Behavior of Concrete Deep Beams with High Strength Reinforcement

Abstract

The high performance reinforcement continues to gain wider acceptance in industry practice, for the mechanical properties of these new materials. For decades, methods of design and analysis of concrete members reinforced with normal strength steel have been developed. Recently, reinforcing steel (550 & 550D) with strength higher than conventional steel has become commercially available. The introduction of high strength reinforcing steel can be useful to reduce the quantity of reinforcement required, thereby lessening reinforcement congestion and improving constructability. The paper presents construction and testing of several high strength reinforced concrete deep beams which includes three beams, designed for three different country codes, for each shear span to depth ratio as described and the test data is presented. The beam consists of simple span subjected to two point loads, each span being 0.7 m in length. The shear span to depth ratios ranged from 0.62 to 0.77. Measurements were made during each test inclusive of applied loads and mid span deflections directly from programmed instrument (K.P.T.L.) through load cell and L.V.D.T’s. Cracks were marked and photographed at each initial and final crack. The beams generally failed in shear, exhibiting the behavior of deep beam depending on shear span to depth ratio.