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EAT-354 (STEEL BUILDING DESIGN). PREPARED BY SHAMILAH ANUDAI@ANUAR. CONCRETE VS STEEL. INTRODUCTION. Steel is a man-made metal containing 95% or more iron . Steel, as a building material has been used extensively in various types of structures
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EAT-354(STEEL BUILDING DESIGN) PREPARED BY SHAMILAH ANUDAI@ANUAR
INTRODUCTION • Steel is a man-made metal containing 95%ormore iron. • Steel, as a building material has been used extensively in various types of structures • The formation of steel structure in various shapes and forms utilized to support loads andresist the various forcesto which the structures are able to function properly.
CONT… • Steel is the most widely used metal as a construction material. • Its popularity is due to the combination of several factors such as high strength, durability, good ductility, high stiffnessandrelatively cheap if the speedy in construction time is taken into account.
CONT… • Basic shape of steel mill are plate, section and bars which are fabricate to form beams, girders, columns, struts, tiesand etc.
Type of Steel • Dead Mild steel (contain < 0.15% carbon) • Mild Steel (contain 0.15 – 0.30% carbon) • Medium Carbon Steel (0.30 – 0.80% carbon) • High Carbon Steel (0.80 – 1.50% Carbon) • Cast Steel/Carbon Tool Steel (contain >1.50% carbon)
Mild Steel • Ductile and malleable • More tough and elastic than cast iron • More prone to rusting than wrought iron • Corrodes quickly • Withstand shocks and impacts well • Equally strong in tension, compression and shear • Difficult to harden and temper • Used as rolled structural sections such as I-section, T-section, Channel section, Angle irons Mild Steel Bars Mild Steel Channels
Medium Carbon Steel • Granular structure • More tough and elastic than mild steel • Easier to be tempered as compare with mild steel • More difficult to forge and weld • Stronger in compression than in tension or in shear • Withstand shock and vibration better
High Carbon Steel • Increased tensile strength leads to less weight of it being used as compared to Mild and medium steel • Structure becomes lighter • Good in corrosion resistance • Tougher and more elastic • More brittle and less ductile than mild steel • Use in reinforcing pre-stressed concrete structures High Tensile Steel Bars High Tensile Steel Rods
Advantages of Steel • High strength • The high ratio of strength to weight (strength per unit weight) • Excellent ductility and seismic resistance • Withstand extensive deformation without failure even under high tensile stress • Elasticity, uniformity of material • Ease of fabrication and speed of erection
Disadvantages of Steel • Susceptible to corrosion • Maintenance costs/thin-walled structure • Loss of strength at elevated temperature • Fireproofing costs • Susceptibility to buckling • Fatigue and brittle fracture
The application of Steel • Long-span structures • Multi-storey and high-rise buildings • Buildings of heavy duty plants (Eg: Heavy Industry factory) • Tower and mass structures (Eg: Frame system • Portal frames • Bridges • Infrastructures
Designer Consideration • The initial cost which includes fees, site preparation, cost of materials and construction. • Maintenance costs (e.g. decoration and structural repair). • Insurance chiefly against fire damage. • Eventual demolition.
Classification of cross-section in accordance to EC3 • Class 1cross-sections are those which can form a plastic hinge with the rotation capacity required from plastic analysis without reduction of the resistance. • Class 2cross - sections are those which can develop their plastic moment resistance, but have limited rotation capacity because of local buckling. • Class 3cross-sections are those in which the stress in the extreme compression fibre of the steel member assuming an elastic distribution of stresses can reach the yield strength, but local buckling is liable to prevent development of the plastic moment resistance . • Class 4 cross-sections are those in which local buckling will occur before the attainment of yield stress in one or more parts of the cross-section.
Moment rotation behaviour of cross-sections of different classes
LOADING • Dead Load • Imposed Load • Wind Load • Snow load • Indirect Forced (eg : soil settlement and structure deformation due to temperature) • Load Combination Direct Forced
THANK YOU VERY MUCH FOR YOUR ATTENTION