THESIS
2022
1 online resource (xviii, 146 pages) : illustrations (some color)
Abstract
Bamboo has been increasingly popular as a structural material in recent decades, because
of its cost-efficiency, high strength-to-weight ratio, and sustainability. However, currently
there is incomplete understanding on bamboo structural member behavior. This study
initially describes analytically bamboo culm flexure, in terms of failure load and stiffness
loss quantification. It concludes that critical failure mechanisms are tension perpendicular
to the fibers (with potential tension-shear interaction), and longitudinal compression.
Main cause for stiffness loss of bamboo culms in bending is longitudinal splitting, with secondary
cause being non-linear geometric effects at the large deflection stage. In the case
of a single crack at the culm side in particular, main cause of the stiffn...[
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Bamboo has been increasingly popular as a structural material in recent decades, because
of its cost-efficiency, high strength-to-weight ratio, and sustainability. However, currently
there is incomplete understanding on bamboo structural member behavior. This study
initially describes analytically bamboo culm flexure, in terms of failure load and stiffness
loss quantification. It concludes that critical failure mechanisms are tension perpendicular
to the fibers (with potential tension-shear interaction), and longitudinal compression.
Main cause for stiffness loss of bamboo culms in bending is longitudinal splitting, with secondary
cause being non-linear geometric effects at the large deflection stage. In the case
of a single crack at the culm side in particular, main cause of the stiffness loss are torsion-induced
deflections, with secondary cause being shear deformations. Further, shifting the
focus to bolted bamboo connections, the study initially characterizes the bolt embedment
phenomenon under the prism of dimensional analysis. When described in dimensionless
terms (i.e., normalized with bolt diameter and density) the average embedment properties
become a function of a single dimensionless product (the ratio of culm thickness
to bolt diameter) and considerable order emerges. The average dimensionless embedment
properties follow “universal”, species-independent curves. Subsequently, the study
establishes a modified foundation modeling approach to macroscopically capture the embedment
phenomena in bolted bamboo connection numerical simulations. The proposed
approach assumes that foundation zone material properties are the nominal embedment
properties, and rationally defines the dimensions of the foundation zone. Finally, employing
verified bolted connection models in a parametric analysis, the study concludes
that larger bolt clearance and distance between the culms yield lower connection strength
and stiffness, that numerical models adopting minimum (as opposed to average) culm dimensions
yield more realistic results, and, lastly, that, when increasing the bolt diameter,
bolt embedment displacement is more critical for total connection displacement than bolt
deflection.
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