ER_1110-2-1806 Earthquake Design and Evaluation for Civil Works

_____________________________________________________________________

This engineer regulation supersedes ER 1110-2-1806, dated 31 July 1995

DEPARTMENT OF THE ARMY ER 1110-2-1806

U.S. Army Corps of Engineers

CECW-CE Washington, DC 20314-1000

Regulation

No. 1110-2-1806 31 May 2016

Engineering and Design

EARTHQUAKE DESIGN AND EVALUATION FOR CIVIL WORKS PROJECTS

TABLE OF CONTENTS

Page

1. Purpose …………………………………………………………………….................1

2. Applicability ..…………………………………………………………………………..1

3. Distribution Statement ………………………………………………………………..1

4. References ……………………………………………………………………………. 1

5. Policy ………………………………………………………………………………….. 1

6. General Provisions ………………………………………………………………...… 2

7. Design Earthquakes and Ground Motions ………………………………………… 5

8. Site Characterizations ……………………………………………………………….. 6

9. Concrete and Steel Structures and Substructures ……………………………….. 7

10. Embankments, Slopes and Soil Foundations …………………………………….. 9

11. Actions for New Projects …………………………………………………………….11

12. Actions for Existing Projects …………………………………………………………...…11

Appendix A – References A – 1

Appendix B – Hazard Potential Classification for Civil Works Projects B – 1

Appendix C – Seismic Hazard in USA C – 1

Appendix D – Seismic Study – Flow Chart D – 1

Appendix E – Progressive Seismic Analysis Requirements for Concrete E – 1

And Steel Hydraulic Structures

Appendix F – Design and Analysis Requirements for Seismic

Evaluation Reports F – 1

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DEPARTMENT OF THE ARMY ER 1110-2-1806

U.S. Army Corps of Engineers

CECW-CE Washington, DC 20314-1000

Regulation

No. 1110-2-1806 31 May 2016

Engineering and Design

EARTHQUAKE DESIGN AND EVALUATION FOR CIVIL WORKS PROJECTS

1. Purpose. This Engineer Regulation (ER) provides guidance for the seismic design,

analysis and evaluation of civil works projects. Additionally, this regulation establishes

design earthquakes with associated performance requirements to assure that all

features of civil works projects meet minimum seismic standards for serviceability and

safety. Seismic design standards for buildings and bridges for civil works projects are

also stated in this ER. In addition, all new designs and modifications to existing dams

and levees are to be designed to the additional safety standards in applicable engineer

regulations.

2. Applicability. This regulation is applicable to all HQUSACE elements and USACE

commands having responsibilities for the planning, design, analysis and construction of

civil works projects. The user of this ER is responsible for seeking opportunities to

incorporate the Environmental Operating Principles (EOP’s) wherever possible. A

listing of the EOP’s is available at:

http://www.usace.army.mil/Missions/Environmental/EnvironmentalOperatingPrinciples.a

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3. Distribution Statement. This document is approved for public release; distribution is

unlimited.

4. References. References are listed in Appendix A.

5. Policy. The seismic design of new projects and the seismic evaluation or

reevaluation of existing projects must be accomplished in accordance with this

regulation. This regulation applies to all projects that have the potential to malfunction

or fail during or following seismic events and cause hazardous conditions related to loss

of human life, appreciable property damage, disruption of lifeline services or

unacceptable environmental consequences. The effort required to perform these

seismic studies can vary greatly. The scope of each seismic study shall be focused on

assessment of ground motions, site characterization, structural response, functional

consequences and potential hazards in a consistent, well-integrated, and cost-effective

effort that will provide a high degree of confidence in the final conclusions. The

performance of operating equipment and utility lines can be as important as the

performance of the structural and geotechnical features of a project. When justifying

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circumstances exist, requests for a waiver from this policy shall be submitted by the

District Commander through the Division Commander to HQUSACE (CECW-CE).

