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International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181Vol. 1 Issue 5, July - 2012Ms. Darshana P. ZoadDepartment of Civil Engineering Karmaveer Dadasaheb Kannamwar College of Engineering,Nagpur 440 009Evaluation Of Pre-Engineering Structure Design By IS-800 As AgainstPre-Engineering Structure Design By AISCwww.ijert.org1

International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181Vol. 1 Issue 5, July - 2012AbstractTechnological improvement over the year hascontributed immensely to the enhancement ofquality of life through various new products andservices. In structural Engineering, apart fromstructural and aesthetic design requirements, themajor hurdle was the rate of construction and thesafety norms. Development of Pre-EngineeringStructure (PES) accelerated the rate ofconstruction maintaining all the safety factorsreducing the erection time of the structure. PES hasalso been satisfying a wide range of aesthetic andstructural design requirements. Thus PES fulfilswide range of building configurations, customdesigns, requirements and applications.India being one of the fastest able. Thus there is wide scope of PES inIndia. As compared to other countries Indian codesfor building design are stringent but safer. Thus,PES being an upcoming field in constructionindustry in India, it becomes necessary to study thePES design using IS 800 over AISC, which isdiscussed further.IntroductionIn the USA, where the PES concept wasoriginally conceived during the early years of thiscentury, nearly 70% of all single storey nonresidential construction now utilizes pre-engineeredStructures. Applications range from small carparking sheds to 90 m ( ), wide clear span aircrafthangars to low-rise multi-storey buildings. Almostevery conceivable building use has been achievedusing the pre-engineered structure approach.past 50 years. These advantages include: LowInitial Cost, Superior Quality, Fast ProjectConstruction, Functional Versatility, ArchitecturalFlexibility, Low Maintenance and OperatingCosts.[1]-[1]Source: Z. Steel Tech. manualPre engineered steel buildings can be fittedwith different structural accessories includingmezzanine floors, canopies, fascias, interiorpartitions etc. and the building is made water proofby use of special mastic beads, filler strips andtrims. This is very versatile buildings systems andcan be finished internally to serve any functionsand accessorized externally to achieve attractiveand unique designing styles. It is veryadvantageous over the conventional buildings andis really helpful in the low rise building design.Pre engineered buildings are generally low risebuildings however the maximum eave height cango upto 25 to 30 metres. Low rise buildings areideal for offices, houses, showrooms, shop frontsetc. The application of pre engineered buildingsconcept to low rise buildings is very economicaland speedy. Buildings can be constructed in lessthan half the normal time especially whencomplemented with the other engineered subsystems.[2]- [2]Source: Civil engineering portal(http://www.engineeringcivil.com)Stability Approach: Pre-engineeredbuilding (PEB)Metal Building, A SystemUntil 1990, the use of pre-engineered structurewas confined mostly to North America and theMiddle East. Since then, the use of pre-engineeredstructures has spread throughout Asia and Africawhere the PES construction concept has now beenwidely accepted and praised. A growing number ofprominent international contractors and designers,who previously specified conventional structuralsteel buildings exclusively, have recently startedusing the pre-engineered building approach. Theynow enjoy significant cost savings and benefitsfrom the faster construction cycle resulting fromthis concept. From excavation to occupancy noother building system matches the pre-engineeredbuilding system when it comes to speed and value.The advantages of pre-engineered steel buildingsare numerous and are the major reason for thespectacular growth of the PES industry during thewww.ijert.orgIn PEB, the components such as walls, roof,main and secondary framing, and bracing aredesigned to work together. That’s why it isalso called as metal building system as itsatisfies the classical definition of a system asan interdependent group of items forming aunified whole.A building’s first line of defense against theelements consists of the wall and roofmaterials. These elements also resist structuralloads, such as wind and snow, and transfer theloads to the supporting secondary framing.The secondary framing—wall girts and roofpurlins—collects the loads from the wall androof covering and distributes them to the mainbuilding frames, providing them with valuablelateral restraint along the way.The main structural frames, which consist ofcolumns and rafters, carry the snow, wind, and2

International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181Vol. 1 Issue 5, July - 2012oother loads to the building foundations. Thewall and roof bracing provides stability for thewhole building Even the fasteners are chosento be compatible with the materials beingsecured and are engineered by themanufacturers.--Stability approachAs loads on the building are applied in bothvertical as well as in lateral and longitudinaldirection, we have to make building stable in alldirections. Vertical support for the whole buildingis provided by Main frame. It also provides lateralstability for the building in its direction whilelateral stability in other direction is achieved by abracing system.Part 5 Special Loads and OtherLoad CombinationIS1893 Part I Criteria for EarthquakeResistant Design Of Structures. Part I.General Provisions and Buildings.Design of structural steel i.e. built up andhot rolled section is govern by IS800:Code of Practice for General Constructionin SteelStructural loadsDifferent structural loads that the building typicallymust carry are- Dead load- Collateral load- Live load- wind load- Seismic loadForces that act vertically are gravity loads likedead load, collateral load, live load. Forces that acthorizontally, such as stability, wind and seismicevents require lateral load resisting systems to bebuilt into structures. As lateral loads are applied toa structure, horizontal diaphragms (floors androofs) transfer the load to the lateral load resistingsystem.Building ParameterBuilding under consideration for the captionedproject is as follows:Clear span BuildingBuilding dimensions Width 25.8m Length 56.0m Clear ht 7.0m Bay spacing 7.0m 2.5m brick wall along the peripheryof building. 1:10 slopeWind speed 39 m/secSeismic zone IIDesign CodesAmerican codes- Code which governs load calculation is,MBMA (Metal Building ManufacturersAssociation), Low Rise Building SystemsManual- Code which governs the design of hotrolled section & build up component is,AISC (American Institute Of SteelConstruction), Manual Of SteelConstruction, Allowable Stress Design.Indian codes- Design load calculation by IS 875(PART ITO V) and IS 1893.- IS 875: Code Of Practice For DesignLoads (Other Than Earthquake) ForBuildings and Structures.o Part 1 Dead loado Part 2 Imposed loado Part 3 Wind Loado Part 4Snow loadLoad calculation by IS 875 & IS 1893Dead Load Calculation: Along with selfweight, we have to add Imposed dead load due tosecondary elements like roof sheeting, purlins etc.Consider dead load for 0.5 mm Panel andsupporting purlin 0.15 KN/m2We must also add general collateral load i.e. onlyfor Lighting 0.05 KN/m2Dead Load (0.15 0.05) x 7.0 (Tributary 7.0 m) 1.40 kn/mwww.ijert.org3

