Protecting infrastructure from hurricanes: Lessons learned about the importance and effectiveness of adopting and following modern building codes Tim Reinhold Institute for Business & Home Safety
Design Standards for Manufactured Housing Pre – No standards, lots of singlewides – Generally very poor performance – HUD Code, more doublewides – Two design levels – not tied to modern wind std. – Better performance but lots of damage Post 1994 – Wind zones 1-3 – ASCE 7-88 loads and wind map – Clearly superior performance
Strengthening Codes Works
Attached Structures
New Commercial Structure in Punta Gorda
Older Commercial Structure across street in Punta Gorda
Windborne Debris Primary Sources: Roofing Materials Siding Materials Vegetative Debris Structural Components Unsecured Items (Patio Furniture, Potted Plants, lawn ornaments, etc.)
Elimination of Gravel Ballast
Debris and Internal Pressures
Punta Gorda City Hall & Annex Mitigation Success – Annex in use – City Hall gutted
Aggregate Losses for Charlotte County and Punta Gorda All Building Permits: $1.8 Billion Residential Garage Doors: $2.6 Million Shingle Roofs: $114 Million Tile Roofs: $87 Million Residential Cages: $16 Million
Roof covering and soffit failures lead to interior damage
Roof Covering Failures - Tile Tile Roof Damage Tile insufficiently attached to roof deck:
Continuing Problems: Garage Door Failures Failed primarily due to lack of reinforcement and track bracing for design pressures Some were also damaged by windborne debris
Continuing Problems: Double Entry Doors
Continuing Problems: Gable Ends Gable End Failures – Sheathing loss – Un-braced gables
Reducing Hurricane Risks & Losses
Conclusions Buildings built under the latest codes where enforcement was good – generally performed well structurally (some exceptions) Keys are: – Good up to date code – Uniform and thorough enforcement – Builders and subs who understand and appreciate the risks – Special inspections for key functions
Benefit-Cost Studies for Building Codes Texas A&M Study for TDI Code – For individual provisions large variability – For system of provisions B-C ~ 4 to 7 Seismic Code Study for Utah and LA – B-C of 4.3 for Utah – B-C of 6 to 16 for LA
Recommendations Appropriate funds for National Windstorm Loss Reduction Program authorized last year Increase support for NOAA / FEMA in wind field modeling Increase support for NOAA in hardening and backing up ASOS stations Add incentives for code adoption and enforcement Add incentives for mitigation