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Movable Scaffolding System
A movable scaffolding system (MSS) is a special-purpose self-launching form used in bridge construction, specifically prestressed concrete bridges with segments or spans that are cast in place. The movable scaffolding system is used to support a form while the concrete is cured; once the segment is complete, the scaffold and forms are moved to the end of the new segment and another segment is poured. While superficially similar, movable scaffolding systems should not be confused with launching gantry machines, which also are used in segmental bridge construction. Both feature long girders spanning multiple bridge spans which move with and temporarily support the work, but launching gantry machines are used to lift and support precast bridge segments and bridge girders, while movable scaffolding systems are used for cast-in-place construction. Operation and design An MSS is generally used instead of a launching gantry to minimize the number of joints, since the cast in place segm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bridge
A bridge is a structure built to span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way 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, and 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 still in existence and use. Etymology The '' Oxford English Dictionary'' traces the origin of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ferroconcrete
Reinforced concrete (RC), also called reinforced cement concrete (RCC) and ferroconcrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ductility. The reinforcement is usually, though not necessarily, steel bars (rebar) and is usually embedded passively in the concrete before the concrete sets. However, post-tensioning is also employed as a technique to reinforce the concrete. In terms of volume used annually, it is one of the most common engineering materials. In corrosion engineering terms, when designed correctly, the alkalinity of the concrete protects the steel rebar from corrosion. Description Reinforcing schemes are generally designed to resist tensile stresses in particular regions of the concrete that might cause unacceptable cracking and/or structural failure. Modern reinforced concrete can contain varied reinforcing materials made of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concrete Bridge
Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most widely used building material. Its usage worldwide, ton for ton, is twice that of steel, wood, plastics, and aluminum combined. Globally, the ready-mix concrete industry, the largest segment of the concrete market, is projected to exceed $600 billion in revenue by 2025. This widespread use results in a number of environmental impacts. Most notably, the production process for cement produces large volumes of greenhouse gas emissions, leading to net 8% of global emissions. Other environmental concerns include widespread illegal sand mining, impacts on the surrounding environment such as increased surface runoff or urban heat island effect, and potential public health implications from toxic ingredients. Significant research and development is b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cast In Place Concrete
Cast-in-place concrete or Cast-in-situ concrete is a technology of construction of buildings where walls and slabs of the buildings are cast at the site in formwork. This differs from precast concrete technology where slabs are cast elsewhere and then brought to the construction site and assembled. It uses concrete slabs for walls instead of bricks or wooden panels, and formwork is used for both walls and roof. Advantages of this technology are strength of the building, insulation, and versatility for different types of buildings. A disadvantage is the high amount of labor required to install and remove formwork. See also * Precast concrete * Formwork Formwork is Molding (process), molds into which concrete or similar materials are either precast concrete, precast or cast-in-place concrete, cast-in-place. In the context of concrete construction, the falsework supports the shuttering mold ... References Building engineering {{civil-engineering-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Launching Gantry
A launching gantry (also called beam launcher, girder launcher, bridge building crane, and bridge-building machine, locally nicknamed the "Iron Monster") is a special-purpose mobile gantry crane used in bridge construction, specifically segmental bridges that use precast box girder bridge segments or precast girders in highway and high-speed rail bridge construction projects. The launching gantry is used to lift and support bridge segments or girders as they are placed while being supported by the bridge piers instead of the ground. While superficially similar, launching gantry machines should not be confused with movable scaffolding systems, which also are used in segmental bridge construction. Both feature long girders spanning multiple bridge spans which move with the work, but launching gantry machines are used to lift and support precast bridge segments and bridge girders, while movable scaffolding systems are used for cast-in-place construction of bridge segments. Operati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Segmental Bridge
