SHI Builders West Orange NJ Prelim GI SWM Report 1

soil zones. Unsuitable materials should be overexcavated prior to placing new fill materials where site grades are to be raised. The extent of overexcavation can be estimated based on an evaluation of the final site grading plans, structural loading conditions, foundation plans, and supplemental geotechnical investigation. Furthermore, the proposed building footprint/interior column foundation locations should be located by a professional surveyor prior to performing overexcavation operations. Settlement: Once design loading conditions have been determined, settlement evaluation associated with the proposed structure will be required as part of the final evaluation. SHI Builders 9 4266-99-001E

Frost Coverage Embedment Depth: Footings subject to frost action should be placed at least 36 inches below adjacent exterior grades or as required by the local building code to provide protection from frost penetration. If applicable, interior footings not subject to frost action (including during the period of construction) may be placed at a minimum depth of 18 inches below the slab subgrade. 5.3 Preliminary Floor Slab Recommendations Dynamic Earth anticipates that approved structural fill placed and/or on-site soils will be suitable for support of the proposed floor slabs provided these materials are properly evaluated, compacted and proofrolled in accordance with Sections 5.2 and 5.3 of this report. Due to the existing fill and moisture sensitive on-site soils encountered, the contractor should anticipate at least partial overexcavation and replacement and/or subgrade stabilization within the area of proposed floor slab. Depending on construction phase evaluation, overexcavation may be limited with the use of subgrade stabilization techniques, such as geogrid stabilization, as directed by Dynamic Earth. Any areas of the slab that become softened or disturbed as a result of wetting and/or repeated exposure to construction traffic should be removed and replaced with compacted structural fill. The properly prepared on-site soils are preliminarily expected to yield a minimum subgrade modulus (k) of 125 psi/in. A minimum four-inch layer of stone should be installed below the floor slabs to provide a capillary break. A vapor barrier beneath the floor slab is recommended. Total and post-construction settlements of floor slabs installed in accordance with the recommendations outlined in this report are estimated to be less than one-quarter inch. 5.4 Preliminary Earthwork Considerations Demolition and Surface Cover Stripping: Prior to the start of construction, all utilities should be identified and secured. If encountered, existing structural elements, such as concrete foundations, slabs, and remnant basement walls, should be removed entirely from below proposed foundations and slabs and excavated to at least two feet below pavement subgrades. Remnant structural elements may remain in-place below these depths below pavements provided they do not interfere with future construction. Any slabs left in-place should be thoroughly fractured to promote

nt structural elements may remain in-place below these depths below pavements provided they do not interfere with future construction. Any slabs left in-place should be thoroughly fractured to promote vertical drainage in the presence of a qualified Geotechnical Engineer and should be backfilled with structural fill in accordance with the recommendations included herein. The surface cover materials, including vegetation and topsoil, should be removed from within, and at least five feet beyond, the limits of the proposed building and new pavement areas as well as any other area which will require fill placement. If required, removal of any trees should include root mats and tree stumps. As evident by the soil profile pits performed, relatively deeper root mats should be anticipated. The contractor is responsible for restoring grades with structural fill SHI Builders 10 4266-99-001E

following removal of deeper topsoil and root mat layers. Difficult Excavation and Rock Excavation: Weathered rock/rock was encountered at depths as shallow as approximately 2.3 feet below existing site grades. In addition, difficult excavation was encountered apparent cobbles/boulders within the test pits. As such, depending on the final site grading plans, Dynamic Earth anticipates removal of weathered rock/rock and/or oversized materials will be required within excavations for the proposed buildings and/or utility installation. Conventional excavation equipment with rock ripping tools may be effective to remove only the uppermost weathered rock and/or rock. The speed and ease of excavation will depend on the type of grading equipment, the skill of the equipment operators, and the structure of the material itself. Planned excavation depths beyond refusal depths will likely require pneumatic hammers to remove the rock. Surface Preparation/Proofrolling: Prior to placing any fill or subbase materials to raise or restore grades to the desired building pad or pavement subgrade elevations, the existing exposed soils should be compacted to a firm and unyielding surface with several passes in two perpendicular directions with a minimum 10-ton vibratory, smooth drum roller during favorable moisture conditions. The drum roller should be operated in the static mode or a kneading “sheepsfoot” roller should be used where fine-grained soils are encountered at the subgrade elevation and/or where groundwater is suspected near subgrade elevations. The surface then should be proofrolled with a loaded tandem axle truck in the presence of Dynamic Earth to help identify soft or loose pockets which may require removal and replacement or further investigation. Dynamic Earth anticipates at least partial overexcavation if the subgrade is wetted or subjected to repeated construction traffic. Any fill or backfill should be placed and compacted in accordance with Section 5.3. Subgrade Protection and Inspection: Portions of the on-site soils are considered to be extremely moisture sensitive and every effort should be made to minimize disturbance of the on-site soils by construction traffic and surface runoff. These materials will likely become unsuitable if exposed to moisture and/or construction traffic. If the onsite soils become overly wetted, increased handling such as

