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82-491: The Puget Sound Regional Council (PSRC) is a metropolitan planning organization that develops policies and makes decisions about transportation planning , economic development , and growth management throughout the four-county Seattle metropolitan area surrounding Puget Sound . It is a forum for cities , towns , counties , transit agencies, port districts , Native American tribes , and state agencies to address regional issues. The Puget Sound Regional Council serves

164-600: A bridge-restaurant which is a bridge built to serve as a restaurant. Other suspension bridge towers carry transmission antennas. Conservationists use wildlife overpasses to reduce habitat fragmentation and animal-vehicle collisions. The first animal bridges sprung up in France in the 1950s, and these types of bridges are now used worldwide to protect both large and small wildlife. Bridges are subject to unplanned uses as well. The areas underneath some bridges have become makeshift shelters and homes to homeless people, and

246-658: A bicycle and walking trail, as well as preserving freight services along the northern segment. For the longer term (10–40 years), the study recommended planning for high-capacity commuter rail. In 2008 the Washington State Legislature requested that Sound Transit and PSRC evaluate the feasibility of commuter rail in the BNSF Woodinville Subdivision along the east side of Lake Washington . The report, prepared by Parsons Brinckerhoff , found that it would be "feasible through

328-525: A bridge is to be designed, standards authorities specify simplified notional load models, notably HL-93, intended to give the same load effects as the characteristic maximum values. The Eurocode is an example of a standard for bridge traffic loading that was developed in this way. Most bridge standards are only applicable for short and medium spans - for example, the Eurocode is only applicable for loaded lengths up to 200 m. Longer spans are dealt with on

410-471: A case-by-case basis. It is generally accepted that the intensity of load reduces as span increases because the probability of many trucks being closely spaced and extremely heavy reduces as the number of trucks involved increases. It is also generally assumed that short spans are governed by a small number of trucks traveling at high speed, with an allowance for dynamics. Longer spans on the other hand, are governed by congested traffic and no allowance for dynamics

492-480: A combination of structural health monitoring and testing. This is regulated in country-specific engineer standards and includes an ongoing monitoring every three to six months, a simple test or inspection every two to three years and a major inspection every six to ten years. In Europe, the cost of maintenance is considerable and is higher in some countries than spending on new bridges. The lifetime of welded steel bridges can be significantly extended by aftertreatment of

574-399: A different site, and re-used. They are important in military engineering and are also used to carry traffic while an old bridge is being rebuilt. Movable bridges are designed to move out of the way of boats or other kinds of traffic, which would otherwise be too tall to fit. These are generally electrically powered. The Tank bridge transporter (TBT) has the same cross-country performance as

656-606: A few will predominate. The separation of forces and moments may be quite clear. In a suspension or cable-stayed bridge , the elements in tension are distinct in shape and placement. In other cases the forces may be distributed among a large number of members, as in a truss. The world's longest beam bridge is Lake Pontchartrain Causeway in southern Louisiana in the United States, at 23.83 miles (38.35 km), with individual spans of 56 feet (17 m). Beam bridges are

738-581: A form of boardwalk across marshes ; examples of such bridges include the Sweet Track and the Post Track in England, approximately 6000 years old. Ancient people would also have used log bridges consisting of logs that fell naturally or were intentionally felled or placed across streams. Some of the first human-made bridges with significant span were probably intentionally felled trees. Among

820-666: A former network of roads, designed to accommodate chariots , between the fort of Tiryns and town of Epidauros in the Peloponnese , in southern Greece . Dating to the Greek Bronze Age (13th century BC), it is one of the oldest arch bridges still in existence and use. Several intact, arched stone bridges from the Hellenistic era can be found in the Peloponnese. The greatest bridge builders of antiquity were

902-429: A high quality of life come 2040, when the region's population is expected to reach 5 million. The document analyzes policies in response to the needs of housing, economic development, transportation, and the environment. It identifies infrastructure investments that would contribute to the region's and its residents' well-being and suggests a financing plan for the investments. The " BNSF Corridor Preservation Study"

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984-541: A larger regional role in planning. It was the "first time" that transportation projects were selected by elected officials with significant public input. The agency was headquartered at Waterfront Place in Downtown Seattle for most of its history. PSRC announced in 2023 that they would move to a fifth-story space at 1201 Third Avenue with the signing of a 13.5-year lease. The new office opened on January 25, 2024. PSRC conducts long-range planning (20‑30 years in

