AASHTO LRFD Load Rating Floorbeam-Girder Type Bridge in LARSA 4D Software

[Noob_Engineer]

Hi,

I'm modeling a floorbeam-girder type of bridge where a steel deck sits between the main girders directly on the floorbeams. The railings are attached directly to the girder top flanges. I'm having a great deal of trouble modeling it in LARSA 4D for the model to capture the load path properly and set up the influence surface for load rating purposes. I initially started modeling the girders and FBs as beam elements but eventually deviated towards modeling the webs of the members as shell elements and flanges as beam elements. That's the only way I was able to get the deck weight to be applied to the floorbeams directly. Now I am getting errors when I set up bridge loading data per the bridge module. I get this error "object value or With block variable not set Err Line #0". I'm hoping someone who has experience with LARSA 4D or similar softwares and have modelled a similar type of bridge could give me some pointers!

Thanks in advance!!!

 

[BridgeSmith]

I don't know anything about Larsa, but if there's no barrier between the sidewalk and the traffic lane, if I'm not mistaken, you'll need to consider the loading case where the truck is on the sidewalk, which would be the controlling case for the girders.

If the deck panels are discontinuous at the floor beams, getting the floorbeam loading is very simple - it's just the tributary length equal to the floorbeam spacing. Any effect from lateral distribution through the deck panels is likely to be negligible. I wouldn't bother with an FEM model for something this simple.