Bill Zietlow
Mr. Zietlow has worked in geotechnical engineering for 25 years and specializes in design of earth support systems for tunnels, shafts, road cuts, and temporary excavations such as soil nail, tieback, sheet pile, soldier pile, and micropile walls. He has also designed deep foundations and landslide stabilizations. He primarily provides design services for specialty contractors on design-build projects but has also provided geotechnical designs for public and private owners, primarily on transportation and utility works. He has design, construction observation, geotechnical investigation, and project management experience on a wide variety of projects and ground conditions across the Western and Midwestern United States. His responsibilities include engineering design, project management, and claim support services.
SOIL NAIL DESIGN
Mr. Zietlow’s experience in soil nailing includes geotechnical investigations specifically for soil nail walls, design of permanent soil nail retaining walls, temporary soil nail shoring walls, soil nail construction observation, and soil nail testing. Mr. Zietlow has been designing both temporary and permanent soil nail retaining walls for 22 years. He has designed well over 200 walls at over one million square feet of facing. He has designed soil nail walls in ground conditions ranging from strong colluvial granular soils to soft clays with low shear strength to intermediate geomaterials that graded from decomposed residual soil into weathered bedrock. He has designed permanent wall facing systems consisting of stained and sculpted shotcrete, modular concrete blocks, pre-cast panels, and cast-in-place panels.
SLOPE STABILIZATION
In work related to slope stability and landslide mitigation, Mr. Zietlow has planned and performed geotechnical investigations, designed slopes and active landslide stabilization systems, and observed construction of tiebacks, soldier piles, drilled shafts and other structural elements of landslide mitigation.
Relevant Projects
Soil Nail Walls, Excavation Support, Retaining Walls, Underpinning
East Asian Library, Berkeley, CA
Design Team Member
Designed temporary soil nail shoring in decomposed Franciscan Mélange, up to 25-ft tall, owner University of California, constructed 2005.
Mendocino Pass Landslide Mitigation, Glenn County, CA
Design Team Member
Designed stabilization tiebacks with individual CIP reaction panels for existing active landslide impeding Forest Road 162. Also performed geotechnical investigation and installed and monitored inclinometers, owner FHWA Central Federal Lands, constructed 2003.
Perris Valley Pipeline, Riverside, CA
Design Team Member
Designed temporary support of excavation for a pipeline installation. This included 33-ft deep sections supported with braced sheet piles in sand below the water table. Constructed in 2009.
West Border Station Pedestrian Underpass, Calexico, CA
Engineer of Record
The West Border Station pedestrian tunnel will connect a port of entry building to an administration building on the other side of double Union Pacific railway tracks at the US-Mexico border in Calexico, California. The General Services Administration (GSA) and Immigration and Customs Enforcement (ICE) underpass will be a 45-ft long 9 ft by 12 ft walkway installed via pipe canopy and supported with steel sets and shotcrete. Mr. Zietlow is the tunnel Engineer-of-Record. The tunnel design is currently in final permit review by the railroad, which has already approved the installation method. Construction is expected to be completed in 2024.
I-66 Widening, Sully, Virginia
Brierley Associates is part of the design-build team on the I-66 project outside of Washington, D.C. Mr. Zietlow designed 13 permanent soil nail walls to provide horizontal space for additional lanes. The walls are approximately 120,000 SF of face area. The biggest wall is nearly 40-ft high by 2,000-ft long. Designs were completed in 2020 and construction was completed in 2020 and 2021.
Elkhorn Lodge Soil Nail Wall, Estes Park, Colorado
Brierley Associates designed a 20-ft high permanent soil nail wall with a steep backslope in silty sand with gravel overlying weathered granite bedrock for GeoCraft Builders. The wall was constructed to make space on a slope for a new lodge. The final wall facing was 3700 SF of shotcrete and construction was completed in 2021.
144 Bunker Hill Lode Rd Soil Nail Wall, Breckinridge, Colorado
To make flat space on an existing slope adjacent to the Breckinridge ski area for two residential construction sites, Mr. Zietlow designed a permanent two-tiered soil nail wall for GeoCraft Builders. The wall was 20-ft high and was constructed in silty sand with gravel on a steep slope. To overcome close proximity to the property line with no easement for soil nails, one of the return walls was supported with micropiles. The final wall facing was 2600 SF of shotcrete and construction was completed in 2021.
