July 16, 2020
In the heart of Marylebone, London, the 12 story International House building was demolished to make way for RCP’s Chiltern Street residential scheme. The project consisted of asbestos removal, soft strip works and floor by floor demolition. Permanent sheet piles were placed and capped in advance of a large bulk excavation package excavation.
The Cantillon team took possession of the site as Principal Contractor. Familiarisation meetings took place with members of the local community to ensure that the demolition methodology was clearly explained with open lines of communication established between the site team and residents.
The building was stripped of all finishes and asbestos before demolition commenced, materials were sorted on site then loaded and removed for recycling and reuse. During this period, a scaffold was erected around the building and wrapped with protective sheeting in advance of structural demolition works commencing. NDV equipment was installed around the project to ensure that the team monitored and managed the impact of our works in accordance with agreed WCC limits.
Following the removal of the roof mounted plant, demolition of the roof slab commenced. Each floor was traditionally cleared of materials and using a tower crane and a dedicated redundant lift shaft, materials were processed and loaded in skips at ground floor level. A 13 tonne machine processed all materials and loaded them via Paddington Street compound gates to Lorries for recycling and reuse, 94% of all materials were recycled.
Proprietary system props were installed prior to the demolition of the ground floor, these were subsequently replaced by steel props. The props were coordinated with the follow on Main contractor’s works to ensure that they did not clash with any pre-determined service routes.
he formation and pre auguring of the lead trench around the perimeter of the basement slab was undertaken in advance of the installation of sheet piles to form the basement cofferdam. The basement excavation was then undertaken with the reduced dig in ballast and clay to form the new basement level. This included use of Zero piles at 3 locations where the basement line cut across the face of the existing retaining wall.
The capping beam was formed and utilised to support flying shore supports to remove the requirement for wailings and props within the basement. This approach allowed the follow on main contractor’s works to proceed unimpeded, gaining time and cost certainty in the ground.
Installation of structural blinding above new formation level was used as a piling mat for ground source heat pump piling and the installation of bearing piles for the construction of the tower crane bases.