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Structural Steel
Published in Fiona Cobb, Structural Engineer’s Pocket Book, 2020
Weathering steels are high strength, low alloy, weldable structural steels which form a protective rust coating in air that reaches a critical level within 2–5 years and prevents further corrosion. Cor-ten is the Corus proprietary brand of weathering steel, which has material properties comparable to S355, but the relevant material standard is BS EN 10155. To optimize the use of weathering steel, avoid contact with absorbent surfaces (e.g. concrete), prolonged wetting (e.g. north faces of buildings in the UK), burial in soils, contact with dissimilar metals and exposure to aggressive environments. Even if these conditions are met, rust staining can still affect adjacent materials during the first few years. Weathering bolts (ASTM A325, Type 3 or Cor-ten X) must be used for bolted connections. Standard black bolts should not be used as the zinc coating will be quickly consumed and the fastener corroded. Normal welding techniques can be used.
Ferrous and non-ferrous metals
Published in Arthur Lyons, Materials for Architects and Builders, 2019
Weathering steels are structural steels that have been alloyed with small proportions of copper, usually between 0.25% and 0.55%, together with silicon, manganese, chromium and phosphorus. Additional minor constituents are combinations of aluminium, niobium, vanadium and titanium (BS 7668: 2016 and pr EN 10025-5: 2018). The alloying has the effect of making the naturally formed brown rust coating adhere tenaciously to the surface, thus preventing further loss by spalling. All weathering steel must be carefully detailed to ensure that the rainwater run-off does not impinge on other materials, particularly concrete or glass where it will cause severe staining during the first few years of exposure to the elements. Cor-Ten® is the commercial name for weathering steels. Table 5.9 gives the steel specification and steel number to the British Standard. Weathering steels are used for structural and cladding applications, as well as for sculptural works of art (Fig. 5.17).
Design of CFDST Columns
Published in Lin-Hai Han, Dennis Lam, David A. Nethercot, Design Guide for Concrete-Filled Double Skin Steel Tubular Structures, 2018
Lin-Hai Han, Dennis Lam, David A. Nethercot
1.When the structure is exposed to the environments that have special requirements for corrosion prevention or is subjected to corrosive gaseous and solid mediums, weathering steel should be used.
NaCl and Na2SO4 solution effect on weathering steel visual appearance when the ambient temperature changes cyclically
Published in Cogent Engineering, 2019
Mindaugas Daukšys, Evelina Bitautaitė, Jūratė Mockienė, Dalia Nizevičienė
The protection ability inherent in weathering steel can be affected by the environment in different kind of atmospheric particles rich urban atmospheres (Aramendia, Gómez-Nubla, Castro, & Madariaga, 2014). The presence of atmospheric particles of calcium carbonate does not have a significant negative role in the metal decay process. However, the presence of high magnesium calcite plays an important role in the formation of magnesioferrite, another deleterious product present in the surface of the weathering steel. As all these sulphates are soluble, rain water can dissolve them leading into a continuous decaying and material loss process. Other atmospheric particles such as calcite, charcoal, and chromium rich particles were detected together with several compounds produced in the reaction of steel and deposited particles with acid gases of the atmosphere (Aramendia, Gomez-Nubla, Castro, & Madariaga, 2015b; Nishimura et al., 2000). These particles have a negative effect on the conservation of weathering steel because the change the visual appearance of steel surface and decrease its resistance to atmospheric agents. Chiavari et al. (2012) concluded that pre-patination had no beneficial effects on corrosion of Cor-Ten with different surface finish. Corrosion rate of weathering steel is considerably lower than that of the standard carbon steel. Nevertheless, the possible effect of corrosion on reliable service of the structure throughout the designed service life should be considered when designing the structures (Křivý, 2012; Křivý & Konečný, 2013; Urban, Krivy, & Kreislova, 2015).
He kōrero takiwā, he takiwā korero/Stories within Spaces, Spaces Defined by Stories: A Footbridge Design Concept for New Zealand
Published in Structural Engineering International, 2018
Ana Isabel Sarkis Fernandez, Gabriele Granello, Royce Liu, Claudio Cappellaro, Alessandro Palermo, Paul Millar
In terms of maintenance and durability, the corrosion rate of weathering steel is very low, such that bridges fabricated with unpainted weathering steel can achieve a design life of up to 120 years with only nominal maintenance (maintenance such that the system is capable of achieving a time to first maintenance of at least 40 years, unless agreed otherwise with the road-controlling authority).12 Moreover, the bridge is located in a Category C3 environment,13 which indicates a medium atmospheric corrosivity, the level for which the use of unpainted weathering steel is recommended.14 Hence, a well-detailed weathering steel bridge in an appropriate environment provides an attractive, low-maintenance solution.
Structural Performance and Engineering Application of a Long Lasting Weathering Steel Composite Bridge with Tubular Flanges
Published in Structural Engineering International, 2022
Chun-sheng Wang, Jing-wen Zhang, Lan Duan, Xiao-liang Zhai, Yi-wei Wang
To achieve the aim of life cycle economics, the life cycle cost of bridge engineering should be evaluated. By comparing the life-cycle costs of a weathering steel bridge with a traditionally coated steel bridge, the coating and maintenance costs were the key components of the cost and cost savings could be made by adopting a weathering steel bridge design. What’s more, the uncoated design realised the energy conservation and environmental protection requirements.