A reinforced concrete simply-supported T-beam , span length L 0 = 19.96 m , calculated span length L= 19.50 m. For concrete C30, f ck = 23.4 MPa , f tk = 2.20 MPa , and E c = 3.0×10 4 MPa. The environmental condition is type I, and the safety class is class 1 . The dimension of main beam section is seen in Figure . The class of mid-span section main rebar is HRB400 . Rebar section area A s = 6534 mm 2 ( 8Φ28+2Φ16 ) , a s = 111 mm , E s = 2×10 5 MPa , and f sk = 400 MPa. Moment , M Q 1 = 546 kN · m ( vehicle impact coefficient excluded ) , is formed by vehicle load characteristic value when T-beam mid-span section is in service ; the moment due to pedestrian load characteristic value is M Q 2 = 63.20 kN · m , and the moment caused by permanent load characteristic value is M G = 710.4 kN · m. Preliminary check crack width of reinforced concrete simply-supported T-beam.