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Determining the Reliability of A Seismically Assessed Building Conclusion Using A Modified FEMA P-154 Procedure
Charles C Thiel1* and Theodore C Zsutty2
11Department of Telesis Engineers, USA
2Department of Consulting Engineer, California, USA
Submission: August 24, 2022; Published: September 09, 2022
*Corresponding Author: Charles C. Thiel, Department of Telesis Engineers, Inc, 634 Las Barrancas Drive, Danville, California 94526, USA
How to cite this article:Charles C T, Theodore C Z. Determining the Reliability of A Seismically Assessed Building Conclusion Using A Modified FEMA P-154 Procedure.Civil Eng Res J. 2022; 13(2): 555858. DOI 10.19080/CERJ.2022.13.555858
Abstract
The quality of seismic risk management decisions depends on professional judgements. Such require an assessment of the reliability of the thought process and information used to give them credibility. The goal is to develop a process that assesses the reliability of a traditional P-154 assessment to determine whether it is sufficiently reliable to warrant action. P-154 is a triage approach meant to determine whether a detailed engineering assessment is required or not. Modifications to the P-154 procedures are proposed to warrant such actions without additional engineering assessment. This involves requiring highly experienced evaluators, specification of building document review, and technically independent supervision. Based on the nature of the conclusions, whether using the modifications or not, the reliability of the assessment can be evaluated, and a decision made whether it warrants action. It was validated by application to 56 likely hazardous buildings on three CSU campuses. The result of application of P-154 was that 52 of the 54 buildings need further engineering evaluation to reach a decision: two needed immediate attention, 12 requiring work overtime, where the reliability of all the evaluations indicated a good reliability for the conclusions, when the companion paper’s procedures for portfolio management were implemented. The application of the recommended approach was about $2,500 per building, including assessor time, travel, and expenses, more than the conventional P-154 cost but far less than the engineering P-154 assessment. A companion paper, Setting the Priority for Seismic Retrofit of Buildings Using a Modified FEMA P-154 [1] Procedure develops the seismic management program using this reliability determination as a key ingredient. The principal impact of the Modified P-154 process is that the retrofit decisions it recommended had acceptable reliability to CSU management and their advisors.
Keywords: Retrofit; Earthquake; Damageability; Structural evaluation; Safety; Financial risk; Seismic evaluation
Introduction
Seismic risk management decisions depend on risk assessments based upon professional judgements. Some judgements are predictive and can be verified when the outcome becomes known in a short to medium time period. However, many judgements are unverifiable in part because of the time period over which they apply. Determining acceptable seismic performance of a building falls in this latter category. The quality of such judgments can be assessed only by the quality of the thought process and information that produced them. The seismic risk management program for the California State University’s building stock has been underway since 1993. For a given potentially hazardous building, this document presents how the current seismic risk evaluation is performed for the purpose of setting a priority for retrofit. For the objective of providing prudent, legally defensible decisions, the risk evaluation and retrofit priority assignment will be by a continuing, consistent, transparent, and documented assessment process. Procedures developed for FEMA will be employed. The authors have participated in this process for CSU since 1993. While the following procedures were initially intended for application to CSU buildings, they can be used by any individual or public or private organization desiring to evaluate the reliability of a seismic safety assessment of a building or group of buildings and their need for seismic retrofit. This is part of a two-paper set. The objective of this paper is to develop a modified P-154 assessment procedure, and then provide a means of assessing the reliability of its conclusions for a given building. The companion paper, Setting the Priority for Seismic Retrofit of Buildings Using a Modified FEMA P-154 [1] Procedure, proposes how to aggregate the P-154 conclusions on a series of buildings to set priorities for retrofit with an index 
without
adopting a risk adverse priority given in P-154 of immediately
assessing the hazard posed by the building with a 
. As
noted in the end of this paper, such when applied to CSU assessed
buildings would yield needs for Capital Planning to assess all but
four of the 56 buildings assessed, with implications for massive
capital requirements that are not available. Sound seismic risk
management requires a knowledge of both the level of the risk
of a building and the reliability of its assessments. The authors
suggest that the first action of an organization wanting to make
such an assessment(s) is to appoint a Consulting Board (CB)
of seismic experts who do not perform the subject building
evaluation assessment(s), not less than two and ideally four to
seven, depending on the portfolio under consideration and how
many assessments are to be performed per year to technically
supervise this process. Depending on available resources, selected
individual assessors should be assigned to assess a proportion
of the group of potentially hazardous buildings. The authors
have selected to approach these assessments using a modified
FEMA P-154 [1] procedure. The original P-154 Rapid Visual
Screening (RVS) process was intended for a wide-spread regional
seismic risk assessment without the significant cost of detailed
engineering inspections or analyses. Its purpose was to identify
buildings that warrant significant engineering evaluation before
assessing its relative risk. The RVS assessment procedures permit
use by assessors that may have a wide range of qualifications
and help identify buildings that should be assessed in detail. The
purpose herein is to identify the priority for such assessments and
not require further assessment until a time when it is appropriate.
