STRUCTURAL BEHAVIOR OF GROUTED-BAR BAMBOO COLUMN BASES

Abstract

Engineering knowledge of bamboo is surprisingly limited and often focuses on issues associated with 'signature structures' while the behavior of vernacular structures commonly used in the developing world have gone largely unstudied. This document concentrates on understanding the behavior of one of the simplest and most common types of multi- and single-culm foundation connections, termed 'grouted-bar column bases'. These connections consist of a reinforcing bar embedded in a concrete foundation and then grouted into the bamboo column. The objective of this work is to develop an understanding of the complex behavior of these column bases systems in the context of the behavior of a prototype bamboo framing system. Full scale tests of single and four-culm grouted bar column bases were conducted. Additional direct tension pull-out tests of grouted bar connections were also performed. All tests were carried out using Tre Gai (Bambusa Stenostachya) bamboo. Test parameters included the bar size and embedment length of the grouted bar. A basic failure mechanism associating longitudinal splitting of the bamboo culm and slip of the grout plug was identified. Effective properties of the column base suitable for modeling were identified and the relationship between effective flexural properties and fundamental material properties was verified.