Zakim Bridge

Boston, Massachusetts

Hybrid Cable-Stay Bridge

*Home* *Northwest Bridges* *Northeast Bridges* *Midwest Bridges* Indiana Covered Bridges *Suspension Bridges* Truss Bridges Cable-Stay Bridges Arch Bridges *Moveable Bridges* *Cantilever Bridges* Girder Bridge Pontoon Bridge *Piers* *Abutments* *Connections* *References*		Zakim Bridge The Zakim Bridge is a hybrid cable-stay bridge that carries I-93 and US Rt 1 over the Charles River in Boston, Massachusetts. The bridge has both steel and concrete in its cable-stay design. Built as part of the Big Dig and opening in 2003, the bridge's full name is the Leonard P. Zakim Bunker Hill Memorial Bridge. The bridge is currently the widest cable-stay bridge in the world. The main part of the bridge carries four lanes of traffic in both the north and south directions. An additional two northbound lanes are cantilevered outside the cables. Built for a cost of $105,000,000, the bridge was designed by Christian Mean.
	Underside of bridge deck	Cables from tower are spaced evenly to support bridge deck	Base of bridge tower
	Bridge Facts: 1,432 feet in total length 183 feet wide 745 feet length of longest center span Two 295 foot long side spans 40-foot clearance below bridge Two towers are different heights. The North tower is 322 feet tall and the south tower is 295 feet tall. But, both towers are 266 feet above the road deck. The bridge deck has a pitch of up to 5%. Maintained by the Massachusetts Turnpike Authority Bridge is designed to withstand 400 mph and a 7.9 magnitude earthquake Hollow concrete towers were cast in place and have walls which are one to four inches thick The cables are attached to the tower 3" off center due to the weight of the two cantilevered lanes. 116 cables support the bridge 24 cables run from the tower to the median of each sidespan 17 cables run from the top section of the tower to each side of the center span bridge deck Longest cable is 500 feet long Each cable is made up of 14 to 73 strands depending on its distance from the tower The 3 cables farthest from the tower in the center span are anchored to spline beams that go underneath the bridge deck		Looking at side of south tower Angle in tower design
	Cables are attached to multiples places on tower, not just at top of tower	Top of tower	South tower
	Connection of support cables to bridge deck	Detailed view of cable connection to bridge deck	Connection of support cables to tower
		Cables attached to tower 3" off center to allow for weight of cantilevered lanes
	All photos by Brenda Campbell Teacher at Centerville High School, Centerville, Indiana.