International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181Vol. 1 Issue 5, July - 2012K2 0.82Live load calculation: (IS: 875 (Part 2) -1987)Live load includes all loads that the structure issubjected to during erection, maintenance andusage throughout the life time of the structure.From Table 2 of IS: 875 (Part 2) for flat, sloping or curved roof with slopes up to and including 10 degrees when Access not provided except formaintenanceLive Load 0.75 KN/m2 0.75 x 7.00 5.3 kn/m(Tributary 7.0 m)Wind loads calculation: ( IS : 875 (Part 3) –Design wind speed (Vz) Vb x K1 x K2 x K3(Clause 5.3) where,K1Probability factor (risk coefficient)K2Terrain, height, and structure size factorK3Topography factorUpwind slope 3Upwind slope 3(Clause 5.3.2.1)K3 1.0K3 1.0 to 1.36K3 1.0Design wind speed,Vz V b x K 1 x K 2 x K 3Vz 44 x 1.0 x 0.82 x 1.0Vz 36.08 m/sec(Clause 5.4)Wind load on individual members,F (Cpe-Cpi)* A* Pd(Clause 6.2.1)whereCpe external pressure coefficient,Cpi internal pressure coefficientA surface area of structural elementPd design wind pressureProbability factor / Risk coefficient (K1)- Class of structure - All general buildings &structuresMean probable design life of structures - 50yrsBasic wind speed- 44 m/secNow we have to find Cpi and Cpe :(Table 1 of IS : 875 (Part 3))Terrain, height, and structure size factor (K2)K2 depends upon terrain category, class of structureand height of structureTerrain categoryTopography factor (K3)Design Wind Pressure,Pz 0.6 Vz2Pz 0.6 (36.08)2Pz 0.7181987)Basic wind speed (Vb) 44 m/secK1 1.0(Table 2 of IS : 875 (Part 3))(Clause 5.3.2.1)Internal Pressure Coefficients (Cpi) Enclosed 0.2(Clause 6.2.3.1) Partially enclosed 0.5(area bet 5 to 20%) 0.7(area more than 20%)(Clause 6.2.3.2)Internal Pressure Coefficients (Cpi) 0.2External Pressure Coefficients (Cpe) H/W 8 / 25.8 0.31 (H/W ½) L/W 56 / 25.8 2.17 (3/2 L/W 4) Roof angle 5.71The building under consideration falls under –Category 3Class of structure(Clause 5.3.2.2)Depends upon diamension i.e. greatest horizontalor vertical dimension of Structures and/or theircomponentsClass ADiamension 20mClass BDiamension 20m-50mClass CDiamension 50mDimension represents maximum horizontal orvertical dimension of structure and /or theircomponents.Coefficients for wall(Table 4-IS: 875 (PART 3))Wind angle 00The building under consideration falls under:Class C (as 56.0 m 50 m)Height of structure: Eave ht. 8.0 mm ( 10 m)Hence, Height 10.0 mwww.ijert.org4

International Journal of Engineering Research & Technology (IJERT)ISSN: 2278-0181Vol. 1 Issue 5, July - 2012-0.8-0.6 0.7 /- 0.2-0.8-0.25Different wind load casesWL1-0.6WL1Wind angle 0 0.2 internal pressure coefficientwind from left.Wind angle 900WL2Wind angle 0 0.2 internal pressure coefficientwind from right 0.7WL3-0.5 /- 0.2Wind angle 0- 0.2 internal pressure coefficientwind from left.-0.5WL4Wind angle 0- 0.2 internal pressure coefficientwind from rightWL5Wind angle 90 0.2 internal pressure coefficientwind in ve z- direction-0.1Coefficients for roof (Table5 of IS: 875WL6Wind angle 900 0.2 internal pressure coefficientwind in -ve z- direction(PART 3) )Wind angle 00-0.94WL7Wind angle 90-0.2 internal pressure coefficientwind in ve z- direction-0.4WL8Wind angle 90- 0.2 internal pressure coefficientwind in -ve z- directionFinal wind coefficients for different wind cases(Cpe-Cpi):Wind angle 900WL1Left ColumnLeft RafterRight RafterRight .00-1.00-0.70-0.70-1.00-1.00-0.70Final wind pressure for different wind caseswww.ijert.org5