The City of Davenport announced the completion of the “causes and origins report” from the partial building collapse at 324 Main Street in May. The findings were released by the city Thursday after an investigation by SOCOTEC Engineering and White Birch Group LLC.
The bodies of Branden Colvin Sr., Ryan Hitchcock and Daniel Prien were recovered from the site several days after the collapse.
According to the report, the root causes of the collapse were an “inadequate capacity of wall system” and “inadequate shoring.”
“The removal of multiple wythes of masonry during the repair work in the three days preceding the collapse severely compromised the western bearing wall and caused it, as well as the areas it supported, to collapse on May 28, 2023,” the executive summary of the report stated. “The temporary shoring that had been installed was grossly inadequate. Had a proper shoring and construction phasing plan been implemented during these repairs, the building would not have
partially collapsed on May 28, 2023. The temporary stabilization methods specified by the Design Professionals during various repair projects for the building do not appear to have considered that the western wall served as a critical structural load bearing element. Additionally, the shoring implemented by the most recent masonry repair contractor at the subject building does not conform to usual and customary practices for masonry wall shoring or stabilization.”
“The driving force of the partial collapse is the overstress that developed in Piers C and D, which resulted in their inability to support the loads imposed from the floors above. This can be considered the triggering event,” the report said.
The report also stated the installation “was severely lacking in multiple aspects”:
- The shoring did not engage any masonry other than limited portions of the exterior wythe.
- The spacing of the shoring was inadequate given the extent of the brick removal.
- The shoring members were severely undersized.
- The shoring was inadequately restrained at both the top interface with the wall and the bottom interface with the pavement.
- While there are multiple proximate and interrelated causes as noted below, the resultant condition of the wall created by the improper implementation of the late May 2023 repairs resulted in the collapse incident.
The report also listed proximate causes of the collapse, including “improper understanding of original building construction, inadequate construction documents, neglect of composite wall, inadequate oversight of repairs, inherent weakness of west wall, inadequate repair techniques and inadequate frequency and type of maintenance.”
The report said documentation from Select Structural Engineering “does not mention a review of the original construction drawings” and “the reports and letters produced by SSE contain multiple contradictions, questions, and improper assumptions regarding the composition of the subject Building’s structural system.”
- February 2, 2023: “It is unclear whether it bears on the brick wall directly or rather on a steel column encased in brick.”
- February 8, 2023: “The clay brick wall appears to be three or four wythes thick.”
- February 8, 2023: “It is unknown if there is a north south steel beam inside the wall at the second floor level, or if there is a steel post encased in the brick…”
- February 8, 2023: “It will therefore be conservatively assumed that the east-west beams bear directly on the brick wall to be replaced.“
- February 28, 2023: “This will soon cause a large panel of façade to also collapse, creating a safety
- problem and potentially destabilizing the upper areas of brick façade.”
- May 24, 2023: “…several large patches of clay brick façade which are separating from the substrate. These large patches appear ready to fall imminently, which may create a safety hazard to cars or passersby.…the brick façade above the windows should be secured. This is to keep the entire face of the building from falling away when the bottom area(s) come loose.”
“SSE violated the standard of care by misidentifying the composition, thickness, and load-bearing nature of the wall throughout its nearly four months of intermittent engineering assessment and brick replacement projects at the Building,” the report said.
The report also includes of repair work at the building since 2020, including from before the bricks were painted red.
The full report can be found below, by clicking here and on the city’s website. Local 4 News reporters and producers are currently reading through the 113 pages of the report and will update this story as more information becomes available.
“Since the day of the partial collapse at 324 Main Street, we have been laser-focused on identifying the causes of this tragic incident,” said Mayor Mike Matson in a news release announcing the report’s completion. “We engaged the services of the consultants who responded to the Surfside condominiums collapse in 2021 and we promised the public we would share their findings. Today, we are following through on that promise. Our hearts and thoughts remain with the families of Ryan, Branden, and Daniel and their loved ones, friends, and neighbors.”
Local 4 News requested an interview with the city Thursday after the release of the report, but that request was denied.