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Unit – 2

Connections

Q1) What is connections?

A1)

In engineering, a connection serving to sign up for the man or woman participants of a shape, to make certain the reliability of the shape, and to offer for the right functioning of the shape as an entire in accord with the necessities of use and assembly.

The metallic systems are built through well connecting the to be had fashionable sections. The connections are a vital a part of metallic shape and are designed greater conventionally than any man or woman participants.

There is a discrepancy among the real conduct and the evaluation of metallic shape is large, consequently the connections are complicated to research and layout.

When the structural member fails in case of overloading then there may be a fashionable exercise to pick the man or woman member as opposed to the connections, consequently this form of exercise influences many structural participants.

Q2) When we need use of connections?

A2)

When there may be the requirement to cater the heavy load and lengthy span then the built-up sections are to be supplied. In this situation, this segment ought to be linked collectively to get an amazing segment.

In case of longer span, the period of fashionable segment desires to be linked with different segment. In this situation to attach a couple of sections right layout of connections are vital.

The unique participants want to be linked on the quit (as an instance secondary beams to be linked to number one beam, column, footings, etc.).

Q3) What are the types of connections?

A3)

Riveted connections

Bolted connections

Welded connections

Pinned connections

Q4) Explain types of rivets.

A4)

Hot pushed rivets: The rivets which might be pushed withinside the warm conditions

Shop rivets: The rivets which might be located in workshop

Field rivets: The rivets which might be located withinside the site/field.

Cold pushed rivets: Since excessive strain is needed to shape the top at room temperature this kind of rivet is limited.

Q5) Give disadvantage of riveted connections.

A5)

It is related to very excessive stage of noise pollution

There is a want to warmth the rivet until purple warm color.

Skilled labors are vital to investigate the relationship.

The fee to get rid of the poorly hooked up rivet could be very excessive.

Q6) What is bolted connection? Explain.

A6) Most generally used connections consist of the bolted connections. This connection has the benefit of pliability in assembling elements of the shape as well as dissembling it and that is vital if there may be inspection or a few routine maintenances. This kind of connections is relevant for participants subjected to anxiety or shear or each anxiety and shear.

The blessings of bolted connections are as follows:

The technique of erection of shape may be made faster.

Skilled labors aren't vital.

Connections do now no longer contain the noise.

Requirement of labors is less.

Q7) Write a note on classification of bolted connection.

A7)

Concentric connections: When the burden of structural member passes via the CG of the segment then this kind of connections are made.

Eccentric connections: Whenever the ensuing pressure is performing far from the CG of the connections.

Moment resisting connections: Whenever the connections are subjected to moments.

Q8) Write a short note on layout of philosophy.

A8)

The traditional technique to research the relationship is primarily based totally at the following conditions:

The deformation of the relationship is omitted because the linked factors of the systems is taken into consideration as inflexible connections

The connectors used to attach unique factors of the segment behave like linear – elastic manner till it fails.

The ductility belongings of connectors of the systems are unlimited.

Q9) Write a short note on structural fasteners.

A9)

Structural fasteners are strong, heavy-duty fasteners that are vital for the development of structures which consist of metallic-to-metallic connections.

To be taken into consideration for structural purposes, fasteners want to be fabricated from quenched and tempered metallic with a minimum tensile electricity of one hundred twenty ksi.

Structural fasteners are strong, heavy-duty fasteners that are vital for the construction of structures which consist of metallic-to-metallic connections.

In other words, they're used whilst one metal structure needs to be related to another.

The regular application of structural fasteners is in bridge and building construction, where they're used to connect metal beams and girders.

Q10) Explain Rivet.

A10)

A rivet is a mechanical fastener for creating an everlasting be a part of among or more metal sheets. Riveting is the act of fastening or securing plates with one or more rivets.

The rivet accommodates a shank with an undeniable stop (or tail), and a head on the opposite stop.

The rivet has proved to be one of the maximum reliable and safe way of fastening, forming an everlasting and structurally sturdy be a part of.

The method of riveting (or creating a riveted joint) accommodates making an entire in say, metal plates, aligning the hole, then putting the rivet thru it with the undeniable stop projecting thru (‘A’ withinside the diagram).

Q11) Explain types of bolts.

A11) Anchor bolt

Usually embedded in concrete or masonry for structural applications.

Carriage bolt

Used to fasten steel to timber, with a squared undercut to the head which holds the bolt in place as soon as it has been tightened.

Elevator bolt

Commonly utilized in conveyor systems, an elevator bolt has a flat, undeniable or countersunk head which holds the bolt in place whilst tightened.

Flange bolt

Also referred to as frame bolts, this form of bolt distributes the bearing load the use of a washer at the undercut of the head.

Hanger bolt

This form of bolt contains threaded ends rather of getting a head, one in every of which contains a wood screw.

Hexagon bolt/Tap bolt

A hexagon bolt contains a head that has six sides, with threading that starts off evolved part-manner down the shank, while a tap bolt’s shank is threaded the complete length.

Q12) What are the different kinds of bolt heads.

A12)

Square shoulder: A truss head, shaped if you want to allow fastening with the least quantity of floor obstruction, on a rectangular shank which resists rotation.

Indented hexagon: For use with a wrench, this head has a round despair in its pinnacle floor.

Indented hexagon washer: Same as an indented hexagon, however with the addition of a washer section at the bottom to shield the assembly finish from the wrench.

Q13) Write note on Welds.

