Formed Steel Structure Design Of A Cold - WordPress
Design of a ColdFormed SteelStructureMay 30, 2018
Who Are We?Burak BağırganÖzgenur BaştuğUtku GürlerCan Özkan
Agenda01Introduction to Cold Formed SteelPreliminary Design What is cold formed steel and where is it used?What are the advantages?Architectural DesignLab Experiment02CostScheduleResources Cost EstimationScheduleResources Used in the Project03Structural Frame DesignModelling of the Structural System Modelling the frames with SAP2000C and U sections & section propertiesStructural modelling process04Earthquake, Dead & Live Load CalculationsCapacity Calculations Load calculationsDynamic properties (taken from SAP2000)Demand / shearCapacity calculations05Anchorage Design Outer Hold-downInner Hold-down
Cold Formed SteelVilla ProjectThe project aims to design a two-storey villa at aseismic belt. According to the project info theland is provided and the team only needs todesign the superstructure.Project Constraints:1.2.3.CostTimeSeismic belt
What is Cold Formed Steel? Cold formed steel (CFS) is a type of steel which ismade by rolling or pressing at relatively coldtemperatures. CFS members are produced using structuralquality sheet steel. No heat is required for its formation and variousthicknesses of steel frames are available forvarious uses. Cold-formed steel is generally used in theconstructions of residential buildings notexceeding 3 or 4 floors.
History of CFSCFS Around the World The use of CFS in construction began inthe 1850s. CFS is highly used in the USA,Scandinavian Countries, WesternEurope, Japan and Australia. First documented use of CFS: around1925. In 1920s and 1930s, limitedacceptance due to lack of adequatedesign standard. In the USA, CFS usage is 25% and inJapan this rate is 15% The usage of CFS in Turkey isbelieved to be limited to 0.5%
Advantages SustainabilityDurabilityCompactnessLightnessHigh strength and stiffnessEase of fabrication and applicationElimination of delaysEconomical transportation and handlingDisadvantages Thinner steel membersProne to local bucklingHigh unit priceLowfireresistance
Cost AnalysisThursdayFridayEstimated Cost: 500,000TL Cost of the projects for similarexisting projects are utilized. Accurate cost estimation is hard. It has comparatively low costvariance.
SchedulePreliminary DesignLiterature ReviewExperiment InvestigationArchitectural DesignStructural Member SelectionCost/ Schedule/ ResourceTODAY!Performance AssessmentDemand CalculationsCapacity CalculationsCapacity and Demand .05.201804.2018Engineering ProcessFrame Modelling withSAP2000Structural Modelling withSAP2000Load CalculationsFinal ReviewSecond IterationAnchorage DesignInspection of the ProjectReport
ResourcesFriday
Architectural Design Cold-formed steel panel dimensions: 1.2m x 2.4m(most common dimensions) Design constraints: Avoidance of excessive span lengths Comfortable and practical residential housingsystemPlan View
St37 grade steel nominal yield strength fy 227.5 MPanominal tensile strength ft 310.3 MPaLab ExperimentsLab experiments on cold formed steel made byAssoc.Dr.Serdar Soyöz and Burak Karabulut.Origin of our current projectSame structural material propertiesIn contrast with the experiment, linear analysis ismade.
Structural FrameModellingStructural frame modelled as: 1.2 x 2.4 m panel dimensions,taken from the standards C section outer studs, Csection mid-stud, U sectionlateral members 4 boards attached to theframe from 9 points Shear loads are not allowedon frame, shear is carried bythe sheathing material only.C SectionLateral displacement under force F 0.02 kN, thicknesst 25mmU Section
Modelling of the Structural System Replication of frames Box sections: Solution forwall corners! Slab members areinserted as masses ondiaphragm Box Section
Modelling of the Structural SystemModal Analysis Modal analysis uses the overall mass and stiffness of the structure tofind the various periods at which the structure will naturallyresonate.PeriodT 0.12It is also used to for detecting connection errors in a SAP2000 model.First ModeSecond ModeThird Mode
Performance AssessmentCapacity Demand!
