Showing papers by "Katrin Beyer published in 2011"

Shear deformations of slender reinforced concrete walls under seismic loading

Abstract: Experimental results gained from quasi-static cyclic tests on 34 slender structural reinforced concrete walls available in the literature are used to examine the shear deformations for displacement demands in the inelastic range. Based on these results the distribution of shear strains within the walls and the variation of shear deformations with top displacements is discussed. It is shown that for shear walls whose shear transfer mechanism is not deteriorating significantly the ratio of shear to flexural deformations remains approximately constant over the entire range of imposed displacement ductilities while for walls whose shear transfer mechanism is degrading significantly the ratio of shear to flexural deformations is increasing. For the former a simple model is proposed which allows estimating the ratio of shear to flexural deformations.

Modelling of spandrel elements in URM structures with RC slabs or ring beams

Abstract: In many unreinforced masonry (URM) buildings reinforced concrete (RC) slabs or ring beams maintain the integrity of the building when subjected to seismic loading and redistribute forces between different URM piers. In addition, RC slabs and ring beams contribute to the global stiffness and overturning capacity of the building by acting as horizontal coupling elements between URM piers. This paper reviews current design approaches concerning the consideration of the contribution of RC slabs and ring beams to the global overturning capacity of buildings with URM piers. Numerical simulations of composite spandrels consisting of RC beam and URM spandrel are performed and the results are compared with experimental evidence from own full-scale tests on composite spandrels. Finally, different wall configurations of URM buildings with RC slabs are analysed and conclusions concerning the design and analysis of such buildings drawn.

Experimental investigation of the effect of the longitudinal reinforcement content of ring beams on the cyclic behavior of masonry spandrels

Abstract: In many unreinforced masonry (URM) buildings reinforced concrete (RC) ring beams are introduced at each storey in order to maintain the integrity of the building when subjected to seismic loading. Such ring beams also contribute to the in-plane resistance of URM walls consisting of vertical piers connected by ring beams and often also by horizontal URM spandrels. The entity of the RC ring beam and the URM spandrel is in the following referred to as composite spandrel. Although numerical simulations have shown that composite spandrels have a significant influence on the seismic behavior of URM walls, their contribution has often been neglected since vital experimental evidence on the cyclic behavior of spandrel beams was lacking. The paper discusses important phenomena affecting the cyclic force-deformation behavior observed during full-scale quasi-static cyclic tests on composite spandrels. In particular the effect of the longitudinal reinforcement content of the RC ring beam on the interaction between URM spandrel and RC ring beam as well as on stiffness, strength and deformation capacity of the composite spandrel are discussed. Based on the test results first recommendations concerning the design and analysis of RC ring beams in URM structures are presented.