Seismic Design Criteria Version 2

CALTRANSSEISMIC DESIGNCRITERIAVERSION 2.0State of CaliforniaDepartment of TransportationAPRIL 2019

TABLE OF REVISIONSiTABLE OF REVISIONS FROM SDC 1.7 TO SDC 2.0SDC 1.7SectionAllSectionsSDC 2.0SectionAllSectionsRevisionRearranged design provisions in a “Code and Commentary”formatIncluded new commentaries and referencesAdded Units to all empirical equationsDeleted Equations in Metric units1.1.1Changed scope of the SDC from “Ordinary Standard bridges” to“Ordinary Standard” and “Recovery Standard” bridgesMade major editorial revisions1.11.2.1,1.2.21.2Modified definition of an Ordinary Standard bridge, includingclassification of Pier walls and “Foundations in modified soil” asNonstandard featuresDeleted “Types of Components addressed in the SDC”1.2Added “Bridge Categories”1.2.2Added “Nonstandard Bridge Features”1.2.4Added “Recovery Bridge”1.2.5Added “Important Bridge”1.3Deleted “Bridge Systems”1.3Added “Seismic Performance Criteria”1.4Added “Design Philosophy”Added “Seismic Design Procedure Flowchart” (new Appendix A)AppendixA1.5Added “Procedure for Modifying the SDC”2.1Added “Definitions”2.2 and2.3Separated the listing of Notations and Acronyms/InitialismsAdded more “Notations” and “Acronyms/Initialisms”Clarified existing Notations3.1Added “Earthquake Resisting Elements” 2019 California Department of TransportationALL RIGHTS reserved.

iiSEISMIC DESIGN CRITERIA VERSION 2.0 APRIL 2019SDC 1.7SectionSDC 2.0Section3.2.1.1RevisionAdded “Safety Evaluation Earthquake” to the definition of DesignSpectrumDeleted “deterministic criterion” from the definition of DesignSpectrum for Safety Evaluation EarthquakeUpdated the online design tools for specification of DesignSpectrum3.2.1.2Added definition of Design Spectrum for Functional EvaluationEarthquake2.1.53.2.1.5Modified the use of Damping Ratios (ratios other than 5% torequire a PSDC)6.1.23.2.2Clarified Liquefaction hazard6.1.43.2.4Modified provisions for “Additional Seismic Hazards”3.2.33.3.3Added provisions for Grade 80 Steel (Properties and usagelimitations)3.2.7Deleted “Other Material Properties”5.6.1.13.4.2Deleted Figure for “Effective Stiffness of Cracked ReinforcedSections” and replaced it with equations for the relevant range ofaxial load ratios5.6.1.23.4.3Changed “Effective Moment of Inertia for Box GirderSuperstructures” to “Effective Moment of Inertia forSuperstructures and Cap Beams”Added provision for “effective moment of inertia for prestressedsections”5.6.23.4.4Clarified provision for “Torsional Moment of Inertia forSuperstructures”4.1.13.5.1Added “Global Displacement Criteria” for Recovery bridgesandClarified definitions of “frame/bent displacement capacity” and“frame/bent displacement demand,” and extended the definitionsto cover abutments and in-span hinges3.5.2Defined “Local Principal/Critical Axes”Made minor modification to Figure on “Global Force DeflectionRelationship”3.2.13.6Added “Load Factor”Changed Resistance factor for shear from 0.9 to 1.0 2019 California Department of TransportationALL RIGHTS reserved.