The Assessment Procedure
The goal of this procedure is to distinguish Good buildings from Bad buildings quickly with limited information and great uncertainty and then determine how limited resources should be used to the greatest advantage by distinguishing really Bad buildings from those that are so-so Bad. There have been many studies of the psychology of how such processes operate and what can be done to improve them (Kahneman, 2011). Heuristics and biases perspective, as conceptualized by Kahneman and others, was viewed by the authors as the underlying theoretical foundation for the development of this assessment procedure. Heuristics are mental shortcuts that individuals use when making complex decisions. They are generally helpful but can lead to systematic errors, which are called biases. One heuristic that applies here is Anchoring, the ease with which a recent decision comes to mind and then influences subsequent decisions. For instance, a structural engineer who has just triaged an unreinforced masonry building that has not been retrofitted to adequate standards assigns it to the really Bad status and does not consider it further for occupation because she/he knows that very few URM buildings can meet the stability requirements of the current building code. This is accepted notwithstanding the fact that in the 1933 Long Beach earthquake, 42% of the threestory URM load bearing wall buildings had less than 20% damage, and only 19% had over 50% damage, and so it was concluded that no additional investigation was warranted. Cioff (1998) reported that experienced nurses used more heuristics than inexperienced nurses, and that in conditions of uncertainty both experienced and inexperienced nurses used more probability judgments. The authors have no doubt that the same is true for structural engineers working with the same type of resource and time limitations for evaluations. A second bias is termed Theory-Induced Blindness: Once you have used a theory as a tool in your thinking, it becomes extraordinarily difficult to notice its flaws; your brain wants to do what it knows will ensure its survival. A third is Confirmation Bias: The tendency to notice, accept, and remember information that appears to support an existing belief and to ignore, explain away, or forget information that seems to contradict the existing belief. This is not a conscious act, and thereby much more unlikely to be realized, except where there is external challenge. In the experience of the authors, all of these biases, and many more, can cause real problems in structural engineering, particularly where decisions are not challenged on their bases and conclusions. And doing triage of a building’s performance is a prime candidate for these and other biases to reap havoc. Keeping these biases, and others not discussed, was a goal of the developed procedure. This was approached by:
a. Having highly skilled and experienced structural engineers do the evaluations.
b. Having the ability to change the conclusions from the right formulaic approach where the evidence and so indicate, and the case can be made.
c. Having the individual conclusions discussed in the working group with the goal of finding weakness in the reasoning that led to the conclusion.
d. Having a second level review by the Seismic Review Board to act as a second screen validation of the conclusions.