Risk evaluation processes and tolerable risk guidelines for the evaluation or re-

evaluation of existing dams are provided in ER 1110-2-1156 “Safety of Dams – Policy

and Procedures”. The seismic design considerations and principles presented in this

regulation are meant to complement the seismic risk evaluation processes described in

ER 1110-2-1156. Evaluation of risk should be an integral part of any seismic design or

evaluation process.

6. General Provisions.

a. Project Hazard Potential. The hazard potential classification in Appendix B, Table

B-1 defines the consequences of project failure, based on the probable loss of human

life, the potential for economic losses, environmental damage and/or disruption to

lifelines. Critical features are the engineering structures, natural site conditions or

operating equipment and utilities at high hazard projects whose failure during or

immediately following an earthquake could result in loss of life due to inundation or

release of hazardous, toxic or radioactive materials. Such a loss of life could result

directly from failure or indirectly from flooding damage to a lifeline facility. Project

hazard potential should consider the population at risk, the downstream flood wave

depth and velocity and the probability of fatality of individuals within the affected

population. All other features are not critical features.

b. Design. Seismic design for new projects must include assessments of the

potential ground motions on project features to ensure acceptable performance during

and after design events. The level of design required to provide such performance is

dependent upon the seismic loadings, the complexity of the project, and the

consequences of losing project service or losing control of the pool. The analysis must

be performed in phases in order of increasing complexity. Continuity of the design

process is important throughout each phase. The plan of study for each phase of design

must be consistent with this regulation and with ER 1110-2-1150 “Engineering and

Design for Civil Works Projects”.

c. Evaluation. Evaluation or re-evaluation of existing project features differs from the

design of new features. The evaluation begins with a review of the project foundation

conditions, construction materials and the design of the project features. There must

also be an understanding of the construction practices used at the time the project was

built. Available information such as geological maps, boring logs, acceleration contour

maps, standard response spectra, structural and geotechnical analysis and studies,

construction photographs and as-built project records must be used to screen existing

project features to check for adequate seismic capacity. Detailed site explorations, site-

specific ground motion studies and structural analyses should be undertaken only for

projects in a High Seismic Hazard Region (HSHR) or in a Moderate Seismic Hazard

Region (MSHR) when seismic loading controls the design. The determination of

controlling load cases requires the evaluation of applied loads and the expected

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performance. Seismic loads are presumed to control the design when the risk

assessment (potential failure mode analysis) indicates or if the factors of safety for

seismic stability are lower than those computed for other load cases. The map in

Appendix C provides locations of the high, moderate and low seismic hazard regions.

d. Remediation. Upgrading existing project features to current seismic design

standards is generally expensive and shall be evaluated with a risk-informed process

that considers various factors, including but not limited to, expected loadings, expected

response and expected consequences. Expert judgment as well as appropriate linear

elastic and nonlinear analytical studies may be required to clearly justify the need for

remediation. Downstream nonstructural measures that reduce the project hazard must

be considered as an alternative to seismic remediation.

e. Project Team Concept. Earthquake design, analysis, evaluation or re-evaluation

of civil works projects requires close collaboration of an interdisciplinary team that

includes specialists in seismology, hydrology and hydraulics, geology, materials,

geotechnical and structural engineering. The team is responsible for establishing the

earthquake engineering requirements for the project, planning and executing the

seismological and engineering investigations and evaluating results. A senior structural

or geotechnical engineer must be responsible for leading the seismic design or

evaluation team. Technical experts shall be included on the team to provide guidance

on seismic policy, advise on earthquake engineering requirements, insure proper

evaluation of results and verify aspects of the seismological and engineering

investigations. This team must establish the scope of the entire seismic study early in

the design or evaluation process to ensure that resources are used efficiently and that

the seismotectonic, geologic, geotechnical and structural investigations are compatible

and complete.

f. Consulting Technical Experts. Seismic design or evaluation of civil works project

features is a highly complex engineering task that sometimes requires special expertise

and substantial engineering judgment in order to be effective. In many instances,

especially for large dams located in high seismic regions, the project team must

augment the in-house staff with technical experts to ensure independent review of the

methodology and results, to add credibility to the results and to help ensure public

acceptance of the conclusions. These experts may be from within USACE, other

government agencies, academia or the private sector. Technical experts must be

included in the early team planning sessions to assist in identifying the full scope of

work, selecting approaches and criteria, reviewing results and selecting the initial and

final seismic parameters. The experts must participate in meetings, provide memoranda

of concurrence and summary of advice.

g. Standard and Site-Specific Studies. Seismic studies must include the

seismotectonic, geologic, site, geotechnical and structural investigations required to

properly select the design ground motions, and to properly assess the response of the

foundation and structures to the earthquake events possible at the project site. Further

guidance on design/analysis requirements is provided in Appendices B-F.

