Work performed
- Structural inspection of the roof and desk study
- Development of the methodology
- Clearing of waste material
Scope
The partial collapse of a cement mill roof prompted an immediate roof cleaning exercise. Alongside the response to the collapse itself, TALOS was required to clean the remaining roof to reduce the dead load from caked cement.
A drone inspection showed the risk level and the amount of material on the roof, and led to a method using rope access technicians — the safest way to work on that roof.
Access
Approaching the roof without a secured lifeline was deemed dangerous. Using the drone survey to plan the work areas, scaffolding towers were erected on opposite sides of the building and lifelines were attached across them.
Solution
TALOS first demolished the collapsed section and separated it from the remaining roof. One team removed the rubble with two mobile cranes — one with a man-basket, the other hoisting metal roof sections — while the rope access technicians cleaned the remaining roof.
Over several years the roof had accumulated cement and clinker dust that had hardened to a thickness of 20 to 500 mm. Working from the scaffolding towers and lifelines, technicians broke it up with electric rotary and pneumatic hammers, scraped the rubble down for disposal, washed off the remaining material with a high-pressure water jet and replaced all damaged roof sheets.
Results
The roof was cleaned safely and successfully, removing the unexpected dead load and reducing the risk of further collapse. Cement plant roofs should be cleaned periodically: settled dust can compromise structural integrity and lead to collapse.