Experimental Techniques for Lateral Stability Testing of Beams

Abstract

This paper presents experimental setups used in lateral stability tests of beams. The load frame of the setup effectively eliminates the lateral‐translational and torsional restraints at the load application point, while maintaining the vertical orientation of the applied load, despite the lateral deformations and twisting rotations in the specimen. Two different support frames used in the experiments are also presented. The first support frame provides simple support conditions in‐ and out‐of‐plane and the second frame simulates the actual support conditions of an elastomeric bearing pad‐supported bridge girder before construction of the bridge deck. Finally, experimental methods for determining the deformations and longitudinal strains in a beam undergoing lateral torsional buckling are discussed.

Experimental and Measurement Methods for the Small-Scale Model Testing of Lateral and Torsional Stability

“…König and Pauli (1990) utilized steel and water weights as the distributed load mechanism to perform the lateral and torsional buckling experiment in reinforced and prestressed concrete beams. The distributed load mechanism has limitations on space, logistics, and safety, which has rarely been applied in the test (Kalkan and Hurff 2012). Therefore, most of the lateral and torsional buckling experiments have attempted to use a point load mechanism to retain the initial vertical and concentrical position of the applied load without its resistance to the lateral and torsional restraints of the test beam at the loading point.…”

“…Therefore, many studies (i.e., Hansell and Winter 1959;Sant and Bletzacker 1961;Massey 1967;Siev 1960;Revathi and Menon 2007a, b) used roller bearing and ball-and-socket joint mechanisms to minimize the resistance to the lateral and rotational deformations of the test beam at the loading point during the test. Kalkan and Hurff (2012) indicated that the roller bearing mechanism could induce load eccentricity due to some difference between the centroid of the applied load and the beam when the specimen undergoes lateral deformation. Therefore, another load mechanism using a gravity load simulator, which was originally designed by Yarimci et al (1967) to apply a vertical load to a full-scale frame experiment, was used in the lateral and torsional buckling experiments on full-scale steel I-beams (Yura and Phillips 1992;Helwig et al 2005), composite I-beams (Stoddard 1997), and reinforced concrete beams (Kalkan 2014;Hurff and Kahn 2012).…”