The P-154 method of seismic assessment has been selected
because it is an accepted FEMA standard, and its resulting 
score allows the evaluation of the relative probability or risk
of collapse due to all possible levels of seismic ground motion
at the building site over a given time period. Knowledge of this
Risk Measure for a particular deficient building allows a rational
basis for decisions concerning prioritization of the related retrofit
work. In contrast, the seismic provisions of ASCE 7 [2] for new
buildings provide only the conditional risk taken as equal to 10%
of a compliant building not meeting the ASCE 7 [2] performance
objectives (collapse avoidance) due to the Maximum Considered
Earthquake (MCER) level of site ground motion. This is a scenario
ground motion-based representation of performance and does not
reflect the probabilities that collapse could and will occur at lower
ground motions than the MCER. The actual risk must include the hazard due to both lower and possibly higher levels of ground
motions, and all the likelihoods of the building’s response to any
ground motions to which it is exposed. For existing buildings,
the ASCE 41 [3] Tiers also depend on scenario ground motions
for evaluation. Similarly, the Californian Existing Buildings Code
(CEBC) provisions for existing state-owned buildings treat building
performance at two scenario ground motion Levels I and II, and
thereby do not provide the total risk for rational decisions. None
of these design standards use the ASTM E2026-16a [4] concept of
Probable Loss that considers all possible ground motions to which
a building could be subjected over a given time period, as well as
the statistics of how the building could respond to a given ground
motion level. For the purpose of retrofit priority assignment, it
is necessary to determine the Probable Loss corresponding to a
fixed time period. Fortunately, the detailed analytical bases for
P-154, given in FEMA P-155 [5], provides the required Probable
Loss measure approach. This is obtained by the evaluation of the
Risk Score SR = SL2 +1, which represents the degree of hazard
per unit time for a specific location. For the specific application
to the CSU Assessment Procedure, it is necessary to correct the
downside aspect of P-154 as originally intended to be a Rapid
Visual Screening (RVS) of buildings that could potentially pose a
collapse risk. Per P-154 Section 1.6, it is intended that RVS results are to be reviewed by an expert structural engineer in order
to provide the need for a more detailed analysis and possible
retrofit. For the 2021 CSU Assessment, the screening process has
the following improvements to the RVS process: the necessity for
review of available construction documents, the use of expert
assessors, the necessity of a building site visit, the assignment
of quality of information, and a required peer review process.
CSU has undertaken to change the terms and conditions of how
the P-154 assessments are done. Its objective is to allow the
determination of the risk category for a building having potential
deficiencies in seismic resistance. The proposed changes in the
RVS process are outlined in Section 3. The P-154 Level 1 and 2
Forms for the High Exposure region, as reproduced in (Figure 1)
[1], provide initial scores for each structural performance-related
item of a building, and as discussed previously, the assessor may
modify the initial score based on the structural characteristics
of the building and corresponding expertise of the assessor. The
forms vary by seismicity region; Very High, High, Moderately
High, Moderate, and Low seismicity forms each have a unique
set of basic scores for the basic building types considered but are
otherwise identical. (Table 1) gives the distinctions among these
zones. See P-154 for these forms.
Proposed Changes to the RVS Process
For setting the priority process for Seismic Risk Assessment,
the authors have elected to use a modified version of the P-154
Rapid Visual Screening (RVS) Method discussed below. The
RVS procedure was developed to identify, inventory, and screen
buildings that are potentially seismically hazardous and intended
for use by a wide range of screeners including: civil engineers,
structural engineers, architects, design professionals, building
officials, construction contractors, firefighters, architectural
or engineering students, or other individuals with general
familiarity or background in building design or construction.
The P-154 requires a supervising structural engineer to review
all scores. This backup requirement for an expert review of the data collection allows the use of a broad range of individual
qualifications for the assessors. Once identified as potentially
hazardous, the subject building should be further evaluated by a
design professional experienced in seismic design to determine if,
in fact, the building is seismically hazardous. The RVS procedure
uses a methodology based on a sidewalk survey of a building and
use of Data Collection Forms. These forms are completed by the
person conducting the survey, and the resulting scores are based
on information obtained from visual observation of the building
from the exterior and, if possible, the interior. It is important to
recognize that the reliability and confidence in the determination
of a building’s attributes would be increased if the type and
condition of the structural system were to be evaluated by a highly
qualified assessor performing the exterior and interior screening,along with a review of available construction documents (as will
be the case for the CSU Assessment). The P-154 Data Collection
Forms 1 and 2 (Figure 1) include limited space for documenting
building identification information, including its use and size, a
photograph of the building, and sketches. Further, Forms 1 and 2
provide a list of critical items and corresponding scores related
to the seismic resistance of the building. The score 
is used
as a measure of the seismic vulnerability of the building. Also,
most importantly, there is a Comments section on Form 2 to
describe and justify specific attributes or conditions that could
alter the reliability of the initial 
score as an indicator of
collapse vulnerability. This allows CB interpretations and score
adjustments to the general structural items as listed on Forms 1
and 2. The original RVS method identifies building attributes that
may contribute to poor seismic performance, and conservative
assumptions concerning the score values for these attributes have
been made to minimize calling a Bad building Good. However,
because RVS is intended to be performed from the sidewalk,
where interior inspection is not always possible, and because
there is no requirement for review of construction documents,
hazardous details will not always be detected, and seismically
hazardous buildings may not be detected as such. Conversely,
buildings initially identified as potentially hazardous by RVS may
prove to be adequate. Therefore, recognition of the reliability of
the P-154 RVS assessment becomes an important issue. Clearly,
there can be a wide range of reliability in the determination of a
P-154 score. The P-154 scores are based on a representative level
of damaging ground shaking levels for the prescribed seismicity
region, and they are intended to reflect the seismic design and
construction practices for this region. Consequently, a building in a
HIGH seismicity region will have generally been constructed with
more seismic resistant systems and details than a similar building
in a LOW seismicity region. Also, seismic design and construction
practices vary and are not necessarily uniform across regions of
the State having similar seismic risk. The appropriately evaluated
P-154 score has the advantage that it is intended to yield consistent
measures of collapse probability across different building systems
and seismic exposures. For the user agency, CSU, it is therefore
important for decisions concerning assignment of resources that
the reliability of the methodology leading to an assessed score be
evaluated. For example, the reliability of a score developed by an
experienced seismic structural engineer should not be the same
as that by an inexperienced architect; or a score developed from
information obtained from complete construction documents
along with a thorough visual inspection of the building should be
superior to that where neither of these actions took place. In the
CSU modified RVS procedure, SUPERIOR quality is assigned when
complete construction documents are available and reviewed and
a thorough site visit has been performed by the expert assessor.
