LATERAL PRESTRESSING OF RC COLUMNS WITH FRP JACKETS

摘要

This paper presents the results from experiments on a new strengthening technique for concrete columns that uses expansive materials to apply lateral pre-tensioning. The level of pre-tensioning is controlled by using different amounts of expansive agent. The technique aims to enhance the capacity and ductility of columns as well as achieve better utilisation of the confining FRP material. It is shown that jacketing columns by pre-tensioned FRP materials can increase the load bearing capacity up to 30% compared with conventional wrapping and up to more than 2 times compared with unconfined concrete. However, the most important effect of pre-tensioning is a delay in the initiation of the fracturing process of the concrete through cracking. The paper presents details of experimental work undertaken with different confining materials (CFRP and GFRP) but having the same ultimate jacket strength.