I have two I-beams with full depth concrete sandwiched between them modeled in RAM Elements. The concrete is only supported by the beams; I am getting a moment of 458 k-ft. per beam from RAM Elements, while manual calculation indicates the moment is about 610 k-ft. per beam. This is part of a more complex model and I need to include the concrete in the model so the stiffness can be accounted for in deflection and load distribution computations. I tried modelling with STAAD pro and got similar results.
Moment from the lateral wind load also looks weird. Any ideas why the moment from RAM Elements is so far off the theoretical value? How do I model this to get the correct member forces? The model is attached.