Concrete Cutter Repairs Pier at Guantanamo Bay Naval Station
One CSDA member recently traveled to Naval Station Guantanamo Bay to cut and remove an old concrete pier and returned several months later to resolve a critical issue with the new pier construction. The job involved core drilling six 18-inch-diameter, 7.3-foot-deep holes in concrete pipe piles using diamond tools.
Naval Station Guantanamo Bay, Cuba (also known by the designation code GTMO and pronounced “gitmo” by the U.S. military) is on the front lines for regional security in the Caribbean area. The base supports the ability of U.S. Navy and Coast Guard ships, along with allied nation ships to operate in the Caribbean area by providing contingency and quality logistical support with superior services and facilities. The base also supports the Department of Homeland Security in U.S. migrant operations to help care for displaced migrants from the surrounding area, effectively helping control the flow of illegal immigrants into the United States.
The Tampa, Florida office of Orion Marine Construction was contracted by URS Group/RQ Construction to remove an old pier at GTMO and construct a new one in its place. The pier replacement is part of a larger project URS/RQ is performing at the base. To avoid compromising the security of this location, no further details on the scope of the overall project have been authorized by the U.S. Navy.
In October 2014, Accu-Cut Concrete Services, Inc. of Clearwater, Florida, performed cutting techniques with diamond tools to removal the old pier at the base. The work involved flat sawing the main wharf deck, which was cut and removed in sections by crane. The contractor also used a wire saw to cut the main wharf pile caps into sections, making cross sectional cuts through the caps to leave them standing free on the piles. All piles under the caps were cut to different elevations using Accu-Cut’s patented Stingray pile saw. The diamond wire sawing system intergrated into the Stingray, named because of its shape and use in the water, allows it to be positioned around piles and perform clean pull cuts. This custom-engineered saw has previously featured in the Concrete Openings stories Bayway To Go! and Semper Paratus (Always Ready) [December 2013 and 2014 issues respectively]. This phase of work was completed in January 2015 and the new construction began shortly after.
It was six months later, in July 2015, when Accu-Cut was asked to return to GTMO. The construction of the new pier was well under way when the general contractor encountered an issue with several of the pipe piles. After all the new large steel pipe piles had been driven, the concrete caps had been placed and as the deck panels and rebar were being placed, it was discovered that more than ten #11 steel bars would need to be added to six piles to consider each of them structurally stable. The piles already had a cage of #11 rebar and had been filled with concrete to the top, through the pile cap.
Mark Valenti, Professional Engineer and project manager for Orion Marine Construction, contacted Accu-Cut owner John Robinson to discuss several options that would resolve the issue.
“We discussed the possibility of removing all the concrete from the top 15 feet of the pipe piles or core drilling individual holes for each of the #11 bars. Other options were considered, but ultimately the engineers approved a plan to core an 18-inch-diameter hole 7.3 feet deep into each pile. The core was then to be broken off and removed. The inside surface of the hole was roughened before the additional cage of #11 rebar was installed and the opening filled with concrete,” Robinson explained.
Core drilling techniques were specified because it was the least destructive method available for the newly-constructed piles and caps. The low vibration produced by cutting with diamond core bits preserved the integrity of the concrete, while the precision of the cuts provided the general contractor with cores that were easy to remove from the piles.
Once the method was established and the engineering approved, Accu-Cut was given notice to proceed in August 2015 and was instructed to expedite the process wherever possible. The contractor contacted Welco Diamond Tool Corp. to engineer a matched set of 18-inch-diameter core bits 28, 48 and 96 inches long. In turn, the manufacturer reached out to CSDA member Western Saw, Inc., to make the specialty tubes for the bits. Western Saw made the barrels complete with welded tops and 1.25- 7-inch hex nuts ready for Welco to place the diamond segments. The core bits were completed and picked up by the contractor one week after placing the order.
While the core bits were being manufactured, Accu-Cut fabricated a 6-foot aluminum drill column with a removable 4-foot extension. This gave the contractor the ability to have a 10-foot column in case the core drill operator had to back the 8-foot-long bit completely out of the hole while keeping it mounted to the hydraulic spindle. All tools, equipment and spare parts were shipped to site on the GTMO supply barge. This was the only means of shipping available to Accu-Cut for materials, as no commercial courier services deliver to the base. The occurrences of Tropical Storm Erika and Hurricane Fred delayed the arrival of the supply barge by three days, so when the cutting equipment arrived the contractor had to move fast.
