A truss is an assembly of members such as beams , connected by nodes , that creates a rigid structure.
90-610: The Royal Alexandra Interprovincial Bridge , also known as the Alexandra Bridge or Interprovincial Bridge , is a steel truss cantilever bridge spanning the Ottawa River between Ottawa , Ontario and Gatineau , Quebec . In addition to carrying vehicle traffic, a shared use pathway on the bridge for pedestrians and cyclists is maintained by the National Capital Commission . The bridge
180-444: A cruck frame or a couple of rafters. One engineering definition is: "A truss is a single plane framework of individual structural member [sic] connected at their ends of forms a series of triangle [sic] to span a large distance". A truss consists of typically (but not necessarily) straight members connected at joints, traditionally termed panel points . Trusses are typically (but not necessarily ) composed of triangles because of
270-412: A lattice . The Vierendeel truss is a structure where the members are not triangulated but form rectangular openings, and is a frame with fixed joints that are capable of transferring and resisting bending moments . As such, it does not fit the strict definition of a truss (since it contains non-two-force members): regular trusses comprise members that are commonly assumed to have pinned joints, with
360-476: A ceiling joist , and in other mechanical structures such as bicycles and aircraft. Because of the stability of this shape and the methods of analysis used to calculate the forces within it, a truss composed entirely of triangles is known as a simple truss. However, a simple truss is often defined more restrictively by demanding that it can be constructed through successive addition of pairs of members, each connected to two existing joints and to each other to form
450-519: A lane for carriage traffic. A large fire severely damaged the bridge in 1946, permanently terminating trolley traffic. During the late 1950s the bridge was upgraded to carry vehicular and pedestrian traffic. The closure of Ottawa Union Station in 1966 saw the last passenger trains use the Royal Alexandra Bridge and the railway tracks were removed as the bridge became exclusively a vehicular-pedestrian bridge. On August 21, 1989,
540-403: A larger cross section than on a previous iteration requires giving other members a larger cross section as well, to hold the greater weight of the first member—one needs to go through another iteration to find exactly how much greater the other members need to be. Sometimes the designer goes through several iterations of the design process to converge on the "right" cross section for each member. On
630-513: A linked city park system. This included formally establishing Gatineau Park . Most notably, the Report recommended a major political reform : the creation of a federal district and federal authority to exercise control over planning and development. The General Plan recommended extinguishing the Ottawa and Hull municipal governments. In their place, a Federal District Commission, similar to
720-402: A matrix method such as the direct stiffness method , the flexibility method , or the finite element method. Illustrated is a simple, statically determinate flat truss with 9 joints and (2 x 9) − 3 = 15 members. External loads are concentrated in the outer joints. Since this is a symmetrical truss with symmetrical vertical loads, the reactive forces at A and B are vertical, equal, and half
810-404: A new joint, and this definition does not require a simple truss to comprise only triangles. The traditional diamond-shape bicycle frame, which utilizes two conjoined triangles, is an example of a simple truss. A planar truss lies in a single plane . Planar trusses are typically used in parallel to form roofs and bridges. The depth of a truss, or the height between the upper and lower chords,
900-566: A truss are called 'top chords' and are typically in compression , the bottom beams are called 'bottom chords', and are typically in tension . The interior beams are called webs , and the areas inside the webs are called panels , or from graphic statics (see Cremona diagram ) 'polygons'. Truss derives from the Old French word trousse , from around 1200 AD, which means "collection of things bound together". The term truss has often been used to describe any assembly of members such as
990-619: A truss is a structure that "consists of two-force members only, where the members are organized so that the assemblage as a whole behaves as a single object". A "two-force member" is a structural component where force is applied to only two points. Although this rigorous definition allows the members to have any shape connected in any stable configuration, trusses typically comprise five or more triangular units constructed with straight members whose ends are connected at joints referred to as nodes . In this typical context, external forces and reactions to those forces are considered to act only at
SECTION 10
