This is equivalent to $320-$395 per square yard. This option would provide the longest lasting roadway of all the option
Evergreen Corridor Pavement Plan Southeast Chelsea Avenue to Southeast 164th Avenue City of Vancouver, Washington May 2017 INTRODUCTION This report presents the City of Vancouver’s (City) pavement plan for the Southeast Evergreen Highway Corridor, a 20-foot-wide, Portland cement concrete (PCC) roadway that was constructed in 1919 and 1920. The first paved roadway in Clark County, it was built to the standards at the time with concrete panels and no shoulders. The roadway was experiencing deteriorating conditions even before being annexed by the City in 1997. Asphalt overlay was applied in many areas to help improve the driving surface, but over time and with increased traffic, that became rough and uneven. The extensive cracking and deterioration result in very rough riding conditions for bicycles and vehicles. The pavement has been further impacted by water infiltration through the severe cracking, affecting the subgrade and causing freeze/thaw damage during winter. As noted in the Evergreen Corridor Management Strategy, “One of the top priorities for residents is to see the roadway improved to create a smoother riding surface and ensure maintenance is provided on a reasonable cycle.” This report sets forth the plan for addressing pavement along the section of the corridor that is approximately 5 miles long, extending from Southeast Chelsea Avenue east to Southeast 164th Avenue, as shown on the attached Evergreen Corridor Pavement Management Plan Map. The corridor section Southeast 164th Avenue to the city limits, not part of this report, will be addressed after the section from Southeast Chelsea Avenue to Southeast 164th Avenue has been resurfaced.
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EVALUATION In recent years, the City has evaluated the corridor through engineering studies, pilot projects, and street maintenance efforts. Engineering Studies In 2016, the City contracted with GRI to perform a pavement evaluation of the corridor to analyze the existing PCC roadway and provide recommendations for resurfacing the corridor. The results of their evaluation are presented in their report dated Aug. 12, 2016. The following is a list of their primary findings. o The existing concrete slab is about 5 to 7 inches thick (6.5 inches on average) and lies directly on silty sand. o There is good joint transfer between slabs. This will help slow down reflective cracking of an asphalt overlay above the joints between slabs. o There was no rebar encountered in the slab in the core holes. However, rebar has been encountered in the slab by City Public Works maintenance crews at the Mill Creek Culvert crossing near Southeast 101st Avenue and during other utility work near Southeast 164th Avenue. o GRI recommends reconstruction of the PCC roadway if funds are available. Less preferred alternatives are a 3-inch overlay, or microsurfacing. The City retained consultant Otak Inc. to prepare planning-level cost estimates of four corridor replacement options that involved removing the existing concrete and then paving. Replacement options included full-depth hot mixed asphalt (HMA); a crack-and-seat process with HMA overlay; pervious concrete; and full-depth Portland Cement Concrete Pavement (PCCP). Of these options, Otak recommended removing the existing concrete and paving as the most reasonable approach. Construction costs for this option ranged from $18.6-$23.1 million, which equates to about $320-$395 per square yard. Otak’s results are presented in their Technical Memorandum dated March 7, 2016. DKS Associates performed a study of existing traffic conditions along the corridor for the City. Those results are presented in their memorandum titled, “Evergreen Corridor Plan Transportation Technical Memo”, Jan. 22, 2016. The main finding substantiates that most traffic flow occurs between Southeast 164th Avenue and Ellsworth Road, and that there is less traffic west of Ellsworth. In addition, most of the traffic is from passenger vehicles, with 2
minimal local delivery trucks. Other findings in the memorandum pertain to traffic calming plans and did not have bearing on pavement planning. Pilot Projects The City conducted two pilot projects, the first in 2014 and the second in 2016, to help evaluate pavement options of the corridor. The locations of the two pilot projects are show on Figure 1. 