Shallow flat soffit precast concrete floor system

It is a key economic criterion for multistory residential and office buildings to have a shallow floor that minimizes floor height and saves in the cost of architectural, mechanical, and electrical systems. This paper presents the development of a new precast concrete floor system that eliminates the need for column corbels and beam ledges while being shallow. The proposed system can achieve a span-to-depth ratio of 30 and flat soffit while being consistent with prevailing erection techniques. The proposed system consists of continuous precast columns, prestressed rectangular beams, hollow-core (HC) planks, and cast-in-place composite topping. The paper presents the construction sequence of the new system and focuses on testing HC-beam connections without ledges in a full-scale specimen. Testing results indicate that a 30-cm-deep flat soffit precast floor system has adequate capacity to carry gravity loads (including 488 kg/m² live load) in a 9.14-×9.14-m bay size. Also, testing shows that shear capacity of the proposed HC-beam connections without ledges can be accurately predicted using the shear friction theory.