CALTRANS SEISMIC DESIGN CRITERIA

1 CALTRANS SEISMIC DESIGN CRITERIA VERSION State of California Department of Transportation APRIL 2019 TABLE OF REVISIONS 2019 California Department of Transportation ALL RIGHTS reserved. TABLE OF REVISIONS FROM SDC TO SDC SDC Section SDC Section Revision All Sections All Sections Rearranged DESIGN provisions in a Code and Commentary format Included new commentaries and references Added Units to all empirical equations Deleted Equations in Metric units 1. Changed scope of the SDC from Ordinary Standard bridges to Ordinary Standard and Recovery Standard bridges Made major editorial revisions , Modified definition of an Ordinary Standard bridge, including classification of Pier walls and Foundations in modified soil as Nonstandard features Deleted Types of Components addressed in the SDC Added Bridge Categories Added Nonstandard Bridge Features Added Recovery Bridge Added Important Bridge Deleted Bridge Systems Added SEISMIC Performance CRITERIA Added DESIGN Philosophy Added SEISMIC DESIGN Procedure Flowchart (new Appendix A)

2 Added Procedure for Modifying the SDC Added Definitions Appendix A and Separated the listing of Notations and Acronyms/Initialisms Added more Notations and Acronyms/Initialisms Clarified existing Notations ii SEISMIC DESIGN CRITERIA VERSION APRIL 2019 2019 California Department of Transportation ALL RIGHTS reserved. SDC Section SDC Section Revision Added Earthquake Resisting Elements Added Safety Evaluation Earthquake to the definition of DESIGN Spectrum Deleted deterministic criterion from the definition of DESIGN Spectrum for Safety Evaluation Earthquake Updated the online DESIGN tools for specification of DESIGN Spectrum Added definition of DESIGN Spectrum for Functional Evaluation Earthquake Modified the use of Damping Ratios (ratios other than 5% to require a PSDC) Clarified Liquefaction hazard Modified provisions for Additional SEISMIC Hazards Added provisions for Grade 80 Steel (Properties and usage limitations)

3 Deleted Other Material Properties Deleted Figure for Effective Stiffness of Cracked Reinforced Sections and replaced it with equations for the relevant range of axial load ratios Changed Effective Moment of Inertia for Box Girder Superstructures to Effective Moment of Inertia for Superstructures and Cap Beams Added provision for effective moment of inertia for prestressed sections Clarified provision for Torsional Moment of Inertia for Superstructures and Added Global Displacement CRITERIA for Recovery bridges Clarified definitions of frame/bent displacement capacity and frame/bent displacement demand, and extended the definitions to cover abutments and in-span hinges Defined Local Principal/Critical Axes Made minor modification to Figure on Global Force Deflection Relationship Added Load Factor Changed Resistance factor for shear from to TABLE OF REVISIONS iii 2019 California Department of Transportation ALL RIGHTS reserved.

4 SDC Section SDC Section Revision Added Nonlinear Time History Analysis as a standard analysis method Added Equal Displacement Approximation language for ESA and EDA Added table: Applicability of Methods for Displacement Demand Analysis Provided equation for displacement demand using ESA Added provision for determining the displacement demand of single span bridges and Changed Tension and Compression models to Individual frame and Continuous global models Deleted Figure on Global Axis Definition Deleted Method I (100/30 % rule) for application and combination of horizontal ground motion Made major editorial revisions Added provisions for Nonlinear Time History Analysis Added new provisions on abutment stiffness for Global models Deleted Simplified Analysis Clarified Stand-Alone Models and and Modified Figures.

5 Transverse and Longitudinal Stand-Alone Models Changed abutment stiffness provision for Stand-Alone longitudinal model and Clarified terms used in definition of displacement ductility demand Added limiting values for displacement ductility demand for SCMs other than columns Deleted displacement ductility demand values for pier walls and Added equations for Superstructure/Bent cap SEISMIC Moment and Shear Demands Changed the factor for P-Delta equation from to Clarified definition and application of Inelastic Static Analysis Added provision for determining the displacement capacity of single span bridges Modified the applicability of equations for Local Displacement Capacity Editorial correction to Figure titled Local Ductility Assessment Streamlined definition of SEISMIC critical members (SCMs) Removed Pier walls and Type II shafts in soft/liquefiable soil as SCMs iv SEISMIC DESIGN CRITERIA VERSION APRIL 2019 2019 California Department of Transportation ALL RIGHTS reserved.

