Geotechnical Evaluation of Landslide – Parker, Arizona

Excessive moisture within a weak, highly plastic clay-rich Tuff layer located near the base of a slope induced movement of the slope. Single story homes were located both at the crest and also near the base of the slope. . The homeower at the base of the slope engaged Ethos to perform a geotechnical investigation of the site and to develop mitigation measures to protect their home. Ethos completed the investigation which consisted of hollow stem auger test borings advanced into soft bedrock. A retaining wall supported on drilled shaft rock sockets was designed to protect the home. Ethos provided on-call supervision of the drilled shaft installations.

Hopi and Mohave Area Picnic Design – Phoenix, AZ (City of Phoenix)

Ethos is currently leading the design for two parking and picnic areas within the Piestewa Peak Mountain Area. As part of the overall involvment of our company in this project, our geotechnical team supervised the drilling of test borings at both trailhead sites to identify the depths of coarse-grained colluvial soils and depths to bedrock. This information, along with the results of laboratory testing, was used to develop recommendations for the design of pavements, standard cast-in-place and gabion retaining walls and permanent slopes. Foundation design recommendatoins were also developed for a restroom building.

Northern Parkway, El Mirage Road Overpass Final Design – Maricopa County, AZ (MCDOT)

Ethos supervised a geotechnical investigation for twin two-span bridges that will carry an elevated Northern Parkway over El Mirage Road.  The project involves the bridges, and approach and departure ramps.   The bridge will be 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 eartwork related items.

SR 202L South Mountain Freeway, Phoenix, AZ (ADOT)

Ethos is currently working on the largest project in the history of ADOT that provides 22 miles of new freeway. 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 walls, and recommendations for the construction of embankments and drainage conveyances.   Keith also provided guidance during construction for overexcavation of soft subgrade soils, the excavation of drilled shaft rock sockets and shop drawing reviews of MSE and soil-nail retaining walls.

Lake Havasu City Rotary Park Reservoir – Lake Havasu, AZ (Carollo Engineers)

Lake Havasu City contracted with Carollo Engineers to design a partially buried concrete water storage reservoir at a site located within Rotary Park, near the banks of the Colorado River. Our investigation included the advancement of down-hole hammer test borings to penetrate dense sands and gravels. The design was dependent on existing and anticipated future groundwater levels. The ADWR permitted borings each encountered groundwater at depths determined to be safe in terms of stucture support. We provided geotechnical recommendations for the tank, planned excavations, corrosion properties, and other earthwork considerations.

US 89, MP 526 Landslide Geotechnical Assessment, Near Bitter Springs, AZ (ADOT)

Keith Dahlen was Project Manager for the geologic/geotechnical characterization of a large (40 M ton) landslide that closed US 89 in February of 2013. Assessment included geologic mapping, test drilling and installation of 20 slope inclinometers to monitor landslide movement and provide data for the development of remedial design measures. Provided recommendations for mitigation of the slide area through extensive slope stability analyses and a preferred alternative for re-opening of the highway utilizing a 1M cubic yard buttress fill. Project awarded the Arizona ACEC 2015 Grand Choice Award and National 2016 AEG Project of the Year.