Public Works Role in Mitigating Construction Impacts of Private Development

Transcription

1 Public Works Role in Mitigating Construction Impacts of Private Development Trish Aragon, P.E. City Engineer City of Aspen 130 S. Galena Street Aspen, Colorado Abstract A large portion of the development in the City of Aspen is redevelopment. These projects consist of everything from single family homes to large commercial developments. The common factor in all the projects is limited space. Many of the projects build from lot line to lot line leaving little space for constructing the project. This limited space forces the developers to approach the City in using the Right of Way (ROW) to build these projects. In addition to the use of the ROW, the developers often put strains on the neighborhoods with noise, dust and increased traffic associated with the redevelopment. In response to these pressures, the City has developed a construction management program to manage these issues to minimize impact to the traveling public, maintain a resort community atmosphere for its tourists, reduce construction impacts to neighborhoods, while allowing the redevelopment to proceed as quickly as possible. The construction management program includes managing stormwater, noise, dust, aesthetics, and safety to the traveling public.

2 Introduction The City of Aspen is located in the Rocky Mountains at an elevation of 7,908 feet (2,410 meters). It has a year round population of approximately 6,500 people and encompasses 3.6 square miles (9.3 square kilometers). Aspen is a world class summer and winter resort which includes four ski resorts and various summer attractions and events. Due to Aspen s tourist economy, its population increases during the winter and summer months to approximately 30,000 people. The average home price in the City is approximately $4.6 million US dollars. As a result, despite the downturn in the economy, the City of Aspen has experiencing continued redevelopment. Because property values in the City are at such a premium most projects build from lot line to lot line leaving little space for constructing the project. This limited space forces the developers to approach the City in using the Right of Way (ROW) to build these projects. In addition to the use of the ROW, the developers often put strains on the neighborhoods with noise, dust and increased traffic associated with the redevelopment. In the past, complaints that the City received from its citizens regarding construction issues were managed by multiple departments. In response to the construction pressures from developers and its citizens, the City developed a construction management program to manage these issues to minimize impact to the traveling public, maintain a resort community atmosphere for its tourists, reduce construction impacts to neighborhoods, while allowing the redevelopment to proceed as quickly as possible. The construction management program includes managing stormwater, noise, dust, aesthetics, and safety to the traveling public. Discussion In the past construction issues in the City were handled through multiple Departments as they happened. For example the Environmental Department would respond to noise complaints, the Building Department along with Community Development would respond to private property construction related complaints, and the Engineering Department would respond to public property complaints. The City was not only restricted to a reactive position with construction it was also inefficient in its management of these issues. The City s construction management program is now implemented by the Engineering Department. This includes managing City s construction management plan requirements and enforcement. Now the City is not only more responsive but is proactive with construction issues. Page 1

3 Implementation of the construction management program now begins long before the project begins construction. Prior to development some projects receive land use approval. Examples of projects requiring land use approval include developing in environmental sensitive areas, subdivision review, planned unit development review and compliance with the growth management quota system. The land use review includes a Development Review Committee (DRC). This committee consists of various departments within the City including Community Development, Engineering, Water, Electric, Fire, and Sanitary District. DRC is the first opportunity inform the project team of the expected construction impacts of the project and to ensure these impacts are accommodated up front in the design. Most commercial projects in the City will have a building envelope from lot line to lot line while residential projects will typically have 10 5 foot (3 1.5 meter) set backs. So when the project is considering its design it has to account for how it will be excavated and stabilized with out impacting neighboring properties. In the past the City did not allow a project to install earth retention systems with in the right of way. This includes soil nails, micro piles and other systems used to stabilize the project while the foundation is being excavated and constructed. The reasoning for this policy was that these systems though temporary in nature would still affect the future use of the ROW. An example that frequently came up was the use of soil nails and how the utility companies said that although the nails can be removed while installing a utility line, the nails will slow up the duration of the installation. Additionally the City had experienced some poor installations of soil nails where they punctured sanitary lines and proceeded to pump grout into the lines. These issues were not discovered until several months after the incident, when the sanitary line failed and needed emergency repairs. The City received push back on the policy of not allowing earth retention systems in the ROW. Developers wanted to use the ROW for these systems additionally concerns were raised about the safety of systems that only used private property while achieving depths of 40 feet and greater. As a result the City modified its earth retention policy to allow the ROW to be utilized under the following circumstances: The earth retention fixture is sacrificial and can be removed after subsequent structural elements are completed. The system cannot be located under paved surfaces (because most utilities are located under the road way surface, any proposed system will not affect existing or future utilities) The first 7 feet (2 meters) of the system must be removed. (in the event a shallow utility needs to utilize this area the system will not affect them) A minimum overall factor of safety of 1.3 which is consistent with the Geotechnical Engineering Circular No.2, FHWA-IF-O3-017, page 147. (Through the years the City has experienced failures of temporary earth retention system as Page 2

