GRD Journals- Global Research and Development Journal for Engineering | Volume 1 | Issue 8 | July 2016 ISSN: 2455-5703
Experimental Study on Post Buckling Behaviour of Steel Plate Girder Rohit V. Khobaragade Department of Civil Engineering Kavikulguru Institute Of Technology and science,Ramtek441106, Nagpur University
P. D. Ramteke Department of Civil Engineering Kavikulguru Institute Of Technology and science,Ramtek441106, Nagpur University
Abstract This paper describes three tests on small scale, transversely stiffened plate girder. The objective of the test was to observe collapse mechanism and to study post buckling behavior i.e.in particular to investigate the behavior of the transverse web stiffeners. A problem was selected to choose the dimensions and loads of the plate girder and design can be solved according to clauses of Indian Standers 800-2007. Model analysis technique was used to reduce the dimensions and loads of actual structure. Accordingly three small scale plate girder models were constructed with varying number of stiffeners and with constant dimensions of web, flange and stiffeners. The main objective of this experimental study was to study post buckling behavior. The observation given should facilitate future development of improved method of stiffeners. Keywords- Longitudinal deflection, lateral deflection, web buckling, web crippling, tension field stress
I. INTRODUCTION Plate girder is basically an Iâ&#x20AC;&#x201C;shape beam constructed from plates using riveting or welding. It is a deep flexural member used to carry loads that cannot be economically carried by rolled beams. Generally rolled beams are used for general structure but in situation where the load is heavier and span is large the plate girder is generally used. The designer has choice to choose component of convenient sizes therefore plate girder offer unique flexibility in fabrication and the cross- section can be uniform or non-uniform along the section. Plate girder provides maximum flexibility and economy in the design of plate girder. For the short span (< 10 m) plate girder are uneconomical due to higher connection cost and hence rolled I-section is generally preferred but the span (> 10 m) and up to the span of 35 m plate girder are economical and used in the railway bridges of span 15 to 40 m and in highway bridges of span 24 to 46 m and also used in building when it is required to support heavy concentrated load exlarge hall. Plate girder are generally composed of compact flanges, slender webs, transverse and longitudinal stiffeners. For efficiency, most plate-girder cross sections are built geometrically similar to wide-flange steel beams, i.e., with top and bottom flanges to resist normal stresses associated with bending moment and a deep web plate to resist resulting shearing forces. The transverse stiffeners are provided vertically and closed to support to increase the bearing resistance and to improve shear capacity. The longitudinal stiffeners provided in horizontal direction to increases the buckling resistance of the web against bending. Rode [1916] developed the first physical explanation for very high shearing capacities of slender plate girder webs. Wagner [1931] developed the theory of uniform diagonal tension field. Basler [1950] was the first to develop a successful plate girder model for tension field action of the type used in civil engineering structure. Wilson [1986] was the first to discover the post buckling behavior of plate girder web panels by studying the slender aluminium shear panels with rigid boundary elements utilized in aircraft structures. Galmbos [1998] developed many theories for the ultimate shear capacity of plate girder. Porter et al introduced Cardiff model in which collapse of girders was related with the emergence of plastic hinges in flanges. Cardiff model was later adopted into the British Standards. Hoglund proposed a simplified rotating stress field theory to simulate stiffened and unstiffened web plates and his theory later introduced into the Eurocode 3.
II. DESIGN OF PLATE GIRDER A simply supported welded plate girder having span of 30 m and udl of 30 kN/m and two concentrated load of 150 kN. Each acting at 10 m from both end and having load factor of 1.5, yield stress f y =250 MPa.is selected and design can be solved according to clauses of IS 800-2007. The values obtained from selected problem given below1) Maximum bending moment =7987.5 kN/m 2) Maximum shear force= 990 kN 3) Required flange area = 21965 mm2 4) Assume flange width = 550 mm. 5) Thickness of flange = 40 mm. 6) Section of the flange = 550Ă&#x2014;40 mm. 7) Total depth of girder =1680 mm 8) Assume thickness of web = 20 mm .
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