2014 Pilot Project The 2014 Pilot Project consisted of an enhanced cape seal about 3,000 feet long and extended from approximately Southeast Bella Vista Place to Southeast Rivercrest Avenue. The enhanced cape seal consisted of a two layers of microsurfacing with a layer of asphalt rubberized chip seal sandwiched between the two microsurface layers. Minimal surface preparation, consisting only of removal of thin delaminated asphalt patches, was performed before placing the enhanced cape seal in the pilot project area. An enhanced cape seal is different than an HMA pavement. Generally, an enhanced cape seal will help make a street smoother, but not as smooth as an HMA pavement. It is also grittier and initially softer than an HMA pavement, but it can be very cost effective depending on the street condition and location. Its main purpose includes improving smoothness, sealing micro-cracks, and protecting existing pavement from environmental factors such as sun and rain. It is also thinner than an HMA pavement. It’s important to note that the enhanced cape seal in the City’s 2014 Pilot Project was only about 3/4 inches thick, which makes it susceptible to reflective cracking. At this thickness, most of the cracks in the PCC roadway will reflect up to the surface within a couple years. Overall, the enhanced cape seal has performed well and as anticipated. One of the main pavement performance measures observed is how well it would adhere to the PCC roadway. To date, the enhanced cape seal has adhered to the PCC roadway with no observable delaminations. Another performance measure is the reflective cracking. As mentioned, the reflective cracks from the PCC roadway surface have quickly appeared at the surface, as expected. The cracks are narrow and typically about ¼ inches wide. At this width they present no pavement performance concerns. If cracks widen, the City will evaluate the need to crack seal them to help protect the pavement from water intrusion, which could lead to 3
delamination. Pavement conditions are measured by an industry accepted standard of indexing. The PCI (Pavement Condition Index) scores range from 0 to 100 with 100 hundred being the best. PCI scores along this section of road currently average 78. Before the pilot project, its average PCI was 53. The unit cost of the enhanced cape seal was about $13 per square yard. However, based on discussion with the local neighborhood association leaders, the ride quality is still rough and does not meet their expectations. Advance surface preparation, which would cost an additional $5 to $7 per square yard, including crack filling, milling, and pavement repairs would help improve the riding conditions. 2016 Pilot Project The 2016 Pilot Project consisted of an HMA mill-and-overlay paving from Southeast Image Road to Southeast 98th Avenue. The 2016 Pilot Project was approximately 1,500 feet long and was constructed as follows:
Highly distressed areas of the PCC roadway were repaired by cutting and removing failed surface areas. These were then backfilled with compacted HMA.
Cracks wider than ½ inch were filled with an emulsified asphalt sand slurry.
The existing PCC pavement was milled 2 inches at the edge and transitioned to no milling at centerline. The purpose of the milling was to help smooth out the rough surface and make the new HMA tie in evenly with adjacent at-grade concrete driveways.
The surface of the roadway was then overlaid with 2 to 3 inches of HMA. The HMA was thinner at the edges and thicker at centerline.
The westbound lane incorporated a fiber glass paving grid to slow down the migration of reflective cracks from the underlying PCC roadway.
The 2016 Pilot Project is performing well and shows no pavement distress. However, it will be several years before the results can be better evaluated. The City anticipates that reflective cracks could start to reappear in about 4 to 6 years and should take longer in the west bound lane since it has the paving grid. The total cost to construct the 2016 Pilot Project was $145,000, a unit cost of about $44 per square yard that includes the fiber glass paving grid. Without the paving grid, the cost is $36 per square yard. The City anticipates that the cost of the paving grid will be even greater in the future due to the challenges experienced by the contractor of installing the glass grid in a confined environment.
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Street Maintenance The City has considerable experience with maintenance paving along the corridor. In 2006, several thin pavement patches were placed in areas with high severity cracking along the corridor. The patches were generally less than 1.5 inches thick and found to quickly delaminate. Some delamination began within one year of placement. The following year, in 2007, the City increased the thickness of the HMA with a pavement patch near the Fish Hatchery at Columbia Springs Environmental Education Center, as shown on Figure 1. This time the HMA layer ranged from 2.5 to 4 inches thick. The PCC roadway in this area had high severity cracking, and no concrete repairs were made before paving. This pavement patch has performed well and has minimal deterioration. In 2015, the City milled out asphalt patches along the corridor. Milling out the asphalt patches helped make the surface smoother and improved the ride quality. In 2016, the City made nine pavement patches in areas with the roughest roadway. The pavement patches ranged from 50 to 1,500 feet in length. The most substantial patches were made near the Fish Hatchery as shown the attachment, SE Evergreen Corridor Pavement Plan Map. These patches consisted of approximately 2.5 to 3.5 inches of HMA asphalt that extended across the full width of the road at most of the locations.
