Post-Tornado Survey, Moore, OK
On May 20, 2013, nearly two years to the day after Joplin, MO was hit by the EF-5 tornado, Moore, OK is impacted by another powerful tornado resulting in substantial damage to houses, schools, and several fatalities. The National Weather Service classified the Moore tornado as an EF-5 and parts of the damage path were mapped at nearly 2 miles wide. Statistically, such powerful tornadoes have very low probability of occurrences, but by cruel twist of fate, Moore, OK has seen three powerful and destructive tornadoes since 1999 in nearly the same locations, with similar heart-wrenching results. From this tragedy, a unique opportunity has presented itself for us to learn from our past rebuilding efforts, to understand whether our structures have improved over time, and to improve knowledge to prevent/reduce tornado losses. A summary report on the tornado strike compiled from online sources is available through the Wind Hazard Damage Assessment website.
Sponsored by a National Science Foundation RAPID grant, faculty and students from nine different universities, including the University of Florida, are collaborating to assess the damage to residential structures. The primary objectives of the deployment are as follows: 1) Determine whether recent past tornadoes influenced building practice to better withstand tornado loads; 2) Determine whether social media and engineering can be combined to influence future building practice.
Updates on the deployment will be regularly posted to this page. The results of this study will be freely available, similarly to that from the Tuscaloosa, AL and Joplin, MO studies. Additional photos can be found via twitter @drouecheUF.
If you have geo-tagged photos that you would be willing to share with the scientific community to help in assessing the damage and to aid in future construction efforts, please visit the Oklahoma Storm Damage Research website or send your photos via twitter to @OKStormResearch.
Damage Assessment Team
Day 6 (May 30, 2013)
Team has wrapped up damage assessment to residential structures and is on their way back. Below is a preliminary map of the rated damage, an updated map and summary of findings of the team will be coming soon.
Dr. Prevatt will remain in town with a several others to investigate the failures of schools and commercial structures under a second research grant. Particular attention will be given to the Briarwood and Plaza Towers elementary schools.
Day 5 (May 29, 2013)
Dr. Prevatt has joined the team this morning. Prior to leaving Gainesville last night he had a chance to speak with Trent Kelly from WCJB TV-20. The interview can be seen here.
As the teams began their assessments this morning, Dr. Prevatt snapped this photo of the wall construction of an upper-income residential home built in 2004, estimated worth of $350,000.
While the brick veneer suggests quality construction, the use of 1/2″ polyiso insulation board rather than structural sheathing significantly weakens the capacity of the entire structure and provides minimal support to the brick veneer. As a result the brick veneer had collapsed in many places. The hidden weaknesses in this structure are there by design, and as a result damage from a violent tornado are to be expected. What have we really learned from past tornadoes if we keep building back the same way?
Day 4 (May 28, 2013)
The teams have again deployed to the field to continue damage assessments. One team is assessing damage along S May Ave, an area that was also significantly impacted by the 1999 F5 tornado. Two photos below illustrate the power of tornadoes.
Day 3 (May 27, 2013)
Four damage assessment teams left the hotel around 7.30 am for data collection. The approximate tornado path was divided into grids for each teams to conduct visual damage assessment. Gathered data consisted of geotagged photographs of the damage and hand written notes depicting specific construction techniques and failure patterns. UF Graduate Student Austin Thompson was assessing damage to residential homes in an area about a mile east of Warren Theater. His thoughts on the damage are as follows:
“Shocking scenes from today’s damage assessments begin to play again in my mind as we finally settle down after a long day. I have never experienced such catastrophic destruction. It was tough to see people in chaos as their homes are gone, but knowing that our work has the hope of preventing such high degrees of damage in the future was a helpful encouragement. I honestly had not expected the craftsmanship in construction to be so low and the connections used to be so seemingly non uniform. Some common “mistakes” I came across were anchor bolts with no nuts or washers, rafters spaced too far apart, and a lack of clips and straps. One house merely anchored the studs by nailing them into the concrete slab. Additionally, coming from Florida, I was more expecting to see damage effects similar to those of a broad sweeping hurricane as opposed to the concentrated paths of destruction I saw today. There was a stark contrast in damage seen on houses only blocks apart. One house would be in ruins and then you go four houses down to see only some shingles missing and a fallen gutter. All in all, it has been an eye opening experience, but I am learning a lot and really enjoying my work. I believe I will find my work more rewarding after see the effects of it today.”
This photo is of a home built post-2000. Although the brick facade suggests quality construction, the team noted that toenail connections were used to attach the rafters to the wall. In other homes destroyed, it was noted that while anchor bolts were typically used to attach the wall plate to the foundation, often the nut and/or washer was missing, significantly weakening the connection. A home is only as strong as its weakest link - the importance of maintaining a continuous load path cannot be overstated.
The team will continue damage assessments in the morning.
Day 2 (May 26, 2013)
The UA and UF teams left from UA campus at Tuscaloosa, AL around 7 am. Both teams (3 vehicles total) arrived in Norman, OK around 6.30 pm. The damage from recent tornadoes on outskirts of Norman was observed. The reconnaissance started at 8 pm. Faculty and students met to discuss the logistics of the operations and formed 5 separate teams to map the area beginning May 27.
Day 1 (May 25, 2013)
The day started early around 6 am with the preparation of one of the “tornado chasing” trucks, a turbo diesel truck modified for rapid deployments and harsh environmental conditions. Part of the UF team deployed from Gainesville FL at 10.26 am, with Dr. Agdas, graduate student Austin Thompson and undergraduate student JD Doreste. Dr. Prevatt will join the team on Tuesday, May 28. The first destination was Tuscaloosa, AL to meet with Dr. Andrew Graettinger, stay overnight and then head out to Norman, OK; which is the main base for the damage assessment team.
We made it to Tuscaloosa around 6pm and were greeted by Dr. Graettinger upon our arrival. Following a quick meal at one of the local restaurants, we did quick tour of the tornado path and observed the reconstruction efforts in Tuscaloosa, AL. Around the tornado path, we also observed different levels of damages to different structures that had still not been repaired. Partial roof/external wall failures, flown off shingles etc. Discussions with Dr. Graettinger also reflected a rather unpleasant side of the reconstruction efforts, the disputes between the insurance companies and home owners. Quite a few damaged buildings were yet to be repaired, mainly due to on-going disagreements between parties.
We came back to the hotel after the brief tour to rendezvous with UA and MI teams led by Dr. Graettinger and Dr. Laura Myers to depart for Norman.