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Underground hard-rock mining refers to various underground mining techniques used to excavate "hard" minerals, usually those containing metals, such as ore containing gold, silver, iron, copper, zinc, nickel, tin, and lead. It also involves the same techniques used to excavate ores of gems, such as diamonds and rubies. Soft-rock mining refers to the excavation of softer minerals, such as salt, coal, and oil sands.
Rebar, known when massed as reinforcing steel or steel reinforcement, is a steel bar used as a tension device in 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 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.
Nondestructive testing (NDT) is any of a wide group of analysis techniques used in science and technology industry to evaluate the properties of a material, component or system without causing damage. The terms nondestructive examination (NDE), nondestructive inspection (NDI), and nondestructive evaluation (NDE) are also commonly used to describe this technology. Because NDT does not permanently alter the article being inspected, it is a highly valuable technique that can save both money and time in product evaluation, troubleshooting, and research. The six most frequently used NDT methods are eddy-current, magnetic-particle, liquid penetrant, radiographic, ultrasonic, and visual testing. NDT is commonly used in forensic engineering, mechanical engineering, petroleum engineering, electrical engineering, civil engineering, systems engineering, aeronautical engineering, medicine, and art. Innovations in the field of nondestructive testing have had a profound impact on medical imaging, including on echocardiography, medical ultrasonography, and digital radiography.
In engineering, a foundation is the element of a structure which connects it to the ground or more rarely, water, transferring loads from the structure to the ground. Foundations are generally considered either shallow or deep. Foundation engineering is the application of soil mechanics and rock mechanics in the design of foundation elements of structures.
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.
This page is a list of construction topics.
In construction or renovation, underpinning is the process of strengthening the foundation of an existing building or other structure. Underpinning may be necessary for a variety of reasons:
In materials science and solid mechanics, residual stresses are stresses that remain in a solid material after the original cause of the stresses has been removed. Residual stress may be desirable or undesirable. For example, laser peening imparts deep beneficial compressive residual stresses into metal components such as turbine engine fan blades, and it is used in toughened glass to allow for large, thin, crack- and scratch-resistant glass displays on smartphones. However, unintended residual stress in a designed structure may cause it to fail prematurely.
Delamination is a mode of failure where a material fractures into layers. A variety of materials, including laminate composites and concrete, can fail by delamination. Processing can create layers in materials, such as steel formed by rolling and plastics and metals from 3D printing which can fail from layer separation. Also, surface coatings, such as paints and films, can delaminate from the coated substrate.
Geotechnical investigations are performed by geotechnical engineers or engineering geologists to obtain information on the physical properties of soil earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions; this type of investigation is called a site investigation. Geotechnical investigations are also used to measure the thermal resistance of soils or backfill materials required for underground transmission lines, oil and gas pipelines, radioactive waste disposal, and solar thermal storage facilities. A geotechnical investigation will include surface exploration and subsurface exploration of a site. Sometimes, geophysical methods are used to obtain data about sites. Subsurface exploration usually involves soil sampling and laboratory tests of the soil samples retrieved.
Fiber-reinforced concrete or fibre-reinforced concrete (FRC) is concrete containing fibrous material which increases its structural integrity. It contains short discrete fibers that are uniformly distributed and randomly oriented. Fibers include steel fibers, glass fibers, synthetic fibers and natural fibers – each of which lend varying properties to the concrete. In addition, the character of fiber-reinforced concrete changes with varying concretes, fiber materials, geometries, distribution, orientation, and densities.
A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site.
A pile is a slender element cast in the ground or driven into it. Since pile construction as well as the final product are mostly invisible, engineers have often questioned their integrity, i.e. their compliance with project drawings and specifications. In fact, experience has shown that in piles, of all kinds flaws may occur. The purpose of integrity testing is to discover such flaws before they can cause any damage.
Dynamic load testing is a method to assess a pile's bearing capacity by applying a dynamic load to the pile head while recording acceleration and strain on the pile head. Dynamic load testing is a high strain dynamic test which can be applied after pile installation for concrete piles. For steel or timber piles, dynamic load testing can be done during installation or after installation.
High strain dynamic testing is a method of testing deep foundations to obtain information about their capacity and integrity, and in some cases, to monitor their installation. It is codified by ASTM D4945-12 - Standard Test Method for High-Strain Dynamic Testing of Piles.
A rebar spacer is a short, rod-like device used to secure reinforcing steel bars, or rebar, within cast assemblies for reinforced concrete structures. The rebar spacers are fixed before the concrete is poured and remain within structure.
Screw piles, sometimes referred to as screw-piles, screw piers, screw anchors, screw foundations, ground screws, helical piles, helical piers, or helical anchors are a steel screw-in piling and ground anchoring system used for building deep foundations. Screw piles are typically manufactured from high-strength steel using varying sizes of tubular hollow sections with helical flights.
The Franki piling system is a method used to drive expanded base cast-in-situ concrete (Franki) piles. It was developed by Belgian Engineer Edgard Frankignoul in 1909.
Thermal Integrity Profiling (TIP) is a non-destructive testing method used to evaluate the integrity of concrete foundations. It is standardized by ASTM D7949 - Standard Test Methods for Thermal Integrity Profiling of Concrete Deep Foundations.
References
- ↑ Hadjuk, Edward L.; Ledford, D.L.; Christopher, W.R. (2004). "PVC and Steel Access Tube Debonding during Sonic Logging Testing for the SC 170 Bridge Replacement Project". Proceedings of the Deep Foundation Institute 2004 Annual Conference, Vancouver, BC.
- 1 2 Schmauder, Gretchen; Steve D. Bowman; Thomas J. Adams (2006). "CROSSHOLE SONIC LOGGING: INSIGHTS ON TESTING NEVADA INFRASTRUCTUR" (PDF). Archived from the original (PDF) on 2011-08-10.
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- Farouz, E., Landers, P., Webster, S., November, 2005. Case History: Foundation Evacuation for the Virginia Highway 288 Project. GEO3 Construction Quality Assurance/Quality Control Technical Conference: Dallas/Ft. Worth, TX; 49-60.
- Beim, J.W., Debas, L.F., Kormann, A.C.M., Martinati, L.R., Neto, L.A., November, 2005. Tomography: A New Technology for Quality Control of Deep Foundations. GEO3 Construction Quality Assurance/Quality Control Technical Conference: Dallas/Ft. Worth, TX; 323-328.
- ASTM D6760 - 14 Standard Test Method for Integrity Testing of Concrete Deep Foundations by Ultrasonic Crosshole Testing, doi:10.1520/D6760-14
- ASTM D4428 / D4428M - 07 Standard Test Methods for Crosshole Seismic Testing, doi:10.1520/D4428_D4428M-07
