National Earthquake Hazards Reduction Program a research and - - PowerPoint PPT Presentation

national earthquake hazards reduction program

National Earthquake Hazards Reduction Program

… a research and implementation partnership

NIST Earthquake Engineering Program Overview

Advisory Committee on Earthquake Hazards Reduction

November 7 & 8, 2018

national earthquake hazards reduction program

Earthquake Engineering Group (2EG) Program Overview

Major Program Elements:

1.

Improved Building Code Provisions for Lateral Force-Resisting Structural Elements and Systems

2.

Performance-Based Seismic Engineering (PBSE) for New and Existing Buildings

3.

Tools & Guidelines for Improved Earthquake Engineering Practice

national earthquake hazards reduction program

Earthquake Engineering Group Philosophy

• To address three program elements through a combined effort

involving:

• Internal NIST research
• Task Orders issued to IDIQ contractor
• Research grants awarded via the Disaster Resilience Research Grant

Program Federal Funding Opportunity

national earthquake hazards reduction program

Earthquake Engineering Group (2EG)

Four Thrusts of the Program:

Thrust 1 Existing Buildings: to improve the evaluation and retrofit methods for existing buildings with the goal of reducing the collapse risk Thrust 2 EQ design in wind communities: to understand and improve the efficiency of building design and construction in regions with high wind and moderate seismic loads Thrust 3 Performance-based seismic design of new buildings: to improve the performance of new buildings through developing new or evaluating existing design criteria Thrust 4 NEHRP: to support the NEHRP statutory program as the lead agency

national earthquake hazards reduction program

Earthquake Engineering Group (2EG)

Thrust 1: Existing Buildings Thrust 2: EQ design in wind communities Thrust 3: Performance-based seismic design Thrust 4: NEHRP Pre-Northridge Panel Zones EBF Links FRP retrofitted systems Nonductile RC Columns Evaluation of buildings in Central and Eastern US Support of NCST Investigation Collapse Assessment of Buildings Quantification of Uncertainties Walls with High Strength Bars Steel Wide-Flange Beam Columns Energy-Based Collapse Assessment Immediate Occupancy

national earthquake hazards reduction program

Thrust 1: Existing Buildings

national earthquake hazards reduction program

Seismic Assessment and Retrofit of Pre-Northridge Earthquake Panel Zones in Steel Moment Frames (Underway)

• Problem: Panel zones in existing older pre-1990’s steel buildings

were not designed to current approaches and may be under capacity

• Combination of experiments and high-end analyses will be used to

study behavior to suggest ways to improve performance

• Results used to develop new assessment criteria for ASCE 41
• Provide guidance on retrofit approaches of panel zones for existing

buildings based on this research

Thrust 1

national earthquake hazards reduction program

Develop New Performance Assessment Criteria for EBF Links (Underway)

• Problem: Existing assessment criteria do not address loading history
• Establish a new performance-based assessment criteria capturing a component’s

dependence on loading history (the form of the cyclic response)

• Conduct a set of focused experimental tests and computer simulations
• n eccentrically braced frame link beams to develop these criteria
• Collaborating with CoE researcher Dr. Hussam Mahmoud at Colo State

Thrust 1

national earthquake hazards reduction program

Reliability of Fiber Reinforced (FR) Composite Systems in Resilient Infrastructure (Underway)

• Problem: FR composites have been used to repair, retrofit, and

strengthen infrastructure, BUT 1) to what extent the structural performance improves after application of FR composites 2) it is not clear how the performance of FR composites change over time.

