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25-602: The Mathematical Bridge is a wooden footbridge in the southwest of central Cambridge , England . It bridges the River Cam about one hundred feet northwest of Silver Street Bridge and connects two parts of Queens' College . Its official name is simply the Wooden Bridge or Queens' Bridge . It is a Grade II listed building. The bridge was designed by William Etheridge , and built by James Essex in 1749. It has been rebuilt on two occasions, in 1866 and in 1905, but has kept

50-502: A 'new' wooden bridge across the lake that was used until 1878 – measuring approximately 1,450 metres (4,760 ft) in length and 4 metres (13 ft) wide. On April 6, 2001, the reconstructed wooden footbridge was opened, being the longest wooden bridge in Switzerland. The Kapellbrücke is a 204-metre-long (669 ft) bridge crossing the Reuss in the city of Lucerne in Switzerland. It is

75-487: A licensed engineer be hired to insure the bridge design is safe and appropriate for the site. Using fallen trees, stringer bridges can be built. Wood laminated by stress, glued, dowels, or nails lumber are good for panel bridges. New lumber and wood scavenged from buildings and railroad ties can be used to build stringer bridges. A licensed engineer can help operators design a safe, appropriate timber bridge. Personnel from Virginia Tech have described in detail how to build

100-549: A new collection of innovations to champion every two years that merit accelerated deployment. Among the approaches promoted by the EDC effort are: adaptive traffic control to reduce fuel consumption and improve travel time reliability ; alternative intersection design; prefabricated bridge elements and systems; high-friction surface treatments; warm mix asphalt; ultra-high-performance concrete; virtual public involvement; and time-saving strategies such as rapid bridge replacement . Since

125-539: A question based on the LTPP data. In 2010, FHWA launched the Every Day Counts (EDC) initiative to identify and deploy innovations to reduce project delivery time, enhance safety, and protect the environment. EDC is a state-based model that rapidly deploys proven, yet underutilized innovations. FHWA works with State transportation departments, local governments, tribes, private industry, and other stakeholders to identify

150-556: A stringer bridge using standard bridge design procedures, for example, by placing timber stringers across the abutment , using a bent to support a trestle or timber frame . Their methods are quick and cost little. Federal Highway Administration The Federal Highway Administration ( FHWA ) is a division of the United States Department of Transportation that specializes in highway transportation. The agency's major activities are grouped into two programs,

175-561: Is a renewable resource , it is relatively economical, and there have been rapid improvements in design, construction, and preservative treatment. The US Congress emphasized timber bridges by passing the Timber Bridge Initiative (TBI) in 1988 and the Intermodal Surface Transportation and Efficiency Act (ISTEA) in 1991. Covered bridges , usually made of wood and enclosed as if a tunnel, were very popular in

200-403: Is a series of tangents that describe the arc of the bridge, with radial members to tie the tangents together and triangulate the structure, making it rigid and self-supporting. This type of structure, technically tangent and radial trussing , is an efficient structural use of timber, and was also used for the timber supporting arches ( centring ) used for building stone bridges. Analysis of

225-658: The Manual on Uniform Traffic Control Devices (MUTCD), which is used by most highway agencies in the United States. The MUTCD provides such standards as the size, color and height of traffic signs , traffic signals and road surface markings . Long-Term Pavement Performance (LTPP) is a program supported by the FHWA to collect and analyse road data. The LTPP program was initiated by the Transportation Research Board (TRB) of

250-606: The Holzbrücke Rapperswil-Hurden crossing upper Lake Zürich in Switzerland; the prehistoric timber piles discovered to the west of the Seedamm date back to 1523 B.C. The first wooden footbridge led across Lake Zürich , followed by several reconstructions at least until the late 2nd century AD, when the Roman Empire built a 6-metre-wide (20 ft) wooden bridge. Between 1358 and 1360, Rudolf IV, Duke of Austria , built

275-610: The National Research Council (NRC) in the early 1980s. The FHWA with the cooperation of the American Association of State Highway and Transportation Officials (AASHTO) sponsored the program. As a result of this program, the FHWA has collected a huge database of road performance. The FHWA and the ASCE hold an annual contest known as LTPP International Data Analysis Contest , which is based on challenging researchers to answer

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300-823: The 19th century in the US. Today, timber bridges are promoted as environmentally friendly, and as a way to protect water quality and the habitat along waterways. Timber bridges can be placed over small streams or channels with firm, stable banks. The passing of TBI and ISTEA by the US Congress has provided an impetus to identify and develop standard designs for timber bridges, which the US Forest Service has done. The US Forest Service has designed standardized plans for timber bridge superstructures made of treated lumber. The University of Minnesota Extension Service recommends three types of timber bridges for wilderness lands, and suggest that