ction traffic and surface runoff. These materials will likely become unsuitable if exposed to moisture and/or construction traffic. If the onsite soils become overly wetted, increased handling such as discing and drying during extended periods of favorable weather and/or subgrade stabilization may be required. Common stabilization for marginally unsuitable subgrades includes installation of geogrid (such as Tensar TX-5 of TX-7), mixing with granular soils and or chemical stabilization (lime or cement mixing). If required, the subgrade stabilization should be reviewed by the geotechnical engineer during construction. Dynamic Earth should be retained as the Geotechnical Engineer of Record to inspect soil conditions during construction and verify the suitability of prepared foundation, floor slab and pavement subgrades for support of design loads. SHI Builders 11 4266-99-001E

Subgrade Stabilization and Inspection: The on-site soils are considered to be extremely moisture sensitive and every effort should be made to minimize disturbance of the on-site soils by construction traffic and surface runoff. The on-site soils will likely become unsuitable if exposed to moisture and/or construction traffic. If these materials become overly wetted, the on-site soils will likely require increased handling such as discing and drying during extended periods of favorable weather and/or partial overexcavation and stabilization. A triaxle geogrid such as Tensar TX-5 of TX-7 or mixing with granular soils, may be considered where excessively soft or pumping conditions are encountered, as directed by the geotechnical engineer. The subgrades should be sealed daily and construction traffic be minimized to designated non- structural areas and following periods of precipitation as an attempt to minimize deterioration of otherwise suitable subgrade soils. Dynamic Earth should be retained as the Geotechnical Engineer of Record to inspect soil conditions during construction and verify the suitability of prepared foundation, floor slab and pavement subgrades for support of design loads. Import/On-site Structural Fill Material: Soils placed as structural fill material should consist of well graded sand or gravel with a maximum particle size of three inches in diameter and less than 15 percent of material passing the number 200 sieve. These materials should be free of objectionable debris (clay clumps, organic and/or deleterious material, etc.) and within moisture contents suitable for compaction. Alternative soil types with higher percentages of silt and clay may be considered, provided that the contractor is able to achieve proper compaction and maintain suitable subgrade once the material is placed. Fine-grained soils and/or granular soils with higher percentages of silt and clay are extremely moisture sensitive and will only be suitable for reuse as structural fill material under ideal weather conditions. Materials wetted beyond the optimum moisture content; that contain oversized rock or debris; or with increased amounts of objectionable debris will not be suitable for reuse as structural fill material without special handling. As such, the contractor should be responsible for importing structural fill material and/or processing on-site soils as

not be suitable for reuse as structural fill material without special handling. As such, the contractor should be responsible for importing structural fill material and/or processing on-site soils as required so that these materials are suitable for structural fill placement. If encountered, cobbles, boulders and/or oversized debris greater than three inches in diameter will need to be separated from material to be placed as structural fill. Approved material between three to 12 inches in diameter may be crushed or individually placed in fill layers deeper than two feet below proposed subgrade levels. Care must be taken to individually seat any large particles and to compact soil around large particles with hand operated equipment to minimize the risk of void formation. The larger material should not be placed near areas of the proposed utility or planned excavation. Boulders larger than approximately 12 inches are not expected to be adequate for use as fill or backfill and should be removed from the site or crushed to an adequate size. The on-site soils encountered included existing fill material, natural glacial deposits, natural residual soils, and weathered rock/rock. Portions of these materials (above the zone of saturation) are preliminarily expected to be suitable for reuse as structural fill material, SHI Builders 12 4266-99-001E

