a) Designers can use various formulae to take account of slenderness, but you should remember that their effect is simply to reduce the safe load. Calculate the slenderness ratio of a short timber strut 2m long with cross-sectional area of 75mm x 100mm. Express your average in ratio. AP,9 b) These are possibly the most widely used structural members in building. Floor joists, lintels, binders, ceiling joist, rafters, and purlins, although referred to by their own special names, are all beams. They may be defined as structural members supported at both ends and carrying a load over a space or opening. It may be said that the strength of timber beam varies directly as its width and as the square of its depth. The square of its depth means the depth multiplied by self, and applied to breadthxdepthxdepth BD2 the measure of strength may be expressed as; span L Mention the layer in between the beam that neither reduces nor elongated after bending. EV,8 c) Steel reinforcement bars, which are made from mild steel, are used to resist the tension forces in concrete. They also control shearing in beams. The thinnest bars, used for making stirrups to hold other bars in position, are 6mm in diameter. Reinforcement bars range in diameter from 10mm to 25mm. Other bars which are called deformed bars are made with patterned surfaces to increase the bond between the steel and the concrete in highly stressed conditions. If the steel and concrete could bond well, then state the differences between the coefficient of thermal expansion of steel and concrete. AN,8