Mechanical properties of heat-treated high strength steel under fire/post-fire conditions

Chiew, Sing‐Ping; Zhao, Ming; Lee, Chi King

doi:10.1016/j.jcsr.2014.02.003

Cited by 208 publications

(69 citation statements)

References 9 publications

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“…Regarding their behavior at elevated temperature, limited information exists in the literature and the building codes do not include design recommendations for this type of steels in the fire situation. Only results from Lange and Wohlfeil [12], Schneider and Lange [13] and Outinen [14] on HSS S460, or Chen et al [15] and Chiew et al [16] for HSS S690 can be found. Recently, Qiang [11], [17], [18], investigated the properties at elevated temperatures of HSS S460, S690 and S960, proposing reduction coefficients of the mechanical properties of these steels at elevated temperature based on experimental results, see Fig.…”

Section: Introductionmentioning

confidence: 99%

Advanced materials for concrete-filled tubular columns and connections

et al. 2015

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The advantages of concrete-filled steel tubular (CFST) columns are well known at room and elevated temperatures, however, beyond a certain slenderness their load-bearing capacity starts to decrease. Besides, blind-bolts represent a proper system to allow endplate bolted connections to hollow steel tubular columns and CFST, although the resistance of the bolt shank conditions affects the performance of the connection. In this paper, the use of innovative materials is proposed as a method of enhancing of the load-bearing capacity for both CFST columns and connections. In this line, a first approach of the benefits using high strength steel, fire-resistant steel and geopolymer concrete applied for CFST columns in the fire situation is developed, obtaining better fire results although depending on the columns cross-sections configuration and the part where the advanced material is applied. Related to blind-bolts connections under fire conditions, the use of fire-resistant bolts is assessed. Their higher strength retention in fire could avoid the use of protection, but only in limited cases. Furthermore, a preliminary study on shape memory alloys in the blind-bolts is performed at room temperature and supporting cyclic pull-out loading.

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Section: Introductionmentioning

confidence: 99%

Advanced materials for concrete-filled tubular columns and connections

et al. 2015

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“…On the contrary, the specimens cooled in a furnace (S355J2H steel) are characterized by large dispersion, while significant reduction is observed in medium temperatures (500-600°C). As for the reheated, quenched and tempered steel (RQT-S690), an important discussion is followed by Chiew et al (2014) comparing their findings with the corresponding ones for S690QL steel, published by Qiang et al (2012a). In addition, from the investigation at elevated temperatures followed in the same study, the elastic modulus was attained poorer deterioration, compared to other materials referenced therein, while the strengths were drastically reduced.…”

Section: Post-fire Properties Of Hssmentioning

confidence: 95%

Mechanical properties of High and Very High Steel at elevated temperatures and after cooling down

2017

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High-strength steels (HSS) are produced using special chemical composition or/and manufacturing processes. Both aspects affect their mechanical properties at elevated temperatures and after cooling down, and particularly the residual strength and the ductility of the structural members. As HSS equates the design of lighter structural elements, higher temperatures are developed internally compared to the elements designed with conventional carbon steel. Therefore, the low thickness members, along with the severe effect of high temperature on the mechanical properties of the HSS, constitute to the increased vulnerability of such structures in fire. Moreover, the re-use and reinstatement of these structures are more challenging due to the lower residual mechanical properties of HSS after the cooling down period. This paper presents a review of the available experimental studies of the mechanical properties of HSS at elevated temperatures and after cooling down. The experimental results are collected and compared with the proposed material model (reduction factors) of EN1993-1-2. Based on these comparisons, modified equations describing the effect of elevated temperatures on the mechanical properties of HSS are proposed. Also, the post-fire mechanical properties of HSS are examined. A comprehensive discussion on the effect of influencing parameters, such as manufacturing process, microstructure, loading conditions, maximum temperature, and others is further explored.

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“…Overall, it is shown that the predictive equations in the literature are not suitable to predict the residual strengths of the tested cold-formed high strength steels after exposure to fire. The cold-formed high strength steel data obtained in this study and the hotrolled high strength steel data reported by Qiang et al [11,12], Li et al [13] and Chiew et al [18] were used to propose residual mechanical properties for high strength steels after exposure to fire. It is illustrated that the proposed predictive equations are suitable for both coldformed and hot-rolled high strength steel materials with nominal yield stresses ranged from 690 to 960 MPa.…”

Section: Discussionmentioning

confidence: 88%

“…Therefore, the predictive equations proposed in this study are not restricted to the materials that tested and reported herein, but can be applied for both cold-formed and hot-rolled high strength steels with nominal yield stresses ranged from 690 to 960 MPa of various steel grades. The post-fire mechanical properties retention factors of the cold-formed high strength steels obtained herein are plotted together with those of the hotrolled high strength steels [11][12][13]18] in Figs. 8-10.…”

Section: Proposed Predictive Equationsmentioning

confidence: 99%

Post-fire mechanical properties of high strength steels

Young

2018

Proceedings 12th International Conference on Advances in Steel-Concrete Composite Structures - ASCCS 2018

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High strength steels are becoming increasingly attractive for structural and architectural applications due to their superior strength-to-weight ratio which could lead to lighter and elegant structures. The stiffness and strength of high strength steels may reduce after exposure to fire. The post-fire mechanical properties of high strength steels have a crucial role in evaluating the residual strengths of these materials. This paper presents an experimental investigation on post-fire mechanical properties of cold-formed high strength steels. A series of tensile coupon tests has been carried out. The coupon specimens were extracted from cold-formed square hollow sections with nominal yield stresses of 700 and 900 MPa at ambient temperature. The specimens were exposed to various elevated temperatures ranged from 200 to 1000 °C and then cooled down to ambient temperature before tested to failure. Stress-strain curves were obtained and the mechanical properties, namely, Young's modulus, yield stress (0.2% proof stress) and ultimate strength, of the cold-formed high strength steel materials after exposure to elevated temperatures were derived. The post-fire retention factors that obtained from the experimental investigation were compared with existing predictive equations in the literature. New predictive equations are proposed to determine the residual mechanical properties of high strength steels after exposure to fire. It is shown that the proposed predictive equations are suitable for both cold-formed and hot-rolled high strength steel materials with nominal yield stresses ranged from 690 to 960 MPa.

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Mechanical properties of heat-treated high strength steel under fire/post-fire conditions

Cited by 208 publications

References 9 publications

Advanced materials for concrete-filled tubular columns and connections

Advanced materials for concrete-filled tubular columns and connections

Mechanical properties of High and Very High Steel at elevated temperatures and after cooling down

Post-fire mechanical properties of high strength steels

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