is described. A finite element method is presented for determining the lateral-torsional buckling load for linearly tapered I-section members with unequal flange areas. Solutions are obtained for different flange-area ratios and tapering ratios. Such solutions are used to develop an interaction relationship for tapered unequal-flanged steel structural colums subjected to both axial and bending stresses.The formulation is intended to provide a more rational approach to the design of tapered steel columns—a step towards an optimum stability design for structural steel members.     

The cost of satisfying design requirements on progressive collapse resistance – Investigation based on structural optimisation

This work is concerned with the explicit treatment of progressive collapse resistance within the structural design process. Progressive collapse resistance is associated with the damage tolerance of a structural system and controls the ability of the system to sustain local damage by absorbing the potential of triggering system collapse and suffering disproportionally large consequences. This work focuses on the design of elastoplastic steel frames. The measure of progressive collapse resistance employed is expressed as a ratio comparing the limit loads obtained with elastoplastic analyses of the intact structure and of an artificially damaged structure (‘damage’ is caused by the notional removal of a column from the intact structure). This measure is used to incorporate a constraint on progressive collapse resistance into a structural design optimisation formulation, which – in its classical form – takes only standard design code constraints into account and aims at minimising the structural cost. The developed optimisation approach is capable of producing cost-effective structural designs with acceptable system damage tolerance. By enforcing the satisfaction of the additional design requirement on progressive collapse resistance, structural cost is inevitably increased due to the need for extra material. This increase is quantitatively explored with the presented structural design optimisation approach.     

On the reliability-based design of structures including passive energy dissipation systems

This contribution presents a methodology for stochastic design of structures including vibration protection systems. The approach is then used to investigate the effect of uncertain model parameters on the reliability-based optimal design of structures with a class of passive energy dissipation systems. The uncertainty of structural parameters as well as the variability of future excitations are characterized in a probabilistic manner. The optimal design problem is formulated as a non-linear constrained minimization problem involving multiple design requirements, including reliability constraints related to the structural performance. Failure events defined by a large number of random variables are used to characterize the reliability measures. A sequential optimization approach based on global conservative, convex and separable approximations is implemented for solving the optimization problem. The effects of uncertain model parameters on the performance, robustness and reliability of protected systems is illustrated by two example problems that consider multi-story buildings under stochastic ground excitation.     

新尤文图斯体育场结构设计

为了1990年世界杯而兴建的意大利都灵阿尔卑斯体育场,在建成约19年后被一座称为新尤文图斯的新体育场所代替。新体育场的设计以最新的体育场及体育设施的设计规范为依据。本文介绍了该新体育场建筑设计和结构设计所采用的方法。主要阐述了基础系统、大型看台的框架体系、悬挂屋顶结构体系、边界风洞实验室的试验测试工作以及施工安装等。