I am using the LEAP Bridge Substructure module to design a pier for a continuous 4 span structure using HS20 LFD loads.
In the AASHTO Standard Specifications, it gives you a few options for the loading. One is that you can use a lane load with one concentrated load. Another is that you can use just the truck load. A third option is using the lane load one concentrated load in two different spans, but this option can only be used for determining the maximum negative moment in the design of continuous spans. The third option is talked about in AASHTO Standard Specifications Section 3.11.3.
I used the live load generation ability to come up with my live loads. I selected the "HS20 truck" and "H20/HS20 Lane Load" for my vehicles. I then selected "Compute Continuous Beam Reaction." By selecting these options, I want to make sure that the program will use two concentrated loads for the "H20/HS20 Lane Load" option when determining the reactions because the structure is continuous and the pier is in the negative moment region.
Thanks
Rob
Answer Verified By: Rob Whiteside