Concrete Edge Failure of Headed Stud Anchors under Fire and Post-Fire Conditions: Verification of a 3D FE Code

Fire tests were conducted at University of Stuttgart to investigate the capacity of headed stud anchors under shear load perpendicular to free edge of concrete members. The headed stud anchors were cast in concrete with various edge distances, embedment depths and diameters. The specimens were specially designed so that the anchors could be loaded in shear after 90 min (hot state) of fire according to ISO 834. Reference tests and post-fire tests on the corresponding anchors were also conducted to make comparative analysis. More importantly, numerical analyses based on a three-dimensional thermo-mechanical constitutive model for concrete that was implemented into a three-dimensional finite element code were performed to simulate experimental tests. The main aim of the paper is to verify numerical model based on the performed experimental tests. It is shown that the numerical analysis is able to predict the thermal and structural response of headed stud anchors cast in concrete close to edge very well. Based on the experimental results and numerical verification, the modification of the current formula according to Eurocode 2 for concrete edge failure of headed stud anchors under 90 min of fire is proposed.