In contrast, with the initial RVS process, FAIR to POOR quality
can result from a building walk-around by a person of limited
capability. CSU needs this extra reliability or quality evaluation
for prudent allocation of funds and use of time for seismically deficient buildings. The recommended screening process is
intended to place each building on lists that reflect its degree of
seismic hazard without further evaluation. In order to achieve this
objective, the CSU has chosen not to implement the initial P-154
RVS procedure as presented. The modified RVS is intended to be
a self-contained process, not a preliminary process, that provides
definite identification of seismically deficient buildings along
their hazard of collapse during a specified time period. As a result,
prudent decisions for retrofit can be implemented as a part of the
ongoing seismic Risk Management program. Therefore, with this
goal in mind, the initial P-154 RVS process has been modified to:
a. Restrict the assessors to be highly skilled and knowledgeable earthquake engineers who are members of the CB.
b. Require a review of all available structural plans, even if these may be partial, for the construction and for any modifications of the building, together with an on-site review by the assessor of the physical condition of the building and its lateral load resisting system. While past assessment reports may be available and shall be reviewed, no additional structural analysis is required.
c. Require both Level 1 and Level II P-154 score sheets
to be completed to provide the more comprehensive initial 
score. When the assessor finds that the P-154 Form item subscore
does not represent the actual conditions described by the
listed items on the Level 1 or 2 Forms, then scoring adjustments
are to be noted and entered as Comments with an explanation
of the basis for observations. In addition, the assessor must use
the Component Matrices of (Table 2) to assign the Quality of the
available information and the Quality of implementation used by
the assessor for each component in the evaluation process for
review by the CB.
d. The results of an individual assessment will be reviewed
first by the other assigned assessors for consistency, and then by
the CB. The CB review will approve or change the initial 
score
based on their review and augmentation of the Comments sheet.
The CB will review the assessor’s Quality assignments in (Table
2) and finalize it in order to evaluate the reliability of the final
score assignments (the root mean square (RMS) procedure will
be used). Quality represents the reliability of how the P-154 score
represents the seismic risk (collapse potential) of the building. A
specific Quality level is required for assignment of a building to
one of the priority lists for seismic retrofit. For the case where the
Quality level is not sufficient, the building is assigned to a list for
further study.
e. The initial 
score may be adjusted by the CB where
the expert assessor and Board conclude that issues covered and
related score contributions in the P-154 Level 1 and 2 Forms do not
adequately consider related positive or negative characteristics
that are important to the representation of the expected seismic
performance of the building. The assessor’s reasons for these
adjustments are to be documented on the Comments form, and they shall be considered for an appropriate adjustment of the
score at the discretion of the CB after their peer review and
documented acceptance.
f. For a given building, the CB will employ the approved
Risk Score, SR = SL2 +1, as a consideration for the assignment
of the building to the appropriate Priority List. The Risk Score 
has a direct relation to the collapse hazard of the building over
a given time period (see Section 5). Based on the Risk Score, the
Risk category of the building, along with acceptable QUALITY of
the assessment, the CB is to make an appropriate assignment to
one of the Priority Lists.
