Factors governing the shear response of prestressed concrete hollowcore slabs under fire conditions

Abstract

This paper presents results from numerical studies on the effect of critical factors governing the shear response on prestressed concrete (PC) hollowcore slabs exposed to fire. A validated three dimensional finite element model is applied for evaluating failure of fire exposed prestressed concrete (PC) hollowcore slabs under different limiting states, including through shear. This model accounts for temperature induced property degradation in concrete and prestressing strands, cracking in concrete, varying fire exposure, loading and restraint conditions. The factors varied in the parametric study include, slab depth, load level, loading pattern, axial restraint, level of prestressing, and fire scenario. Results from parametric studies show that slab depth, load level, loading pattern, axial restraint, level of prestressing and fire scenario have significant influence on the fire response of PC hollowcore slabs, and failure under these conditions can occur through shear limiting state prior to reaching flexural limiting state. Results from parametric studies are further utilized to propose a simplified approach for evaluating shear capacity PC hollowcore slabs under fire conditions.