Modeling of the precast concrete hollowcore floor diaphragm with tie beams under seismic action.

Hollowcore slabs are commonly used for floor and roofs of residential and commercial buildings. Extensive research has been done on precast structures, but only limited studies have been done on the cast-in-place diaphragm's tie-beams modeling aspects. This article presents a methodology of modeling precast concrete floor rigid diaphragm made of hollowcore slabs with the cast-in-place tie beams and evaluating its accuracy. two types of model were designed:1. whole rigid slab supported on two opposite sides only (one-way slab); 2. discrete slabs with parallel cast-in-place diaphragm struts. Designed load is q=1 t/m², for in-plane rigidity analysis the lateral force P=1 t is considered. The study slab thickness is 120 mm. The concrete class concrete B25 (E_b = 30 MPa – tangent modulus of elasticity of concrete B25; E = 18.5 MPa – secant modulus of elasticity). The analyses were conducted using the LIRA-SAPR software package. The modeling process is illustrated in detail. The diagrams of bending moments and deflections are presented, comparison between the two models was done. Both methods give correct results, reflecting the actual structural action of the precast concrete hollowcore floor. [ABSTRACT FROM AUTHOR]