DESIGN AND CONSTRUCTION CONSIDERATIONS Resurfacing the corridor presents several design and construction considerations. The primary considerations are summarized below. Existing Road Surface Condition The existing PCC roadway surface has severe cracking along its entire length. Cracks range from hairline to several inches wide. The roadway has a concrete joint every 30 feet, resulting in a roadway of 20-foot-wide by 30-foot-long, concrete slabs laid end to end. Most of the cracks are at the corners and along the outside edges of the slabs. There are also frequent transverse thermal cracks at the midpoints between the joints. In addition, there are longitudinal cracks that meander near centerline along significant portions of the
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roadway. All the cracks have the potential to reflect up through any new surfacing put on top of the existing PCC roadway. Adjacent Grade Constraints Adjacent driveways and side roads create grade constraints. The surface of the new road will need to match the height of adjoining surfaces for smooth transitions. Two options to make smooth transitions are: (1) mill the existing PCC roadway down so that the new surface will match the existing adjacent surface, or (2) reconstruct part of the existing driveway and side roads to transition into the new roadway elevation. Many adjacent grade constraints consist of concrete, which increases the cost for the second option. Limited Access The corridor has limited access for construction. The only access locations are from the east and west ends of the corridor, Southeast 88th Avenue and Southeast Ellsworth Road. It is City policy to keep a lane of traffic open for traffic in each direction during construction. Because of the limited access and narrow 20-foot-wide roadway, this will not be possible within the Evergreen Corridor so it is likely that roadway construction would require traffic to be reduced to one lane with a pilot car to help guide vehicles through the zone safely. Culvert Crossings There are about 150 culverts along the corridor and about 1/3 of these culverts cross under the PCC roadway. The City is conducting a culvert assessment to determine if any of the culverts will need to be replaced. Culverts could need replacement for structural reasons, or to allow for fish passage. Phasing of the paving plan will take into consideration culverts that need replacement to minimize cutting through new pavement. Culverts that have fish passage requirements involve extensive environmental requirements and long lead times for permitting prior to construction. One such culvert is the Mill Creek Culvert. It is located about 1,600 feet west of Ellsworth Road, as shown on the Attachment map. In August 2015, the culvert was failing structurally so emergency repairs were made as an interim solution to allow time to obtain the required environment permits to construct a new culvert. The new culvert is scheduled for construction in 2018 and will comply with fish passage requirements.
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Utilities The paving plan will be coordinated with local utilities so that street cuts for new utilities can be made before the roadway is resurfaced. New water and sewer mains are currently scheduled for installation between Southeast Ellsworth Road and Southeast 112th Avenue in 2018. Date Stamps The corridor has date stamps from 1919 and 1920 stamped into the PCC roadway. Resurfacing will require the date stamps to be moved so they can be preserved for the future. Before resurfacing is done at a date stamp location, the date stamp will be cut out of the PCC roadway into an approximate 18-inch-by-18-inch square. The date stamps will typically be incorporated into nearby landscaping or an adjacent trail, depending on site features at that location. The locations of 13 date stamps are shown in the table here.
SE Evergreen Pavement Date Stamps - SE Chelsea Avenue to SE 164th Avenue Number Assigned 1 2 3 4 5 6 7 8 9 10 11 12 13
Location
Date Shown on Stamp
230 feet east of 86th Ct 120 feet east of 86th Ct 70 feet west of 80th Ave 60 feet west of Ellsworth 200 feet west of 106th Ave 70 feet west of 105th Ct 100 feet west of 105th Ct 10 feet east of 91st Ave 350 feet west of 91st Ave near center line of 115th Ct 200 feet east of 159th Ct 140 feet east of 158th Ct 370 feet east of Rivercrest Ave
08-??-?? 09-07-20 08-31-20 11-15-20 10-18-20 10-12-20 10-11-20 09-11-20 09-10-20 10-20-19 (only circular stamp) 10-23-20 10-26-20 10-14-20
Note: Information above based on field assessment Aug.3-4, 2016. All stamps shown are located along the south side of Evergreen Corridor, with the exception of the one circular stamp (No. 10), located on the north side of the roadway.
Future Trails Trails are planned along the south side of the corridor from Southeast Chelsea Avenue to Southeast Image Road and from Image to Southeast 100th Court. The trails are currently planned to be 8 feet wide with a 2-foot-wide drainage strip of pervious pavement between the trail and the PCC roadway. The City does not anticipate that the trails will impact the 7
paving plan. Additional information about the future trails is provided in the Evergreen Highway Corridor Management Plan, formally adopted by the Vancouver City Council in October 2016. Traffic Calming The City anticipates that traffic speeds and volumes will increase after the corridor has been resurfaced. Currently, the City is evaluating options for reducing traffic speeds. Traffic calming options will be coordinated with project level pavement design.
