Investigation of free-spanned pipeline behavior due to axial forces and local loads

• A test program carried out on pipe members under combined axial and local loads.
• The obtained test results were compared with corresponding FE models and theory.
• The axial load has a significant effect on the pipe behavior against local loading.
• Three different instability modes were characterized on different points of pipe.
• Under the local load, compression strain in the longitudinal direction was created.

This paper presents an experimental study on the deformation behavior of pre-compression free-spanned steel tubular members under lateral loads due to an indenter. The tests were carried out on six similar pipes with an outer diameter of 139.9 mm, a length of 2400 mm and a thickness of 2.55 mm, which are presented and discussed. The strains and deformations were determined in the local load-effected zone, and the effect of different magnitudes of compression pre-loading on the strength of samples against lateral load was investigated.The main advantage of the current investigation compared with those carried out previously and reported in literature is that both the pre-loading axial compression force and local load applied statically by an indenter are included experimentally in the study. From the results of the tests, it can be concluded that pre-loading has a marked effect on the lateral strength and deformation behavior of the pipes. Furthermore, finite element analyses for geometrically identical specimens are presented, and the analytical solutions are compared to the experimental results.