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HomeMy WebLinkAbout31-2319-Dewatering_Rev_1Dennis Yarmouth Intermediate Middle School January 19, 2021 Dennis Yarmouth Regional School District 100% Construction Documents Perkins Eastman DPC, project #71011 31 2319 Dewatering 1 of 5 31 2319 Dewatering PART 1 - GENERAL 1.1 GENERAL PROVISIONS A. Attention is directed to the CONTRACT AND GENERAL CONDITIONS and all Sections within DIVISION 01 - GENERAL REQUIREMENTS which are hereby made a part of this Section of the Specifications. 1.2 DESCRIPTION OF WORK A. Work Included: Provide labor, materials and equipment necessary to complete the work of this Section, including but not limited to the following: 1. Construction dewatering. B. Alternates: Not Applicable. C. Items To Be Installed Only: Not Applicable. D. Items To Be Furnished Only: Not Applicable. E. Related Work: The following items are not included in this Section and will be performed under the designated Sections: 1. Section 31 2000 – EARTH MOVING for soil materials, excavating, backfilling, and grading for the building, structures, slabs on grade, walls and foundations. 2. Section 31 0000 - EARTH WORK for excavating, backfilling, site grading, and for site utilities. 3. Section 31 5000 - EXCAVATION SUPPORT AND PROTECTION for shoring, bracing, and sheet piling of excavations. 4. Provision of waste management: Section 017419, Construction of Waste Management Plan. 5. Provision of General LEED requirements and forms: 018113 Sustainable Design Requirements. 1.3 PERFORMANCE REQUIREMENTS A. Dewatering Performance: Design, furnish, install, test, operate, monitor, and maintain dewatering system of sufficient scope, size, and capacity to control hydrostatic pressures and to lower, control, remove, and dispose of ground water and permit excavation and construction to proceed on dry, stable subgrades. 1. Delegated Design: Design dewatering system, including comprehensive engineering analysis by a qualified professional engineer registered in the Commonwealth of Massachusetts, using performance requirements and design criteria indicated. All costs for delegated design shall be included in the bid price for the Work of this Section. Dennis Yarmouth Intermediate Middle School January 19, 2021 Dennis Yarmouth Regional School District 100% Construction Documents Perkins Eastman DPC, project #71011 31 2319 Dewatering 2 of 5 2. Test liquids for hazardous waste at start of construction operations and provide on-site remediation as acceptable to authorities having jurisdiction. 3. Continuously monitor and maintain dewatering operations to ensure erosion control, stability of excavations and constructed slopes, that excavation does not flood, and that damage to subgrades and permanent structures is prevented. 4. Prevent surface water from entering excavations by grading, dikes, or other means. 5. Accomplish dewatering without damaging existing buildings, structures, and site improvements adjacent to excavation. 6. Remove dewatering system when no longer required for construction. 1.4 SUBMITTALS A. Shop Drawings: For dewatering system. Show arrangement, locations, and details of wells and well points; locations of risers, headers, filters, pumps, power units, and discharge lines; and means of discharge, control of sediment, and disposal of water. 1. Include layouts of piezometers and flow-measuring devices for monitoring performance of dewatering system. 2. Include a written plan for dewatering operations including control procedures to be adopted if dewatering problems arise. B. Delegated-Design Submittal: For dewatering system indicated to comply with performance requirements and design criteria, including analysis data signed and sealed by the qualified professional engineer responsible for their preparation. C. Qualification Data: For qualified Installer D. Field quality-control reports. E. Other Informational Submittals: 1. Photographs: Show existing conditions of adjoining construction and site improvements that might be misconstrued as damage caused by dewatering operations. 1.5 QUALITY ASSURANCE A. Installer Qualifications: An experienced installer that has specialized in dewatering work. B. Regulatory Requirements: Comply with governing EPA notification regulations before beginning dewatering. Comply with hauling and disposal regulations of authorities having jurisdiction. C. Preinstallation Conference: Conduct conference at Project site to comply with requirements in Division 01. 1. Review methods and procedures related to dewatering including, but not limited to, the following: a. Inspection and discussion of condition of site to be dewatered including coordination with temporary erosion control measures and temporary controls and protections. b. Geotechnical report. Dennis Yarmouth Intermediate Middle School January 19, 2021 Dennis Yarmouth Regional School District 100% Construction Documents Perkins Eastman DPC, project #71011 31 2319 Dewatering 3 of 5 c. Proposed site clearing and excavations. d. Existing utilities and subsurface conditions. e. Coordination for interruption, shutoff, capping, and continuation of utility services. f. Construction schedule. Verify availability of Installer's personnel, equipment, and facilities needed to make progress and avoid delays. g. Testing and monitoring of dewatering system. h. Control of dewatering equipment during non-work hours. 1.6 PROJECT CONDITIONS A. Interruption of Existing Utilities: Do not interrupt any utility serving facilities occupied by the Town of Yarmouth or others unless permitted under the following conditions and then only after arranging to provide temporary utility according to requirements indicated: 1. Notify Town of Yarmouth Project Manager no fewer than two days in advance of proposed interruption of utility. 