02/05/2011 - 04:00 am

SC&RA Details Top Rigging Jobs

The Specialized Carriers & Rigging Association (SC&RA) has announced awards for Rigging Job of the Year. The awards went to Fagioli, Manvel, Texas, in the Jobs over $750,000 category and Barnhart Crane & Rigging, Memphis, Tenn., for both the Jobs between $150,000 and $750,000 category and the Jobs under $150,000 category. Issued by SC&RA, details of the winning projects follow.

Jobs over $750,000

Fagioli removed and replaced two stators at the Laguna Verde Nuclear Power Plant in Veracruz, Mexico. Laguna Verde is the country’s largest electric power generating nuclear plant, producing about 4.5 percent of the nation’s electrical energy. To increase the capacity of the plant by 20 percent, two stators needed to be replaced. There were many challenges to the job including the heavy weight of the stators (720,000 pounds each); restricted working area; insufficient capacity of the existing overhead crane; and unavailability of time to test the fitting of the system.

Fagioli’s engineering division came up with a solution to complete the operation without the need for civil interventions within the operative plant. Engineering preparations started a year and a half before the job began. Due to the insufficient capacity of the hook on the overhead crane, Fagioli designed a lifting system consisting of two L300 strand jacks, which was conceived to fit between the existing beams of the overhead crane. After being awarded the job in August 2009, Fagioli required several months of intensive work to complete the design. The final approval was given in December 2009, leaving only two months to fabricate, test and ship the system to the jobsite. Fabrication was done in Houston with Fagioli engineers monitoring the quality and testing the components before delivery in mid-February 2010.

The lifting system itself weighed almost 133,000 pounds and was built with high-grade steel to keep the weight within the limit indicated by the overhead crane manufacturer. The system consisted of a swivel connected to the anchors of the strand jacks. The 300-ton strand jacks were positioned on the jack support beam, which sat on each end on a U-shaped structure. The 882,000-pound capacity swivel rollers and girders were supported by the beams of the existing overhead crane. The structure was suspended from the traverse top beams, and at both ends the roller beams sat on the overhead crane girders, precisely on the trolley tracks.

When the installation work of the system started inside the building, 24-hour continuous operations were necessary due to the 45-day window allotted. Every effort was made to maintain exposure to radiation far below the dose limits as practical. This included wearing protective clothing, continuously monitoring radiation absorption of each person, having back-up crews, and shifting personnel.

All operations for the removal of each generator, including installation and removal of the lifting system on and from the overhead crane, were to take place within 84 hours. The same timeframe was allotted for the installation of the new generators.

With the limitation of 12 feet per hour on the 200-foot translation of the overhead crane between the equipment hatch and the generator foundation, the time left to install and remove the system, lift the generator 15 meters, rotate it 90 degrees and lower it 5 meters, was minimal. Fagioli accomplished the task a day ahead of schedule without accidents.

Jobs between $150,000 and $750,000

Barnhart erected 11 prefabricated sections into one 420,000-pound final cofferdam for a San Diego Water Authority project. The San Vicente Dam was raised 100 feet to provide more water to the San Diego region. Phase I of the project was to prepare the dam for the concrete work, which involved the widening and raising of the dam structure. A cofferdam was needed so that a new discharge tunnel could be drilled through the dam structure. After erecting the prefabricated sections, Barnhart had to lower the final cofferdam into the water and onto the dam wall at approximately a six-degree angle, and to hold the load in a stationary position to allow divers to secure the cofferdam to the face of the dam, which was estimated to take five to 10 days.

Due to a lack of other feasible options, Barnhart developed the lifting system on top of the dam. Still, there were challenges to installing such a system. Access was difficult, the work area was tight, and the weather was windy and hot. Barnhart engineered a cantilever system on top of the water dam to perform multiple lifts of cofferdam sections using strand jacks. The cantilever system consisted of sixty 130-foot strands, two 300-ton strand jacks, three 450-ton strand jacks and five floating anchors.

A total of six cofferdam lifts were performed with the largest piece weighing 410,000 pounds. The job was challenging due to the incline and the fact that multiple jobs were going on within the vicinity of Barnhart’s equipment and work area. Barnhart’s cantilever system included a synchronized strand jack system, elimination of counterweights with an anchor design, rocker design and installation, the use of an erection sequence/straddle barge, and the tilting of the cofferdam to the slope of the dam face.

The cantilever system required just five truckloads of rigging equipment. Barnhart supplied engineering, project management, risk management, superintendent, and strand jack technicians. The customer supplied the lift crane, craft labor, barges, and water bags for the test lifts. Barnhart’s safety program included highly trained crews with QUAL cards, daily safety meetings, communications plans, pre-lift meetings, PPE and fall protection, an onsite risk manager, and a test lift. The job was completed safely in 30 days with no issues or violations.

Jobs under $150,000

Also taking the under-$150,000 category, Barnhart removed two vessels from an existing structure and replaced with new vessels during a refinery turnaround in southern California. The first vessel weighed 14,310 pounds, measured 4’6” in diameter, and was 16 feet long. The second vessel weighed 29,349 pounds, and was 8 feet in diameter and 20 feet long.

The challenge was removing the two horizontal vessels from the existing structure without removing a substantial portion of the structure. There was also very limited access to the worksite, and work had to be done over and around active process piping and equipment. The engineering team ruled out using a crane to remove the vessels through the roof of the building or using two cranes to insert the vessels into the building.

The solution was a tri-block and cantilever beam system in which counterweights were used to counter-balance the payload to allow the lifted item to be lifted under an overhead obstruction. The auxiliary load line was then operated to adjust the pick point and set the load in final position.

The plan required lifting and transferring of the vessels over “hot” lines and other operating equipment. A test lift was performed for the refinery personnel to demonstrate this approach. After formulating a complete engineering package that included a Critical Lift Plan, Certificates of Conformance for all rigging equipment certified and stamped by California P.E., Barnhart went ahead with the plan.

A comprehensive safety plan was developed to meet the client’s stringent safety procedures and Barnhart’s corporate safety standards. Crews underwent Los Angeles Refinery Safety Operation training. The Barnhart construction manager conducted task safety meetings, including Job Hazard Analysis, with responsibilities assigned before each stage of the planned work. Due to working at elevations exceeding 6 feet, there was 100-percent tie-off for crewmembers.

The process started with the staging/assembly of equipment, lifting and removal of existing vessels, placement of existing vessels onto a transporter, transport to laydown area, transport of pre-loaded new vessels to the work site, and lifting and setting the new vessels in place. Engineering included crane layout drawings that were reviewed by the client’s civil engineer. It was determined that foundations would have to be installed in the existing roadway to support the outriggers on the crane, which was a Grove Model GMK 6350 supplied by Maxim Crane. Safety was built into the lift plan process, as the crane selected operated at 71 percent of capacity. The crane layout included a detailed plan of how to assemble the crane and the related equipment since space was very tight.

The tri-block and cantilever beam assembly was staged and assembled in a blocked-off road parallel to the structure housing the vessels. Prior to the lifts crews checked all equipment and reviewed communication protocols. The lift director flagged the crane during the entire lift process. All operators had QUAL cards. Before each lift the crews reviewed contingency plan/shutdown sequences with the client’s operators. The first vessel was removed and replaced in one day and the second vessel was removed and replaced in one day. The project was finished two days ahead of schedule without any accidents.

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