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92-431: Town and Howe truss designs were patented by Ithiel Town in 1820 and William Howe in 1840, respectively. The Rexleigh Bridge employs "the patented Howe truss, with paired diagonal timbers, single timber counters, and multiple vertical iron rods defining each truss panel. The diagonals and verticals are connected to the upper and lower chords by means of cast-iron bearing blocks." Those bearing blocks are "embossed with

184-436: A live load to dead load ratio of 2-to-1. If this ratio is 2-to-1 or greater, then a six-panel truss must have counter-braces and these must at least one-third as strong as the braces. The counter-braces in an eight-panel truss must be at least two-thirds as strong as the braces, and the counter-braces in a 10-panel truss must be at least equal in strength to the braces. If rapidly moving live loads of any ratio are expected on

276-612: A brace, connected from the top of the last vertical post to the end of the lower chord. Struts are used to connect the two parallels of the chords to prevent lateral bending and reduce vibration. Two diagonals, connecting to the top of the vertical posts, are used. One of the diagonals should be a single piece, while the other is framed into the first piece or made of two pieces connected to it. X-braces, usually made of slender metal rods with threaded ends, are installed between vertical posts to help reduce sway . Knee braces, usually flat bars with eyelets on either end, are used to connect

368-424: A bridge of six panels or less (about 75 feet (23 m) long) needs no counter-bracing. An eight-panel truss requires counter-braces in every panel but the end panels, and these should be at least one-fourth as strong as the braces. A 10-panel truss requires counter-braces in every panel but the end panels, and these should be at least one-half as strong as the braces. A Howe truss bridge can be strengthened to achieve

460-531: A combination of wood and iron, or all iron. Whichever design is used, wooden timbers should have square ends without mortise and tenons . The design of an all-metal Howe truss follows that of the wooden truss. The parallels in each chord are usually built up out of smaller beams, each small beam fastened to one another to create a continuous beam. In wooden Howe trusses, these slender beams are usually no more than 10 to 15 inches (250 to 380 mm) wide and 6 to 8 inches (150 to 200 mm) deep. In iron trusses,

552-544: A group south where they founded Providence Plantations , which grew into the Colony of Rhode Island and Providence Plantations in 1636. At this time, Vermont was uncolonized, and the territories of New Hampshire and Maine were claimed and governed by Massachusetts. As the region grew, it received many immigrants from Europe due to its religious tolerance and economy. Relationships alternated between peace and armed skirmishes between colonists and local Native American tribes,

644-416: A hole may be drilled in the lug and brace/counter-brace and a dowel inserted to hold the beam in place. Iron angle blocks should have a hole cast in the upper lugs so that a bolt may pass through the lug and brace/counter-brace, securing the braces in place. The lower lugs in an angle block also have holes cast in them, to permit the angle block to be bolted to the chord. Two or more holes are cast through

736-407: A level of redundancy which allows it to withstand excessive loading (such as the loss of a panel due to collision). Prestressing is critical to the proper function of a Howe truss. During its initial construction, the diagonals are connected only loosely to the joints, and rely on prestressing, done at a later stage, to perform correctly. Moreover, diagonals in tension can only withstand stress below

828-424: A parallel in a chord are separated along their long side by a space equal to the diameter of the vertical posts, usually about 1 inch (25 mm). This allows the vertical posts to pass through the parallel in the chord. Batten plates are placed diagonally between the members of a chord, and nailed in place to reduce bending and to act as a shim to provide ventilation between chord members. The middle third of

920-540: A part of Massachusetts, but it was granted statehood on March 15, 1820, as part of the Missouri Compromise . Today, New England is defined as the six states of Maine, Vermont, New Hampshire, Massachusetts, Rhode Island, and Connecticut. New England's economic growth relied heavily on trade with the British Empire , and the region's merchants and politicians strongly opposed trade restrictions. As

1012-491: A second Howe truss design in 1846. The Howe truss bridge consists of an upper and lower "chord", each chord consisting of two parallel beams and each chord parallel to one another. The web consists of verticals, braces, and counter-braces. Vertical posts connect the upper and lower chords to one another, and create "panels". A diagonal brace in each panel strengthens the bridge, and a diagonal counter-brace in each panel enhances this strength. Howe truss bridges may be all wood,

