A reinforced concrete T-beam has an effective depth of 625 mm and is reinforced with 12-30 mm diameter bars. The web width is 375 mm and has a flange thickness of 100 mm. The beam has a span of 7.5 m and center to center spacing equal to 3.5 m. fc'=21 MPa and fy = 425 MPa. Determine the effective flange width for the given section and its nominal moment capacity, Mn. Draw the final details of the design of the section.