ASSISTANCE FOR THE CORELOC™
PRESENTATION OF THE CORELOC™ BLOCK
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The CORELOC ™ block was patented in 1995:
The CORELOC ™ block is very similar to the ACCROPODE ™ in that it consists of four legs and two noses:
CORELOC ™ LEGAL SITUATION
CORELOC ™ was patented over twenty years ago.
The CORELOC™ trademark has been registered by the US Corps of Engineers (USA).
CORELOC ™ has fallen into the public domain.
INSTALLING THE CORELOC ™ BLOCK
Contacts with lower rank CORELOC ™ must be established with solid support.The main obstacle to this good interlocking is due to the attachment of the CORELOC ™ to the riprap of the sub-layer which stops the movement down the block. The only way to get over this constant problem is to visually ensure that the block is in its final nesting position. In about 40% of cases, a natural installation will lead to poor nesting and the CORELOC ™ thus installed will still have the possibility of further descending under the action of its weight and / or the sea.
Changing the orientation of the blocks does not eliminate this problem. Only a visual check of each block when it is adjusted between the two CORELOC ™ of the lower row allows this, subject to mastering the principle of nesting and the inspection procedures.
Appearance of a correctly placed CORELOC ™ armor
The supports with the lower row are well established. There are no contact faults.
The orientations of the blocks are varied. No CORELOC ™ can descend or oscillate. There are no holes. There is no CORELOC ™ off profile.
During the various projects that we have carried out with the CORELOC ™ we have found that it is more sensitive to shocks than the ACCROPODE ™. As with the ACCROPODE ™ II, avoid shocks. The interlocking must be perfect to avoid movements after installation, which may cause breakage.
With the CORELOC ™ we cannot repair interlocking defects without removing the blocks. Every time we tried to do it we brake the block.
MOST COMMON PLACEMENT DEFAULTS
CORELOC ™ out of profile
Possible origin
Defect of the underlay, insufficient training of installation teams, installation error, ineffective installation control.
Risk
An off-profile CORELOC ™ can be extracted by a strong swell. In its fall it risks breaking the CORELOC ™ below and its extraction will cause a large hole. A single CORELOC ™ out of profile which is extracted can initiate unraveling of the shell in the affected area and lead to a major disorder.
Required action
Disassemble the area and correctly nest the CORELOC™. If the origin of the nonconformity is a defect in the underlayment, the underlayment must be adjusted before re-installing the CORELOC™.
CORELOC ™ mounted in columns
Column mounting is not indicated as a non-compliance in the technical reference published by the license vendor. The reference system mentions compliance with the diamond mesh and tolerates occasional deviations. However, we have found that the columnar assembly of CORELOC ™ produces movement and breakage and must be corrected. That’s why we’re mentioning it.
Possible origin
The technical repository of the license vendor authorizes occasional non-compliance with the installation mesh and this favors the appearance of this type of problem. However, it is also indicated that the CORELOC ™ must be interlocked between them and not have freedom of movement. The installation in CORELOC ™ columns which have freedom of movement is attributable to insufficient training of the installation teams, an installation error, ineffective control of the installation.
Risk
CORELOC ™ mounted in columns are generally unstable and do not have the right downforce with the lower row. They are generally not properly blocked by the CORELOC ™ of the higher rank. They will move and possibly break. If they do break the area will start to unravel and will need to be rebuilt.
Required action
Normally the area mounted in columns should be dismantled and these CORELOC ™ correctly positioned respecting the laying mesh. CLAS has know-how that allows this type of non-compliance to be resolved without dismantling the CORELOC ™ above, in the majority of cases.
CORELOC ™ poorly interlocked
Possible origin
A poorly interlocked CORELOC ™ generally got stuck to a riprap in the embankment and did not descend to its final interlocked position. This concerns about 40% of CORELOC ™ placed "naturally" on the target position. The cause is attributable to insufficient training of installation teams, an installation error, ineffective installation control.
