7800 EVERGREEN WAY HYUNDAI Wetland Report 2025-08-05

4.6.4.Asphalt-Treated Base If pavements are constructed during the wet season, consideration maybe given to covering the areas to be paved with asphalt -treated base (ATB) for protection. Light -duty pave mentareas should be surfaced with 3 inches of ATB, and heavy-duty pavement areas should be surfaced with 6 inches of ATB. ATB placed to support construction equipment and heavy construction loads should also be at least 6 inches thick, but should be evaluated by the contractor if thicker sections are needed. Prior to placement of the final pavement sections, we recommend the ATB surface be evaluated and areas of ATB pavement failure be removed, and the subgrade repaired. If ATB is used and is serviceable when final pavements are constructed, the CSBC can be eliminated, and the design PCC or asphalt concrete pavement thickness can be placed directly over the ATB. 4.7. Earthwork 4.7.1. Clearing and Site Preparation Construction of the building addition will require demolition of existing structures, asphalt pavement, curbs, and utilities. Concrete rubble and asphalt pavement retrieved from demolition activities may be recycled and reused as structural fill, otherwise it should be removed from the site along with other construction debris. Based on our explorations and site observations, the asphalt pavement is typically 2 to 3 inches thick. All existing utilities should be removed from the building addition footprintand be rerouted if needed. 4.7.2.Subgrade Preparation Prior to placing structural fill to support on -grade floor slabs, foundations or pavement, subgrade areas should be evaluated by probing and performing a proof -roll (as needed) to locate any soft soils. All unsuitable soils should be removed from below building addition foundation areas prior to the evaluation. The exposed foundation subgrade areas should be probed to determine the extent of loose fill or other unsuitable soils, while new slab -on -grade and pavement subgrade areas should be proof -rolled with a loaded dump truck or equivalent. If loose fill or pumping soils are observed they should be removed and replaced with structural fill. After completingthe evaluation, the subgrade areas should be recompacted to a firm condition, if possible. The degree of compaction that can be achieved will depend on when the construction is performed. If the work is performed during dry weather conditions, we recommend that all subgrade areas be recompacted to at least 95 percent of the MDD in accordance with the ASTM D 1557 test procedure (modified Proctor). If the work is performed during wet weather conditions, it may not be possible to re-compactthe subgrade to 95 percent of the MDD. In this case, we recommend that the subgrade be compacted to the extent possible without causing undue weaving or pumping of the subgrade soils. Subgrade disturbance or deterioration could occur if the subgrade is wet and cannot be dried. If the subgrade deteriorates during compaction, it may become necessary to modify the compaction criteria or methods. It may also be necessary to place crushed gravel to protect the floor slab subgrade areas during construction. GEOENGINEER� December6,2021 Page8 File No. 24 59-003-00