#17327903008221080-538: Is a 393 meter (1,291 foot) long truss bridge built in 1912. The structure is composed of nine Pratt truss spans of varying lengths. The bridge is still in use today. The Wright Flyer used a Pratt truss in its wing construction, as the minimization of compression member lengths allowed for lower aerodynamic drag . Named for their shape, bowstring trusses were first used for arched truss bridges , often confused with tied-arch bridges . Thousands of bowstring trusses were used during World War II for holding up
1170-422: Is a roof or floor truss whose wood members are connected with metal connector plates . Truss members form a series of equilateral triangles, alternating up and down. Truss members are made up of all equivalent equilateral triangles. The minimum composition is two regular tetrahedrons along with an octahedron. They fill up three dimensional space in a variety of configurations. [REDACTED] The Pratt truss
1260-673: Is paved while the east deck is a metal steel grating. The west deck provides a panorama of the Ottawa-Gatineau skyline, the Ottawa River and Parliament Buildings. That deck is used by rollerbladers , cyclists, and pedestrians, and is on the official route of the Trans Canada Trail . The bike lane of the bridge links to two major cross-town bike paths. In Gatineau, there is the Voyageur Pathway that links
1350-496: Is preferable to a braced-frame system, which would leave some areas obstructed by the diagonal braces. A truss that is assumed to comprise members that are connected by means of pin joints, and which is supported at both ends by means of hinged joints and rollers, is described as being statically determinate . Newton's Laws apply to the structure as a whole, as well as to each node or joint. In order for any node that may be subject to an external load or force to remain static in space,
1440-733: Is responsible for managing and maintaining several assets in the Capital Region. The NCC operates 90 kilometers of scenic parkways through Ottawa and NCC parks in Gatineau. The NCC operates several urban parks in Ottawa and Gatineau. The NCC is the steward of the Capital's six official residences: Other assets managed by the NCC are: The role of the NCC is to champion the interests of Ottawa , Gatineau , and surrounding region as
1530-464: Is similar to a king post truss in that the outer supports are angled towards the centre of the structure. The primary difference is the horizontal extension at the centre which relies on beam action to provide mechanical stability. This truss style is only suitable for relatively short spans. Lenticular trusses, patented in 1878 by William Douglas (although the Gaunless Bridge of 1823 was
1620-622: Is the Crown corporation responsible for development, urban planning , and conservation in Canada's Capital Region ( Ottawa , Ontario and Gatineau , Quebec ), including administering most lands and buildings owned by the Government of Canada in the region. The NCC is the capital's largest property owner, owning and managing over 11% of all lands in the Capital Region. It also owns over 1,600 properties in its real estate portfolio, including
1710-443: Is the Capital's largest property owner, owning and managing over 11% of all lands in the Capital Region. It also owns over 1,600 properties in its real estate portfolio, including the Capital's six official residences; commercial, residential and heritage buildings; and agricultural facilities. Over 70 NCC-managed buildings that are older than 40 years have been designated as "classified" or "recognized" federal heritage buildings by
1800-422: Is the force in the member, γ is a safety factor (typically 1.5 but depending on building codes ) and σ y is the yield tensile strength of the steel used. The members under compression also have to be designed to be safe against buckling. The weight of a truss member depends directly on its cross section—that weight partially determines how strong the other members of the truss need to be. Giving one member
1890-405: Is the simplest space truss, consisting of six members that meet at four joints. Large planar structures may be composed from tetrahedrons with common edges, and they are also employed in the base structures of large free-standing power line pylons. There are two basic types of truss: A combination of the two is a truncated truss, used in hip roof construction. A metal plate-connected wood truss
SECTION 20
#17327903008221980-465: Is what makes it an efficient structural form. A solid girder or beam of equal strength would have substantial weight and material cost as compared to a truss. For a given span , a deeper truss will require less material in the chords and greater material in the verticals and diagonals. An optimum depth of the truss will maximize the efficiency. A space frame truss is a three-dimensional framework of members pinned at their ends. A tetrahedron shape
