The Joplin Globe
The engineers with the American Society of Civil Engineers who came to Joplin and painstakingly surveyed the damage caused by the tornado on May 22, 2011, believe houses in “Tornado Alley’’ should be built to withstand hurricane-force winds.
If the houses in Joplin had been built to that level when the tornado struck, it is likely far fewer of them would have been destroyed — particularly those outside of the narrow path were the EF-5 winds peaked at 200 mph. About the only way you can protect yourself from an EF-4 or an EF-5 is in a fortified shelter.
What this means is that fewer people would have died and fewer would have been injured had our houses been better constructed to withstand wind. The engineers believe we can do better. Houses are being constructed in Florida and other coastal areas that can survive 130 mph winds.
The civil engineers mapped the damage and found that winds equivalent to those produced by EF-0, EF-1 and EF-2 tornadoes — winds of 135 mph or less — caused 83 percent of the damage in Joplin. A Category 3 hurricane has wind speeds of 130 mph.
Had the houses been constructed with simple hurricane clips — metal pieces that bolster the connection between the roof and the exterior wall — fewer of them would have been blown away, exposing the occupants inside.
When city inspectors saw the damage, they immediately recommended that all new home construction in Joplin have hurricane clips. They also tightened the spacing of anchor bolts and took steps to improve the strength of masonry walls. The adoption of those recommendations has put Joplin years ahead of the building code changes that are being proposed by the civil engineers who came to Joplin.
Critics of building codes say you can’t build a house strong enough to withstand a tornado. That’s true of an EF-4 or an EF-5, but you can build them to withstand an EF-2 or less. They account for 90 percent of all tornadoes.
A convincing case for tornado-resilient building codes has been made. Let’s hope the lessons learned in Joplin will save lives when the next tornado hits.