4 a result the City requires a minimum overall factor of safety regardless of the type of temporary system used.) Additionally the City has adopted a fee for these systems the fee is $1.32 per cubic foot per month ($US per cubic meter). The measurement includes the entiree depth and area of the system. For example the City does not calculate the volume of each soil nail ratherr the entire volume of soil the nail system is retaining. The duration of the fee is from the commencement of the construction of the system until the permanent foundation is backfilled. The reasoning behind the fee is that theree will be some type of inconveniencee to the traveling public and neighboring properties when a future utility encounters these systems. This could include a longer duration of installation or a limitation on the type of installation. For example if a utility wanted to use this area to bore its lines but could not bore due to the nails and instead needs to excavate this will have an impact on the area. Figure 1 shows a stabilization plan for a commercial building. This plan does include soil nails in the right of way. In this particularr example, the City permitted the use of earth retention system in the Right of Way to allow the preservation off existing trees on the project site. Figure 1: Stabilization plan of commercial building. Plan includes a combination of soil nails and micro piles. Page 3

5 At the building permit stage, the project is required to submit a construction management plan (CMP). The purpose of this plan is to ensure that project is accounting for all its construction effects and to show how the project will mitigate these impacts. These impacts include environmental, safety, traffic and neighborhood / aesthetic impacts. The plan is unique in that it combines all aspects and impacts of construction in one document. The City s Engineering Department reviews the CMPs and ensures that all elements of the CMP are accurate and in compliance with the City s requirements. Details of the CMP include the following: Environmental: tree protection, materials storage, waste management, recycling, sediment and erosion control, fugitive dust control, emissions and noise suppression. Tree protection. Tree protection fence must be installed around the drip line of trees. Plan must show all tree and natural resource protection measures. Materials storage. Plan must show the location of the job trailer, job materials storage, and portable restrooms. Hazardous material spill clean up kit is required at each site. Waste Management / recycling. Plan must show the location of waste management containers (must be bear proof) and recycling containers. Sites are required to recycle construction materials. Sediment and erosion control. Stormwater management plan must identify best management practices which will minimize erosion and sediment transport. Including covering stockpiles, concrete washout stations and tire washing stations. Sediment and erosion control operations shall be managed by a state certified erosion control supervisor. Fugitive dust control. Plan must address how the site will properly prevent and control dust. Projects are required to water their sites three times a day. Emissions. Diesel engine emissions shall be of a shade density no darker than 40% opacity. Noise suppression. Noise suppression plan must include installation of noise barriers. Sites are restricted to 80 decibels at the property line. There are additional restrictions to activities considered as manufacturing. Activities will be considered manufacturing if alterations to a material that is readily available on the market are made in order for the material to meet the needs of the end user. These activities are limited to 90 days. Page 4

6 Figure 2: Residential construction site. Safety: project fencing, barriers, pedestrian protection Project fencing. Six foot chain link fencing must be placed around the perimeter. Barriers. Where the excavation occurs next too a driving surface, a concrete barrier must be placed between the project site and the driving lane. Pedestrian protection. Pedestrian access mustt be maintained around the project site. In most cases it will include an engineered scaffold system, as seen in Figure 3, which minimizes the use of ROW. Page 5

