ASCE

A product of the Northern California Gold Rush, the Bridgeport Covered Bridge is believed to be the longest, single-span, wooden covered bridge in the United States. Crossing the south fork of the Yuba River at a span of 233 feet, the bridge was built by the Virginia City Turnpike Company as part of a 14-mile toll road authorized by the California state legislature. The toll road was an essential link connecting Virginia City, Nevada, and the silver-producing Comstock Lode with the centers of California commerce.

By the 1890s, the transportation infrastructure of downtown Boston - a maze of narrow, winding streets laid out, in some cases, along Colonial cow paths - proved completely inadequate for the needs of a modern, bustling metropolis. Tremont Street, the city's main thoroughfare, was regularly subject to gridlock from a convergence of foot traffic, horse-drawn conveyances, trolley lines, and electric streetcars. To rectify the problem, the Boston Transit Commission, with Howard A. Carson as chief engineer, was created in 1894 to study remedies. 

Nicholas Montgomery Powers built the bridge. It was first constructed behind the village, then taken apart and reassembled over the stream. Some residents questioned the idea of re-constructing it, but Powers was so confident of the bridge's durability that he sat on the roof when the final trestles supporting it were removed. From his perch he reportedly said: "If the bridge goes down, I never want to see the sun rise again!"

All building materials were made fire-resistant to protect against incendiary bombing. Treatment involved a vacuum process of salt impregnation. During construction, high winds caused a partial collapse of some members. The ruined materials were piled for incineration, but would not burn; so the rubble was buried on site. Years later, a farmer leasing ground on the site plowed up some of the materials. They were reported to still be in good condition.

Soon after gold was discovered at Sutter's Mill near Sacramento in 1848, General John Bidwell found gold near the Middle Fork of the Feather River. His discovery brought hordes of miners to the scene and Bidwell Bar was born. The Bidwell Bar Suspension Bridge over the Feather River was one of several suspension bridges built in the region in the 1850s, and is the only one that remains.

The first known pumping system providing drinking and wash water in the North American colonies. The building (still standing) is dated 1761, but it was preceded by an experimental frame building dated 1754. Before the Bethlehem built its system, assigned carriers would daily haul water up the hill from a well near the city gate. A wooden waterwheel, driven by the flow of Monocacy Creek, drove wooden pumps which lifted the water through wooden pipes to the top of the hill where the water was distributed by gravity.

Belle Fourche, meaning "Beautiful Forks" in French, refers to the confluence of the Redwater and Belle Fourche Rivers. The gold rush to the Black Hills in 1876 brought many people to the area, but agriculture and livestock soon became the principal industries. Farmers and civic leaders recognized the need for a reliable source of irrigation water in this semi-arid region and petitioned the Federal government for funds to build an irrigation and flood control system.

Montogomery Bell was a land developer and iron maker who purchased the Harpeth Narrows site to expand his industrial empire - which ultimately consisted of 14 iron blast furnaces throughout middle Tennessee.

The Harpeth River makes a tight bend around a steep limestone ridge, losing 17 feet of elevation in a run of 5 1/2 miles. Bell excavated a tunnel through the limestone ridge, creating a shortcut for the river. The hydropower derived from this drop in elevation was used to drive the Patterson Iron Works built by Bell.

The longest steel-arch bridge in the world for 46 years, the Bayonne Bridge continues to be celebrated today as a major aesthetic and technical achievement. The 1,675-foot bridge replaced a ferry service which until then was the only means of crossing from  the Bayonne peninsula to Staten Island. While providing this essential link in the transportation network of greater New York City, the bridge's mid-span clearance of 150 feet also allows for unobstructed navigation on Newark Bay, the main shipping channel to the inland ports of Newark and Elizabeth, New Jersey.

"The roundhouse is an amazing survivor of an important era in American engineering and architectural history. Eric DeLony, chief of the National Park Service's Historic American Engineering Record, has called it 'the most important surviving cast-iron framed building in North America.'"   
From: The Baltimore and Ohio Railroad Martinsburg Shop Complex: Historic Structure Report. By John P. Hankey, August, 2000.