Comparison of Pre-Stressed Hollow Core Slab and Precast Concrete Beams- Hcb Slab System

Abstract

A prestressed hollow core slab element studied in this thesis is a precast prestressed concrete member with continuous voids provided to reduce weight and, therefore, cost and, as a side benefit, to use for concealed electrical or mechanical runs. Primarily used as floor or roof deck systems, hollow core slabs also have applications as wall panels, spandrel members and bridge deck units. This system of construction does not require form work and Propping during installation. Precast, prestressed concrete floors offer significant advantages in many types of building construction. They offer design, time and cost advantages over other flooring materials and systems and are suitable for use with all structural systems, i.e. concrete, masonry and steel In our country precast prestressed concrete elements are not widely used for construction of most buildings. The conventional cast in-situ construction require lots of formwork and construction time, and also the precast beam-slab system construction require propping and construction time too which increases the total cost of a project. When precast prestressed hollow core slab elements are introduced in vast amount in the construction of buildings, an economical construction could be achieved. The economy of the generalized hollow core slab system is require a short construction time compared to precast beam slab system and in the quantity of slabs that can be produced at a given time with a minimum of labor required. Each slab on a given casting line will have the same number of pre-stressing strands. Therefore, the greatest production efficiency is obtained by mixing slabs with the same reinforcing requirements from several projects on a single production line. This implies that best efficiency for a single project is obtained if slab requirements are repetitive. In the present study, the advantages of prestressed hollow core slab elements, for construction of the floor slabs of four story building, is shown by making cost comparison between the precast beam-slab system and pre-stressed hollow core slab system. For this  purpose, the same span length is chosen for the two slab systems. These elements are designed for loads they should sustain when used in the construction of slabs. Finally cost comparison is made between the two systems of slab construction. The cost comparison showed that the prestressed hollow core slab system of construction is more economical and faster than the precast beam-slab system.