📋 Case Study

Hospital Seismic Upgrade in Christchurch

Preserving historic façade while achieving NZS 1170.5 performance targets (NBS ≥ 65%)

🏗️ Project Overview

Life-safety upgrade of 1970s RC frame hospital following Canterbury earthquakes

🎯 Challenge

Preserving historic façade while achieving NZS 1170.5 performance targets (NBS ≥ 65%)

🔧 Design Approach

RC jacketing with confined concrete cores, energy-dissipating links, and displacement-based design per ASCE 41-17

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Jacket Confinement Pressure

f_l = 4.1×A_s,h×f_yh/(s×d_c)

Result: 4.3 MPa

Triggers 2.5× compressive strength gain in core concrete

Link Rotation Demand

θ_u ≥ 0.02 rad

Result: 0.024 rad

Guarantees plastic hinge formation outside structural walls

📊 Results

NBS increased from 32% to 71%; full occupancy maintained during phased construction

💡 Lessons Learned

• •Existing rebar splice locations dictate jacket continuity
• •Non-destructive bond testing (pull-out) is mandatory before grouting

✅ Key Takeaways

• 1Existing rebar splice locations dictate jacket continuity
• 2Non-destructive bond testing (pull-out) is mandatory before grouting