ConstructingWorld

Rio-Niterói Bridge ,the sixth longest  bridge in the world and the longest prestressed concrete bridge in the southern hemisphere also known as President Costa e Silva Bridge . It runs 13.290 kilometres (8.258 mi) long – 8.836 kilometres (5.490 mi) over water and the bridge's 300-metre (980 ft) central span is 72 metres (236 ft) high in order to allow the passage of hundreds of ships entering and leaving the bay every month. OVER-WATER APPROACHES The over-water approach spans consist of twin precast post tensioned concrete box girders constant span length of 80 m is used for the continuous spans. Expansion joints are provided 20 m from the piers in every fifth or sixth span. The structure depth is 4.7 m. The piers for the approach structure are of cellular reinforced concrete and rest on footing blocks near the water surface and on 2-m-diameter reinforced concrete piles reaching to competent founding strata below water. Precast concrete segments were cast in a yard, barged

Girders are built for carrying dynamic loads and rolling loads. This is what makes them preferable for bridge construction, where load amount is not constant. Dynamic loads are those that exert varying amounts of force upon a structure. Dynamic loads are contrast with static loads, which exert the same amount of force at all times. It takes a special kind of beam to withstand dynamic loads with consistent, unfailing strength. Girder beams have the ideal structure and capabilities for withstanding heavy dynamic loads. In general, effective spans of about 25 to 150 meters are applied, but the Costa e Silva Bridge (Brazil) was built with the longest effective span of 300 meters. JFE Engineering has the most experience in the manufacture and construction of bridges of this type. Cross Section of a Girder (Box Girder) Diaphragms are adopted in concrete box girder bridges to transfer loads from bridge decks to bearings. Since the depth of diaphragms normally exceeds the width

INTRO The Petronas Twin Towers are twin high rises located in Kuala Lumpur, Malaysia. They were designed by Argentinean-American architect Cesar Pelli and built by two separate construction consortiums headed by Hazama Corp. and Samsung Engineering and Construction between the years 1992 and 1997. The Towers have 88 stories each and stand 1,483 feet (452 m) tall. The Council on Tall Buildings and Urban Habitat certified the Towers as the world’s tallest buildings in 1996, based on their structural top. They retained the title until 2004 when the Taipei 101 surpassed them. The project cost US$1.8 billion to build. DESIGNING The design for the PETRONAS Towers was not a written document or a set of drawings for the contractors to follow when building the structure.  It was instead an evolving process that took place over the course of many years.  This enormous amount of communication and the design considerations that were discussed produced a final result that

ROLLER SUPPORTS Roller supports are free to rotate and translate along the surface upon which the roller rests. The surface can be horizontal, vertical, or sloped at any angle. The resulting reaction force is always a single force that is perpendicular to, and away from, the surface. Roller supports are commonly located at one end of long bridges. This allows the bridge structure to expand and contract with temperature changes. The expansion forces could fracture the supports at the banks if the bridge structure was "locked" in place. Roller supports can also take the form of rubber bearings, rockers, or a set of gears which are designed to allow a limited amount of lateral movement. How it looks.. . Roller support in a Bridge PINNED SUPPORTS A pinned support can resist both vertical and horizontal forces but not a moment. They will allow the structural member to rotate, but not to translate in any direction. Many connections are ass

M any, almost all of us would have come across the statement " Concrete is weak in Tension", why is it so......... Concrete is not a homogeneous material like steel which is strong in both tension as well as compression. It is a composite material and is obtained by mixing cementing materials, water and aggregate (and sometimes admixtures). Interfacial Transition zone (ITZ) in  concrete The "interface zone" is the weakest link in the structure. When compressing, that interface only serves to transfer compressive stresses from one aggregate to the next. That does not require exceptional strength. Under tension, the aggregates are trying to pull away from each other so this interfacial transition zone has to bear tensile stresses to holds the whole system together.  Since its strength significantly weaker than the aggregates, so the failure starts at much lower stresses. .

RESEARCHERS IN Spain are developing an earthquake-resistant brick that they say could be incorporated into interior brick walls to stabilize them during seismic events. Dubbed Sisbrick by its creators at the Universitat Politècnica de València, the material is capable of absorbing greater horizontal movements than is the case with standard brick while still supporting vertical loads that can affect a building’s structural integrity. The bricks are designed to be arranged in a pattern within partition walls made mostly of standard bricks, and the researchers say that Sisbrick would enable such a wall to absorb three times as much horizontal movement as a typical brick wall. The arrangement would essentially isolate the wall from the building’s structural frame during a seismic event, increasing its stability and preventing a potentially catastrophic load transfer from the wall to the frame. Francisco J. Pallarés, Ph.D., the principal researcher on the project, expl

ADDING STRUCTURAL supports to seismically retrofit reinforced-concrete buildings can be done in many ways. Kengo Kuma & Associates, an architecture firm based in Tokyo and Paris, has turned to an entirely new method in which the strength of the solution is concealed within lightweight strands of carbon fiber. Dubbed strand rods, the composite ropelike strands have been used to create latticelike, braced-frame interior bearing walls and an exterior support curtain that appears to delicately drape over the edges of the building. The strand rods were used to seismically retrofit a three-story, 40 m by 22 m building constructed in Nomi, Japan, in 1968. The rigid-frame, reinforced-concrete structure will now be used by the client, Komatsu Seiren, as a textile factory and will also have an experimental laboratory, according to Kengo Kuma, an architect and the founder of Kengo Kuma & Associates. Kuma wrote in response to written questions posed by Civil Engineering. The building w