A13)

Welding is a fabrication system wherein or extra elements are fused collectively by way of heat, pressure or each forming a be a part of because the elements cool.

Welding is generally used on metals and thermoplastics however also can be used on wood. The finished welded joint can be called a weldment.

Some substances require the use of unique approaches and techniques.

A quantity is considered unweldable, a time period now no longer generally determined in dictionaries however beneficial and descriptive in engineering.

Q14) What are the types of welding joint?

A14) Gas Metal Arc Welding (GMAW/MIG)

This fashion of welding is likewise referred to as Metal Inert Gas (MIG). It makes use of a defensive fueloline alongside the twine electrode, which heats up the 2 metals to be joined. This technique calls for a constant voltage and direct-contemporary electricity source, and is the maximum not unusual place industrial welding system. It has 4 number one strategies of steel transfer: globular, brief-circuiting, spray and pulsed-spray.

Gas Tungsten Arc Gas Welding (GTAW/TIG)

Welding collectively thick sections of chrome steel or non-ferrous metals is the maximum not unusual place use for this technique. It is likewise an arc-welding system that makes use of a tungsten electrode to supply the weld. This system is plenty extra time eating than the opposite 3 and plenty extra complex.

Shielded Metal Arc Welding (SMAW)

With this precise form of welding, the welder follows a guide system of stick welding. The stick makes use of an electric contemporary to shape an arc among the stick and the metals to be joined. This is frequently used withinside the production of metallic systems and in industrial fabrication to weld iron and metallic.

Flux Cored Arc Welding (FCAW)

This becomes evolved as an opportunity to defend welding. The semi-computerized arc weld is frequently utilized in production projects, way to its excessive welding velocity and portability.

Q15) Explain bolted shear connections.

A15)

• We need to layout the bolted shear connections in order that the factored layout power (φ Rn) is extra than or identical to the factored load.

• So, we want to look at the diverse viable failure modes and calculate the corresponding layout strengths.

• Possible failure modes are:

- Shear failure of the bolts

- Failure of member being linked because of fracture or block shear or ….

- Edge tearing or fracture of the linked plate

- Tearing or fracture of the linked plate among bolt holes

- Excessive bearing deformation on the bolt hole

Q16) What are the commonly use welded and bolted connection?

A16)

Beam-to-beam and beam-to-column connections using:

Partial intensity quit plates

Full intensity quit plates

Fin plates

Column splices (bolted cowl plates or quit plates)

Column bases

Bracing connections (Gusset plates).

Q17) Write short note on Eccentric Connections?

A17) If the force applied does not passes through the CG of the joint then such joint carries moment in addition to an axial direct force. Such types of connections are called as eccentric connections.

Two common loading conditions are discussed in the next two sections, followed by a discussion of the generalized approach for distributing applied loads over a bolt pattern.

In-Plane Eccentric Shear Load. ...

Out-of-Plane Eccentric Shear Load. ...

Generalized Approach. ...

Bolt Pattern Moments of Inertia. ...

Axial Forces. ...

Shear Forces.

Q18) What are the connections subjected to eccenrtic shear?

A18) Seat Connections

Framed Connections

Bracket Connections

Q19) Explain deesginn method of bolted connection.

A19) The full design method for an endplate connection is necessarily an iterative procedure: a configuration of bolts and, if necessary, stiffeners are selected; the resistance of that configuration is evaluated; the configuration is then modified for greater resistance or greater economy, as appropriate; the revised configuration is re-evaluated, until a satisfactory solution is achieved.

STEP 1

Calculate the effective tension resistances of the bolt rows. This involves calculating the resistance of the bolts, the end plate, the column flange, the beam web and the column web. The effective resistance for any row may be that for the row in isolation, or as part of a group of rows, or may be limited by a 'triangular' distribution from compression flange level.

The conclusion of this stage is a set of tension resistances, one value for each bolt row, and the summation of all bolt rows to give the total resistance of the tension zone.

STEP 2

Calculate the resistances of the compression zone of the column web, taking account of the shear force in the column web, and of the beam flange.

STEP 3

Calculate the shear resistance of the column web.

STEP 4

If the total tension resistance exceeds the compression resistance, (Step 2) or column web shear resistance (Step 3), calculate reduced effective tension resistances for the bolt rows, where necessary to ensure equilibrium.

Calculate the moment resistance. This is the summation of the products of bolt row force multiplied by its respective lever arm, calculated from the center of compression.

STEP 5

Calculate the shear resistance of the bolt rows. The resistance is taken as the sum of the full shear resistance of the bottom row (or rows) of bolts (which are not assumed to resist tension) and 28% of the shear resistance of the bolts in the tension zone (assuming, conservatively, that they are fully utilized in tension).

STEP 6

Verify the adequacy of any stiffeners in the configuration.

STEP 7

Verify the adequacy of the welds in the connection. (Note that welds sizes are not critical in the preceding Steps).

Components in compression in direct bearing need only a nominal weld, unless moment reversal must be considered.

Q20) Write note on bolted and welded connection.

A20)

Welded joints are extra rigid than bolted joints, due to the continuity of the pass section.

On the opposite hand, bolted joints are related with plates or angles, and the deflection of those factors throughout load switch provides flexibility.

For this reason, bolted joints permit extra motion with much less structural stress.

These are nominally pinned connections that are assumed to transmit quit shear best and to have negligible resistance to rotation. Therefore, do now no longer switch big moments on the closing limit state.

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