SYLLABUS

SYLLABUSUNIT IIntroduction: Loads, structural steels and their specifications, structural elements, steel vs. concrete and timber, design approacheselastic and limit state methods, design specifications as per IS: 800, structural layout, strength and stiffness considerations, efficiency of cross-section, safety and serviceability considerations.

Structural Fasteners and Connections: Riveting and bolting, their types, failure of riveted joint, efficiency of a joint, design of riveted joint, concentric riveted joints, advantages and disadvantages of bolted connections, stresses in bolts, types of welded joints, design of welded joint subjected to axial loads, welded joints subjected to eccentric loads, simple, semi-rigid and rigid connections.

UNIT IITension Members: Types of sections, net area, net effective area for angles, tees, design of tension members, tension splice, high strength steel cables.

Compression Members: Axially loaded columns, effective length, slenderness ratio, allowable stresses, general specifications, design of axially loaded members, laced and battened columns and their design, built up compression members, eccentrically loaded columns and their design, column splice and its design, encased columns.

UNIT IIIFlexural Members: Design criteria, permissible stresses, laterally supported beams and their design laterally unsupported beams and their design, web buckling, web crippling, built up beams, encased beams, members subjected to bending and compression, Plate Girders: Introduction, weight and economic depth, design of flanges, design of web, curtailment of flange plates, intermediate and bearing stiffeners, design of a riveted and welded plate girders, web and flange splice.Column Bases: Introduction, slab base, gusseted base, column base subjected to moment, grillage foundation.

UNIT IVTubular Structures: Permissible stresses, tube columns and compression members, tube tension members, tubular roof trusses, joints in tubular trusses, tubular beams and purlinsAluminium Structures: Permissible stresses, tension members, compression members, local buckling of compression members, design of beams and connections

Text Books/Reference Books

Design of Steel Structures, Vol. 1 and Vol. II, Ram Chandara, Standard Book House.Design of Steel Structures, L.S NEGI, Tata McGraw Hill, New Delhi.Design of Steel Structures, S. Ramamrutham and R Narayana, Dhanpat Rai PublicationDesign of Steel Structures, by A.S. Arya and J.L. Ajmani. , Nem Chand Brothers, Roorkee.1.Design of Steel Structures, P. Dayaratnam, Wheeler Publishing, New Delhi.2.Design of Steel Structures, M. Raghupathi, Tata McGraw Hill, New Delhi.

CODES Code of practice for general construction in steel IS 800-1984Handbook for structural engineersSP6(1)-1964Code of practice for design loads (other than earthquake) for building and structures : IS 875(Part I-IV) : 1987IRC for vehicle load in bridge structures INTRODUCTIONWHAT ARE STEEL STRUCTURES ?

A structure which is made from organised combination of structural STEEL members designed to carry loads and provide adequate rigiditySteel structures involve a sub-structure or members in a building made from structural steel. Some famous steel structures are-

WALT DISNEY CONCERT HALL,US

TYNE BRIDGE,UK

HOWRAH BRIDGE,INDIA ADVANTAGES OF USING STEEL IN STRUCTURESLighter, High strength, Faster to erect, High scrap value The high ratio of strength to weight (the strength per unit weight) Excellent ductility and seismic resistance Withstand extensive deformation without failure even under high tensile stress. Elasticity, uniformity of material Predictability of properties, close to design assumption Ease of fabrication and speed of erectionRecyclable material

MOST IMPORTANTSteel structures facilitate ease of fabrication and faster erection of structure .Bolts and welding employed for joining .

DISADVANTAGES OF USING STEEL IN A STRUCTURESusceptibility to corrosionMaintenance costs / thin-walled structureLoss of strength at elevated temperatureFireproofing costs Susceptibility to bucklingFatigue and brittle fractureSkilled labor required

Buckling phenomenonLOADSDEAD LOAD(IS 875 Part I)

LIVE LOADS(IS 875 Part II)- Earth pressure, Water current load, Impact load and thermal loads

Environmental loads- Wind load(IS 875 Part III), Seismic loads(IS 1892:2002), Snow load, Rain load Where & when use steel structures?1) Long-span structures2)Multi-storey & high-rise buildings3) Buildings of heavy duty plants4)Tower & mast structures5)Portal frames6)Bridges7)Infrastructures8)Deployable structures9)Generalized structures: mechanicalSTRUCTURAL STEEL SECTIONSRolled Steel Angle Sections (ISA)Rolled steel Tee sections (IST)Rolled Steel Channel Sections(ISC)Rolled Steel I Sections(ISB)Indian Standard junior beam (ISJB)Indian Standard Light Beam (ISLB)Indian Standard Medium Beam (ISMB)Indian Standard Wide Flange Beam (ISWB)Indian Standard Heavy Beam (ISHB)Indian Standard Flats (ISF)Rolled Steel Plate Section ( ISPL)Rolled Standard Sheet Sections (ISSH)Indian Standard Strips (ISST)Rolled Steel TubesIndian Standard Round Bars (ISRO)Indian Standard square bars (ISSQ)13

Elements of cross section16

Elements of cross section

17MECHANICAL PROPERTIES OF STEELModulus of Elasticity(E)= 2x10^5 N/sqmmShear Modulus(G)=0.769 x 10^5 N/sqmmPoissons ratio()=Elastic range=0.3Plastic range=0.5Coefficient of thermal expansion = 12x10^-6/Degree Celsius

Design PhilosophiesWorking Stress Design (WSD)

Plastic Design (PD)

Limit State Method (LSM)

21Working Stress DesignService loads are calculated as expected during service life.Linear elastic analysis is performed.A factor of safety (FOS) of the material strength is assumed (usually 3-4)

Design is satisfactory if (maximum stress < allowable stress)LimitationsCase specific, no guarantee that our design covers all casesArbitrary choice of FOS?!

22Plastic DesignService loads are factored by a load factor.The structure is assumed to fail under these loads, thus, plastic hinges will form under these loads Plastic Analysis.The cross section is designed to resist bending moments and shear forces from the plastic analysis.Members are safe as they are designed to fail under these factored loads while they will only experience service loads.LimitationsNo FOS of the material is considered, neglecting the uncertainty in material strength!Arbitrary choice of overall FOS?!23Stress-strain curveStandard Plain Carbon Steel

Yield plateauFyStrain eStress fFuENecking & FractureStrain HardeningElasticLimit State Method of design (LSM)LSM is similar to plastic design which considers most critical limit states of strength and serviceability.Service loads are multiplied by load factors (g) and linear elastic analysis is performed.Material strength is reduced by multiplying the nominal material strength by a resistance factor (f)The design rule is: Design Action