2070-546: The 2006 elections , the Government of Canada asked for a formal review of the mandate of the NCC. A panel conducting the review, in its report, suggested that the NCC needed more money and should become more transparent . In 2018, the Government of Canada announced CA$ 55 million in funding to support critical repair and maintenance of NCC's major infrastructure assets. In 2020, the NCC secured $ 52.4 million in funding towards some of its most significant assets. The NCC
2160-567: The Canadian Tulip Festival and the Canada Day festivities. The bridge used to carry roughly 15,000 vehicles, 2000 pedestrians and 1300 cyclists each day, as of 2009. A two-year rehabilitation project which began in 2009, included various structural improvements and replacements of the centre concrete deck, the wood boardwalk and guardrails. Nepean Point overlooks the bridge from the Ottawa side. The Rideau Canal meets
2250-616: The Federal Heritage Buildings Review Office (FHBRO). The continuing preservation, evolution and management of Confederation Boulevard , the ceremonial route linking key attractions in National Capital Region, on both sides of the Ottawa River , in Ottawa as well as Gatineau, Quebec, are the responsibility of the NCC and its partners. These roles are in contrast with the mandates of the various municipal governments, which serve
2340-720: The Gréber Plan . Due to the Second World War , however, Gréber's plan was put on hold. At the conclusion of the War in 1945, an area of 2,330 km (580,000 acres) was declared the " National Capital District ," and the Federal District Commission Ac t was amended to expand the responsibilities of the FDC, giving it a truly national scope. Gréber was eventually invited back to develop his plan for
2430-539: The National Capital Act , the board consists of a chairperson , a chief executive officer (CEO), and 13 other members with relevant professional backgrounds from the Capital Region and across Canada. Since April 2016, the mayors of Ottawa and Gatineau have also ex officio held seats on the board, on a non-voting basis. The NCC holds an annual public meeting in which members of the public are able to express their ideas and ask questions directly to
2520-612: The National Capital Region was blemished and transformed by industrialization . According to then-Prime Minister Wilfrid Laurier , what became the City of Ottawa was "not a handsome city" by the 1880s. Laurier, together with Lady Aberdeen , the wife of the governor general , advanced the idea of planning for a better capital. </ref> In 1899, the Ottawa Improvement Commission ( OIC )
2610-552: The Ottawa River immediately upriver of the bridge's Ottawa abutment. In 2018 a cost analysis determined that replacing the bridge would be less disruptive and less expensive than maintaining it. The following year, the Canadian government directed the bridge to be replaced by the year 2029. As planning got underway, the bridge continued to be maintained for use by vehicle and pedestrian traffic. In October 2023, following an assessment that found severe deterioration due to corrosion of
2700-499: The Town Planning Institute of Canada , published a report (known as the "Cauchon Report") containing a new planning strategy for the Capital. The report included numerous studies on the Capital done by Cauchon over a period of around 16 years. It also proposed the reorganization of railway tracks , the building of highways, the development of parks and parkways, and the relocation of industrial activities. In 1927,
2790-486: The nation's capital , typically with regard to issues of national interest, such as the location of monument and museum sites, and major streetscapes such as Confederation Boulevard . The objects and purposes of the NCC are "to prepare plans for and assist in the development, conservation and improvement of the National Capital Region in order that the nature and character of the seat of the Government of Canada may be in accordance with its national significance." The NCC
Alexandra Bridge - Misplaced Pages Continue
2880-616: The 6 official residences in the Capital Region. The committee also provides advice to Public Services and Procurement Canada , who is responsible for the Citadel , i.e., the Governor General ’s official residence in Québec City . The committee consists of experts in interior design , architecture, heritage, and real estate development. It has 7 members, plus 1 board observer and 2 ex officio members (the NCC chairperson and
2970-626: The Aylmer and Gatineau sectors, while in Ottawa there is the Ottawa River Pathway's western section that links downtown to Carling Avenue. A third pathway, De l'Île, travels through the Old Hull section beside Boulevard des Allumettières (formerly called Boulevard Saint-Laurent), the road that continues after the bridge on the Gatineau side making a single stretch of road from Eardley Road to the former CFB Rockcliffe . At both ends of
