Abdul Aziz Ansari

Behaviour of Baked Clay Structural Beam Panels

Reinforced cement concrete found wide acceptability all over the world during past more than hundred years as major material of construction. But due to escalation of cost of steel and cement and particularly the transportation charges for bringing these materials of construction to the sites in the distant areas where the soil is clayey in nature (in the plains), it could be more beneficial and economical to produce baked clay panels of structural members for swift and economical construction without sacrificing the strength and durability of the buildings. Visualizing the future construction in the rural areas at relatively cheap and affordable prices, a large number of beam panels were cast, baked, post reinforced, cured and tested. The results of that experimental study have been presented in this paper. In order to determine the shear/flexural strength of baked clay alone no vertical reinforcement or anchorage steel was provided. The study was carried out in terms of modulus of rupture, shear/ flexural behaviour, mode of failure, crack pattern and ultimate load of baked clay beams. However, fundamental structural properties and material constants i.e. crushing strength, Poissons ratio and modulus of elasticity of the material cut from the beams after testing them, were also determined experimentally. The results are encouraging. However, from these tests it is found that shear strength is the dominant factor. Complete details are given in the following sections.

Strength of Wall-Slab Junction with New Form of Shear Reinforcement in a Laterally Loaded Tall Shear Wall Building

Very high concentration of flexural, shear and torsional stresses occurs at the wall-slab junctions in a laterally loaded tall building consisting of planar walls and coupling slabs. Due to this concentration of stresses and their interaction, there are great chances of failure to occur at the junction. Also the flexural stresses are not uniformly distributed and have the highest intensity near the periphery of inner walls but are reduced drastically as we move away from the wall-slab junction. Numerous attempts have been made to strengthen the wall-slab junction by using various types of shear reinforcement to ensure that shear failure should not occur. Various methods including fibre reinforcement consisting of twins of twisted steel couplets have already been used. This paper describes a new method of placing 2 inch wide flange I-sections at appropriate locations to improve the shear strength of the wall-slab junctions. Based on systematic research, a new procedure has also been developed to assess the strength of wall-slab junction using the new reinforcement method. Test results showed that a substantial increase, up to 57%, in the shear strength of specimens was obtained by using the new method of shear reinforcement in a laterally loaded tall building.

SHEAR AND FLEXURAL BEHAVIOUR OF R.C. SECTIONS WITH INDIGENOUS AGGREGATE

In all, fourteen RC beams were tested to study the shear as well as flexural behaviour of concrete with brick pieces as coarse aggregate. The experimental work is divided into four groups; two for shear and two for flexure. Both, for shear and flexure, one group each respectively was cast with stone aggregate for the sake of comparison. Full non-linear analysis of all the beams was performed with the help of a three-noded, isoparametric, layered, one-dimensional element with smeared layer of steel, using constant stiffness matrix. All the beams tested during this study were simply supported and only a single point load was applied at the centre of the effective span. The behaviour was studied in terms of load-displacement history, distribution and redistribution of compressive stresses in concrete at the point under the load at different stages of loading, crack pattern, mode of failure and ultimate load.