Experimental research on carbon fiber reinforced polymer sheets strengthened fire-damaged reinforced concrete continuous beams

The mechanical properties of Carbon Fiber Reinforced Polymer(CFRP) strengthened fire-damaged concrete continuous beams was tested. Four reinforced concrete T-beams were constructed. One beam was normal temperature control beam, and others were heated under ISO834 curve. One beam was fire damaged control beam, and two beams were strengthened with CFRP sheets. The same test set-up was used to loading tests of four beams. The results showed that bearing capacity, rigidity and ductility of fire-damaged beams were become lower than the normal temperature beam. Ductility and rigidity of beams were dropped sharply, and the way of moment redistribution of beam changed seriously for the influence of fire. The fire-damaged beams had different failure mode compared to the normal temperature beam. External strengthening with CFRP sheets was found to increase bearing capacity and rigidity, but the ductility was dropped further. The way of strengthened position take some influence on moment redistribution of fire-damaged beam. Bearing capacity and rigidity were improved for CFRP strengthened fire damaged continuous beams, but the drop of ductility and moment redistribution after fire should be considered.