Study on short-term prestress loss of bridge reinforced with large diameter carbon fiber bars

Abstract

At present, the technology of strengthening bridge with prestressed CFRP bars is gradually rising, so it is necessary to study the law of prestress loss. In order to evaluate the short-term prestress loss of prestressed carbon fiber reinforced (CFRP) bars, the prestress loss of CFRP bars used for reinforcement of reinforced concrete beams was studied by combining laboratory tests with practical reinforcement projects. The anchorage loss, concrete elastic compression loss of CFRP bars were obtained by measuring the prestressed loss data of CFRP bars used to strengthen retired old beams and corresponding theoretical calculation. Then, combined with the corresponding loss data of 6 prestressed CFRP bars in the actual strengthening project of Wenzhou Lijing Middle Bridge, the experimental investigation was carried out. The results show that the prestress loss of CFRP bars is between 4%∼8%, and develops rapidly in the early stage, among which the anchorage loss accounts for 45.90%. The anchorage retraction value is about 1.33mm, and the elastic compression loss of concrete is basically negligible.