3060-522: The CEO). Aside from the ex officio and observer members, committee members include: Marta Farevaag (chairperson), Bernard Serge Gagné (vice chairperson), Ken Greenberg, Hagit Hadaya, and Chris Piché . The Canadiana Fund solicits donations of heritage art, furniture, and funds to augment the staterooms of the official residences. Pieces that are chosen are meant to "reflect Canada's heritage, artistic traditions and historical associations," or they "complement
3150-508: The Capital, which was finally published in 1950. In 1958, Parliament passed the National Capital Act , which established the National Capital Region as well as a new National Capital Commission ( NCC ) to succeed the FDC as responsible for bringing Gréber's plan into reality. The replacement of the FDC came as result of it having repeatedly failed to convince municipal governments to cooperate in planning efforts regarding
3240-402: The FDC began to acquire land for Gatineau Park and, by 1939, a total of 6,500 hectares had been acquired. In 1936, Prime Minister William Lyon Mackenzie King invited French town planner Jacques Gréber to act as an advisor for planning in the Capital. A couple of years later, in 1938, Gréber was commissioned to develop a vision and plan for the National Capital Region, now famously known as
3330-702: The General Plan. The "Report of the Federal Plan Commission on a General Plan for the Cities of Ottawa and Hull," better known as the "Holt Report" or the "Bennett Plan," was released in January 1915 and was one of Canada's first comprehensive plans. The report recommended that the work of the OIC be broadened, expanding on the 1903 Todd Commission's beautification proposals for urban parkways and
3420-518: The Holt Commission). Todd was appointment chairmen when the Federal Plan Commission was established in 1913 by Order-In-Council of Prime Minister Robert Borden 's government with the purpose of "draw[ing] up and perfect[ing]" a comprehensive scheme for the future of the rapidly growing Federal Capital, called the "General Plan." The Commission was joined by a renowned architect and urban planner from Chicago, Edward H. Bennett , who prepared
3510-483: The NCC and 3 NCC employees—all of whom are those who have expertise and experience in matters related to the subject. These members are Anne Ménard (chairperson), Collinda Joseph (vice-chairperson), Yoland Charette, Catherine Gardner, Rita Tadi, Daryl Rock, and Monique Beaudoin. The NCC has built relationships with people and organizations throughout the Capital Region and across Canada, including local municipalities and Indigenous communities. To foster partnerships in
3600-543: The NCC chairperson and CEO, this committee includes: Maryse Gaudreault (Ex-Officio member), Vincent Asselin (Chairperson), Ken Greenberg, David L.A. Gordon, Bruce Haden, Anne-Marie Parent, Tobi Nussbaum (Ex-Officio member), Barry Padolsky, Beverly A. Sandalack, Collinda Joseph (observer), Caroline Lajoie (observer), and Andy Kikites (observer). The Advisory Committee on the Official Residences of Canada advises on asset management and matters that pertain to
3690-783: The NCC chairperson and the CEO (as ex officio members) sit on the Governance Committee. The Advisory Committee on Planning, Design and Realty advises on the long-range plans and policies for the use of public lands and properties in the Capital Region; design proposals affecting federal lands; and matters of real property . The committee consists of experts in real estate development ; environmental , urban , and regional planning; urban design ; architecture ; and landscape architecture . The committee has 11 members, in addition to two board members who act as observers and two ex officio members (NCC chairperson and CEO). Aside from
Alexandra Bridge - Misplaced Pages Continue
3780-552: The NCC's internal audit function, and reviews the special examinations and annual financial audits of the federal Office of the Auditor General . It also oversees the reporting of financial information, ensuring that the necessary processes and controls are in place for the NCC to achieve its objectives. This committee consists of 6 board members, plus the NCC chairperson and the CEO (as ex officio members). The Governance Committee reviews (and makes recommendations to
3870-646: The National Capital Region. The National Capital Region was expanded to a total of 4,660 km (1,150,000 acres) of land on both sides of the Ottawa River ; for one thing, the NCC acquired the funds to purchase lands to create the Greenbelt . The National Capital Act gave, and continues to give, the NCC statutory authority to implement its plans, an authority confirmed by the Supreme Court of Canada 's ruling in Munro v National Capital Commission . After
3960-569: The OIC was reorganized as the Federal District Commission ( FDC ). As its jurisdiction grew to include parts of Quebec , the FDC expanded the region's open spaces, extended parkways, improved Dow's Lake , and developed Confederation Square in conjunction with the City of Ottawa . In 1934, a citizens’ group urged the government to purchase land in the Gatineau Hills to save its forests. In 1937, three years later,
