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Our Geotechnical team has over 100 years of combined experience. We specialize in transportation projects with bridges, walls, streets/roadways and rail. We also perform dam and flood control structure evaluations as well as slope and forensic evaluations across the state of Arizona.

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SR 303L, MC 85 to Van Buren Street


Ethos, as a subconsultant, conducted the final geotechnical investigation. Elements included 3 new overpass bridges; 51,000 lineal feet of retaining walls; pavement for 3 miles of mainline, ramp, frontage and crossroads; and a large stormwater retention basin. The field investigation included drilling by hollow stem, down-hole percussion and rotosonic methods approximately 130 borings to determine the ground support conditions for the above listed project elements. The traffic control included working alongside active traffic and within travel lanes involving multiple shoulder and lane closure setups including both daytime and nighttime work. 

Northern Parkway, El Mirage Road Overpass Final Design


Ethos supervised a geotechnical investigation for twin two-span overpass bridges that carry an elevated Northern Parkway over El Mirage Road. The project involved the bridges and approach and departure ramps. The bridges were constructed on deep, large diameter drilled shafts. Ethos assigned lab testing (performed by a subconsultant testing lab) and developed recommendations for the axial and lateral design of deep foundations as well as pavement design and other earthwork related items.

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SR 202L South Mountain Freeway


Ethos was part of a larger team that completed the largest design/build project in the history of ADOT. The project included 22 miles of new freeway with over 40 bridges, miles of retaining and sound walls, deep rock cuts, and considerable storm water conveyance. As part of the overall involvement of our company in this project, Keith Dahlen, PE was the lead geotechnical engineer for the project. Our team provided overall direction for the development of geotechnical recommendations for the design of bridge foundations, various types of retaining walls including MSE, soil nail and cantilever, and recommendations for the construction of embankments and drainage conveyances. Keith also provided guidance during construction for over-excavation of soft subgrade soils, the excavation of drilled shaft rock sockets and shop drawing reviews of MSE and soil nail retaining walls.

Cave Creek Road, Angela Drive to Marco Polo Road

City of Phoenix

Ethos, as a sub-consultant, performed geotechnical investigations to widen Cave Creek Road from Angela Drive to Marco Polo Road and reconstruct Contention Mine Road from Cave Creek Road to 26th Street.
Field work included lane closures for two borings along Contention Mine Road and eight borings along Cave Creek Road performed within City streets. Ethos also included recommendations for expansive soils, pavement, and retaining walls with shallow rock. 

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SR 202L, SR 101L to Val Vista Drive General-Purpose Lanes


Ethos completed geotechnical engineering design for this general-purpose lane widening project. This project included 8 miles of mainline pavement, 27 retaining walls, and widening of 4 bridge structures.  We drilled over 200 borings for the pavement, retaining walls, sound walls, and bridge widening elements. Our field program included the completion of auger borings along the freeway with shoulder and lane closures during daytime and nighttime hours. Drilling included coordinating multiple work crews to help expedite the field program. Recommendations included both shallow and deep foundations, rigid pavement design, and mitigation of soft/expansive soils.

Lake Havasu City Rotary Park Reservoir

Lake Havasu City

This park project included the subsurface investigation and design recommendations for a 350,000-gallon reinforced, cast-in-place concrete water storage reservoir. The tank was designed to be founded below grade in an area with shallow groundwater and support additional loads due to soil covering and truck loadings.


Lake Pleasant Heights-El Mirage Bridge over CAP Canal

City of Surprise

This project consisted of designing a new three-span, six-lane bridge over the CAP canal on a northward extension of El Mirage Road, north of Westland Road. Additionally, the bridge configuration accommodated an operations and maintenance road on the north side of the CAP Canal and a horse trail on the south side of the CAP Canal. 

Piestewa Peak Trailhead Phase II - Hopi & Mohave Area Picnic Design

City of Phoenix

The Piestewa Peak Trailhead project included improvements to trailheads along East Squaw Peak Drive within the Piestewa Peak Mountain Preserve. The multi-phased project increased public-parking spaces, facilitated traffic movement, added/restored ramadas and added restrooms at various locations. Ethos worked with Phoenix’s Parks & Recreation Department as a prime consultant for Phase II design, which included the Hopi and Mohave Trailheads. Ethos provided geotechnical investigations to assess support conditions for retaining walls, pavement, and shallow foundations, supported both in soil and rock.

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Dreamy Draw Mountain Preserve

City of Phoenix

Ethos served as a sub-consultant for final design providing geotechnical, civil, and structural engineering. The project reconfigured the existing parking lot to increase to 100 spaces for public parking, facilitated traffic movements, retrofitted two ramadas, and added a new restroom.
Ethos performed geotechnical investigations at the trailhead site to assess support conditions for pavements and foundations for retaining walls, as well as for slopes and other earthwork elements. 

ADOT Project Development On-Call


Ethos, as a sub-consultant, has completed more than 30 On-Call projects through ADOT's 2018 PDOC contract. Individual tasks involved evaluations of roadway, retaining walls, drainage conveyances and bridges, bridge replacements, bridge rehabilitations, pavement rehabilitations, pavement widening, pavement life extensions, and rumble strip additions associated with the state highway system. Geotechnical reports including drilled shaft and shallow foundations; and design recommendations including slope stability. 

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