Design Module 4 illustrates the design of composite, continuous multi-span steel bridges following a straight roadway alignment. The module includes detailed calculations of a 3-span plate girder bridge and a 2-span box girder bridge, which are featured in the CISC course on Steel Bridges – Design, Fabrication, Construction as Design Examples 1 and 2. Structural design aspects covered in the examples include section properties, slab reinforcement, slab casting sequence, moment resistance before and after composite action, shear resistance, cross-frame forces, control of cracking, camber, superstructure vibrations, fatigue, wind and seismic loads, and field splice design. DM4 is based on CSA Standard S6-14, Canadian Highway Bridge Design Code. Structural steel plates conform to CSA G40.21 grades 350A and 350AT.