dr. xianzhong zhao x.zhao@mail. - sals.org.cn · pdf filesteel structure: a structure which is...
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Lecture Questionnaire (1)Language preferred ( C = in Chinese, E = in English)
ECEC6
otherECCC7
EECC5ECEE4EEEC3EEEC & E2EEEE1
Tick the oneyou prefer
Coursework &written exam
Handout &textbook
Writing on theblackboard
OralPresentationNO.
From this course you prefer to:Learn steel struc. 1 2 3 4 5 6 7 Practisein English format English
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SyllabusAimsTo introduce procedures for designing steel members and connections.
Syllabus (total 41 courses)Introduction =>2Steel properties =>6Tension members =>3Compression members (Columns) =>7Bending Members (Beams) =>8Beam-columns =>7
Connections =>8
Coursework & AssessmentAssignment 1 Attendance, activities & Coursework 30%Assignment 2 Experiments EPUT 10%Assignment 3 Final written examination 60%
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IntroductionOutlines
what is steel structure?
why choose steel structures?
where & when use steel structures?
main structural types
state-of-the-art and prospective market
design concept & rationale of steel structures
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What’s steel structure?architecture → structure →steel structure
Architecture
Structure
Steel structure
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What’s steel structure?definition & scope
STEEL STRUCTURE: a structure which is made from organised combination of structural STEEL members designed to carry loads and provide adequate rigidity
Steel structure RC structurePK
steel structure, reinforced concrete (RC) structure, concrete-filled-steel tubular (CFT) structure, steel-RC composite structure?
steel shelfsteel furniture
……Steel structure? Yes, but
steelwork of buildings, bridges and civil eng. works in this course
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What’s steel structure?definition & scope
steel structures involve sub-structure or members in a buildingmade from structural steel
SHANGHAI STADIUMSteel roof + concrete stand
SHANGHAI GRAND THEATERSteel roof + concrete columns
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What’s steel structure?definition & scope
structural member（构件） is physically distinguishable part of structure with independent structural function, e.g. member (杆件)、element(板件)、cable(索) and their combination
cable
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Why use steel structure?advantages
High strengthThe high ratio of strength to weight (the strength per unit weight)
Excellent ductility and seismic resistanceWithstand extensive deformation without failure even under high tensile stress
Elasticity, uniformity of materialPredictability of properties, close to design assumption
Ease of fabrication and speed of erection
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high ratio of strength to weight
By M.F.Ashby
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Elasticity, ductility and uniformity of material
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Ease of fabrication and speed of erection
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Why use steel structure?disadvantages
Susceptibility to corrosionMaintenance costs / thin-walled structure
Loss of strength at elevated temperatureFireproofing costs
Susceptibility to bucklingSlender member in compression
Fatigue and brittle fracture
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Long-span structuresMulti-storey & high-rise buildingsBuildings of heavy duty plantsTower & mast structuresPortal framesBridgesInfrastructuresDeployable structuresGeneralized structures: mechanical
Where & when use steel structures?
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Long-span structuresAirport terminals
Stadiums
Exhibition centres
TheatresTrain stations
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High-rise buildings
Tai-bei 101
CCTV
World trade centre
Jinmao tower
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Buildings of heavy duty plant
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Tower & Mast structures
TV Tower Eiffel Tower TV Tower
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Portal frames
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Bridges
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Infrastructures
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Agricultural buildings
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Sight-seeing
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Deployable structures
Oh, he is coming…
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Generalized structures
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Main structural typesbuildings and bridges
truss structuresBar or truss members
frame structuresBeams and columns
grids structureslatticed structure or dome
arch
prestressed structures
beam bridge
truss bridgetruss members
arch bridge
cable-stayed bridge
suspension bridge
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Main structural typesbuildings: truss structures
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Main structural typesbuildings: frame structures
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Main structural typesbuildings: grid /domes
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Main structural typesbuildings: prestressed structures
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Main structural typesbuildings: prestressed structures
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Main structural typesbridges: truss bridges
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Main structural typesbridges: arch bridges
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Main structural typesbridges: cable-stayed bridges
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Main structural typesbridge: suspension structures
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State-of-the-art & prospective markettechnology & economy
technologyAccurate and automatic fabrication
economyLess construction time and less structural weight
environmentLess wet workReuse, Reduce & Recycle / removable
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State-of-the-art & prospectivemarket for steel structures
2007 y > overall output of the world before 1966
2008 y > 2nd-8th output
0
100
200
300
400
500
600
China Japan America Russia India Korea Germany Ukraine
Raw
stee
l ou
tput
, Mt
2007 2006 2005 2004 2003
8
7
6
5
4
3
2
42.8Ucran
48.5Germany
51.4Korea
53.1Italy
72.7Russia
97.2USA
120.2Japan
485.9Sum.2~8
Output/MtNationsNo.
