Rational Use of Terminal Anchorages in Portland Cement Concrete Pavement

Abstract

Portland cement concrete (PCC) pavements have long been thought to expand and push bridge structures, with bridge damage resulting. To protect bridge structures from expanding PCC pavements, three terminal systems are currently used in Texas: anchor lug (AL), wide flange (WF), and expansion joint (EJ). Even though the Texas Department of Transportation uses all three systems in continuously reinforced concrete pavement (CRCP), the effectiveness of these three systems has not been fully evaluated. The parameters affecting CRCP movement near bridge terminal areas are investigated: whether thermal expansion of CRCP is damaging bridge structures, and if so, which terminal type is most cost-effective. Extensive field evaluations reveal that slab movement at the end of the CRCP are substantially restrained by subbase friction. Slab length from the end of the CRCP that significantly contributes to slab movement is limited to about 200 ft (60.96 m) for the CRCP system with asphalt base typically used in Texas. Slab movement rates due to seasonal temperature variations are larger than daily slab movement rates. The movement at the end of the CRCP can be accommodated by a simple EJ with subbase friction, which can be achieved with typical asphalt-stabilized base. The use of an AL system is not needed to restrain concrete slab movement. The benefits of WF and AL systems are doubtful when one considers that their cost is higher than that of the simpler EJ system.