CHAPTER ONE

1.0 INTRODUCTION

A beam being a horizontal member that carries the roof floor slab, walls above and/or secondary beams. It transmits the imposed load including the self weight to the walls or columns supporting it. Beams could be reinforced concrete, wooden steel girders.

Reinforce concrete, as a composite material, has occupied a special place in the modern construction of different types of structures due to its several advantages.

Concrete is a mixture of fine, coarse aggregate, water and cement. The water hydrates the cement and harden concrete is created.

Plain concrete are stone like  material made by mining  cement fine aggregate, coarse aggregate and water with specific proportion and sometimes other addictives to increase the property of concrete in this state, the concrete is good in compression and lacks tensile strength, if it subjected to bending, the upper portion will be tensile which makes the concrete crack.

The introduction of reinforcement to  concrete reduces the effects of cracking,. The knowledge of reinforced concrete was developed many years ago. It look the advent of the industrial age where mass production of steel, cement and aggregate mining become common practice t develop reinforce concrete to become the  building material  of choice.

 

Reinforced concrete is used in bridges, building, dams, foundations and even sculptures.

This material has several advantages over steel or timber for many applications. Concrete can easily be molded into any shape.

Concrete is hard, durable, and nearly inert and provides excellent corrosion protection for the steel reinforcement. To have the best of concrete, the tensile reinforcement is cast into the concrete.

The added reinforcement provide the needed tensile strength to compliment the concrete compressive strength stiffness. The design of the reinforced concrete structures are the assembly of several basic structural element such as beam, columns,    slabs, walls and foundation.

The designer has to learn the design of these reinforced concrete element. The joints and connection are then carefully developed.

Design of reinforced concrete started in the beginning of last century following purely empirical approach. Thereafter rigorous elastic theory came out where the levels of stresses in concrete and steel are limited so that stress – deformations are taken to be linear .

1.1 BACKGROUND OF THE STUDY

The average person thinks that concrete has been in common use for many centuries, but such is not the case.