Calculation of test load and load utilization of steel reinforced concrete columns in fire tests

Abstract

Abstract

Calculating the test load is a key aspect of conducting column fire tests. The level of applied load affects the load-bearing and deformation behavior as well as the failure time of the structural element in a fire test. Therefore, the test load also influences the fire resistance classification of steel reinforced concrete columns. A literature review shows that there are significant differences in the methods used to calculate the test load. Furthermore, documentation of the methods used is often incomplete. This makes it difficult to trace and compare test results. This contribution analyzes and compares the various approaches to calculate the test load for fire tests of steel reinforced concrete columns, based on normative standards. It is focusing on evaluating the effects of different stress-strain models for concrete (parabola-rectangle diagram and parabolic approach) and the material strengths used (tabulated values according to Eurocode and experimentally determined values) on the load-bearing capacity at ambient temperatures and the derived test load. Recommendations are formulated based on comparative calculations, for a standard-compliant, transparent and practical determination of the test load that considers both safety-relevant and economic aspects.