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(1) Standard seismic studies are based on existing generic seismological studies,

available site data and information and simplified methods of evaluation. Generally,

standard studies use preliminary values of the ground motions obtained from published

and on-line United States Geological Survey (USGS) spectral acceleration maps. The

method to develop standard response spectra and the effective peak ground

acceleration (EPGA) for the project site is described in EM 1110-2-6053 “Earthquake

Design and Evaluation of Concrete Hydraulic Structures”. A preliminary structural

analysis and a simplified assessment of soil liquefaction and deformation will assess

how seismic loadings impact the design and will set the scope of any proposed site-

specific studies. Standard methods and data in the referenced guidance are useful for

preliminary and screening investigations in all seismicity regions, and may be

satisfactory for final design or evaluation in a low seismic hazard region or in some

moderate seismic hazard regions. The seismic-study flowchart describing the process is

provided in Appendix D.

(2) Site-specific studies use the actual site and structural conditions to evaluate the

project hazards and the response of the project features to seismic loading. Detailed

field exploration and testing programs must be carefully planned and executed.

Geologic studies should characterize the site, describe the seismotectonic province and

investigate all seismic sources that can affect the site. Seismologic investigations

should describe the earthquake history, earthquake recurrence relationship and strong-

motion records to be used in design or evaluation. Special emphasis should be placed

on identifying all geological, seismological and geotechnical parameters necessary for

the design and for determining the response of the foundations and structures.

Structural investigations should accurately account for all relevant factors that affect the

seismic hazard at the specific site and the actual dynamic behavior of the structure,

including damping and ductility characteristics of the structural systems. Geotechnical

investigations should assess the types and spatial distribution of foundation and

embankment material and the engineering properties of the soil and rock. Propagation

of the ground motion through the foundation and embankment, liquefaction potential of

foundation and embankment soils, stability of natural and artificial slopes and estimates

of deformations should also be evaluated. The final results of site-specific studies must

be used as the basis for making design or evaluation decisions and for the design of

any remedial measures. Site-specific studies shall be conducted for all projects located

in regions of high seismicity and moderate seismicity for which earthquake loading

controls the design. Detailed information on the development of site-specific design

response spectra can be found in EM 1110-2-6050 “Response Spectra and Seismic

Analysis for Concrete Hydraulic Structures”. EM 1110-2-6051 “Time-History Dynamic

Analysis of Concrete Hydraulic Structures” provides information on the development of

site-specific time-histories. There are two general approaches for conducting site-

specific seismic hazard analyses:

(a) Deterministic Seismic Hazard Analysis (DSHA). The DSHA approach uses the

known seismic sources that can affect the site along with the available historical seismic

and geological data to generate discrete, single-valued events or models of ground

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motion at the site. Typically, one or more earthquakes are specified by magnitude and

location with respect to the site. Usually, the earthquakes are assumed to occur at the

source closest to the site. The site ground motions are estimated deterministically, given

the magnitude, source-to-site distance and site conditions. DSHA is the standard

process used to estimate the seismic ground motion parameters for the Maximum

Credible Earthquake (MCE) and is typically conducted using a site-specific analysis.

