23.1.2 - Types of Bolted Connections
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Introduction to Bolted Connections
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Today, we're going to learn about bolted connections, which are critical in steel structures. Can anyone tell me what a bolted connection is?
Is it when we use bolts to connect different parts of a structure?
Exactly! Bolted connections involve the use of bolts to fasten structural elements together. They're favored over rivets and even welding for certain applications. Why do you think that is?
Maybe because they’re easier to install?
That’s one reason. They're also less labor-intensive and can avoid issues like secondary cracking that can occur with welds. Now, can anyone think of the two types of bolted connections we'll discuss today?
Are they bearing-type and slip-critical connections?
Correct! Let’s dive deeper into each of those types.
Bearing-Type Connections
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First up is the bearing-type connection. How do you think this type transmits load?
Is it through shear forces and direct contact with the bolt?
Yes! Bearing-type connections transmit loads through shear and bearing on the bolt. It’s crucial that the bolts are adequately sized. Can anyone remember the typical failure modes associated with these connections?
I think it could be related to the bolts failing under high shear loads?
Great insight! These connections must be designed to prevent such failures during service loads.
Slip-Critical Connections
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Now, let's talk about slip-critical connections. Why are they called 'slip-critical'?
Because they rely on friction to hold the load, right?
Exactly! They depend on tension in the bolts to create friction and prevent slippage. Why do you think it’s important that these connections don’t slip under service loads?
If they slip, the structure could become unstable!
Right! It can lead to significant load redistribution and potential failure. That's why proper design and installation are key.
Comparison of Connection Types
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Can anyone summarize the key differences between bearing-type and slip-critical connections?
Sure! Bearing-type relies on shear and bearing, while slip-critical relies on friction.
Awesome! And when would each type be preferable?
Bearing-type for simpler applications where slip isn't a huge concern, and slip-critical when you need extra stability.
Exactly! Each connection type has its unique situations where it’s most effective. Great job today everyone!
Introduction & Overview
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Quick Overview
Standard
Bolted connections are classified into two main types: bearing-type connections, which transmit loads through shear and bearing on the bolt, and slip-critical connections, which rely on friction to transmit loads without slipping. Understanding these types is crucial for the design and integrity of structural connections.
Detailed
Types of Bolted Connections
In structural engineering, bolted connections are vital for ensuring the stability and load-bearing capacity of various constructions. There are two fundamental types of bolted connections:
- Bearing-Type Connections: These connections transfer loads through a combination of shear forces and bearing on the bolt itself. This means that the connection relies on the physical contact between the bolt and the connected plates or angles to handle loads.
- Slip-Critical Connections: These connections, on the other hand, depend on friction to transmit loads. Here, adequate tension in the bolts is necessary to maintain frictional resistance, thereby preventing slip during service loads. It's crucial that these connections can withstand ultimate loads without slipping during operation.
Understanding these different types of connections is significant because each type has its unique design considerations and applications in engineering. Additionally, recognizing the potential failure modes associated with each type is fundamental for safe and effective design.
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Types of Bolted Connections Overview
Chapter 1 of 2
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Chapter Content
There are two types of bolted connections:
6 Bearing type which transmits the load by a combination of shear and bearing on the bolt, Fig. 23.2.
Slip-critical transmits load by friction, Fig. 23.3. In addition of providing adequate at ultimate load, it must not slip during service loads.
Detailed Explanation
In this section, there are two main types of bolted connections: Bearing type and Slip-critical.
- Bearing Type: This type of connection works by transferring the load through a mix of shear forces and bearing against the bolt. Essentially, when weight is applied, the load pushes against the bolt, which helps in holding the connection securely.
- Slip-Critical Type: This connection relies on friction to transmit loads. It means that the surfaces that are bolted together must be pressed tightly enough so that they won't slip apart, even when the load is applied. This type of connection also needs to ensure that it can handle maximum loads without slipping during regular use.
Examples & Analogies
Think of the Bearing type connection like a clamp holding a piece of wood; when you apply weight to it, the clamp keeps the wood from moving. Conversely, the Slip-critical connection is like two hands gripping a large box tightly; if you hold it firm enough, it won’t slip out of your grasp even while moving it around.
Failure Modes of Bolted Connections
Chapter 2 of 2
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Chapter Content
Possible failure modes (or limit states) which may control the strength of a bolted connection are shown in Fig. 23.4.
Detailed Explanation
In every bolted connection, different failure modes can occur that may impact its strength. These modes are cases where the connection could fail under load. Understanding these limits ensures that engineers can design connections that are safe and reliable.
Examples & Analogies
Imagine a bridge made of several bolted connections. If one of those connections fails under stress, it’s like a link in a chain breaking; the entire structure becomes weaker. Engineers analyze these potential failure modes beforehand to prevent such scenarios.
Key Concepts
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Bearing-Type Connection: This connection type uses shear and bearing to transmit loads.
-
Slip-Critical Connection: This connection relies on friction, necessitating adequate tension to avoid slipping.
Examples & Applications
A bridge connection using slip-critical bolted connections to prevent movement during high winds.
A steel framework utilizing bearing-type connections to connect beams and columns.
Memory Aids
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Rhymes
When bolts bear the load, they shear and press, slip-critical bolts, keep tension to impress.
Stories
Once there were two friends, Bear and Slip. Bear loved to push his weight on the ground, while Slip always made sure to hold tightly onto the surface he was on. Together, they built strong bridges, one using pressure and the other using friction.
Memory Tools
Remember 'B' for Bearing-type (Bears push down) and 'S' for Slip-critical (Slipping surfaces must hold tight).!
Acronyms
B-S
for Bearing
for Slip - Recall the types of bolted connections!
Flash Cards
Glossary
- BearingType Connection
A type of bolted connection that transmits loads through shear and bearing on the bolt.
- SlipCritical Connection
A bolted connection where the load is transmitted through friction, requiring adequate tension in the bolts.
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