Steel trusses

1. STEELROOFS
Presentation By-Ar. Roopa Chikkalgi
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2. Use of trusses in buildings
•Trussesareusedinabroadrangeofbuildings,mainlywherethereisarequirementfor
verylongspans,suchasinairportterminals,aircrafthangers,sportsstadiumroofs,
auditoriumsandotherleisurebuildings.
•Trussesarealsousedtocarryheavyloadsandaresometimesusedastransferstructures.
•Thetrussesarewidelyusedtoservetwomainfunctions:
Tocarrytheroofload
Toprovidehorizontalstability.
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3. •Therearenumerousadvantagestousingsteeltrussesinsteadoftraditionalwoodtrussesbutthemain
reasonsaresimplicityandstrength.
•Someprefertousethemetalrooftrussbecausethebuildingofastructureisallaboutprecisionandmetal
hasamoreprecisemeasurementthanwood.
•Thesestrussesareextremelysimpletoinstall.
•Youneverhavetoworryaboutthemrottingordeterioratingfromtheweather.
•Youalsogetmoreusablespaceinsideyourbuilding.
WHY STEEL ROOF?
•Woodtrussesarelessexpensivetrusspertrussbutthey
requireyoutoinstallwoodheaders,thepostshavetobe
closertogetherandyouhavemoretrussestoinstall.
•Yougenerallyhavetoprotectthewoodfromtheweather.
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4. WHY STEEL ROOF?
•Prefabricatedsteeltrussesofferahigh-strength,
light-weightroofsystemthatcanbeinstalled
quickly.
•Inresidentialconstruction,woodtrussesstill
dominatetheindustry,whereadditionalstrength
isneeded,orwheregreaterfreespansare
requiredSteelroofsarepreferred.
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5. Advantages of Metal Roof Truss Structures
1.Even though they are considered to be more expensive, metal roof trusses can span further than
wood.
2.Metal roof trusses can be manufactured to exact standards.
3.They are much more lightweight and this allows for larger shipments. This reduces the time it takes
to get to the project site.
4.Metal roof trusses are fire resistant.
5.They are compatible with almost all types of roofing systems.
6.No insect infestations can occur.
7.Chemical treatments are not necessary to maintain the trusses.
8.Metal roof trusses are recyclable and therefore environmentally friendly.
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6. Disadvantages of Metal Roof Truss Structures
1.Skilled labor is required to install metal roof trusses.
2.They are not energy efficient since they allow more heat to escape from the structure.
3.Metal roof trusses allow sound to be more easily transmitted.
4.Temperature fluctuations allow them to move more.
5.When the metal is cut, drilled, scratched or welded, rust can become a problem.
6.The workers have a higher risk of electrocution when installing the metal roof trusses.
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7. Different types of Wooden and Steel Roof Trusses:
•King Post Truss
•Queen Post Truss
•Howe Truss
•Pratt Truss
•Fan Truss
•North Light Roof Truss
•Quadrangular Roof Truss
King Post Truss
•King Post Truss is a wooden truss.
•It can also be built of combination of wood and
steel.
•It can be used for spans upto8m.
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8. Queen Post Truss
•Queen Post Truss is also a wooden truss.
•It can be used for spans upto10m.
Howe Truss
•It is made of combination of wood and steel.
•The vertical members or tension members are
made of steel.
•It can be used for spans from 6-30m.
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9. Pratt Truss
•Pratt Truss is made of steel.
•Vertical members are tension and diagonal
members are compression.
•These are very economical form of roof trusses.
•It can be used for spans from 6-10m.
Fan Truss
•Itismadeofsteel.
•InFanTrusses,topchordsaredividedintosmall
lengthsinordertoprovidesupportsforpurlins
•Itcanbeusedforspansfrom10-15m.
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10. INTRODUCTION:
NORTHLIGHTTRUSSESARETRADITIONALLYUSEDFORSHORTSPANSININDUSTRIALWORKSHOP-TYPEBUILDINGS.THEY
ALLOWMAXIMUMBENEFITTOBEGAINEDFROMNATURALLIGHTINGBYTHEUSEOFGLAZINGONTHESTEEPER
PITCHWHICHGENERALLYFACESNORTHORNORTH-EASTTOREDUCETHESOLARGAIN.
