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Geotechnical Services Division
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The Geotechnical Services
Division provides the full range of geotechnical engineering and
engineering geology services required to support the design,
construction, and maintenance needs of the state’s transportation
system.
The focus of these statewide
geotechnical services is to insure that the soil or rock beneath the
ground surface can support the loads and conditions placed on it by
these transportation facilities.
These geotechnical services include subsurface field
investigations, geologic site characterization, laboratory testing of
soil and rock, structure foundation and retaining wall design, soil
cut and fill stability design, rock slope design, unstable slope
management, unstable slope (e.g., rock fall, landslides, debris flow,
etc.) mitigation, material source (pits and quarries) evaluation,
long-term site monitoring for geotechnical engineering purposes,
support to Regional construction staff regarding geotechnical issues
and contractor claims, and support to Regional maintenance staff as
geotechnical problems (e.g., landslides, rock fall, earthquake or
flood damage, etc.) arise on transportation facilities throughout the
state.
WSDOT
is well known nationally for its geotechnical engineering and
engineering geology expertise, and provides a lead role in developing
and setting national public sector standards of practice for the
geotechnical profession. Our
staff are well trained and strongly motivated to develop cost
effective solutions for even the most difficult of geotechnical
problems. The Geotechnical Services Division consists of two main
sections, the Foundation Engineering Section and the Engineering
Geology Section. A
summary description of the sections and units that make up the
Geotechnical Services Division is as follows:
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Foundation
Engineering Section
This section has three main areas of responsibility
and it is divided into three separate units to handle
those areas. The units are:
Foundation
Engineering and Construction Unit - This unit is
focused on providing geotechnical engineering services for
the design and construction of structure foundations,
retaining walls, and soil cuts and fills.
Engineering
Support Unit - This unit provides drafting, computer
database and project schedule support for the entire
Geotechnical Services Division.
Laboratory
Testing Unit - This unit provides laboratory testing
services for the purpose of determining soil and rock
properties for geotechnical design, also for the entire
Geotechnical Services Division.
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Engineering
Geology Section
This section has three main areas of responsibility
and it is divided into three separate units to handle
those areas. The units are:
Engineering
Geology Design and Construction Unit - This unit is
focused on providing engineering geology services for the
design and construction of rock and soil slopes, unstable
slope mitigation and repair, geologic site
characterization, and geotechnical instrumentation reading
and data compilation.
Unstable
Slope Management Unit - This unit's responsibilities
include the management of over 2600 known unstable slopes
statewide, developing geotechnical conceptual designs for
slope stabilization and mitigation, cost estimating for
unstable slope projects, and completing a cost/benefit
analyses for those projects so they can be prioritized
based on benefit-cost and stabilized.
Field
Exploration Unit - This unit provides subsurface
drilling and soil/rock field testing services statewide
for the entire Geotechnical Services Division.
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Our Staff
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Key Contacts
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Geotechnical Design Manual (GDM)
This manual is primarily for geotechnical specialists
who wish to more fully understand WSDOT geotechnical
design policy to carry out various types of geotechnical
designs. For those who are not geotechnical
specialists, this manual is for those who wish to better
understand the roles and responsibilities of various
WSDOT offices regarding geotechnical design, design
policies that could affect the scope and cost of
geotechnical design services needed, and what to expect
with regard to products produced by the HQ Geotechnical
Division, the Region Materials Laboratories, and WSDOT
geotechnical consultants. For those who need to
implement proprietary walls in construction contracts,
this manual also provides approved plan details for all
pre-approved proprietary wall systems.
Geotechnical Design Manual M 46-03
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Requirements for a Geotechnical Investigation
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Useful
Links
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Infiltration
Ponds
Two
reports have been recently completed on the subject of
infiltration ponds.
The
first report covers the research that developed the new
design criteria.
The
second report is the design manual that will be useful to
those doing the actual sizing of the ponds in the
field.
WA-RD
578.1 Implementation of Infiltration Ponds Research
Joel Massmann. October 2003
WA-RD
578.2 A Design Manual for Sizing Infiltration Ponds
Joel Massmann. October 2003
- MSE Wall Design
This report provides the basis for the Simplified Method
specified in the AASHTO LRFD Bridge Design Specifications
(2007), and compares that method to other methods used in
the past such as the FHWA Structure Stiffness and Coherent
Gravity Methods. These methods are used to estimate
reinforcement loads for mechanically stabilized earth (MSE)
walls.
WA-RD 513.1 Development of the Simplified Method for
Internal Stability Design of Mechanically Stabilized Earth
Walls
Tony Allen, Barry Christopher, Victor Elias, and Jerry
DiMaggio, 2001
The following report presents a more accurate method of
estimating reinforcement loads for mechanically stabilized
earth (MSE) walls using the K-Stiffness Method.
WA-RD
522.2 Prediction of Reinforcement Loads in Reinforced Soil
Walls
Allen, T. M., and R. J. Bathurst. 2003.
- WSDOT Pile Driving Formula Research Report
Development of the WSDOT Pile Driving Formula and its
calibration for load and resistant factor design (LRFD).
WA-RD
610.1 Final Research Report
Allen, T.M. March 2005
- Analysis and Design of Wire Mesh/Cable Net Slope
Protection
Guidelines have been developed to
support the design of Wire Mesh and Cable Net Slope
Protection systems under a variety of loading conditions.
Specifically, it provides design guidance on site
suitability, characterizing external loads, fabric
selection, anchorage requirements, and system detailing.
WA-RD
612.1 Wire Mesh/Cable Net Slope Protection
B. Muhunthan et al. April 2005
WA-RD
612.2 Design Guidelines for Wire Mesh/Cable Net Slope Protection
B. Muhunthan et al. April 2005
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Long-Term Performance
of Geotextile Separators, Bucoda Test Site - Phase III
This research was Phase III
of field investigations carried out over 12 years at a
test section in southwest Washington in an effort to
quantify the contribution of geotextile separators to
the long-term performance of pavement sections.
B. Collins and R. Holtz,
October 2005
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Real Time Monitoring for Unstable Slope Evaluation and
Construction Control
This
PowerPoint presentation describes how real time
monitoring has been implemented on WSDOT projects to
investigate unstable slopes and to provide early warning
of performance problems for geotechnical structures
during construction.
- Background on Geotechnical Resistance Factors for LRFD
This NHI report presents the background needed to understand the basis of
the strength limit state resistance factors for geotechnical foundation design
provided in Section 10 of the AASHTO LRFD Bridge Design Specifications.
Development of downdrag load factors is also presented.
Development of Geotechnical Resistance Factors and Downdrag
Load Factors for LRFD Foundation Strength Limit State Design
FHWA-NHI-05-052
Allen, T.M. Feb. 2005In addition,
detailed step-by-step guidance on reliability theory
calibration of load and resistance factors for LRFD through
the TRB E-Circular website.
Calibration to Determine Load and Resistance Factors for
Geotechnical and Structural Design
TRB Circular E-C079
Allen, T.M., Nowak, A.S., and Bathurst, R.J. Sept. 2005
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