Dimensioning

Top slab cut distance (t1) and bottom slab cut distance (t2) are user-defined dimensions which specify the depths of the top and bottom slab portions of a box girder used for design, as shown in Figure 1:

Figure 1: Top and bottom slab cut distance

Computation

Computation depends on these slab cut distances as follows:

• Equivalent slab thickness is evaluated, assuming a rectangular shape, based on slab area and width (t _slabarea = A _slab / b _slab).

• Dimensions dictate the sectional polygon, used to compute slab tributary area for each girder web. The tributary region includes all material above the top slab cut and half-way between girders. Exterior girders include the entire outside cantilever. Top and bottom slab-cut dimensions may be different at interior and exterior girder locations.

Please refer to the Bridge Superstructure Design Manual for additional details.