why we use steel in constuction
Steel + Concrete = Safe Steel only = Expensive Concrete only = Are you mad? Everyone knows that concrete is damn good in compression while steel is great in tension. Steel is also good in compression but because it has very high strength, the cross section generally becomes small and the smaller the cross section the more are the chances of buckling, while concrete on the other hand has low strength so we require larger cross sections and in doing so we overcome the buckling effects. Now, the important question is why only steel? Why not aluminium? The reason is, when both the material are heated they possess a similar coefficient of thermal expansion, concrete has of the order of 14 x 10^-6 while steel has 12.6 x 10^-6. So when it gets hot, both the material experience almost similar strains and there is no internal stress formation. Now one more question comes to mind is, what would happen even if internal stresses are formed? Well, those small strains can create tensile stresses in...