1502 WALL ST IMAGINE CHILDRENS MUSEUM Geotech Report 2022-10-25

Imagine Children's Museum Building Addition Revised Geotechnical Engineering Report Everett, Washington Project and Site Conditions The project site includes the existing Imagine Children's Museum which is located on the northwest corner of the city block bordered by Hoyt Avenue on the west and Wall Street on the north with a physical address of 1502 Wall Street. An alley borders the site on the east and a parking lot exists to the south of the existing building. The existing museum includes two stories and a basement encompassing 39,426 square feet. Based on aerial photography, it appears that the current rooftop is used as an outdoor play and parking area. An apparent storage container is located near the southwest corner of the existing building. The proposed expansion will include four new building stories above grade totaling 49,507 square feet. The addition will have an approximate 9,000-square-foot building footprint and will be constructed to the south of the existing building. Part of the expansion will include removal and replacement of the southern 25 feet of the existing building. No below-grade structures are currently planned as part of the expansion. The proposed addition will include 30-foot spans between columns with 60-foot spans at upper floor transfer girders. Live floor loads will range from 100 to 125 pounds per square foot (psf). The expansion site is relatively flat, with overall vertical relief of less than 5 feet. The building addition area was paved for use as a parking lot at the time of our 2007 exploration program. Existing paving included predominantly asphalt concrete paving (ACP), which was observed to be on the order of 1.5 inches thick at the exploration boring locations within the building addition footprint. 3.0 SUBSURFACE EXPLORATION Our 2007 field study included drilling seven exploration borings throughout the central portion of the city block. The exploration logs labeled EB-2 and EB-3 were completed within the proposed building addition footprint and have been included on Figure 2 of this report. The various types of sediments, as well as the depths where characteristics of the sediments changed, are indicated on the exploration logs presented in the Appendix. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. If changes occurred between sample intervals in our exploration borings, they were interpreted. Our explorations were approximately located in the field by measuring from known site features shown on the site plan provided to us. The conclusions and recommendations presented in this report are based on the two exploration borings completed within the proposed building footprint during the 2007 study. The number, locations, and depths of the explorations were completed within site and budget constraints at the time they were advanced. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions may sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of any variations between the field explorations may not become fully March 28,2019;Revised April 16,2019 ASSOCIATED EARTH SCIENCES,IN 5G8/Id-190104E001-3-Projects120190104\KEIWP age?' S ��