Experimental Study on the Lateral Torsional Buckling Behaviour of the Triangular Web Profile Steel Section

Abstract

A triangular web profile (TriWP) section is a structural steel section that is made of two flanges connected to a web plate of triangular profile. Only certain research works have been carried out to study the characteristic, behaviour and the advantages offered by this section compared to the normal flat web (I-beam). An area that is not given full attention is the capability of this section to resist the lateral torsional buckling moment capacity compared to that of the normal flat web. The objectives of this thesis are to study the lateral torsional buckling behaviour of Triangular Web Profile (TriWP) steel section and compare to that of the flat web by experimental and to find the value of Mb, moment buckling resistance for TriWP. The scope of study covered the experimental work and theoretical investigation of triangular web profile steel section subjected to lateral torsional buckling moment resistance. The effect of the shape of the triangular web profile beam compared to that of the flat web beam was also be studied. For the buckling moment resistance, several factors were taken into account such as buckling parameter, torsional index, warping constant and torsional constant. All these factors are related to the second moment of area with respect to minor axis. The lateral torsional buckling test includes 8 specimens (4 flat webs and 4 TriWP). Each specimen was tested in two different sizes which is 200x100x6x3 and 180x75x5x3. Findings from the lateral torsional buckling tests were compared to the manual calculation using BS 5950: Part 1:2000. The lateral torsional buckling test shows that the moment buckling resistance of the triangular web profile steel beam section is better than that of the flat web in smaller size while in bigger size flat web beam has better moment resistance than that of triangular web profile steel beam. The section properties such as width (B), depth (D), thickness of flange (tf) and thickness of web (tw) affect the buckling moment resistance, Mb of the steel section