Experimental study for strengthening octagonal castellated steel beams using circular and octagonal ring stiffeners

Abstract

Castellated beams made by cutting web of hot rolled steel I-section in particular zigzag pattern and recollecting the two parts by welding, to form a castellated beam with hexagonal openings, or more increasing of section depth by placing expansion plates between these parts to fabricate castellated beam with octagonal openings. The main advantage of fabrication this type of beam is increasing section depth, which leads to improve its behavior compared with original beam. So as to use the castellated beams with expansion plates into its best advantages, the failure modes due to web opening need to be avoided. This paper aims to provide added strength of castellated beams with expansion plates by using two types of stiffeners (circular and octagonal ring) around octagonal web opening. This strengthening technique was suggested to reinforce web portion and avoid failure due to web-post buckling. Standard (IPE140) were chosen as a parent section for fabricating four specimens as well as original beam. The important observation through this study is that using ring stiffener leads to have significant effect on ultimate strength. In case of using circular ring stiffeners, the ultimate strength was increased up to (188%) compare with original beam. Whereas the increment in ultimate load at using octagonal ring stiffeners was reach to about (77.6%). Consequent, using circular ring stiffeners to reinforced this type of beams was more efficient than using octagonal ring stiffeners. It is worthwhile to mention that it can be used (37%) as additional steel material (Expansion plates and ring stiffeners) for increasing the load capacity of castellated beams up to (288%) relative to original beam.

The magnitude of stress concentration of I-beam with web opening because of lateral-torsional buckling effects

“…Besides that, square or rectangular steel tubes are used in wide flange shapes and a cover plate at the bottom of the steel section is added. Another utilization adopted since the past year is tapered beams, where the beam depth varies throughout the span depending on the function of each structural member (Sayyad and Shaikh, 2020; Ponsorn and Phuvoravan, 2020; Elaiwi et al , 2019; Al-Thabhawee and Mohammed, 2019). Since 1950’s, the strength nature of castellated beams become more beneficial in terms of structural design (Estrada et al , 2006).…”

Numerical Analysis of CASTALLED Beam Using Ansys

“…Due to its beneficial construction purposes, such as their light weight, low cost, relatively high reaction, and ability to be quickly assembled on the construction site, castellated beam use has become increasingly widespread. [10][11][12] These applications make use of the castellated beams' improved strength and affordability. In addition, there are many castellated beam failure modes, including the Vierendeel collapse method, web post buckling, flexural failure, lateral torsional buckling, and shear failure.…”