1066-452: A major conceptual shift for many MPOs (and others in the planning community), since the imposition of fiscal discipline on plans now required, not only understanding how much money might be available, but how to prioritize investment needs and make difficult choices among competing needs. Adding to this complexity is the need to plan across transportation modes and develop approaches for multimodal investment prioritization and decision making. It

1148-593: A span of 552 m (1,811 ft). The bridge was opened 29 April 2009, in Chongqing , China. The longest suspension bridge in the world is the 4,608 m (15,118 ft) 1915 Çanakkale Bridge in Turkey. The longest cable-stayed bridge since 2012 is the 1,104 m (3,622 ft) Russky Bridge in Vladivostok , Russia. Some Engineers sub-divide 'beam' bridges into slab, beam-and-slab and box girder on

1230-749: A stream. Often in palaces, a bridge will be built over an artificial waterway as symbolic of a passage to an important place or state of mind. A set of five bridges cross a sinuous waterway in an important courtyard of the Forbidden City in Beijing, China. The central bridge was reserved exclusively for the use of the Emperor and Empress, with their attendants. The estimated life of bridges varies between 25 and 80 years depending on location and material. Bridges may age hundred years with proper maintenance and rehabilitation. Bridge maintenance consisting of

1312-469: A strong central Puget Sound economy". It was launched in November 2004 and has accrued more than 300 member organizations. Achievements include: The Puget Sound Regional Council is governed by elected officials from its member government agencies, who meet annually as a General Assembly to approve the budget and elect new leaders. A 32‑member Executive Board meets monthly to make decisions on behalf of

1394-489: A tank even when fully loaded. It can deploy, drop off and load bridges independently, but it cannot recover them. Double-decked (or double-decker) bridges have two levels, such as the George Washington Bridge , connecting New York City to Bergen County , New Jersey , US, as the world's busiest bridge, carrying 102 million vehicles annually; truss work between the roadway levels provided stiffness to

1476-418: A variety of capital improvements to facilitate higher speeds" within the range of capital cost estimates of similar projects in the United States, "although at the high end of that range" due to the dilapidated infrastructure and the absence of safety and communications systems. The Prosperity Partnership is a coalition of public- and private-sector organizations as well as nonprofits that is "working to promote

1558-462: Is a bridge that carries water, resembling a viaduct, which is a bridge that connects points of equal height. A road-rail bridge carries both road and rail traffic. Overway is a term for a bridge that separates incompatible intersecting traffic, especially road and rail. Some bridges accommodate other purposes, such as the tower of Nový Most Bridge in Bratislava , which features a restaurant, or

1640-470: Is also historically significant as it is the world's oldest open-spandrel stone segmental arch bridge. European segmental arch bridges date back to at least the Alconétar Bridge (approximately 2nd century AD), while the enormous Roman era Trajan's Bridge (105 AD) featured open-spandrel segmental arches in wooden construction. Rope bridges , a simple type of suspension bridge , were used by

1722-588: Is an early example of a double-decked bridge. The upper level carries a railway, and the lower level is used for road traffic. Other examples include Britannia Bridge over the Menai Strait and Craigavon Bridge in Derry, Northern Ireland. The Oresund Bridge between Copenhagen and Malmö consists of a four-lane highway on the upper level and a pair of railway tracks at the lower level. Tower Bridge in London

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1804-496: Is different example of a double-decked bridge, with the central section consisting of a low-level bascule span and a high-level footbridge . A viaduct is made up of multiple bridges connected into one longer structure. The longest and some of the highest bridges are viaducts, such as the Lake Pontchartrain Causeway and Millau Viaduct . A multi-way bridge has three or more separate spans which meet near

1886-698: Is in this context of greater prominence, funding, and requirements that MPOs function today. An annual element is composed of transportation improvement projects contained in an area's transportation improvement program (TIP), which is proposed for implementation during the current year. The annual element is submitted to the U.S. Department of Transportation as part of the required planning process. The passage of Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users SAFETEA-LU in 2005 created new and revised requirements for transportation planning and programs. Although SAFETEA-LU increased standards, most MPOs already were in compliance with

1968-417: Is led by architects, bridges are usually designed by engineers. This follows from the importance of the engineering requirements; namely spanning the obstacle and having the durability to survive, with minimal maintenance, in an aggressive outdoor environment. Bridges are first analysed; the bending moment and shear force distributions are calculated due to the applied loads. For this, the finite element method