Risk
Poorly interlocked CORELOC ™ are unstable and do not have the right supports between them. They will move and possibly break. If they do break the area will start to unravel and will need to be rebuilt.
Required action
Normally the area should be dismantled and these CORELOC ™ correctly positioned respecting the laying mesh and the strong supports with the CORELOC ™ of the lower row.
CORELOC ™ broken
This CORELOC ™ is broken in place following an impact. Without a seasoned diver this problem cannot be detected underwater.
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When we remove this CORELOC ™ we see that the broken piece is important and this block was no longer participating in the interlocking.
Possible origin
The quality of the concrete should be checked first. If the quality of the concrete is not in question, the cause is then linked to a movement of the CORELOC ™ due to poor interlocking during installation. The cause is then attributable to the insufficient training of the installation teams, an installation error, the ineffective installation control.
Risk
When broken CORELOC ™ no longer participate effectively in ninterlocking, the area begins to unravel and will need to be reconstructed.
Required action
The action required depends on the position of the broken CORELOC ™. For example, a CORELOC ™ in the first row which has been broken by rockfill from the toe stop, but which is properly blocked, should not be replaced. If the broken CORELOC ™ is in the middle of the shell and no longer participates in theinterlocking of the area, then the area must be dismantled and the broken CORELOC ™ replaced.
Holes
A hole can be recognized by the fact that the riprap from the sub-layer could be extracted through this hole.
Origin
Insufficient training of installation teams, installation error, ineffective installation control.
Risk
The underlayer rocks that we see can be split and mined. There is a risk of the area moving causing the CORELOC ™ to break, which will then initiate the unraveling of the armor.
Required action
It depends on the position of the hole. An isolated hole in an otherwise properly constructed area can be plugged with a bag of concrete, for example, provided that once installed the bag of concrete cannot be extracted. If this is not possible, or if the hole is close to the surface, the area must be dismantled and the CORELOC ™ re-installed properly.
CORELOC ™ placed with the nose in the slope
Origin
Insufficient training of installation teams, installation error, ineffective installation control.
Risk
This type of positioning can cause movement and therefore breakage of CORELOC ™. The breakage of CORELOC ™ initiates the gradual unraveling of the shell.
Required action
Usually the area must be dismantled and the CORELOC ™ refitted. CLAS has the know-how that allows this type of non-compliance to be adjusted without dismantling in the majority of cases.
CORELOC ™ placed with the anvils facing the sea
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Origin
Insufficient training of installation teams, installation error, ineffective installation control.
Risk
This type of positioning favors crossings. This creates an obstacle and severely limits the flow of water in the shell, with the risk of causing the breakage of the CORELOC ™ in this area, under the blows of the swell.
Required action
The area must be dismantled and the CORELOC ™ reinstalled.
Other installation faults may occur more rarely. Our inspectors will help you understand and resolve them.
PLACING SPEED WITH CORELOC™
The rate of installation depends on the following factors:
- Size of the blocks: The bigger the block, the more difficult it is to move and the more it is subject to breakage in the event of an impact.
- Placing machines: The hydraulic excavator allows an installation rate almost doubled compared to the cable crane,
but its use is limited by the weight of the CORELOC™ and the installation distance.
- Quality of the underlayer: an underlayer that does not respect the tolerances and has significant roughness will slow down the laying and limit the possibilities of interlocking the blocks.
- Quality of the training of the installation team: a good theoretical and practical training which includes training in safety, the CORELOC ™ technique and the gradual increase in the installation rate, lasts about one month. It is not just training, it is learning that obeys educational rules and progression that can only be taught by construction professionals.
- Visibility: good visibility will facilitate visual inspection operations. The operator must be able to see the armor from the front, perpendicular to the slope surface, and receive information on the points of contact with the CORELOC ™ in the lower row and with the slope. Only a diver can properly carry out these checks. In clear water it is very fast, in dirty water it takes longer and requires extensive learning, especially in safety.