South Cascade Ave. Soil Nail Retaining Wall, Colorado Springs, Colorado
As part of a project by the City of Colorado Springs to stabilize the banks of a creek prone to flooding, Brierley Associates was retained by GeoCraft Builders to design a 12-ft high permanent soil nail wall to replace a failing cantilever concrete wall in the side of a creek drainage below an existing home. The final wall facing was shotcrete, which had to be placed below scour depth to avoid undermining erosion during high water flow events. The wall was successfully completed in 2020.
C-470 Managed Lanes Soil Nail Retaining Walls, Jefferson County, Colorado
Brierley Associates was retained by Baerren Concrete Construction to design 21 permanent soil nail walls totaling 61,000 SF to enable the widening of C-470 in both directions between Santa Fe Drive and I-25. The walls were constructed in sand, clay, and Denver Formation claystone and sandstone, were up to 35-ft tall, and were faced with full-height precast concrete panels connected to the soil nails. Mr. Zietlow was the Engineer-of-Record. These walls were constructed between 2017 and 2020.
Coffey Place Soil Nail Retaining Wall, Snowmass Village, Colorado
Mr. Zietlow designed two permanent retaining walls for GeoCraft Builders consisting of a soil nails on the main walls and cantilever drilled shafts on the return walls along property lines with no easements. The walls were on two three adjacent lots to make space for three homes near the Aspen Ski Resort. The existing steep slopes consisted of residual clay overlying Mancos Shale. The wall final facing consisted of 7570 SF of shotcrete. The wall was successfully completed in 2019.
Clear Creek Crossing Soil Nail Wall, Wheatridge, Colorado
To create space to widen the on and off ramps from I-70 to the 32nd Ave. underpass by removing the existing slope pavement, Mr. Zietlow designed two permanent soil nail walls under the existing I-70 bridge abutments. The wall final facing consisted of 800 SF of shotcrete. The walls were successfully completed in 2019.
US 183 Soil Nail Walls, Austin, Texas
The Central Texas Regional Mobility Authority built a new tolled expressway on an eight-mile section of US 183 in Austin, Texas. Brierley Associates was retained by the design/build team to design seven permanent soil nail walls totaling 117,123 SF and Mr. Zietlow served as the lead designer. The walls typically retained clay residual soils from the shales in Taylor Group and varied in height from 12 ft to 32 ft. Most walls were constructed partially under overpass bridges, with the soil nails extending between the abutment piles. Each wall faced with precast concrete panels attached to the soil nail shotcrete facing. Construction was successfully completed in 2019 and 2020.
Siphon 1, Winter Park, Colorado
As part of Denver Water’s pipe replacement project for the siphon that takes water into the Moffat Tunnel, the aerial crossing outside of Winter Park was replaced with a larger diameter pipe. This work included a permanent soil nail wall on each side of the Fraser River to accommodate pier installation and to protect the riverbank slope from scour and erosion. Brierley Associates designed both walls, including one toed in the river channel, several feet below the existing channel bottom. Construction was completed in 2019.
School of Mines Parking Garage Soil Nail Retaining Wall, Golden, Colorado
To make room for a new on-campus parking garage, a 40-ft high soil nail wall was required to support the excavation into the toe of a slope in fill and residual clay overlying near-vertical sandstone and claystone bedrock, which were exposed in the excavation. Mr. Zietlow designed the 16,800-SF wall for GeoCraft Builders with a complex shape to support existing uphill structures, street, and surface parking lot. The 650-ft long wall was successfully completed in 2018.
Bangerter Highway and 11400 South Interchange Soil Nail Walls, Salt Lake City, Utah
Brierley Associates was retained by Nicholson Construction Company to design two parallel, permanent soil nail walls to support the 11400 South Overpass over the Bangerter Highway. The walls totaled approximately 43,000 SF and were up to 23-ft high. They retained highly variable lacustrian and alluvial soil consisting of clay, silty, sand, and gravel with cobbles. The final facing is a combination of cast-in-place concrete and shotcrete. Mr. Zietlow was the Engineer-of-Record and the walls were successfully constructed in 2017 and 2018.
