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44-559: The Granville Street Bridge or Granville Bridge is an eight-lane fixed cantilever / truss bridge in Vancouver , British Columbia , Canada, carrying Granville Street between Downtown Vancouver southwest and the Fairview neighborhood. It spans False Creek and is 27.4 m (90 ft) above Granville Island . The bridge is part of Highway 99 . The first Granville Bridge opened in 1889, crossing from Beach Ave to 3rd Ave and

88-691: A structure . Structural analysis , a discipline in engineering , analyzes the effects of loads on structures and structural elements. Excess load may cause structural failure , so this should be considered and controlled during the design of a structure. Particular mechanical structures—such as aircraft , satellites , rockets , space stations , ships , and submarines —are subject to their own particular structural loads and actions. Engineers often evaluate structural loads based upon published regulations , contracts , or specifications . Accepted technical standards are used for acceptance testing and inspection . In civil engineering , specified loads are

132-463: A Super Imposed Dead Load (SIDL) of around 5 pounds per square foot (psf) accounting for miscellaneous weight such as bolts and other fasteners, cabling, and various fixtures or small architectural elements. Live loads, on the other hand, can be furniture, moveable equipment, or the people themselves, and may increase beyond normal or expected amounts in some situations, so a larger factor of 1.6 attempts to quantify this extra variability. Snow will also use

176-500: A cantilever-winged sesquiplane built instead with wooden materials, the Fokker V.1 . In the cantilever wing, one or more strong beams, called spars , run along the span of the wing. The end fixed rigidly to the central fuselage is known as the root and the far end as the tip. In flight, the wings generate lift and the spars carry this load through to the fuselage. To resist horizontal shear stress from either drag or engine thrust,

220-628: A dozen years after the Wright Brothers ' initial flights, Junkers endeavored to eliminate virtually all major external bracing members in order to decrease airframe drag in flight. The result of this endeavor was the Junkers J 1 pioneering all-metal monoplane of late 1915, designed from the start with all-metal cantilever wing panels. About a year after the initial success of the Junkers J 1, Reinhold Platz of Fokker also achieved success with

264-483: A fire broke out on the bridge that was thought to be an arson attack. Four Germans were arrested. On February 4, 1954, the current Granville Street Bridge opened to traffic after five years of planning and construction; its dedication ceremony was attended by 5,000 spectators after it had been delayed a week due to heavy snow. The Vancouver Sun arranged for the first driver across the 1909 bridge, Sidney Annoot, to repeat her feat in 1954. The city government self-funded

308-438: A laboratory test method or to the normal usage of a material or structure. Live loads are usually variable or moving loads . These can have a significant dynamic element and may involve considerations such as impact , momentum , vibration , slosh dynamics of fluids, etc. An impact load is one whose time of application on a material is less than one-third of the natural period of vibration of that material. Cyclic loads on

352-416: A maximum factor of 1.6, while lateral loads (earthquakes and wind) are defined such that a 1.0 load factor is practical. Multiple loads may be added together in different ways, such as 1.2*Dead + 1.0*Live + 1.0*Earthquake + 0.2*Snow, or 1.2*Dead + 1.6(Snow, Live(roof), OR Rain) + (1.0*Live OR 0.5*Wind). For aircraft, loading is divided into two major categories: limit loads and ultimate loads. Limit loads are

396-517: A new separated bike and walking path located in the centre of the bridge roadway. The plan was opened up for public comment in April 2019 with the project approved. Construction on the pedestrian and bicycle lanes began in February 2023 and is expected to take two years to complete. Cantilever When subjected to a structural load at its far, unsupported end, the cantilever carries the load to

440-495: A plan to remove the "Granville Loops" - a pair of cloverleaf off-ramps connecting the bridge with Pacific Street - and open up the land to redevelopment. The Granville Street Bridge underwent a seismic retrofit that began in late 2018 and was completed in September 2021. In January 2019, Vancouver City Council announced a plan to improve pedestrian and cyclist access to the bridge from the surrounding neighbourhoods by creating