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1104-512: A steady pace from the 1840s until cut off by World War I . The largest numbers came from Ireland and Britain before 1890, and after that from Quebec, Italy, and Southern Europe. The immigrants filled the ranks of factory workers, craftsmen, and unskilled laborers. The Irish and Italians assumed a larger and larger role in the Democratic Party in the cities and statewide, while the rural areas remained Republican. The Great Depression in

1196-522: A surge in iron bridge building occurred throughout the United States. The most commonly used designs were the Howe truss, Pratt truss, Bollman truss , Fink truss , and Warren truss . The Howe and Pratt trusses found favor because they used far fewer members. The 1962 built, World's Longest, Single Span, Wooden Covered Bridge at Bridgeport State Park, California, uses a Burr-Arch in combination with

1288-402: A third of its industrial workforce. It was also the most literate and most educated region in the country. During the same period, New England and areas settled by New Englanders (upstate New York, Ohio's Western Reserve , and the upper midwestern states of Michigan and Wisconsin ) were the center of the strongest abolitionist and anti-slavery movements in the United States, coinciding with

1380-649: A variety of the Eastern Algonquian languages . Prominent tribes included the Abenakis , Mi'kmaq , Penobscot , Pequots , Mohegans , Narragansetts , Nipmucs , Pocumtucks , and Wampanoags . Prior to the arrival of European colonists, the Western Abenakis inhabited what is now New Hampshire, New York, and Vermont, as well as parts of Quebec and western Maine. Their principal town was Norridgewock in today's Maine. The Penobscots lived along

1472-545: Is a better predictor than general forest age or biomass. Due to an increasing the amount of nitrogen in the soil from climate change , the red maple is becoming one of the most abundant trees in the region, and outcompeting other maples such as the sugar maple . The most populous cities as of the 2020 U.S. Census were (metropolitan areas in parentheses): During the 20th century, urban expansion in regions surrounding New York City has become an important economic influence on neighboring Connecticut, parts of which belong to

1564-495: Is avoided in order to avoid buckling. In practice, most wood stringers are 16 inches (410 mm) in width due to limitations in milling. There are usually six stringers in a bridge. Building the deck for a railroad bridge requires that a stringer lie directly beneath each rail, and that a stringer support each end of the railroad ties . Ties are usually 6 by 8 inches (150 by 200 mm) in cross-section, and 9 to 12 feet (2.7 to 3.7 m) in length. They are set directly on top of

1656-693: Is dotted with lakes, hills, marshes and wetlands, and sandy beaches. Important valleys in the region include the Champlain Valley , the Connecticut River Valley and the Merrimack Valley . The longest river is the Connecticut River , which flows from northeastern New Hampshire for 407 mi (655 km), emptying into Long Island Sound , roughly bisecting the region. Lake Champlain , which forms part of

1748-924: Is geologically a part of the New England province , an exotic terrane region consisting of the Appalachian Mountains , the New England highlands and the seaboard lowlands. The Appalachian Mountains roughly follow the border between New England and New York. The Berkshires in Massachusetts and Connecticut, and the Green Mountains in Vermont, as well as the Taconic Mountains , form a spine of Precambrian rock. The Appalachians extend northwards into New Hampshire as

1840-501: Is less snowfall (especially in the coastal areas where it is often warmer). Southern and coastal Connecticut is the broad transition zone from the cold continental climates of the north to the milder subtropical climates to the south. The frost free season is greater than 180 days across far southern/coastal Connecticut, coastal Rhode Island, and the islands (Nantucket and Martha's Vineyard). Winters also tend to be much sunnier in southern Connecticut and southern Rhode Island compared to

1932-536: Is listed on the National Register of Historic Places , is a stub . You can help Misplaced Pages by expanding it . This article about a bridge in New York is a stub . You can help Misplaced Pages by expanding it . Howe truss A Howe truss is a truss bridge consisting of chords, verticals, and diagonals whose vertical members are in tension and whose diagonal members are in compression. The Howe truss

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2024-418: Is one of the U.S. Census Bureau's nine regional divisions and the only multi-state region with clear and consistent boundaries. It maintains a strong sense of cultural identity, although the terms of this identity are often contrasted, combining Puritanism with liberalism, agrarian life with industry, and isolation with immigration. The earliest known inhabitants of New England were American Indians who spoke

