Structural comparison study on composite steel girder bridges between iraqi and AASHTO bridge live loads

The composite curved I-girder bridges become the preferred alternative for the designer in the design of highway interchanges and urban overpass bridges. The geometric properties of composite curved I-girder bridges (horizontal and vertical alignments) overcome the complicated site conditions, limited rights of way, and traffic mitigation. A structural analysis was carried out in this research for composite curved in plane steel girder under both Iraqi and AASHTO live loads of bridges to compare the deformations and Strains resulting from these loads. The uniform, wheels, and tandem loads, in addition to Self-Weight (SW) and the Superimposed Dead Load (SIDL) were applied to produce a maximum flexural response in accordance with both Iraqi and AASHTO bridge live loads. The structural analysis was carried out using a Finite Element (FE) method by ANSYS Workbench commercial software. Effect of curvature and girder spacing on the flexural behavior were studied in several parametric case studies of various degrees of curvature [(L/R)=0.1, 0.2, 0.3, and 0.4 radians] and for girder spacing of (1.75, 2.0, 2.25 m). The finite element results illustrate that the deflection and mid-span bottom flange longitudinal strain of girders increase when the bridge curvature increase. Girder spacing has not record a significant effect on both deflection and mid-span bottom flange longitudinal strain of girders. The deformation and Strain resulted from the application of AASHTO LRFD loads are greater than those resulted from the application of Iraqi Standard loads.