Trinidad Slope Stabilization, Las Animas County, CO
Lead Designer and Engineer-of-Record
Brierley Associates investigated and designed a slope stabilization system that allowed reconstruction of a canyon roadway that was made impassible due to a 200-ft long landslide. Road cut geology includes sandstone, conglomerate, and shale. Upslope of the roadway were beds of near-vertically faced sandstone that range from 2- to 10-ft thick. Within the sandstone are interbeds of shale that weathers to an approximately 1:1 slope, which lends itself to the occurrence of frequent rockfalls that litter the roadway and lower slope section. Brierley developed a soil nail remedy based on an observational approach during installation of the soil nail wall. This method allowed adjustment of the soil nail wall bottom to below the slide plane.
I-235 Widening, Des Moines, IA
Design Team Member
Designed 50,000-SF of soldier pile tie back retaining walls 30-ft tall in glacial clay and silt with permanent shotcrete lagging and CIP facing, performed geotechnical investigation, installed piezometers and inclinometers, installed and tested sacrificial test anchors, logged soil borings and rock core, installed and monitored piezometers, developed Engineering Geology sheets, constructed 2003.
US 40 Highway Widening, Phase 3, Berthoud Pass, Empire, CO
Design Team Member
Designed soil nail and tieback uphill retaining walls, designed reinforced foundation for down hill MSE walls, produced construction drawings and project specifications, reviewed soil borings, rock core and piezometer data to develop Engineering Geology Sheets and design geologic conditions, owner Colorado DOT, constructed 2004 and 2005.
Tarnes Parking Lot Wall, Vail, CO
Design Team Member
Designed permanent soil nail wall supporting clay slope up to 37-ft tall, final shotcrete facing, owner Vail Resorts, constructed 2004.
Residential Retaining Walls, Boulder, CO
Design Team Member
Designed permanent soil nail, MSE and micropile retaining walls up to 25-ft tall, constructed 2004.
Fitzgerald’s Casino Expansion and Reholing Inn Rebuild, Black Hawk, CO
Design Engineer
Designed permanent soil nail wall in colluvium and decomposed granite up to 35-ft tall with stained shotcrete final facing, owner Fitzgerald’s Casino, constructed 2004. Observed excavation, soil nail installation and soil nail testing, evaluated soil nail test results for conformity to design assumptions.
120th Avenue Bridge Underpass Shoring, Thornton, CO
Design Team Member
Designed permanent soil nail walls supporting clay fill between bridge abutment piers, shotcrete and CIP facing, owner Colorado DOT, constructed 2005.
Walgreen’s Retaining Walls, Golden, CO
Design Team Member
Designed permanent soil nail walls supporting clay fill between bridge abutment piers, shotcrete and CIP facing, owner Colorado DOT, constructed 2005.
Riverside Parkway Bridge Replacement, Grand Junction, CO
Design Team Member
Designed permanent and temporary soil nail retaining walls supporting alluvial fill between bridge abutment piers, up to 25-ft tall, owner City of Grand Junction, constructed 2006 and 2007.
Cherry Creek Shotcrete Foundation Wall, Denver, CO
Design Team Member
Designed drilled shaft and permanent shotcrete panel foundation wall for one floor below grade commercial building. Constructed by WLH Construction 2007.
C-470 and Alameda Retaining Walls, Jefferson County, CO
Project Manager
Designed permanent soil nail single- and double-tier retaining walls to support high tension power line towers. Constructed by WLH Construction 2007.
222 Main Street Temporary Soil Nail Shoring and Micropile Underpinning, Salt Lake City, UT
Design Engineer
Designed approximately 21,000-SF of temporary soil nail shoring and micropile underpinning to support a 25-ft deep excavation. Designed and monitored settlement instrumentation including VW liquid level sensors, VW tilt meters, crack gages and optical survey prisms. Constructed by Nicholson Construction in late 2007 and 2008.
Pole Canyon Pipeline, Smoky Canyon Mine, Southeastern ID
Design Team Member
Designed the geotechnical aspects of approximately 12,000-LF of 30-in diameter HDPE storm pipe installation and lined infiltration basin. Owner J.R. Simplot, constructed by mine personnel summer 2007.
BNSF RR Snow Shed D Micropile Foundation, Essex, MT
Design Team Member
Designed micropiles in soil and bedrock for foundation retrofit of existing snow shed on L.S. 36. Constructed by Nicholson construction summer of 2008.
Kennecott Hoist House Shoring, Bingham Canyon Mine, UT
Project Manager
Designed approximately 3,800-SF of temporary soil nail shoring with shotcrete facing for a hoist house foundation up to 16-ft deep in sand and gravel, constructed in 2008.
