IMPROVING STRUCTURAL BEHAVIOR OF REINFORCED CONCRETE DEEP BEAM WITH OPENING USING EXTERNAL PRE-STRESSED STRAND AND STEEL PLATE UNDER STATIC AND CYCLIC LOADING

Abstract

Openings in RC deep beams are used to pass service utilities, which decreases the load resistance capacity and stiffness of the member and it changes the behavior of the damage on the corner part of the openings. The main goal of this research is to improve the structural behavior and stiffness of RC deep beam with hole under the consideration of static and cyclic loading by using externally pre-stressed strand and steel protective. Numerical analysis is done via FEA software ABAQUS to investigate the non-linear stress strain behavior of reinforced concrete deep beams with transversal openings at various position. Ninety-six (96) RC beams with holes were modeled, from them fifty-two (52) are investigated under static loading and the rest forty-four (44) models are examined under cyclic loading. In addition to span-to-depth ratio of 1.18, 1.68, 2.18, and 2.68, pre-stressing level, steel protective thickness around holes and opening location and types are considered to explore the influence on the load carrying capacity, mid span deflection, crack propagation, stress concentration, energy dissipation and stiffness of the models. According to the results from FEA outputs, the increase in pre-stressing level on externally pre-stressed strand for reinforced concrete deep with square openings at the shear zone shows the increase in load carrying capacity by 0.171%, 6.831% and 10.1181% under static loading and decrease in mid span deflection by 8.46%, 20.336%, and 21.93%. The same models under cyclic loading shows the some significant load carrying capacity by 2%, 3.24%, and 3.646 % and decrease in mid-span deflection by 6.54%, 11.67%, and 15.44%. As inferred from FEA output, results of the inclusion of circular openings at shear zone and flexural zone with varying span-to-depth ratio of 1.18, 1.68, 2.18, and 2.68 shows the reduction in load resistance capacity and rises in mid-span deflection. Its load carrying capacity reduced by 2.75%, 5.035%, and 6% and 1.56%, 1.67%, and 6.603% under static loading and 1.1%, 1.38% and 1.733% under cyclic loading, and increase in mid span deflection. Furthermore, change in opening type and location and using steel protective has significant impact on the load resistance capacity and mid-span deflection. In generally, improving RC deep beams with EPS shows significant variation in the structural behavio