2116-435: Is only the 39th-largest state, slightly smaller than Indiana . The remaining states are among the smallest in the U.S., including the smallest state —Rhode Island. The areas of the states (including water area) are: New England's long rolling hills, mountains, and jagged coastline are glacial landforms resulting from the retreat of ice sheets approximately 18,000 years ago, during the last glacial period . New England

2208-407: Is used to secure the vertical post to the chord. Special plates or washers of wood or metal are used to help distribute the stress induced by the vertical post onto the chords. Vertical posts are in tension, which is induced by tightening the nuts on the vertical bars. Braces are diagonal beams which connect the bottom of a vertical post to the top of the next vertical post. They are placed in

2300-420: Is very high technology manufacturing, such as jet engines, nuclear submarines, pharmaceuticals, robotics, scientific instruments, and medical devices. The Massachusetts Institute of Technology invented the format for university-industry relations in high tech fields and spawned many software and hardware firms, some of which grew rapidly. By the 21st century, the region had become famous for its leadership roles in

2392-545: Is widely used in wood buildings, particularly in providing roof support. New England New England is a region comprising six states in the Northeastern United States : Connecticut , Maine , Massachusetts , New Hampshire , Rhode Island , and Vermont . It is bordered by the state of New York to the west and by the Canadian provinces of New Brunswick to the northeast and Quebec to

2484-464: The Dominion of New England , an administrative union including all of the New England colonies. In 1688, the former Dutch colonies of New York , East New Jersey , and West New Jersey were added to the dominion. The union was imposed from the outside and contrary to the rooted democratic tradition of the colonies, and it was highly unpopular among the colonists. The dominion significantly modified

2576-558: The Mayflower Compact before leaving the ship, and it became their first governing document. The Massachusetts Bay Colony came to dominate the area and was established by royal charter in 1629 with its major town and port of Boston established in 1630. Massachusetts Puritans began to establish themselves in Connecticut as early as 1633. Roger Williams was banished from Massachusetts for theological reasons; he led

2668-689: The National Register of Historic Places in one multiple property submission. The others are the Buskirk Bridge , the Eagleville Bridge , and Shushan Bridge . All four were listed on the National Register of Historic Places on March 8, 1972. [REDACTED] Media related to Rexleigh Bridge at Wikimedia Commons This article about a historic property or district in Washington County , New York , that

2760-604: The New Deal coalition and making the once-Republican region into one that was closely divided. However, the enormous spending on munitions, ships, electronics, and uniforms during World War II caused a burst of prosperity in every sector. The region lost most of its factories starting with the loss of textiles in the 1930s and getting worse after 1960. The New England economy was radically transformed after World War II. The factory economy practically disappeared. Once-bustling New England communities fell into economic decay following

2852-877: The Penobscot River in Maine. The Narragansetts and smaller tribes under their sovereignty lived in Rhode Island, west of Narragansett Bay, including Block Island . The Wampanoags occupied southeastern Massachusetts, Rhode Island, and the islands of Martha's Vineyard and Nantucket . The Pocumtucks lived in Western Massachusetts, and the Mohegan and Pequot tribes lived in Connecticut. The Connecticut River Valley linked numerous tribes culturally, linguistically, and politically. As early as 1600 CE, French, Dutch, and English traders began exploring

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2944-574: The Puritan work ethic , in contrast to the Southern colonies which focused on agricultural production while importing finished goods from England. By 1686, King James II had become concerned about the increasingly independent ways of the colonies, including their self-governing charters, their open flouting of the Navigation Acts , and their growing military power. He therefore established

3036-668: The Securities Exchange Act of 1934 with his war on "unlisted securities". Hull gave testimony to the US Senate (Sen. Duncan Upshaw Fletcher ) for work on the Pecora Commission , which revealed that neither Albert H. Wiggin (born in Medfield, MA) nor J. P. Morgan Jr. had paid any income taxes in 1931 and 1932; a public outcry ensued. Boston figured prominently on the subject of securities laws in

3128-634: The Siege of Boston by continental troops. In March 1776, British forces were compelled to retreat from Boston. After the dissolution of the Dominion of New England, the colonies of New England ceased to function as a unified political unit but remained a defined cultural region. There were often disputes over territorial jurisdiction, leading to land exchanges such as those regarding the Equivalent Lands and New Hampshire Grants . By 1784, all of

