Review of the damage from the May 22 tornado in Joplin revealed the big box stores that collapsed had used the popular "tilt-up wall" construction. The common use of such construction on large buildings led Monett R-1 school officials to investigate whether Monett schools were vulnerable to similar collapse.
According to an investigation by the Kansas City Star, tilt-up wall buildings are erected with concrete walls poured on site and lifted into place with cranes. The walls are held upright by critical connections to a relatively lightweight roof system.
If the roof becomes compromised under high winds, the panels in tilt-up wall buildings can fall like dominoes, said Larry Tanner, a tornado expert for the Federal Emergency Management Agency (FEMA) who traveled to Joplin to study the Home Depot collapse and other building failures.
Tilt-wall design has been widely used in constructing large buildings like schools. Pam Haldiman, an architect with Sapp Design Associates, reviewed the Southwest Area Career Center, Monett Intermediate School and the new addition at Monett Elementary, all of which Sapp designed for the R-1 District.
"The project at the elementary school is 'precast' and not 'tilt-up.' They are two different methods of construction although they may look similar in appearance," Haldiman said. "Because of the similarities in appearance of the precast walls at the Monett Elementary FEMA Shelter and the tilt-up concrete panels, which the media has indicated was the construction type of the Home Depot, a discussion of the current construction project may be warranted.
"Part of the current construction project at the elementary school incorporates a precast concrete wall system and a precast concrete double T roof structure that will function as a safe room for the elementary school and surrounding residents," Haldiman continued. "This structure has been designed in accordance with FEMA to withstand 250 mile per hour winds or the equivalent of an EF-5 tornado."
According to Haldiman, the strength of the structure meets debris impact criteria set by FEMA.
"The use of the precast concrete walls in concert with the precast concrete roof system and its structural connections allows the structure to resist both uplift and high winds as well as debris impact," Haldiman added.
The type of roof structure used at Monett Elementary and the lateral support and structural connections appear to be significant differences between the construction style used at the Home Depot and the school.
Superintendent John Jungmann contacted Branco Enterprises, the contractor that built the high school, to assess the older construction.
"I was able to confirm today that there is no 'tilt-up' construction at Monett High School," Jungmann said. "That facility was constructed with standard block construction, as was the Career Center.
"Even standard block construction is not designed to withstand the forces of an F-5 tornado like the one that hit Joplin," Jungmann said. "The only district location that would be designed to handle these types of winds would be the new FEMA shelter at the MES campus."