Lessons learned from the testing of RC frames with masonry infills and proposals for new solutions

Abstract

The vulnerability of unreinforced masonry walls (URM) under seismic events, causing huge loss of money and human lives, has revealed the enormous need for an efficient strengthening material. In this context, the present paper presents the experimental research that has been carried out with the aim of a better insight of traditional masonry infill walls commonly built in Portugal. The experimental research includes: (1) shaking table tests on reduced scale reinforced concrete (rc) building with masonry infills with distinct typologies, from traditional to solutions with enhanced properties and solutions to improve the seismic behavior; (2) in-plane static cyclic tests on an representative one storey and one bay rc frame with masonry infills with distinct typologies but similar to the ones tested in the rc building models. It was concluded that the typology of masonry walls influences global behaviour of rc buildings, particularly if no connection exist between masonry infills and rc frames. If not appropriately designed, the masonry infill walls can have a harmful influence on the rc columns by inducing shear stresses. From the in-plane cyclic tests, t was concluded that rendering takes a central role on the lateral strength and stiffness. Additionally, it was observed that bed joint reinforcement and reinforced rendering are important measures to control damage but do not influence significantly the in-plane lateral strength and stiffness.