Bending Moments in Beams of Two Way Slab Systems
Two way slabs are slabs in which the surface load is transferred in two directions. Two way slabs have many types: slabs supported on beams between all columns, slabs without beams and waffle slabs. Slabs with beams are commonly used for high loads and or large spans. The deflection in the slab panel depends mainly on the beams stiffness. The deflection at middle of panels decreases as the stiffness of the supporting beams increases. The internal forces and especially the bending moments are increased in the beams as their stiffness increases. This paper will illustrate the sequence of increase in beam moments as the beams stiffness increases. Slabs with different beams stiffness and longer span to short span ratios will be studied. Also, the principle of 45 degrees- load- distribution principle for beams will be discussed. The computer program sap2000 will be used in structural modeling.
