Subcommittee on Research
Committee on Science
As a representative of one of the four primary federal agencies that comprise the National Earthquake Hazards Reduction Program (NEHRP), I congratulate the earthquake community and our three partners – the Federal Emergency Management Agency as lead, the United States Geological Survey, and the National Science Foundation – as we celebrate the 25th anniversary of the founding of NEHRP.
NEHRP has been an extraordinary, and often exemplary, collaboration between federal agencies, state and local governments, and the private sector.
During its first 25 years, NEHRP has contributed in very significant ways to reduce our nation’s vulnerability to earthquakes and NIST is proud to have been a part of that record of accomplishment.
While it is difficult to quantify loss prevention through
the adoption of improved mitigation practices, and such measures are very much needed,
there is no doubt that NEHRP products and results have contributed in
significant ways to reduce the loss of life and economic losses from earthquakes. In addition, the loss of life from
earthquakes in the
My testimony traces how NIST has contributed to the success of NEHRP. It also reflects upon the broader public safety challenges the nation now faces and how NEHRP can contribute to meeting those challenges.
Earthquakes and
Creation of NEHRP
Earthquakes are among the most frightening and devastating natural disasters. They strike virtually without warning, last only seconds, but can leave death and destruction in their wake.
Seventy-five million
Americans in 39 states face significant risk from earthquakes. On an annualized basis, earthquake losses
amount to about $4 billion a year, while a single earthquake has a loss
potential of $100 billion or more.
For example, the 1971
The
Pre-NEHRP Efforts
Prior to
the creation of NEHRP, NIST and many other government, private-sector
organizations and universities were conducting research on ways to improve the
seismic design of constructed facilities.
NIST began work in
earthquake hazards reduction with its organization in 1969 of the U.S.-Japan
Panel on Wind and Seismic Effects under the U.S.-Japan Program in Natural
Resources. This successful bi-lateral
program continues to this day, with the 35th annual meeting slated
to be held next May.
NIST work also included
its significant investigation of the performance of structures in the 1971
Also, in
1972, the Applied Technology Council, an organization created by the Structural
Engineers Association of California, called for a cooperative effort of
practice, research, and government to produce up-to-date seismic design and
construction provisions. A subsequent
ATC study completed in 1978 produced design provisions that were a significant
advance on existing provisions.
Role Assigned for NIST in NEHRP
NIST was a natural part
of NEHRP because of its long-time role in providing measurements, standards,
and technology to help federal, state, and local government agencies and the
private sector protect the nation and its citizens from natural as well as
manmade threats.
As part of NEHRP, NIST
took on three assignments:
·
First, to develop
seismic design and construction standards for consideration and subsequent
adoption in federal construction, and encourage the adoption of improved
seismic provisions in state and local building codes;
·
Second, to assist
and cooperate with federal, state, and local agencies, research and professional
organizations, model code groups and others that are involved in developing, testing,
and improving seismic design and construction provisions to be incorporated into
local codes, standards, and practices; and
·
Third, to conduct
research on performance criteria and supporting measurement technology for
earthquake resistant construction.
In addition, as part of
the USGS-led Post-Earthquake Investigation Program established by the NEHRP
Reauthorization Act of 1990, NIST took on another assignment:
·
Fourth, to participate
in NEHRP post-earthquake investigations and analyze the behavior of structures
and lifelines, both those that were damaged and those that were undamaged, and
to analyze the effectiveness of the earthquake hazards mitigation programs and
actions and how those programs and actions could be strengthened.
Products and Results from NIST’s Problem-Focused R&D
Through laboratory based
problem-focused R&D NIST has made important contributions to earthquake
safety over the years. Examples include
our products and results related to:
·
bridge column
reinforcing requirements,
·
rehabilitation of
welded steel moment frame connections,
·
test methods for
passive and active seismic energy absorption systems, and
·
precast concrete
frames.
One example is our work with industry and others on precast concrete
frames (Attachment A provides summaries of the other examples).
While construction with this
type of frame has not been extensive in high seismic regions of the
In 1987, NIST initiated a
project to develop a precast beam-to-column connection that was economical,
easy to construct, and capable of resisting earthquake loads. A few years later, Pankow Builders, a
Tests at NIST and on a
five-story precast building at the
Recently, Pankow Builders
used the hybrid connection to build a $128-million, 39-story building in
Several other structures
using the hybrid connection have been built, are underway, or on the drawing
board.
We are very proud of our
collaboration with Pankow Builders, the
Lessons Learned from NIST’s Post-Earthquake
Investigations
Throughout
its history, NIST scientists and engineers have been called in to investigate
building failures following fires, earthquakes, high winds, terrorist attacks,
construction accidents, and other events.
