ToolFusion Civil
ToolFusion Civil
📋 Case Study

Midwest Warehouse Expansion – Bolted Shear Connections Under Fatigue Loading

Fatigue cracking observed in existing shear tabs after 8 years of service; new expansion required fatigue-resistant detailing

🏗️ Project Overview

150,000 sq ft distribution center with crane runway girders

🎯 Challenge

Fatigue cracking observed in existing shear tabs after 8 years of service; new expansion required fatigue-resistant detailing

🔧 Design Approach

Transition from A325 bolts to A490 bolts with oversized holes eliminated; use of slip-critical connections with SSPC SP10 blast cleaning and Class A faying surfaces

📐 Design Diagram

Midwest Warehouse Expansion – Bolted Shear Connections Under Fatigue Loading Fatigue cracking in shear tabs after 8 yrs A490 bolts • No oversized holes Slip-critical • SSPC SP10 + Class A ΔF_th = 24 ksi (Category C) U = 1.0 Class C Detail No reduction in fatigue life Class A 3" ΔF_th = 24 ksi

AI-generated project design illustration

📐 Key Calculations

Fatigue Stress Range ΔF_th

ΔF_th = 24 ksi (Category C)
Result: 24 ksi
AISC Appendix K allowable stress range

Detail Category Adjustment Factor

U = 1.0 (Class C detail)
Result: 1.0
No reduction applied due to improved surface prep

📊 Results

Predicted life > 20 million cycles at design load; zero field cracks reported after 3 years of operation

💡 Lessons Learned

  • •Surface preparation dominates fatigue performance more than bolt grade
  • •Slip-critical connections require rigorous QA/QC documentation

✅ Key Takeaways

  • 1Surface preparation dominates fatigue performance more than bolt grade
  • 2Slip-critical connections require rigorous QA/QC documentation