A separate series of prototype tests was designed to examine the overall behavior of a precast frame sub assemblage to the slab-beam and column connections. Two sets of tests have been carried out to investigate the effect of composite action in reducing the angle of rotation of the edge beam (compatibility torsion between floor slabs and edge beam). Four factors were thought to be important in the composite behavior of the precast concrete assembly, including: (1) The type of loading(whether single or symmetric). (2) Relative rotation of beam and column and crack width in the top of the beam-to-slab interface. (3) The angle of twist in the edge beam. (4) The strength of the concrete grout in the beam-to-column connection. Tests results have shown in general that no significant increase in crack width and relative displacement slip) in the joint between beam and slab were found. Consequently there is structural continuity (composite action) between beam-slab during the loading upto the shear failure in the slabs. When this failure took place, the crack width in the top and slip in the soffit of the beam-to-slab interface increased rapidly. This can be expressed as a breakdown of the structural continuity (composite action) between beam and slab.
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