Once all of the distribution factors had been calculated in accordance to the AASHTO FRFD Specifications [14] and the FEM, the percent difference was obtained in order to quantify the accuracy of the current code procedures in predicting the load distribution of a concrete girder bridge with integral abutments.
In this case, the AASHTO FRFD Distribution factor was 8% unconservative in comparison to the FEM distribution factor.
Bridge properties that are currently influenced in the calculation of the distribution factors in the AASHTO FRFD Bridge Design Specifications [14] are span length, deck thickness, edge distance, and skew.
The ratio of the FEM distribution factor to the AASHTO FRFD distribution factor shows the range in conservatism or unconservatism of the AASHTO empirical relationships.
These lengths were chosen to encompass span lengths of typical precast girder bridge lengths allowed by the distribution factor equations in the AASHTO FRFD Specifications [14].