4050-567: The Todd Report, in 1903. Two of his major recommendations were the construction of a ceremonial boulevard linking Rideau Hall and the Parliament Buildings , and the preservation of large natural parks adjacent to the Capital. This plan was the first to recommend improvements north of the Ottawa River . Following the Todd Report was a master plan for Canada's Capital, tabled by Herbert S. Holt 's Federal Plan Commission (or,
4140-466: The architectural style of a particular residence." The Canadiana Fund consists of Cynthia Price Verreault (chairperson), Anne Fotheringham, Kathy Hays, Douglas B. Richardson, Deborah Riley, Harvey A. Slack, Candace Stevenson, Clyde Wells , and Fei Wong. The Advisory Committee on Universal Accessibility is mandated to assist the NCC by considering those projects that involve a significant universal accessibility component. It has 7 members—4 from outside
4230-455: The barges to pass so that work could continue on the superstructure. Considerable construction delays were caused by the severe winter conditions. By September 1900 the four fixed support spans were complete. The Canadian Society of Civil Engineers held its annual meeting in Ottawa in order that its members might tour the bridge works and see the preparations being made for placing the centre span. The bridge's main cantilever centre span was, at
4320-494: The benefit of their immediate resident, under provincial legislation, on issues like road maintenance, sewer, water and public transport. The NCC is the responsibility of the Minister of Public Works and Procurement , currently Filomena Tassi . In the 28th Canadian Ministry under Stephen Harper , the NCC reported to Parliament through the Minister of Foreign Affairs , and then through senior Ottawa-area cabinet ministers,
4410-418: The board on) matters relating to amendments to the by-laws; the selection criteria for, duties of and benefits for the chairperson, CEO and other board and committee members; the mandate, functioning, competency profile and performance appraisals of the board and its committees; the terms of reference and the selection process for the ombudsman ; and general governance issues. A minimum of 5 board members, plus
4500-407: The board. The scope of these annual meetings includes direct public input in a workshop to "discuss the NCC's strategic priorities for the coming year." As of May 2021 , current board members include: The CEO is accountable to the board of directors for the management of the NCC's operations and "the implementation of the board's strategic directions for the coming year." The following are
4590-661: The bridge are two major museums. In the Gatineau side of the river is the Canadian Museum of History while on the Ottawa side is the National Art Gallery while the Canadian Mint Museum and the former Canadian War Museum was located beside the Gallery. Also, on each end of the bridge are two major parks: Major's Hill Park (Ottawa) and Jacques Cartier Park (Gatineau) two major venues of
SECTION 50
#17327903008224680-588: The bridge was the site of a noted murder. Alain Brosseau, a waiter at the Château Laurier , was walking home to his apartment in Hull after finishing his shift at 11:30 pm. On his way he passed through Major's Hill Park . The park was known as a popular gay cruising area, and six youths were also in the park searching for homosexuals to rob and attack. They saw Brosseau and followed him when he walked to
4770-573: The bridge, believing incorrectly that he was gay. A short way across Brosseau was first hit with a stick and then robbed. Gang member Jeffrey Lalonde then lifted Brosseau and threw him off the bridge. Brosseau was killed instantly when he hit the rocks below. Lalonde was given a life sentence, and died in jail in 2008. The bridge is designated by the Canadian Society for Civil Engineering a National Historic Civil Engineering Site in June 1895. It
4860-518: The capital's six official residences; commercial, residential and heritage buildings; and agricultural facilities. The NCC reports to the Parliament of Canada through whichever minister in the Cabinet of Canada is designated responsible for the National Capital Act , currently the Minister of Public Services and Procurement . Through the 19th century, the character of what is known today as
4950-419: The committees and committee members of the NCC as of May 2021 . The 5-person Executive Committee is called upon when necessary to deal with specific business or issues. It can be delegated certain powers and functions by the board of directors. This Committee includes: Marc Seaman (chairperson), Mireille Apollon, Larry Beasley , Norm Odjick, and Tobi Nussbaum . The 8-person Audit Committee oversees
5040-407: The connections may also be required to transfer bending moment. Wood posts enable the fabrication of strong, direct, yet inexpensive connections between large trusses and walls. Exact details for post-to-truss connections vary from designer to designer, and may be influenced by post type. Solid-sawn timber and glulam posts are generally notched to form a truss bearing surface. The truss is rested on