484-810: A structure can lead to fatigue damage, cumulative damage, or failure. These loads can be repeated loadings on a structure or can be due to vibration . Imposed loads are those associated with occupation and use of the building; their magnitude is less clearly defined and is generally related to the use of the building. Structural loads are an important consideration in the design of buildings. Building codes require that structures be designed and built to safely resist all actions that they are likely to face during their service life, while remaining fit for use. Minimum loads or actions are specified in these building codes for types of structures, geographic locations, usage and building materials . Structural loads are split into categories by their originating cause. In terms of

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528-404: A structure, such as: A load combination results when more than one load type acts on the structure. Building codes usually specify a variety of load combinations together with load factors (weightings) for each load type in order to ensure the safety of the structure under different maximum expected loading scenarios. For example, in designing a staircase , a dead load factor may be 1.2 times

572-503: A variation in this parameter indicates the concentration of the analyte . Recently, microcantilevers have been fabricated that are porous, allowing for a much larger surface area for analyte to bind to, increasing sensitivity by raising the ratio of the analyte mass to the device mass. Surface stress on microcantilever, due to receptor-target binding, which produces cantilever deflection can be analyzed using optical methods like laser interferometry. Zhao et al., also showed that by changing

616-458: A wire-braced design. However, as the speed of the aircraft increases, the drag of the bracing increases sharply, while the wing structure must be strengthened, typically by increasing the strength of the spars and the thickness of the skinning. At speeds of around 200 miles per hour (320 km/h) the drag of the bracing becomes excessive and the wing strong enough to be made a cantilever without excess weight penalty. Increases in engine power through

660-544: Is also a dead load. Dead loads are also known as permanent or static loads . Building materials are not dead loads until constructed in permanent position. IS875(part 1)-1987 give unit weight of building materials, parts, components. Live loads, or imposed loads, are temporary, of short duration, or a moving load . These dynamic loads may involve considerations such as impact , momentum , vibration , slosh dynamics of fluids and material fatigue . Live loads, sometimes also referred to as probabilistic loads, include all

704-411: Is an example of a cantilever truss bridge . A cantilever in a traditionally timber framed building is called a jetty or forebay . In the southern United States, a historic barn type is the cantilever barn of log construction . Temporary cantilevers are often used in construction. The partially constructed structure creates a cantilever, but the completed structure does not act as a cantilever. This

748-455: Is force and w {\displaystyle w} is the cantilever width. The spring constant is related to the cantilever resonance frequency ω 0 {\displaystyle \omega _{0}} by the usual harmonic oscillator formula ω 0 = k / m equivalent {\displaystyle \omega _{0}={\sqrt {k/m_{\text{equivalent}}}}} . A change in

792-582: Is one of their chief advantages. Many box girder bridges are built segmentally , or in short pieces. This type of construction lends itself well to balanced cantilever construction where the bridge is built in both directions from a single support. These structures rely heavily on torque and rotational equilibrium for their stability. In an architectural application, Frank Lloyd Wright 's Fallingwater used cantilevers to project large balconies. The East Stand at Elland Road Stadium in Leeds was, when completed,

836-401: Is the cantilever thickness. Very sensitive optical and capacitive methods have been developed to measure changes in the static deflection of cantilever beams used in dc-coupled sensors. The second is the formula relating the cantilever spring constant k {\displaystyle k} to the cantilever dimensions and material constants: where F {\displaystyle F}

880-422: Is the immunosensor based on an antibody layer that interacts selectively with a particular immunogen and reports about its content in a specimen. In the static mode of operation, the sensor response is represented by the beam bending with respect to a reference microcantilever. Alternatively, microcantilever sensors can be operated in the dynamic mode. In this case, the beam vibrates at its resonance frequency and

924-461: Is very helpful when temporary supports, or falsework , cannot be used to support the structure while it is being built (e.g., over a busy roadway or river, or in a deep valley). Therefore, some truss arch bridges (see Navajo Bridge ) are built from each side as cantilevers until the spans reach each other and are then jacked apart to stress them in compression before finally joining. Nearly all cable-stayed bridges are built using cantilevers as this

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968-528: The BC Electric ) ran a single-track on a trestle on the east side of the bridge for the "Fairview Belt Line" which connected Granville Street, 9th Avenue (now Broadway) and Main Street with downtown, hoping it would help spur development, which it did. The second bridge was completed in 1909. It was a longer, medium-level steel bridge with a through truss swing span. During World War I , on April 29, 1915,

