Applicability of ComBAR for crack width limitation in floors of parking garages

ABSTRACT

For the use in a specific floor system of parking garages GFRP rebars (ComBAR) with a diameter of 8 mm were studied at Kaiserslautern University. Due to the small concrete cover and the aggressive impacts the application of non-corrosive reinforcement is necessary in this system. The crack width has to be limited in order to avoid the penetration of corrosive chlorides. The suitability of an alternative to stainless steel reinforcement for the limitation of crack width in the slabs was checked in this study. The bond performance of the rebars in the typical concrete and the typical bar position was studied in pull-out-tests with short anchorage length. A mathematical description of bond behaviour due to Model Code 90 [2] was used for prediction of bond length and crack width in the slabs. The results of these calculations were verified by additional tests with large anchorage length. The influence of the concrete cover was also examined. The cracked in-plane stiffnesses could be determined by extensional tests. Those results were used to calculate the internal forces for a full size test. Finally the performance of the GFRP reinforcement system in the slab was tested with a full size test of a slab segment. In this test the loading history of car park buildings was passed through in order to gain test information about the change in crack width between different loading situations. This information is necessary for the selection of appropriate concrete coatings to ensure durability of the slabs during lifetime.