Structural engineering is a sub-discipline of civil engineering in which structural engineers are trained to design the 'bones and joints' that create the form and shape of human-made structures. Structural engineers also must understand and calculate the stability, strength, rigidity and earthquake-susceptibility of built structures for buildings and nonbuilding structures. The structural designs are integrated with those of other designers such as architects and building services engineer and often supervise the construction of projects by contractors on site. They can also be involved in the design of machinery, medical equipment, and vehicles where structural integrity affects functioning and safety. See glossary of structural engineering.
Rebar, 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.
A truss is an assembly of members such as beams, connected by nodes, that creates a rigid structure.
Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with recent experiences with large earthquakes near urban centers, the need of seismic retrofitting is well acknowledged. Prior to the introduction of modern seismic codes in the late 1960s for developed countries and late 1970s for many other parts of the world, many structures were designed without adequate detailing and reinforcement for seismic protection. In view of the imminent problem, various research work has been carried out. State-of-the-art technical guidelines for seismic assessment, retrofit and rehabilitation have been published around the world – such as the ASCE-SEI 41 and the New Zealand Society for Earthquake Engineering (NZSEE)'s guidelines. These codes must be regularly updated; the 1994 Northridge earthquake brought to light the brittleness of welded steel frames, for example.
A plate girder bridge is a bridge supported by two or more plate girders.
Steel frame is a building technique with a "skeleton frame" of vertical steel columns and horizontal I-beams, constructed in a rectangular grid to support the floors, roof and walls of a building which are all attached to the frame. The development of this technique made the construction of the skyscraper possible. Steel frame has displaced its predecessor, the iron frame, in the early 20th century.
A tied-arch bridge is an arch bridge in which the outward-directed horizontal forces of the arch(es) are borne as tension by a chord tying the arch ends rather than by the ground or the bridge foundations. This strengthened chord may be the deck structure itself or consist of separate, independent tie-rods.
A girder bridge is a bridge that uses girders as the means of supporting its deck. The two most common types of modern steel girder bridges are plate and box.
The I-35W Mississippi River bridge was an eight-lane, steel truss arch bridge that carried Interstate 35W across the Mississippi River one-half mile downstream from the Saint Anthony Falls in Minneapolis, Minnesota, United States. The bridge opened in 1967, and was Minnesota's third busiest, carrying 140,000 vehicles daily. After only 39 years in service, it experienced a catastrophic failure during the evening rush hour on August 1, 2007, killing 13 people and injuring 145. The National Transportation Safety Board (NTSB) cited a design flaw as the likely cause of the collapse, noting that an excessively thin gusset plate ripped along a line of rivets. Additional weight on the bridge at the time of failure was also cited by the NTSB as a contributing factor.
Steel Design, or more specifically, Structural Steel Design, is an area of structural engineering used to design steel structures. These structures include schools, houses, bridges, commercial centers, tall buildings, warehouses, aircraft, ships and stadiums. The design and use of steel frames are commonly employed in the design of steel structures. More advanced structures include steel plates and shells.
A Howe truss is a truss bridge consisting of chords, verticals, and diagonals whose vertical members are in tension and whose diagonal members are in compression. The Howe truss was invented by William Howe in 1840, and was widely used as a bridge in the mid to late 1800s.
The Mabey Logistic Support Bridge is a portable pre-fabricated truss bridge, designed for use by military engineering units to upgrade routes for heavier traffic, replace civilian bridges damaged by enemy action or floods etc., replace assault and general support bridges and to provide a long span floating bridge capability. The bridge is a variant of the Mabey Compact 200 bridge, with alterations made to suit the military user as well as a ramp system to provide ground clearance to civilian and military vehicles.
A pin and hanger assembly is used to connect two plate girders of a bridge. These assemblies are used to provide an expansion joint in the bridge. One beam is set on a pier with a short section cantilevered out toward the next pier. The other begins underneath the anchor span, and has its far end resting on the next pier. The beams have holes directly above each other. The two holes are connected using hangers, a pair of connecting plates sandwiching the bridge girders. A pair of large steel pins through the plates and girder webbing provide the hinges, holding up the suspended span while allowing it to move longitudinally. Large washers are bolted to each end of the pin to retain the hangers. Exceptionally long spans may have two sets of girders cantilevered from opposite bridge piers with a third set of girders suspended by pin and hanger assemblies from both cantilevers.
Section Beams are made of steel and they have a specific lengths and shapes like Ɪ-beam, 'L', C-channel and I flanged beam. These types of section are usually used in steel structures and it is common to connect them with plates of steel.
A steel plate shear wall (SPSW) consists of steel infill plates bounded by boundary elements.
Progressive collapse is the process where a primary structural element fails, resulting in the failure of adjoining structural elements, which in turn causes further structural failure.
In structural engineering, a pre-engineered building (PEB) is designed by a PEB supplier or PEB manufacturer with a single design to be fabricated using various materials and methods to satisfy a wide range of structural and aesthetic design requirements. This is contrasted with a building built to a design that was created specifically for that building. Within some geographic industry sectors pre-engineered buildings are also called pre-engineered metal buildings (PEMB) or, as is becoming increasingly common due to the reduced amount of pre-engineering involved in custom computer-aided designs, simply engineered metal buildings (EMB).
A bolt is an externally helical threaded fastener capable of being tightened or released by a twisting force (torque) to a matching nut. The bolt has an external male thread requiring a matching nut with a pre-formed female thread.
A buckling-restrained brace (BRB) is a structural brace in a building, designed to allow the building to withstand cyclical lateral loadings, typically earthquake-induced loading. It consists of a slender steel core, a concrete casing designed to continuously support the core and prevent buckling under axial compression, and an interface region that prevents undesired interactions between the two. Braced frames that use BRBs – known as buckling-restrained braced frames, or BRBFs – have significant advantages over typical braced frames.
Structural integrity and failure is an aspect of engineering that deals with the ability of a structure to support a designed structural load without breaking and includes the study of past structural failures in order to prevent failures in future designs.
