Load deformation characteristics of normal and fiber reinforced concrete columns

ABSTRACT: Although a lot of works has been done in the field of steel fiber reinforced concrete beam-column joints, slab-column connections, etc. under lateral cyclic loading which represents earthquake and wind forces, a few studies exist that peruse monotonic lateral loading. It is important to determine deformation characteristics of structural elements under monotonic lateral loads in building; meanwhile they are reinforced with both steel bars and hooked end steel fibers. This thesis tries to find some answers to prediction of effects of steel fibers in deflection of reinforced concrete columns. Therefore, columns have been designed both with normal and fiber reinforced concrete, then lateral displacement versus load behavior has been observed. A test setup was designed and built based on similar tests conditions. Two hydraulic jacks were used to apply lateral and vertical loads simultaneously. The axial load that was applied was almost 300 kN and the lateral load was increasing monotonically. The loading was performed manually and data was recorded by a digital data logger using measurement devices such as LVDTs, strain gauges, and load cells. As was expected, the test results showed a considerable increase in displacement of fibrous columns in comparison to non-fibrous one, which demonstrated clearly that presence of hooked-end steel fibers increase the displacement capacity of reinforced concrete columns under axial and lateral loads as was expected from all other structural members containing the steel fibers. Steel fibers also reduce cracks in columns surface, and prevent cracks from getting wide during the loading and until the crushing. Keywords: Concrete columns, deformation characteristics, lateral loading, steel fibers. …………………………………………………………………………………………………………………………………………………………………………………………………………