Steel structures are made from organised combination of structural STEEL members designed to carry loads and provide adequate rigidity. They involve sub-structures or members in a building made from structural steel. Structural members are physically distinguishable part of structure with independent structural function, e.g. member elements, cable, beams, sections etc
ADVANTAGES OF USING STEEL IN STRUCTURES
- High strength
- 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 erection
The specific strength is a material's strength (force per unit area at failure) divided by its density. It is also known as the strength-to-weight ratio or strength/weight ratio.
Steel structures facilitate ease of fabrication and faster erection of structures. Bolts and welding employed for joining .
DISADVANTAGES OF USING STEEL IN A STRUCTURE
• Susceptibility to corrosion
• Maintenance costs / thin-walled structure
• Loss of strength at elevated temperature
• Fireproofing costs
• Susceptibility to buckling
• Fatigue and brittle fracture buckling phenomenon
Where & when use steel structures?
1) Long-span structures
2)Multi-storey & high-rise buildings
3) Buildings of heavy duty plants
4)Tower & mast structures
5)Portal frames
6)Bridges
7)Infrastructures
8)Deployable structures
9)Generalized structures: mechanical
General Notes:
1) Rivets are a permanent mechanical fastener. Before being installed a rivet consists of a smooth cylindrical shaft with a head on one end.
2) A panel joint is a point of connection between two or more members of a truss. Also called node.
3) A girder is a support beam used in construction. Girders often have an I-beam cross section for strength.
4) A Pin and Hanger assembly is used to connect two plate girders of bridges. These assemblies are used when the space between two bridge piers is too wide to be spanned by a single set of girders
5) Strings are projections used for supporting the deck of a bridge
6) A bridge deck or road bed is the roadway, or the pedestrian walkway, surface of a bridge. It is not to be confused with any deck of a ship.
7) An expansion joint or movement joint is an assembly designed to safely absorb the heat-induced expansion and contraction of construction materials, to absorb vibration, to hold parts together, or to allow movement due to ground settlement or earthquakes.
8) Movement occurs for many different reasons, including variations in climate or temperature, movement in the frame and movement in the foundations. Articulation joints are tied at specific intervals and sealed with filler.
9) Mild steel, also called plain-carbon steel, is the most common form of steel because its price is relatively low while it provides material properties that are acceptable for many applications, more so than iron. Low-carbon steel contains approximately 0.05–0.3% carbon
10) An I-beam, also known as H-beam is a beam with an I- or H-shaped cross- section. The horizontal elements of the “I" are flanges, while the vertical element is termed the "web". The web resists shear forces, while the flanges resist most of the bending moment experienced by the beam. Beam theory shows that the I-shaped section is a very efficient form for carrying both bending and shear loads in the plane of the web 8 9
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