Structural Engineering: Bolted Connections

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Questions and Answers

What is a potential drawback of bolted connections in architectural features?

Less susceptibility to corrosion

Reduced aesthetic appeal (correct)

Lower maintenance requirements

Increased strength

What type of forces are critical in connections subjected to pulling or stretching forces?

Tension forces (correct)

Frictional forces

Moment forces

Shear forces

Why are moment-resistant connections essential?

To reduce the risk of corrosion

To maintain structural integrity under complex loading conditions (correct)

To increase the connection's flexibility

To allow end rotations of unrestrained beams

What is the primary reason for regular inspection and maintenance of bolted joints?

All of the above Signup and view all the answers

What type of connections are designed to allow end rotations of unrestrained beams?

Simple connections Signup and view all the answers

What is the primary mechanism of shear resistance in bearing-type connections?

Bolt shaft bearing against metal plates Signup and view all the answers

What is a critical consideration in designing bolted connections?

Both tension and shear forces need to be considered Signup and view all the answers

Why do slip-critical connections require proper tightening of bolts?

To achieve the required frictional resistance Signup and view all the answers

What is a primary advantage of bolted connections?

They can withstand significant loads and stresses. Signup and view all the answers

What is a potential disadvantage of bolted connections in corrosive environments?

They may require additional protective measures. Signup and view all the answers

Why may bolted connections not be suitable for certain applications?

They are limited by the size and type of bolts available. Signup and view all the answers

What is the type of failure that occurs when the bolt fails due to shear forces?

Single Shear Failure Signup and view all the answers

What can occur if bolted connections are not properly maintained under dynamic or cyclic loading?

They may loosen over time. Signup and view all the answers

What is a limitation of bolted connections in terms of load distribution?

They may not distribute loads as evenly as welded joints. Signup and view all the answers

What is the minimum yield strength of A36 steel?

36,000 psi Signup and view all the answers

What is the design consideration that affects the available bearing strength at bolt holes?

Deformation at service load Signup and view all the answers

What is a potential consequence of incorrect installation of bolted connections?

They may lead to issues such as loosening of bolts under vibration. Signup and view all the answers

Why are bolted connections widely used in structural applications?

They are very easy to operate and no special equipment is required. Signup and view all the answers

What type of failure occurs when the bolt fails due to tension forces?

Tension Failure Signup and view all the answers

What is the formula to determine the available bearing strength at bolt holes?

Fu / Lc Signup and view all the answers

What is a benefit of bolted connections in terms of environmental conditions?

They can be installed in a wider range of environmental conditions. Signup and view all the answers

What is the type of failure that occurs when the bolt fails due to bearing forces?

Bearing Failure Signup and view all the answers

What is the purpose of excluding threads from the shear plane?

To increase the shear strength Signup and view all the answers

What is the type of connection shown in the sample problem?

Bearing type connection Signup and view all the answers

Study Notes

Aesthetic Considerations

Bolted connections can be less aesthetically pleasing compared to seamless welded joints.
This is a concern in exposed architectural features.

Potential for Corrosion

Bolted joints can be more susceptible to corrosion.
This is particularly true in outdoor or harsh environments.
Additional maintenance and protection are required.

Bolt Failure

Bolts can fail due to over-tightening, fatigue, or environmental degradation.
Regular inspection and maintenance are necessary.

Forces in Bolted Connections

Tension forces pull the bolt along its length.
Critical in connections subjected to pulling or stretching forces.
Shear forces act perpendicular to the bolt's axis, causing the bolt to shear off.
Important in connections where parts are sliding against each other.

Considerations in Bolt Design

Both tension and shear forces need to be considered.
This ensures the connection's strength and stability.

Simple vs. Moment-Resistant Connections

Simple connections (flexible beam connections) allow end rotations of unrestrained beams.
Some inelastic deformation is permitted to accommodate movement.
Moment-resistant connections resist forces from both moment and shear.
Essential for maintaining structural integrity under complex loading conditions.

Bearing and Slip-Critical Connections

Bearing-type connections rely on the bolt shaft bearing against the metal plates.
Bolts do not need to be tightened to a specific tension.
Slip-critical connections rely on friction between the connected surfaces.
Bolts need to be properly tightened to achieve the required frictional resistance.

Advantages of Bolt Connections

Easy to install with less specialized equipment and minimal training.
Can be easily disassembled for future modifications, repairs, or expansions.
Can be installed in a wider range of environmental conditions.
Properly designed bolted connections can withstand significant loads and stresses.
Suitable for a wide range of structural applications and materials.

Disadvantages of Bolt Connections

May not distribute loads as evenly as welded joints, potentially leading to stress concentrations.
Load distribution can be uneven.

Modes of Failure in Bolt Connections

Failure of the bolt can occur due to single shear, double shear, bearing, or tension failure.
Failure of the bolt can occur due to various modes.

Area of Bolt and Tensile Strength of Plate

Area of bolt and tensile strength of plate are important considerations in bolt design.

Bearing Strength at Bolt Holes

Bearing strength at bolt holes is determined for the limit state of bearing.
Deformation at the bolt hole at service load can be a design consideration.
The available bearing strength at bolt holes can be determined using Fu and Lc.

Sample Problem

The available strength of a bearing type connection can be determined using A36 steel and A325 bolts.

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Description

This quiz covers the limitations and potential issues of bolted connections in structural engineering, including aesthetic concerns, corrosion, and bolt failure.