5130-531: The curved roofs of aircraft hangars and other military buildings. Many variations exist in the arrangements of the members connecting the nodes of the upper arc with those of the lower, straight sequence of members, from nearly isosceles triangles to a variant of the Pratt truss. One of the simplest truss styles to implement, the king post consists of two angled supports leaning into a common vertical support. The queen post truss, sometimes queenpost or queenspost ,
5220-452: The design decisions beyond mere matters of economics. Modern materials such as prestressed concrete and fabrication methods, such as automated welding , have significantly influenced the design of modern bridges . Once the force on each member is known, the next step is to determine the cross section of the individual truss members. For members under tension the cross-sectional area A can be found using A = F × γ / σ y , where F
5310-403: The equilibrium condition described. Because the forces in each of its two main girders are essentially planar, a truss is usually modeled as a two-dimensional plane frame. However if there are significant out-of-plane forces, the structure must be modeled as a three-dimensional space. The analysis of trusses often assumes that loads are applied to joints only and not at intermediate points along
5400-414: The exact arrangement of forces is depending on the type of truss and again on the direction of bending. In the truss shown above right, the vertical members are in tension, and the diagonals are in compression. In addition to carrying the static forces, the members serve additional functions of stabilizing each other, preventing buckling . In the adjacent picture, the top chord is prevented from buckling by
5490-461: The first of the type), have the top and bottom chords of the truss arched, forming a lens shape. A lenticular pony truss bridge is a bridge design that involves a lenticular truss extending above and below the roadbed. American architect Ithiel Town designed Town's Lattice Truss as an alternative to heavy-timber bridges. His design, patented in 1820 and 1835, uses easy-to-handle planks arranged diagonally with short spaces in between them, to form
SECTION 60
#17327903008225580-417: The following conditions must hold: the sums of all (horizontal and vertical) forces, as well as all moments acting about the node equal zero. Analysis of these conditions at each node yields the magnitude of the compression or tension forces. Trusses that are supported at more than two positions are said to be statically indeterminate , and the application of Newton's Laws alone is not sufficient to determine
5670-492: The governance model of Washington, D.C. , was recommended. This Commission, reporting to the Government of Canada, would benevolently dictate the planning, development and operation of Canada's Capital. Ultimately, the Holt/Bennett General Plan was shelved; however, many of its technical recommendations were implemented over 40 years after it was written. In 1922, Noulan Cauchon , one of the founders of
5760-509: The implication that no moments exist at the jointed ends. This style of structure was named after the Belgian engineer Arthur Vierendeel , who developed the design in 1896. Its use for bridges is rare due to higher costs compared to a triangulated truss. The utility of this type of structure in buildings is that a large amount of the exterior envelope remains unobstructed and can be used for windows and door openings. In some applications this
5850-534: The last of whom was Pierre Poilievre . It is governed by the National Capital Act , which explains the boundaries of the National Capital Region in great detail. Its headquarters are in the Chambers Building on Elgin Street , between Queen and Sparks Streets. Oversight and direction of the NCC's operations and assets are the responsibility of its national board of directors. As defined in
5940-501: The member forces. In order for a truss with pin-connected members to be stable, it does not need to be entirely composed of triangles. In mathematical terms, the following necessary condition for stability of a simple truss exists: where m is the total number of truss members, j is the total number of joints and r is the number of reactions (equal to 3 generally) in a 2-dimensional structure. When m = 2 j − 3 {\displaystyle m=2j-3} ,
6030-562: The members means that longer diagonal members are only in tension for gravity load effects. This allows these members to be used more efficiently, as slenderness effects related to buckling under compression loads (which are compounded by the length of the member) will typically not control the design. Therefore, for given planar truss with a fixed depth, the Pratt configuration is usually the most efficient under static, vertical loading. The Southern Pacific Railroad bridge in Tempe , Arizona
