Recent Developments in Concrete Arch Bridges

Arenas & Asociados has a special relationship with concrete arch bridges since Professor Arenas founded the company in 1999. This abstract tries to synthetize the evolution of concrete performance and arch bridge design and construction techniques, through the real example of three recent structures. The first of them is the Third Millennium Bridge over River Ebro (Zaragoza, Spain). This concrete tied arch bridge is the largest of its type built to date, with a main span of 216 m. Its construction required the use of innovative techniques, among others, the development of white color high-strength self-compacting concrete. This concrete reached actual compression strengths of 85 MPa, higher than the 75 MPa required for the arch and 60 MPa for the deck, due to the need of prestressing at short concrete ages during construction, in order to reduce execution times. Las Llamas half-through Arch Bridge (Santander, Spain) continues this saga. The arch is 102 m long, and it is built in white high-strength self-compacting concrete C-60. The deck's main girder hangs from the arch in its central 60 m, with two side spans of 21 m. Intermediate arch, box girder and hangers form the main longitudinal structure, while in transversal direction it is formed by 2.4 x 9 m inclined precast cantilever slabs and a top concrete slab transversally prestressed. Finally, this evolution on the study and performance of high-strength concrete comes to an end with the impressive Almonte Viaduct (Caceres, Spain). This high-speed rail concrete arch bridge, flies over River Almonte with a 384 m span. The arch has been constructed using 80 MPa self-compacting concrete, especially composed for the high setting temperatures of this project (UltravalSR concrete reaches 40 MPa in 12 h and 90 MPa in 28 days, and it was mixed with fly ash and river sand as well as admixture Glenium TC1425).