2050-540: Is needed. Calculating the loading due to congested traffic remains a challenge as there is a paucity of data on inter-vehicle gaps, both within-lane and inter-lane, in congested conditions. Weigh-in-Motion (WIM) systems provide data on inter-vehicle gaps but only operate well in free flowing traffic conditions. Some authors have used cameras to measure gaps and vehicle lengths in jammed situations and have inferred weights from lengths using WIM data. Others have used microsimulation to generate typical clusters of vehicles on

2132-515: Is one of the key roles that the technical committee supports. The technical committee typically comprises staff-level officials of local, state, and federal agencies. In addition, a technical committee may include representatives of interest groups, various transportation modes, and local citizens. A 2005 survey of MPOs nationally commissioned in preparation of "Special Report 288" of the Transportation Research Board of

2214-737: Is the most popular. The analysis can be one-, two-, or three-dimensional. For the majority of bridges, a two-dimensional plate model (often with stiffening beams) is sufficient or an upstand finite element model. On completion of the analysis, the bridge is designed to resist the applied bending moments and shear forces, section sizes are selected with sufficient capacity to resist the stresses. Many bridges are made of prestressed concrete which has good durability properties, either by pre-tensioning of beams prior to installation or post-tensioning on site. In most countries, bridges, like other structures, are designed according to Load and Resistance Factor Design (LRFD) principles. In simple terms, this means that

2296-510: The Inca civilization in the Andes mountains of South America, just prior to European colonization in the 16th century. The Ashanti built bridges over streams and rivers . They were constructed by pounding four large forked tree trunks into the stream bed, placing beams along these forked pillars, then positioning cross-beams that were finally covered with four to six inches of dirt. During

2378-882: The Metropolitan Council is the MPO. An example of a medium-sized MPO is the Lexington Area MPO in Kentucky . An example of a small MPO is the Kittery Area MPO in Maine . Another MPO planning organization has developed in the area of western central Florida . Several MPOs there, with governance over eight counties, have developed a greater regional planning committee, the Chairs Coordinating Committee (CCC), composed of

2460-751: The National Academies found that "forecast by negotiation" was a common method of projecting future population and employment growth for use in travel forecasting , suggesting rent-seeking behavior on the part of MPO committees influencing the technical staff. Usually MPOs retain a core professional staff in order to ensure the ability to carry out the required metropolitan planning process in an effective and expeditious manner. The size and qualifications of this staff may vary by MPO, since no two metropolitan areas have identical planning needs Most MPOs, however, require at least some staff dedicated solely to MPO process oversight and management because of

2542-552: The Roman era , as the technology for cement was lost (then later rediscovered). In India, the Arthashastra treatise by Kautilya mentions the construction of dams and bridges. A Mauryan bridge near Girnar was surveyed by James Princep . The bridge was swept away during a flood, and later repaired by Puspagupta, the chief architect of emperor Chandragupta I . The use of stronger bridges using plaited bamboo and iron chain

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2624-864: The University of Minnesota ). Likewise, in Toronto , the Prince Edward Viaduct has five lanes of motor traffic, bicycle lanes, and sidewalks on its upper deck; and a pair of tracks for the Bloor–Danforth subway line on its lower deck. The western span of the San Francisco–Oakland Bay Bridge also has two levels. Robert Stephenson 's High Level Bridge across the River Tyne in Newcastle upon Tyne , completed in 1849,

2706-608: The ancient Romans . The Romans built arch bridges and aqueducts that could stand in conditions that would damage or destroy earlier designs, some of which still stand today. An example is the Alcántara Bridge , built over the river Tagus , in Spain. The Romans also used cement, which reduced the variation of strength found in natural stone. One type of cement, called pozzolana , consisted of water, lime , sand, and volcanic rock . Brick and mortar bridges were built after

2788-504: The river Severn . With the Industrial Revolution in the 19th century, truss systems of wrought iron were developed for larger bridges, but iron does not have the tensile strength to support large loads. With the advent of steel, which has a high tensile strength, much larger bridges were built, many using the ideas of Gustave Eiffel . In Canada and the United States, numerous timber covered bridges were built in

