Durham School of Architectural Engineering and Construction


Date of this Version



Patent No.: US 8,671,634 B2


Appl. No.: 13/434,359


A precast concrete floor system that eliminates the need for column corbels and beam ledges while being very shallow. The main advantages of the present system include a span to-depth ratio of 30, a flat soffit, economy, consistency with prevailing erection techniques, and fire and corrosion protection. The present system consists of continuous precast columns, prestressed rectangular beams, hollow-core planks, and cast-in-place composite topping. Testing results have indicated that a 12 inch deep flat soffit precast floor system has adequate capacity to carry gravity loads (including 100 psf live load) in a 30 ft x 30 ft bay size. Testing has also shown that shear capacity of the ledge-less hollow-core-beam connections can be accurately predicted using the shear friction theory.