Design and Construction of the New "La Unidad" Bridge, Mexico

La Unidad Bridge is located in the south of the Gulf of Mexico, in the state of Campeche, Mexico. The new La Unidad Bridge will replace the existing bridge which was built in the 1980´s and presents several pathologies. The bridge is placed in a very important road parallel to the coast, in the heart of the Mexico´s oil industry, and allows the connection between the “El Carmen” Island and the continent. The new “La Unidad” bridge has a total length of 3285 m, and crosses over the sea with water heights comprised between 4 and 15 m. The bridge has 73 spans of 45 m; the deck is formed by 6 “I” beams of prestressed concrete, with concrete slab. The piers are composed by battered piles formed by steel pipes filled with reinforced concrete. The pile cap is placed directly over the piles. The design and construction of the bridge presented several challenges: the area where the bridge is located is prone to hurricanes and earthquakes, and the soil of the bridge site is relatively soft (formed by sands and clays) and an amplification of the seismic response occurs due to site effects. This paper presents the main aspects of the design and the construction of the New “La Unidad” Bridge. The bridge is now under construction and will be finished at the end of 2018.