The Margaret Hunt Hill Bridge is a bridge in Dallas, Texas, that spans the Trinity River. The bridge is named for Margaret Hunt Hill, an heiress and philanthropist. The bridge was constructed as part of the Trinity River Project. Designed by Santiago Calatrava, it is one of three such bridges planned to be built over the Trinity; the second, the Margaret McDermott Bridge, is completed; the third cancelled. The span parallels the Ronald Kirk Bridge, a walking bridge that was previously the Continental Avenue bridge.
The bridge, which opened in March 2012, is the first of a series of bridges that the office of Santiago Calatrava designed to span the Trinity River in downtown Dallas. The bridge connects Spur 366 (Woodall Rodgers Freeway) in downtown to Singleton Boulevard in West Dallas. Construction on the bridge began in December 2005. The bridge cost $117 million to build. A Dallas Morning News analysis put the project's total cost at $182 million.
On June 26, 2010, the signature 40-story center-support arch was topped with a central curved span, which can now be seen from many miles away in several directions. The arch provides an additional feature to the Downtown Dallas skyline.
In 2012, the bridge received an Outstanding Civil Engineering Achievement Award from the Texas section of the American Society of Civil Engineers. The bridge also received a 2012 European Convention for Constructional Steelwork Award For Steel Bridges.
The cable-stayed bridge supports its 1,870 feet (570 m) length and 1,197 feet (365 m) main span with a steel arch whose peak's height is 400 feet (122 m). An array of twisting cables connect the underside of the arch's curved pylon to the bridge's platform. Fifty-eight (58) white strands descend from the arch and secure themselves along the centerline of the platform. The 16 feet (4.9 m) diameter support is composed of 25 individual segments, secured with 20,000 pounds (9,100 kg) of bolts and additional 450 tons (408,233 kg) of concrete. The bridge provides six lanes for vehicular traffic.
The bridge closely resembles two of three bridges constructed in 2005-2006 above the Autostrada A1 motorway and connecting roads in Reggio Emilia, Italy, that Calatrava had earlier designed. In 2009, the European Convention for Constructional Steelwork gave the two bridges a European Steel Design Award, stating that the structures' original visual effects at different angles give the bridges "the aspect of huge musical instruments."