The new Peter Courtney Minto Island Bridge is a steel arch bridge spanning the Willamette Slough, connecting the downtown Riverfront Park to the park on Minto-Brown Island. The new bridge provides access to over 1,300 acres of parks on both sides of the Willamette River for the community while, also linking more than 30 miles of off-street trails. 
The main span of the bridge is a 304.5-foot tied-arch span with four total approach spans, three at 50 feet and one at 35 feet. Combined, the bridge is a five-span bridge, totaling 489.5 feet long. The deck consists of cast-in-place components as well as precast panels for the main span. The supports are made of cast-in-place tapered columns that used a form liner for aesthetics. 
The foundation for the bridge consists of a combination of driven pile and drilled shafts. There are 12 driven piles for the end bent; eight for the Observation Platform and four for the East Approach. The Observation Platform piles were PP 12.75 x 0.500 x 35-feet in length, closed ended, and the East Approach piles were PP 12.75 x 0.375 x 40-feet in length, open ended. The Observation Platform piles were driven to 350 kips and the East Approach pile were driven to 134 kips. There are six drilled shafts for Bents 1-6. 
Legacy Contracting, Inc. was required to install a temporary work bridge as well as temporary support towers that supported the arches in place prior to installing the precast concrete panels. The temporary work bridge consisted of 46 driven piles and the temporary support towers consisted of 12 driven piles, all of which had to be removed once the construction of the bridge was complete. The work bridge piles were PP 22 x 0.375 x 60 feet in length, open ended, and the support tower pile were PP 18 x 0.500 x 100 feet in length, open ended. The work bridge piles were driven to 518K kips and the support towers piles were driven to 395K kips.
For the cast-in-place deck portions of the bridge, Legacy Contracting also drove piling for the falsework. Sixty 12-foot wood piles, two 22 x 0.375-foot and six 18 x 0.500-foot piles were driven for the falsework. Legacy Contracting had to pull all the steel piling as well as the wood piling they could reach after concrete was poured. 
All of this work was completed in an environmentally sensitive area and done during stringent in-water work timeframes. The existing material that the piles were driven into had a rock shelf that required Legacy Contracting to drive the piling in a matter that didn't cause the piling to cave in on itself.

Challenges
The Minto Island Bridge is a one-of-a-kind structure from the foundation up. Although there are only 12 permanent piles in the finished product, many more were required in order to build this beautiful bridge. Driving the work bridge, support tower and falsework piling in a very sensitive area and completing the work within the in-water work window was challenging. Legacy Contracting was able to use a vibratory hammer and impact hammer to drive the pile through the difficult subsurface conditions.

Silver Sands State Park is located on the Long Island Sound in Milford, Conn. During low tide, visitors can walk across to Charles Island, famous for being the site where Captain Kidd supposedly buried his treasure after he visited the island in 1699, before traveling to Boston where he was captured and later hanged. The island connects to shore via a tombolo (sand bar) at low tide.
The park is an area of approximately 300 acres of beach, sand dunes, marsh, woods and the 14-acre bird sanctuary of Charles Island. The State of Connecticut acquired Silver Sands after hurricane Diane came through in 1955, destroying 75 homes in the area. Today, the park is used for picnicking, saltwater activities, field sports, nature programs and more. 
Blakeslee Arpaia Chapman, Inc. (BAC) was contracted by the Connecticut State DOT to provide the foundation work for the park's phase 1B improvements. The improvements consisted of the installation of raised, pile supported bathhouse and concession area, several handicap accessible ramps to and from parking areas, boardwalks along the beach and a walkway across wetlands connecting to an existing boardwalk.
Challenges

Wildlife 
The project included many obstacles. The first of which was the sensitivity to the indigenous species and the need to minimize any impact on them. In late March, Connecticut beaches become the nesting ground for piping plovers, a small, sand-colored shorebird. Piping plovers are on both federal and state lists of threatened species. These migratory birds don't make nests, but rather use small depressions in the sand as their place to roost and incubate their eggs. 
In order to minimize any disturbance to the birds, it was determined all pile driving activities within 160 feet of their breeding ground (the beach) needed to be complete before their migration into the area. Approximately half of the 250 piles on the project fell within the buffer zone. Due to delays to the start of the project, BAC was left with just over a week to complete this first phase.

A walkway over the wetlands 
A second challenge in the project was how to install an eight-foot wide timber pile supported walkway through 290 feet of wetlands to meet and attach to another existing walkway. The walkway consisted of two pile bents every 14 feet with a split cap and cross bracing. The specifications precluded any equipment from entering or bearing upon the wetlands.
The solution was to have the pile driver drive the piles from on top of the walkway. The eight-foot walkway was neither wide enough nor sufficient to support the pile driver. To make a safe platform, the following changes were made:
Added temporary piles outside the permanent piles. 
Increased the size of the split cap and extended the split cap out to the added temporary piles.
Increased the size and quantity of the hardware connecting the split cap to piles.
Added longitudinal cross braces to the specified transverse cross braces.
Installed steel beams across pile bents.
Laid crane mats on top of the steel beams.
Installed safety railings for protection of all personnel working the temporary platform.