(b) Probabilistic Seismic Hazard Analysis (PSHA). The PSHA approach uses the

elements of the DSHA and adds an assessment of the likelihood that ground motions

will occur during a specified time period. The probability (frequency of occurrence) of

different magnitude earthquakes on each significant seismic source and inherent

uncertainties are directly accounted for in the analysis. The results of a PSHA are used

to select the site ground motions based on the acceptable probability of exceedance

during the service life of the structure for a given return period.

constantly evolving. While new and better earthquake data are constantly being

compiled, instrumental recordings of seismic ground motions are still limited to about

100 years of information. This period of record is short, forcing extrapolation of results to

make PSHA estimates of ground motions for events with an Annual Chance

Exceedence (ACE) of less than 1E-02 (i.e., less frequent than once in 100 years). In

most studies, these extrapolations incorporate certain assumptions about “expected

value” trends and associated variance distributions that might not be accurate and in

many cases may be overly conservative. For example, the earth’s crust may not be

capable of transmitting accelerations estimated from extrapolation, thus overstating

expected shaking. This means that PSHA estimates of ground motion parameters may

be much larger than DSHA estimates for events with similar ACEs, even when the

PSHA uses the same seismic source and attenuation information.

7. Design Earthquakes and Ground Motions.

a. Maximum Credible Earthquake (MCE). The MCE is defined as the largest

earthquake that can reasonably be expected to be generated by a specific source on

the basis of seismological and geological evidence. Since a project site may be

affected by earthquakes generated by various sources, each with its own fault

mechanism, maximum earthquake magnitude, and distance from the site, multiple

MCE’s may be defined for the site, each with its own characteristic ground-motion

parameters and spectral shape. The MCE is evaluated using DSHA methods informed

by results from a PSHA. Since different sources may result in differing spectral

characteristics, selection of “maximum” ground motion parameters may need to

consider different sources and magnitude events to represent the full range of possible

maximum loadings e.g., peak ground acceleration from one source may be higher than

from another, but reversed for 1s spectral acceleration values. Therefore, both sources

may need to be considered in analysis to assess the full range of potential “maximum”

loadings. There is no return period for the MCE.

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b. Maximum Design Earthquake (MDE). The MDE is the maximum level of ground

motion for which a structure is designed or evaluated. The associated performance

requirement is that the project performs without loss of life or catastrophic failure (such

as an uncontrolled release of a reservoir) although severe damage or economic loss

may be tolerated. For critical features, the MDE is the same as the MCE. For all other

features, the minimum MDE is an event with a 10% probability of exceedance in 100

years (average return period of 950 years) assessed using a PSHA informed by the

results of a site-specific DSHA. A shorter or longer return period for non-critical features

can be justified by the project team based on the Hazard Potential Classification for Civil

Works Projects in Appendix B, Table B-1. A project with a low hazard potential

classification may consider return periods less than 950 years, while projects with a

significant or high hazard potential classification may consider longer return periods.

The MDE can be characterized as a deterministic or probabilistic event.

c. Operating Basis Earthquake (OBE). The OBE is an earthquake that can

reasonably be expected to occur within the service life of the project, typically a 50%

probability of exceedance in 100 years (average return period of 144 years) assessed

using a PSHA informed by the results of a site-specific DSHA. The associated

performance requirement is that the project functions with little or no damage and

without interruption of function. The purpose of the OBE is to protect against economic

losses from damage or loss of service, therefore, alternative choices of return periods

for the OBE may be based on economic considerations.

d. Estimating OBE and MDE Ground Motions. Estimates are usually made in two

phases. The first estimates are used as a starting point for the study and shall be

obtained from USGS spectral acceleration maps. The method to develop standard

response spectra and effective peak ground acceleration for the required probability of

exceedance (return period) for OBE and MDE is described in EM 1110-2-6053,

Appendices B and C. Site-specific studies in accordance with paragraph 6g(2) are

often required for selecting the final estimates of OBE and MDE ground motions. Both

DSHA and PSHA approaches are appropriate. Combining the results of deterministic

and probabilistic analyses is often an effective approach for selecting MDE ground

motions. Typical results of a probabilistic analysis include a hazard curve and an equal

hazard spectrum, which relate the level of ground motion to an annual frequency of

exceedance or return period. This information can be used to complement the

deterministic analysis by removing from consideration seismic sources that appear

unreasonable because of low frequencies of occurrence, by justifying median or

median-plus-standard deviation estimates of deterministic ground motion, or by

ensuring consistency of MDE ground motions with a performance goal.