3220-619: The White Mountains , and then into Maine and Canada. Mount Washington in New Hampshire is the highest peak in the Northeast, although it is not among the ten highest peaks in the eastern United States. It is the site of the second highest recorded wind speed on Earth, and has the reputation of having the world's most severe weather. The coast of the region, extending from southwestern Connecticut to northeastern Maine,

3312-647: The 1850s, and all of New England became strongly Republican, including areas that had previously been strongholds for both the Whig and the Democratic parties. New England remained solidly Republican until Catholics began to mobilize behind the Democrats, especially in 1928. This led to the end of "Yankee Republicanism" and began New England's relatively swift transition into a consistently Democratic stronghold in national elections. The flow of immigrants continued at

3404-585: The Beverly Cotton Manufactory. The Connecticut River Valley became a crucible for industrial innovation, particularly the Springfield Armory , pioneering such advances as interchangeable parts and the assembly line which influenced manufacturing processes all around the world. From early in the nineteenth century until the mid-twentieth, the region surrounding Springfield, Massachusetts and Hartford, Connecticut served as

3496-591: The Howe truss to be the best form of wooden truss bridge, and believed it to be the most commonly used truss bridge in the United States at that time. All-iron Howe trusses began to be built about 1845. Examples include a 50-foot (15 m) long iron Howe truss was built for the Boston and Providence Railroad and a 30-foot (9.1 m) long railroad bridge over the Ohio and Erie Canal in Cleveland. Iron, however,

3588-419: The Howe truss, the counter-braces used in the center panel should be equal in strength to the braces, and the panel next to the end panel should have counter-braces at least one-half as strong as the braces. Where diagonal braces and counter-braces meet, they are usually bolted together. Braces and counter-braces are held in place with angle blocks. Angle blocks are triangular in cross-section and should be

3680-501: The Howe-Truss to achieve this over 210' span. The only maintenance a Howe truss requires is adjustment of the nuts on the vertical posts to equalize strain. The diagonals in a wooden Pratt truss proved difficult to keep in proper adjustment, so the Howe truss became the preferred design for a wooden bridge or for a "transitional" bridge of wood with iron verticals. Engineering professor Horace R. Thayer, writing in 1913, considered

3772-828: The New World, trading metal, glass, and cloth for local beaver pelts. On April 10, 1606, King James I of England issued a charter for the Virginia Company , which consisted of the London Company and the Plymouth Company . These two privately funded ventures were intended to claim land for England, to conduct trade, and to return a profit. In 1620, the Pilgrims arrived on the Mayflower and established Plymouth Colony in Massachusetts, beginning

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3864-820: The Pratt and Howe trusses spurred Benjamin Henry Latrobe II , chief engineer of the Baltimore and Ohio Railroad , to build large numbers of iron bridges. After two famous iron bridge collapses (one in the United States, the other in the United Kingdom ), few of these were built in the North . This meant most iron bridges erected prior to the American Civil War were located in the South . About 1867,

3956-489: The Protestant Great Awakening in the region. Abolitionists who demanded immediate emancipation had their base in the region, such as William Lloyd Garrison , John Greenleaf Whittier , and Wendell Phillips . So too did anti-slavery politicians who wanted to limit the growth of slavery, such as John Quincy Adams , Charles Sumner , and John P. Hale . The anti-slavery Republican Party was formed in

4048-622: The United States of the 1930s hit the region hard, with high unemployment in the industrial cities. The Boston Stock Exchange rivaled the New York Stock Exchange in 1930. In the beginning of 1930 John C. Hull , first Securities Director of Massachusetts (1930–1936), helped to mitigate the consequences of the Wall Street Crash of 1929 and the Great Depression. He was helpful in the passing of

4140-671: The United States and the United Kingdom fought the War of 1812 , New England Federalists organized the Hartford Convention in the winter of 1814 to discuss the region's grievances concerning the war, and to propose changes to the United States Constitution to protect the region's interests and maintain its political power. Radical delegates within the convention proposed the region's secession from

4232-418: The United States' epicenter for advanced manufacturing, drawing skilled workers from all over the world. The rapid growth of textile manufacturing in New England between 1815 and 1860 caused a shortage of workers. Recruiters were hired by mill agents to bring young women and children from the countryside to work in the factories. Between 1830 and 1860, thousands of farm girls moved from rural areas where there

