A new approach for evaluating bond capacity of TRC strengthening

The anchoring of textile reinforced concrete strengthening layers (TRC-strengthening layers) for RC members has been studied with the help of double-lap-compression-tension-tests. Special difficulties are shown which differ from previously known strengthening materials like steel or FRP. For example, the non-linear material behaviour and the cracking of the TRC make it impossible to traditionally measure and analyse the deformation data by means of strain gauges in previously set and constant interval limits. An alternative method for logging and preparing measurement data with the help of the digital photogrammetry is illustrated. The measuring of the crack pattern of the strengthening layer indicates a division of the bond length into an uncracked (state I) and a cracked (state II) range. A first model for ascertaining the load carrying capacity of the bond is presented which takes into account the ranges of state I and II. Further extensions, which are necessary, are pointed out.