Since the walkway connected to an existing walkway, the team worked their way out two bents at a time. Once all the piles, caps and braces were in, they backed their way out, removing the temporary piles and cutting the extended split caps back to the eight-foot permanent walkway width.
This was an efficient method and BAC was able to complete the project on time and under budget, despite the numerous challenges encountered.

Corman Kokosing was awarded the Naval Academy Cyber Security Studies Building Concrete Piles contract in Annapolis, Md. The proposed building was constructed on a site that had undergone significant changes. Various bulkheads, building foundations and sea walls were constructed on the site over the years as the site had been expanded. Also, various miscellaneous buildings had been built and demolished at the site. Piles remained buried within the footprint of the proposed building. The land at the site was reclaimed from Dorsey Creek and has since required stabilization.
The overall scope of this project is to deliver the latest addition to the campus of the United States Naval Academy. This $114 million Center was a design-build of a 206,400 sq. ft. academic building dedicated to the education of midshipmen in all areas of cyber warfare and will include classrooms and lecture halls, teaching and research laboratories, a research and testing tank to support the engineering and weapons laboratories, an observatory, offices and multi-purpose collaborative space for students and faculty. Situated between Nimitz Library and Rickover Hall, the Center will be surrounded by elevated hardscape terraces continuous with those of the adjacent buildings.
Corman Kokosing Pile's experience and Atlantic Metrocast's SlickCoat piles process was the perfect combination to provide the pile foundation to build the premier educational and research facilities for the government's unique project. The design began immediately and construction on the Center for Cyber Security Studies began in late 2016 with an anticipated completion in the third quarter of 2019.

Techniques and equipment 
Since the piles needed to be 140 feet long, a mechanical splice (Emeca Splice) was used on all piles. A 200 TN Manitowoc would offload the piles from a barge and feed the 70-foot pile piece into the leads of the pile driving 165 TN Terex, which put the crane booms within a few feet of each other twice for every pile. 

Unique application of piles
Augering and probing was required for the 369 pile locations to locate potential obstructions, and concrete piles were driven (14-in. x 140 LF) with a slick coat application.
Design of the proposed building and foundation was coordinated to allow for continued access to the Nimitz Library foundation system. The contractor evaluated slope stability. Slope stability analysis was performed as part of the geotechnical investigation by the Geotechnical Engineer of record, in accordance with UFC 3-220-01 Geotechnical Engineering and EM 1110-2-1902 Slope Stability. Methods of slope stabilization included land-side solutions only. Loading the site was limited prior to and during construction in order to avoid adversely impacting slope stability. The evaluation and subsequent remediation of the site ensured slope stability prior to construction, during all phases of construction and for the long term following construction.
The pile fabricator's design team indicated that the concurrent tension/bending moment were well outside of what would be considered acceptable for a standard 14-inch concrete pile. It was necessary to maintain 14-inch concrete piles throughout the site so a superior concrete pile was engineered that would be able to withstand the stresses during driving. The information used was based on the provided:
Axial Compression 180 Tons (522 kips)
Axial Tension 40 Tons (128 kips)
Bending Moment 120 ft-kips

Construction problems and creative solutions
The site location was in proximity to the U.S. Naval Academy's Nimitz Library and Rickover Hall. Limited space in and around the project site required the piling delivery be supported by the marine group's tugs and barges, which required installing spud wells to protect the Naval Academy waterfront promenade.
The presence of bulkheads, seawall, piles, slope instability and miscellaneous buildings previously constructed at the site impacted the construction of the foundations. Available historical design documents from past construction projects did not accurately show actual conditions. The team prepared for many types of buried obstructions to be excavated and removed to make way for new construction work.
Alternatively, it was permissible to locate deep foundations to clear existing obstructions and construct bridging over the obstructions. This alternative complicated the foundation construction, but permitted some obstructions to be left in place.
Also, the piles had to be driven in a specific order so cranes could crawl out without interference.

Cost saving measures
Due to the extreme length of pile required, value engineering was used to incorporate the Emeca splice, which encouraged the use of concrete piles as a cost saving measure to the owner. 

Innovative project management
The piles were coated offsite to reduce down drag with Slickcoat, which allowed for a faster coating due to the limited space onsite. The piles were all loaded onto barges already coated and ready for use. Corman Kokosing chose to use a hydraulic hammer rather than a diesel hammer due to the close proximity of subcontractors. A special tray that the power pack could sit on attached to the crane and took the place of counter weights was fabricated. This kept the hydraulic hoses close to the rig and away from potential hazards.

Design changes 
Corman Kokosing deep foundations included provisions for locating equipment in areas that remained underwater. Buildings adjacent to the proposed site conduct research using equipment sensitive to vibrations. Vibration monitoring and coordination of work restrictions was paramount during foundation construction activities.

Management or mitigation of environmental considerations
The upper strata soils at the site (approximately 100 feet thick) were fairly weak and prone to settlement. A deep foundation system extending in excess of approximately 120 to 150 feet was required to support the building structure. The soil at the site was not suitable to support a slab-on-grade.
Noise and ground vibrations caused by construction equipment was monitored. All work met required compliance with Anne Arundel County noise ordinance and ground vibrations did not exceed the project's established threshold value.
Corman Kokosing Construction is proud to have been a part of this project.