Turning the Tide
Diamond Tools Strengthen Pier’s Tidal Defense
(Photo Courtesy of Gary Pescod)
A specialist contractor recently drilled over 1,400 holes and played an integral role in the £3.4-million (approximately $5.4 million) restoration of a 100-year-old pier on the northeast coast of England. Without this restoration, a nearby harbor and town were at an increased risk of flooding and coastal erosion.
The Craghead, County Durham, office of D-Drill Master Drillers Ltd., a CSDA member based in Coventry, United Kingdom, performed diamond core drilling tasks at Seaham North Pier as
part of a two-year refurbishment project. The aim of the project, due for completion in November 2015, is to protect the town and harbor from potential flood situations and minimize erosion caused by the North Sea tides.
Seaham Harbor is protected by two outer piers, the North Pier and South Pier, which were built in phases between 1899 and 1906. The North Pier is next to Seaham North Dock, which was recently refurbished for use as a marina. To the south of this is the larger South Dock, which is a commercial port. Due to its poor condition and its greater importance and function in protecting both the harbor and Seaham, the North Pier was identified as being in need of restoration. The structure was at risk of partial failure during storms and without improvement, it will continue to decline over the coming decades. The restored pier will protect over 100 residential properties, more than 30 commercial properties and Seaham Harbor, a marina development that supports the local economy and regeneration initiatives in Durham County.
The U.K. Environment Agency and Durham County Council, the Lead Local Flood Authority responsible for flood prevention and coastal protection have jointly funded the pier refurbishment, and appointed Carillion plc of Wolverhampton as Principal Contractor for the works. The pier is owned by Victoria Group, the port operator. Restoration work began in July 2014 and D-Drill was contracted to start its tasks the following month. The first phase of the company’s work lasted four months. D-Drill used specialized diamond drilling and sawing equipment for the cutting tasks. This included the use of a Husqvarna FS6600D slab saw to make cut lines 300 millimeters deep (12 inches) along the inner edges of the pier’s coping stones to allow the center deck to be broken out for replacement. These cut lines ran approximately 1,200 millimeters (47 inches) parallel from the edges of the pier and equated to around 1,000 linear meters (3,281 feet) of cutting, completed August to October 2014 and March to June 2015. Operators also made 10 cuts measuring 1,200 millimeters long (47 inches) and 600 millimeters deep (24 inches) across the coping stones to allow damaged sections to be removed and replaced.
Operators then drilled 40-millimeter-diameter (1.6-inch) holes 600 millimeters (24 inches) deep into existing Norwegian granite. This drilling work was through existing holes to increase their depth and create rough, clean edges to accept new rebar and grouting. The overall depth of the holes was approximately 1,200 millimeters (47 inches). It took an average of 20 minutes to drill each hole to its required depth, which included time for the setup and moving of equipment, and two operators made an average 30 holes each eight-hour shift. In addition, 20 32-millimeter-diameter (1.3-inch) holes were drilled 300 millimeters (12 inches) deep into the side of the copings for starter bars over which the new top slab would be cast.
All sawing and drilling tasks were completed within the fourmonth time frame, then D-Drill returned to Seaham’s North Pier several months later in March 2015 to complete further tasks and ensure the project could finish on schedule.
“The Seaham tidal defense project was an intricate job in testing conditions. As well as securing our engineers to a safety line, we had to bolt a safety stop to the coping to eliminate the risk of the diesel saw going over the edge into the sea!” explained John Emberson, D-Drill’s northeast branch manager.
D-Drill used toolbox talks, written method statements and risk assessments to avoid accidents and injuries on the jobsite. Tidal conditions and inclement weather situations were discussed, so the sawing and drilling team knew that there would have to be some flexibility with work hours to complete the job on time. Once on the jobsite, operators were supplied with safety harnesses and attached to a safety line. Meanwhile, a safety boat was in the water every shift and a safety lookout person was present on the pier at all times during the work.
In total, the contractor completed approximately 2,000 meters (6,562 feet) of slab sawing and drilled over 1,400 holes ranging from 25 millimeters (1 inch) to 40 millimeters (1.6 inches) in diameter to depths of up to 600 millimeters (24 inches) for new rebar. A further 650 holes were made 12 millimeters in diameter (0.5 inch) and 50 millimeters deep (2 inches) for the installation of new hand rails. The job was completed on time and within budget.
The overall Seaham North Pier refurbishment project remains on schedule for a November 2015 completion. Thanks to the speed and precision of this CSDA member’s work, the pier will continue to act as a strong tidal defense for the surrounding harbor and town.
“We are proud to have worked on such an important project for the area. It was absolutely vital that these sea defenses were shored up,” said Emberson. “Everything we did on the job was limited by the incoming tide and weather so we had to plan our work accordingly. To that end, we had to pay very strong attention to health and safety—including securing our employees to safety lines running the full length of the pier,” he concluded.
D-Drill Master Drillers Ltd. has been a member of CSDA for 33 years and has been in business since 1967. Based in Coventry, England, the company has 94 employees and 70 trucks in 10 locations across the country. D-Drill offers services that include core drilling, slab sawing, wall sawing, hand sawing, wire sawing, controlled demolition, diamond floor grinding and floor preparation services.
Sawing and Drilling Contractor:
D-Drill Master Drillers Ltd.
Coventry, United Kingdom
Phone: 44-1752 341364
Methods Used: Slab Sawing, Core Drilling