4324-560: The United States, but they were outnumbered by moderates who opposed the idea. Politically, the region often disagreed with the rest of the country. Massachusetts and Connecticut were among the last refuges of the Federalist Party , and New England became the strongest bastion of the new Whig Party when the Second Party System began in the 1830s. The Whigs were usually dominant throughout New England, except in

4416-412: The angle block. The upper lug may be a single flange that fits into a groove cut into the surface of the diagonal, or there may be two to four lugs which form an opening into which the brace and counter-brace are seated. The diagonals are kept in place by tightening the nuts on the vertical posts. Cleats can be nailed to a wooden angle block to help keep braces and counter-braces seated. Alternatively,

4508-743: The appointment of the governors. After the Glorious Revolution , in 1689, Bostonians overthrew the royal governor, Sir Edmund Andros . During a popular and bloodless uprising , they seized dominion officials and adherents to the Church of England . These tensions eventually culminated in the American Revolution , boiling over with the outbreak of the War of American Independence in 1775. The first battles of which were fought in Lexington and Concord, Massachusetts , leading to

4600-401: The beams of the upper chord to one another. In the lower chord of a wooden bridge, clamps are used to couple beams together. Although generally of the same length, beams are positioned so that a splice (the point where the end of two beams meet) is near the point where two panels meet but not adjacent to the splice in an adjacent pair of beams. The individual small beams which make up

4692-628: The bloodiest of which was the Pequot War in 1637 which resulted in the Mystic massacre . On May 19, 1643, the colonies of Massachusetts Bay, Plymouth, New Haven , and Connecticut joined in a loose compact called the New England Confederation (officially "The United Colonies of New England"). The confederation was designed largely to coordinate mutual defense, and it gained some importance during King Philip's War which pitted

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4784-489: The border between Vermont and New York, is the largest lake in the region, followed by Moosehead Lake in Maine and Lake Winnipesaukee in New Hampshire. The climate of New England varies greatly across its 500 miles (800 km) span from northern Maine to southern Connecticut: Maine, New Hampshire, Vermont, and western Massachusetts have a humid continental climate (Dfb in Köppen climate classification ). In this region

4876-423: The center of the angle block, to allow the vertical posts to pass through and be anchored on the other side of the chord. End panels are the four panels on either side of the end of a Howe truss bridge. These should be the same height as the chords, but not more. The upper chord does not extend past the portal (the space formed by the last four vertical posts at either end of the bridge). The end panels need only

4968-451: The charters of the colonies, including the appointment of royal governors to nearly all of them. There was an uneasy tension among the royal governors, their officers, and the elected governing bodies of the colonies. The governors wanted unlimited authority, and the different layers of locally elected officials would often resist them. In most cases, the local town governments continued operating as self-governing bodies, just as they had before

5060-474: The coast, which enabled numerous cities to take advantage of water power along the many rivers, such as the Connecticut River , which bisects the region from north to south. Each state is generally subdivided into small municipalities known as towns , many of which are governed by town meetings . Unincorporated areas are practically nonexistent outside of Maine, and village-style governments common in other areas are limited to Vermont and Connecticut. New England

5152-518: The colonists and their Indian allies against a widespread Indian uprising from June 1675 through April 1678, resulting in killings and massacres on both sides. In the aftermath of settler-Native conflicts, hundreds of captive Indians were sold into slavery . Up until 1700, Native Americans comprised a majority of the non-white labor force in colonial New England. During the next 74 years, there were six colonial wars that took place primarily between New England and New France , during which New England

5244-509: The construction site, and sometimes even entire trusses could be manufactured and assembled off-site and transported by rail to the intended location. Some sort of falsework , usually in the form of a trestle , is required to erect the bridge. The development of the Pratt and Howe trusses spurred the construction of iron bridges in the United States. Until 1850, few iron bridges in the country were longer than 50 feet (15 m). The simple design, ease of manufacture, and ease of construction of

5336-574: The early 1930s in response to the Great Depression. Harvard University professors Felix Frankfurter , Benjamin V. Cohen , and James M. Landis drafted the Securities Act of 1933 and the Securities Exchange Act of 1934. Joseph P. Kennedy Sr. was the first chairman of the U.S. Securities and Exchange Commission , and he was from Boston. The Democrats appealed to factory workers and especially Catholics, pulling them into

