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HomeMy WebLinkAbout05 project narrative (2)Project Narrative I-405 / SR 167 Direct Connector September 30, 2016 Purpose WSDOT is requesting a noise variance from the requirements of City of Renton Municipal Code to allow nighttime construction work for 845 non-consecutive nights over a period of 36 months.   Project Description The I-405 / SR 167 Interchange in Renton, Washington is one of the most heavily congested interchanges in the state. Today, drivers experience congestion in this area for up to eight hours each day. WSDOT will build a new flyover ramp connecting the HOT lanes on SR 167 to the carpool lanes on I-405, improving flow at this critical interchange. The project work included in the noise variance request will reconstruct portions of the nearby local streets, relocate a noise wall, and add a raised earthen berm. The noise variance request also includes geotechnical explorations on the shoulder of both the on-ramps and off-ramps and the highways within the project limits. It stretches from MP 24.5 at S 180th St. to MP 27.3 at I-405 on SR 167, and MP 1.3 at to MP 4.3 at N 4th St. on I-405. The work will occur between November 22nd 2016 and November 21st 2019. Congestion/Safety: The project will reduce delays and weaving, as well as the likelihood of collisions. Drivers will no longer need to exit the carpool or HOT lanes, merge onto I-405 or SR 167, and merge across traffic again to the carpool or HOT lanes. Environment: This project will relocate a noise wall, build storm-water management facilities, and upgrade or replace a stream crossing at SR 167 to promote fish passage. Economic: This project provides better transit access to affordable housing and employment centers, expands freight mobility to the Green River Valley cities warehousing and distribution centers, and creates construction jobs in a variety of trades. The Design-Build project has been awarded to Atkinson Construction, and work activities related to survey of existing conditions and preliminary design have already begun. Project Narrative Project name, size and location of site Project Name: Noise Variance for I-405 / SR 167 Direct Connect Project Project Size: The project area includes widening of ramps, roadway, and construction of a new flyover between I-405 and SR 167. It is 12,612.5 ft long. Project Location: The project is located between S 180th St over SR 167 North to I-405 and Northeast up I-405 to N 3rd St., and geotechnical subsurface explorations are required for shoulders of roads and ramps for the highways. Land use permits required for proposed project. Land use permits are not required for this project. A Nighttime Noise Variance, variance in allowed hours of construction, and a variance in the hours of hauling is needed. Zoning designation of the site and adjacent properties. I-405 roadway and associated off/on ramps are within State roadway right of way and do not have a City zoning designation. Beyond the State roadway right of way the land use is designated Commercial Office (CO), Medium Industrial (IM), Commercial Downtown (CD), Commercial Arterial (CA), Residential du/ac (R-6, R-8, R-10), and Residential Multi-Family (RMF). Current use of the site and any existing improvements The current land use is a state transportation corridor including intersections with off and on-ramps. Existing improvements are associated with the roadway. They include on and off-ramps, electrical cabinetry and wiring, ditches, culverts, catch basins, storm water treatment facilities, pavement markings, traffic signals, signs and ramp meters. Special site features (i.e. wetlands, water bodies, steep slopes) Cedar River flows beneath I-405 near Cedar River Trail. Impacts to the Cedar River are not anticipated. Other streams in the project area include Thunder Hills Creek, Rolling Hills Creek, and West Fork of Panther Creek. There are a total of 16 wetlands located in the project area. The project is not located within a landslide hazard area. Soil type and drainage conditions The major soil type identified along the project is glacial till and advance glacial outwash deposits. However due to intense urbanization and previous I-405 construction, there is little natural soil within the project area. Surface water runoff from the existing roadway drains through a combination of open ditches and enclosed pipes. Minor roadway widening will occur on both I-405 and SR 167.  An enclosed drainage will be provided and connected into WSDOT’s existing enclosed drainage system at the on-ramp, within WSDOT right of way. NPDES The project will have an NPDES permit once ground-disturbing construction begins in January or February of 2017. Best Management Practices will further ensure compliance with State water quality standards. New impervious surface The project is still in design. Some new impervious surfaces will be added, and some will be deleted. The project provides treatment for all new impervious surfaces. Proposed use of the property and scope of the proposed development No change of land use will occur. The property will remain a transportation corridor. For plats indicate the proposed number, net density and range of sizes (net lot area) of the new lots Not applicable. This property is and will remain a transportation corridor. Access Site access will not change. Proposed off-site improvements (i.e. installation of sidewalks, fire hydrants, sewer main, etc.) None. Total estimated construction cost and estimated fair market value of the-proposed project. Construction cost and the fair market value is approximately $115,000,000. Estimated quantities and type of materials involved if any fill or excavation is proposed. Approximately 250,000 cubic yards excavation and 110,000 cubic yards common borrow will be needed to construct the interchange improvements. Number, type and size of any trees to be removed. None. Explanation of any land to be dedicated to the City None. Any proposed job shacks, sales trailers, and/or model homes A WSDOT/Contractor/Designer combined jobsite office trailer and storage yard will be located at 3000 East Valley Road, Renton WA 98057. Any proposed modifications being requested (include written justification) None. For projects located within 100 feet of a stream or wetland, please include distance in feet from wetland or stream to nearest area of work The Project will include improvements to the Rolling Hills Creek as it passes under SR 167. For projects located within 200-feet of Black River, Cedar River, Springbrook Creek, May Creek and Lake Washington please include the following additional information: Distance from closest area of work to the ordinary high water mark. Description of the nature of the existing shoreline The approximate location of and number of residential units, existing and potential, that will have an obstructed view in the event the proposed project exceeds a height of 35-feet above the average grade level The project is not within 200-feet