An operator began drilling the first 18-inch-diameter hole the day the equipment arrived. The hole was completed and the 7.3-foot-long core removed within five hours. The core weighed approximately 2,000 pounds and was lifted from the opening by crane. The core drill operator then positioned the equipment at the next specified location and repeated the process.
The core drilling was going well for the contractor until the second-to-last hole when, as the bit reached a depth of approximately 4 feet, the stainless steel spindle on the hydraulic core drill machine broke. This was a huge problem, considering there was no commercial shipping to and from GTMO. Fortunately, Robinson found a machine shop on base that was able to repair the spindle—only to have it break again. It was suspected that the 8-foot-long core bit and some possible misalignment issues were the cause. The team from Accu-Cut returned to the company’s shop in Florida, where a replacement drill spindle was fabricated using 4140 alloy steel. The spindle was given to a representative of the general contractor who took the next Navy flight to GTMO out of Jacksonville and delivered the part to the jobsite. An on-site mechanic was able to replace the spindle and two of Orion Marine Construction’s crew members, who had been assisting Accu-Cut with the core drilling operations, were able to complete the last one-and-a-half holes with instruction from Robinson. The crew members also removed a 16-inch-long section of a core that did not break off clean at the bottom of a hole. Several 4-inch-diameter holes were made into the core section using a handheld core drill and 7 feet of extension.
In total, Accu-Cut completed the core drilling of six holes in the pipe piles at the Naval Base. This work created concrete cores that weighed a total of 12,000 pounds. “It is very difficult to work on a Navy base even within the continental U.S.,” said Robinson. “They are very strict on every aspect of safety and planning at all their bases. Add to this the isolation of GTMO and you pretty much only have what you bring for spare parts. We brought every part for our hydraulic core drill machine, all the bearings and seals, all drill carriage parts, rollers gears, bushings and a spare carriage. However, we did not bring a spare spindle and, of course, that was
the part that broke!”
“The Navy requires strict adherence to their EM385 specification and we had to complete Job Safety Analysis and Activity Hazard Analysis forms for every aspect of the operation. This included the setup of the core drilling equipment and the hydraulic power unit, core drilling tasks and the rigging and lifting of the cores. We had to have preparatory meetings with all parties involved—NAVFAC, URS/RQ and Orion—all before any work could begin.”
In spite of the delays encountered during the job, Accu-Cut completed all tasks in a timely manner and to the satisfaction of the general contractor and other authorities involved. The cutting contractor’s successful work on the initial demolition phase of the old pier was the reason why the team was asked to return to resolve the pipe pier issue on the new construction. Between these two GTMO jobs, the concrete cutting company had worked with Orion to remove a pier at another Navy base and so was a natural choice to return and complete these core
“Accu-Cut has a long successful history of performing unique demolition projects for Orion Marine Construction, which in many instances has required Accu-Cut to develop and fabricate specialty equipment to overcome the difficult and unique conditions on respective projects. The cost effective solutions proposed and developed by Accu-Cut have allowed Accu-Cut to meet or exceed our schedule requirements under challenging conditions. Most importantly, the demolition by Accu-Cut has been performed with special attention to overall project site safety, which has been noted by Orion as well as our Clients,” said Valenti.
The time spent at GTMO presented this professional cutting contractor with some unique challenges that were overcome with quick thinking and innovative ideas. By investing time in pre-planning and attention to detail, this CSDA member was able to get the job done.
Accu-Cut Concrete Services, Inc. has been a CSDA member for 14 years and was established in 1990. The company is based in Clearwater, Florida, and services the southeastern U.S. and the Caribbean. Accu-Cut Concrete Services, Inc. has five trucks, nine employees and offers the concrete cutting services of flat sawing, core drilling, wall sawing, wire sawing, hand sawing and grinding. Accu-Cut is a CSDA Certified Operator company.
Orion Marine Construction
Sawing and Drilling Contractor:
Accu-Cut Concrete Services, Inc.
Methods Used: Core Drilling, Wire Sawing, Flat Sawing