Towards the Design of Durable and High-Performance Tubular Structures

基础设施是加拿大生活各个方面的核心。基础设施过早恶化和修复损坏是数十亿美元的问题。拟议的研究计划的动机是越来越多的报告在服务性能差，甚至危险的崩溃镀锌钢结构在北美。将开发解决方案，以提高结构性能，延长由镀锌空心结构截面（HSS）构件和连接件组成的桥梁、高速公路和停车场结构、工业厂房和输电塔的使用寿命。长期目标是促进加拿大耐用和高性能基础设施的设计，制造，建造和维护。 该研究将首先解决热浸镀锌过程中HSS组件开裂的当代问题，然后对静态和疲劳载荷下镀锌HSS连接的行为进行一系列实验和数值研究。将研究冷成形、焊接、镀锌、应变时效、液态金属脆化和排气孔对接头性能的综合影响。将生成HSS制造规范和裂纹控制指南的补充规则，以：（1）帮助加拿大钢铁制造商、装配商和镀锌商优化其生产流程;以及（2）帮助加拿大工程师指定适当的应对措施水平，以最大限度地减少HSS部件在热浸镀锌期间发生裂纹的风险。该研究还将更好地了解镀锌HSS连接件的特性和结构性能。将制定坚固、经济有效和持久的管状结构的设计指南和建议。* 高性能钢结构在经济、环保、节能等方面具有明显的优势。然而，现行加拿大钢设计规范中针对传统钢的设计规则限制了工程师充分利用“新一代”极高强度冷成型高速钢的结构和建筑优势，其固有的残余应力水平较低。这项研究将为现有的设计规范提供补充规则，以促进新技术的应用。将通过实验室实验和计算机建模来验证设计准则和建议。

Infrastructure is central to every aspect of life in Canada. Premature deterioration of infrastructure and repair of damage are multi-billion dollar problems. The proposed research program is motivated by an increasing number of reports on poor in-service performance and even hazardous collapse of galvanized steel structures across North America. Solutions will be developed to improve the structural performance and extend the service life of bridges, highway and parking structures, industrial plants and transmission towers composed of galvanized Hollow Structural Section (HSS) members and connections. The long-term goal is to facilitate design, fabrication, construction and maintenance of durable and high-performance infrastructure in Canada.*** The research will first address the contemporary issue of cracking of HSS components during hot-dip galvanizing, followed by a series of experimental and numerical investigations on the behaviour of galvanized HSS connections under static and fatigue loadings. The combined effects of cold-forming, welding, galvanizing, strain ageing, liquid metal embrittlement and vent holes on the joint capacities will be investigated. Supplemental rules to HSS manufacturing specifications and crack control guidelines will be generated to: (1) help Canadian steel manufacturers, fabricators and galvanizers optimize their production processes; and (2) help Canadian engineers specify appropriate levels of counter-measures to minimize the risk of cracking in HSS components during hot-dip galvanizing. The research will also provide a better understanding of the characteristics and structural performance of galvanized HSS connections. Design guidelines and recommendations for robust, cost-effective and long-lasting tubular structures will be established.*** Structures composed of high-performance steel have obvious advantages in economical, environment protection and energy-saving aspects. However, the design rules in the current Canadian steel design specification, which are intended for conventional steel, are limiting engineers from fully utilizing the structural and architectural advantages of the “new-generation” very-high-strength cold-formed HSS with inherent low levels of residual stress. The research will generate supplemental rules to the existing design specification to facilitate the application of the new technology. Validation of design guidelines and recommendations will be achieved by laboratory experiments and computer modelling.