I am designing a post-tensioned straddle bent. The superstructure has 6 girder lines. Is it possible to define a design truck using fixed axle spacing so it appears "stationary" to reflect the live load reactions from girders to a post-tensioned straddle bent? For example the bearing locations = axle fixed spacing from the left end are: G1-G2-G3-G4-G5-G6 = 63.5'-7.5'-7.5'-7.5'-7.5'-7.5'.