Precast/Prestressed Girder now designs the interior region of the deck as per the Empirical method specified in LRFD Art. 9.7.2 and the Approximate/Strip method specified in LRFD Art. 4.6.2. You can specify the rebars in the top and bottom of the deck in both transverse and longitudinal direction, and the program checks against the required steel. The Empirical method is only applicable in cases where certain design conditions as specified in the LRFD are satisfied. These criteria are listed on the tab, and if the program automatically either assumes, computes or verifies compliance with a criteria, a green check mark is added under the C (i.e. computed) column. You can manually override certain condition checks by checking the available check box under the M (i.e. manual input) column.

In the Approximate/Strip method, Precast/Prestressed Girder checks transverse flexure for positive and negative moments, crack control for positive and negative moments (i.e. transverse bottom and top reinforcement) as per Art. 5.7.3.4, longitudinal shrinkage and temperature reinforcement at top (Art. 5.10.8), and longitudinal distribution reinforcement at the bottom (Art. 9.7.3.2). The positive and negative moments due to transverse live load placement are obtained from LRFD Table A4-1. The transverse dead loads are computed based on wl2/12 or wl2/10 or a user input factor. For bridge cross sections with different girder spacings, the maximum girder space is used so as to maximize the load effects.

Figure 1 Deck Design Tab

Following are some of the assumptions and limitations in the Deck design method:

Figure 2 Deck tab