|
Rigid-frame Bridge
A rigid-frame bridge is a bridge in which the superstructure and substructure are rigidly connected to act as a continuous unit. Typically, the structure is cast monolithically, making the structure continuous from deck to foundation. The connections between members are rigid connections which transfer bending moment, axial forces, and shear forces. A bridge design consisting of a rigid frame can provide significant structural benefits, but can also be difficult to design and/or construct. History The use of rigid-frame bridges began in Germany in the early twentieth century and quickly spread to the Americas. Emílio Henrique Baumgart and Arthur G. Hayden, in particular, gained notoriety for their use of concrete rigid frames in the early 1920s. At the time, reinforced concrete was commonly used in bridge designEncyclopædia Britannica"Reinforced Concrete" November 2014 but the superstructure was designed with bearings on the substructure. In concrete rigid-frame design, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Bridge MerrittPkwy
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, which is usually something that is otherwise difficult or impossible to cross. There are many different designs of bridges, each serving a particular purpose and applicable to different situations. Designs of bridges vary depending on factors such as the function of the bridge, the nature of the terrain where the bridge is constructed and anchored, the material used to make it, and the funds available to build it. The earliest bridges were likely made with fallen trees and stepping stones. The Neolithic people built boardwalk bridges across marshland. The Arkadiko Bridge, dating from the 13th century BC, in the Peloponnese is one of the oldest arch bridges in existence and use. Etymology The ''Oxford English Dictionary'' traces the origin of the word ''bridge' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Beam (structure)
A beam is a structural element that primarily resists loads applied laterally across the beam's axis (an element designed to carry a load pushing parallel to its axis would be a strut or column). Its mode of deflection is primarily by bending, as loads produce reaction forces at the beam's support points and internal bending moments, shear, stresses, strains, and deflections. Beams are characterized by their manner of support, profile (shape of cross-section), equilibrium conditions, length, and material. Beams are traditionally descriptions of building or civil engineering structural elements, where the beams are horizontal and carry vertical loads. However, any structure may contain beams, such as automobile frames, aircraft components, machine frames, and other mechanical or structural systems. Any structural element, in any orientation, that primarily resists loads applied laterally across the element's axis is a beam. Overview Historically a beam is a squared ti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Rigid Frame Bridge
Rigid or rigidity may refer to: Mathematics and physics *Stiffness, the property of a solid body to resist deformation, which is sometimes referred to as rigidity *Structural rigidity, a mathematical theory of the stiffness of ensembles of rigid objects connected by hinges *Rigidity (electromagnetism), the resistance of a charged particle to deflection by a magnetic field *Rigidity (mathematics), a property of a collection of mathematical objects (for instance sets or functions) *Rigid body, in physics, a simplification of the concept of an object to allow for modelling *Rigid transformation, in mathematics, a rigid transformation preserves distances between every pair of points *Rigidity (chemistry), the tendency of a substance to retain/maintain their shape when subjected to outside force *(Modulus of) rigidity or shear modulus (material science), the tendency of a substance to retain/maintain their shape when subjected to outside force Medicine *Rigidity (neurology), an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Beam Bridge
Beam bridges are the simplest structural forms for bridge spans supported by an abutment or pier at each end. No moments are transferred throughout the support, hence their structural type is known as '' simply supported''. The simplest beam bridge could be a log (see log bridge), a wood plank, or a stone slab (see clapper bridge) laid across a stream. Bridges designed for modern infrastructure will usually be constructed of steel or reinforced concrete, or a combination of both. The concrete elements may be reinforced or prestressed. Such modern bridges include girder, plate girder, and box girder bridges, all types of beam bridges. Types of construction could include having many beams side by side with a deck across the top of them, to a main beam either side supporting a deck between them. The main beams could be I-beams, trusses, or box girders. They could be half-through, or braced across the top to create a through bridge. Since no moments are transferred, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Profile (engineering)
In standardization, a profile is a subset internal to a specification. Aspects of a complex technical specification may necessarily have more than one interpretation, and there are probably many optional features. These aspects constitute a profile of the standard. Two implementations engineered from the same description may not interoperate due to having a different profile of the standard. Vendors can even ignore features that they view as unimportant, yet prevail in the long run. The use of profiles in these ways can force one interpretation, or create de facto standards from official standards. Engineers can design or procure by using a profile to ensure interoperability. For example, the International Standard Profile, ISP, is used by the ISO in their ISO ISP series of standards; in the context of OSI networking, Britain uses the UK-GOSIP profile and the US uses US- GOSIP; there are also various mobile profiles adopted by the W3C for web standards. In particular, impleme ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
North Carolina Department Of Transportation