5428-425: The end of the bridge suffer the highest amount of stress. The stress affecting counter-braces depends on the ratio of live load to dead load per unit of length, and how the live load is distributed across the bridge. A uniform distribution of live load will put no stress on the counter-braces, while putting live load on only a portion of the bridge will create maximum stress on the center counter-braces. Because of

5520-466: The fields of education, medicine, medical research, high-technology, finance, and tourism. Some industrial areas were slow in adjusting to the new service economy. In 2000, New England had two of the ten poorest cities in the U.S. (by percentage living below the poverty line): the state capitals of Providence, Rhode Island and Hartford, Connecticut . They were no longer in the bottom ten by 2010; Connecticut, Massachusetts, and New Hampshire remain among

5612-500: The flight of the region's industrial base. The textile mills one by one went out of business from the 1920s to the 1970s. For example, the Crompton Company went bankrupt in 1984 after 178 years in business, costing the jobs of 2,450 workers in five states. The major reasons were cheap imports, the strong dollar, declining exports, and a failure to diversify. The shoe industry subsequently left the region as well. What remains

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5704-556: The harbor. Britain responded with a series of punitive laws stripping Massachusetts of self-government which the colonists called the " Intolerable Acts ". These confrontations led to the first battles of the American Revolutionary War in 1775 and the expulsion of the British authorities from the region in spring 1776. The region played a prominent role in the movement to abolish slavery in the United States, and it

5796-556: The history of permanent European colonization in New England. In 1616, English explorer John Smith named the region "New England". The name was officially sanctioned on November 3, 1620, when the charter of the Virginia Company of Plymouth was replaced by a royal charter for the Plymouth Council for New England , a joint-stock company established to colonize and govern the region. The Pilgrims wrote and signed

5888-610: The largest city in New Hampshire; and Providence, Rhode Island , the capital of and largest city in Rhode Island. In 1620, the Pilgrims established Plymouth Colony , the second successful settlement in British America after the Jamestown Settlement in Virginia , founded in 1607. Ten years later, Puritans established Massachusetts Bay Colony north of Plymouth Colony. Over the next 126 years, people in

5980-403: The last strut and last vertical posts on both ends of the bridge. Individual panels may be prefabricated off-site. When panels are connected to one another on-site, shims are used to pack any spaces and bolted in place. Floor beams extend between the parallels of a chord and are used to support the stringers and decking. Floor beams may sit atop the chord below them, or they may be hung from

6072-425: The lower chord is always reinforced by one or more beams bolted to the chord. This reinforcement is generally one-sixth the width of the cross-section of the lower chord. If a wood chord needs to be strengthened even more, additional slender beams may be bolted to the middle third of the each side of the lower chord. When construction is complete, the upper chord of a Howe truss bridge will be in compression , while

6164-414: The lower chord is in tension . Vertical posts connect the upper and lower chords, and divide the truss into panels. The Howe truss usually uses iron or steel verticals. These are straight and round, slightly reduced in circumference at the ends, and a screw thread added. The vertical usually passes through the center of the angle block and then through space left in the upper and lower chord. A nut

6256-426: The more Democratic Maine and New Hampshire. New England was key to the Industrial Revolution in the United States. The Blackstone Valley running through Massachusetts and Rhode Island has been called the birthplace of America's industrial revolution. In 1787, the first cotton mill in America was founded in the North Shore seaport of Beverly, Massachusetts as the Beverly Cotton Manufactory . The Manufactory

6348-417: The name of their manufacturer, 'R. Comins, Troy, N.Y.,'" and, although the timber used is local, the bridge "appears to be a rare surviving example of this type of prefabricated nineteenth-century bridge construction." It was individually inventoried by the New York State Office of Parks, Recreation and Historic Preservation in 1977. It is one of four Washington County covered bridges submitted for listing in

6440-414: The north. The Gulf of Maine and Atlantic Ocean are to the east and southeast, and Long Island Sound is to the southwest. Boston is New England's largest city and the capital of Massachusetts. Greater Boston is the largest metropolitan area, with nearly a third of New England's population; this area includes Worcester, Massachusetts , the second-largest city in New England; Manchester, New Hampshire ,