2870-523: The 18th century, there were many innovations in the design of timber bridges by Hans Ulrich Grubenmann , Johannes Grubenmann , as well as others. The first book on bridge engineering was written by Hubert Gautier in 1716. A major breakthrough in bridge technology came with the erection of the Iron Bridge in Shropshire, England in 1779. It used cast iron for the first time as arches to cross

2952-588: The Federal Highway Administration), and the U.S. Department of Housing and Urban Development . The study, completed in 1967, offered recommendations regarding transportation policy as well as land-use planning ; its publication set the precedent of taking on " transportation planning duties previously done by Washington State ". Its membership continued to expand to smaller suburban cities and tribal councils. In 1973 Washington Governor Daniel J. Evans designated PSGC as an MPO for

3034-518: The General Assembly, along with several advisory boards composed of local elected officials and representatives of business, labor, environmental, and community interests. The federal government provides the largest portion of PSRC's funding—74% of the total annual budget. Approximately 20% comes from membership dues and the remaining 6% comes from state grants. Metropolitan planning organization Purposes of MPOs: In other words,

3116-478: The MPO setting. Federal law, however, does not require members of an MPO policy committee to be representatives of the metropolitan areas' populations. Systematic studies have found that MPO policy committees' representations of urban municipalities and disadvantaged minority populations in their areas are less than proportional to population. The policy committee's responsibilities include debating and making decisions on key MPO actions and issues, including adoption of

3198-624: The appearance of the bridge can have great importance. Often, this is the case with a large bridge that serves as an entrance to a city, or crosses over a main harbor entrance. These are sometimes known as signature bridges. Designers of bridges in parks and along parkways often place more importance on aesthetics, as well. Examples include the stone-faced bridges along the Taconic State Parkway in New York. Bridges are typically more aesthetically pleasing if they are simple in shape,

3280-643: The attention of the general public in the 1990s by the novel, movie and play The Bridges of Madison County . In 1927, welding pioneer Stefan Bryła designed the first welded road bridge in the world, the Maurzyce Bridge which was later built across the river Słudwia at Maurzyce near Łowicz , Poland in 1929. In 1995, the American Welding Society presented the Historic Welded Structure Award for

3362-596: The basis of their cross-section. A slab can be solid or voided (though this is no longer favored for inspectability reasons) while beam-and-slab consists of concrete or steel girders connected by a concrete slab. A box-girder cross-section consists of a single-cell or multi-cellular box. In recent years, integral bridge construction has also become popular. Most bridges are fixed bridges, meaning they have no moving parts and stay in one place until they fail or are demolished. Temporary bridges, such as Bailey bridges , are designed to be assembled, taken apart, transported to

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3444-432: The bridge is constructed and anchored, the material used to make it, and the funds available to build it. The earliest bridges were likely made with fallen trees and stepping stones . The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge , dating from the 13th century BC, in the Peloponnese is one of the oldest arch bridges in existence and use. The Oxford English Dictionary traces

3526-437: The bridge to Poland. Bridges can be categorized in several different ways. Common categories include the type of structural elements used, by what they carry, whether they are fixed or movable, and by the materials used. Bridges may be classified by how the actions of tension , compression , bending , torsion and shear are distributed through their structure. Most bridges will employ all of these to some degree, but only

3608-439: The center of the bridge. Multi-way bridges with only three spans appear as a "T" or "Y" when viewed from above. Multi-way bridges are extremely rare. The Tridge , Margaret Bridge , and Zanesville Y-Bridge are examples. A bridge can be categorized by what it is designed to carry, such as trains, pedestrian or road traffic ( road bridge ), a pipeline ( Pipe bridge ) or waterway for water transport or barge traffic. An aqueduct

3690-690: The central Puget Sound region of Washington state. The region is made up of King County , Kitsap County , Pierce County , and Snohomish County , which collectively encompass 6,290 square miles (16,300 km) and comprise 73 cities and towns. The five major cities are Seattle , Bellevue in King County, Tacoma in Pierce County, Everett in Snohomish County, and Bremerton in Kitsap County. The region's population

3772-451: The chairs of seven MPOs and the chairs of their appointed advisory committee (or their representatives) in order to coordinate transportation planning for the region, that is compatible with all, as well as addressing the challenges of long range planning for a large and growing region that has overlapping issues among the MPOs or transportation plans that extend throughout the entire area. Often