George Bush Turnpike Soil Nail Shoring, Dallas, TX
Project Manager
Designed approximately 250,000-SF of temporary soil nail shoring up to 40-ft deep in clay soils. Constructed in 2008 and 2009.
Salt City Plaza, Salt Lake City, UT
Designed jet grout tangent piles with soil nail shoring for a 20-ft deep excavation in extremely soft clay and peat. Constructed in 2009.
Design Team Member
Twin Box Tunnels - Liberty University, Lynchburg, VA
ENR Mid-Atlantic Region Best Small Project 2014
ENR Mid-Atlantic Region Best Project Safety Award 2014
ACEC Virginia-Grand Award 2014
The project is located on the campus of Liberty University and consists of two, two-lane, 130-ft long vehicular tunnels were installed by box-tunnel jacking methods beneath three Norfolk Southern railway lines where up to 32 trains including AMTRAK pass through each day. The two vehicular tunnels now provide access to Liberty University from Ward Road at the intersection with Harvard Street. Elements of this project include: installation of temporary excavation support systems to excavate the launching and receiving areas; installation of geotechnical instrumentation to monitor ground deformations; installation of spiling to control ground loss at the heading and mitigate deformation of the railways; installation of conduits through the embankment to protect post-tensioning tendons to facilitate the jacking operation; construction of a reinforced concrete launching pad; construction of a reaction block and a stable working surface at the receiving area; construction of two, 130-ft long concrete tunnel boxes, including a cutting shield, at the launching area; and jacking the two tunnel boxes to the final location. Mr. Zietlow performed global stability analysis and designed soil nail walls.
Eagle P3 Soil Nail Walls, Denver, CO
Project Manager
Designed three permanent soil nail retaining walls for the new light rail line from downtown Denver to Denver International Airport. The wall supporting I-25 was approximately 9,400-SF and 27-ft high in clay fill, the wall supporting I-70 was approximately 6,500-SF and 27-ft high in clay fill, and the wall near Pecos Street supporting Union Pacific RR tracks was approximately 4,200-SF up to 25-ft high in sand fill. Constructed 2012 and 2013.
Whitehead Creek Storm Water Separation Shafts SOE, Kansas City, MO
Principal-in-Charge and Project Manager
Designed 28-ft diameter, 22-ft deep tunnel shafts in extremely soft clay, supported with liner plates and ring beams. Constructed in 2012 and 2013.
Questa Mine Retaining Wall, Questa, NM
Project Manager
Designed 30,000-SF of permanent soil nail wall up to 47-ft high with hollow bar soil nails in sand and gravel and decomposed bedrock.
Blue River Tunnel, Kansas City, KS
Components of the Blue River Interceptor include six tunnel reaches of 72-in diameter amounting to about 2,780-ft and two reaches of 48-in diameter tunnel that total 1,120-feet. Ground conditions within the tunnel envelopes consists of alluvium that exhibited squeezing behavior and sedimentary rock classified as shale, limestone and sandstone. Mixed face conditions were anticipated along most of the tunnel alignments. Tunnel depths ranged from 8- to 35-feet. Brierley Associates was retained by tunnel contractor SJ Louis to provide construction engineering submittals for shaft design and temporary ground support.
Mr. Zietlow was responsible for the design of 10 tunnel shafts up to 35-ft deep supported with braced trench boxes.
Publications
- “Excessive Deflection of a Temporary Soil Nail Wall in Coarse Alluvium and Granular Fill”, Zietlow, B., 62nd Annual University of Minnesota Geotechnical Engineering Conference Proceedings, 2014.
- Design of Geo-Structures, Colorado School of Mines Shotcrete Short Course, 2014.
- “Settlement Monitoring of a Building Underpinned With Micropiles and Soil Nails”, Zietlow, B., Lange, C., and Hammer, J., 33rd Annual Deep Foundations Institute Conference Proceedings, 2008.
- “Case History: Micropile Use for Temporary Excavation Support”, Macklin, P., Berger, D., Zietlow, B., Herring, W. and Cullen, J., Geotechnical Special Publication “Drilled Shafts, Micropiling, Deep Mixing, Remedial Methods, and Specialty Foundation Systems”, ASCE Publication No. 124, pp. 653-661, 2004.