8. Site Characterizations.

a. Site Studies. The two primary concerns in the site characterization for a project

are the effects of the ground motion on the site (such as loss of strength in foundation

materials and instability of natural slopes), and the effects of soil strata and topographic

conditions (basin effects, or ray path focus). These can influence propagation of the

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specified ground motion from a rock outcrop to a particular project feature. The

objective of a site characterization study is to obtain all of the data on the site conditions

that are required to design or to operate a project safely. The relevant site conditions

shall include the topographic and hydrologic conditions, the nature and extent of

foundation materials, the embankment, the natural slopes, the structures at the site and

the physical and dynamic engineering properties (such as modulus, damping, density,

and cyclic strain softening) of these materials. The site characterization shall be of a

progressive nature starting with information from available sources on the geology,

seismicity, and project features. A description of the site shall include geology and

seismicity (such as known faulting in the region, seismic history, and prior seismic

evaluations in the vicinity), and a review of the construction history and of any data

related to the project features at or proposed for the site.

b. New Projects. For new projects, field exploration and material testing programs

shall be developed to identify the stratigraphy and the physical and engineering

properties of the foundation materials at the project features. Prior field investigations in

the project area shall be evaluated to provide additional information.

c. Existing Projects. For evaluation or re-evaluation of existing projects, new field

investigations may be required where available data are insufficient.

9. Concrete and Steel Structures and Substructures.

a. Role of Structural Engineers. Methods for seismic studies/designs vary greatly

with the type of structure or substructure. Structural engineers shall be involved in the

selection of ground motions from the earliest stages of a study. Their understanding of

the ground motions in the form of peak ground acceleration, response spectra, and time

histories will be used in the structural analysis as it proceeds through progressively

more sophisticated stages as needed to reach definitive conclusions and make sound

decisions. Dynamic characteristics are important when selecting design events to

assure adequate demand levels in the period range of interest (i.e., near the natural

period of the structure). The structural engineer will establish how response spectra and

time-histories from standard and site-specific studies will be used in the structural

investigations. This progression is related to the level of accuracy or sophistication

required by the model and to address inherent uncertainties.

b. Design Standards for Buildings and Bridges. New building designs and upgrades

to existing buildings must be in accordance with the requirements of the 2012 Edition of

the International Building Code. Bridges on civil works projects shall be designed in

accordance with the American Association of State Highway Transportation Officials

(AASHTO) and state design standards, and evaluated in accordance with Federal

Highway Administration (FHWA) and state design standards.

c. Design Requirements for Concrete and Steel Hydraulic Structures. Seismic

design requirements for concrete and steel hydraulic structures (CSHS) are provided in

EM 1110-2-2104 “Strength Design for Reinforced Concrete Hydraulic Structures”, and

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EM 1110-2-6053 “Earthquake Design and Evaluation of Concrete Hydraulic Structures”.

It is noted that in ETL 1110-2-584, “Design of Hydraulic Steel Structures”, earthquake

loading required for design is currently limited to the operating basis earthquake (OBE)

only; this part of the ETL is under consideration for revision by USACE. Design of CSHS

must also be in accordance with all applicable references listed in Appendix A. Visual

inspections should also be performed of hydraulic steel structures after an unusual

earthquake, in accordance with EM 1110-2-6054, “Inspection, Evaluation, and Repair of

Hydraulic Steel Structures”. Such an inspection would be considered a “Special

Inspection” in accordance with ER 1110-2-8157, “Responsibility for Hydraulic Steel

Structures”.

d. Load Combinations. Design load combinations for CSHS must be in accordance

with EM 1110-2-2100 “Stability Analysis of Concrete Structures” and in accordance with

the referenced USACE design guidance for specific structures. In general, CSHS must

have adequate stability, strength, and serviceability to resist an OBE and MDE. The

structural and operating requirements are different for these two levels of earthquakes,

and either level may control the design or evaluation. The structure should essentially

respond elastically to the OBE event with no disruption to service. The structure may

be allowed to respond inelastically to the MDE event, which may result in significant

structural damage and limited disruption of services, but the structure must not collapse

or endanger lives. Economic considerations will be a factor in determining the

acceptable level of damage. In general, the OBE is an unusual loading condition, and

the MDE is an extreme loading condition.

