Faulty design, construction blamed in roof collapse
Correction: A story in Monday's Havre Daily News print edition said
the topic of the roof collapse will be discussed at Tuesday's school board
meeting. The topic is not on the agenda, but will be discussed
at the board's next regular meeting.
The Havre High School roof collapsed on Dec. 30 because it was designed to outdated standards and was then not built up to what was designed.
That's the finding of Thomas, Dean & Hoskins, the Great Falls engineering firm that conducted a study into the Dec. 30 roof collapse.
In addition to the snow and wind, the report commissioned by the Havre School Board states that the "columns were inadequately designed to support the 30 pounds per square foot snow load required by the 1994 Uniform Building Code."
When Havre Public Schools hired Dick Anderson Construction's Great Falls office to build a slanted roof designed by Bozeman architecture firm Springer Group in 1997, the newest building codes had been set in 1994. TH&D said, "the designer stated on the cover sheet that the 1991 UBC was used for design."
"According to the cover sheet for the 1997 roof design plans, the designer only used 25 pounds per square foot for the roof snow design. This is 5 psf less than what should have been used for design."
In the structural analysis of the roof, TD&H determined that the metal deck on the roof "is adequate."
The purlins, or beams, attached to the roof were "overstressed" and "inadequate."
The vertical support beams holding the whole roof up "are not adequate to support the required dead load," the report said.
The connections between the purlins and vertical posts "by design are adequate to support a 30 psf snow load, but the connections were not constructed according to the plans."
TD&H found that some of these connections were missing nearly one- third of the required screws.
"Typically there are only (8) number 10 screws attaching the column to the purlin and track and … the 1997 plans specifically requires (11) number 10 screws. In addition, the only screws attaching the track to the purlin were those through the column web and not on the track as required."
The inspections of the rest of the building found that the roof beside the auditorium was "not adequately designed or constructed."
"The connection design should not rely on attachment to a veneer brick but should attach to the structure behind or below. Also, the contractor did not install enough screws."
The report said after the inspection found some screws that were holding the roof to the wall were missing or loose.
The report concludes by first stating that "if the snow depth reaches 24 inches or deeper it needs to be removed off the roof."
Then the engineers offer repair options.
The report deems it necessary to at least bring the roof up to the 1994 standards that the roof should have been built to.
The engineers say they have talked with Dave Peterson, the city of Havre's public works director, who handles building inspections, and he "is comfortable bringing the 1997 roof up to 1994 UBC standards.
An additional option would be to update the roof to current standards, set in the 2009 UBC.
Though the report says that for this change, "significant structural supports would need to take place on both roof systems with many lower roof support requirements that would impact the functionality of the school with additional columns, beams and support systems."
Allan Frankl, the project manager for the construction in 1997, could not be reached by deadline this morning.