- Company: Rummel Construction
- Industry: Transportation
- Location: Sedona, Arizona
- Expected Completion Date: August 4, 2015
- Project Website
For years, changes in stream flow threatened a section of roadway on State Route 89A near milepost 385 that showed signs of the embankment sliding and erosion into the creek. The existing gabion baskets that anchored the toe of the slope were bulging into the creek. A significant rise in creek level from upstream runoff could have washed out the highway. To remedy this problem, ADOT considered and evaluated numerous design alternatives. The initial plan for this bank protection was to relocate/divert the stream, dry the embankment area up and complete the construction. The bank protection solution was designed but held up for several years due to the environmental clearances.
In 2014 the bank protection project was revitalized and new issues were accounted for. New issues included obtaining environmental clearances, constructability issues and the newly named endangered species, the Narrow-Headed Garter Snake which was living in the existing gabion baskets. The flowing Oak Creek (a designated Outstanding Arizona Water), the Narrow-Headed Garter Snake and the Mexican Spotted Owl could not be impacted. The initial plan would no longer work and construction would need to occur with the stream running below increasing construction difficulty. The AZ Game and Fish, Coconino National Forest, ADOT and local environmental activists all had their eyes on this small but critical project.
OUTCOME
The team safely constructed a quality project with no environmental impacts AHEAD OF SCHEDULE.
PROJECT SUCCESSES
• Overcame working in a very tight, congested workspace on a hairpin turn where there was no right-of-way and had heavy recreation traffic counts
• Successfully used partnering to overcome challenges
• Adhered to strict environmental requirements with no impacts
• Devised innovative construction methods that increased production
• Maximized the project footprint allowing for different construction methods to be used accelerating the schedule
• Worked Safely – Zero accidents
• Completed one month early reducing the impact to the traveling public and nearby residents
What impact does this project have on America?
Oak Creek Canyon is one of the crown jewels of Arizona’s outdoor recreation areas; the scenic beauty attracts thousands of visitors year round. It is known as the Grand Canyon’s smaller cousin and is the second most visited recreation area in Arizona. State Route 89A is a vital connection between the cities of Flagstaff and Sedona transporting visitors along the canyon for 13 miles with a series of hairpin turns. The route is also vital to the local economy as many local businesses rely on tourism. This construction project protects the highway and keeps rural Arizona pristine.
The successful completion of this project left the community with a beautiful vantage point and many project accomplishments.
• Maintained two lanes of traffic
• Maintained commute times for Sedona residents
• No traffic complaints were logged
• No environmental impacts
• Added safety measure to final project for the visitors who will be up and down the banks of the creek
• Quality project to withstand extreme creek flow while protecting highway embankment
• Finished one month early!
What interesting obstacles or unusual circumstances did you overcome to complete the project?
The environmental sensitivity, restricted project access and difficult work sequence necessitated that a step-by-step work plan be developed by Rummel’s project management team. This sequence was presented to stakeholders in a meeting for input and suggestions prior to starting the work. Although not required this was determined to be the best way to inform partners of the plan and gain acceptance and cooperation moving forward. Transparency and willingness to accept stakeholder concerns and incorporate them into the process is a keystone of a successful project. This allowed stakeholders to understand the challenges of the project and allowed cooperation for us all to achieve the partnering goals through collaboration and a shared vision.
What dangers and risks did you encounter, and describe any extraordinary methods used to keep workers safe?
Additional steps taken during construction provided safety for the workers and the traveling public. Rummel Construction is proud of our safety record, our EMOD is .49!
The project had limited work areas and restricted access for parking and equipment. A steep 2:1 slope behind the guardrail with a flowing creek below and steady flow of sightseers and commuters from Flagstaff required additional planning.
ADOT required two lanes of traffic to be maintained to keep traffic flowing without interruption, Rummel produced a concept to widen the shoulder with temporary paving to hold traffic. This widened the construction area footprint allowing for alternate construction methods allowing the team to accelerate construction and finish early.
Although traffic increased as the weather warmed, no traffic complaints were logged. A key to no complaints was a designated supervisor at the road level who coordinated flaggers minimizing stoppages in traffic. The team also maintained communication with Forest Service and Parks on either side helped them inform visitors of construction activities.
How did you leverage new technologies to work faster and reduce waste?
Equipment Modification – The design called for installation of 60 feet of rail bank protection requiring 17.5 foot lengths track rails (like a rail road track) to be hydraulically hammered into the embankment near the stream at an angle. The typical construction method for rail bank protection installation would use a large excavator or a crane equipped with a 25,000 lb vibratory hammer attachment. The inward angle would not be able to be reached with an excavator from the top and there was not room for a landing pad to accommodate the equipment near the stream. Nor was it acceptable to place the equipment in the creek. To overcome this challenge Rummel’s Equipment Shop fabricated an attachment that allowed the hydraulic hammer to work at various angles and created a sleeve to fit over the rail so they could be hammered into the slope at an inward angle into the bank which could not have been accomplished with a traditional pile driver. This improved the ease of construction and safety while eliminating one month of vehicle emissions.
Redesigned Gabion Baskets in the Field – The designers had limited information and a tight schedule so ADOT could bring a contractor on board and complete the project prior to the next monsoon season. The embankment continued to erode after the design of the gabion baskets. Rummel surveyed the slope and partnered on field modifications to adjust to the existing conditions so it would be flush with the roadway.