Development of inelastic design procedures for stainless steel indeterminate structures

不锈钢不确定结构非弹性设计程序的开发

• 批准号: EP/P006787/1
• 负责人: Marios Theofanous
• 金额: $ 12.87万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2017
• 资助国家: 英国
• 起止时间: 2017 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP006787%2F1
• 关键词: Development; inelastic; design; procedures; stainless

The excellent atmospheric corrosion resistance and favourable mechanical properties of stainless steel make it well suited for a range of structural applications, particularly in aggressive environments or where durability and low maintenance costs are crucial design criteria. The main disadvantage hindering the more widespread usage of stainless steel in construction is its high material cost and price volatility. However, life-cycle costing and sustainability considerations make stainless steels more attractive when cost is considered over the full life of the project, due to the high potential to recycle or reuse the material at the end of life of the project.The design of stainless steel structures is covered by a number of international design codes, which have either recently been introduced or or were recently amended in light of recent experimental tests, thus indicating the worldwide interest stainless steel has received in recent years. Despite the absence of a well-defined yield stress, all current design standards for stainless steel adopt an equivalent yield stress and assume bilinear (elastic, perfectly-plastic) behaviour for stainless steel as for carbon steel in an attempt to maintain consistency with traditional carbon steel design guidance.Given the high material cost of stainless steel, improving the efficiency of existing design guidance is warranted. Improvements can be made either by calibrating the existing design procedures, some of which are based on engineering judgment and limited test data, against additional experimental results, or by devising more accurate design approaches in line with actual material response. In any case more efficient yet safe design rules are desirable.The majority of published research articles on stainless steel structures focus on the response of individual members. Due to insufficient relevant experimental data, no rules are given for plastic global analysis of indeterminate stainless steel structures in any current structural design code, even though the ductility of stainless steel is superior to that of ordinary structural steel. The controversy of not allowing plastic design for an indeterminate structure made of a ductile material is obvious in Eurocode 3:Part 1.4 where it is explicitly stated that "No rules are given for plastic global analysis" even though a slenderness limit for stocky elements is specified in the same code. Moreover, because of the lack of relevant experimental data for stainless steel frames, no specific design provisions to account for second order effects in stainless steel frames are specified in any stainless steel design code. Deficiencies in current design guidance puts stainless steel at a disadvantage compared to other materials thereby hindering its use in applications where it might be the preferred solution, had the design standards not imposed strict restrictions to its design due to a gap in current knowledge.The proposed project aims at investigating the structural response of stainless steel indeterminate structures and developing appropriate design rules, by means of experimental studies on two-span continuous beams, as well as portal frames and advanced numerical analyses. Experimental results, suitable for the validation of numerical models, will be generated and will allow a rigorous study of the ultimate response of indeterminate stainless steel structures. The accuracy of current design procedures (i.e. not allowing for plastic design or partial moment redistribution in indeterminate structures) will be assessed and the possibility to apply plastic design to stainless steel structures will be explored. It is envisaged that the proposed project will lead to design rules suitable for incorporation in EN 1993: Part 1.4.

不锈钢优异的耐大气腐蚀性和良好的机械性能使其非常适合各种结构应用，特别是在腐蚀性环境中或耐久性和低维护成本是关键设计标准的情况下。阻碍不锈钢在建筑中更广泛使用的主要缺点是其高材料成本和价格波动。然而，由于在项目寿命结束时回收或再利用不锈钢材料的潜力很大，因此当考虑到项目整个寿命期间的成本时，生命周期成本和可持续性因素使不锈钢更具吸引力。不锈钢结构的设计涵盖在许多国际设计规范中，其或者是最近引入的，或者是最近根据最近的实验测试进行了修改，从而表明不锈钢近年来受到了全世界的关注。尽管没有一个明确的屈服应力，所有现行的不锈钢设计标准都采用了等效屈服应力，并假设不锈钢和碳钢一样具有双线性（弹性、完全塑性）特性，以保持与传统碳钢设计指南的一致性。考虑到不锈钢的高材料成本，提高现有设计指南的效率是有必要的。可以通过根据额外的实验结果校准现有的设计程序（其中一些程序基于工程判断和有限的测试数据），或者根据实际材料响应设计更准确的设计方法来进行改进。在任何情况下，更有效而又安全的设计规则是可取的。大多数已发表的研究文章对不锈钢结构的反应集中在个别成员。尽管不锈钢的延性比普通结构钢优越上级，但由于相关试验资料不足，现行结构设计规范中没有对超静定不锈钢结构的塑性整体分析作出规定。关于不允许塑性设计用于由延性材料制成的不确定结构的争议在欧洲规范3：第1.4部分中是显而易见的，其中明确指出“没有给出塑性整体分析的规则”，尽管在同一规范中规定了粗壮元件的细长极限。此外，由于缺乏不锈钢框架的相关实验数据，在任何不锈钢设计规范中都没有规定说明不锈钢框架中的二阶效应的具体设计规定。目前的设计指南中的缺陷使不锈钢与其他材料相比处于不利地位，从而阻碍了不锈钢在应用中的使用，如果设计标准没有对其设计施加严格的限制，由于现有知识的差距，不锈钢可能是首选的解决方案。拟议的项目旨在研究不锈钢超静定结构的结构响应并制定适当的设计规则，通过对两跨连续梁和门式刚架的试验研究以及先进的数值分析，实验结果，适用于验证的数值模型，将产生，并将允许严格的研究不确定不锈钢结构的最终响应。将评估当前设计程序的准确性（即不允许塑性设计或不确定结构中的部分弯矩重新分配），并探讨将塑性设计应用于不锈钢结构的可能性。预计拟议项目将产生适合纳入EN 1993：第1.4部分的设计规则。

项目成果

12.14: Ultimate response and design of stainless steel continuous beams

12.14：不锈钢连续梁的极限响应与设计

• DOI: 10.1002/cepa.414
• 发表时间: 2017
• 期刊: ce/papers
• 作者: Kokosis G

Plastic design of stainless steel continuous beams

不锈钢连续梁的塑性设计

• DOI: 10.1016/j.jcsr.2018.03.025
• 发表时间: 2019
• 期刊: Journal of Constructional Steel Research
• 影响因子: 4.1
• 作者: Gkantou M