Nondestructive Post-fire Damage Assessment of Structural Steel Members Using Leeb Harness Method

Abstract

Abstract Assessment of steel damage is one of the key methods in retrofitting and reconstruction of the steel structures after fire. The traditional assessment method is to cut the samples from the steel members and check the levels of damage. This method will damage the structural members and the process is time consuming. In this paper, a quick, simple and efficient nondestructive detection method to measure the strength of steel after fire is developed using so called Leeb hardness method by means of establishment the relationship between the residual strength of steel members after fire and the Leeb hardness, the post-fire steel strength can be fast determined without damage to the structural members. In this paper, in total 120 Chinese H-shaped steel sections were selected for testing the Leeb hardness after fire. The influence of the parameters such as the duration of the fire exposure, cooling mode, steel grade, stress state and location of the Leeb hardness test on the test results was investigated. The relationship between the steel Leeb hardness and the parameters were developed. In addition, regression functions between the residual strength of steel members after fire and the Leeb hardness was established based on these test results which can accurate predict the residual strength of the steel members after fire, providing the engineers a new fast assessment method for the residual strength of the steel after fire.