design a combine rectangular footing for two columns A and B carrying loads of $500$ and $700$ kilo Newton respectively colum a is $300$ into $300$ mm in size and column b is $400$ into $400$ mm in size the centre to Centre spacing of the column is $3\mathrm{.}5$ M take SBC of soil may be taken as $150$ Newton per metre square use m$25$ grade concrete and hysd steel of grade fe$415$