- Installation tools used: There are three ways to install:
1 Divers is the fastest and most reliable system.
The CORELOC ™ license vendor recently wrote about this:
"A diver or camera control to see the interlocking of each block is necessary. It is essential that these checks take place regularly, several times a day if necessary. "
Divers with cameras allow better interlocking than any other system. "
2 The POSIBLOC ™ is the system that we consider the slowest and the least reliable because it is based on the theoretical position of the block in X, Y, Z and not on the interlocking, which is the opposite laying rules, which favor interlocking without tolerance limits with respect to the target. On the other hand the system shows a virtual image to the operator which is often different from the reality, due to the imprecision of the system.
The software uses colors to indicate to the operator whether the block is on target or not. The operator is trained to pose according to the right interlocking and not according to the target. It will therefore rely on the contacts shown by the software, while trying to respect the colors. Unfortunately, the imprecision of the system does not allow us to have a reliable representation of reality:
The blocks are in contact on the image provided by the software, they are not in reality.
Conversely here the blocks are not in contact on the image and are in reality.
3 The ECOSCOPE ® is an acoustic system which increases the rate of installation in dirty water but cannot be dispensed with a check by plunger, because once the block is installed, the image does not allow not to appreciate the quality of the contacts with the CORELOC ™ of the lower row, nor the interlocking and installation defects.
The ECOSCOPE ® may also show holes and interlocking defects that do not exist. This is due to the artifacts that can often appear with acoustic tools like ECOSCOPE ® or multibeam sonar.
- Quality and frequency of installation checks: The longer we delay the frequency of checks, the more we are exposed to major dismantling which will seriously penalize production. It is no use giving yourself the means to install 10 CORELOC ™ per hour if you have to dismantle 50% at the end of the day.
More than the hourly installation rate, it is the frequency and quality of inspections that will allow production objectives to be achieved. Very close checks, by divers, will make it possible to eliminate dismantling by limiting the treatment of installation faults to real-time adjustments.
On the contrary, a multibeam sonar check after the installation of several rows, will not make it possible to see all the installation faults and will require significant dismantling in the event of additional control by divers. In the event that only the multibeam is implemented, the quality of the construction cannot be certified in CLASS A. The durability of the work cannot be guaranteed.
The average production by cable crane laying with CLAS trained divers is 6 to 8 CORELOC ™ per hour, approved.
The average hydraulic excavator production with CLAS trained divers is 12 to 15 CORELOC ™ per hour, approved.
These statistics, derived from site data, include one-off dismantling.
OUR EXPERIENCE WITH THE CORELOC ™ BLOCK
BARAKAH NUCLEAR POWER PLANT ABU DHABI 2013
110,000 CORELOC ™ of 1 m3.
The POSIBLOC ™ installation did not work as expected by the NMDC company. The IDMer company was called in to make up for the delays and rectify the installation faults.
The inspectors of IDMer, now CLAS, properly trained the installation teams and supervised the work. The delays were made up and the installation of CORELOC ™ accepted by the customer without reservation.
Commentaires de NMDC
Link reference BARAKAH NUCLEAR POWER PLANT Expertise
Link reférence BARAKAH NUCLEAR POWER PLANT Construction
AL ZOUR KUWEIT 2016
17,000 CORELOC ™ of 1 m3.
VAN OORD was to build a new port for the Al Zour refinery in Kuwait.
CLAS has trained all personnel responsible for the installation of CORELOC ™ and has certified the quality of the installation CLASS A certification.
We have achieved a production of more than one hundred CORELOC ™ correctly installed per 24 hours, with a single installation station. The project was delivered on time and approved without reservation.
Commentaires de van Oord
Link reference AL ZOUR Construction
Link reference AL ZOUR Certification
AL FAW IRAQ 2017
The DAEWOO company was to build a new port near BASSORA. At the request of CLI, CLAS, becoming a CLI agent for the duration of the mission, provided DAEWOO training on site for one month.
After a month of training and training, we brought the installation teams to a production in sight of 15 CORELOC ™ correctly installed per hour on average. This enabled DAEWOO to lay around 90% of the CORELOC ™ at low tide and to complete the work early.
Comments from DAEWOO
