ToolFusion Civil
ToolFusion Civil
📋 Case Study

Northeast Bridge Replacement – Field-Welded Flare-Bevel Moment Connections

Field welding in marine environment with high humidity and salt exposure requiring corrosion-resistant detailing

🏗️ Project Overview

Replacement of 1950s steel truss bridge with modern orthotropic deck system

🎯 Challenge

Field welding in marine environment with high humidity and salt exposure requiring corrosion-resistant detailing

🔧 Design Approach

Flare-bevel groove welds with E110K2 electrodes, post-weld heat treatment (PWHT), and duplex stainless steel backing strips; all welds inspected via phased-array UT

📐 Design Diagram

Northeast Bridge Replacement Field-Welded Flare-Bevel Moment Connections Pier A Pier B Steel Girder (W36×150) Flare-Bevel Groove Duplex SS Backing E110K2 Weld Tp = 215°F PWHT 2.5 hr hold Phased-Array UT Marine Env.: High Humidity & Salt Exposure → Corrosion Risk Structure Weld Detail Corrosion Mitigation Environmental Challenge

AI-generated project design illustration

📐 Key Calculations

Minimum Preheat Temperature

Tp = 150°F + 0.5×(C_eq − 0.4)×100
Result: 215°F
Prevents hydrogen-induced cracking

PWHT Holding Time

1 hr per inch of thickness
Result: 2.5 hrs
Ensures stress relief in 2.5-in plate

📊 Results

Zero weld defects found during final inspection; 100% UT pass rate across 42 connections

💡 Lessons Learned

  • •PWHT scheduling must coordinate with tidal windows
  • •Duplex backing strips eliminate root corrosion but require special grinding procedures

✅ Key Takeaways

  • 1PWHT scheduling must coordinate with tidal windows
  • 2Duplex backing strips eliminate root corrosion but require special grinding procedures