RESURFACING OPTIONS The City considered four resurfacing options: roadway reconstruction, microsurfacing, enhanced cape seal, and an HMA overlay. Each of these options is presented below: Reconstruction The reconstruction option would involve removing the existing concrete and replacing it with a traditional HMA roadway. As presented in the Otak memorandum, this option ranged from $18.6-$23.1 million. This is equivalent to $320-$395 per square yard. This option would provide the longest lasting roadway of all the options. However, due to the significantly high cost, this option was eliminated from future consideration for the pavement plan. Microsurfacing This option would be the least expensive of the options at about $10 per square yard, which includes $6 per square yard for surface preparation. Surface preparation includes making concrete repairs, crack filling, and milling. Because of the significant amount of existing cracks, reflective cracks would quickly propagate through the microsurfacing, leaving a rough surface. For this reason, this option was removed from further consideration. The total cost is estimated at approximately $580,000-$620,000. Enhanced Cape Seal An enhanced Cape seal would provide a smoother, longer-lasting surface than just the microsurface. The cost for the enhanced cape without surface preparation would be approximately $13 per square yard. To provide a smoother surface than the 2014 Pilot Project, the PCC roadway surface would be milled, crack filled, and highly distressed 8
concrete areas would be repaired before applying the enhanced cape seal. With surface preparation, the cost would be approximately $19 per square yard, which would provide a smoother surface than the 2014 Pilot Project, but not as smooth as the 2016 Pilot Project. The City estimates the service life of the enhanced cape seal to be about 5-7 years. At that time, an additional treatment such as a microsurface should be applied to its surface to provide another 5-7 years of service life. The total cost of an enhanced cape seal for the corridor would be approximately $1-$1.2 million. HMA Overlay The overlay option would have a similar design as the 2016 Pilot Project. This option would consist of a 3-inch mat of HMA placed directly on a prepared PCC roadway surface. Road preparation would include milling, crack sealing, and roadway repairs, including saw cutting and removing failed concrete. The failed concrete would be replaced with compacted HMA. The City estimates that the cost for an HMA overlay would be about $36 per square yard. This option would provide a smoother driving surface than the enhanced cape seal. The City also estimates that it will have a 10-14-year service life before street maintenance will be needed. After that, street maintenance could consist of microsurfacing or a similar preservation treatment. The total cost to construct an HMA Overlay for the corridor would be about $2.1-$2.3 million. The HMA Overlay would not include a paving grid due to the high cost and the anticipated amount of benefit. If a paving grid is incorporated into the design, the unit cost increases from $36-$48 per square yard. CORRIDOR PARTITIONING PROCESS In its pavement evaluation, the City partitioned the corridor into eight sections. Sections were determined based on corridor access points, locations of new pavements, planned culvert and utility work, and construction cost. Resurfacing the roadway in the corridor will be balanced with other citywide street needs and done as part of the City’s annual Pavement Management Program, which maintains over 1,800 lane miles of street. Corridor sections were designed to be long enough to provide a cost-effective economy of scale, but short enough so that they could be incorporated into the annual budget of the Pavement Management Program. Limiting the length of the sections allows
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the City to better incorporate and address the costs through the annual pavement management budget. It will also help reduce the traffic disruptions during construction. The list below summarizes the characteristics of each section including the surface condition, ride quality, length and preliminary estimates of possible construction costs. The percentage of cracking only includes medium to very high severity cracking. Ride quality was based on a qualitative judgement on how rough the road was while riding in a car. SE Chelsea Avenue to SE Image Road, PCI=37, area cracked= 7.3%, length=6,100 feet
Poor ride quality and about 4 percent of the road will need roadway repairs.
Approximately 40 grade constraints due to side streets and driveways. Two side streets and nine driveways are concrete.
Pavement patching was performed in roughest areas in 2016.
Enhanced Cape Seal: $260,000, HMA Overlay: $490,000
SE Image Road to SE 98th Avenue (2016 Pilot Project), PCI 100, area cracked= 0, length 1,500 feet
Paved in 2016, excellent ride quality.
Approximately 12 grade constraints, which includes three concrete driveways.
Before construction the existing slab had about 7.6 percent cracking. About 3 percent of the concrete was replaced before paving.
Construction Cost: $145,000
SE 98th Avenue to SE 112th Avenue, PCI=38, area cracked= 2.3%, length=4,200 feet
Poor ride quality and less than 1 percent of concrete will need to be replaced.
Approximately 48 grade constraints due to side streets and driveways. Four driveways are concrete. There are also additional grade constraints due to a concrete gutter along the south side of Evergreen from Ellsworth Road to Southeast 112th Avenue.
The east end was selected to allow the ability to incorporate sewer and water main work scheduled for 2018.