A segmental bridge is a bridge built in short sections (called segments), i.e., one piece at a time, as opposed to traditional methods that build a bridge in very large sections. The bridge is made of concrete that is either cast-in-place (constructed fully in its final location) or precast concrete (built at another location and then transported to their final location for placement in the full structure). These bridges are very economical for long spans (more than ), especially when access to the construction site is restricted. They are also chosen for their aesthetic appeal. History The first cantilevered segmental cast-in-place concrete bridge, built in 1930, was across Rio do Peixe in the state of Santa Catarina of Brazil. It was followed in 1951 by the prestressed concrete bridge across the Lahn River in , the first of many cantilevered bridges designed by . The first prestressed concrete bridge, assembled by several precast elements, was the across the river Marne in F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Falsework
Falsework consists of temporary structures used in construction to support a permanent structure until its construction is sufficiently advanced to support itself. For arches, this is specifically called centering. Falsework includes temporary support structures for formwork used to mold concreteHardie G.M. (1995) Building Construction: Principles, Practices, and Materials. New Jersey: Prentice Hall. (Pg 116, paragraph 1) in the construction of buildings, bridges, and elevated roadways. The British Standards of practice for falsework, BS 5975:2008, defines falsework as "Any temporary structure used to support a permanent structure while it is not self-supporting." History Falsework has been employed in bridge and viaduct construction since ancient times. The Romans were renowned for its use, as at the Limyra Bridge in Turkey. Until the turn of the 20th century almost all falsework was constructed from timber. To compensate for timber shortages in different regions and to rati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precast
Precast concrete is a construction product produced by casting concrete in a reusable mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples include precast beams, and wall panels for tilt up construction. In contrast, cast-in-place concrete is poured into site-specific forms and cured on site. Recently lightweight expanded polystyrene foam is being used as the cores of precast wall panels, saving weight and increasing thermal insulation. Precast stone is distinguished from precast concrete by the finer aggregate used in the mixture, so the result approaches the natural product. Overview Precast concrete is employed in both interior and exterior applications, from highway, bridge, and hi-rise projects to tilt-up building construction. By producing precast concrete in a controlled environment (typically referred to as a precast plant), the precast concrete is afforded the opportunity to proper ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebar
Rebar (short for reinforcing bar), known when massed as reinforcing steel or reinforcement steel, is a steel bar used as a Tension (physics), tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under Compression (physics), compression, but has weak tensile strength. Rebar significantly increases the tensile strength of the structure. Rebar's surface features 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 coefficient of thermal expansion, coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal differential stress (mechanics), stress as the temperature changes. Other readily available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Beach International Gateway
The Long Beach International Gateway is a cable-stayed bridge that carries six lanes of Interstate 710 and a bicycle/pedestrian path in Long Beach, California, west across the Back Channel to Terminal Island. The bridge replaced the Gerald Desmond Bridge, which was completed in 1968 and named after Gerald Desmond, a prominent civic leader and a former city attorney for the City of Long Beach. The 1968 steel arch bridge developed numerous issues, and the Port of Long Beach decided it would be best, from an economical perspective, that the bridge be replaced. After several years of studies, a cable-stayed bridge with of vertical clearance to be built north of the existing bridge was identified as the preferred alternative in the final environmental impact report (2010 FEIR). The new bridge allows access to the port for the tallest container ships after the older bridge is demolished. It is the first long-span cable-stayed bridge in California and the first and only cable-stayed b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Long Beach, California
Long Beach is a city in Los Angeles County, California. It is the 42nd-most populous city in the United States, with a population of 466,742 as of 2020. A charter city, Long Beach is the seventh-most populous city in California. Incorporated in 1897, Long Beach lies in Southern California in the southern part of Los Angeles County. Long Beach is approximately south of downtown Los Angeles, and is part of the Gateway Cities region. The Port of Long Beach is the second busiest container port in the United States and is among the world's largest shipping ports. The city is over an oilfield with minor wells both directly beneath the city as well as offshore. The city is known for its waterfront attractions, including the permanently docked and the Aquarium of the Pacific. Long Beach also hosts the Grand Prix of Long Beach, an IndyCar race and the Long Beach Pride Festival and Parade. California State University, Long Beach, one of the largest universities in California b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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