SHEAR CAPACITY OF PRE - STRESSED HOLLOW CORE SLABS UNDER CONCENTRATED LOAD

Precast pre - stressed hollow core (PHC) slabs are considered one of the best structural systems capable of covering large spans with minimum overall thickness and weight, and its ease of manufacturing and installation. The shear resistance of PHC slabs has not been well discussed in the different current codes. The codes have a general shear design approach. However, th e shear behavior of PHC slabs is different from that of ordinary concrete elements with shear reinforcement. On the other hand, the design models of PHC slabs in current codes does not take into consideration the significant effect of concentrated load at transfer zone as well as no method to classify the expected mode of failure. In this research, a new proposed relationship is developed to calculate shear capacity of PHC slabs. Also, the significant effect of variation of concentrated load width with resp ect the slab width will be studied. The proposed relation will be verified for different slab thickness, level of pre - stressing, concrete strength, and for solid net area of PHC slabs. Instead of performing a costly experimental study to find out whether t he effect of different factors on the prediction of shear behavior of PHC slabs, a numerical model (ANSIS 11) can be used after calibrating its accuracy with experimental data of two pre - stressed hollow core slabs. The comparisons are made for load - deflect ion curves, failure loads and crack patterns. The accuracy of the finite element models which is assessed by comparison with the experimental results was in good agreement