Cable Trusses Subjected to Earthquakes

Earthquake responses of cable trusses with top cable curved up and bottom cable curved down and diagonal web members are the main subject of this study. Such trusses have special features as diagonals come in and out of action during vibration. An outline of nonlinear analysis of static and dynamic problems of elastic cable trusses were presented and results checked with published examples. For limiting the degrees-of-freedom, only plane trusses are studied herein with masses lumped at the joints. Analysis of an example truss is presented. The truss is pretensioned so that it will have very small deflection under dead load and there will be sufficient tension in the lower cable to stabilize the structure when line load occupies whole or half the span. Deflections and member forces of the example truss subjected to vertical and horizontal (north-south) El Centro earthquake are given.