Concrete edge failure of single headed stud anchors exposed to fire and loaded in shear: Experimental and numerical study

In the present study the results of experimental tests and numerical simulations on single headed stud anchors cast in concrete member and loaded in shear against concrete edge are presented and discussed. The anchors were exposed up to 90 min of fire and loaded in shear under hot and cold conditions up to failure. The temperature distribution, load-displacement curves and failure patterns were recorded. The numerical simulations were conducted using a thermo-mechanical model that was implemented into a three-dimensional finite element (3D FE) code. The constitutive law for concrete was the temperature dependent microplane model. The results of numerical analysis, including the temperature history profile, load-displacement response and the failure load, were verified by the experimental results. Subsequently, a parametric study was carried out. The experimental and numerical results show that the shear capacity of headed stud anchors is strongly affected by the fire exposure. Especially the cooling process leads to severe loss of load capacity. It is shown that the design formula according to Eurocode 2, Part 4 (Annex D) for concrete edge failure at 90 min of fire is rather conservative for the loading in the hot state, however, it overestimates the resistance for the cold state.