Analytical Modeling of Tube‐In‐Tube Structure

Tube‐in‐tube structures are analyzed using a continuum approach in which the two beams are individually modeled by a “tube beamr” that accounts for flexural deformation, shear deformation, and shear‐lag effect. The beams are forced to have equal lateral deflections, and the amount of load carried by each beam is a function of its relative stiffness. The analyses are performed using the Minimum Potential Energy principle, and the results are compared with results of finite element analyses. It is shown that the continuously compatible condition reasonably models tube‐in‐tube structures with as few as five stories.