Xiaoyi Koehn

Detail-oriented, organized and meticulous employee. Works at fast pace to meet tight deadlines. Enthusiastic team player ready to contribute to company success. Competent Engineering professional offering foundation in engineering project management and design. History of success in performing load and cost calculations and establishing clear parameters. Detail-oriented with strong knowledge of [Area of expertise] and [Software].

This park improvement project includes a new fishing pier and boat ramp for The City of Mountlake Terrace. The proposed pier is to extend much further into the lake than the existing pier for allowing anglers to access deeper waters. The new pier generates roughly 200 linear feet of fishable access. Ms. Koehn’s team devised an overwater study that was able to obtain the necessary geotechnical data using soft sediment probing and dynamic cone penetration testing instead of a floating barge, drill rig, or combustion engines (City ordinance), which resulted in a net saving for the City of over $80,000. The construction was completed very smoothly, and the pier is open for public use.

The school districted expanded by added mobile classrooms to six (6) campuses, all of which required geotechnical studies for foundation bearing support and management of stormwater runoff. Ms. Koehn worked with the general contractor to efficiently perform the pit infiltration testing within the proposed footprint of the infiltration galleries as construction equipment was mobilized from site to site. Ms. Koehn’s team was constrained by equipment availability, work hours for active school campuses, and budgetary considerations. The team was able to perform multiple infiltration test at the same time to execute the studies in the constrained time frame.

121 Boren – Seattle, WA

Ms. Koehn performed the geotechnical engineering services for the 47-story mixed-use high-rise tower with 7 levels of underground parking. The building foundation will be a mat foundation. The shoring system consisted of soldier piles with tieback anchors. Ms. Koehn also checked the calculation package for the temporary shoring design up to 55 feet below existing ground. Other responsibilities included assisting with the development of shoring drawings and response to permit review comment from the City of Seattle. Terracon was contracted to the owner for the shoring design and geotechnical services.

1120 John – Seattle, WA

Ms. Koehn performed the shoring submittal review for the new office building with five levels of below grade parking. The shoring system consisted of soldier piles with tieback anchors. The shoring system is required to limit deflection of the historic City Times Building facades that will be incorporated into the new structure. Ms. Koehn is currently performing the construction management for the shoring and geotechnical inspection. Construction started in 2022 with anticipated completion in later Winter 2023. Terracon was contracted to the owner (Onni Contracting, Inc) for the shoring design and geotechnical services.

Ms. Koehn performed the geotechnical services for multiple data centers including large footprint with substations, water tanks, infiltration ponds, retaining walls, and associated access roads and parking within large areas. Ms. Koehn conducted the subsurface exploration program including drilling, in-situ small polite infiltration tests and well infiltration tests, and in-situ electricity resistivity tests, and performed the geotechnical engineering services during preliminary phase and final phases.

15th NE North Affordable Housing– Seattle, WA

Ms. Koehn performed the geotechnical engineering services and is designing the shoring system consisting of cantilever soldier piles for the development of a seven to eight-story affordable housing apartment with one-level below grade parking. Geotechnical engineering recommendations provided concerned subsurface soil conditions, groundwater conditions, seismic considerations and liquefaction, ground improvement, earthwork, foundation design and construction, and excavation design. Terracon is contracted to the owner for the shoring design and geotechnical services.

12 Bellevue Way SE – Bellevue, WA

Ms. Koehn conducted the subsurface exploration program and performed the geotechnical engineering services for the development of an eight-story mixed-use residential building with up to two levels below grade parking. Geotechnical engineering recommendations provided concerned subsurface soil conditions, groundwater conditions, seismic considerations and liquefaction, ground improvement, earthwork, foundation design and construction, and excavation design. A temporary excavation between about 13 to 61 feet below ground surface will be required. The shoring system is under designed consisting of soldier piles with tiebacks and soil nails.

Mercer Island Mixed-Use – Mercer Island, WA

Ms. Koehn performed the geotechnical engineering services for the development of a three-story mixed-use building with up to two levels below grade parking. Geotechnical engineering recommendations provided concerned subsurface soil conditions, groundwater conditions, seismic considerations and liquefaction, ground improvement, earthwork, foundation design and construction, and excavation design. The foundations were recommended to be a mat foundation with ground improvement or deep foundations. The shoring system will consist of secant piles with tieback anchors.

WSDOT SR 202 Evans Creek & Patterson Creek Fish Passage – King County, WA

Ms. Koehn is conducting geotechnical analyses for foundations and settlement for the Patterson Creek culvert replacements that are a part of this design build project that will design and construct fish passage culvert replacements at Evans Creek, Patterson Creek, and two unnamed tributaries to Patterson Creek. The existing Evans Creek culvert is at the base of a 45-foot-high highway embankment. The replacement culvert will be a three-sided box culvert 25 feet wide and 154 feet long that will be replaced during two weekend highway closures. The other replacement culverts will range from 16 to 25 feet wide and will be four-sided box culverts constructed in very soft ground with a high groundwater table.

601 Dexter Office Building– Seattle, WA

Ms. Koehn designed the temporary shoring for the construction of the 11-story mixed-use building with three levels of below-grade parking. The development required shoring depths up to 47 feet and the area of the shoring was approximately 23,400 square feet. Other responsibilities included assisting with the development of shoring drawings and response to permit review comment from the City of Seattle. Terracon is contracted to the general contractor for shoring design services.