Long-term experimental test on timber-concrete composite beams

A long term laboratory investigation started in August 2010 at the University of Technology, Sydney. The test is conducted on four 5.8m span LVL-concrete composite beams (referred to as TCC beams here onwards) beams with four different connector types: Type 17 screws, four and six notches with coach screw and SFS screws. The materials used are Laminated Veneer Lumber (LVL) for the beams and 32 MPa concrete for the flanges. The investigation is still continuing. The specimens have been under sustained loads of (1.7kPa) whilst the environmental conditions have been cyclically alternated between normal and very humid conditions whilst the temperature remains quasi constant (22 °C) - typical cycle duration is six to eight weeks. With regard to EC 5, the environmental conditions can be classified as service class 3 where the relative humidity of the air exceeds 85% and the moisture content of the timber samples reaches 20%. During the test, the mid-span deflection, moisture content of the timber beams and relative humidity of the air are continuously monitored. The paper presents the results and observations of the long-term test to date. It will discuss numerical models found in the literature and examine their fitness to predict the long-term behavioural responses of the specimens. Copyright © (2012) by WCTE 2012 Committee.