Innovative analysis and design of steel structures for lateral torsional buckling

结构钢作为建筑材料具有以下几个优点：施工速度快，强度重量比高，连接简单，结构修改方便，以及能够桥接相对较长的跨度。因此，结构钢在加拿大广泛用于各种应用，包括工业结构，炼油厂，发电厂，石化厂，管架，高层建筑，商业结构，体育场和竞技场。在这样的应用中，大跨度横向无支撑梁被认为是由其横向扭转屈曲失效模式。考虑到侧扭屈曲理论的复杂性，目前的设计标准仅为基本设计情况提供了简单的解决方案。将这种简化的设计程序应用于实际的复杂问题会导致（a）过于保守的设计，从而导致结构的成本高于所需的成本，或者（B）不一致的安全裕度。在此背景下，拟议的研究计划的目的是推进横向扭转屈曲的钢构件的分析和设计方法。* 拟议的研究将检查加拿大现行设计标准中未考虑的对钢构件横向扭转屈曲强度的各种影响，包括：（a）构件初始不直度，（B）屈曲前变形，（c）横截面变形，以及（d）玻璃纤维增强聚合物（GFRP）等现代加固材料板的存在。这项研究还将通过发展解释多重效应的一般化理论来研究这些效应的相互作用。将开发一系列分析和设计方法;从简化/保守到复杂/准确。这些方法将涉及（a）制定和实施可靠的先进梁屈曲理论和有限元，（B）基于壳体和三维有限元分析模型开发三维有限元分析模型，用于评估和验证，（c）开发针对常见设计问题的分析结果的综合数据库，以及（d）制定适用于设计的简化方程。* 该研究计划预计将为结构工程师提供一个基础，以在结构安全和经济性之间取得明智的平衡。从长远来看，采用来自拟议研究的先进分析/设计方法有望为加拿大钢结构设计带来显著的经济效益。

Structural steel offers several advantages as a construction material: speed of construction, high strength-to-weight ratio, connection simplicity, amenability to structural modifications, and ability to bridge relatively long spans. As such, structural steel is widely used in Canada in various applications including industrial structures, oil refineries, power plants, petrochemical plants, pipe racks, high rise buildings, commercial structures, stadiums and arenas. In such applications, long span laterally unsupported beams are known to be governed by their lateral torsional buckling mode of failure. Given the complexity of lateral torsional buckling theory, current design standards provide simple solutions only for basic design situations. The application of such simplified design procedures to realistic complex problems lead either to (a) overly conservative designs resulting in costlier structures than needed or (b) inconsistent margins of safety. Within this context, the proposed research program aims at advancing methods of analysis and design of steel members for lateral torsional buckling. ***The proposed research will examine various effects not considered in present Canadian design standards on the lateral torsional buckling strength of steel members, including; (a) member initial out-of-straightness, (b) pre-buckling deformation, (c) cross-sectional distortion, and (d) presence of plates of modern strengthening materials such as Glass Fiber Reinforced Polymer (GFRP). The study will also examine the interaction of such effects by developing generalized theories which account for multiple effects.***A spectrum of analysis and design methodologies will be developed; ranging from the simplified /conservative to the sophisticated/accurate. Such methods will involve (a) formulating and implementing reliable advanced beam buckling theories and finite elements, (b) Developing 3D FEA models based on shell and 3D FEA models for assessment and validation, (c) developing a comprehensive database of analysis results for common design problems, and (d) formulating simplified equations suitable for design. ***The research program is expected to provide structural engineers a basis to strike an informed balance between structural safety and economy. Over the long term, the adoption of advanced analysis/design methods stemming from the proposed research are expected to realize significant economic benefits to the design of steel structures in Canada.**