Influences of chord pre-stress on CHS X-joints with high-strength-steel at various temperatures

IF 3.3 3区工程技术 Q2 ENGINEERING, CIVIL

Fire Safety Journal Pub Date : 2025-08-18 DOI:10.1016/j.firesaf.2025.104506

E. Ozyurt , Y.C. Wang

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引用次数: 0

Abstract

This study examines the influence of chord pre-stress on the behaviour and load resistance of Circular Hollow Section (CHS) X-joints with High Strength Steel (HSS) at various temperatures. This investigation uses a total number of seven hundred and four Finite Element simulation results to evaluate the level of accuracy of current Eurocode and CIDECT design guidelines in predicting the high-temperature resistance of these joints. The numerical simulations investigate the effects of changing brace-to-chord diameter (β), chord semi-diameter-to-thickness (γ), and brace-to-chord thickness (τ) ratios, as well as different prestressing levels (n_p) and temperatures (θ).

The γ and τ ratios have a limited effect on the normalised joint strength, but the β ratio, and the prestressing level are highly influential. At ambient temperature, the CIDECT design approach is a more suitable method for calculating the chord pre-stress reduction factors for S355 joints. For HSS X-joints, the constant modification coefficient of 0.80 is inadequate, and this paper has proposed a new modification coefficient as a function of the pre-stress level. At elevated temperatures, the ambient temperature resistance of CHS X-joints can be modified by the reduction factor of the Young's modulus for S355 steel and that of the yield stress for S960 steel.

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不同温度下弦预应力对高强钢CHS x型节点的影响

本文研究了不同温度下弦预应力对高强度钢（HSS）圆空心截面（CHS） x形节点的性能和抗载能力的影响。本研究共使用7404个有限元模拟结果来评估当前欧洲规范和CIDECT设计指南在预测这些接头的耐高温性能方面的准确性。数值模拟研究了不同预应力水平（np）和温度（θ）对支撑-弦直径（β）、弦半直径-厚度（γ）和支撑-弦厚度（τ）比的影响。γ和τ比值对归一化节点强度影响有限，但β比值和预应力水平影响较大。在环境温度下，CIDECT设计方法是一种更适合计算S355节理弦预应力减小系数的方法。对于高速钢x形节点，恒定的修正系数为0.80是不够的，本文提出了一个新的修正系数作为预应力水平的函数。在高温下，CHS x型接头的环境温度耐受力可以通过对S355钢的杨氏模量和对S960钢的屈服应力的折减系数进行修正。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Fire Safety Journal 工程技术-材料科学：综合

CiteScore

5.70

自引率

9.70%

发文量

153

审稿时长

60 days

期刊介绍： Fire Safety Journal is the leading publication dealing with all aspects of fire safety engineering. Its scope is purposefully wide, as it is deemed important to encourage papers from all sources within this multidisciplinary subject, thus providing a forum for its further development as a distinct engineering discipline. This is an essential step towards gaining a status equal to that enjoyed by the other engineering disciplines.