e. Analysis Methods. Techniques used to evaluate the structural response to

earthquake ground motions include seismic coefficient methods, response spectrum

methods, and time-history methods. Using a seismic coefficient equal to 2/3 PGA or 2/3

EPGA is consistent with the stability analyses contained in EM 1110-2-2100. Details of

these methods of analysis can be found in the references listed in Appendix A (EM

1110-2-2100, EM 1110-2-6050, EM 1110-2-6051, and EM 1110-2-6053). Simplified

response spectrum analysis procedures are available for some types of CSHS, for

example, concrete gravity and arch dams (EM 1110-2-2200; EM 1110-2-2201) and

intake towers (EM 1110-2-2400). These methods utilize idealized cross sections and

make assumptions concerning the structure’s response to ground motions and its

interaction with the foundation and reservoir. The validity of these assumptions should

be carefully examined for each project prior to using any simplified analysis procedure.

In most cases, these methods will be sufficient for use in feasibility level studies. The

seismic coefficient method should not be used for final design of any structure where an

earthquake loading condition is the controlling load case. Final design for a project in

moderate or high seismic hazard regions shall use either response-spectrum or time-

history methods.

f. Input from Ground Motion Studies. Site-specific ground motion studies required in

accordance with paragraph 6g(2) at a minimum, should provide the magnitude,

duration, and site-specific values for the peak ground acceleration (PGA), peak ground

velocity (PGV), peak ground displacement (PGD), and the design response spectra and

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time-histories in both orthogonal horizontal directions and the vertical direction at the

ground surface or at a rock outcrop. Site-specific studies should also consider soil-

structure interaction effects which may influence ground motions at the base of the

structure.

g. Analysis Progression. An important aspect of the design, analysis, or evaluation

process is to develop an analytical model of the structure and substructure that can

adequately represent seismic behavior. The analysis process should be performed in

phases of increasing complexity beginning with simplified empirical procedures. These

procedures are based on satisfactory experience with similar types of structural

materials and systems and observations of failure due to strong ground motions. These

general requirements are outlined in Appendix E. Performing the analysis in phases

results in the analytical model providing realistic results and forms a logical basis for

decisions to revise the structural configuration and/or proceed to a more accurate

analysis method. The model used in the structural analysis can range from a simple

two-dimensional (2D) beam model to a sophisticated three-dimensional (3D) finite

element model. All three components of ground motion may be required to capture the

total system response. Dynamic analyses of most massive concrete structures will

usually require a model that includes interaction with the surrounding soil, rock, and

water. Differences in structural shapes and variations in foundation materials or ground

motion should be accounted for in evaluating the spatial variation in response between

points on large structures. The structural significance of mode shapes must be

considered, especially when evaluating the stresses using a response spectrum

analysis. The results of a finite element analysis of a reinforced concrete structure shall

be expressed in terms of moment, thrust, and shear. Areas where inelastic behavior is

anticipated shall be identified and the concrete confinement requirements stated. In

general, linear time-history methods applied to 2D or 3D models will provide the most

complete understanding of structural performance during an earthquake. If a design is

found to be inadequate using linear time-history methods of analysis, then nonlinear

time-history methods shall be considered. Such methods are beyond the scope of this

ER and must be conducted in consultation with CECW-CE.

h. Seismic Design Principles. It is important to incorporate sound seismic

engineering concepts in all aspects of the design or evaluation process. In all instances,

the design engineer shall minimize geometric irregularities in the structural

configuration, avoid abrupt variations in structural stiffness, and properly detail any

structural discontinuities to account for localized effects of stress concentrations.

Continuous load paths, load path redundancy, and ductility will improve performance

after extensive cracking and are important safe-guards against collapse.

