AISC Design Guide 12 – Modification Of Existing Welded Steel Moment Frame Connections For Seismic (KET0032)

Modification Of Existing Welded Steel Moment Frame Connections For Seismic, Contents:

1. Introduction

1.1 Background

1.2 Factors Contributing to Connection Failures

1.3 Repair and Modification

1.4 Objective of Design Guide.

2. Achieving Improved Seismic Performance

2.1 Reduced Beam Section

2.2 Welded Haunch

2.3 Bolted Bracket

3. Experimental Results

3.1 Related Research

3.1.1 Reduced Beam Section

3.1.2 Welded Haunch

3.1.3 Bolted Bracket

3.2 NIST/AISC Experimental Program

3.2.1 Reduced Beam Section

3.2.2 Welded Haunch

3.2.3 Bolted Bracket

4. Design Basis For Connection Modification

4.1 Material Strength

4.2 Critical Plastic Section

4.3 Design Forces

4.3.1 Plastic Moment

4.3.2 Beam Shear

4.3.3 Column-Beam Moment Ratio

4.4 Connection Modification Performance Objectives

4.5 Selection of Modification Method

5. Design of Reduced Beam Section Modification

5.1 Recommended Design Provisions

5.1.1 Minimum Recommended RBS Modifications

5.1.2 Size and Shape of RBS Cut

5.1.3 Flange Weld Modifications

5.1.4 Techniques to Further Enhance Connection Performance

5.2 Additional Design Considerations

5.3 Design Example

6. Design of Welded Haunch Modification

6.1 Recommended Design Procedure

6.1.1 Structural Behavior and Design Considerations

6.1.2 Simplified Haunch Connection Model and Determination of Haunch Flange Force

6.1.3 Haunch Web Shear

6.1.4 Design Procedure

6.2 Recommended Detailing Provisions

6.2.1 Design Weld

6.2.2 Design Stiffeners

6.2.3 Continuity Plates

6.3 Design Example

7. Design of Bolted Bracket Modification

7.1 Minimum Recommended Bracket Design Provisions

7.1.1 Proportioning of Bolted Haunch Bracket

7.1.2 Beam Ultimate Forces

7.1.3 Haunch Bracket Forces at Beam Interface

7.1.4 Haunch Bracket Bolts

7.1.5 Haunch Bracket Stiffener Check

7.1.6 Angle Bracket Design

7.1.7 Requirements for Bolt Hole and Weld Size

7.1.8 Column Panel Zone Check

7.1.9 Column Continuity Plate Check

7.2 Design Example

8. Considerations for Practical Implementation

8.1 Disruption or Relocation of Building Tenants

8.2 Removal and Restoration of Collateral Building Finishes

8.3 Health and Safety of Workers and Tenants

8.4 Other Issues

9. References

Modification Of Existing Welded Steel Moment Frame Connections For Seismic

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