Texas Tech University

Tornado Debris Impact Testing and Masonry

Structure

May 1, 2018

Structure - Those of you who have had an opportunity to work in jurisdictions that have adopted the 2015 International Building Code (IBC) should have noticed a significant change related to mandatory tornado shelters in a significant portion of the Central U.S. For areas that use the 2015 IBC, this new requirement will impact the majority of new school and emergency facility construction spanning as far north as central Minnesota, as far south as southern Mississippi, and stretching to western Pennsylvania in the east and western Texas to the west. This area is shown in Figure 1 and is where tornadoes with wind speeds of at least 250 mph have a history of occurrence.

Because schools and emergency facilities frequently use partially grouted, masonry cavity walls (especially in the regions encompassing most of the ICC 500's – 250 mph wind zone), questions were raised as to whether a masonry cavity could provide sufficient debris resistance, even if the backing wall was not fully grouted. A testing program was developed and executed as described below to answer the question.

Two different wall configurations were developed and designed to be representative of clay brick and CMU cavity walls used in conventional exterior walls for schools.

Each of these specimens was tested at the Wind Testing Laboratory at Texas Tech University in Lubbock, Texas.

Read the story here.