Construction Week Middle East's video: Modon Properties Bill O Regan on the World Record Mina Plaza demolition

On Friday, 27 November 2020, teams from the Abu Dhabi’s Department of Municipalities and Transportation (Abu Dhabi DMT) implemented demolition activities to bring down the four-building Mina Plaza towers in Abu Dhabi – claiming a Guinness World Records™ title, as one of the four buildings, Tower 1, which stood a 165.032m in height, was determined to be the “tallest building demolished using explosives”. In this episode of Construction Week's Expert Interview series, the chief executive officer of Modon Properties, Bill O'Regan – who spearheaded one of the biggest blowdowns the world has seen in the last five years – speaks to Construction Week's deputy editor, Anup Oommen, about the preparatory phases, the safety precautions, the insurance procedures, and the various phases of the Mina Plaza towers demolition. Commenting on the reason behind the demolition, Bill O'Regan, says: "Initially, the Department of Municipalities and Transportation looked at re-master-planning the Mina Zayed area in Abu Dhabi. Through that exercise, it was determined that a low-density development was appropriate for the Fisherman's Wharf area. Mina Plaza, which started construction in 2008, really didn't fit with the new vision." "It was at that point that the Abu Dhabi DMT appointed Modon Properties to clear the entire site, including the buildings existing on the Wharf, warehouses, temporary buildings, and the like. We also studied the demolition of Mina Plaza towers itself." Modon Properties worked closely with US-based demolition engineering consultant ASI to completely remodel the Mina Plaza towers based on the as-built information rather than the original design. "Based on the new as-built design model, we looked at reverse engineering for the demolition of the building through multiple methods, including mechanical demolition and controlled implosion," O'Regan adds. The Mina Plaza Towers project consists of five structures, including the podium and the four towers that rise from the podium. Since the buildings are all interconnected, it is near-impossible to bring down one without having an impact on the others. Approximately 750,000 safe man-hours were logged to initially construct the Mina Plaza towers project, which was demolished in under 10 seconds through a "controlled implosion". O'Regan says: "What was really incredible to see on Friday was that the buildings came down exactly as simulated. The simulation is always just that - a simulation. But the level of engineering work, and the level of planning that went into this, really came through with the buildings falling exactly as we had planned and as we had hoped for." The demolition was carried out in three phases. Phase 1 of the demolition included a strip-out of the buildings, which involved removing any part of the buildings that could be removed, including the facade, the MEP installations like the pipes, and the elevators. Phase 2 involved the preparation for the charging. More than 18,000 holes were drilled into the structural members of the building, where the explosives needed to be placed. Certain parts of the buildings also needed to be cut and weakened to catalyse the demolition. Phase 3 comprised of the "charging of the site" – which meant bringing the explosives onto the site – including the combination of plastic explosives for the larger structural members, and detonator cords for the more slender structural members. "We successfully completed the charging of the building on 19 November 2020, which allowed us to spend a week in checking, double-checking, and triple-checking that everything was in order," O'Regan explains. "It was that level of scrutiny that helped us stay calm, knowing that we had taken all the measures possible to make sure that what we were doing was safe." Modon partnered with several stakeholders to carry out this project, including Abu Dhabi Police GHQ, Abu Dhabi Civil Defense, the National Crisis and Disasters Management Authority, emergency response teams, and other committees. Precautionary measures for the world record demolition included the evacuation of the area surrounding the towers; provision of ambulances, emergency, and fire and rescue vehicles; as well as confirmation of the civil defense’s readiness with high responsiveness. "The initial exclusion zone was approximately 500m in radius. Just before the blowdown, the radius was expanded to 1.2km. We kept out all traffic, shut down all of the roads, closed the airspace above the buildings, and ensured that nobody was in the area during the demolition." O'Regan concludes: "You have 3 things to be cognizant of: the physical debris, the powerful sound wave, and the dust. Thankfully, Mother Nature helped us out on Friday: the most favourable model to deal with the dust was an offshore wind, and that's exactly what we got on Friday morning, as the dust was blown over the empty land in Mina towards the sea." Watch the video today! :) © ITP MEDIA GROUP