Advantages and Disadvantages of Connections in Steel Structure

ADVANTAGES AND DISADVANTAGES

Advantages It has high strength per unit mass. Its quality is assured speed of construction is high. It

can be strengthened at any other time, if there is need. It can be fabricated in workshop and

transported to site. Material is reusable.

Disadvantages It is susceptible to corrosion. Maintenance cost is high.

Types of Steel

Structural steel – Rolled steel sections are made of such steel. It is also known as Fe-410 or E-250

steel. Fe – 410 – Cu – S means copper bearing steel with ultimate tensile strength of 410 MPa.

Weldable quality steel Fe 540 (E 410), Fe - 570 (E 450) and Fe 590 (E 450) steel are also available.

Properties of Steel

Irrespective of its grade physical properties of steel may be taken as given below:

Unit mass r = 7850 kg/m3

E = 2 × 10

5 N/mm2

m = 0.3

G = 0.769 × 10

5 N/mm2

a = 10 × 10

-6

/°C

Rolled Steel Sections

Rolled steel sections are available in the form of I–sections, channel sections, angle sections, T–

sections, bars, tubes, plates, flats and strips.

Various types of sections and their properties may be seen in steel tables.

Considerations in Steel Design

It involves

1. Selecting suitable size and shape

2. Avoiding buckling

3. Providing minimum thicknesses

4. Detailing and designing connections

Loads

1. Dead loads

2. Imposed loads which include live load, crane load, snow load, dust load, impact loads

horizontal loads on parapets, hydrostatic and earth pressure.

3. Wind loads

4. Earthquake loads

5. Erection loads

6. Accidental loads

7. Secondary effects

IS 875 may be referred to get magnitude of loads

Methods of Design

IS 800–2007 suggests use of limit state design widely and restricts working stress method only

wherever limit state design cannot be applied.