By Penelope Smith and Alan Vara The New NY Bridge Project: A Look at the Structural and Economic Aspects of the Tappan Zee Bridge and its Replacement By Penelope Smith and Alan Vara

The Old Tappan Zee Bridge Length: 3.0328 mi (4.8808 km) Height: 138 ft Finished in 1955 Connects South Nyack, Rockland County, New York and Tarrytown, Westchester County, New York in the Lower Hudson Valley Cantilever Bridge (one fixed one, one “free” end)

Why replace the Old Bridge? The Tappan Zee has become somewhat notorious for traffic and accidents. It is very clearly a safety hazard with the lack of wide lanes, and traffic does not aid when it comes to this. Also, because of the bridge being worn down over the years, it has become less expensive to actually build a new bridge than simply keep repairing it.

So what’s new about the Bridge’s Replacement? It is a cable-stayed bridge (more cost effective than suspension bridge) Seismic isolation barriers (prevent natural disasters such as hurricanes or earthquakes from demolishing the bridge) Wider lanes (12 ft vs. 11ft), and more lanes than the original Suicide prevention measures (unclimbable fences, stainless steel netting below viewing locations along the bridge) Emergency turn around lanes for drivers Mass Transit Lanes for buses, and a shared path for cyclists and pedestrians

How the New Bridge is being built Cement foundation -> placing steel pipes to bedrock under the water and pouring in cement to ensure full support and to prevent pipe contamination Four towers -> built in the same way, steel and metal rods with cement reinforcement (several support structures) Cable wires -> metal cables connected to the towers help to hold up the road

Pictures at the Construction Site taken by Students at the Field Trip

Bibliography http://www.newnybridge.com/ http://www.hdrinc.com/portfolio/new-ny-bridge-design-build-tappan-zee- hudson-river-crossing http://newyork.cbslocal.com/2014/03/28/new-tappan-zee-bridge-to-have- suicide-prevention-measures-in-place/ https://en.wikipedia.org/wiki/Tappan_Zee_Bridge The Presentation @ HSMSE