1012-632: The maximum loads a component or structure may carry safely. Ultimate loads are the limit loads times a factor of 1.5 or the point beyond which the component or structure will fail. Gust loads are determined statistically and are provided by an agency such as the Federal Aviation Administration . Crash loads are loosely bounded by the ability of structures to survive the deceleration of a major ground impact . Other loads that may be critical are pressure loads (for pressurized, high-altitude aircraft) and ground loads. Loads on

1056-425: The actual load on a structure, there is no difference between dead or live loading, but the split occurs for use in safety calculations or ease of analysis on complex models. To meet the requirement that design strength be higher than maximum loads, building codes prescribe that, for structural design, loads are increased by load factors. These load factors are, roughly, a ratio of the theoretical design strength to

1100-432: The attachment protocol of the receptor on the microcantilever surface, the sensitivity can be further improved when the surface stress generated on the microcantilever is taken as the sensor signal. Structural load A structural load or structural action is a mechanical load (more generally a force ) applied to structural elements . A load causes stress , deformation , displacement or acceleration in

1144-395: The behavior of MEMS cantilevers. The first is Stoney's formula , which relates cantilever end deflection δ to applied stress σ: where ν {\displaystyle \nu } is Poisson's ratio , E {\displaystyle E} is Young's modulus , L {\displaystyle L} is the beam length and t {\displaystyle t}

1188-444: The best estimate of the actual loads a structure is expected to carry. These loads come in many different forms, such as people, equipment, vehicles, wind, rain, snow, earthquakes, the building materials themselves, etc. Specified loads also known as characteristic loads in many cases. Buildings will be subject to loads from various sources. The principal ones can be classified as live loads (loads which are not always present in

1232-401: The bridge project, which cost $ 16.5 million (equivalent to $ 184 million in 2023 dollars), with "no formal assistance given by any other government body" according to mayor Frederick Hume . A million vehicles crossed over the bridge in its first month. The eight-lane structure was constructed from 1951 to 1954 on the same alignment as the first bridge. Steel plate girders salvaged from

1276-518: The cantilever structure to release it, often with an anisotropic wet or dry etching technique. Without cantilever transducers, atomic force microscopy would not be possible. A large number of research groups are attempting to develop cantilever arrays as biosensors for medical diagnostic applications. MEMS cantilevers are also finding application as radio frequency filters and resonators . The MEMS cantilevers are commonly made as unimorphs or bimorphs . Two equations are key to understanding

1320-581: The force applied to a cantilever can shift the resonance frequency. The frequency shift can be measured with exquisite accuracy using heterodyne techniques and is the basis of ac-coupled cantilever sensors. The principal advantage of MEMS cantilevers is their cheapness and ease of fabrication in large arrays. The challenge for their practical application lies in the square and cubic dependences of cantilever performance specifications on dimensions. These superlinear dependences mean that cantilevers are quite sensitive to variation in process parameters, particularly

1364-583: The forces that are variable within the object's normal operation cycle not including construction or environmental loads. Roof and floor live loads are produced during maintenance by workers, equipment and materials, and during the life of the structure by movable objects, such as planters and people. Bridge live loads are produced by vehicles traveling over the deck of the bridge. Environmental loads are structural loads caused by natural forces such as wind, rain, snow, earthquake or extreme temperatures. Engineers must also be aware of other actions that may affect

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1408-693: The largest cantilever stand in the world holding 17,000 spectators. The roof built over the stands at Old Trafford uses a cantilever so that no supports will block views of the field. The old (now demolished) Miami Stadium had a similar roof over the spectator area. The largest cantilevered roof in Europe is located at St James' Park in Newcastle-Upon-Tyne , the home stadium of Newcastle United F.C. Less obvious examples of cantilevers are free-standing (vertical) radio towers without guy-wires , and chimneys , which resist being blown over by

1452-485: The late 1920s and early 1930s raised speeds through this zone and by the late 1930s cantilever wings had almost wholly superseded braced ones. Other changes such as enclosed cockpits, retractable undercarriage, landing flaps and stressed-skin construction furthered the design revolution, with the pivotal moment widely acknowledged to be the MacRobertson England-Australia air race of 1934, which