TABLE OF REVISIONSSDC 1.7Section4.5SDC 2.0Section4.2iiiRevisionAdded “Nonlinear Time History Analysis” as a standard analysismethodAdded “Equal Displacement Approximation” language for ESAand EDAAdded table: “Applicability of Methods for Displacement DemandAnalysis”4.5.14.2.1Provided equation for displacement demand using ESAAdded provision for determining the displacement demand ofsingle span bridges2.1.2.14.2.2andChanged “Tension” and “Compression” models to “Individualframe” and “Continuous global models”Deleted Figure on “Global Axis Definition”5.2.2Deleted Method I (100/30 % rule) for application andcombination of horizontal ground motionMade major editorial revisions4.2.3Added provisions for “Nonlinear Time History Analysis”4.3.1Added new provisions on abutment stiffness for Global models5.5Deleted “Simplified Analysis”5.44.3.2Clarified “Stand-Alone Models”5.4.14.3.2.1andandModified Figures: Transverse and Longitudinal Stand-AloneModels5.4.24.3.2.2Changed “abutment stiffness” provision for Stand-Alonelongitudinal model2.2.3 and2.2.44.4.1Clarified terms used in definition of displacement ductilitydemandAdded limiting values for displacement ductility demand forSCMs other than columnsDeleted displacement ductility demand values for pier walls4.24.4.3.1and4.4.3.2Added equations for Superstructure/Bent cap “Seismic Momentand Shear Demands”4.4.4Changed the factor for P-Delta equation from 0.20 to 0.25 2019 California Department of TransportationALL RIGHTS reserved.

ivSDC 1.7Section5.2.3SEISMIC DESIGN CRITERIA VERSION 2.0 APRIL 2019SDC 2.0Section5.2.2RevisionClarified definition and application of Inelastic Static AnalysisAdded provision for determining the displacement capacity ofsingle span bridgesModified the applicability of equations for Local DisplacementCapacityEditorial correction to Figure titled “Local Ductility Assessment”3.1.15.3.1Streamlined definition of seismic critical members (SCMs)Removed “Pier walls” and “Type II shafts in soft/liquefiable soil”as SCMs3.55.3.3Added provision for “Axial Load Limits”5.3.5Added “Confined Core”5.3.6.1Changed title from “Minimum Lateral Strength” to “MinimumFlexural Capacity”Clarified provision for “Minimum Flexural Capacity”3.3.15.3.6.2Added provision for Moment Curvature analysis of multi-columnbents in transverse direction to include overturning effects3.6.35.3.7.3Deleted equation for “Nominal Shear Reinforcement Capacity” ofPier walls3.8.25.3.8Section title changed from “Lateral Reinforcement ” to“Transverse Reinforcement ”5.3.8.1Added design provisions for transverse reinforcement5.3.8.2Added new provision for “Minimum volume of transversereinforcement” to replace the requirement for “Minimum localdisplacement ductility capacity”3.7.25.3.9.2Deleted equation for “Minimum Longitudinal Reinforcement” ofPier walls3.6.5.35.3.9.3Changed “maximum spacing of longitudinal bars in interlockingportion of SCMs” from 8 to 12 inchesCorrected dimension for Figure titled “Vertical Reinforcementwithin Interlocking Hoops”3.45.4.1Updated the list of Capacity Protected members (CPMs)4.3.25.4.4Added equations for Superstructure/Bent cap Seismic CapacityDeleted moment equilibrium equations for Superstructure andBent Cap Seismic Capacity 2019 California Department of TransportationALL RIGHTS reserved.

TABLE OF REVISIONSSDC 1.7Section3.8.6SDC 2.0Section5.4.56.2.26.1.1vRevisionModified the provision for transverse reinforcement for Type IIshaftsAdopted a new “Soil Classification”“Competent” soil now classified as “Class S1” soilAll non-Competent soils (Marginal, Poor, Soft, potentiallyliquefiable, and soil susceptible to lateral spreading) nowclassified as “Class S2”6.2.2.16.1.2Modified the characteristics of Class S1 (previously“Competent”) soil6.2.2.3Deleted “Marginal Soil”6.2.1Deleted “Foundation Performance”6.2.3Deleted “Foundation Design Criteria”6.2.2.17.7.1.67.7.1.7Added provisions for flexure and shear design of footingsDeleted “Effect of Large Capacity Piles on Footing Design”6.2.2.5Streamlined provisions for “Footing Stirrups”Modified annotations and added a Note to the Figure captioned:Footing Reinforcement – Fixed Column7.7.1.16.2.2.6Added provisions for “Spread Footings”6.2.3.1Modified the assumptions for design of pile foundations in classS1 soils6.2.3.2Added provision for shear resistance of piles in class S1 soil6.2.4.1Added provision for design of pile foundations in class S2 soil7.7.1.2ADeleted the provision allowing the simplified model forCompetent soil to be used for design of pile foundation in nonsoft/liquefiable marginal soil6.2.4.2Added “Comprehensive Foundation Design” for foundations inclass S2 soils (All foundations in class S2 soil to require acomprehensive design)7.7.1.2BDeleted “Lateral Capacity of Fixed Head Piles”7.7.1.2CDeleted “Passive Earth Resistance for Pile Caps in MarginalSoil”2.2.56.2.4.3Modified the provisions for “Scour and LiquefactionConsiderations” 2019 California Department of TransportationALL RIGHTS reserved.