3854-527: The complexity of the process and need to ensure that requirements are properly addressed. There are five core functions of an MPO: If the metropolitan area is designated as an air quality non-attainment or maintenance area, then Presently, most MPOs have no authority to raise revenues such as to levy taxes on their own, rather, they are designed to allow local officials to decide collaboratively how to spend available federal and other governmental transportation funds in their urbanized areas. The funding for

3936-467: The deck is thinner in proportion to its span, the lines of the structure are continuous, and the shapes of the structural elements reflect the forces acting on them. To create a beautiful image, some bridges are built much taller than necessary. This type, often found in east-Asian style gardens, is called a Moon bridge , evoking a rising full moon. Other garden bridges may cross only a dry bed of stream-washed pebbles, intended only to convey an impression of

4018-556: The economy. Indeed, PSRC maintains the regional Transportation Improvement Program (TIP), a database of nearly $ 12 billion in projects that are being financed between 2010 and 2013. Some examples of such projects include new bridges in Tacoma and Bothell , more efficient traffic signal timing in Redmond , and light rail construction to Northgate . VISION 2040 is PSRC's strategy to ensure that Puget Sound region residents have

4100-449: The environment, promote energy conservation, improve the quality of life, and promote consistency between transportation improvements and state and local planned growth and economic development patterns. There are a large number of metropolitan planning organizations in the United States. Bridge A bridge is a structure built to span a physical obstacle (such as a body of water , valley , road, or railway) without blocking

4182-423: The federal government requires that federal transportation funds be allocated to regions in a manner that has a basis in metropolitan plans developed through intergovernmental collaboration, rational analysis, and consensus-based decision making. Typically, an MPO governance structure includes a variety of committees as well as a professional staff. The "policy committee" is the top-level decision-making body for

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4264-423: The first time, state transportation officials were required to consult seriously with local representatives on MPO governing boards regarding matters of project prioritization and decision-making. These changes had their roots in the need to address increasingly difficult transportation problems—in particular, the more complicated patterns of traffic congestion that arose with the suburban development boom in

4346-405: The future) for growth management, transportation, and economic development. It also collects regional data on demographics , housing, unemployment , building permits , and traffic counts, and analyzes to inform public policy. PSRC President Josh Brown notes that "helping communities secure federal transportation funding " is a key priority because of its positive effects on employment growth and

4428-491: The lake. Between 1358 and 1360, Rudolf IV, Duke of Austria , built a 'new' wooden bridge across the lake that was used until 1878; it was approximately 1,450 metres (4,760 ft) long and 4 metres (13 ft) wide. On 6 April 2001, a reconstruction of the original wooden footbridge was opened; it is also the longest wooden bridge in Switzerland. The Arkadiko Bridge is one of four Mycenaean corbel arch bridges part of

4510-781: The late 1700s to the late 1800s, reminiscent of earlier designs in Germany and Switzerland. Some covered bridges were also built in Asia. In later years, some were partly made of stone or metal but the trusses were usually still made of wood; in the United States, there were three styles of trusses, the Queen Post, the Burr Arch and the Town Lattice. Hundreds of these structures still stand in North America. They were brought to

4592-427: The load is factored up by a factor greater than unity, while the resistance or capacity of the structure is factored down, by a factor less than unity. The effect of the factored load (stress, bending moment) should be less than the factored resistance to that effect. Both of these factors allow for uncertainty and are greater when the uncertainty is greater. Most bridges are utilitarian in appearance, but in some cases,

4674-418: The means to achieve important national goals including economic progress, cleaner air , energy conservation , and social equity . ISTEA promoted a transportation system in which different modes and facilities—highway, transit, pedestrian , bicycle , aviation , and marine —were integrated to allow a "seamless" movement of both goods and people. New funding programs provided greater flexibility in

4756-558: The members of the executive committee of an MPO act interchangeably as the representative to this seven-MPO regional committee. This committee meets less frequently than the participating MPOs. The enactment of the 1991 Intermodal Surface Transportation Efficiency Act (ISTEA) ushered in a "renaissance" for MPOs. After a decade or more of being consigned to a minimal role in transportation planning, ISTEA directed additional federal funding to MPOs, expanded their authority to select projects, and mandated new metropolitan planning initiatives. For

