Work started in April on the Washington State Department of Transportation’s (WSDOT) project to replace the aging eastbound and westbound bridges of the state Route 6 Rock Creek Bridges (just west of Pe Ell), a $14.5 million project being built by Kent, Wash.,-based Scarsella Bros. Inc.
The reconstruction, funded by a gasoline tax, is expected to be complete in fall 2015. The plan is to replace the existing 90-year-old bridges with wider, more modern structures to help improve traffic flow on this key connection between Interstate 5 and coastal communities. The new bridges will be built to current seismic and flood standards, and with two lanes on span, improve the flow of traffic. The existing bridges are two-lane, but there are almost not shoulders and the lanes are narrow. The new bridges also will be two-lane, but the lanes and shoulders will be wider.
Crews also will reconstruct the nearby intersection of SR 6 and McCormick Creek Road to help improve sight distance and safety for drivers turning onto the highway.
Scarsella Bros. is working on both bridges simultaneously.
“Crews at the east bridge will build a temporary detour bridge so they can demolish the existing bridge and build a new one in the same spot,” said Abbi Russell, WSDOT Communications, “and crews working on the west bridge will shift traffic slightly to the south to provide space to work on a new bridge right alongside the existing one. The two-lane alternate routes are expected to be complete and traffic shifted over this summer.”
According to Colin Newell, the WSDOT project engineer, the west bridge is structurally deficient and the east bridge is functionally obsolete.
“Both bridges were completed in 1924, and they just don’t meet the needs of today’s traffic,” said Russell. “We have a lot of semi-trucks carrying wood products —logs and chips — that travel SR 6, and traffic often has to stop before crossing because the bridges are so narrow.”
The planning process to replace the bridges took five years, with the project definition approved in February 2009 and construction starting in March this year.
“Functional obsolescence is assessed by comparing the existing configuration of each bridge to current standards and demands,” said Newell. “A bridge can be categorized functionally obsolete a number of ways like having substandard lane widths, or narrow shoulders. Another example would be a bridge that doesn’t have enough vertical clearance for large trucks to pass under, causing repeat hits and damage to the bridge.”
The bridges, which were designed in-house by WSDOT engineers, are expected to handle an average of 1,500 vehicles and trucks daily and have a lifespan of approximately 75 years.
“These bridges were designed using WSDOT’s standards for cast-in-place and precast concrete,” said Newell. “These are relatively simple bridges with spread footings, no piers. It’s an economical design that meets the needs of this highway.”
The new bridges are being built to current seismic and flood standards — the current editions of AASHTO LRDF Bridge Design Specifications, AASHTO Guide Specifications for LRFD Seismic Bridge Design, and the WSDOT Bridge Design Manual.
“Flooding in this area is a serious consideration,” said Newell. “We’ve had two 100-year floods since 2007. The bridges were built with considerations for 100-year floods. As far as seismic, we currently design all our bridges to withstand a 1,000-year seismic event.
The concerns and experiences of construction companies and general contractors have been taken into account in WSDOT standards for bridge design.
“These bridges were designed following WSDOT’s general accelerated bridge design construction techniques using prestressed concrete,” said Newell, “which also help to minimize construction time.”
“For this project WSDOT did not solicit contractor feedback on the design except through the WSDOT/AGC monthly meeting where some of the potential contractors looked at the project,” said Newell. “No input was received from the WSDOT/AGC group because these are conventionally designed bridges.”
But Newell pointed out that dialogue with industry stakeholders has resulted in positive changes to construction techniques for bridges, and WSDOT, said Russell “has a program called the Cost Reduction Incentive Program to encourage contractors to partner with us in using ingenuity to save funds and build projects more efficiently. If we accept a contractor’s idea, we share the cost savings with them 50/50 and they assume the risk since it’s their design.”
The new bridges will be straight and have two 12 ft. (3.7 m) lanes and 6 ft. (1.8 m) shoulders, according to Scarsella Project Manager Tom Kress. The west bridge will be about 220 ft. (67 m) in terms of length, while the east bridge will 150 ft. (45.7 m) long.
“In the ordinary high water area,” says Kress, “you can only work in those areas between July and September. We are going to work on both bridges at the same time. The new alignment on the west bridge allows you to build the new bridge before you have to demolish the old and for the east bridge, we are putting up a temporary concrete bridge so that we can tear down the old one and build the new one on the same alignment.”
The temporary bridge, which is being built by SB Structures, consists of the three parts that will be bolted together. It will be retained by Scarsella Bros. to use for other bridge projects. The bridge should be installed in time to maximize work in the creek area. A 180-ton (163 t) crane is expected to be employed to install the bridge.
