The Triborough Bridge Project is a three-branched waterway crossing that connects Manhattan, the Bronx, and Queens at a junction of the East River and the Harlem River in New York City. The complex structure includes a suspension bridge from Wards Island to Queens, a vertical lift span from Randall's Island to Manhattan, a fixed span (designed to be convertible to a lift span) across the Bronx Kills, viaducts, and an innovative three-legged roadway interchange.
Bridges
Built between 1819 and 1826, the Menai Bridge was the major structure on Britain's strategically important Holyhead Road connecting London with Holyhead and by sea to Ireland. Designed by Thomas Telford, the bridge's main span was 579 feet from tower to tower, the longest that had ever been attempted at this time. He used four sets wrought-iron eyebars to suspend the deck. These were made by William Hazledine at his Upton forge near Shrewsbury. Each bar was carefully tested in his Coleham shops before being pinned together and lifted into place.
The design of the Sydney Harbour Bridge closely resembles the Hell Gate Bridge over the East River in New York City, conceived in 1916 by noted engineer Gustav Lindenthal and his chief assistant, O.H. Ammann.
The Starrucca Viaduct of the Erie Railroad Company crosses Starrucca Creek in Lanesboro, Pennsylvania. It is one of the oldest and one of the longest railroad bridges in Pennsylvania. Its 18 slender, semicircular stone arches each span 50 feet and the structure rises 110 feet above the creek.
Three rivers - the Allegheny, Monongahela, and Ohio - join in Pittsburgh, making the city a natural site for the building of bridges. But the Smithfield Street Bridge stands apart from other Pittsburgh bridges for several reasons: it replaced structures by two well-known bridge engineers, Lewis Wernwag and John A. Roebling; it was the first use in America of the lenticular - or lens-shaped - truss design; and it was one of the first major bridges in the U.S. built primarily with steel.
Sewall's Bridge is a singular example of an era when wooden trestle bridges carried highway traffic across New England waterways. It is the earliest pile-trestle bridge for which an authentic construction record exists, and the oldest for which builder's drawings survive. Spanning the York River, it was named for Major Samuel Sewall, Jr., the civil engineer who designed and constructed it.
The Second Street Bridge is a simply ornamented, wrought-iron structure. It is 18 feet wide and spans 225 feet over the Kalamazoo River. It was built to replace a dilapidated wooden bridge that had served the area for nearly 50 years.
The bridge is anchored to fieldstone abutments on each shore, and the deck is composed of wood beams. Iron lattice work provides structural stability and iron finials on the end posts provide aesthetic appeal. It includes a wooden pedestrian walkway.
The Salginatobel Bridge, spanning the Salgina Valley ravine, is the earliest surviving three-hinged, hollow box arch bridge designed by Robert Maillart.
The third bridge built on the same site to carry railroad tracks across the Susquehanna River just north of Harrisburg, Pennsylvania, the Rockville Stone Arch Bridge, at 3,820 feet long and 52 feet wide, is believed to be the longest and widest stone-arch railroad bridge in the world. A central link in rail travel between New York City and Pittsburgh, the Rockville Stone Arch Bridge accommodates four lines of railroad tracks, today serving both the Norfolk Southern and Amtrak lines.
A bridge across the Hudson at or near Poughkeepsie was planned starting in the early 1870s to primarily carry coal from the coalfields of northeastern Pennsylvania to New England. At the time there were no bridges between Albany and New York Harbor. Horatio Allen, soon to be President of the…
Read MoreThe bridge is immense, not only in length and weight but in width. At 67 feet wide, it can accommodate two sets of railway tracks, two sets of streetcar tracks and two roadways.
