Creep behavior of 10. 9s high-strength bolts under and after fire

被引：0
|
作者：
Lu Y. [1 ]
Jiang J. [1 ]
Cai W. [2 ]
Chen W. [1 ]
Ye J. [1 ]
机构：
[1] School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou
[2] School of civil engineering, Hainan University, Haikou
来源：
Jianzhu Jiegou Xuebao/Journal of Building Structures | 2023年 / 44卷 / 06期
关键词：
creep behavior; creep model; fire; high-strength bolt; micro mechanism;
D O I：
10.14006/j.jzjgxb.2022.0139
中图分类号：
学科分类号：
摘要：
As an important structural component in the connection of steel structures, high-strength bolts have a high stress level and may experience creep deformation under high temperatures. This will lead to excessive deformation and failure of the connections, and affect the global fire behavior of the structure. To this end, experiments were conducted to investigate the creep behavior of 10. 9s high-strength bolts under high temperature and after fire. The creep strain-time curves at different temperatures and stress levels were obtained using DIC measurement systems. The fracture surface of the damaged 10. 9s high-strength bolts was scanned by electron microscope to investigate the micromorphology and failure mechanism of the bolts. A high-temperature explicit creep model was calibrated by the test data, and parametric studies were conducted on a T-type connection. The results show that the creep deformation of high-strength bolts is significant at high temperatures, and the creep strain is positively correlated with the temperature and stress ratio. The post-fire creep effect is minor, and the fracture of the bolts after fire is in a brittle intergranular manner represented by a cup-shaped fracture surface. The necking of bolts under high temperatures is obvious and in a ductile transgranular manner. The Field & Field creep model is suitable for characterizing the high-temperature creep behavior of high-strength bolts. The temperature, stress level, and duration time are the main factors affecting the high-temperature creep of high-strength bolts. The creep of bolts has a great impact on the fire resistance of steel connections, and ignoring the influence of creep can lead to unsafe results. © 2023 Science Press. All rights reserved.
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页码：222 / 234
页数：12
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