NORTHLIGHT ROOF TRUSS
USES–
*ITISUSEDINWAREHOUSE,INDUSTRIES,FACTORIES,ETC.
*NORTHLIGHTTRUSSESARETRADITIONALLYUSEDFORSHORTSPANSININDUSTRIALWORKSHOP-TYPEBUILDINGS.
*THEYALLOWMAXIMUMBENEFITTOBEGAINEDFROMNATURALLIGHTINGBYTHEUSEOFGLAZINGONTHE
STEEPERPITCHWHICHGENERALLYFACESNORTHORNORTH-EASTTOREDUCETHESOLARGAIN.
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11. North Light Roof Truss
•When the floor span exceeds 15m, it is generally more
economicalto change from a simple truss arrangement to
one employing wide span which support trusses at right
angles.
•In order to light up the space satisfactorily, roof lighting has
to replace or supplement, side lighting provision must also
be made for ventilation form the roof.
•One of the oldest and economical methods of covering
large areas is the North Light.
•This roof consists of a series of trusses fixed to girders. The
short vertical side of the truss is glazed so that when the roof
is used in the Northern Hemisphere, the glazed portion faces
North for the best light.
•It can be used for spans from 20-30m.
•Used for industrial buildings, drawing rooms etc.
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12. Quadrangular roof Trusses
Quadrangular Roof Truss (for large spans)
•These trusses are used for large spans such as railway sheds and Auditoriums.
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13. TubularSteelTrussare used for large span constructions such as factories, industry worksheds, shopping
malls, huge exhibition centre, multiplexes etc. They are generally used for spans as large as 25-30m.
TUBULAR STEEL TRUSS:-
ADVANTAGES OF TUBULAR STEEL ROOF TRUSSES: -
•30%to40%lesssurfaceareathanthatofanequivalentrolledsteelshape.Therefore,
thecostofmaintenance,costofpaintingorprotectivecoatingsreduceconsiderably.
•Themoistureanddirtdonotcollectonthesmoothexternalsurfaceofthetubes.
Therefore,thepossibilityofcorrosionalsoreduces.
•Theendsoftubesaresealed.Asaresultofthis,theinteriorsurfaceisnotsubjectedto
corrosion.Theinteriorsurfacedonotneedanyprotectivetreatment.
•Theyhavemoretorsionalresistancethanothersectionoftheequalweight.
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14. Typical Steel Connections
SteelConnections
Manyconfigurationsareusedforforcetransferinconnections.Theconfigurationdepends
uponthetypeofconnectingelements,natureandmagnitudeoftheforces(andmoments),
availableequipment,fabricationanderectionconsiderations,cost,etc.
Rivets
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15. Bolts
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16. Gusset plate connections
•Gusset plates are usually either made from cold rolled or
galvanized steel based upon their use.
•Gussetplatesareusedforvariousstructures.Gussetplatesare
usedtoconnectbeamsandcolumnstogetherortoconnect
trussmembers.Theycanbeeithertheonlywayofconnecting
thebeamandcolumnsortheycanbeusedwithboltsand
welds.
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18. Presentation By-Ar. Roopa Chikkalgi
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19. Galvanized Steel Sheets (Plain and Corrugated)
•Galvanized iron (GI) sheets are steel sheets which are
basically coated with zinc and include a range of hot
dip galvanized and electro-galvanized steel sheets.
•Corrugated galvanisedironor steel is a building
material composed of sheets of hot-dip galvanised
mild steel, cold-rolled to produce a linear corrugated
pattern in them.
•The corrugations increase the bending strength of the
sheet in the direction perpendicular to the
corrugations, but not parallel to them. Normally each
sheet is manufactured longer in its strong direction.
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20. Galvanized CorrugatedSteel Sheets
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21. FIXING ACCESSORIES
J-Bolt
J-bolt, also called hook bolt, is a bolt in the form of letter “J” used to fix roof-sheathing or wall
sheathing to purlins and other structural members.
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22. INSTALLATION OF CORROGATED SHEETS
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