6 SDC Section SDC Section Revision Added provision for Axial Load Limits Added Confined Core Changed title from Minimum Lateral Strength to Minimum Flexural Capacity Clarified provision for Minimum Flexural Capacity Added provision for Moment Curvature analysis of multi-column bents in transverse direction to include overturning effects Deleted equation for Nominal Shear reinforcement Capacity of Pier walls Section title changed from Lateral to Transverse Added DESIGN provisions for transverse reinforcement Added new provision for Minimum volume of transverse reinforcement to replace the requirement for Minimum local displacement ductility capacity Deleted equation for Minimum Longitudinal reinforcement of Pier walls Changed maximum spacing of longitudinal bars in interlocking portion of SCMs from 8 to 12 inches Corrected dimension for Figure titled Vertical reinforcement within Interlocking Hoops Updated the list of Capacity Protected members (CPMs) Added equations for Superstructure/Bent cap SEISMIC Capacity Deleted moment equilibrium equations for Superstructure and Bent Cap SEISMIC Capacity Modified the provision for transverse reinforcement for Type II shafts Adopted a new Soil Classification Competent soil now classified as Class S1 soil All non-Competent soils (Marginal, Poor, Soft, potentially liquefiable, and soil susceptible to lateral spreading)

7 Now classified as Class S2 Modified the characteristics of Class S1 (previously Competent ) soil Deleted Marginal Soil TABLE OF REVISIONS v 2019 California Department of Transportation ALL RIGHTS reserved. SDC Section SDC Section Revision Deleted Foundation Performance Deleted Foundation DESIGN CRITERIA Added provisions for flexure and shear DESIGN of footings Deleted Effect of Large Capacity Piles on Footing DESIGN Streamlined provisions for Footing Stirrups Modified annotations and added a Note to the Figure captioned: Footing reinforcement Fixed Column Added provisions for Spread Footings Modified the assumptions for DESIGN of pile foundations in class S1 soils Added provision for shear resistance of piles in class S1 soil Added provision for DESIGN of pile foundations in class S2 soil Deleted the provision allowing the simplified model for Competent soil to be used for DESIGN of pile foundation in non-soft/liquefiable marginal soil Added Comprehensive Foundation DESIGN for foundations in class S2 soils (All foundations in class S2 soil to require a comprehensive DESIGN )

8 Deleted Lateral Capacity of Fixed Head Piles Deleted Passive Earth Resistance for Pile Caps in Marginal Soil Modified the provisions for Scour and Liquefaction Considerations Major editorial revision to Types I and II shafts, including addition of new provisions Modified figure on Shaft Definitions and changed title to Shaft Types Added Lateral Stability of Piles and Shafts Deleted Shaft Diameter Deleted Minimum Shaft Length Modified provisions for DESIGN of Type I shafts Modified provisions for DESIGN of Type II shafts vi SEISMIC DESIGN CRITERIA VERSION APRIL 2019 2019 California Department of Transportation ALL RIGHTS reserved. SDC Section SDC Section Revision Made a major revision to Bilinear Model for abutment longitudinal stiffness, including incorporation of a skew reduction factor Added an equation for effective abutment longitudinal stiffness adjusted for a displacement coefficient between 2 and 4 Modified the Equation and Figure for abutment support length Changed terminology.

9 Abutment Seat Width to Abutment Support Length Modified Equations for abutment shear key force demand Added a new provision for minimum development length of Headed bars used for shear key reinforcement Added a new provision for Isolated Shear Key confinement reinforcement Deleted Balanced Stiffness equations for Constant Width frames Modified definition of terms used for Balanced Stiffness Rearranged Balanced Stiffness equations Rearranged Balanced Frame Geometry equation Modified definition of terms used for Balanced Frame Geometry Deleted End Span Consideration Modified Effective Superstructure Width Figures A and B Clarified and added new provisions for Precast Girders Clarified and revised provisions for Vertical Acceleration and Modified the Equation and Figure for In-span hinge support length Changed terminology from Seat Width to Support Length Added new DESIGN provisions and made editorial clarifications Clarified and modified provisions for Shear Key Requirements in the Transverse Direction Modified provisions for Pipe Seat Extenders Added Superstructure Depth Deleted Equalizing Bolts Modified Effective Width of Integral Bent Caps TABLE OF REVISIONS vii 2019 California Department of Transportation ALL RIGHTS reserved.

10 SDC Section SDC Section Revision Clarified provision for Joint Performance and and Clarified provisions for T and Knee Joint reinforcement Modified figures for Knee Joint Shear reinforcement Added provision requiring PTFE spherical bearings to be used at all in-span hinges Added provisions for SEISMIC Expansion Joints Added new provisions for Columns (core geometry, framing, etc.) Added provision for Column Dimensions for superstructures with drop cap Clarified provisions for Column Flares, including addition of Figures for Horizontal and Vertical Flare Isolation Deleted provisions