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HomeMy WebLinkAboutCorrespondenceOctober 22, 2019 Mr. Jeremy Kashman City Engineer One Civic Square Carmel, Indiana 46032 Re: Intuitive Health (DP/ADLS 19030003) 10830 N Michigan Road Variance Request to allow pipe cover less than 2.5 feet, per Section 501.01 of the Stormwater Technical Standards Manual Dear Mr. Kashman: On behalf of our client, we respectfully request a variance of technical standards to allow portions of the proposed storm sewer (private) to be installed with less than 2.5 feet of cover in grass and paved areas due to existing site constraints. We are proposing 1.9 feet of cover for structure #109 for only the portion of the storm sewer outside the pavement limits. We are proposing 2.1 to 2.4 feet of cover on the storm structures along the south boundary of the site (#100, #101, #102, and #103) in order to provide pedestrian and vehicular connectivity to the Bank of America property to the south. The connectivity is required by the City of Carmel. We offer the following reasons for support of the variance: 1) The connectivity requirement results in the proposed grades dropping from north to south towards the Bank of America property. Subsequently we have placed storm inlets along the south edge of the parking and drive in order to intercept as much stormwater runoff as possible. 2) The storm sewers for this project are private and will be maintained by the Owner of the property. 3) The proposed storm sewers are RCP Class III. This pipe needs at least 2 feet of cover of Class I bedding (granular compacted to 95%) to provide AASHTO HL-93, per the 2017 ACPA LRFD Fill Height Tables. 4) The shallowest cover will be under the curbs or grass, which will not be subjected to vehicular loading on a day to day basis. We believe even though we are not providing the minimum cover stipulated in the ordinance, we are providing enough cover to not compromise the structural integrity of the proposed storm sewer. We appreciate your time and consideration of our request. If you have any questions, please feel free to contact me at our office at (317) 547-5580. Very truly yours, American Structurepoint, Inc. Colin R. Patterson, PE