Write a short note on timber supports
Timber supports Timber support are heavy,bulky,costly,time consuming,of short life and indefinite strength,and use of timber has involves cutting tress.Therefore they have been replaced by steel supports to a large extent.They are still used in many situations for example: Cogs at goad edges and junction.Two cross bars on cogs at roof ledges. Vertical props with lagging at pillar sides having tendency to spall.Inclined stay props to support overhangs. Support of faults,slips,breaks in roof by cogs on either side with cross bars across them. Support of isolated spots in roadways by props,cross bars or cogs as required.As temporary supports. Statutory requirements for timber supports Props:diameter atleast 15cm,set on sound foundation and kept tight against the roof.Lid width not less than prop dia,thickness at least 8cm,length at least 50cm,When set on sand shall be on flat base piece not less than 5cm thick,50cm wide,75cm long.Set normal to floor in...