Enhanced Cape Seal: $180,000, HMA Overlay: $340,000
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SE 112th Avenue to Fish Hatchery, PCI=49, area cracked= 6.3%, length = 2,800 feet
Very poor ride quality and about 4 percent of concrete would need to be replaced.
This section has approximately 17 grade constraints. There are also additional grade constraints due to a concrete gutter along the south side of Evergreen from Southeast 112th Avenue to Southeast 113th Court and along the north side from Southeast 113th Court to Southeast 115th Court.
Enhanced Cape Seal: $120,000, HMA Overlay: $225,000
Fish Hatchery to SE Silver Springs Drive, PCI=100, area cracked= 0%, length=2,600 feet
Good to excellent ride quality.
Segment was overlaid with approximately 3 inches of asphalt in the summer of 2016. Prior to overlaying the road, the concrete was in very poor condition. Approximately, 25 percent of the road had high severity cracking, which might need to be replaced when a more substantial repair is performed.
This segment has approximately eight grade constraints due to side streets and driveway. None of the grade constraints are concrete.
SE Silver Springs Drive to SE Bella Vista Place, PCI=54, area cracked= 6.5%, length=2,400 feet
Has poor to fair ride quality and about 4 percent of the road will need to be replaced.
No grade constraints.
Paving patching of roughest areas was performed in 2016.
Enhanced Cape Seal: $100,000, HMA Overlay: $190,000
SE Bella Vista Place to SE Rivercrest Avenue, (2014 Pilot Project) PCI=79, area cracked= N/A, length=3,000 feet
Fair ride quality. The road received an enhanced cape seal in 2014.
Approximately eight grade constraints due to side streets and driveways. Four of the grade constraints are concrete. It also has a concrete curb and gutter along the north side of road extending east and west of Southeast 148th Avenue by 230 feet.
Construction cost: $90,000
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SE Rivercrest Avenue to SE 164th Avenue, PCI=39, area cracked= 3.1%, length=3,900 feet
Poor ride quality and about 2 percent of the road will need to be replaced.
Approximately 32 side grade constraints due to side streets and driveways. Seven grade constraints are concrete.
Enhanced Cape Seal: $165,000, HMA Overlay: $310,000
PAVEMENT SCHEDULE Based on the sections described above, the City developed a five-year paving plan from 2017 to 2021 to pave the corridor as shown in the attached SE Evergreen Corridor Pavement Plan Map. Implementing the paving plan over five years allows the City to incorporate corridor resurfacing into the pavement management program and address street maintenance needs of the rest of the City. Scheduling of sections was based ride quality, surface conditions, traffic volume, and future utility projects. The sections that have been recently resurfaced, or have HMA pavements that are still in good condition were not included in the pavement plan schedule. These sections include Southeast Image Road to Southeast 98th Avenue, Fish Hatchery to Southeast Silver Springs Drive, and Southeast Bella Vista Road to Southeast Rivercrest Avenue. The City will schedule these sections for paving or preservation treatments after the City sees how they perform. The first section to be paved will be the section of Southeast 112th Court to the Fish Hatchery. It has the worst ride quality and higher traffic volumes. It also has the second most amount of cracking of the sections. It is scheduled for paving in 2017. The second and third sections to be resurfaced are Southeast Chelsea Avenue to Southeast Image Road and Southeast 98th Avenue to Southeast 112th Avenue. These sections have the second and third worst ride quality. The section from Southeast 98th Avenue to Southeast 112th Avenue will have culvert and utility work in 2018, so this section will be delayed for resurfacing in 2019. The Southeast Chelsea Avenue to Southeast Image Road section will be resurfaced in 2018. The sections from Southeast Rivercrest Avenue to Southeast 164th Avenue and Southeast Silver Springs Drive to Southeast Bella Vista Place will be the fourth and fifth sections to be resurfaced. The ride quality for these sections is slightly better than the other sections, and they also have a relatively
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low amount of cracking. In addition, if the enhanced cape seal needs to be replaced, it can be incorporated into the resurfacing of one of these two sections. CONCLUSION Construction of an HMA overlay option will cost approximately two times as much as the enhanced cape seal. However, an HMA overlay should last twice as long as an enhance cape seal. Because life cycle costs for both options are close, and HMA overlay provides better ride quality, the City selected the HMA overlay option for resurfacing the corridor. The paving schedule for each section is shown on Figure 1. The roadway east of Southeast 164th Avenue will be completed after these sections are completed.
ATTACHMENTS: Evergreen Corridor Pavement Plan Summary Evergreen Corridor Pavement Plan Map
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