Efficiency of Reinforced Concrete Structures with Mixed Reinforcement

ABSTRACT

The combined versions of a constructive solution to the reinforcement of pre-stressed concrete beams are considered in the article. Due to joint use of the prestressed and non-prestressed reinforcement, and also bentup prestressed bars it is possible to get effective reinforcing of the bending elements in case of which the outline of a materials curve will be close on an outline of curve of the bending moments from external loading, and as a result reduction in cost of structures due to saving of an expensive high-strength reinforcement and reduction of metal consumption of power forms due to simplification of the devices necessary for a bars tension. Besides reduction of the prestressed reinforcement amount allows avoiding destruction of concrete at end of beam and formations of cracks on the upper side of a beam at its production.

For the studying of the stress-strained state pre-stressed beams and reinforced concrete beams with mixed reinforcement, and also for determination of efficiency of its application, by means of methods of finite element modeling were analysed three versions of the constructive solution of reinforcing of beams: the first – with prestressed bent-up and straight bars, the second – with prestressed bent-up and non-prestressed straight bars and the third – with non-prestressed bent-up and straight bars.

In the proposed constructive solution of reinforced concrete beams consumption of high strength reinforcement is reduced due to application of mix prestressed and non-prestressed reinforcement at the support. Use of the bent-up prestressed reinforcement at a support allows increasing shear resistance for 10 %, and cracking resistance for 40 % in comparison with a non-prestressed beam.

Keywords: bent-up reinforcement, prestressed beam, crack resistance, bearing capacity, finite-element modeling.



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