DefinePK

Abstract

The performance of structures under normal service loads refer to serviceability limit states which is concerned with the uses and occupancy of structures. The magnitude of deflections is the main considering of serviceability. In the present study, the finite element method was used to find the instantaneous deflection of reinforced concrete two-way homogenous solid reinforced concrete slab which is experimentally tested by Piotr. Fully material nonlinearity for both concrete and rebar was conducted firstly by considering plastic deformation, yielding and cracking. Secondly nonlinear simplified cracking method was implemented according to ACI 318-05 Chapter nine. Finally the stiffness modifier method which is mentioned in Chapter ten of ACI 318-05 for immediate deflection was also used based on reducing the flexural rigidity of the slab by the ratio of 0.25 of the total rigidly. The present work was observed that the instantaneous deflection recorded throughout the precisely modeling finite element method is strongly underestimated at ultimate loading level. While, the nonlinear simplified cracking method gave a slightly overestimated immediate deflection value at same load level. Finally the stiffness modifier method significantly underestimated the immediate deflection at also ultimate load level. It only caught the experimental deflection values at load level of 32 kN/m2 when the rebar slightly over yielding.