• Who is involved? A collaborative effort between PMG, IMG, and

Earthquake group

• A workshop was held on May 15th 2018 to identify the research needs
• Currently, analyzing the workshop data
• Future research would focus on
• Develop test methods (inspection methods) to quantify the response
• Experimental studies on FRP retrofitted components
• Impact of degradation due to environmental factors

Thrust 1

national earthquake hazards reduction program

Collapse Performance Modeling of Nonductile Reinforced Concrete Columns (Underway)

• Problem: Older concrete columns pose a high risk of collapse
• n existing buildings. There is a need to improve the

simulation capabilities to capture the response of these columns

• The project has two phases: 1) developing a new column

model, 2) assess the collapse performance of older RC buildings

• The first phase is being conducted by a team from University
• f Texas (DRI awardee).
• The second phase will be conducted mainly at NIST (FY

2020).

• A workshop/webinar is being organized to present the
• ngoing effort to practicing engineers and city officials in LA.

Thrust 1

national earthquake hazards reduction program

Thrust 2: EQ design in wind communities

national earthquake hazards reduction program

Evaluation of low- and mid-rise buildings in Central and Eastern US (CEUS) (Underway)

• Problem: The effect of wind-dominant design on the seismic

performance of steel buildings built in the CEUS has not been formally quantified. Nor has the effect of not including seismic detailing on these buildings been evaluated.

• A suite of structural steel and concrete buildings is being

designed for multiple locations (e.g. Charleston, Memphis, and Long Island) for current and older building codes

• The seismic collapse performance of these buildings will be

evaluated

• The impact of detailing on the seismic performance of these

buildings will be identified.

• The outcome of this project could lead to potential construction

savings and improved performance in CEUS.

• Collaborative work with the CoE and the NCST investigation

Thrust 2

national earthquake hazards reduction program

Thrust 3: Performance-based seismic design

• f new buildings

national earthquake hazards reduction program

Seismic Implementation of High Strength Reinforcement Bars (HSRB) in Reinforced Concrete Structural Wall Systems (Underway)

• Wall and coupling beam components will be tested to generate vital

data to develop numerical models

• Numerical analyses will be conducted to compare the collapse risk of

structural wall buildings with regular and high-strength reinforcement

• New analytical tools and new building code provisions will be developed

Thrust 3

Wall reinforcement

• Problem: Reinforcement congestion in walls,

beams, columns and joints is a big problem. HSRB has the potential to expedite construction time and decrease construction costs.

• NIST sponsored work began a national effort to

adopt higher strength reinforcement as an option for earthquake-resistant construction

national earthquake hazards reduction program

Quantification of Material, Loading, and Modeling Uncertainties of Columns (Underway)

• Problem: The combined impact of modeling, material, and

loading uncertainty on the response of structures is less understood

• Develop a framework to combine three sources of uncertainty

to investigate the total uncertainty in the results at component and system levels for steel and concrete beam columns

• A blind prediction was conducted in Jan 2018. The second

phase is planned for 2019

100 200 300 400 500 600 0.05 0.1 0.15 0.2

Strain Stress

Material Modeling

• 1.5
• 1
• 0.5

0.5 1 1.5 2 4 6 8 10 12

Loading

+ +

Material+Modeling+ Loading Uncertainty Loading Uncertainty ?

Thrust 3

Strain

national earthquake hazards reduction program

Collapse Assessment of Buildings under Seismic Loading (Underway)

• Problem: No clear understanding of the relationship between

standards for new buildings and existing buildings

• Previous work has indicated the standard for existing buildings is

conservative

• Building’s collapse performance is assumed but not verified
• Determine the probability of collapse of a suite of steel

buildings by using a series of increasingly severe ground motions

• Investigate sensitivity of modeling and analysis assumptions
• Advocate for changes to ASCE 41 (or 7) based on findings
• Results suggest buildings have probability of collapse less than 10%, and confirm ASCE 41

assessment is conservative

Thrust 3

….

