An Experimental Study on the Axial Compressive Behavior of Timber Columns Strengthened by FRP Sheets with Different Wrapping Methods

Abstract

In order to check out the effects of the method how the FRP sheets wrapped on the axial behavior of timber columns confined by CFRP sheet, 6 short columns were confined with CFRP sheets in different wrapped ways, i.e. toroidal, single helix, double helix and cross helix. Another column in the same size was prepared as contrast. The ultimate carrying capacity of the specimens was analyzed as well as the load-displacement curves and strain-stress relationships. The comparison of the ultimate carrying capacity showed significant enhancement when the specimens were confined in any ways, and the way wrapping FRP sheets in the toroidal direction was more efficient than other ways in which the FRP sheets wrapped in the experiment. The analysis of the load-displacement curves indicate that the stiffness of the specimens was improved by the reinforcement with FRP sheets in any ways, however, the improvement of the ultimate carrying capacity and the stiffness was in the cost of the ductility. The comparison of the FRPs train between the specimens with toroidal wrapping method and the helix ones can clearly explain the lower efficiency in the enhancement of ultimate carrying capacity of the specimens with helix wrapping methods.