Effect of linear transformation on nonlinear behavior of continuous prestressed beams with external FRP cables

In continuous prestressed members, linear transformation of the cable line is an interesting topic that has not yet been adequately addressed. This paper presents a numerical study on the flexural response of two-span continuous externally fiber reinforced polymer (FRP) prestressed concrete beams having various linearly transformed cable profiles, with emphasis on the redistribution of moments. The study is conducted by using a robust computational method that has been validated against experimental tests. The results confirm that the cable shift by linear transformation does not affect the basic performance at all stages of loading up to failure. The secondary moments are shown to vary linearly with the cable shift. The development of moment redistribution over the center support is significantly affected by linear transformation. An upward cable shift leads to a decrease in moment redistribution at ultimate. The results indicate that the effect of linear transformation on moment redistribution is neglected or incorrectly included in various design codes.