1. Gross flange area for a riveted plate girder is to be designed considering net area as 80% of its gross area. Consider width of the flange as 500 mm while web plate as 1000 mm x 12 mm. The girder is to resist a maxi-mum BM of 4500 kNm. Maximum allowable bending stress in tension is 150 MPa. Gross flange area is