J.E. McAmis and National Attachments recently added another chapter to their history of working together. J.E. McAmis is currently engaged in a major job that involves building a jetty on the Columbia River near the Oregon and Washington state lines. The company bought a NYE grapple from National Attachments, which was then mounted onto a Komatsu PC 1100, a huge excavator that weighs 225,000 lbs. (102,058 kg). The grapple, which is 9 ft. tall, opens to 15 ft. (4.6 m) wide, and weighs over 13,000 lbs. (5,896.7 kg), will be used for moving huge boulders in the process of building the jetty.
The full dollar amount of the project is $9.8 million. The scope of the work includes 52,000 tons (47,173.6 t) of placement of stones ranging up to 27 tons (24.5 t) in size. Work encompasses rehabilitation of more than 1,300 LF of jetty and total reconstruction of 200 LF at the end, for a total of 1,500 LF of construction.
According to Scott Vandegrift of J.E. McAmis, the project was originally slated to take two years, and would have concluded in October 2016.
“However, the COE and J.E. McAmis agreed to a fast track approach with a target completion of September 30, 2015,” he said. “Once McAmis and the COE agreed to go for a single season completion, McAmis worked closely with manufacturers and suppliers [including National Attachments] in order to start placing at the end of May 2015. So far, the project is even further ahead of schedule with a targeted completion of September 15, 2015.”
Vandegrift said that McAmis has gone to National Attachments over the years when they had a need for heavy duty attachments or engineering.
“Gabe [Guimond] at National Attachments has been one of the best in the business to deal with as far as his knowledge, quick responses, and assistance when we need something done fast,” he said. “National Attachments will continue to remain at the top of our list when we need specialized large attachments.”
High winds and waves have topped the challenge list so far, according to Vandegrift.
“Though the summer months are generally more calm, we do have our nasty days,” he said. “The area is known as ’The Graveyard of the Pacific’ for a reason.”
The Mouth of the Columbia River (MCR) North Jetty was constructed between 1912 and 1917, with repairs to the segment specific to this contract occurring in 1939 and 1965. An interim repair to an adjacent landward portion was conducted in 2005.
The system consists of three rubble-mound jetties with a total length of 9.7 mi. (15.6 km), constructed on massive tidal shoals and designed to minimize navigation channel maintenance and provide safe transit between the Pacific Ocean and the Columbia River.
The outer portion of the jetty has experienced significant damage from winter storms, resulting not only in loss of jetty length, but also to a narrowing and lowering of the jetty side slopes and crest section starting just offshore and extending to the current end of the jetty.
The jetty repairs are intended to rebuild the jetty cross section to create a more substantial head feature to resist the waves at the outer portion of the jetty, which routinely range from 10 to 20 ft. (3 to 6 m) high. Essential elements of the repair execution include the solid seating of the toe stone, maximized interlocking of the armor stone and tying in the new jetty stone placed with the jetty trunk and the relic stone base.
Repairs involve providing an access ramp from the staging area to the top of the existing jetty crest, constructing and maintaining a haul road from the ramp to the critical repair site, creating a transition area between the existing jetty and the repair site, and repairing the outer end of the jetty. Some haul road construction, including filling large voids, was necessary to gain access to the jetty repair area.
The maximum depth of construction was estimated at about elevation -5 ft. NAVD88, and the crest of the jetty is to be built to an elevation of +25.1 ft. NAVD88 and a width of 30 ft.
Other equipment being used on the job includes a Manitowoc 4600 SIII crane, Cat 988 loaders, Cat 769 haul trucks, Cat 980 loader, Cat D6 dozer, Trimble GPS systems, and assorted support equipment.
Vandegrift said that the North Jetty Critical Repairs project has been a success largely because of relationships built with the Corps of Engineers and critical suppliers and vendors such as National Attachments.
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