Diamond Award 2022

It was decided to divide the work into 3 zones:

• Intermediate zone (A) 7 spans x 10 panels x 2 sides = 140 units.
• Extreme zone (B) 7 spans x 2 panels x 2 sides = 28 units.
• Central zone (C) 7 spans x 1 panel x 2 sides = 14 pcs.
  + aerator

The work would be carried out span by span, adopting a different solution for each of the areas.

Safety is never negotiable: workers must be protected, above and below.
At the top of the deck, 2 longitudinal lifelines will be provided, one on each side.
In turn, transverse lifelines will be placed, where the retractable reels that connect to each worker’s harness will be hooked.
In addition to the usual PPE, each worker will be equipped with a gas detector and a mini-exhaust mask.

At the bottom, it is decided that it is best to build a working platform on top of the bridge crane.
It is sized to occupy an entire span (7 meters wide), and is calculated to withstand the impact of a falling concrete panel.
The fact that it is built on the bridge crane will allow it to be easily moved as the work progresses.
Each time a span is completed, a safety net is installed.

In the central area, the elements to be removed are two concrete U-panels and the metal aerator.
The wire-cutting technique will be used to fragment and separate the aerator.
As the element is free on both sides, it was decided to remove the three elements together.
A mesh of slings, chains, eyebolts, net and tarpaulin is designed to remove the whole safely.

At the end panels, the designed tool could not be used, since it needed an entry space for its positioning.
The solution devised is to design and build an aluminum/wooden bed to serve as a supporting structure for the panel.
In addition, an exterior tarpaulin will be provided to cover the removed panel to prevent possible detachment.
This bed would be placed on the adjoining panel, but supported only on its ends (truss), so as not to transmit loads that could cause collapse.
The panel to be removed would be lifted a few centimeters and would have a minimum lateral displacement (less than one meter), to be placed on the supporting structure.
HILTI HUS3-H mechanical anchors, specially designed for cracked concrete, and anchor plates designed and certified by RE-CORTA are used for lifting.
The holes for inserting the anchors are drilled with diamonds, by rotation, to avoid vibrations.

The idea is to design, calculate and manufacture an element that allows:

1. Serve as a frame for the placement of a cordless cutting machine.
2. Serve as a support element for the entire panel, avoiding any possible detachment during all phases of the execution of the work (cutting, lifting, moving and lowering).
3. Do not transmit loads to the deck

A replica of two wooden panels is made, with the real inclination of the roof, to carry out the design of the tooling.

…and it takes shape!
In addition to the above, it is equipped with:

1. A movable hook on the upper part, to adjust the center of gravity
2. A lifting element for raising and lowering the cutting machine.
   In the up position for positioning the tool and removing the panel, and in the down position for the cutting operation.
3. A scale, for adjusting the initial tension of the crane
4. Slings, to secure the panel fixation

The tool is built in close collaboration with a specialized company, which carries out the calculation, manufacture and approval of the tool.

The cutting machine of choice is the HILTI DST 20-CA saw (20 kW).
It is one of the most compact and powerful wall sawing systems on the market.
Unlike all the others, the power unit is built into the cutting head itself, making it easy to install in the tooling.
On the other hand, it is an equipment that can be operated by remote control, with the operator placed in a safe area.

In the central area, the elements to be removed are two concrete U-panels and the metal aerator.
The wire-cutting technique will be used to fragment and separate the aerator.
As the element is free on both sides, it was decided to remove the three elements together.
A mesh of slings, chains, eyebolts, net and tarpaulin is designed to remove the whole safely.

At the end panels, the designed tool could not be used, since it needed an entry space for its positioning.
The solution devised is to design and build an aluminum/wooden bed to serve as a supporting structure for the panel.
In addition, an exterior tarpaulin will be provided to cover the removed panel to prevent possible detachment.
This bed would be placed on the adjoining panel, but supported only on its ends (truss), so as not to transmit loads that could cause collapse.
The panel to be removed would be lifted a few centimeters and would have a minimum lateral displacement (less than one meter), to be placed on the supporting structure.
HILTI HUS3-H mechanical anchors, specially designed for cracked concrete, and anchor plates designed and certified by RE-CORTA are used for lifting.
The holes for inserting the anchors are drilled with diamonds, by rotation, to avoid vibrations.

In the central area, the elements to be removed are two concrete U-panels and the metal aerator.
The wire-cutting technique will be used to fragment and separate the aerator.
As the element is free on both sides, it was decided to remove the three elements together.
A mesh of slings, chains, eyebolts, net and tarpaulin is designed to remove the whole safely.

Once the demolition work was completed, work began on the installation of the new lightweight sandwich panel roof on metal purlins.

All of the extracted panels were taken to an authorized landfill.
There, the insulation was separated from the panel and, in turn, the reinforcement from the concrete itself, managing the concrete and recovering the metallic elements (reinforcement and aerator).
The volume of panels per transfer unit has been maximized, taking into account the space available for stockpiling, saving costs and reducing CO2 emissions into the atmosphere.

RE-CORTA combines more than 30 years of experience in the field of technical demolition.
The beginnings were linked to diamond hollow core drilling.
Later on, the leap was made to cutting: first with discs and then with wire.
The last step has come with the demolition with teleoperated robots and auxiliary breaking systems.
The result of all these years makes it possible to face any type of technical demolition in industry, building or civil works, with sufficient guarantees.
The work that concerns us has been developed within a factory, where the working conditions are certainly particular, without stopping its production process, requiring a precise plan of coordination of business activities, calculated down to the smallest detail.

A new phase of the works is currently underway, which will affect an area of 2,310 m2 (416 concrete panels).
The completed phase is shown in green, and the phase in progress is shown in red.

Referring to similar works, in 2016 the removal of the facade of El Corte Inglés de Las Palmas II, consisting of very deteriorated prefabricated concrete panels, had already been undertaken.
The work was carried out on one of the main avenues of the Canary Island town, without cutting off traffic or pedestrian traffic.
On that occasion, 437 panels were removed.