provided moisture contents are within tolerable limits to achieve compaction and that oversized materials/deleterious debris (if encountered) are segregated. Portions of the on-site soils are considered moisture sensitive and will require moisture conditioning during a period of favorable weather, mixing with granular soils, and/or chemical stabilization (such as lime or cement mixing), and/or will become impractical for reuse if exposed to moisture. As such, the contractor should include a unit rate for importing structural fill material and exporting unsuitable material. Reuse of these materials will be contingent upon further evaluation during construction. Compaction and Placement Requirements: Structural fill and backfill should be placed in maximum 12-inch loose lifts and compacted to 95 percent of the maximum dry density within a targeted two percent of the optimum moisture content as determined by ASTM D 1557 (Modified Proctor). Variations in moisture content may be acceptable subject to Dynamic Earth’s on-site geotechnical engineer’s approval if the contractor is able to achieve the necessary compaction. Dynamic Earth recommends using a smooth drum roller or sheepsfoot roller (where fine-grained soils are encountered) to compact subgrade soils beneath larger areas such as pavements or slabs. Hand operated vibratory jumping jacks and plate compactors should be used in confined excavations for foundations or utilities. Fill material compacted with relatively light weight equipment or in the static mode may require additional passes and/or the material may need to be placed in thinner, loose lifts. Structural Fill Testing: Before filling operations begin, representative samples of each proposed fill material (on-site and imported) should be collected. The samples should be tested to determine the maximum dry density, optimum moisture content, natural moisture content, gradation, and plasticity of the soil. These tests are needed for quality control during compaction and also to determine if the fill material is acceptable. The placement of all fill and backfill should be monitored by Dynamic Earth’s geotechnical engineer or technician to ensure that the specified material and lift thicknesses are properly installed. A sufficient number of in-place density tests should be performed during fill placement to ensure that the specified compaction is

t the specified material and lift thicknesses are properly installed. A sufficient number of in-place density tests should be performed during fill placement to ensure that the specified compaction is achieved throughout the height of the fill or backfill. 5.5 Preliminary Pavement Recommendations The on-site soils are preliminarily expected to be suitable for support of proposed pavements. Due to the reworked onsite material and moisture sensitivity of the on-site soils, at least partial overexcavation and replacement, re-compaction and/or subgrade stabilization should be expected, as detailed throughout this report. Depending on the overall subgrade conditions and weather conditions, more extensive mitigation efforts may be required. If required, a specific pavement section can be provided based on the results of a supplemental geotechnical investigation. SHI Builders 13 4266-99-001E

5.6 Preliminary Groundwater Considerations Indicators of seasonal high groundwater were encountered during this investigation as shallow as 1.4 feet below existing site grades. As such, groundwater control measures should be anticipated for this project, as detailed below. Permanent Groundwater Control: The need for permanent groundwater control measures should be evaluated along with the final site grading plans by the project’s structural engineer and architect as part of the building design. Waterproofing and permanent groundwater control measures are recommended along proposed foundation walls that will be located below the seasonal high groundwater level. In addition, under slab drains and sump pumps are recommended where the finished floor slab is near the groundwater elevation. Alternatively, the project’s structural engineer can include considerations for resisting the buoyant pressure (such as increasing the thickness of the floor slab) for the design of the floor slab. Temporary Groundwater Control: The contractor should anticipate the need for groundwater control within proposed excavations. Typically, excavations extending less than approximately two feet below the groundwater levels may be controlled by providing a sufficient number of sump pumps to draw down groundwater below the bottom of excavations. Deeper excavations that remain open for extended periods will require more extensive dewatering, possibly including installation of deep well points. The contractor should be responsible for providing adequate groundwater control so that proper installation of below grade structures can be accomplished. While the means of groundwater control will need to be determined by the contractor, the use of gravity fed sump pumps are typically suitable for dewatering of surface runoff, perched and infiltrating water. Surface water runoff must be controlled and diverted away from construction areas by grading and limiting the exposure of excavations to rainfall. 5.7 Preliminary Retaining Walls and Lateral Earth Pressure Recommendations Proposed retaining wall structures were not identified at this time; however, retaining wall structures may be proposed due to existing site topography and/or along the property lines (if necessary). Dynamic Earth presents the following preliminary design recommendations for use when designing proposed