Steel and glubam hybrid space truss

Abstract

This paper introduces a new type of hybrid truss system composed of glue laminated bamboo (glubam) for web and upper chord members and steel pipes for lower chords. Several experiments of physical and mechanical properties were carried out on the glubam material for structural design and construction according to timber specifications and codes. A full-scale space truss model with different configurations was constructed and tested under gravity loads. Different failure modes, such as buckling of web chords, shear fracture of bolted connecting joints and yield of bottom steel pipes, were discussed. Analyses of the structural behavior under static load are compared with the experimental results, showing a good agreement. The experimental results validate that the space truss system is of excellent load carrying capacity. If yielding of the lower chord steel pipes can be realized, the system can also have a large plastic deformation under the ultimate loading condition. A prototype structure was successfully designed and constructed as a rain-shed canopy of an office building.