1496-460: The maximum load expected in service. They are developed to help achieve the desired level of reliability of a structure based on probabilistic studies that take into account the load's originating cause, recurrence, distribution, and static or dynamic nature. The dead load includes loads that are relatively constant over time, including the weight of the structure itself, and immovable fixtures such as walls, plasterboard or carpet . The roof

1540-609: The second bridge were made into barges for constructing the foundations of the Oak Street Bridge . Initially only four lanes were open to traffic until the completion of the loop ramps on the north side on July 16. The bridge's wide design was meant to accommodate a future freeway that would serve downtown; those plans were cancelled in the 1960s. Recent improvements to the bridge include increasing its earthquake resistance , and installing higher curbs and median barriers . In December 2017, Vancouver City Council approved

1584-495: The structure), dead loads (loads which are permanent and immovable excepting redesign or renovation) and wind load, as described below. In some cases structures may be subject to other loads, such as those due to earthquakes or pressures from retained material. The expected maximum magnitude of each is referred to as the characteristic load. Dead loads are static forces that are relatively constant for an extended time. They can be in tension or compression . The term can refer to

1628-487: The support where it applies a shear stress and a bending moment . Cantilever construction allows overhanging structures without additional support. Cantilevers are widely found in construction, notably in cantilever bridges and balconies (see corbel ). In cantilever bridges, the cantilevers are usually built as pairs, with each cantilever used to support one end of a central section. The Forth Bridge in Scotland

1672-399: The thickness as this is generally difficult to accurately measure. However, it has been shown that microcantilever thicknesses can be precisely measured and that this variation can be quantified. Controlling residual stress can also be difficult. A chemical sensor can be obtained by coating a recognition receptor layer over the upper side of a microcantilever beam. A typical application

1716-576: The weight of the structure, and a live load factor may be 1.6 times the maximum expected live load. These two "factored loads" are combined (added) to determine the "required strength" of the staircase. The size of the load factor is based on the probability of exceeding any specified design load. Dead loads have small load factors, such as 1.2, because weight is mostly known and accounted for, such as structural members, architectural elements and finishes, large pieces of mechanical, electrical and plumbing (MEP) equipment, and for buildings, it's common to include

1760-424: The wind through cantilever action at their base. The cantilever is commonly used in the wings of fixed-wing aircraft . Early aircraft had light structures which were braced with wires and struts . However, these introduced aerodynamic drag which limited performance. While it is heavier, the cantilever avoids this issue and allows the plane to fly faster. Hugo Junkers pioneered the cantilever wing in 1915. Only

1804-453: The wing must also form a stiff cantilever in the horizontal plane. A single-spar design will usually be fitted with a second smaller drag-spar nearer the trailing edge , braced to the main spar via additional internal members or a stressed skin. The wing must also resist twisting forces, achieved by cross-bracing or otherwise stiffening the main structure. Cantilever wings require much stronger and heavier spars than would otherwise be needed in

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1848-614: Was designed by the Canadian Pacific Railway (CPR). It had a swing span near the downtown side, was wide enough for two wagons, had a 4-foot (1.2 m) wide separated path on the west side for pedestrians, and was barely above high tide – children swam from it in the summer. Two years after it was built, the CPR cleared the Fairview Slopes and opened them for settlement; the street railway company (predecessor of

1892-551: Was part of the scheme to clear Granville Street through to the North Arm of the Fraser River, where a bridge crossed to the farming community of Eburne. Granville Street was called Centre Street south of False Creek (until 1907) and the new slit through the forest heading south was initially known as North Arm Road. The 2,400-metre (7,900 ft) long, low timber trestle bridge opened on January 4, costing $ 16,000 to build, and

1936-677: Was won by a de Havilland DH.88 Comet . Currently, cantilever wings are almost universal with bracing only being used for some slower aircraft where a lighter weight is prioritized over speed, such as in the ultralight class. Cantilevered beams are the most ubiquitous structures in the field of microelectromechanical systems (MEMS). An early example of a MEMS cantilever is the Resonistor, an electromechanical monolithic resonator. MEMS cantilevers are commonly fabricated from silicon (Si), silicon nitride (Si 3 N 4 ), or polymers . The fabrication process typically involves undercutting

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