Toward Consistent Prediction of Web-Shear Capacity for Hollow-Core Slabs Using Strut-and-Tie Models

This paper proposes an analytical solution based on a strut-and-tie model (STM) for RC deep and short beams to predict the web-shear capacity of precast prestressed concrete hollow-core (PCHC) slabs. The proposed solution is applicable to PCHC slabs within a wide range of slab thicknesses and shear-span-to-effective-depth (a/d) ratios. Additionally, the model accounts for different cross-sectional properties of this type of slabs, geometric properties of longitudinal voids, and diameters and transmission length of prestressing strands. The proposed STM was validated against a database of 46 tests on PCHC slabs, whose capacity was also predicted using shear equations from current standards. In addition, this research investigates effects of a/d ratio and assumed depth of compression zone on shear-strength predictions for PCHC slabs. In summary, based on comparison between experimental data and analytical results, it can be concluded that the proposed STM approach is capable of providing predictions for PCHC slabs that are as reliable as current code methodologies. In addition, a direct noniterative STM approach is proposed as well to avoid challenges of iterations and refinements.