A Simple Approach to Static Analysis of Tall Buildings with a Combined Tube-in-tube and Outrigger-belt Truss System Subjected to Lateral Loading

In this paper, an efficient technique is presented for static analysis of tall buildings with combined tube-in-tube and outrigger-belt truss system while considering shear lag effects. In the process of replacing the discrete structure with an elastically equivalent continuous one, the structure is modeled as two parallel cantilevered flexural-shear beams that are constrained at the outrigger-belt truss location by a rotational spring. Based on the principle of minimum total potential energy, simple closed form solutions are derived for stress and displacement distributions. Standard load cases, including uniformly distributed loads, triangularly distributed loads and point loads at top of the structure are considered. Results obtained from the proposed method for a 50-story tall building are compared to those obtained using a standard finite element computer package. The approximate analyses are found to yield reasonable results and give a fairly good indication of actual structure’s response.