Experimental Testing of Posttensioned Timber Frames under Gravity Loading

Abstract

This paper describes the experimental testing campaign of one-bay and two-bay posttensioned timber frames under gravity loading. Long-span box beams, made of radiata pine laminated veneer lumber, were connected to columns using only the compressive force introduced by posttensioning tendons. The use of tendons with a draped profile resulted in not only semirigid beam-column connections, but also an initial precamber. Both aspects helped to satisfy deflection design limits. The load-deflection behavior of the beams, the increase in posttensioning force during testing, and the connection behavior are evaluated. Of particular interest is the gap opening of the connection, which showed a distinct bilinear moment-rotation behavior. The application of posttensioning tendons to timber frames can more than double the load-carrying capacity at serviceability limit state.