2015 NEHRP Provisions

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Introduction to the

2014 NEHRP Recommended Seismic Provisions

David Bonneville Chair

2015 Provisions Update Committee

Building Seismic Safety Council Provision Update Committee

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2015 Provisions Update Committee Robert Bachman Philip Line David Bonneville (Chair) James Malley Kelly Cobeen Bonnie Manley C.B. Crouse Robert Pekelnicky Dan Dolan Rafael Sabelli John Gillengerten John Silva S.K. Ghosh Greg Soules Ron Hamburger Jason Thompson Jim Harris John Hooper Non-voting Technical Members: Gyimah Kasali Robert Hanson (FEMA) Dominic Kelly Jay Harris (NIST) Charlie Kircher Nico Luco (USGS)

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Building Seismic Safety Council Provisions Update Committee

2015 Provisions Support Mike Tong – FEMA Liaison Philip Schneider – BSSC Executive Director Bryan Bindrich – Degenkolb Chad Closs – Degenkolb Andrew Shuck - WJE

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NEHRP Provisions Part 1: Provisions Part 2: Commentary Part 3: Resource Papers

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Provisions Update Committee

Issue Teams PUC Members ASCE 7 SSC

Member Organizations

NEHRP Provisions - Proposal Development

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ASCE 7-10

PUC/Issue Team Proposal Groups

2009 Provisions

2015 Provisions

MO Ballot Packages

ASCE 7-16

2015 Provisions Development

A

E

B C D

F G

1 2 3 4


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2015 PUC Issue Teams FEMA P695/795 Ron Hamburger Performance Objectives Jim Harris, John Hooper Seismic Anchorage Kevin Moore NLRH Analysis Curt Haselton Diaphragm Design S.K. Ghosh, Kelly Cobeen Liquefaction/Site Factors Bob Bachman/C.B. Crouse Foundation Strength Martin Johnson Design Maps (USGS) Nico Luco Soil Structure Interaction Bob Pekelnicky Base Isolation & Damping Bob Pekelnicky, Ron Mayes MRS Analysis Jim Malley RWFD Design Dominic Kelly Simplified Analysis Bill Holmes, Jim Harris, Curt Haselton

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Issues Selected by the PUC based on the degree to which they affect or advance practice, or fix something Types of Issues: • Those related to seismic performance • Those that improve analysis/design provisions • Those that affect/change seismic demand

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Related to Seismic Performance: • Intent of Provisions – Performance Objectives (Harris) • Seismic Qualification using FEMA P695/P795 (Hamburger)

Related to Seismic Demand: • USGS Hazard Maps and NEHRP Design Maps (Luco) • New Site Soil Coefficients (Crouse) • Site Specific Design Requirements & Parameters (Kircher)

2015 Provisions Update Committee Major Topics

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Related to Analysis/Design: • Modal Response Spectrum Analysis (Malley) * • Nonlinear Response History Analysis (Haselton) • Diaphragm Analysis and Design (Ghosh) • Rigid Wall/Flexible Diaphragm Buildings (Kelly) • Strength-Based Foundation Design (Johnson) • Foundations on Liquefiable Sites (Bachman) • Base Isolation and Energy Dissipation (Button) • Soil-Structure Interaction (Pekelnicky) * • Simplified Seismic Design for SDC B (Hooper)

2015 Provisions Update Committee Major Topics

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The objectives of these provisions are to provide reasonable assurance of seismic performance that will: 1. Avoid serious injury and life loss due to

a. structural collapse, b. failure of nonstructural components or systems, c. release of hazardous materials

2. Avoid loss of function in critical or essential facilities, and 3. Reduce structural and nonstructural repair costs where

practical to do so.

Provisions Intent and Seismic Performance Considerations

(Provisions Section 1.1)

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Risk Category Collapse Given MCER Collapse in 50 Years

I ** ** II 10% 1%

III 5% Less than 1%

IV 2.5% Less than 1%

Provisions Intent

Collapse:

Other Performance Objectives: Nonstructural Failure Hazardous Materials Functionality of Essential Facilities Repair Costs

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Incorporation of FEMA P-695/P-795

Invokes FEMA P695 as a basis for justification of new seismic systems (Section 12.2.1.1 – Alternative Structural Systems)

Example: Cold Formed Steel Bolted Moment Frame

FEMA P-695 – Quantification of Building Seismic Performance Factors

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FEMA P-795 – Component Equivalency Method

Incorporation of FEMA P-695/P-795

Example: Simpson Steel Strong-Wall


Invokes FEMA P795 as a preferred means of justifying substitute components in a defined system (Section 12.2.1.1 – Alternative Structural Systems)

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Update of Risk-Targeted MCE Design Maps

Based on USGS update of national hazard maps (+/- 10-15% changes)

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Site Coefficients (Fa and Fv)

Modification of site factors (around since the 1990’s) to reflect NGA GMPE’s expressed at B-C boundary. Based on GM data set consisting of 1000’s of recordings.

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+20%

Site Specific Analysis Requirements

Require a site-specific for certain site classes and spectral values

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Modal Response Spectrum Analysis

Changes: • Scaling forces

and drifts • Modeling (3-D) • Combining modes

(addressing high frequency modes)

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Nonlinear Response History Analysis

GM Selection and Scaling

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Analysis and Modeling

Nonlinear Response History Analysis

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Diaphragm Analysis and Design

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Rigid Wall – Flexible Diaphragm Buildings

Examine and refine seismic design provisions and performance expectations for RWFD buildings – Part 3

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EQ motion

Overturning moment

Address structure/foundation and foundation/soil interfaces considering ultimate strength design and stiffness modeling

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Foundations on Liquefiable Sites

Address liquefaction and other site seismic soils-related issues to prevent collapse and quantify performance


Presenter

Presentation Notes

Typical damage in the Marina District following the 1989 LPE.

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Base Isolation Provisions

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Structures with Dampers (Chapter 18)

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Soil-Structure Interaction

Foundation Deformations Inertial Interaction Effects Radiation Damping Hysteric Damping Kinematic Effects Base Slab Averaging Embedment

Considerations:

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Simplified Provisions

Seismic Design Categories

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BaseShear

DesignMaps

SiteClass

SiteSpecific

MRS SSI

+/- +/- + +

-

Effects of Certain Changes on Seismic Demand

Base Shear

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Questions/Discussion

Documents

2015 NEHRP Provisions