Improving the behaviour of plate girders via modification with additional FRP layers

Ensuring sufficient resistance of structures of buildings and bridges is one of the main directions for minimisation of damage and losses due to limited lifespan. Traditionally used reinforced concrete and steel structures are well known and reliable materials, but for both of them the corrosion of steel elements and the increased loading requirements are demanding permanently increased maintenance costs. The problem is getting even worse from the point of view of enormous amount of already significantly old infrastructure elements for all developed countries.

Typical examples of such vulnerable and important structural elements, widely used for construction of bridges and other structures requiring significant open spaces and corresponding longer spans are the plate girders. The presented research is aiming to investigate the opportunity lighter and stronger than steel FRP materials to be used in addition to the traditional steel elements to form innovative stronger and more durable hybrid structures.

The investigation is experimental and is incorporating the development of scaled models of plate girders with additional CFRP and GFRP layers acting simultaneously as reliable protection against corrosion and increasing the load bearing capacity.

The experiments are planned as displacement controlled, automatically following previously defined quasi-static regime and including measuring of the applied force, the deflections, the strains in range of indicative points and visual monitoring of process of developing of damages including delamination and tearing of FRP layers.

Obtained results for a range of samples will be analysed in aspect of ultimate capacity, process and mode of destruction and estimation of the energy absorption capabilities. They will be analysed and compared with other similar investigations and appropriate conclusions will be offered.