impImportant Question And Problems With Answer: Connections - Riveted, Welded & Bolted

Important Question and Problems With Answer: CONNECTIONS - RIVETED, WELDED & BOLTED

1.     Mention the advantages and disadvantages of steel structures? Advantages:

Ability to resist high loads

Due to its high density, steel is completely non-porous Durability

Easy to disassembling or replacing some steel members of a structure Disadvantages:

Corrosion

At high temperature steel loses most of its strength, leading to deformation or failure

2.     What is meant by Girder?

Girder means a major beam frequently at wide spacing that supports small beams.

3. What is meant by joists?

It is a closely spaced beam supporting the floors and roofs of  buildings

4. What is meant by Purlins?

It is a roof beam usually supported by trusses

5. What is meant by Rafters?

It is a roof beam usually supported by purlins

6. What is meant by Lintel?

It is a beam over window or door openings that support the wall above.

7. What is Girts?

It is horizontal wall beams used to support wall covering on the side of an industrial building 8. What is meant by Spandrel beam?

It is beam around the outside perimeter of a floor that support the exterior walls and the outside edge of the floor

9.     Name the different types of connections? Riveted connections

Welded connections Bolted connections

Pinned connections

10.Name the types of riveted connections?

Lap Joint - single riveted and double riveted Butt joint - single cover and double cover

11.What is meant by rivet value?

The least of the strengths in shearing and bearing is the rivet value

12. What is meant by gauge distance?

The perpendicular distance between two gauge lines, is called gauge distance

13.Name the different modes of failure of a riveted joint? Tearing failure of the plate

Shear failure of the plate Shear failure of the rivet Bearing failure of the rivet Splitting failure of plate

14.As per the American practice where the neutral axis lie in the rivet group?

It is assumed that the line of rotation lies at a distance of 1/7 th of the effective bracket depth from the bottom of the bracket

15.What are the factors that govern will govern the structural design? Foundation movements

Elastic axial shortening Soil and fluid pressures Vibration

Fatigue

Impact (dynamic effects) Erection loads

16.What are the load combinations for the design purposes? Dead load + Imposed Load (Live load)

Dead Load + Imposed Load + Wind Load or earthquake load Dead Load + Wind Load or Earthquake load

17.What are the steps involved in structural design? Forces or loads

Structural arrangement and material selection

        Analyzing internal stresses     

        Proportioning of members     

18.   Which type of steel is most commonly used in general construction? Why?

        Mild Steel is most commonly used in general construction because of its

durability and malleability    

19.   What are Black bots? Where are they used?       

Black bolts made from M.S shank left unfinished - remain loose in holes resulting in large

deflections. It is used during erection and for temporary structures

20.   How the rolled steel beams are classified? Indian Standard junior beams (ISLB) Indian Standard light beams (ISLB)

Indian Standard medium weight beams (ISMB) Indian Standard wide flange beams (ISWB)

21.   Define permissible stresses and Working stresses.

Permissible stresses      =       yield stress 

factor of safety

Working stresses: The stresses used in practical design are working stresses and they should never exceed the permissible stresses specified by codes.

22. Explain ISLB 200?

ISLB 200 means Indian Standard light gauge beams of depth 200mm 23. Name the types of beam connections?

Framed connections

Seated connections - Stiffened connections and Unstiffened connections 24. What is meant by framed connections?

A framed connection is the one when a beam is connected to girder or a stanchion by means of two angles placed on the two sides of the web of the beam

25. When the seated beam connections are preferred and name the types?

When a beam is connected to the flange (or the web) of a steel stanchion, the width of the flange (or the depth of the web) may be insufficient to accommodate the connecting angles, in such cases framed connection is not suitable and seated connection is preferred.

26. What is unstiffened seat connection?

The seated connection is a horizontal angle with its horizontal leg at its top is used to

 receive the beam on it, in such a case it is called unstiffened seat connection

27. What is stiffened seat connection?

In addition to the seat angle, a web cleat is provided when the beam is connected to a

beam and  a flange        cleat  is       used  when  the  beam  is  connected  to  a  stanchion.  The  angle

cleats  are essential       because       they keep the beam stable in a vertical position and prevent it

from lateral buckling   

28. What is meant by throat thickness?

It is the perpendicular distance from the root to the hypotenuse of the largest

isosceles right-angled triangle that can be inscribed within the weld cross-section.

Throat thickness = 0.7 x size of the weld 29. What is plug weld and slot weld?

Slot weld is one of the type of weld used to join the two touching contiguous

components by a fillet weld round the periphery of a slot in one component so as to join it the surface of other component.

Plug weld is made by filling in a hole in one part with filler metal so as to join it to

the contiguous part exposed through a hole.

30. Mention the advantages and disadvantages of welded connections?

Advantages:

Economy

Rigidity

Aesthetic effect

Versatility

Disadvantages:

Requires skilled labour

Joints are over rigid

Difficult to inspect

31. State the common defects in

welding

Incomplete fusion

Incomplete penetration

Porosity

Slag inclusions

Cracks

Under cutting

32. Name the types of bolted connections?

Ordinary unfinished 0r black bolts

Turned and fitted bolts

High strength bolts

33.Write the advantages of high strength bolts?

As there is no slip between the plates, the joint is rigid

Alternating loads cause little variation of the stresses in the bolts; hence fatigue strength is

also high.

No shearing or bearing stresses occur in bolts.

High strength of the joint due to high frictional resistance is obtained.