EXPERIMENTAL STUDY OF POST FIRE PERFORMANCE OF HIGH-STRENGTH BOLTS UNDER COMBINED TENSION AND SHEAR

摘要

The post fire performance of high-strength bolts is of special interest when a building structure is evaluated after an event of fire.In contrast to conventional structural steel, high-strength bolts do not recover their original strength and material properties.For the evaluation of complete building structures the behaviour of the joints and the used bolts is therefore essential.Previous tests on grade 10.9 bolts under pure tension have been conducted at the TU Darmstadt.Based on these tests reduction factors to calculate the remaining load bearing capacity were stated.Further tests on grade 10.9 bolt sets under combined tension and shear were carried out to verify if the stated reduction factors are also valid for shear and combined tension and shear.For these tests grade 10.9 bolts were heated to temperatures up to 900°C and tested under different tension-shear-relations after cooling.