THE INFLUENCE OF REINFORCEMENT PERCENTAGE ON THE LOSS OF CRIMPING FORCE IN PRESTRESSED BUNDLED REINFORCED CONCRETE BEAMS.

Abstract

The issue of reducing the material consumption of structures and construction time is currently one of the most pressing challenges for builders. Many different structural solutions have been proposed. One such solution is the use of steel-concrete structures with external plate or strip reinforcement. The reinforcement bungle in prestressed concrete comprises sheet metal and periodically profiled rebars. For beam structures, the most effective approach is variable cross-sectional reinforcement along the length of the beam, corresponding to the moment diagram. For sheet reinforcement, changing the cross-section along the length requires additional efforts to cut, weld, and so on. This study examines the influence of different ratios between prestressed sheet and non-prestressed rebar reinforcements within the reinforcement bundle on stress losses in the prestressed sheet reinforcement. In the reinforcement bundle, the prestressed sheet reinforcement maintains a constant cross-sectional profile along the entire length of the beam, while the non-prestressed bar reinforcement has a variable cross-section relatively to the bending moment diagram. The use of reinforcement bundles allows for more efficient utilization of reinforcement in concrete structures. This is due to the fact that there is often an issue of uneven load distribution on structures within a single building; for beam floors, such beams must be reinforced with different frameworks accordingly. In the case of steel-concrete beams, this creates additional difficulties because the range of plate reinforcement is limited. One solution to this problem, as mentioned earlier, is the use of a reinforcement package — plates and rebars within a single beam. The area of the plate remains constant in all beams, while the quantity (area) of rebar varies according to the need. The effect is further enhanced when prestressing is applied.