Tragically, we learn many
lessons following an earthquake about what type of design and construction
works and what does not. Our goal is to
investigate and document building performance and the adequacy of current codes
and practices, as well as to identify research needed to mitigate the impact of
future earthquakes.
Our investigators have traveled not only to earthquake sites
in the
Since NIST is not a regulatory agency and does not issue
building standards or codes, the institute is viewed as a neutral,
“third-party” investigator. Our
investigations are fact-finding, not fault finding. The focus is on improving public safety and
on deriving lessons for the future. And,
by law, the data, analysis, and reports resulting from NIST investigations may
not be used in litigation.
Formation of ICSSC and Federal
Construction
One of the early accomplishments of NEHRP was to involve
federal agencies with construction responsibilities. Federally-constructed facilities comprise one
of our nation’s largest building sectors.
It was realized early in the NEHRP that it was vital to assist the more
than 30 federal agencies that are involved in one way or another in
construction to implement earthquake hazards reduction elements into their
ongoing programs.
In 1978, the White House directed the Federal Emergency
Management Agency to form an Interagency Committee on Seismic Safety in
Construction (ICSSC). ICSSC was assigned
to develop and implement seismic deign standards for federal construction. NIST, with funding from FEMA, has provided
the secretariat for ICSSC since its inception, and the Director of NIST (or the
Director’s designee) has chaired the ICSSC since 1982.
Not only did the ICSSC provide up-to-date seismic design and
construction standards and practices that federal agencies used for their own new buildings, but it had a broader
effect as well. An executive order issued
by the President in 1990 required both federal and federally-assisted homes,
such as new homes with FHA or VA mortgages, be designed and constructed using
these standards.
This federal mandate was
welcomed by the national standards and model building code organizations since
it provided incentive for state and local governments to adopt and enforce
up-to-date standards and codes to be eligible for federally-assisted
construction.
The bottom line result
was that NEHRP’s broad goal of making adequate seismic resistance available for
all new
ICSSC was much involved
in support to federal agencies in implementation of the executive order for new buildings. It continues today to provide support for the
assessment of the equivalency of model building codes to the NEHRP recommended provisions
– the most recent assessment was issued in late 2001 – and the development of proposed changes to
model codes.
The ICSSC turned next to
the challenge of evaluating and strengthening existing buildings by developing seismic safety standards and
assisting federal agencies in implementing a second executive order. That executive order called for agencies to
inventory buildings they own or lease and estimate the costs of mitigating
unacceptable seismic risks.
The ICSSC developed
policies and practices for evaluation and strengthening of existing federal
buildings. This included seismic safety
standards for existing buildings, which were updated recently; guidance to the
federal agencies on implementation of the executive order; assistance with estimating
the costs of mitigating unacceptable seismic risks; and extensive review and
comment in drafting the resulting report.
Currently, ICSSC is developing a handbook for the seismic
rehabilitation of existing buildings.
This handbook will facilitate implementation of the seismic
rehabilitation plan for federal buildings when a policy decision is made to
proceed.
Major Challenges for the
Future
NEHRP has come a long way.
But, it faces many challenges in meeting its legislative mandate to
“reduce the risks of life and property from future earthquakes in the
Four of the key challenges faced by NEHRP are to:
·
fill
the technology transfer gap between basic research and practice,
·
develop
and implement seismic safety standards for lifelines,
·
develop
and implement a multi-hazard approach to risk mitigation, and
·
better
coordinate post-earthquake investigations.
Challenge #1: Filling
the Basic Research to Practice Gap in Earthquake Engineering
Just as NEHRP strives for
better ways to improve the performance of construction during an earthquake,
NIST and its three NEHRP partners are continually looking for better ways to
carry out our mission.
Early in 2001, a NEHRP
Strategic Plan was approved by each of the four participating agencies. This plan, developed in partnership with
stakeholders, has identified the emergence of a technology transfer gap that limits
the adaptation of basic research knowledge into practice. The plan recommends a much-expanded
problem-focused research and guidelines development effort:
·
to develop future
design, construction, evaluation, and upgrade guidelines and standards of
practice, and
·
to facilitate the
development of new mitigation technologies.
It further recommends
that NIST, in partnership with FEMA and other NEHRP agencies, should develop a
coordinated plan to support this effort.
NIST looks forward to
working with its NEHRP agency partners and with industry, academia, and the
broader stakeholder community to address this gap.
As a first step, NIST
requested the Applied Technology Council, a non-profit corporation to advance
engineering applications for natural hazard mitigation, to convene a workshop of
national leaders in earthquake design, practice, regulation, and construction in
July of 2002.
The purpose of the
meeting was to assess the state of knowledge and practice and to suggest an
action plan to address the gap between basic research and practice.