489.2China1
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State-of-the-art & prospectivemarket for steel structures
Crude steel consumed kg/head
Forecast average2017 = 550kg/head
2007-2017
750
450
360
Coastal
Central
Western
Regional Kg/head 2006
434
227
170
Coastal
Central
Western
Kg/head 2017
National average2007 = 340kg/head
Data: CRU, NBS, CISA
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State-of-the-art & prospectivemarket for steel structures
中国建筑业房屋竣工面积
2004128163
200080715
0
20000
40000
60000
80000
100000
120000
140000
1985 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004
万平米
Steel structure 2%→4%
0
50,000
100,000
1960 1970 1980 1990 2000
Ｋ㎡
Wooden
Steel
R.C
SteelR.COthers
year
steel structureR.C structure
M/ton
↑JAPAN↓CHINA steel used in buildings
Residential Housing
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Design concept & rationaleensure strength, stability and stiffness
StiffStrengthstabilityLight
All OK !
Not stiff enough (need bigger E)
Not strong enough (need bigger σy )
Not stable enough
Too heavy (need lower ρ)
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Design concept & rationale
metallurgySteel
fabrication
Member + connectionerection
structural system
Loads
action
Strength, stability , rigidityForce, deformation
S ≤ RPerformance required:Safety, serviceability, durability
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Design concept & rationaleLoads
action
structuralmodel
elementmember
restraintconnection
loadingactions
?
?
?
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Design concept & rationaleelementmember
restraintconnection
loadingactions
?
?
?
Analytical model
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Design concept & rationaleLoads
action
force
deformation
Mechanics of materialsStructural analysisElastic mechanicsPlastic mechanics
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Design concept & rationale
metallurgySteel
fabrication
Member + connectionerection
structural system
Loads
action
Strength, stability , rigidityForce, deformation
S ≤ RPerformance:Safety, serviceability, durability
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Design concept & rationale
metallurgySteel
fabrication
Member + connection
Strength, stability , rigidity
Mechanics of materialsYou got a high level?
Tension memberCompression memberBeamBeam-columnconnection
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Design concept & rationale
S≤R fR
R
fs
S
RaRnSa Sn
Sn Rn
objective
Rd-Sd0
Sn≤Rn
Sn RnSd≤Rd
subjective
Acceptable:point of view of safety
point of view of economy
fR-S
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Design concept & rationale
RaSa Sn Rn
DESIGN METHOD
— ASD
— LRFD
∑ψSn≤Rn/K
∑γSψSn≤Rn/γR
fd
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Design concept & rationale
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brittle / ductile fracture of steel members or connectionsglobal buckling of structures/memberslocal bucklingexcessive development of plastic deformationloss of geometry stabilityfatigue failure
possible failure modes
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brittle / ductile fracture of steel members or connections
possible failure modes
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global buckling of structures/members
possible failure modes
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local buckling
possible failure modes
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excessive development of plastic deformation
possible failure modes
原试件 MCP-1 MPP-1
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loss of geometry stabilityfatigue failure
possible failure modes
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your task:Prevent all these failure modes
possible failure modes