John L. Tassoulas

Directional Effects of Shear Combined with Compression on Bridge Elastomeric Bearings

Elastomeric bearings are widely used in bridge supports to accommodate thermal and other movements. The study presented in this paper extends an earlier investigation of two-dimensional bearing performance to three dimensions. Large-deformation rubber hyperelasticity is reviewed and a theoretical model is described with the steel-reinforced bearing subjected to compression in the direction through the thickness followed by shear in various lateral directions, including bridge longitudinal and transverse directions. Computations are carried out using the general-purpose, finite-element analysis computer program, ABAQUS. Conclusions are drawn regarding the effects of shear direction on bearing behavior.

Stability of Ring-Stiffened Tubular Members Under External Pressure

This paper presents results of a rigorous nonlinear finite element technique for the stability analysis of ring-stiffened steel tubes under external pressure. Large deformation, plasticity, as well as residual stresses and imperfections, are taken into account. Both internal and external stiffeners are simulated. A study of various parameters which affect pressure capacity is summarized, along with a comparison with available experimental data.

Hydrostatic effects in tubular member design

This paper summarizes some important results concerning the analysis and design of tubular compliant-tower members. The tubes are subjected to a combination of structural loads and external pressure, which may cause buckling. The paper focuses on the effects of external pressure don the ultimate capacity. Analytical results are compared with experimental data and design equations. The comparison is aimed towards better understanding of pressurized tubular beam-column behavior.