Recently completed, the
action plan identifies industry priorities in two areas:
·
support for the seismic code development process through
technical assistance and development of the technical basis for performance
standards; and
·
improved seismic design productivity through the
development of tools and guidance and evaluation of advanced technologies and
practices.
This action plan fits
within the broader research and outreach plan developed by the Earthquake
Engineering Research Institute titled “Securing Society Against Catastrophic Earthquake
Losses.” It also incorporates issues
raised under Challenge #2 below.
NIST now looks forward to
working with the stakeholder community to explore ways to best meet those needs
via a public-private partnership. We
expect this effort will build on NSF-funded basic academic research, including
that conducted as part of the George E. Brown, Jr. Network for Earthquake
Engineering Simulation (NEES) Consortium.
Challenge #2: Developing
and Implementing Seismic Safety Standards for Lifelines
While up- to-date seismic
provisions for building codes are available today, there are no nationally
accepted standards or guidelines for lifelines, except for highway structures
and nuclear facilities.
Lifelines include all types of transportation (highways,
airports, railways, waterways, ports and harbors), communication, and utility
(electric power, gas and liquid fuels, water and wastewater) systems. They provide the physical infrastructure that
support most human activities.
The American Lifelines
Alliance, with support from FEMA, is working on the development of guidelines
and standards for lifelines. Concurrently,
the ICSSC has completed an initial survey of lifelines that are the
responsibility of federal agencies. It
has begun a major effort to identify the needs for standards and guidance for
these lifelines, with an initial focus on electric power generation,
transmission, and distribution facilities. It is anticipated that implementation of the
lifelines plan would be primarily through the existing voluntary standards
system with a possible executive order requiring agencies to adopt and use the
standards for federal lifelines.
While these initial public and private sector efforts are
laudable, I believe NEHRP has much work to do before the nation will have
seismic standards and guidelines for lifelines similar to those we already have
for new and existing buildings.
Challenge #3: Developing and Implementing a Multi-Hazard
Approach to Risk Mitigation
Seismic hazards are one
of many significant hazards that must be considered in design and
construction. From the viewpoint of an
owner or end-user, a multi-hazard approach to risk mitigation is desirable
since it likely will yield more cost-effective solutions. This is especially true for existing
construction, where seismic retrofit investments may be better justified when
made in conjunction with needed functional and security upgrades.
A careful consideration of regional hazards such as
earthquakes and high winds shows that these hazards pose a major risk since
they coincide with geographical areas that have seen significant population
growth and development in recent years.
The risks from fire hazards are spread across the nation, while the
risks from terrorist or technological threats are limited to certain critical
facilities or locations.
In comparison with the $4
billion annualized loss estimate for earthquakes, the annualized loss estimate
for extreme winds is about $8 B/year and for fire hazards is about $12 billion
a year. Similarly, in comparison with
the $100 billion loss potential for a major earthquake, a single hurricane
event has a loss potential of as much as $50 billion. Major earthquakes, high winds, and other
extreme hazards have one thing in common – they are all low probability, high
consequence events.
There is significant merit to multi-hazard risk mitigation
if practicable tools, practices, and guidance can be developed. Examples include:
·
improving
overall structural integrity by mitigating progressive collapse, where NIST is
already working with the private sector to develop needed tools and guidance;
·
conducting
multi-hazard vulnerability assessments using an integrated framework based on
standard information representation models and interoperable software tools;
and
·
evaluating
the cost-effectiveness of alternate risk reduction technologies and strategies
using integrated software tools for making cost-risk trade-offs.
I believe NEHRP has a unique opportunity to provide national
leadership in charting the course for a multi-hazard approach to risk
mitigation, while continuing with its important risk reduction mission for
earthquakes. The development of the
HAZUS regional loss estimation model – that now covers earthquakes, wind, and
floods – is an excellent example of how NEHRP has already demonstrated this
kind of leadership.
Challenge #4: Coordinating Post-Earthquake Investigations
NEHRP has long supported post-earthquake investigations, and
in 1990 Congress specifically authorized the establishment of a coordinated
program to conduct such investigations with leadership to be provided by the
United States Geological Survey.
Consistent with this legislation and the recent NEHRP Strategic Plan, an
implementation plan has been completed to coordinate future post-earthquake investigations.
In the aftermath of the
That law, Public Law
107-231, established NIST as the lead agency to investigate building
performance, emergency response, and evacuation procedures in the wake of
building failures that result in substantial loss of life or that posed
significant potential of substantial loss of life. Currently, NIST is conducting two major
investigations: a building and fire safety investigation of the
NIST is developing agreements
for future investigations with other federal agencies, and with the private
sector so that we can quickly and effectively deploy investigation teams and so
that we can share the results of those investigations and related research.
