Analysis of reinforced concrete beams strengthened by external unbonded bars

Inelastic behaviour of PSC beams with unbonded external tendons

“…In contrast, for an externally prestressed concrete beam, it is necessary to formulate the global deformation compatibility between the anchorages and/or deviators of tendons for the calculation of prestressing force along the span (Ariyawardena and Ghali, 2002;Cairns and Rafeeqi, 2002;Wu and Lu, 2003;Wu et al, 2001) because the external tendons contact the concrete member only at deviators and anchorages (see Figure 1). In advance, the external tendons, which have a rectilinear profile between the deviators, are free to move from the concrete section.…”

“…Furthermore, frequent application of heavyweight vehicles, the abundance of which has rapidly increased in line with economic development, accelerates the decrease of the remaining service life in bridges. Many bridges designed in the past according to previous design codes (Cairns and Rafeeqi, 2002;Harajli et al, 1999) accordingly require upgrading through proper strengthening techniques so as to cope with changes in the design conditions and, in advance, recover their service life.…”

“…Even though these differences may not be critical at the service load stage, they can have a considerable effect at the ultimate load stage. Accordingly, most experimental studies (Allouche et al, 1999;Aparicio et al, 2002;Cairns and Rafeeqi, 2002;Rao, 1996;Tan and Ng, 1997;Virlogeux, 1990) have concentrated on beam structures with different cable profiles in the investigation of the structural behaviour of the externally prestressed flexural member and the effects of the external cable.…”