of Black River, Springbrook Creek, May Creek or Lake Washington. The project limits on I-405 do extend from SR 167 to north of the Cedar River so in plan view the project is over the Cedar River. In the location of the Cedar River the scope of the project is limited to ITS (fiber optic) cable replacement and will have no impact on the Cedar River. Specifically: The ITS fiber cable replacement will be on the bridge over the Cedar River well above the OHW mark. The existing shoreline will not be affected. The proposed project will not construct structures in the Cedar River area or obstruct any views. Variance Request Justification: The burden of proof as to the appropriateness of the application lies with the applicant. In order to approve a variance request, the Reviewing Official must find all the following conditions exist: The applicant suffers practical difficulties and unnecessary hardship and the variance is necessary because of special circumstances applicable to subject property, including size, shape, topography, and location or surroundings of the subject property, and the strict application of the Zoning Code is found to deprive subject property owner of rights and privileges enjoyed by other property owners in the vicinity and under identical zone classification; WSDOT’s traffic analysis has determined that performing ramp and lane closures during the day would result in traffic congestion due to high traffic volumes, loss of roadway capacity, and diminished access to local events. WSDOT requires that lane closures and certain construction activities occur at night and continuous operation of construction activities such as pavement grinding can be ensured to avoid endangering personnel. To avoid disruptions to workers, pedestrians and motorists, and to maintain emergency and essential services, many construction activities must occur between the hours of 7:00 pm and 7:00 am, Monday through Sunday. Activities such as pavement repair, grinding, removal and replacement of pavement and pavement markings cannot be accomplished while traffic is present. Full or partial freeway, street and ramp closures are necessary for these activities. Construction Considerations and Closures: Portions of the construction operations will occur during nighttime hours (7pm to 7am). The closures required for these operations are only feasible at night. This project will require roadway closures for construction personnel and equipment and personnel operating on the roadway. Estimate of required night work WSDOT estimates that it will require 840 consecutive or non-consecutive nights to complete the work. This estimate, shown below, includes the minimum amount of time necessary to safely complete the work: Subsurface site investigations and survey 100 nights I-405 Widening 260 nights SR 167 Widening 280 nights Direct Connect Bridge 100 nights Final Paving 100 nights                          Total estimated nights                                                        840 nights Contingency nights for weather and other factors               5 nights Total Estimated night work                                                   845 nights        This includes construction activities and hauling Monday through Sunday, 24 hours a day, 7 days a week.  The granting of the variance will not be materially detrimental to the public welfare or injurious to the property or improvements in the vicinity and zone in which subject property is situated; Granting of the variance will enhance public safety and reduce risks to property because nighttime traffic volumes are lighter, thus reducing the safety risks. Performing this work during nighttime hours and, if required, during weekend closures when the least amount of traffic is present will minimize risks to the traveling public and construction workers. In addition to the safety benefits of nighttime work, WSDOT, its contractors and subcontractors will follow all of the conditions, restrictions and mitigation measures pursuant to the City of Renton Municipal Code. Those mitigation measures will include: Noise Variance: A copy of each noise variance or exemption will be kept on the project site at all times for presentation on demand to law and code enforcement agencies. Notifications: Notification will be submitted to residents and businesses potentially affected as to the nature and duration of nighttime construction activities that could result in a noise exceedance. This notice will provide the resident or business with the telephone number of a contact person available during non-working hours. Training: All workers on the project will attend Environmental Awareness Training and the Noise Variance provisions will be discussed. Backup Alarms: Use manually adjustable alarms set 87 dba at night. Configure traffic pattern to minimize backing movements. Slamming Tailgates: Establish truck clean-out areas. Use rubber gaskets on truck gates. Decrease speed of truck gate closure. Prolonged idling of equipment: Enforce “no idling” policy. Equipment Staging and Shielding: To the extent possible, stationary equipment will be located away or shielded from sensitive receptors such as residences to decrease noise. Noise Wall Sequence: Schedule construction of the new noise wall shafts prior to removing the existing noise wall. This minimizes the period of time the Talbot Hill neighbors are not protected from freeway noise. Noise Monitoring: Implementation of a noise monitoring program will be conducted nightly by the contractor, and the results provided to the City’s Project Manager. A list of equipment with the noise level each piece generates is included in the attachments for reference. The highest and lowest noise generated from this list is 85 and 64 with an average between those two of 75 dB. Existing ambient noise levels are in the range of 70 to 80 dBA which may aid in masking the construction noise. Some of the nighttime work will be mobile and occur up and down the corridor and will not be focused on one particular neighbor within the project limits. The approval shall not constitute a grant of special privilege inconsistent with the limitation upon uses of other properties in the vicinity and zone in which the subject property is situated; and WSDOT agrees that the approval is the minimum variance that will accomplish the desired purpose. Approval of this request does not grant a special privilege inconsistent with roadway construction projects elsewhere. Nighttime roadway construction is a common and accepted practice to reduce congestion and inconvenience to motorists, expedite road building tasks, and enhancing work zone safety by conducting construction when partial or complete roadway and ramp closures are possible due to reduced traffic volumes. Utilities Plan, Generalized (sewer, water storm water, transportation improvements) See attached conceptual plans for details. Other Attachments See attached Neighborhood Detail Map, and a list of equipment with noise levels that each generates.