It took three tries and cost 89 lives, but the city of Quebec was determined to compete with provincial rival…
Read MoreWhen opened in 1909, the Queensboro Bridge had the two longest steel cantilever spans in the world - 1,182 feet from Manhattan to Blackwell's Island and 984 feet from Blackwell's Island to Queens. These would remain the world's longest cantilever spans until the completion of the Quebec Bridge…
Read MoreAlvord Lake Bridge, along with many of Ernest Ransome's reinforced concrete buildings, survived the 1906 San Francisco earthquake and several subsequent tremblers with no damage. Built in 1889 by Ernest L Ransome of New York, this reinforced concrete arch bridge in San Francisco's Golden Gate…
Read MoreThe third bridge built on the same site to carry railroad tracks across the Susquehanna River just north of Harrisburg, Pennsylvania, the Rockville Stone Arch Bridge, at 3,820 feet long and 52 feet wide, is believed to be the longest and widest stone-arch railroad bridge in the world. A central…
Read MoreThe Salginatobel Bridge, spanning the Salgina Valley ravine, is the earliest surviving three-hinged, hollow box arch bridge designed by Robert Maillart.
Maillart's 1901 invention of the concrete hollow box design became a major bridge building concept. In this design, the concrete arch…
Read MoreThe Second Street Bridge is a simply ornamented, wrought-iron structure. It is 18 feet wide and spans 225 feet over the Kalamazoo River. It was built to replace a dilapidated wooden bridge that had served the area for nearly 50 years.
The bridge is anchored to fieldstone abutments on…
Read MoreSewall's Bridge is a singular example of an era when wooden trestle bridges carried highway traffic across New England waterways. It is the earliest pile-trestle bridge for which an authentic construction record exists, and the oldest for which builder's drawings survive. Spanning the York River…
Read MoreThree rivers - the Allegheny, Monongahela, and Ohio - join in Pittsburgh, making the city a natural site for the building of bridges. But the Smithfield Street Bridge stands apart from other Pittsburgh bridges for several reasons: it replaced structures by two well-known bridge engineers, Lewis…
Read MoreThe Starrucca Viaduct of the Erie Railroad Company crosses Starrucca Creek in Lanesboro, Pennsylvania. It is one of the oldest and one of the longest railroad bridges in Pennsylvania. Its 18 slender, semicircular stone arches each span 50 feet and the structure rises 110 feet above the creek.…
Read MoreThe design of the Sydney Harbour Bridge closely resembles the Hell Gate Bridge over the East River in New York City, conceived in 1916 by noted engineer Gustav Lindenthal and his chief assistant, O.H. Ammann.
The Sydney Harbour Bridge, with a span of 1,650 feet, is not only the longest…
Read MoreBuilt between 1819 and 1826, the Menai Bridge was the major structure on Britain's strategically important Holyhead Road connecting London with Holyhead and by sea to Ireland. Designed by Thomas Telford, the bridge's main span was 579 feet from tower to tower, the longest that had ever been…
Read MoreThe Triborough Bridge Project is a three-branched waterway crossing that connects Manhattan, the Bronx, and Queens at a junction of the East River and the Harlem River in New York City. The complex structure includes a suspension bridge from Wards Island to Queens, a vertical lift span from…
Read MoreThe design of the Bollman Truss Bridge-patented in 1852 and one of the first to use iron exclusively in all essential structural elements-was critical in the rapid expansion of American railroads in the 19th century. Replacing wooden bridges, which were cumbersome to build and vulnerable to…
Read MoreThis majestic viaduct was built during the golden age of railroading. It was at the western end of a major readjustment in grade and alignment of the Erie-Lackawanna Railroad, and had double tracks to carry the trains across the valley of Tunkhannock Creek. The Hallstead cutoff (between Scranton…
Read MoreThe bridge is 408 meters long and weighed approximately 1,500 metric tons when built. Originally supported by four columns, two more were added in later years to support the weight of heavier rail cars.
In the late 19th century, the Malleco River represented the border between the…
Read MoreDesigned by David B. Steinman, of Robinson & Steinman, New York City, the Waldo-Hancock suspension Bridge is a significant example of Steinman's work. David Steinman is considered among the most important suspension bridge designers of the 20th century. He earned an engineering degree from…
Read MoreThe structure has two segments: an East Channel bridge consisting of four 175-foot spans and three 240-foot spans crossing from Harrisburg to City Island; and a West Channel bridge, consisting of seven 175-foot spans crossing from City Island to Wormleysburg.
With 15 truss spans totaling…
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