7 Figure 3: Pedestrian protection with the use of engineered scaffold system. Traffic: staging, haul routs, access locations, deliveries Staging. The number of truckloads expected to and from the site is estimated (including soil hauling and materials transport). The timing and duration of the transport vehicles is also estimated. Projects that have little or no setbacks are required to use a tower crane as shown in Figure 4. Haul Routes. Project follows the City s designated routess and the plan specifies additional routes necessary to complete hauling operations. Project haul routes are oriented to minimize traffic congestion and maximize pedestrian safety. Access locations. Access for the project mustt be located in order to minimize impacts to neighboring properties. Deliveries. Maximumm number of delivery vehicles must be specified, along with the hours the deliveries will occur. Delivery vehicles must have a visible sign on the vehicle that specifies the project contractor s name and phone number. Vehicles are not allowed to idle for more thann five minutes. Page 6

8 Figure 4: Use of an electric tower crane on a constrained site. Aesthetic / Neighborhood: Visual screening, parking management, project notification. Visual screening. Mesh windscreen or decorative construction fences must be installed around the perimeter of the project. Parking management. Parking plan must be submitted. The parking plan includes the amount of spaces requested for subcontractors and contractors involved in the site construction process. The city will only permit a limited amount of spaces for a site. Project notification. Preconstructi ion meeting with neighboring properties and applicable City departments is required to summarize the project construction management plan. Monthly project updates are required. They must include a description of the current phase, traffic and pedestrian impacts, hauling and staging impacts. Updates must be specificallyy distributed to neighbors located with in 300 feet of the property. Project sign must be posted at the project site as shown in Figure 5. Page 7

9 Figure 5: Example project sign. In addition to the constructionn management plan, projects are required to permit any activities which occur in the right of way. This permitting includes: Right of Way (ROW) permit. Any construction activity which disturbs the ground surface including utility, sidewalk, and curb and gutter, and landscape installations require a ROW permit. Issuancee of ROW permits are not permitted in the winter months and in the peak summerr months in the downtown area. Permits are restricted in the winter months because the availability of materials during this time of year is limited. Permits are restricted in the peak summer months in the downtown area to maintain a tourist environment. Encroachment permit. Any construction activity which occupies the ROW, including pedestrian walkways, construction staging and construction materials. Encroachment permits are not permitted in the roadway or sidewalk during the winter months. Encroachment permits are also not permitted in the downtown area during the peak summer months. Permits are restricted in the winter months to allow for snow removal operations. Permits are restricted in the downtown area inn the peak summer months in order to maintain a tourist environment. The fees associated with encroachment permits are structured to encourage sites to minimize their amount of encroachment in n the ROW. Location Feee per month Downtown Core Area $US 5.44/ SF ( $US / Sq. Meter) Outside Core Area $US 2.72/ SF ( $US / Sq. Meter) Table 1: Fees for occupying row space for construction. Page 8

10 Parking permits. Construction parking permits are required for all parking associated with construction. These permits are limited per site depending on the size of the site. Typically three spaces are granted per site. Active permit locations and project details are available on the City s web site through an interactive map as seen in Figure 6. The map graphically displays active permit locations throughout the city. Users can click on a property or a permit to display the details of the construction associated with that property. This makes this information accessible to anybody interested in what is going on with any project in the City. Figure 6: Interactive permit location map. Having the CMP requirements are not effective without enforcement. The City s Engineering Department employs construction mitigation officers to enforcee the requirements of the CMP. These officers patrol the city to ensuree that the project sites are in compliance with their CMPs. They also work closely with contractors and neighboringg property owners to resolve construction related disputes and complaints. In order to pay for this service permits are charged a constructionn mitigation fee. The feee is $1 per gross square foot of a building ($US per square meter). The City also offers an incentive if a project progressess without a red tag or no more than two Page 9

11 correction notices. The incentive is 10% of the construction mitigation fee and paid back to the applicant at the time of the certificate of occupancy. Conclusion With the use of a construction management program, the City has been able to become proactive with construction issues instead of reactive. In the past the City was responding to random complaints around the City as they were occurring. Now construction issues are identified long before the project breaks ground. All development sites must have a construction management plan. This plan addresses how the project will mitigate its environmental, safety, traffic and neighborhood / aesthetic impacts. Implementation of the CMP requirements is centralized in the City s Engineering Department which allows the City to become not only more responsive but proactive with construction related issues. References City of Aspen Construction Management Plan Requirement Manual can be located at : City of Aspen Encroachment and ROW permit requirements can be located at: City of Aspen Construction Site Map can be located at: Page 10