When the loads and span are large, plate girder sections either with riveted/bolted connections or welded connections may be provided. The number of flange plates can be increased depending upon the moment to be resisted. If depth is limited and loads are too large, welded box plate girder is provided. A box girder with riveted/bolted connections can be provided but it is too costly as compared to welded one. Box girders have great resistance to lateral buckling