Task

a)    Investigate and describe the significance of the following:

i.    Slenderness ratio and buckling in columns

ii.    Effective length of columns

b) Explain Euler's critical buckling formula and its application

Task

a) Compare the load carrying capacities of a timber and a reinforced concrete column both 3m effective length and 300 mm square. The timber is SC4 Class and the reinforced concrete column contains eight 25 mm diameter bars. (permissible stress in concrete = 6 N/mm² while permissible stress in steel = 125 N/mm²).

b) A short steel post consisting of a 203 x 203 x UC60 carries three loads, as shown in Figure below. Calculate stress at each of the corners A, B, C and D.

Task

a) Determine the critical Euler buckling load of a solid aluminium rod of 12 mm diameter if it has a length of 1.0 m between pin-ended supports. (E = 70000 N/mm²)     

A post made from SC2 class timber of 4.45 m effective length is required to support an axial load of 25kN. Determine suitable dimensions for the cross-section of the post.