Grand Housing Development Program Volume III - Gtz

ANALYSIS OF PRECAST BEAMThe analysis of the pre-cast beamis divided into two parts.1. Initial condition2. Final conditionINITIAL CONDITIONThe initial condition is one whenthe pre cast beams are laid on themain beams supporting them,overlain by the slab HCBs, beforetopping slab concrete is cast.For spans greater than 4m a concretesection of 80mm depth and120mm width has been used.For initial condition this pre castbeam is laid on the main beamssupporting it. Since the initialcondition is a transitory period thedepth of the pre cast beam is chosenfulfilling the flexuralrequirement which is shown later.A typical pre cast beam section isshown in Fig.2.Fig. 2: Detail of precast beamFig. 3: Precast beam and HCB arrangementbefore top slab casting(initial condition )HCB SLAB DETAIL AT INITIAL CONDITIONThis precast beam is to be supported at midpoints in order to meet it’s designrequirements typical section of a pre cast beam with the hollow blocksat initial condition is shown in Fig-3.The pre cast beam at initial condition is designed to carry the live load anddead load. It is provided with shear reinforcement in accordance with thecode requirements.Typical analysis of a precast beam at initial condition: STRUCTURAL DESIGN OF COST EFFICIENT APPARTEMENTS CALCULATIONS69Addis AbabaCity Government