The North Carolina Department of Transportation (NCDOT) is responsible for building, repairing, and operating highways, bridges, and other modes of transportation, including ferries in the U.S. state of North Carolina. History The North Carolina Department of Transportation was formed in 1915 as the State Highway Commission. In 1931, the commission was restructured to include a chair and six other members appointed by the governor. It also assumed responsibility for the maintenance of all county roads in the state and all inmates of county jails sentenced to over 60 days incarceration. In 1933, the agency was merged with the state prison system to form the State Highway and Public Works Commission. In 1941 the Department of Motor Vehicles (DMV) was formed under the NCDoT by an act of the North Carolina General Assembly, General Assembly. The Executive Organization Act of 1971 combined the state highway commission and the DMV to form the NC Department of Transportation and Highway ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Parkways
A parkway is a landscaped thoroughfare. The term is particularly used for a roadway in a park or connecting to a park from which trucks and other heavy vehicles are excluded. Over the years, many different types of roads have been labeled parkways. The term may be used to describe city streets as narrow as two lanes with a landscaped median, wide landscaped setbacks, or both. The term has also been applied to scenic highways and to limited-access roads more generally. Many parkways originally intended for scenic, recreational driving have evolved into major urban and commuter routes. United States Scenic roads The first parkways in the United States were developed during the late 19th century by landscape architects Frederick Law Olmsted and Calvert Vaux as roads that separated pedestrians, bicyclists, equestrians, and horse carriages, such as Eastern Parkway, which is credited as the world's first parkway, and Ocean Parkway in the New York City borough of Brooklyn. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Statically Indeterminate
In statics and structural mechanics, a structure is statically indeterminate when the equilibrium equations force and moment equilibrium conditions are insufficient for determining the internal forces and reactions on that structure. Mathematics Based on Newton's laws of motion, the equilibrium equations available for a two-dimensional body are: : \sum \mathbf F = 0 : the vectorial sum of the forces acting on the body equals zero. This translates to: :: \sum \mathbf H = 0 : the sum of the horizontal components of the forces equals zero; :: \sum \mathbf V = 0 : the sum of the vertical components of forces equals zero; : \sum \mathbf M = 0 : the sum of the moments (about an arbitrary point) of all forces equals zero. In the beam construction on the right, the four unknown reactions are , , , and . The equilibrium equations are: : \begin \sum \mathbf V = 0 \quad & \implies \quad \mathbf V_A - \mathbf F_v + \mathbf V_B + \mathbf V_C = 0 \\ \sum \mathbf H = 0 \quad & \implies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Rebar
Rebar (short for reinforcement bar or reinforcing bar), known when massed as reinforcing steel or steel reinforcement, is a tension device added to concrete to form ''reinforced concrete'' and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under compression, but has low tensile strength. Rebar usually consists of steel bars which significantly increase the tensile strength of the structure. Rebar surfaces feature a continuous series of ribs, lugs or indentations to promote a better bond with the concrete and reduce the risk of slippage. The most common type of rebar is carbon steel, typically consisting of hot-rolled round bars with deformation patterns embossed into its surface. Steel and concrete have similar coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal differential stress as the temperature changes. Other readily available types of rebar are manufacture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Abutment
An abutment is the substructure at the ends of a bridge span or dam supporting its superstructure. Single-span bridges have abutments at each end that provide vertical and lateral support for the span, as well as acting as retaining walls to resist lateral movement of the earthen fill of the bridge approach. Multi-span bridges require piers to support ends of spans unsupported by abutments. Dam abutments are generally the sides of a valley or gorge, but may be artificial in order to support arch dams such as Kurobe Dam in Japan. The civil engineering term may also refer to the structure supporting one side of an arch, or masonry used to resist the lateral forces of a vault.Pevsner, N. (1970) ''Cornwall''; 2nd ed. Harmondsworth: Penguin; p. 245 The impost or abacus An abacus ( abaci or abacuses), also called a counting frame, is a hand-operated calculating tool which was used from ancient times in the ancient Near East, Europe, China, and Russia, until the adoptio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Span (architecture)
In engineering, span is the distance between two adjacent structural supports (e.g., two piers) of a structural member (e.g., a beam). Span is measured in the horizontal direction either between the faces of the supports (clear span) or between the centers of the bearing surfaces (effective span): A span can be closed by a solid beam or by a rope. The first kind is used for bridges, the second one for power lines, overhead telecommunication lines, some type of antennas or for aerial tramways. Span is a significant factor in finding the strength and size of a beam as it determines the maximum bending moment and deflection. The maximum bending moment M_ and deflection \delta_in the pictured beam is found using: :M_ = \frac :\delta_ = \frac = \frac where :q = Uniformly distributed load :L = Length of the beam between two supports (span) :E = Modulus of elasticity :I = Area moment of inertia The maximum bending moment and deflection occur midway between the two ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
