ASCE

The Delaware Aqueduct provided an important transportation link between the Pennsylvania's coalmines and New York's booming industrial marketplace. It is the earliest surviving work of John A. Roebling, who designed the Brooklyn Bridge  30 years later. The cable anchorage system first used on this project was also used on the Brooklyn Bridge. The aqueduct is patterned after Roebling's design of the Pennsylvania Canal over the Allegheny River, and is the oldest metal strand cable suspension bridge still standing in the U.S.

Before the Davis Island Lock & Dam were built, the flow of the Ohio River slowed to little more than a trickle during dry periods. For several months each year, the unreliable flow stranded Pittsburgh's steamboats, towboats, and barges.    

The Davis Island Lock & Chanoine Dam experimental project was the first lock and dam ever constructed on the Ohio River. Its achievements also included the first rolling lock gates, the largest movable dam built in the 19th century, and the widest chamber in world history.    

The largest rolled-earth fill dam in the world at the time of its completion, Denison Dam eventually served as a prototype for dam construction in future U.S. Army Corps of Engineers projects throughout the arid plains of the American Southwest. Procedures and equipment developed during its construction are now commonplace in the sampling and testing of soils.

Winding over 64 miles through the majestic San Juan mountains, the narrow-gauge railway known today as the Cumbres and Toltec Scenic Railroad was built as a branch of the extensive Denver and Rio Grande Western Railroad that ran through western Colorado and most of Utah. It originally served the large number of settlers flocking to the gold and silver mines of the region.

One of four single-track tunnels built by the Blue Ridge Railroad, the 4,273-foot Crozet Tunnel was constructed at a time when hand drills, pickaxes, and black powder amounted to state-of-the-art tunneling technology. At the time of its completion, it was the longest railroad tunnel in the world. Envisioned and built by Claudius Crozet, a French-born educator and civil engineer, the tunnel remains a testament to his belief in advancing rail transportation even when faced with numerous difficulties. 

Inferior water and the lack of a sufficient water supply prompted public pressure to find a significant water source for the 360,000 of people living in New York City at the time. Studies determined that the Croton River, 40 miles north of the city, was the best available source. The original system served as a prototype for large-scale water supply projects across America. 

This elegant cast iron arch bridge designed by Scotland's famous Thomas Telford was built from 1812 to 1814.  It is the earliest surviving example of a portable lattice-braced standard type that Telford developed for use at wide and deep water crossing sites unsuitable for masonry spans.  At least 10 of these bridge types were erected throughout Britain between 1814 and 1829.

In 1899, engineers from the City of Chicago's Division of Bridges and Viaducts performed a survey of moveable bridge design in the U.S. and Europe. Their study led to the conclusion that the unusual trunnion bascule design would best meet their needs.

The Cornish-Windsor Covered Bridge is the longest wooden bridge in the United States and the longest two-span, covered bridge in the world. It is also a classic example of wooden bridge-building in 19th-century America. With copious supplies of timber at hand and a generous reserve of carpentry skills available, bridge builders in early America quickly discarded the masonry arches prevalent in the Old World. Instead, they opted for a revival of timber-truss designs dating from 14th century Europe.

Built by Robert Stephenson to carry the Chester and Holyhead Railway across the River Conwy, this bridge was erected between 1846 and 1848. It consists of a single span 400 feet long, formed by two parallel rectangular wrought iron tubes, each weighing 1300 tons. Masonry towers were built on the abutments and topped with battlements and turrets to harmonize with the nearby Conwy Castle. The Conwy Tubular Bridge was the first railway bridge in which trains ran through the main girders. It represents a pioneering use of wrought iron for bridges.