Published on Nov. 16, 2015.
If a Category 3 or higher hurricane hits Honolulu, the city is not prepared, at least in terms of buildings.
According to George Atta, director of the city Department of Planning and Permitting, the existing building code only requires resistance to a wind load of a Category 2 hurricane, which would have sustained winds of 96-110 miles per hour. However, different types of buildings can have different requirements.
“To get hit by a Category 3 storm is going to be hard,” Atta said. “And while you can change the building codes, just the scale of all of the buildings in Honolulu, if we changed the building code to require a Category 3 protection — like some of the Gulf coast cities now have protection to Category 3 — it’ll be very, very expensive, first of all.”
A major storm
Atta was part of a Nov. 12 panel on campus that discussed the lessons learned from Hurricane Katrina and the implications for the state. The panel included University of Hawai‘i at Mānoa Meteorology Professor Gary Barnes, Sociology Lecturer Jennifer Darrah, Engineering Professor Ian Robertson and National Disaster Preparedness Training Center Executive Director Karl Kim, who moderated the panel.
As the third deadliest storm in the U.S., Hurricane Katrina made landfall as a Category 3 storm, flooded 80 percent of the city and caused an estimated $150 billion in damages. Approximately 1,400 people were killed.
According to Barnes, the storm was very well-forecasted, but the human response to it was a big issue.
“The social portion of dealing with disasters or responding correctly to disasters is one of the big issues that I don’t know how to solve,” Robertson said at the panel.
As a structural engineer, he learned three main lessons from the disaster:
•Blind reliance on engineered structures is not always prudent. • Surge and wave action is more damaging than wind.
•Good engineering and advanced
preparation are essential to improving resilience for these mega events.
On O‘ahu, 76 bridges are located in coastal areas, with 27 being labeled in a state Department of Transportation study as “critical.” One of the bridges in trouble is Kahalu‘u Stream Bridge on the east side, which lies only three- to five- feet above sea level. While Kāne‘ohe Bay is secluded because of its reef, this makes no difference to the storm surge, Robertson said.
However, many of the bridges around the island have been rebuilt, such as the one for Punalu‘u Stream.
For buildings, wind is going to cause damage, though Robertson said it can be solved.
“Hurricane clips strap down the side of the house and make a huge difference,” he said. “The houses that get damaged are the old single wall construction with no connection between the roof and the walls and the walls and the foundation. We solved that problem because the codes do require it.”
According to Atta, this requirement is for new residential buildings. His department hopes to bring an updated version of the building code up for adoption next year.
What can really be learned from Katrina is that evacuation is the way to save lives.
“Somehow we have to convince people that they need to get away from the shoreline, and if they’re in substandard homes, they should go to refuge,” Robertson said. “If you’re in a decent 1980 plus home, it may be better to stay at home because there’s not enough storm shelters for everybody.”
There are enough shelters for about one-third of O‘ahu’s population, but according to Atta, only half of them are adequate.
However, he said the city’s emergency response system is better than most states and some communities have even prepared localized responses.