Shear Strength and Shear Stiffness of Permanenet Steel Bridge Deck Forms

Robert M. Currah and Karl H. Frank


The behavior of several types of Permanent Steel Bridge Deck Forms was studied. The tests were conducted on full scale deck panels typically 8 feet wide with deck spans ranging from approximately 7 1/2 feet to 13 feet. Loading was applied through a test frame in order to impart a shear deflection to the deck panels. The objective of this study was to examine the shear strength and shear stiffness of the deck forms included in the test program.

It is common practice to support bridge deck forms on support angles attached to the bridge girders to allow for elevation adjustment of the deck forms during erection of the steel bridge deck. The majority of the tests in this study were conducted using a rigid deck support member attached to the test frame. The results of these tests provided strength and stiffness capacities of the deck forms without any effect due to the flexibility of the deck support angle. Several additional tests were performed with the deck panels supported on support angles similar to those used in the industry today. These tests provided a preliminary indication of the effect that these support methods have on the shear strength and shear stiffness of the girder/deck form system.

Test results were compared to strength and stiffness values predicted by the Steel Deck Institute (SDI) Design Manual to determine if this design manual could be used to estimate the shear capacities of Permanent Steel Bridge Deck Forms. The SDI design equations were found to provide acceptable shear strength and shear stiffness values for certain types of Permanent Steel Bridge Deck Forms but not for all types. The results of these comparisons are presented in this report.

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