24 frames

(3 heights × 2 design procedures × 4 systems)

• 0.4
• 0.2

× scale factor

national earthquake hazards reduction program

Stability of Steel Wide-Flange Beam Columns in Seismic Loading (Underway)

• Problem: NIST GCR 11-917-13 identified multiple problems in

terms of design and modeling of deep, slender wide-flange steel columns, including limited test data, and the small scale of the prior tests

• The outcome of this project will assist designers in

characterizing the earthquake behavior of these components

Thrust 3

• 46 full-scale columns have been tested in

two phases at UCSD

• The second phase was conducted in 2018

to address a wider range of parameters and the repeatability/uncertainty of results

• The final report of the project will be published in 2019.
• The experimental results will be use to evaluate existing design

requirements to identify the potential need for change.

national earthquake hazards reduction program

Energy-Based Collapse Assessment of Framed Structures (New)

• Problem: Structural collapse in

PBSD is commonly defined as a function of drift ratios, and not depends on the loading history

• Develop an analytical tool to assess

structural performance and identify structural collapse using an energy- based approach

• Establish a new generation of

performance-based assessment criteria capturing a component’s dependence on loading history

• Provide results used to develop new

assessment criteria for ASCE 41

Thrust 3 Energy Demand from Simulations

ED1 ED2 ED3 ED4 ED5 ED7 ED9 ED6 ED8 ED10 ED23 ED25 ED27 ED24 ED26 ED28

Earthquake

ED17 ED19 ED21 ED18 ED20 ED22 ED11 ED13 ED15 ED12 ED14 ED16

EC1 EC5 EC11 EC17

Energy Capacity from Published Component Testing

national earthquake hazards reduction program

FY2018 Immediate Occupancy Report - Completed

• Congressional mandate (FY2017): “current building codes often do

not provide the necessary protection against natural hazards”

• NIST directed to identify: [the] “engineering principles”, “research”,

and “implementation activities” needed for a new “safety building performance objective for commercial and residential properties”

• Stakeholder-driven process: steering committee & workshop with 80

subject matter experts from public and private sector

• Vision: communities, owners, and residents would benefit from buildings

that maintain structural integrity, a building envelope that is intact, and internal systems that continue to function after a natural hazard event, thereby avoiding lengthy and costly repairs or rebuilding, as well as the need for long term evacuation of building occupants.

Thrust 3

national earthquake hazards reduction program

FY2018 Immediate Occupancy Report - Completed Key Areas for Consideration:

• Building Design

(advances in engineering, design, or retrofit)

• Community

(role of buildings in context)

• Economic and Social (feasibility and impacts of improved performance)
• Acceptance and Adoption

(supporting effective implementation)

Report Takeaways:

• Focus on buildings alone will not produce IO performance
• Social, economic, and community considerations should inform

desired building performance

• Developing performance criteria for buildings requires significant

stakeholder input

• “plan for a plan” would need significant additional

development to move forward

Thrust 3

national earthquake hazards reduction program

Updates on other Projects

• Performance-Based Seismic Engineering: Benchmarking of

Building Evaluation Methodologies, continuing

• Looking at damaged reinforced concrete buildings
• Adding three buildings damaged in Mexico City in 2017
• Leveraging NIST funding by collaborating with U of Auckland team

funded by NZ government

• Seismic Analysis and Design of Nonstructural Components and

Systems (Task Order) – completed

• Developing Cost-Estimating Relationships

Between Federal Building Profiles and Seismic Retrofit Costs – AEO and EEG Joint Project; continuing

national earthquake hazards reduction program

Thrust 4: Support for NEHRP

national earthquake hazards reduction program

Accomplishments in FY2018

• Main deliverables/milestones in FY18:
• IO workshop and report
• FRP workshop
• Six papers and presentations at the 11NCEE
• One presentation at the AISC Steel Conference,

and two presentations at ASCE Structures Congress

• Blind prediction contest on steel beam columns at

AISC

• Complete collapse assessment of 6 special

moment frames

• Completed the element-level uncertainty studies
• Completed the beam-column testing

national earthquake hazards reduction program

FY2018 2EG – Outreach Activities

• Ongoing outreach to the EQ Community
• NIST Exhibited at SEAOC convention in September 2017
• NIST Exhibited at ASCE Structures Congress
• NIST Exhibited at EERI 11NCEE in June
• NIST Sponsored Blind Prediction Contest for Analysis Accuracy