6120-446: The members. Component connections are critical to the structural integrity of a framing system. In buildings with large, clearspan wood trusses, the most critical connections are those between the truss and its supports. In addition to gravity-induced forces (a.k.a. bearing loads), these connections must resist shear forces acting perpendicular to the plane of the truss and uplift forces due to wind. Depending upon overall building design,
6210-431: The members. The weight of the members is often insignificant compared to the applied loads and so is often omitted; alternatively, half of the weight of each member may be applied to its two end joints. Provided that the members are long and slender, the moments transmitted through the joints are negligible, and the junctions can be treated as " hinges " or "pin-joints". Under these simplifying assumptions, every member of
6300-427: The minimum cross section of the members, the last step in the design of a truss would be detailing of the bolted joints , e.g., involving shear stress of the bolt connections used in the joints. Based on the needs of the project, truss internal connections (joints) can be designed as rigid, semi rigid, or hinged. Rigid connections can allow transfer of bending moments leading to development of secondary bending moments in
6390-477: The nodes and result in forces in the members that are either tensile or compressive . For straight members, moments ( torques ) are explicitly excluded because, and only because, all the joints in a truss are treated as revolutes , as is necessary for the links to be two-force members. A planar truss is one where all members and nodes lie within a two-dimensional plane, while a space frame has members and nodes that extend into three dimensions . The top beams in
6480-463: The notches and bolted into place. A special plate/bracket may be added to increase connection load transfer capabilities. With mechanically-laminated posts, the truss may rest on a shortened outer-ply or on a shortened inner-ply. The later scenario places the bolts in double shear and is a very effective connection. National Capital Commission The National Capital Commission ( NCC ; French : Commission de la capitale nationale , CCN)
6570-438: The other hand, reducing the size of one member from the previous iteration merely makes the other members have a larger (and more expensive) safety factor than is technically necessary, but doesn't require another iteration to find a buildable truss. The effect of the weight of the individual truss members in a large truss, such as a bridge, is usually insignificant compared to the force of the external loads. After determining
6660-565: The planning and stewardship of the Capital, the NCC created the Urbanism Lab , where lectures, events, and public consultations take place on a regular basis. The NCC is the Capital's largest property owner, owning and managing over 11% of all lands in the Capital Region. As such, the NCC collaborates with the region's municipalities on various issues, including urban planning , safe and active transportation , and property and land stewardship . The Capital Region includes 13 municipalities,
6750-425: The presence of bracing and by the stiffness of the web members. The inclusion of the elements shown is largely an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection, the availability of machinery and the cost of labor. In other cases the appearance of the structure may take on greater importance and so influence
6840-406: The relation (a) is necessary, it is not sufficient for stability, which also depends on the truss geometry, support conditions and the load carrying capacity of the members. Some structures are built with more than this minimum number of truss members. Those structures may survive even when some of the members fail. Their member forces depend on the relative stiffness of the members, in addition to
6930-400: The same function as the flanges of an I-beam . Which chord carries tension and which carries compression depends on the overall direction of bending . In the truss pictured above right, the bottom chord is in tension, and the top chord in compression. The diagonal and vertical members form the truss web , and carry the shear stress . Individually, they are also in tension and compression,
7020-421: The steel structure, the bridge was closed to vehicle traffic. The closure was expected to end in fall of 2024 but has since been extended to February, 2025. The bridge replacement project is still in the planning phase, with several designs having been submitted and ongoing environmental and cultural impact assessments taking place and construction is expected to begin before 2032. Truss In engineering,
7110-404: The structural stability of that shape and design. A triangle is the simplest geometric figure that will not change shape when the lengths of the sides are fixed. In comparison, both the angles and the lengths of a four-sided figure must be fixed for it to retain its shape. The simplest form of a truss is one single triangle. This type of truss is seen in a framed roof consisting of rafters and
