Test on Slip Coefficient of High-Strength Bolted Slip-Critical Connections after Fire

Abstract

Fire safety is a major concern with steel structures. Actually, steel structures were not fatally destroyed in most cases of fire. These damaged steel structures may be reused after structural inspection, safety appraisal and necessary repair. Bolted connections are the most widely used connection in steel structures. Slip coefficient is a key parameter to calculate the slip bearing capacity of bolted slip-critical connections. Currently there are few research results available about slip coefficient of bolted slip-critical connections after fire. To obtain the effect of heating and cooling on slip coefficient, a series of slip load tests on connections that had been heated and cooled to ambient temperature were carried out in this study. Methods of friction surface treatment included shot blast and painting inorganic zincs after shot blast. Test results show that heating and cooling have a great effect on slip coefficient of connections with two methods of friction surface treatment, among which effect on connections with shot blasting surfaces is more significant.

Mechanical Behavior of High-Strength Bolted Joints Fabricated from Fire-Resistant Steel at Elevated Temperatures

“…Król and Wachowski [7] found that the temperature level of the fre, fre duration, and fre-fghting method signifcantly afect the bolts' mechanical properties. Lange and González [8], Lou et al [9], and Zhu et al [10] studied the mechanical properties, slip coefcient, and pretension force of high-strength grade 10.9 bolts at high temperatures. Hanus et al [11] investigated the mechanical behavior of high-strength grade 8.8 bolts under the situation of "nature fre," which means a temperature history including both heating and cooling phases.…”