Stiffness and Strength Degradation of Timber Concrete Composite under Fatigue Loading

Abstract

The design of TCC is often associated with Gamma Method to calculate its effective stiffness as its characteristic strength to predict its SLS and ULS behavior. TCC structures used as bridges are subjected to fatigue loadings during service life. Fatigue loadings causes degradation of strength and softening of TCC structure. Such effect produces damaging consequences on the concrete, timber and especially the shear connectors. The effective stiffness degradation of the TCC structure subjected to fatigue loading within SLS and beyond SLS are studied due to scarcity of past researches on the fatigue behavior of TCC structures. This research was carried out by utilizing Malaysian tropical timber (Koompasiamalaccensis) where its strength properties was tested according to ASTM D198 standard procedures. Not much significant changes of its effective stiffness and connection stiffness is observed when subjected to fatigue loadings within SLS but the degradation process occurs at an instantaneous rate when subjected to fatigue loading beyond SLS. The S-N curve, strain profile and post-mortem analysis generated provides a summarization and indicative prediction for the fatigue life behaviour of the designed TCC.