7200-702: The time of construction, the longest in Canada and the fourth-longest in the world. Both records are now held by the Quebec Bridge . The centre span was successfully put in place on October 7, and a locomotive made a trial run on December 12, 1900. On February 18, 1901, the bridge was officially inaugurated as the Interprovincial Bridge as it had been built by the Ottawa Interprovincial Bridge Company. The name
7290-421: The total load. The internal forces in the members of the truss can be calculated in a variety of ways, including graphical methods: A truss can be thought of as a beam where the web consists of a series of separate members instead of a continuous plate. In the truss, the lower horizontal member (the bottom chord ) and the upper horizontal member (the top chord ) carry tension and compression , fulfilling
7380-415: The truss is said to be statically determinate , because the ( m +3) internal member forces and support reactions can then be completely determined by 2 j equilibrium equations, once we know the external loads and the geometry of the truss. Given a certain number of joints, this is the minimum number of members, in the sense that if any member is taken out (or fails), then the truss as a whole fails. While
7470-519: The truss is then subjected to pure compression or pure tension forces – shear, bending moment, and other more-complex stresses are all practically zero. Trusses are physically stronger than other ways of arranging structural elements, because nearly every material can resist a much larger load in tension or compression than in shear, bending, torsion, or other kinds of force. These simplifications make trusses easier to analyze. Structural analysis of trusses of any type can readily be carried out using
7560-552: Was changed in September 1901 to the "Royal Alexandra Bridge" in honour of the new Queen during the visit of her son, the Duke of Cornwall and York, later George V . The Royal Alexandra Interprovincial Bridge crosses the Ottawa River just east of Parliament Hill at Nepean Point in Ottawa. The bridge was designed primarily to carry CPR trains but also had a track for local electric trolley service between Ottawa and Hull, as well as
7650-482: Was designated by the Canadian Society for Civil Engineering a National Historic Civil Engineering Site in June 1995. It was owned by the Canadian Pacific Railway until it was taken over by the National Capital Commission in 1970. It is now owned by the Government of Canada and maintained by Public Services and Procurement Canada (PSPC). In 2019, the Canadian government directed that the bridge
7740-565: Was established with the core mandate of improving and beautifying the city. What began as the OIC evolved as an organization in terms of both mandate and scope over 120 years. The OIC initially consisted of 4 (later 6) volunteer commissioners: three federal appointees, as well as the mayor of Ottawa . The OIC was supported by notable Capital builders, such as Government of Canada botanist William Saunders and Robert Surtees, former city engineer and designer of Major's Hill Park . The Commission acquired land as early as 1901, and its first priority
7830-400: Was owned by the Canadian Pacific Railway until it was taken over by the National Capital Commission in 1970. It is now (2018) owned by the Government of Canada and maintained by Public Services and Procurement Canada (PSPC). The bridge provided an important commuter link between Ottawa and Gatineau. The roadways for vehicles are located on the centre and east decks. Centre deck road surface
7920-415: Was patented in 1844 by two Boston railway engineers, Caleb Pratt and his son Thomas Willis Pratt . The design uses vertical members for compression and diagonal members to respond to tension . The Pratt truss design remained popular as bridge designers switched from wood to iron, and from iron to steel. This continued popularity of the Pratt truss is probably due to the fact that the configuration of
8010-475: Was to be replaced by the year 2029. Since 2023, the bridge has been closed to vehicle traffic but maintains a single lane for pedestrians and cyclists. The bridge was constructed by the Canadian Pacific Railway between 1898 and 1900. Four barges were built to move steel beams into position. During the winter (1899–1900) workmen toiled day and night chopping channels to keep the ice clear for
8100-627: Was to clean up the banks of the Rideau Canal , create and expand a park system , as well as a network of boulevards and parkways . One of the OIC's first projects was the Rideau Canal Driveway (now the Queen Elizabeth Driveway ). Four years following its establishment, the OIC hired Frederick G. Todd , a pioneer in landscape architecture , to aid in reshaping the city. Todd completed his plan, dubbed as
#821178