Analysis and Determination of Force Effects

Per Article 9.8.2.1 of the AASHTO LRFD (7th Edition, 2014), the force effects in open, filled, and partially filled grid decks, and grid decks composite with a reinforced concrete slab can be determined using one of the following methods:

• Approximate analysis methods specified in Article 4.6.2.1, as applicable;
• Orthotropic plate theory;
• Equivalent Grid;
• Design aids provided by the deck manufacturer, if the performance of the deck is documented and supported by sufficient technical evidence.

Live load effects for open grid decks, per Article 4.6.2.1, can be determined using the equivalent strip method, similar to conventional reinforced concrete deck slabs. Filled and partially filled grid decks, and grid decks composite with a reinforced concrete slab must be designed for live load force effects computed in accordance with Article 4.6.2.1.8, as the equivalent strip method is not applicable. Additional information regarding the development of the equations provided in Article 4.6.2.1.8 and the determination of live load effects can be found in references (12), (13), and (14).