325-536: The American Association for Highway Improvement was organized. Funding came from automobile registration, and taxes on motor fuels, as well as state aid. By 1914, there were 2.4 million miles of rural dirt rural roads; 100,000 miles had been improved with grading and gravel, and 3,000 miles were given high-quality surfacing. The rapidly increasing speed of automobiles, and especially trucks, made maintenance and repair high-priority items. In 1915, OPR's name

350-739: The Federal Lands Highway Program (sometimes called "direct fed"), the FHWA provides highway design and construction services for various federal land-management agencies, such as the Forest Service and the National Park Service . In addition to these programs, the FHWA performs and sponsors research in the areas of roadway safety, congestion, highway materials and construction methods, and provides funding to local technical assistance program centers to disseminate research results to local highway agencies. The FHWA also publishes

375-623: The Federal-aid Highway Program and the Federal Lands Highway Program. Its role had previously been performed by the Office of Road Inquiry , Office of Public Roads and the Bureau of Public Roads . With the coming of the bicycle in the 1890s, interest grew regarding the improvement of streets and roads in America. The traditional method of putting the burden on maintaining roads on local landowners

400-456: The design shows that the tangent members are almost entirely under compression, while the radial timbers are almost entirely subject to tension with very little bending stress, or to put it another way, the tangent and radial elements elegantly express the forces involved in arched construction. A popular fable is that the bridge was designed and built by Sir Isaac Newton without the use of nuts or bolts. Various stories relate how at some point in

425-513: The inception of EDC, each state has used 26 or more of the 57 innovations and some states have deployed more than 45. Many of these practices have become mainstream practices across the country. The Federal Highway Administration is overseen by an administrator appointed by the President of the United States by and with the consent of the United States Senate . The administrator works under

450-400: The inside of the parapets, explaining why bolts were thought to be an addition to the original. Newton could not have been directly involved since he died in 1727, twenty-two years before the bridge was constructed. Wooden bridge The most ancient form of timber bridge is the log bridge , created by felling a tree over a gap needing to be crossed. Among the oldest timber bridges is

475-749: The new U.S. Department of Transportation . The FHWA took over the functions of the Bureau of Public Roads the following year. The FHWA's role in the Federal-aid Highway Program is to oversee federal funds to build and maintain the National Highway System (primarily Interstate highways , U.S. highways and most state highways). This funding mostly comes from the federal gasoline tax and mostly goes to state departments of transportation . The FHWA oversees projects using these funds to ensure that federal requirements for project eligibility, contract administration and construction standards are adhered to. Under

500-636: The oldest wooden covered bridge in Europe, and one of Switzerland's main tourist attractions. Recently timber bridges have received attention in the United States because they are environmentally friendly compared to other bridge types. Until 1991, the Federal Highway Administration has concentrated on major highways and other primary roads; rural highways and local roads, where timber bridges are mostly found, have received less attention. Local and state agencies prefer timber bridges because timber

525-628: The organization was once again named the Bureau of Public Roads; it was placed under the Department of Commerce . From 1917 through 1941, 261,000 miles of highways were built with $ 3.17 billion in federal aid and $ 2.14 billion in state and local funds. The Federal Highway Administration was created on October 15, 1966, along with the Bureau of Motor Carrier Safety and the National Highway Safety Bureau (now known as National Highway Traffic Safety Administration ), as part of

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550-476: The past either students or fellows of the University attempted to take the bridge apart and put it back together, but were unable to work out how to hold the structure together, and were obliged to resort to adding nuts and bolts. In reality, bolts or the equivalent are an inherent part of the design. When it was first built, iron spikes were driven into the joints from the outer side, where they could not be seen from

575-645: The same overall design. Although it appears to be an arch, it is composed entirely of straight timbers built to an unusually sophisticated engineering design, hence the name. A replica of the bridge was built in 1923 near the Iffley Lock in Oxford . The original Mathematical Bridge was another bridge of the same design, also commissioned by James Essex, crossing the Cam between Trinity and Trinity Hall colleges, where Garret Hostel Bridge now stands. The arrangement of timbers

600-639: Was changed to the Bureau of Public Roads . The following year, federal aid was first made available to improve post roads and promote general commerce: $ 75 million over five years, issued through the BPR in cooperation with the state highway departments. In 1939, BPR was renamed to the Public Roads Administration (PRA) and shifted to the Federal Works Agency . After the FWA was abolished in 1949,

625-430: Was increasingly inadequate. In 1893, the federal Office of Road Inquiry (ORI) was founded; in 1905, it was renamed the Office of Public Roads (OPR) and made a division of the United States Department of Agriculture . Demands grew for local and state government to take charge. With the coming of the automobile, urgent efforts were made to upgrade and modernize dirt roads designed for horse-drawn wagon traffic. In 1910,

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