Consider a cantilever beam with a load applied at the free end. The applied load creates the bending moment which is maximum at the fixed end and a shear force along the length of the beam. In the sandwich panel, these forces create tension in the upper skin and compression in the lower skin. This template will be useful in composite steel beam design.
Light Weight Composite Steel Beam Design
Basic Section info
The first section after the results summary includes the computation of the effective flange width for flexural calculations, bE, and a listing of the relevant section properties to be used in later calculations.
The given loads are “imposed” loads. In other words, these are loads that are in addition to the self-weight of the beam and slab. Consequently, it is important to re-compute the loads with every change in the steel section and slab thickness. This is a common exercise in beam design. The distributed loads are calculated as the beam weight plus the pressure loads times the beam’s tributary width.
Since we are considering both the construction & occupancy conditions, we need to compute the loads at those stages.
Steel Beam Capacity During Construction
The big concern during construction is the flexural capacity of the section without composite action. The loads supported include the weight of the beam, slab weight, and the construction live loads. In this case, the beam is stored at third points and acts as a continuous beam over three spans, substantially reducing moment and deflection. The beam is also considered to have lateral support at the ends & at the shoring supports. This results in a long laterally unbraced length that should be considered when computing the LTB limit state.