4838-422: The metropolitan long-range transportation plans, transportation improvement programs , annual planning work programs, budgets, and other policy documents. The policy committee also may play an active role in key decision points or milestones associated with MPO plans and studies, as well as conducting public hearings and meetings. An appointed advisory committee (CAC) develops the recommendations for consideration by

4920-639: The oldest timber bridges is the Holzbrücke Rapperswil-Hurden bridge that crossed upper Lake Zürich in Switzerland; prehistoric timber pilings discovered to the west of the Seedamm causeway date back to 1523 BC. The first wooden footbridge there led across Lake Zürich; it was reconstructed several times through the late 2nd century AD, when the Roman Empire built a 6-metre-wide (20 ft) wooden bridge to carry transport across

5002-407: The operations of an MPO comes from a combination of federal transportation funds and required matching funds from state and local governments. In some regions, MPOs have been given authority to handle expanded functions: MPOs differ greatly in various parts of the country and even within states. Some have large staffs, while others may include only a director and a transportation planner. Sometimes

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5084-495: The origin of the word bridge to an Old English word brycg , of the same meaning.   The Oxford English Dictionary also notes that there is some suggestion that the word can be traced directly back to Proto-Indo-European *bʰrēw-. However, they also note that "this poses semantic problems." The origin of the word for the card game of the same name is unknown.   The simplest and earliest types of bridges were stepping stones . Neolithic people also built

5166-629: The past, these load models were agreed by standard drafting committees of experts but today, this situation is changing. It is now possible to measure the components of bridge traffic load, to weigh trucks, using weigh-in-motion (WIM) technologies. With extensive WIM databases, it is possible to calculate the maximum expected load effect in the specified return period. This is an active area of research, addressing issues of opposing direction lanes, side-by-side (same direction) lanes, traffic growth, permit/non-permit vehicles and long-span bridges (see below). Rather than repeat this complex process every time

5248-405: The path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where

5330-425: The planning organization. In most MPOs, the policy committee comprises: With only a few unique exceptions nationwide, MPO policy committee members are not elected directly by citizens. Rather, a policy committee member typically is an elected or appointed official of one of the MPO's constituent local jurisdictions. The policy committee member thus has legal authority to speak and act on behalf of that jurisdiction in

5412-645: The planning process and to see that investment decisions contributed to meeting the air quality standards of the Clean Air Act Amendments . In addition, ISTEA placed a new requirement on MPOs to conduct "fiscally constrained planning", and ensure that long-range transportation plans and short-term transportation improvement programs were fiscally constrained; in other words, adopted plans and programs can not include more projects than reasonably can be expected to be funded through existing or projected sources of revenues. This new requirement represented

5494-538: The policy committee and establishes a ranked proposal for work plans. Most MPOs also establish a technical committee to act as an advisory body to the policy committee for transportation issues that primarily are technical in nature. The technical committee interacts with the MPO's professional staff on technical matters related to planning, analysis tasks, and projects. Through this work, the technical committee develops recommendations on projects and programs for policy committee consideration. Metropolitan travel forecasting

5576-566: The previous decades. Many recognized that the problems could only be addressed effectively through a stronger federal commitment to regional planning. The legislation that emerged, the Intermodal Surface Transportation Efficiency Act (ISTEA), was signed into federal law by President George H. W. Bush in December 1991. It focused on improving transportation, not as an end in itself, but as

5658-472: The principles of Load and Resistance Factor Design . Before factoring to allow for uncertainty, the load effect is generally considered to be the maximum characteristic value in a specified return period . Notably, in Europe, it is the maximum value expected in 1000 years. Bridge standards generally include a load model, deemed to represent the characteristic maximum load to be expected in the return period. In

5740-570: The professional staff of an MPO is provided by a county or a council of governments. In many urban areas, existing organizations such as county governments or councils of government also function as MPOs. The MPO role also may be played by an independent governmental organization or a regional government. In the Portland, Oregon, metropolitan area, for example, Metro is the MPO. In the Minneapolis-St. Paul, Minnesota , metropolitan area,

5822-634: The purposes of the Federal Aid Highway Act of 1973 . Two years later it decided to reorganize as the Puget Sound Council of Governments (PSCOG) and continued to expand. The Puget Sound Regional Council (PSRC) came into being in its current form in 1991 by an interlocal agreement and was designated an MPO by Washington Governor Booth Gardner . This occurred at the same time Congress passed the federal Intermodal Surface Transportation Efficiency Act (ISTEA), which allowed for