2. Do not proceed with interruption of utility without the Town of Yarmouth Project Manager’s written permission. B. Project-Site Information: A geotechnical report has been prepared for this Project and is available for information only. The opinions expressed in this report are those of geotechnical engineer and represent interpretations of subsoil conditions, tests, and results of analyses conducted by geotechnical engineer. The Town of Yarmouth will not be responsible for interpretations or conclusions drawn from this data. 1. Make additional test borings and conduct other exploratory operations necessary for dewatering. 2. The geotechnical report is referenced elsewhere in the Project Manual. C. Survey Work: Engage a qualified land surveyor or professional engineer licensed in the Commonwealth of Massachusetts to survey adjacent existing buildings, structures, and site improvements, establishing exact elevations at fixed points to act as benchmarks. Clearly identify benchmarks and record existing elevations. 1. During dewatering, regularly resurvey benchmarks, maintaining an accurate log of surveyed elevations for comparison with original elevations. Promptly notify Designer if changes in elevations occur or if cracks, sags, or other damage is evident in adjacent construction. PART 2 - PRODUCTS (Not Used) PART 3 - EXECUTION 3.1 PREPARATION A. Protect structures, utilities, sidewalks, pavements, and other facilities from damage caused by settlement, lateral movement, undermining, washout, and other hazards created by dewatering operations. Dennis Yarmouth Intermediate Middle School January 19, 2021 Dennis Yarmouth Regional School District 100% Construction Documents Perkins Eastman DPC, project #71011 31 2319 Dewatering 4 of 5 1. Prevent surface water and subsurface or ground water from entering excavations, from ponding on prepared subgrades, and from flooding site and surrounding area. 2. Protect subgrades and foundation soils from softening and damage by rain or water accumulation. B. Install dewatering system to ensure minimum interference with roads, streets, walks, and other adjacent occupied and used facilities. 1. Do not close or obstruct streets, walks, or other adjacent occupied or used facilities without permission from the Town of Yarmouth’s Project Manager and authorities having jurisdiction. Provide alternate routes around closed or obstructed traffic ways if required by authorities having jurisdiction. C. Provide temporary grading to facilitate dewatering and control of surface water. D. Monitor dewatering systems continuously. E. Promptly repair damages to adjacent facilities caused by dewatering. F. Protect and maintain temporary erosion and sedimentation controls, which are specified in Section 31 2500 - EROSION AND SEDIMENTATION CONTROLS during dewatering operations. 3.2 INSTALLATION A. Install dewatering system utilizing wells, well points, or similar methods complete with pump equipment, standby power and pumps, filter material gradation, valves, appurtenances, water disposal, and surface-water controls. 1. Space well points or wells at intervals required to provide sufficient dewatering. 2. Use filters or other means to prevent pumping of fine sands or silts from the subsurface. B. Before excavating below ground-water level, place system into operation to lower water to specified levels. Operate system continuously until drains, sewers, and structures have been constructed and fill materials have been placed or until dewatering is no longer required. C. Provide an adequate system to lower and control ground water to permit excavation, construction of structures, and placement of fill materials on dry subgrades. Install sufficient dewatering equipment to drain water-bearing strata above and below bottom of foundations, drains, sewers, and other excavations. 1. Do not permit open-sump pumping that leads to loss of fines, soil piping, subgrade softening, and slope instability. D. Reduce hydrostatic head in water-bearing strata below subgrade elevations of foundations, drains, sewers, and other excavations. 1. Maintain piezometric water level a minimum of 24 inches below surface of excavation. E. Dispose of water removed by dewatering in a manner that avoids endangering public health, property, and portions of work under construction or completed. Dispose of water and sediment in a manner that avoids inconvenience to others. Provide sumps, sedimentation tanks, and other flow-control devices as required by authorities having jurisdiction. Dennis Yarmouth Intermediate Middle School January 19, 2021 Dennis Yarmouth Regional School District 100% Construction Documents Perkins Eastman DPC, project #71011 31 2319 Dewatering 5 of 5 F. Provide standby equipment on site, installed and available for immediate operation, to maintain dewatering on continuous basis if any part of system becomes inadequate or fails. If dewatering requirements are not satisfied due to inadequacy or failure of dewatering system, restore damaged structures and foundation soils at no additional expense to the Town of Yarmouth. 1. Remove dewatering system from Project site on completion of dewatering. Plug or fill well holes with sand or cut off and cap wells a minimum of 36 inches below overlying construction. G. Damages: Promptly repair damages to adjacent facilities caused by dewatering operations. 3.3 FIELD QUALITY CONTROL A. Observation Wells: Provide, take measurements, and maintain at least the minimum number of observation wells or piezometers indicated; additional observation wells may be required by authorities having jurisdiction. 1. Observe and record daily elevation of ground water and piezometric water levels in observation wells. 2. Repair or replace, within 24 hours, observation wells that become inactive, damaged, or destroyed. In areas where observation wells are not functioning properly, suspend construction activities until reliable observations can be made. Add or remove water from observation-well risers to demonstrate that observation wells are functioning properly. 3. Fill observation wells, remove piezometers, and fill holes when dewatering is completed. B. Provide continual observation to ensure that subsurface soils are not being removed by the dewatering operation. END SECTION (THIS PAGE IS BLANK)