Here, we’ll be discussing all hydro demolition to educate the reader on what’s involved.
Over the years, there have been improvements in the way structures are demolished. Concrete demolition is one major area as it a primary construction material used for lots of structures.
We’ll be reviewing hydrodemolition as a breakdown procedure.
As the name implies, hydrodemolition involves the use of water for demolition purposes. How possible is that? Water being jetted or blasted at high pressure does a lot to loosen concrete.
Hydrodemolition is often applied when unsound concrete needs to be demolished.
Concrete restoration projects are best performed using hydrodemolition because it leaves the rebar intact without distortion.
Hydrodemolition has found applicability across a wide range of construction projects. These range from bridge deck restorations, building repair, road repair, and sidewalk repair.
Others include fixing of parking lots and parking garage repair, as well as tunnels and silos just to mention a few.
Hydrodemolition gives a wide range of solutions as it helps remove protective coatings. Such protective coatings include epoxy and paint among others. The tip of the water jetting equipment allows for different nozzle types to be changed.
Such nozzle types include single and multi-jet nozzles.
The type of demolition job determines what nozzle type will be used. Now, hydrodemolition is very different from other traditional demolition methods involving the use of heavy machinery like bulldozers and excavators.
It’s also different from explosives used for commercial demolition projects. One of the key differences, when compared to traditional methods, is that hydrodemolition eliminates dust.
It also solves the problem of loud noise generated from demolition projects.
Advantages of Hydrodemolition
When it comes to the benefits derived from hydrodemolition, there are many of them. Its many benefits have led to wider adoption of this demolition method over more traditional ones.
The following are clear benefits of using hydrodemolition;
Low Noise and Vibration Transmission
One of the points mentioned earlier is the lower noise and vibration transmission it gives.
Unlike traditional demolition methods such as those involving pneumatic hammers, hydrodemolition allows for low noise transmission. This is best for 24-hour occupancy buildings like hotels and hospitals among others.
Cleaning of Reinforced Metal
The use of traditional demolition methods will require sandblasting rebar. The need for sandblasting is eliminated when using hydrodemolition as it does a great job of cleaning the reinforced metal.
What more? Micro cracking of surrounding sound concrete does not occur.
One of the key advantages of hydrodemolition is the faster reproduction rates involved.
While faster product rates are generally applicable to hydrodemolition projects, equipment set up and compressive strength of concrete will impact production rates.
With this benefit, construction schedules are shortened significantly. This allows for faster completion of projects.
Minimal Dust Generation
One of the key benefits of hydrodemolition is the absence of dust. The worse-case-scenario is a limited amount of dust generated. This offers a whole lot of benefits as dust-related issues don’t come up.
Also, the environment is a lot safer.
Deteriorated Concrete is Completely Removed
We earlier mentioned that hydrodemolition aims to remove deteriorated concrete. The outcome of this procedure provides an excellent result.
Old and deteriorated concrete is gotten rid of to make way for fresh reinforcement.
Disadvantages of Hydrodemolition
While hydrodemolition provides lots of benefits as mentioned above, it’s not all rosy. In other words, certain challenges are posed by its use compared to conventional demolition processes.
These challenges include the following;
Certain Parts Maybe Unreachable
There are certain parts of structures that may be unreachable for hydrodemolition. Water sensitivity may also be an issue why this type of demolition can’t be used.
The remedy for such problems may be to revert to the use of traditional demolition methods like pneumatic hammer demolition.
Significant Water Usage
One of the downsides of using hydrodemolition is the significant volume of water used.
On average, about 50 to 100 gallons of water are used per minute. This won’t be an ideal demolition technique when considering water conservation practices.
Additional Room for Fitting in Equipment
Hydrodemolition equipment needs to be moved within proximity to the demolition area.
This means the creation of ample space to keep the equipment. Now, this could pose a challenge as there could be little room left for water collection and wastewater treatment.
Series of Treatment for Wastewater Produced
Hydrodemolition produces a lot of wastewater. This isn’t disposed of but treated.
Now, such treatment involves a whole lot of processes. After collecting it, it will need to be allowed to settle, which is followed by filtration and treatment.
With treatment completed, such water needs to be pumped into a sanitary system. This is where additional work is involved as most jurisdictions will require obtaining a permit as well as testing of discharged water.
There could be limits placed on the volume of water to be discharged into the sanitary system. These processes and requirements make hydrodemolition quite a challenge.
Preparing For Hydrodemolition
Before hydrodemolition commences, it’s important to ensure that all necessary things are put in place. Such include having the required experience, logistics, water control & treatment as well as depth of cut.
What more? You’ll need to figure out the procedures for cleanup and debris removal.
Safety is a key issue when performing hydrodemolition. You’ll also need to consider fire and electrical alarm conduits in slabs.
What does a hydrodemolition contractor expect from you?
In most cases, you’ll need to provide information on proximity to a water source. The client may be required to provide fuel, a water source, as well as an adequate workspace.
Other logistic details include getting detailed results on existing concrete compressive strength. This is obtained from an engineer.
Depth of Cut
It’s important to ascertain the depth of cut even before the demolition procedure begins. The depth of cut for repairs is necessary to enhance accuracy.
As part of preparations, any additional hydrodemolition costs for increased cut depths must be obtained.
To get to the perfect depth, it’s necessary to continuously make adjustments on the hydrodemolition machine or robot. All nozzle replacements must be available to help make perfect cuts.
Safety should be of utmost concern when performing hydrodemolition.
Thankfully, there are local, state, and federal safety regulations to follow. All personnel involved in the demolition work must have on-base personal protective equipment.
Partitions need to be installed around the perimeter of the work area. The best partitions to install should be full-height wooden partitions. Unsuspecting passersby need to be alerted to the nature of ongoing work.
As such, it’s important to have proper signage erected at the perimeter of the work area.
It may be necessary to block or cordon off entryways into the work area. This should last for the duration of the demolition work. Are other tasks or jobs being performed within the vicinity?
If there are, consider placing debris protection or netting surrounding the hydrodemolition equipment or robot.
If high-pressure water lines extend into public areas, these will have to be protected against damage and accidents.
Having the Require Experience
Experience is key to performing a satisfactory hydrodemolition job. So, it’s important to find a reliable and competent hydrodemolition contractor.
In finding a contractor, you’re looking to hire one with appreciable experience in the specific area required.
You might want to begin by demanding references from clients. Also, you want to be sure that the team members involved in the project are up to the task. This requires asking for their resumes and qualifications.
It’s also important that everyone on the job is licensed.
Water Control and Treatment
One of the requirements for hydrodemolition includes having control over the water to be used within the work area. Apart from the installation of perimeter dams, deck drains will have to be disconnected.
This includes the plugging of drains found at the lower levels.
How competent is the hydrodemolition contractor in performing water treatment? How compliant is the contractor to local, state, and federal requirements? You’ll need to know such requirements to be certain.
Procedures for Cleanup and Debris Removal
After the demolition process, the debris left behind will need to be properly cleaned up.
This is performed as soon as possible. A hydrodemolition contractor should have all it takes to perform a thorough cleanup of the work area after the job is completed.
Fire and Electrical Alarm Conduits in Slabs
To ensure that critical components aren’t destroyed, it’s necessary to perform basic inspections. Such an inspection process should be with the help of an electrical subcontractor.
Temporary measures may be put in place to limit the damage. It’s best to turn off all electrical systems close to the work area until demolition is completed.
Hydrodemolition involves a whole lot of processes as seen so far. One of the primary things to consider is hiring the best hands for the job.
We’ve also seen that this procedure has a lot of advantages compared to traditional demolition techniques.