📋 Case Study

Texas Refinery Pipe Rack – Composite Beam-to-Column Shear Connections

Thermal expansion differentials between concrete-filled tubular columns and steel beams causing high secondary moments in connections

🏗️ Project Overview

Heavy-duty pipe rack supporting 36-inch process lines with thermal cycling

🎯 Challenge

Thermal expansion differentials between concrete-filled tubular columns and steel beams causing high secondary moments in connections

🔧 Design Approach

Use of flexible shear connectors (headed studs + elastomeric pads) combined with rotational restraints modeled in STAAD.Pro using connection stiffness matrices

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Thermal Rotation Demand

θ = α·ΔT·L / h

Result: 0.008 rad

Drives required connection rotational capacity

Stud Shear Transfer Efficiency

Q_n = 0.5 × Q_s (with pad)

Result: 62 kips/stud

Reduces stud count by 35%

📊 Results

Measured rack deflections within 0.02 in tolerance over 2-year monitoring; no stud pullout or pad extrusion

💡 Lessons Learned

• •Composite action assumptions must be validated via strain gage instrumentation
• •Connection stiffness input directly affects global frame stability

✅ Key Takeaways

• 1Composite action assumptions must be validated via strain gage instrumentation
• 2Connection stiffness input directly affects global frame stability