– results at AISC North American Steel Conference

• Organized a Session for National Hazards Workshop in July

regarding IO

• Organized and held a Research Symposium at NIST

Concerning FFO Research

• Organized a Workshop at NIST Concerning FRP systems

national earthquake hazards reduction program

Accomplishments in FY2018

• Collaborations ongoing or established
• CoE, Resilience Group, and NCST investigation
• Applied Economics on seismic strengthening costs
• Worked with Structures Group on new lab equipment; COR

services for purchases for MTS, ASR, and Polymer Group lab equipment

• Projects with University of Utah, Texas San Antonio, University of

California Los Angeles, University of Colorado, and Oregon State University

• Department of Veterans Affairs
• PREP project with Johns Hopkins

national earthquake hazards reduction program

Planned Deliverables/Milestones for FY 2019

• Design archetype coupled shear walls for the HSRB project
• Design test specimens for walls and coupling beams
• Conduct collapse assessment of a set of buckling-restrained

braced frames.

• Acquire/fabricate experimental setup for EBF link tests
• Develop a research plan concerning the FRP research
• Design of archetype CEUS buildings (in progress)
• Write journal papers on IO (in progress)
• Publish papers on the uncertainty quantification project
• Department of Veterans Affairs project peer review

national earthquake hazards reduction program

ACEHR Recommendations for NIST Research

• NIST Recommendation 1
• ACEHR recommends that NIST initiate development of nationally-

applicable seismic performance objectives, assessment procedures, and design criteria for lifeline systems.

• NIST response:
• NIST agrees that lifelines are a critical element in modern communities

and need comprehensive attention to develop next generation performance objectives, assessment tools and overarching design and performance criteria. Planning to address this issue will require the input of stakeholders including communities, lifeline system operators, codes and standards developers and engineering professionals. The lifeline program requested by ACEHR would require a significant investment of Program funding as well as time to bring this recommendation to realization.

national earthquake hazards reduction program

ACEHR Recommendations for NIST Research

• NIST Recommendation 1, continued
• NIST response, continued:
• The reallocation of resources to meet the goals of this work, while

important and worthwhile, must be carefully considered, planned and weighed against other activities to make a large effort of this kind

• succeed. In the current budget realities, reallocation of resources to

address lifelines will likely require some planned research topics to be delayed or abandoned. Input regarding lifeline systems and the ACEHR perspective on specific aspects of this problem that should be prioritized is requested.

national earthquake hazards reduction program

ACEHR Recommendations for NIST Research

• NIST Recommendation 2
• ACEHR recommends that NIST assess the seismic

performance of buildings in the eastern and central United States that have been designed primarily for code-compliant wind loads.

• NIST response:
• The performance of Central and Eastern US buildings in a mixed

environment of high design wind and moderate to significant seismic risk is of great interest to NIST. A current project is underway to develop the first set of study buildings to address this topic. Work is being conducted by the NIST Earthquake Engineering Group in conjunction with the NIST Community Resilience Center of Excellence. Design is being done by an outside contractor. Evaluation of the performance of these buildings will commence once the initial set of buildings is received from the design team in FY2020.

national earthquake hazards reduction program

ACEHR Recommendations for NIST Research

• NIST Recommendation 3
• ACEHR recommends that NIST develop a proof-of-concept

initiative to use a building seismic rating system to evaluate the expected performance of a portfolio of building types.

• NIST response:
• This recommendation will be reevaluated if and when a

workshop on the current state of building rating systems is

• completed. Further, this topic is dependent on potential strategic

plan changes and we look forward to articulation of priorities from ACEHR as input into the decision process.

national earthquake hazards reduction program

Questions?

national earthquake hazards reduction program