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mhh bridge

mhhThe first steel bridge across the Trinity River is designed by internationally renowned Spanish artist, architect and engineer Santiago Calatrava. The Margaret Hunt Hill Bridge is Calatrava's first vehicular bridge to be built in the United States. The world-class bridge is being constructed to seamlessly connect Singleton Boulevard in West Dallas across the Trinity River to Woodall Rodgers (Spur 366) in downtown Dallas and points beyond.

mhhAlready an icon of Dallas, the gleaming 400-foot white arch, consisting of 25 steel segments, anchors the cable-stayed portion of the bridge with 58 cables ranging in size from four to eight inches in diameter. Each cable attached to the arch is secured back down into the center spine of the bridge bed itself, thus holding itself in suspension. Spring 2011, the cables were completely installed on the bridge. The false work (temporary supports under the suspension section) was removed in the summer, letting the cables rest. The next step is completion of the roadway approaches on both sides of the bridge. Photography by Jeremy Dickie


What makes the Margaret Hunt Hill Bridge unique?
The Margaret Hunt Hill Bridge transforms the Downtown Dallas skyline and is recognizable as the city's newest icon, demarcating the Trinity River Corridor beneath it. The bridge is also Santiago Calatrava's first vehicular bridge in the United States.

What does the bridge connect?
The Margaret Hunt Hill Bridge connects Downtown Dallas to West Dallas over the Trinity River. Woodall Rodgers Freeway and Singleton Boulevard are the two roadways connected by the bridge.

Why is it named Margaret Hunt Hill?
Margaret Hunt Hill was a renowned civic leader and first-born daughter of Texas oil magnate, H.L. Hunt, Jr. In 2005, the Hunt Petroleum Company of Dallas made a generous contribution to The Trinity Trust Foundation for the first Calatrava signature bridge. Her legacy has brought together more than 17 diverse organizations and thousands of volunteers who support the work of transforming and revitalizing the land in and around the Trinity River. These leaders, thinkers and doers have helped the Margaret Hunt Hill Bridge become a reality.

Who is the designer of the bridge?
Santiago Calatrava. Born in Valencia, Spain, Calatrava is an internationally renowned architect, engineer, artist and sculptor who has created more than 42 bridges around the globe.

How was Mr. Calatrava selected?
The first master plan had been implemented in the late 1990s. Halff & Associates had been involved in this plan and suggested Santiago Calatrava because they had seen his work and his bridges in Spain. In the late 1990s (1999) Mayor Ron Kirk had asked Margaret McDermott if she could make a donation to hire Calatrava to design a bridge, and she agreed.

When did construction begin?
Construction began on June 14, 2007.

When will construction be completed?
The bridge will be completed in March 2012.

What's the cost of the project?
The construction contract for the signature span and approaches inside the levees was awarded for $69.7 million. The construction contract for the approach spans outside the levee was awarded for $50 million.

Will there be a celebration for the opening of the bridge?
Yes, the Margaret Hunt Hill Bridge Celebration will take place March 2-4, 2012, on the bridge itself. This will be the only time that citizens and guests can walk, run or party on the bridge before it's open to vehicular traffic. More information can be found at

How long is the bridge in miles?
It is .366 miles.

How long is the entire bridge in feet from levee to levee?
It's 1,870 ft.

How wide is the bridge?
The bridge is 120 feet wide.

How many lanes does the bridge have?
There are six lanes, three on each side.

How tall is the center arch from the deck to the top?
It's 400 feet, about 40-stories tall or as tall as the W Hotel in Downtown Dallas.

How many cables are on the bridge?
There are 58 cables.

Is each cable the same diameter?
They vary in size.

If all the cables on the bridge were placed end to end, how far would they stretch?
It would stretch 5 miles.

How long is the center signature span?
It is 1,200 feet long, 600 feet on each side.

Is this a suspension bridge, or is this a cable-stayed bridge? What is the difference?
It is a cable-stayed bridge because the cables are not connected to two main towers, but connected to the arch and the center of the roadbed.

What river does the bridge cross?
It crosses the Trinity River, the longest river that begins and ends in Texas.

How many vehicles per day are expected to cross the bridge?
According to North Texas Council of Governments, an estimated 42,000 vehicles are expected to cross the Margaret Hunt Hill Bridge per day.

How many vehicles will it remove from the Mixmaster?
According to TXDOT, the agency estimates that the bridge will remove 10,000 vehicles per day from the Mixmaster.

What is the name of the bridge that is closest to the Margaret Hunt Hill Bridge, and what is going to happen to it once the new bridge is open?
Continental Avenue Bridge. Once the Margaret Hunt Hill Bridge is open, then the Continental Avenue Bridge will be closed and transformed into a pedestrian bridge and plaza for the community, further connecting West Dallas and the Design District.

How deep would you have to dig to reach the bottom of the center columns?
It's about 40 ft.

Why is there a red light at the top of the arch?
It is a regulation light to make it visible to airplanes and helicopters, especially at night.

What can you tell me about the lights that illuminate the bridge at sundown?
More than 200 lights illuminate the 400-foot arch, the 58 cables, the roadbed, and the underside of the bridge, The lights bring attention to the sculptural bridge and the Trinity River at night.

Where was the steel made, and how did it get to Texas?
The steel was fabricated in Italy and transported to Houston, Texas, via large cargo ships.

How did the steel manufacturer ensure that the pieces would all fit after they were made?
The Italian steel manufacturer, Cimolai, first assembled the arch together on the ground in Italy as each piece was made to ensure an exact fit and weight combination.

