A long term laboratory investigation on two six-meter-span timber composite beams was started from March 2012 at the University of Technology Sydney. These timber composites were made of laminated veneer lumber (LVL). The web and the flanges of the composite timber section were connected using screw-gluing technique. The specimens have been under sustained loads of (2.1kPa) and the environmental conditions was cyclically alternated between normal and very humid conditions whilst the temperature remained quasi constant (22 °C) –typical cycle duration was 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 were continuously monitored. The paper presents the results and observations of the long-term test to-date and the test is continuing.
The objectives and scope of this study are to conduct long-term experimental test on timber-concrete composite beams, analyse the results to determine the creep coefficient of the composite system and compare the experimental results with the analytical solutions in accordance with Eurocode 5, in which the effective modulus method is used to account the effect of creep. To achieve the aforementioned objectives, a long-term laboratory investigation was started in August 2010 on four 5.8m span TCC beams with four different connector types. The specimens have been under sustained loads of 1.7kPa and subjected to a cyclic humidity conditions whilst the temperature remains quasi constant (22 °C). During the test, the mid-span deflection, moisture content of the timber beams and relative humidity of the air are continuously monitored. The long-term test is still continuing, two TCC beams were unloaded and tested to failure after 550 days, while the other two TCC beams are still being monitored and this report included experimental results up to the first 1400 days only. The long-term investigation on the two timber only composite floor beams commenced on March 2013 and the results are reported for the first 800 days from their commencement.