5904-440: The regulations. Some of the planning topic areas include transportation systems security, emergency preparedness, public participation plans for metropolitan planning, and requiring the electronic publication of plans and TIP/STIP by the MPOs. SAFETEA-LU requires that the statewide transportation planning process and the metropolitan planning process provide for consideration of projects and strategies that will protect and enhance

5986-763: The roadways and reduced movement of the upper level when the lower level was installed three decades after the upper level. The Tsing Ma Bridge and Kap Shui Mun Bridge in Hong Kong have six lanes on their upper decks, and on their lower decks there are two lanes and a pair of tracks for MTR metro trains. Some double-decked bridges only use one level for street traffic; the Washington Avenue Bridge in Minneapolis reserves its lower level for automobile and light rail traffic and its upper level for pedestrian and bicycle traffic (predominantly students at

6068-734: The same year, has the span of 90 m (295 ft) and crosses the valley of the Syrabach River. The difference between the two is that the Solkan Bridge was built from stone blocks, whereas the Friedensbrücke was built from a mixture of crushed stone and cement mortar. The world's largest arch bridge is the Chaotianmen Bridge over the Yangtze River with a length of 1,741 m (5,712 ft) and

6150-653: The simplest and oldest type of bridge in use today, and are a popular type. Some cantilever bridges also have a smaller beam connecting the two cantilevers, for extra strength. The largest cantilever bridge is the 549-metre (1,801 ft) Quebec Bridge in Quebec, Canada. With the span of 220 metres (720 ft), the Solkan Bridge over the Soča River at Solkan in Slovenia is the second-largest stone bridge in

6232-748: The undertimbers of bridges all around the world are spots of prevalent graffiti. Some bridges attract people attempting suicide, and become known as suicide bridges . The materials used to build the structure are also used to categorize bridges. Until the end of the 18th century, bridges were made out of timber, stone and masonry. Modern bridges are currently built in concrete, steel, fiber reinforced polymers (FRP), stainless steel or combinations of those materials. Living bridges have been constructed of live plants such as Ficus elastica tree roots in India and wisteria vines in Japan. Unlike buildings whose design

6314-547: The use of funds, particularly regarding using previously restricted highway funds for transit development, improved " intermodal " connections, and emphasized upgrades to existing facilities over building new capacity—particularly roadway capacity. To accomplish more serious metropolitan planning, ISTEA doubled federal funding for MPO operations and required the agencies to evaluate a variety of multimodal solutions to roadway congestion and other transportation problems. MPOs also were required to broaden public participation in

6396-433: The weld transitions . This results in a potential high benefit, using existing bridges far beyond the planned lifetime. While the response of a bridge to the applied loading is well understood, the applied traffic loading itself is still the subject of research. This is a statistical problem as loading is highly variable, particularly for road bridges. Load Effects in bridges (stresses, bending moments) are designed for using

6478-452: The world and the longest railroad stone bridge. It was completed in 1905. Its arch, which was constructed from over 5,000 tonnes (4,900 long tons; 5,500 short tons) of stone blocks in just 18 days, is the second-largest stone arch in the world, surpassed only by the Friedensbrücke (Syratalviadukt) in Plauen , and the largest railroad stone arch. The arch of the Friedensbrücke, which was built in

6560-877: Was estimated to be over 4.2 million as of April 2019. In 1956 the four counties of the Puget Sound region established the Puget Sound Regional Planning Conference, which changed its name to the Puget Sound Governmental Conference (PSGC) in 1958. It launched the Puget Sound Regional Transportation Study (PSRTS) in 1962 with support from the Washington State Highway Commission, the U.S. Bureau of Public Roads (predecessor of

6642-769: Was prepared in 2006–2007 to evaluate the potential of an eastside rail corridor for public use by an advisory committee working with HDR Engineering, a consultancy, with grants from the Federal Transit Administration , the Federal Highway Administration , and the Washington State Department of Transportation . It recommended replacing most of the Woodinville Subdivision rail line that runs through Seattle's eastern suburbs with

6724-690: Was visible in India by about the 4th century. A number of bridges, both for military and commercial purposes, were constructed by the Mughal administration in India. Although large bridges of wooden construction existed in China at the time of the Warring States period , the oldest surviving stone bridge in China is the Zhaozhou Bridge , built from 595 to 605 AD during the Sui dynasty . This bridge

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