Master of Engineering (Hons.)
Department of Civil and Mining Engineering
Nasralla, Talaat, Behaviour of precast concrete wall-floor slab connections under static loading, Master of Engineering (Hons.) thesis, Department of Civil and Mining Engineering, University of Wollongong, 2000. http://ro.uow.edu.au/theses/2420
Precast concrete design and product qualities are most effective in the growth of the precast industry. Zeolite concrete is one of the factors, which will contribute m improving the quality of many precast structural elements such as walls, beams, etc.
This thesis is in two parts. The first part presents a study of fresh concrete properties, which are water content, slump, strength and cost of product. Tests were undertaken in four groups of concrete adopted. The first group (B) was of a standard mix proportion of 30MPa. The second group (F) had partial replacement of cement with fly ash. The third group (S) had partial replacement of sand with granulated blast-furnace slag in a concrete mix that had the highest strength obtained from group (F). The fourth group (Z) had partial replacement of coarse aggregate (blue metal) with zeolite in a concrete mix that had the highest strength obtained from groups (F) and (S) to evaluate the effective of adding zeolite in fly-ash-slag concrete.
Zeolite in concrete is seen to improve the freshness (workability) and hardness (strength) properties of the fly-ash-slag concrete.
The second part of the thesis considers a particular connection. Connections are most important for precast structural elements. This thesis presents a study of strength and deformation behaviour of floor-wall connections in precast reinforced concrete walls in a plant building.
Three half-scale walls and floors moulds were designed, built and tested in the structural laboratory to evaluate the deflection, strain and stress behaviour of steel connections, fixing bolts, walls and floor edge beams. The design of the walls was based on the structural analysis of precast concrete walls of a one storey plant typical of a commercial building.
The load analysis and design of the concrete walls, steel reinforcement, steel connection and fixing bolts, their configuration and manufacturing were according to Australian standard recommendations.
The three tests undertaken had different types of concrete strength. The first two walls had different types of reinforcing steel and different steel connections. The third wall, adopted after the first and second walls were tested and evaluated, allowed reasonable evaluation of the deformation behaviour.
The load-deflection and strain curves of wall, floor, connection and fixing bolts were compared between the laboratory tests and the computer analysis using Strand6 program. Also the rotation of the floor slab when failure occurred was evaluated to determine its effect on the behavior of the connection and the wall.
The connections and walls demonstrated satisfactory moment resistance and shear capacities. The test results confirmed that this connection and fixing bolts would give satisfactory load capacity and ductility performance, and that they can safely carry the applicable loads .. The connection can be safely applied to precast reinforced concrete elements in a commercial building.
The crack behaviour for the three walls was studied, and conclusions were made, based on the test results and the analysis of computer results. Recommendations for future work are also given.