Hi Tech Industrial Services used Hydro demolition as the preferred technique, to remove concrete from around the reinforcement within an existing slab. This method of demolition allowed the concrete to be removed without any damage to the reinforcement, allowing for lapping of reinforcement to tie in a new stair well to the slab.
The lap length required was 1000mm. A high pressure unit with two operative were allocated to the contract to complete the works. Extreme care had to be taken with regards to screening of the works in order to contain the debris generated by the cutting process as the works were in close proximity to glass panels. Hi Tech successfully removed the concrete using a hand held cutting lance.
For larger areas, Hi Tech utilise there in house robotic equipment, however a hand held lance was selected for this job as multiple small locations required cutting with a combined area of 4 – 5m³. Typical hand lance outputs are between 0.6 and 1.2m³ per 10 hour shift as opposed to 4 – 5m³ in the same time using robotic equipment.
Benefits to Hydro Demolition Hydro Demolition is a technique used for the controlled removal of concrete from any physical structure using either High Pressure (HP) or Ultra High Pressure (UHP) water jets. There are many benefits to hydro demolition when compared to conventional methods of concrete removal. This includes, but is not limited to.
Environmental
No dust pollution
Reduced noise pollution caused by setting up of resonance within the structure generated by percussive methodology
Safety
Vibration free which means there is no risk associated with hand-arm vibration syndrome
Dust free environment so no inhalation for operatives
Technical
Maintains the structural integrity of reinforced steel
Eliminates all micro cracking left behind when using percussive tools
The water used for the operation flushes all contaminants out of the concrete and surface of reinforcement, particularly advantageous when carrying out remedial works on defective structures
Reinforcement steel is prepped ready for reinstatement by the hydro-demolition operation
No additional grit blasting is required
Ability to provide precision cutting with no over brake or soffit spalling due to vibration
Challenges and Hi Tech’s Solutions
Hi Tech was faced with some challenges during the project. Hydro Demolition proved to be beneficial as it was the safest and most cost effective method of removal. On site challenges included;
Challenge
Hi Tech’s Solutions Potential flying debris in surrounding environment
Solution
After a site analysis in conjunction with our SWMS, Hi Tech supplied and fitted a surrounding encapsulation to the workable site. This eliminated the chance of debris leaving the workable area.
Challenge
Water control of 5,000L per/hour
Solution
Hi Tech ensured that a bunding and filtration system was in place to enable water to be released at a safe speed and pressure, which had no contaminants and was directed down the sewer drain.