6532-424: The prestressing level. (The size of the member does not matter due to the loose fitting of the diagonal to the joint.) Proper prestressing during construction is therefore critical in the correct performance of the bridge. Maximum stress is placed on the center of the chords when a live load reaches the center of the bridge, or when the live load extends the length of the bridge. Both the vertical posts and braces at

6624-583: The region fought in four French and Indian Wars until the English colonists and their Iroquois allies defeated the French and their Algonquian allies. In the late 18th century, political leaders from the New England colonies initiated resistance to Britain's taxes without the consent of the colonists . Residents of Rhode Island captured and burned a British ship which was enforcing unpopular trade restrictions, and residents of Boston threw British tea into

6716-628: The rest of New England. New England contains forested ecosystems with a variety of terrestrial vertebrates. Land-use patterns and land disturbance, such as the dramatic increase in land clearing for agriculture in the mid eighteenth century to nineteenth century, greatly altered the ecosystem and resulted in extinctions, local extirpations , and recolonizations. According to an analysis of USDA Forest Service data, tree species diversity increases from north to south at about two to three species per degree in latitude. In addition, taller trees are associated with higher tree species diversity, and tree height

6808-442: The same height and width as the parallel of the chord. Angle blocks may be made of wood or iron, although iron is usually used for permanent structures. Angle blocks are attached upside down to the upper chord, and right side up to the lower chord. Angle blocks have lugs— flanges or projections used for carrying, seating, or supporting something. The ends of the braces and counter-braces should cut or cast to rest squarely against

6900-469: The same plane as the chord. Unlike iron or steel braces which are built up, wooden braces are cut to length. Where the parallel in a chord has a thickness of X number of beams, each brace should have a thickness of X minus 1 beams. The depth-to-width ratio of each member of a diagonal brace should be no greater than that of the brace as a whole. Braces may be a single piece, or several pieces spliced together with fishplate. Braces are in compression due to

6992-406: The states in the region had taken steps towards the abolition of slavery, with Vermont and Massachusetts introducing total abolition in 1777 and 1783, respectively. The nickname "Yankeeland" was sometimes used to denote the New England area, especially among Southerners and the British. Vermont was admitted to statehood in 1791 after settling a dispute with New York. The territory of Maine had been

7084-487: The stress placed on the bridge, the Howe truss is suitable for spans 150 feet (46 m) in length or less. No provision is made in a Howe truss for expansion or contraction due to changes in temperature. The Howe truss was highly economical due to its ease of construction. The wooden pieces can be designed using little but a steel square and scratch awl , and the truss can be framed using only an adze , auger , and saw . Panels could be prefabricated and transported to

7176-404: The stringers, about 12 inches (300 mm) apart. Guard rails 6 by 8 inches (150 by 200 mm) in cross-section are set 20 inches (510 mm) from the center of the ties, and bolted to every third tie. The inner truss of a Howe truss is statically indeterminate . There are two paths for stress during loading, a pair of diagonals in compression and a pair in tension. This gives the Howe truss

7268-414: The ten wealthiest states in the United States in terms of median household income and per capita income. The states of New England have a combined area, including water surfaces, of 71,988 square miles (186,447 km ), making the region slightly larger than the state of Washington and slightly smaller than Great Britain . Maine alone constitutes nearly one-half of the total area of New England, yet

7360-415: The tightening of the nuts on the verticals. Counter-braces are diagonal beams which connect the bottom of a vertical post to the top of the next vertical post, and run roughly perpendicular to braces. They are placed in the same plane as the chord, are generally uniform in size, and should have a thickness one beam less than a brace. Unlike braces, counter-braces are a single piece. Generally speaking,

7452-503: The upper chord beams are the same length as the panel. Upper chord beams are usually made of cast iron , while the lower chord beams are of wrought iron . A minimum of three small beams are used, each uniform in width and depth. Fishplates are usually used to splice beams together. (Lower chord beams may have eyes on each end, in which case they are fastened together with bolts, pins , or rivets .) In wooden trusses, cotters and iron bolts are used every 4 feet (1.2 m) to connect

7544-449: The vertical posts. Floor beams generally have the greatest depth of any beam in the bridge. Floor beams are usually placed where two panels meet. If they are placed somewhere mid-panel, the chord must be reinforced to resist bending , buckling , and shear stress . Stringers are beams set on top of the floor beams, parallel to the chords. A stringer may have a depth-to-width ratio anywhere from 2-to-1 to 6-to-1. A ratio greater than 6-to-1

