Investigative Actions Taken

• Photos of the accident scene were analyzed, along with the geometric configuration of the actual accident location and the speed and direction of travel of the vehicle at the time of the incident.
• The collected debris from the stone slabs were inspected and analyzed for fracture patterns.
• The A-frames were reconstructed from the debris by matching the structural weld failures.
• The ruptures in the tie-downs were also matched back to the accident scene photos to determine the original configurations of the A-frames and the securements utilized at the time of the accident.

Determinations Made

• The securement and transportation methods utilized were not the cause of the structural failure.
• The A-frame racks were provided by the material supplier, not the hauler.
• The A-frame racks lacked adequate design, construction, and maintenance for lateral loads, relying solely on increased securement for stability.
• The inadequate welds utilized in the A-frame racks design and construction caused the failure, in combination with a lack of adequate inspection and maintenance of the same.
• The hauler had increased the securement utilized beyond industry requirements, however, this additional redundancy, beyond normal and usual requirements, did not prevent the accident from occurring.

Investigative Steps Taken

• Photos of the tree on the home, as taken prior to the tree removal, were reviewed.
• Comprehensive inspection of the home, including within the areas broken open by the tree impact, was conducted.
• Doors and windows were operated throughout the home, along with measurements capable of detecting overall building movement.
• All cracks, both interior and exterior, were photographed and mapped throughout the home.
• Cracks were separated via in-field evidence into groupings of recent cracks and historic cracks.
• Recent cracks were comparatively analyzed against the force load path from the tree strike locations to the ground.
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