Model Study of Beam-Slab Bridge Superstructures

The bridge type studied consisted basically of a reinforced concrete cast-in-place slab constructed to act compositely with precast prestressed concrete spread box beams. Pilot tests were conducted on a Plexiglas model simulating an existing bridge which had been previously tested as part of a series of field tests. With the model system used, dismountable Plexiglas models of a great variety of cross sections were assembled, tested, and analyzed at an average rate of four models per week. The tests were designed and conducted such that the experimental data could be subjected to a proper statistical analysis. In addition, due to the use of identical increments of load, a procedure was devised to permit the automatic correction of random errors. The various effects of beam size, number of beams, slab thickness, and presence of curb, parapet, and diaphragms are presented as a sample of the results from the testing of 26 models.