viSDC 1.7Section2.2.4SEISMIC DESIGN CRITERIA VERSION 2.0 APRIL 2019SDC 2.0Section6.2.5.1RevisionMajor editorial revision to Types I and II shafts, including additionof new provisionsModified figure on “Shaft Definitions” and changed title to “ShaftTypes”6.2.6Added “Lateral Stability of Piles and Shafts”7.7.3.3Deleted “Shaft Diameter”7.7.3.4Deleted “Minimum Shaft Length”7.7.3.16.2.5.2Modified provisions for design of Type I shafts7.7.3.26.2.5.3Modified provisions for design of Type II shafts7.8.16.3.1.2Made a major revision to “Bilinear Model” for abutmentlongitudinal stiffness, including incorporation of a skew reductionfactor7.8.16.3.1.3Added an equation for “effective abutment longitudinal stiffnessadjusted for a displacement coefficient between 2 and 4”7.8.36.3.3Modified the Equation and Figure for abutment support lengthChanged terminology: “Abutment Seat Width” to “AbutmentSupport Length”7.8.46.3.4Modified Equations for abutment shear key force demand7.8.4.16.3.5Added a new provision for minimum development length ofHeaded bars used for shear key reinforcement6.3.5.1Added a new provision for Isolated Shear Key confinementreinforcement7.1.2Deleted “Balanced Stiffness” equations for Constant Widthframes7.1.1Modified definition of terms used for “Balanced Stiffness”Rearranged “Balanced Stiffness” equations7.1.27.1.3Rearranged “Balanced Frame Geometry” equationModified definition of terms used for “Balanced FrameGeometry”7.1.4Deleted “End Span Consideration”7.2.1.17.2.1.1Modified “Effective Superstructure Width” Figures A and B7.2.37.2.1.2Clarified and added new provisions for “Precast Girders”7.2.27.2.2Clarified and revised provisions for “Vertical Acceleration” 2019 California Department of TransportationALL RIGHTS reserved.

TABLE OF REVISIONSSDC 1.7Section7.2.5.4SDC 2.0Section7.2.3.1andviiRevisionModified the Equation and Figure for In-span hinge supportlength7.2.3.2Changed terminology from “Seat Width” to “Support Length”7.2.5.37.2.3.3Clarified and modified provisions for “Shear Key Requirementsin the Transverse Direction”7.2.77.2.3.5Modified provisions for “Pipe Seat Extenders”7.2.4Added “Superstructure Depth”7.2.8Added new design provisions and made editorial clarificationsDeleted “Equalizing Bolts”7.3.17.3.1Modified “Effective Width of Integral Bent Caps”7.4.17.4.1Clarified provision for “Joint Performance”7.4.5.17.4.5.2Clarified provisions for “T” and Knee Joint reinforcementandandModified figures for “Knee Joint Shear Reinforcement”7.4.5.17.4.5.37.57.5.1Added provision requiring PTFE spherical bearings to be used atall in-span hinges7.5.2Added provisions for “Seismic Expansion Joints”7.6.1Added new provisions for Columns (core geometry, framing,etc.)7.6.2Added provision for Column Dimensions for superstructures withdrop cap7.6.3Clarified provisions for Column Flares, including addition ofFigures for Horizontal and Vertical Flare Isolation7.6.57.6.67.6.7Deleted provisions for “Pier Wall”7.6.4Clarified equations for “Column Key Design”Added provision and commentary to account for momentgenerated by shear key steel8.1.18.2.1Added provisions on types and uses of “Reinforcing Bar Splices”8.2.2.1Clarified provisions for “No-Splice Zones” in SCMs 2019 California Department of TransportationALL RIGHTS reserved.