Abstract

Abstract Nowadays , use of castellated steel beams (CSBs) has become very common result of its advantageous implementations in construction of buildings. Castellated steel beams (CSBs) are those members which are fabricated from standard hot rolled steel (HRS) I- sections by cutting along its web in "zigzag" pattern and thereafter rejoining the two halves on one another by welding together to form a castellated beam so that generally depth of section will be increased. This research analyses the experimental results of six specimens of castellated steel beams and compares with control beam (Parent section). The purpose of this study is to investigate the effect of hexagonal hole dimensions on the ultimate strength and stiffens response of castellated steel beam. Also, the effect of number of hole on the behavior of castellated steel beams that have the same span and ratio of expansion was investigated. All specimens of castellated steel beam were fabricated from hot rolled steel section (IPE140) and were expanded to (1.56) times the parent section depth. From the test results, it is observed that best dimension of castellated steel beam was (span length to holes space ratio L/S = 8.0) , (hole depth to Castellated beam depth ratio h/H=0.56) and (hole space to castellated beam depth ratio S/H = 1.03). The ultimate strength of castellated steel beam was increased about (50%) stronger than the original beam.