10. Embankments, Slopes and Soil Foundations.

a. Role of Geologists, Seismologists, and Geotechnical Engineers. The seismic

evaluation and design of soil foundations, slopes, and embankments involves the

interaction of geologists, seismologists, and geotechnical engineers. The activities for

this effort can be grouped into four main areas: 1) field investigations, 2) site

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characterization, 3) numerical analyses, and 4) evaluation. It is essential that the

investigations and site characterization adequately portray the nature, extent, and in-

situ physical properties of the materials in the foundation, embankment, or slope being

investigated. The geologists, seismologists, and geotechnical engineers will select the

most effective methods to determine the uncertainties which must be dealt with correctly

and consistently so that the final result will be reliable and safe but not overly

conservative.

b. Embankments. Appropriate methods shall be used to analyze the liquefaction

potential and/or to estimate the deformations for embankments (e.g., dams, dikes,

levees that retain permanent pool), slopes, and foundation materials.

c. Slopes and Foundations. Slopes to be analyzed shall include natural, reservoir

rim, and other slopes, with or without structures, that have the potential to affect the

safety or function of the project. All foundation materials that support or affect project

features are to be analyzed for liquefaction. The results of investigations and data

review as described in paragraph 7 and the seismological evaluation will assess the

appropriate methods, including dynamic analysis, to be performed on the project.

d. Evaluations. Evaluation shall be performed on embankments, slopes, and/or

foundations that are susceptible to liquefaction or excessive deformation for all projects

located in high seismic hazard regions, along with those projects located in moderate

seismic hazard regions where materials susceptible to liquefaction or excessive

deformation are suspected. This evaluation and analysis shall also be performed

regardless of the seismic region location of the project, where capable faults are located

or recent earthquakes have occurred.

e. Design Features. Certain design features shall be incorporated, to the greatest

extent possible, into the foundation and embankment design regardless of the method

of seismic analysis. The details of these features shall be optimized based on the

results of the analysis. These design features include, but are not limited to the

following;

(1) Additional dam height to accommodate the loss of crest elevation due to

deformation, slumping, or fault displacement.

(2) Crest details that will minimize erosion in the event of overtopping.

(3) Wider transition and filter sections to resist cracking.

(4) Use of rounded or subrounded gravel and sand as filter material.

(5) Adequate permeability of the filter layers.

(6) Near-vertical drainage zones in the central portion of the embankment.

(7) Zoning of the embankment to minimize saturation of materials.

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(8) Wide, impeNious cores of plastic clay materials to accommodate deformation.

(9) Well-graded core and filter materials to ensure self healing

the event cracking

should occur.

(10)

Stabilization of reseNoir rim slopes to provide safety against large slides into the

reseNoir.

(11) Removal and replacement, in-situ densification, and/or drainage of foundation

materials susceptible to liquefaction.

(12)

Stabilization of slopes adjacent to operating facilities to prevent blockage from a

slide associated with the earthquake.

(13) Flaring of embankment sections at the abutment and concrete contacts.

11. Actions for New Projects.

For new projects, the phases of study required for the seismic analysis and design shall

accordance with ER 1110-2-1150, shall progress as described

Appendix E and

must be

compliance with SMART planning principles.

12. Actions for Existing Projects.

Seismic evaluation requirements are summarized

Appendix

The seismic

evaluation report must adequately explain any seismic deficiency. Also

outline of

additional investigations that are required to assess risk shall be assembled. Methods

to upgrade the project

meet current seismic criteria should also be listed. The

evaluation of existing structures should

done

accordance with ER 1110-2-1156

"Safety of Dams - Policy and Procedures". This report must be submitted for approval

HQUSACE, CECW-CE through the major subordinate command.

