“One of the primary structural features of the Tramway are the large concrete counterweights housed in a 40-foot deep pit. While they are unique, the average tramway rider or passerby is not aware of their existence. What they do see - and enjoy - is the result of the careful execution by a conscientious Contractor of a good design.”...“We found Calcedo to be very cooperative. They produced high quality work. The finished product speaks for itself. It is one of the best concrete projects, seen by thousands of people everyday.” - D.Ozerkes, Chief Project Engineer

Concrete & Masonry work on both stations.

Large tension forces on the caissons required heavy reinforcement, which, in turn, dictated that large slump, small aggregate concrete be used. Additional cement was required because concrete was placed underwater in the tremie method and to maintain adequate slump as additional water was added because of the high ambient temperatures that existed during concrete placement.

Manhattan Station: Concrete ground level slab, boarding slabs and beams and four main 40’ high columns, which support the roof and station saddles. Two of these are 41” square composite concrete columns, which are designed to also support a future 32 story building above the station.

Roosevelt Island Station: Two, 2’ thick shear walls serve as the main anchorage for track cables. An 11’-6” diameter concrete bollard, integrally formed as part of the shear wall, protrudes 1’ out from each face of the shear wall. The large uplift force on each wall due to the overturning moment is resisted by splicing tensile reinforcement to a steel base plate which is anchored to rock using pre-stressed rock anchors. 

This is the first such system employed in the United States.

Runs a distance of 3,000 feet. Tower foundation caissons 36” in diameter & up to 50’ long drilled into rock sockets up to 21' deep.

Winner of the Concrete Industry Board Merit Award.

The Manhattan Station of the Tramway won the Exposed Architectural Concrete Award in 1976. 

Owner's Rep
Urban Development Corp.

Architect
Prentice, Chan, Ohlhausen

Designers
Lev Zetlin Associates

Contact
David Ozerkes, C.P.E. for UDC

Location
Roosevelt Island & 
New York, NY