The National Construction Safety Team Act gives NIST the
authority to dispatch teams of experts within 48 hours when practicable. The law gives the teams a clear authority to:
·
Establish
the likely technical cause of building failures;
·
Evaluate
the technical aspects of procedures used for evacuation and emergency response;
·
Recommend
specific changes to building codes, standards and practices;
·
Recommend
any research or other appropriate actions needed to improve the structural
safety of buildings, and/or changes in emergency response and evacuation
procedures; and
·
Make
final recommendations within 90 days of completing an investigation.
The act gives NIST and its investigation teams comprehensive
authorities to:
·
Access
the site of a building disaster;
·
Subpoena
evidence;
·
Access
key pieces of evidence such as records and documents, and
·
Move
and preserve evidence.
Congress anticipated the NCST Act to be applicable to
building failures caused by earthquakes.
The Act specifies that the NIST Director develop implementing procedures
that “provide for coordination with Federal, State, and local entities that may
sponsor research on investigations of building failures, including research
conducted under the Earthquake Hazards Reduction Act of 1977.” In addition, the Committee Report 107-530
published by the House Science Committee on
NIST’s responsibilities under the NSCT Act have been
incorporated in the recently completed plan to coordinate post-earthquake
investigations issued by the four agencies comprising the National Earthquake
Hazards Reduction Program. The plan
(USGS circular #1242) states that, within 48 hours, NIST will examine the
relevant factors associated with building failures that occur as a result of
the earthquake and will make reasonable efforts to consult with the other NEHRP
agencies prior to determining whether to conduct an investigation under the
Act. Any NIST investigation conducted
under the authority of the Act will be limited to building failures on one or
more buildings or on one or more class or type of buildings selected by NIST.
Conclusion
As
we look to the future, I believe NEHRP will continue to play a vital leadership
role in making the performance of our buildings and lifelines highly measurable
and predictable. This measurement and
prediction ability will provide the critical underpinning upon which to achieve
specified levels of performance and seismic risk reduction via workable and
practicable solutions. Our nation will
be safer and more secure for it.
We at NIST look forward
to contributing our part to address the challenges that lie ahead.
Attachment A
Products and Results of NIST Problem-Focused R&D
Bridge Column
Reinforcing Requirements
Immediately following the 1971
NIST initiated a project
in the 1980s to provide the necessary verification, consisting of two
full-scale bridge column tests. The
challenges arose from the size of the test specimens and the need to apply
horizontal seismic loads in addition to vertical gravity loads. The series of column tests was the first of
its kind and as such, provided important benchmark data. The tests also verified the adequacy of the
revised design specifications.
In addition, NIST tested
companion 1/6-scale bridge columns and the results indicated that the behavior
of full-scale bridge columns could be extrapolated from small-scale bridge
column tests. This finding suggests that
high costs associated with full-scale tests are not always necessary and less
expensive small-scale tests may be sufficient.
Welded Steel Moment Frame Connections
Steel framed buildings
traditionally have been considered to be among the most seismic resistant
structural systems. The January 17,
1994, Northridge Earthquake, however, caused unexpected damage to many welded
steel moment frame buildings. In
general, the damage was confined to beam-to-column connections that suffered
brittle fracture in the flange welds.
In response to these
failures, NIST initiated a project to study methods to modify existing
buildings to improve their seismic performance, in collaboration with the
American Institute of Steel Construction, the
The result of this
multi-year effort was the publication of comprehensive guidelines for seismic
rehabilitation of existing welded steel frame buildings as an AISC Design
Guide. The guidelines provided experimentally-validated response prediction
models and design equations for the three connection modification concepts that
shift loading from the welded joints into the beams, thus enabling the
structure to absorb the earthquake’s energy in a non-brittle manner.
Test Methods for Structural Control Devices
Structural control
devices, such as seismic isolation and passive energy dissipators, have been
installed in numerous structures throughout the world and have proven to be
effective in reducing both motions and forces during earthquakes and strong
winds. Still these devices are generally
produced in small quantities, specifically for each application.
To guarantee that the
devices will perform as the designer expected, many building codes and
guidelines recommend that the devices be tested before installation. While some of these standards describe a
limited number of specific tests, widely accepted test standards do not yet
exist. Such standards are useful to
designers, manufacturers, and contractors, since they will make the process of
validating these devices consistent.
To address the issue NIST
has developed two sets of testing guidelines.
The Guidelines for
Pre-Qualification, Prototype, and Quality Control Testing of Seismic Isolation
Systems was issued in 1996. ASCE has
developed and is currently balloting a national consensus standard based on the
NIST-developed isolation device testing guidelines.
While seismic isolation
is generally accepted in earthquake engineering practice and recognized in the
building codes in high-seismic areas, passive structural dampers are still
gaining acceptance and semi-active devices are still in the development
phase. NIST has just issued Guidelines for Testing Passive Energy
Dissipation Devices.