BrDR computes the required development length of flexural reinforcement and takes this development length into consideration when it creates cross sections for export to an analysis engine. If the reinforcement bars start at the first support line of the member or end at the last support line of the member, BrDR computes the percent of bar developed at the support line to be zero percent and the cross section that exists at these locations will have zero rebar. If no rebar exists, the analysis engine cannot compute the "d" distance from the extreme compression fiber to the centroid of the tension reinforcement. If the "d" value does not exist, the shear capacity of the beam cannot be computed.
To solve this problem, first enter a value for the "End Bearing Locations" on the Member Alternative window. This is the distance from the end centerline of bearings to the physical end of the beam. Once this value is entered, the reinforcement can start to the left of the first bearing and end it to the right of the last bearing. BrDR will determine that the bars are partially developed at the end bearing lines and a "d" value can be computed.
An alternate solution to this problem is to specify the bar as "Fully Developed" on the Girder Profile: Reinforcement tab. This will cause BrDR to assume that the bar is fully developed along its entire length.
Another cause of this problem is the lack of shear reinforcement ranges being defined. Assign shear reinforcement definitions along the length of the member in the RC Shear Reinforcement Ranges window.