7636-452: The winters are long and cold, and heavy snow is common (most locations receive 60–120 inches (150–300 cm) of snow annually in this region). The summer's months are moderately warm, though summer is rather short and rainfall is spread through the year. In central and eastern Massachusetts, northern Rhode Island, and northern Connecticut, the same humid continental prevails (Dfa), though summers are warm to hot, winters are shorter, and there

7728-464: Was 180 feet (55 m) in length. Both bridges were erected in 1840. One of Howe's workmen, Amasa Stone , purchased for $ 40,000 ($ 1,220,800 in 2023 dollars) in 1842 the rights to Howe's patented bridge design. With his financial backer, Azariah Boody, Stone formed the bridge-building firm of Boody, Stone & Co., which erected a large number of Howe truss bridges throughout New England . Howe made additional improvements to his bridge, and patented

7820-665: Was a construction contractor in Massachusetts when he patented the Howe truss design in 1840. That same year, he established the Howe Bridge Works to build bridges using his design. The first Howe truss ever built was a single-lane, 75-foot (23 m) long bridge in Connecticut carrying a road. The second was a railroad bridge over the Connecticut River in Springfield, Massachusetts . This bridge, which drew extensive praise and attention, had seven spans and

7912-851: Was allied with the Iroquois Confederacy and New France was allied with the Wabanaki Confederacy . Mainland Nova Scotia came under the control of New England after the Siege of Port Royal (1710) , but both New Brunswick and most of Maine remained contested territory between New England and New France. The British eventually defeated the French in 1763, opening the Connecticut River Valley for British settlement into western New Hampshire and Vermont. The New England Colonies were settled primarily by farmers who became relatively self-sufficient. Later, New England's economy began to focus on crafts and trade, aided by

8004-545: Was also considered the largest cotton mill of its time. Technological developments and achievements from the Manufactory led to the development of more advanced cotton mills, including Slater Mill in Pawtucket, Rhode Island . Towns such as Lawrence, Massachusetts , Lowell, Massachusetts , Woonsocket, Rhode Island , and Lewiston, Maine became centers of the textile industry following the innovations at Slater Mill and

8096-419: Was becoming essential now that heavy railroad trains were using bridges. In 1830, Stephen Harriman Long received a patent for an all-wood parallel chord truss bridge. Long's bridge contained diagonal braces which were prestressed with wedges. The Long truss did not require a connection between the diagonal and the truss, and was able to remain in compression even when the wood shrank somewhat. William Howe

8188-800: Was invented by William Howe in 1840, and was widely used as a bridge in the mid to late 1800s. The earliest bridges in North America were made of wood, which was abundant and cheaper than stone or masonry. Early wooden bridges were usually of the Towne lattice truss or Burr truss design. Some later bridges were McCallum trusses (a modification of the Burr truss). About 1840, iron rods were added to wooden bridges. The Pratt truss used wooden vertical members in compression with diagonal iron braces. The Howe truss used iron vertical rods in tension with wooden diagonal braces. Both trusses used counter-bracing, which

8280-486: Was no paid employment to work in the nearby mills, such as the Lowell Mill Girls . As the textile industry grew, immigration also grew. By the 1850s, immigrants began working in the mills, especially French Canadians and Irish . New England as a whole was the most industrialized part of the United States. By 1850, the region accounted for well over a quarter of all manufacturing value in the country and over

8372-578: Was the first region of the U.S. transformed by the Industrial Revolution , initially centered on the Blackstone and Merrimack river valleys. The physical geography of New England is diverse. Southeastern New England is covered by a narrow coastal plain , while the western and northern regions are dominated by the rolling hills and worn-down peaks of the northern end of the Appalachian Mountains . The Atlantic fall line lies close to

8464-608: Was the preferred bridge for automobile and railroads, and the Howe truss did not adapt well to all-iron construction. The Pratt truss' single diagonal bracing system meant less cost, and its ability to use wrought-iron stringers under railroad rails and ties, led bridge builders to favor the Pratt over the Howe. Heavier live loads, particularly by railroads, led bridge builders to favor plate girder and Towne lattice bridges for spans less than 60 feet (18 m), and Warren girder bridges for all other spans. Trusses have been widely used in architecture since ancient times. The Howe truss

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