FOR THE COMMANDER:

6 Appendices

U_fi~

PETER HELMLINGER

COL,

Chief

Staff

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A-1

Appendix A

REFERENCES

ER 1110-2-1150 “Engineering and Design for Civil Works Projects”

ER 1110-2-1156 “Safety of Dams – Policy and Procedures”

ER 1110-2-8157, “Responsibility for Hydraulic Steel Structures”

EM 1110-2-2100 “Stability Analysis of Concrete Structures”

EM 1110-2-2201 “Arch Dam Design”

EM 1110-2-2104 “Strength Design for Reinforced Concrete Hydraulic Structures”

ETL 1110-2-584 “Design of Hydraulic Steel Structures”

EM 1110-2-2200 “Gravity Dam Design”

EM 1110-2-2400 “Structural Design and Evaluation of Outlet Works”

EM 1110-2-6050 “Response Spectra and Seismic Analysis for Concrete Hydraulic

Structures”

EM 1110-2-6051 “Time-History Dynamic Analysis of Concrete Hydraulic Structures”

EM 1110-2-6053 “Earthquake Design and Evaluation of Concrete Hydraulic Structures”

EM 1110-2-6054 “Inspection, Evaluation, and Repair of Hydraulic Steel Structures”

U.S. Geological Survey. 2014. National seismic hazard maps. Reston, VA: U.S.

Department of Interior.

http://earthquake.usgs.gov/hazards/products/conterminous/2014/HazardMap2014_lg.jpg

U.S. Geological Survey. 2009. Quaternary fault and fold database of the United States.

Reston, VA: United States Geological Survey.

http://earthquake.usgs.gov/hazards/qfaults/

American Association of State Highway and Transportation Officials (current edition).

AASHTO LRFD Bridge Design Specifications Washington, DC.

American Association of State Highway and Transportation Officials (current edition).

AASHTO Guide Specifications for LRFD Seismic Bridge Design. Washington, DC.

ER 1110-2-1806

31 May 16

A-2

Federal Highway Administration. 1995. Seismic retrofitting manual for highway bridges.

FHWA-RD-94-052. I. G. Buckle and I. M. Friedland, ed. McLean, VA.

Federal Highway Administration and Multidisciplinary Center for Earthquake

Engineering Research 2009. Seismic retrofitting manual for highway structures: Part 1 –

Bridges. FHWA-HRT-06-032. I. G. Buckle and I. M. Friedland, ed. McLean, VA.

Federal Highway Administration and Multidisciplinary Center for Earthquake

Engineering Research. 2009. Seismic retrofitting manual for highway structures: Part 2

– Retaining structures, slopes, tunnels, culverts and pavement. FHWA-HRT-05-067. I.

G. Buckle and I. M. Friedland, ed. McLean, VA.

International Building Code 2012 Edition (IBC 2012)

ER 1110-2-111 “USACE Bridge Safety Program”

EM 1110-2-1902 “Stability of Earth and Rock fill Dams”

EM 1110-2-2502 “Retaining and Flood Walls”

EM 1110-2-2504 “Design of Sheet Pile Walls”

EM 1110-2-2602 “Planning and Design of Navigation Locks”

EM 1110-2-2607 “Planning and Design of Navigation Dams”

EM 1110-2-2906 “Design of Pile Foundation”

EM 1110-2-3104 “Structural and Architectural Design of Pumping Stations”

American Society of Civil Engineers/Structural Engineering Institute. 2010. Minimum

design loads for buildings and other structures. ASCE/SEI 7-10.

American Society of Civil Engineers/Structural Engineering Institute. 2013. Seismic

rehabilitation of existing buildings. ASCE/SEI 41-13.

Ebeling, R. M. 1992. Introduction to the computation of response spectrum for

earthquake loading. Technical Report ITL-92-4. Vicksburg, MS: U.S. Army Engineer

Waterways Experiment Station.

Hynes-Griffin, M. E., and Franklin, A. G. 1984. Rationalizing the seismic coefficient

method. Miscellaneous Paper GL-84-13. Vicksburg, MS: U.S. Army Engineer

Waterways Experiment Station.

Idriss, I. M., and Archuleta, R. J. 2007. Evaluation of earthquake ground motions (Draft

06.5).

ER 1110-2-1806

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B-1

APPENDIX B

Table B-1

HAZARD POTENTIAL CLASSIFICATION

FOR CIVIL WORKS PROJECTS