Improved precast reinforced concrete crossbar of reduced height. Results of full-scale loading tests

Abstract

The object of the study is an improved design of a reinforced concrete floor crossbar as part of a prefabricated frame of a residential building. The crossbar has a reduced height with undercuts in the support zones, which in combination with modified prefabricated multi-hollow plates allows you to perform the lower surface of the overlap without protruding ribs. This solution allows you to use precast reinforced concrete with all its advantages and compete with monolithic reinforced concrete girderless frames. To ensure the strength of inclined sections to the action of transverse force and bending moment, cage using rigid inserts made of sheet steel are used as transverse reinforcement. The results of the tests showed that the developed crossbar meets the stated requirements for both the first and the second group of limit states (strength, stiffness, crack resistance). Transverse reinforcement in the form of cages with rigid inserts made of sheet steel provides the required bearing capacity of inclined sections. The test confirmed the reliable joint work of concrete and rigid inserts from the beginning of loading to the ultimate state of strength.