45 MEPSIL ROAD, DUBLIN 4

Demolition of old Lift/Stair Core during construction of new Lift/Stair Core

At the 45 Mespil Road Project we were presented with a situation where the old lift and stair core existed beside the location of the proposed new lift and stair core (see Fig.1).

In order to proceed with the works the new core had to be commenced as it was on the critical path while the old core needed to be demolished as quickly as possible so that the new build could proceed efficiently.

Fig 1. Overlay of new core construction onto demolition layout

The planning for this operation was meticulous as we were proposing to carry out demolition works at height over an area of the site where men would be working in one place i.e. not moving about. How we did that was to carry out a comprehensive Risk Assessment and to ensure that all personnel engaged in the work, as well as all other personnel on the site were fully cognisant of the total operation.

Directly over the works below we used methods that included saw cutting, coring and lifting with whole sections of the RC Structure lifted clear while intact. This reduced the risk of falling objects further away from the works below, and safely shielded behind screens we used methods that included a remotely operated Brokk.

Before any of the demolition works commenced, we first put in place a temporary works system that would ensure that the structural integrity of the retained building would be maintained. We then inducted all personnel with a series of tool box talks and formal inductions that included a walk through the proposed work zone. 

In Photo 1 the temporary works propping system can be clearly see as the RC Façade to the courtyard has been removed.

By initiating a system of staggered working hours, we were able to carry out edge coring and saw cutting as well as the lifting of structural elements when the team at ground level were on a break.

By placing a watchman at ground level in radio contact with the team at high level we cordoned the ground level area with barriers, tape and live presence and were able to carry out high level work safely.

The converse applied to the crew at ground level who were able to work directly under the works above safely while the top crew were on a break. By doing this we managed to get most of the work done simultaneously and during normal working hours.

Photo 1 - 45 Mepsil Road

In Photo 8 you will see the steel platform we used during the works. It is placed onto two steel beams that span from the floor slab into two opes cored into the opposite wall. The platform allowed us to safely access all of the lift shaft walls internally, and it was easily moved by the crane with one lift for the platform and a lift each for the two beams.

Our temporary works engineers on the project were Casey O’Rourke Associates. They carried out all of our temporary works designs including for the steel platform. All of the works carried Temporary Works Design Certificates. All of the lifts were subject to lifting plans and each concrete element was calculated for weight before being cut.

When the demolition works reached basement level, we had achieved the following:

 

  • The installation of a temporary works system that maintained the structural integrity of the building.
  • The safe and thorough demolition and removal of an R.C. Structure that had the concrete elements tested to 60N and which was a complex structure.
  • A well-managed working arrangement that resulted in Zero Accidents and Zero Incidents
  • The advancing of the project on the critical path simultaneously while advancing other elements that will ensure that timely completion of the project as a whole.

 

The works were carried out safely and well, specifically because we planned for the tasks carefully and we ensured only competent personnel were involved.

The works were supervised tightly with clear communication maintained between the operatives and the manager. The Project Team were updated regularly on progress, with feedback incorporated into the works. 

The successful completion of the demolition of the old lift/stair core proves that it is possible to carry out difficult demolition works directly adjacent to other works safely and without incident.