How many tons of steel were used in the bridge? In the arch?
According to Texas Department of Transportation, 11,643,674 lbs. of structural steel was used for the entire bridge. The arch by itself is 3,083,118 lbs.

On average, how much do the cylinders weigh?
If you average 90,000 lbs. per cylinder x 25, that's 2,250,000 lbs. of steel just in the arch because the cylinders weigh between 80,000 and 110,000 lbs. each.

How many pieces of steel fit on each transport truck that brought them to town?
There was one truck that hauled the center arch alone because of its massive size. It took 25 trips with each trip averaging two days and the same for the box girders, taking even more trips and days to get all of them to Dallas.

How many steps are inside the arch to the top?
There are 1,020 steps.

What are the components of this cable-stayed bridge?
• 58 cables attached to the center of the deck
• Arch pylon is comprised of 25 segments
• Type C Floor Beam 1 at arch pylon
• Type B Floor Beam 116 pieces
• Type B Floor Beam Strut 116 pieces
• Support Bracket 2 pieces
• Central Box Girder 30 segments
• Exterior Box Girder 2 at 60 segments each

What equipment was used to build the bridge?
Cranes were used for setting metal/wood forms; a drill rig for drill shafts and temporary drill shafts; bulldozers and front loaders for building pads and other elements of the preconstruction were used. For the steel shipment and placement, a special Manitowoc 1,000-ton crane was in the flood plain. This type of crane is extremely expensive to operate, and the crane operator usually travels from job to job with the crane.

Who built the bridge? Who was the main contractor? Subcontractors?
Texas Department of Transportation has been responsible for building the bridge and awarded the contract to Williams Brothers Construction Company, Inc. as the main contractor. J. D. Abrams, L.P. has built the Woodall Rodgers Freeway extension connecting the bridge on the east side and the west connection onto Singleton. Huitt- Zollars, Inc. was the engineering/architectural firm.

Other subcontractors:
Mike Albert, Inc.
Ark Contracting Services, LLC
ATS Drilling
AR Daniel Services
Azteca Cadit Company, Inc.
Choctaw Erectors, Inc.
Construzioni CIMOLAI Armando S.p.A.
Cosme SRL
Dallas Lite & Barricade Inc.
Dynamic Vision
Fortson Contracting, Inc.
Great Western Erectors, LLC
Highway Pavement Specialties
Highway Technologies, L.P.
Hirschfeld Steel Group
Indus Construction, L.P.
Layfield Construction
L & E Hart Enterprises, Inc.
Lina T. Ramey and Associates (surveyors)
MICA Corporation
Craig Olden, Inc.
Odum Services, L.P.
Primate Construction, Inc.
Reynold's Asphalt and Construction Co.
RG Painting (Raymond Painting, Inc.)
Scott Derr Painting
Star Operations, Inc.
Stomper Demolition Co.
Stripe-A-Zone, Inc.
Texas Environmental Management SA, Inc.
TexOp Construction
Trevcon, Inc.
O. Trevino (FKA: J.L. Steel, Inc.)
VFC, Inc.
Weir Bros.

Other groups and individuals involved in the Margaret Hunt Hill Bridge:

The City of Dallas has been involved in the overall management of the project. The City of Dallas will own the bridge once completed.

The Trinity Trust Foundation – responsible for raising private dollars so that the bridge could be designed by Santiago Calatrava.

Trinity Commons Foundation – responsible for advocating/lobbying for federal funds for The Trinity project. Both The Trinity Trust and Trinity Commons Foundation are responsible for the Margaret Hunt Hill Bridge Celebration, March 2-4, 2012.

North Central Texas Council of Governments

Santiago Calatrava – internationally renowned architect who designed the Margaret Hunt Hill Bridge

U.S. Senator Kay Bailey Hutchison -- Dallas applauds the years of devoted effort by US Senator Kay Bailey Hutchison on behalf of The Trinity project, including securing needed funds making it possible to build the Margaret Hunt Hill Bridge.

U.S. Representative Eddie Bernice Johnson – She has worked tirelessly for many years to support The Trinity project and continues to be one of the Trinity's strongest champions in Washington. She has helped secure hundreds of millions in federal funds for the project, including funding for the Trinity River bridges.

U.S. Congressman Pete Sessions – He has been a strong supporter of The Trinity project since the Project's inception. He has worked very hard over the years to ensure that the Project moves forward in a responsible, cost effective way. He continues to provide leadership on behalf of the project.

Dallas City Manager Mary Suhm – She has been a catalyst for every aspect of the Trinity Project for two decades, spearheading the combined efforts of the Texas Department of Transportation, the architects, the engineers, and the construction workers on the Margaret Hunt Hill Bridge.

Three Former Dallas Mayors who are the Honorary Chairs of the Margaret Hunt Hill Bridge Celebration -- The Honorable Ron Kirk, The Honorable Laura Miller and The Honorable Tom Leppert—all of whom worked on this project.

Who owns the bridge after it's built?
The City of Dallas owns the bridge.

Additional construction numbers:
Arch span column (concrete portion) = 30 feet
Each arch span column features 250 cubic yards of concrete
Each cubic yard = 3600 pounds
Total concrete per arch span column = 450 tons
Diameter of column = approximately 16 feet
Steel piece diameter = 14 feet 7 inches
Number of bolts per arch span column = at least 72
Bolt length = 16 feet each
Bolt weight (total) = 20,000 pounds