Efficiency of the filled cores in improving the shear capacity of prestressed hollow core slabs

Abstract

ABSTRACT: Hollow core slabs correspond to one of the most advanced precast unit types. Its use in civil construction represents a reasonable progress in constructive terms, allowing the rationalization and technical improvement of the works. To ensure some improvement of the shear strength of prestressed hollow core slabs it is common to fill the cores in the slab end region. However, this corresponds to a complex activity, there is no standardized technique that enables an adequate filling, and when deficient, it prevents the work of section as composite, affecting the improvement of strength considered in the design. This article presents a study of the efficiency of the filled cores with related to the improvement of the shear capacity considering hollow core slabs with 200 mm height. So, an experimental study was carried out with the use of two types of concrete: plain concrete and fiber reinforced concrete (SFRC). Furthermore, slabs with two and four filled cores were analyzed. the theoretical values were determined according to NBR 14861:2022. From this study, it was possible to observe that the filling of two cores with SFRC improved the shear strength by 46% when compared with slabs without fillings. Thus, it was found that a greater number of filled cores was not guarantee an increase of strength proportional to the increase of the concrete area.