 The effects of loads and moments on structures are determined through structural analysis.A steel structure is composed of structural members that are made of steel, usually with standard cross-sectional profiles and standards of chemical composition and mechanical properties.The depth of steel beams used in the construction of bridges is usually governed by the maximum moment, and the cross section is then verified for shear strength near supports and lateral torsional buckling (by determining the distance between transverse members connecting adjacent beams).