e-mosty 4 2016 Arch Bridges | Page 9

ALMONTE VIADUCT - DESIGN Héctor Beade Pereda, Knight Architects http://www.hectorbeade.com/ Guillermo Capellán, Arenas&Asociados, Santender, SPAIN Fig. 1: Photomontage of the viaduct in the natural environment T SUMMARY The Almonte River arch bridge over the Alcántara Reservoir, which is part of the Madrid-Portuguese Border High Speed Rail (HSR) link, is a challenge for bridge design, engineering and construction. Its 384m main span will make this major project the largest HSR arch in the world and the largest railway bridge in Spain. In order to solve the specific design problems of a HSR crossing with large span and length, a structurally innovative solution was used: the arch, linked to the deck at the crown, has an octagonal section with variable depth and width in its central 210 m, from where it splits itself into two legs with a variable hexagonal section down to the springings. The design combines together structural efficiency, out-of-plane stability (required by HSR horizontal deflection limits), improved response to wind loads (proven by exhaustive wind tunnel tests), transparency, aesthetics and durability. 4/2016