Load CalculationsDead Load Calculations Board Weight (withrock wool) C-Section U-Section Slab WeightLive Load CalculationsLoad calculations are made according to TS498 andEarthquake Code (2007). The live load for residential buildings is takenas 2 kN/m2 from the code.Total Dead Load: 620.89 kNTotal Live Load: 725.26 kN
EarthquakeEarthquake LoadLoad Calculations:Calculations: Base Shear Force W: total weight of the building A(T): spectral acceleration coefficient Ra: earthquake load reduction coefficientLive Load Calculations: Spectral Acceleration Coefficient A0: effective ground acceleration coefficient I: building importance coefficient S(T): spectrum coefficient
Earthquake Load Calculations:
Earthquake Load Calculations: Total Earthquake Load: 320.61 kN Distribution of earthquake load to each storey
DemandCalculated loads are assignedto the model. Slabs have mass, therefore even if they are notmodeled, their weight must be assigned to themodel! Dead and live loads on slabs were distributed ontobeams using tributary area method. 1.2D 1.0Q 1.0Ex 0.3Ey & 1.2D 1.0Q 1.0Ey 0.3Exload cases are used.According to these loadings,Maximum demand for axial load:5.53 kNMaximum demand for shear load:6.41 kN
Capacity CalculationsLocal Column Buckling Flexural Buckling Torsional–FlexuralBuckling
Capacity CalculationsOverall Column Buckling Flexural Buckling Torsional-FlexuralBucklingSheathing Parameters from AISISpecification
Capacity CalculationsLocal Column BucklingOverall Column BucklingNominal & Allowed Load Calculations
Capacity CalculationsShear Capacity of FrameDesignMethod Characteristic strength of sheathing is taken as 5 kN/m. 2 sheathings with 1.2m width at each side are used ineach frame. Shear capacity of each frame is found to be 7.2 kN. LRFD method is used to calculate the design strength. Effective area is calculated by a multiplier methodpreviously used by MIT.EarthquakeASDΩ2,5LRFDΦ0,6
Anchorage - Outer Hold-down(M12 80 mm)Tensile Capacity Steel Failure CapacityDirectly calculated due to ETAG 000528.06 kN 25.87 kN Pull-out Failure CapacityDirectly calculated due to ETAG 0005Not decisive Concrete Cone FailureCalculated due to formulas given inETAG 001 & values given in ETAG000526.37 kN 25.87 kNShear Capacity Steel Failure CapacityDirectly calculated due to ETAG 000521.92 kN 8.8 kN Pull-out Failure CapacityDirectly calculated due to ETAG 000552.74 kN 8.8 kN
Anchorage - Inner Hold-down(M10 65 mm)Tensile Capacity Steel Failure CapacityDirectly calculated due to ETAG 000517.33 kN 16.33 kN Pull-out Failure CapacityDirectly calculated due to ETAG 0005Not decisive Concrete Cone FailureCalculated due to formulas given inETAG 001 & values given in ETAG000517.71 kN 16.33 kNShear Capacity Steel Failure CapacityDirectly calculated due to ETAG 000510.96 kN 8.8 kN Pull-out Failure CapacityDirectly calculated due to ETAG 000517.71 kN 8.8 kN
Capacity vs. DemandThe Most Critical StudCapacity ValuesDemand ValuesStud: 8.18 kNStud: 5.33 kNPanel: 7.2 kNPanel: 6.41 kNAnchorage: 26.37 kN (M12)Anchorage: 25.87 kN (M12)& 17.33 kN (M10)& 16.33 kN (M10)Capacity Demand!
Iteration It must be noted that these resultswere the consequence of acontinuous iteration process.The aim of the iteration was: To reach a more y(kN)20,828,18Demand(kN)7,35,33Web(mm)9950
Conclusion CFS is a relatively new application in Turkey and computer aided designof CFS is rather ambiguous. It was challenging to model and analyze a cold formed steel model,especially with limited software and application. Turkish Code did not even have CFS steel category until the latestrelease, it was treated as regular steel and modified with multipliers! Contemporary calculations are usually done by hand. New automated analysis methods are needed to streamline the CFSdesign process!The Deformed Shape Under Most CriticalLoading Case
References Cold-Formed Steel Design: AISI Manual. American Iron and Steel Institute, 2009.Design of Cold-Formed Steel Structures. ECCS, 2012.Karabulut, B., and S. Soyoz. “Experimental and Analytical Studies on Different Configurations ofCold-Formed Steel Structures.” Journal of Constructional Steel Research, vol. 133, 2017, pp. 535–546.,doi:10.1016/j.jcsr.2017.02.027.North American Standard for Cold-Formed Steel Framing: Lateral Design. American Iron and SteelInstitute, 2009.TS 498 - Yapı Elemanlarının Boyutlandırılmasında Alınacak Yüklerin Hesap Değerleri. Türk StandartlarıEnstitüsü, 1997.Deprem Bölgelerinde Yapılacak Binalar Hakkında Yönetmelik. Resmi Gazete, 2007.“Cold-Formed Steel Design”; Wei-Wen Yu and Roger A. LaBoube“Design of Cold-formed Steel Structures”; Dan Dubina, Viorel Ungureanu, Raffaele LandolfoETA-13/005: Torque-controlled expansion anchor for use in non cracked concrete, 2013.
Special thanks to our advisor Assoc.Prof. SerdarSoyöz for supporting us during our project.Thanks for listening.
Seismic belt. What is Cold Formed Steel? Cold formed steel (CFS) is a type of steel which is made by rolling or pressing at relatively cold temperatures. . North American Standard for Cold-Formed Steel Framing: Lateral Design. American Iron and Steel Institute, 2009.
formed steel, the fundamental theories of cold-formed steel design, advantages of cold-formed steel over other construction materials, cold-formed steel applications in today's construction market, and the connection methods. This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of course materials.
formed steel structure by reviewing the behavior, material properties, production methods, classification of cold formed steel elements. It also discusses the codes and guideline available for cold formed steel structure, important design criteria, connection, methods and durability issues based on some excellent researches.
STEEL STRUCTURE AND AAC PANEL WALL PAGE 17 PAGE 18 YUANDA NEW MATERIALS Steel Structure is formed by the main steel framework linking up H section, Z section and U section steel components, roof and walls using ALC and AAC panels, Sandwich Panels and other components such as windows, doors, cranes, etc. not only panels but also steel struture
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1.2.1 Steel Deck Institute (SDI) A. SDI C-2011, Standard for Composite Steel Floor Deck-Slabs B. SDI NC-2010, Standard for Noncomposite Steel Floor Deck C. SDI RD-2010, Standard for Steel Roof Deck 1.3 Definitions Accessories: Cold-formed steel components of the steel deck system other than the steel deck, which
Cold-Formed Steel Framing Seismic Design Optimization ii Phase 1a: Seismic Equivalency Parameter Evaluation PREFACE Currently, both wood structural panel and steel sheet sheathed, cold-formed steel framed and wood structural panel sheathed wood framed shear walls qualify for an R 6.5 in bearing
EN 1993-1-3 Design of steel structures: General rules: Supplementary rules for cold-formed members and sheeting EN 1993-1-4 Design of steel structures: General rules: Supplementary rules for stainless steels EN 1993-1-5 Design of steel structures: Plated structural elements EN 1993-1-8 Design of steel structures: Design of joints EN 1993-1-9 .
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