“It won’t take too much to get the footing pored in for the new bridge and set it and get out before our window is up,” says Kress. “Then we can install deck and infrastructure no matter what time of year.”
To minimize the environmental impact on the creek during the construction, the water will temporarily be channeled into a pipe to keep it flowing. The creek’s channel will undergo a slight realignment so that the new bridges can be better lined up.
The material from the old bridges, which is expected to consist of 1,200 cu. yd. (917 cu m) of concrete and 100,000 lbs. (45,359 kg) of steel, will be recycled.
The new bridges, concrete girder bridges, will have a concrete road surface.
Kress does not anticipate any construction challenges, save for getting the temporary east bridge up rapidly and eliminating traffic issues and demolishing the east bridge and putting in the new east bridge foundations before the water returns. The concrete for the new bridges will be pored in place.
When completed, the new bridges will likely require the use of 1,800 cu. yd. (1,376 cu km) of concrete, 124,000 lbs. (56,245 kg) of steel, and 1732 linear ft. (528 m) of pre-stressed girders, according to Kress.
Scarsella Bros. is bringing in several subcontractors, including Lakeside Industries for paving, Hicks Stripping for stripping, SB Structures for bridge work, Scheffler NW for soil nail wall, C&R Tractor for landscaping, Pacific Rim for guardrail, BC Traffic for traffic control and others for various items.
While this is a small project, Kress and Scarsella use such opportunities to improve the skills of their workers and look for ways to improve efficiency.
“We utilize the unions apprenticeship programs to acquire trainees and then put them with the journeymen to learn the skills needed to perform the tasks needed,” said Kress. “We also try to keep up with the new technologies and tools to allow us to stay competitive in the industry.”
Scarsella Bros. owns a sizeable fleet of vehicles and equipment. No special equipment is being brought in or rented for this project, but due to working in an environmentally sensitive area, biodegradable oil is being used “in case of a leak or something of that nature,” said Kress.
Currently Kress has about 10 pieces of equipment on site — excavators, dozers, loaders, sweepers, blades and trucks. When the work intensifies, this will likely double or triple, with more trucks, equipment and support gear being brought on site.
The increase in equipment will see the number of workers on site rise from around 10 to between 20 and 30 at various times. So far Kress is operating the site on five to eight hour shifts, but when operations begin in the creek, he may increase it to six to 10 hour shifts or longer.
Kress also stressed the need to keep subcontractors updated on the progress of the work so that all efforts can be efficiently coordinated.
“We do a three-week look ahead schedule and make sure that the subcontractors receive a copy so they know what is coming up,” he said.
Scarsella Bros. purchases much of its equipment from various local dealers.
“When deciding on new equipment, Scarsella assesses the need for it, the potential life of the equipment and our previous experiences with similar gear,” said company Vice President Don Scarsella. “Locally, we work with Modern Machinery, NC Machinery — who is our local Caterpillar dealer, and Pape Machinery who is the local John Deere dealer. Our relationships with these dealerships and their parts and service department are extremely important to our business.
“Scarsella also maintains a large Mack truck fleet, so a good relationship with our local Mack dealer is important as well,” he added. “Scarsella sometimes buys new equipment through local dealerships and sometimes buys used equipment through auctioneers such as Richey Bros., or Iron Planet, just to name a few. There isn’t a magic formula that we use for keeping or selling a piece of equipment; equipment buying, selling and trading are usually based on need.”
So far there are no plans to have an onsite mechanic as there are three onsite mechanics at the Mellon Street project who can be brought in when needed. A service oiler visits the work site daily and reports from daily operator inspections are sent to the equipment management personnel to help determine potential problems and better schedule routine maintenance.
The site provides ample space for temporary offices, materials storage and equipment, and that vehicles and equipment are usually repaired where they are parked.
Scarsella equipment and vehicles are inspected before dispatch to projects and again when they come back into to the shop.
“Operators and drivers communicate with onsite mechanics and oilers to communicate potential problems and maintenance needs as well,” said Scarsella. “Most of our machinery is on a service schedule, and as for our truck fleet, drivers fill out a daily report at the beginning and end of their shift noting any necessary maintenance. Since our fleet is used so much on highway hauling, it is imperative that we keep all safety regulations up-to-date in order to ensure the safety of roadways that Scarsella is hauling on.”
Kress pointed out that the existing Rock Creek bridges are solidly built and that he is impressed by the work that was done.
“If you’ve seen any of the older bridges from that time,” he said, “they were real craftsmen and were more like artists then builders. The detail was a lot better — now they just make everything look smooth and utilitarian. The bridges were well built for the time and would probably make it another 90 years if they were not so narrow.”
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