Innovative UHS Steel Material for Tension-Only Braced CFS Walls

2021 ◽  
Vol 873 ◽  
pp. 25-31
Author(s):  
Alessia Campiche

Lightweight Steel (LWS) systems, made of Cold Formed Steel (CFS) profiles, are widespread in seismic areas and often preferred to traditional systems. Improving structural performances in order to have higher building is now the goal, which could be achieved thanks to the use of steel innovative material. In particular, to increase the seismic performances of CFS buildings, the University of Naples “Federico II”, in cooperation with the Italian company Lamieredil S.p.A., has developed an innovative Lateral Force Resisting System (LFRS). The LFRS mainly consists of CFS frame (studs and tracks) braced by “V” shaped pre-tensioned Ultra High Strength (UHS) steel bars. The bracing was designed to be able to limit global displacement of structure, working as elastic spring, and to dissipate seismic energy by yielding. In order to prove the effectiveness of the new system, an extensive experimental campaign has been conducted. This paper focuses on material and component tests, describing tension tests on traditional materials and UHS steel, creep tests on UHS steel and nut-bar assembly tests.

Alloy Digest ◽  
2017 ◽  
Vol 66 (7) ◽  

Abstract Strenx Section 900 is a cold-formed steel section made of hot-rolled, high-strength steel with a minimum yield strength of 900 MPa (131 ksi). Its high strength combined with naturally stiff form enables construction of stronger and lighter structures. The common shape is a U-bend channel. This datasheet provides information on composition, physical properties, tensile properties, and bend strength as well as fracture toughness. It also includes information on forming, machining, and joining. Filing Code: SA-792. Producer or source: SSAB Swedish Steel Inc..


2021 ◽  
Vol 162 ◽  
pp. 107584
Author(s):  
Wenying Zhang ◽  
Xiangzhi Xu ◽  
Yang Liu ◽  
Cheng Yu ◽  
Xuechun Liu ◽  
...  

Author(s):  
S. D. Daymond ◽  
L. Rosenhead

The following theoretical investigation of the two-dimensional flow of an inviscid fluid past a keel and rudder, and of the consequent lateral force, follows experiments performed by Prof. T. B. Abell in the Department of Naval Architecture of the University of Liverpool, and we wish to acknowledge our indebtedness to him for the information given in many discussions.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Hui Chen ◽  
Jinjin Zhang ◽  
Jin Yang ◽  
Feilong Ye

The tensile behaviors of corroded steel bars are important in the capacity evaluation of corroded reinforced concrete structures. The present paper studies the mechanical behavior of the corroded high strength reinforcing steel bars under static and dynamic loading. High strength reinforcing steel bars were corroded by using accelerated corrosion methods and the tensile tests were carried out under different strain rates. The results showed that the mechanical properties of corroded high strength steel bars were strain rate dependent, and the strain rate effect decreased with the increase of corrosion degree. The decreased nominal yield and ultimate strengths were mainly caused by the reduction of cross-sectional areas, and the decreased ultimate deformation and the shortened yield plateau resulted from the intensified stress concentration at the nonuniform reduction. Based on the test results, reduction factors were proposed to relate the tensile behaviors with the corrosion degree and strain rate for corroded bars. A modified Johnson-Cook strength model of corroded high strength steel bars under dynamic loading was proposed by taking into account the influence of corrosion degree. Comparison between the model and test results showed that proposed model properly describes the dynamic response of the corroded high strength rebars.


2013 ◽  
Vol 378 ◽  
pp. 209-212
Author(s):  
Dong Gun Lee ◽  
Byunh Hyun Ahn ◽  
Je Hyun Lee ◽  
Uk Rae Cho ◽  
Bon Heun Koo

Al7075 alloy has typically good mechanical properties. Al7075 alloy has an ultimate tensile strength and yield strength, which is commonly used in the manufacturing of heavy-duty structures requiring good corrosion resistance and in applications requiring high strength to weight ratio, as well as good fatigue resistance. However, as compared to strength and corrosion of conventional steel material, it has some drawbacks. To overcome these disadvantages, Electrolytic plasma processing (EPP) was used. (EPP) is a novel electrochemical and physical surface treatment process for generating protective coatings on light metals. Because, these coating scan present high hardness and continuous barriers, it can offers good protection against abrasion, corrosion and heat as well as electrical insulation. The EPP treatments were carried out under a hybrid voltage of AC 200V (50Hz) combined with DC 260V power supply.


Author(s):  
Johannes Lechner ◽  
Jürgen Feix ◽  
Robert Hertle

<p>The Altstadtring-Tunnel is one of the essential east-west traffic routes in the city center of Munich and was constructed in the late 1960s. Segment 34 of the tunnel was built directly underneath the existing Prince-Carl- Palais, a historic building from 1804. Therefore 15 pre-stressed concrete girders with an effective depth of</p><p>3.5 m and a maximum span of up to 30 m were built which now form the tunnel roof slab. These girders were pre-stressed with steel nowadays well known for stress corrosion cracking. A recalculation of the slab showed that no ductile failure can be guaranteed in case of a progressive rupture of the tendons. Therefore, a concept for strengthening the slab was developed using concrete screw anchors as post installed bending and shear reinforcement. The concrete screw anchors are normally installed as anchoring elements in cracked and non- cracked concrete and are available with diameters up to 22 mm. Developing this concept further, it is straight forward to use these anchoring elements as post-installed reinforcement in existing concrete structures. This new strengthening system was developed at the University of Innsbruck in the last few years and can fulfill the special requirements of this project, such as installation of the strengthening system from underneath the tunnel slab during ongoing use of the structure. High strength steel with diameters of up to 63.5 mm will be used as post-installed bending reinforcement covered with a new shotcrete layer on the underside of the tunnel slab. In total 59.3 tons of new flexural reinforcement and 7199 concrete screws for strengthening the shear capacity of the girders will be used to ensure a ductile failure of the tunnel slab. The on-site work started in March 2019 and is expected to take two years to complete.</p>


2021 ◽  
Vol 885 ◽  
pp. 127-132
Author(s):  
Sarmad Shakeel ◽  
Alessia Campiche

The current edition of Eurocode 8 does not cover the design of the Cold-Formed steel (CFS) building structures under the seismic design condition. As part of the revision process of Euro-code 8 to reflect the outcomes of extensive research carried out in the past decade, University of Naples “Federico II” is involved in the validation of existing seismic design criteria and development of new rules for the design of CFS systems. In particular, different types of Lateral Force Resisting System (LFRS) are analyzed that can be listed in the second generation of Eurocode 8. The investigated LFRS’s include CFS strap braced walls and CFS shear walls with steel sheets, wood, or gypsum sheathing. This paper provides the background information on the research works and the reference design standards, already being used in some parts of the world, which formed the basis of design criteria for these LFRS systems. The design criteria for the LFRS-s common to CFS buildings would include rules necessary for ensuring the dissipative behavior, appropriate values of the behavior factor, guidelines to predict the design strength, geometrical and mechanical limitations.


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