Timber-concrete-composite (TCC) floors are a successful example of hybrid structural components. TCC are composed of timber and concrete layers connected by a shear connector and are commonly used in practical civil engineering applications. The connection of the two components is usually achieved with mechanical fasteners where relative slip cannot be prevented and the connection cannot be considered rigid. More recently, an adhesively bonded TCC system has been proposed, and has been shown to perform predictably under static short-term loading. One of the main considerations when designing TCC floors is their long-term performance. In the research presented herein, two adhesively bonded TCC beams were exposed to serviceability loads for approximately 4.5 years. During this time the environmental conditions and the deflections were monitored. After having been loaded for 4.5 years, the beams were tested to failure, resulting in findings that long-term loading caused no degradation of the adhesive bond. This research provides input data to develop design guidance for adhesively bonded TCC under long-term loading.
Using bonded fibre-reinforced polymer (FRP) laminates for strengthening wooden structural members has been shown to be an effective and economical method. In this paper, properties of suitable FRP materials, adhesives and two ways of strengthening beams exposed to bending moment are presented. Passive or slack reinforcement is one way of strengthening. The most effective way of such a strengthening was to place reinforcement laminates on both tension and compression side of the beam. However, the FRP material is only partially utilised. The second way is to apply pre-stressing in FRP materials prior to bonding to tension side of flexural members and this way was showed to provide the most effective utilisation of these materials. The state of the art of such a strengthening and various methods are discussed. Increasing the load-bearing capacity, introducing a pre-cambering effect and thus improving serviceability which often governs the design and reducing the amount of needed FRP reinforcement are some of the main advantages. A recent development on how to avoid the requirement for anchoring the laminates at the end of the beams to avoid premature debonding is shown and the advantage of such a system is described.