While the above listed modifications may require more effort than the original P-154 RVS process, they will result in a documented method of determining, with acceptable reliability, which buildings are at highest risk for purposes of List assignment. The extra effort is feasible and does not require a very costly ASCE 41 [3] Tier 3 assessment for its application, which can easily reach multiples of $10,000 in effort to complete. It also allows the successful CSU seismic risk management program to continue on the same basis, with a more consistent, justifiable, transparent, and documented priority setting process.
P-154 SL2 Score Modification
A building seismic assessment 
score can lead to one of at
least four dispositions discussed below:
A. There is inconclusive and/or insufficient information concerning the building such that no conclusion of collapse susceptibility can be made. For example, there may not be any existing drawings to review, and physical observation does not indicate a definitive lateral force resisting system. The required information may be obtained in the next assessment of the campus building or in the next annual seismic assessment review as a special purpose review. It is expected that very few buildings will be assigned this classification.
B. The building is assigned to List 1 as a building posing significant hazard and warranting detailed seismic assessment and retrofit as required under the Organization’s policy triggers. This detailed assessment and retrofit should be implemented as soon as practical.
C. The building is assigned to List 2 as a building posing sufficient hazard to warrant detailed seismic assessment and potential retrofit when any work is proposed that requires a permit. The assessment and retrofit are not subject to any of the triggers of the CEBC that could allow delay in the full assessment.
D. The building has a seismic vulnerability that does not warrant assignment to Lists 1 or 2; that is, it will be assessed and retrofitted if the triggers of the applicable Building Code regulations so require for the issuance of a permit for proposed work.
The latest CSU Seismic Review Board (SRB) and Assessment Group discussions have yielded the following proposed processes for Assessment Submittals and their review and recommendations:
a. The assessor will prepare a P-154 Forms 1 and 2
report, as well as a supplementary discussion of the factors
that were important to the assessment of the 
score. The
supplementary discussion concerns items and conditions that the
assessor considers as important in understanding the hazard of
the building but where these are not adequately reflected in the
items and scoring procedure of P-154. The report may include
additional materials germane to the evaluation. These materials
may include available backup text or previous reports describing
conditions that would justify changes of altering the interpretation
of the assigned 
score and corresponding reliability.
b. The CB shall receive all individual building assessments and review the recommended determination of the disposition of each building.
c. Each assessment report will be reviewed by each CB member who shall consider whether there is cause for review by the full CB. If there is cause, the CB member shall provide a basis for why this was concluded in order to guide the full CB discussion.
d. The CB shall consider any building that is either: recommended by the Assessment Group to be reviewed by the CB, or for which any CB member has recommended a full CB review. The discussion will proceed to consider the basis of the recommendation of the Assessment Group and, if applicable, the cause for additional review as recommended by the individual CB member.
e. The CB will reach a conclusion concerning the disposition of the subject building by recommending an assignment to the appropriate priority list, along with the Quality of the related information
f. The CB shall forward its recommended assignments for each assessed building to the Client.
The procedures of Section 5 are proposed to determine
the modified 
score for the case where there is specific
information concerning building performance that is either
not included or not adequately represented in the P-154 Form
Levels 1 and 2 item descriptions and related scores. This added
information can occur because the assessor judges that the value
for the specific Form item sub-score is either over or under the
appropriate contribution that the added information has on the
collapse hazard of the building. A modification of the initial Risk
Score 
is required to evaluate the appropriate
hazard. The modification is based on the assessor’s evaluation
and experience, and justification as given in the Comments section
of P-154 Form 2. Any change in initial Risk Score must have the
approval of the CB during the peer review process. In any case of
an adjusted score, it is necessary to consider the corresponding
effect on the Probability of Collapse of the structure (see discussion
in Section 5) and whether the corresponding hazard level is
consistent with judgement of the CB. The initial P-154 Rapid
Visual Screening Process is predicated on the assessor having
limited information on the building being evaluated and limited
expertise in evaluation. Therefore, a review by a knowledgeable
professional is required for the building’s disposition. In contrast,
the revised CSU application of P-154 requires that the assessor is
highly qualified, has access to the design drawings, has completed
an interior and exterior visual assessment, and the evaluator’s
recommendation is subject to vigorous technical peer review, first
by the assessment team, and then by the CB. The assessor may
find that an elemental score either over- or underestimates the
contribution to the collapse potential and, therefore, may choose
to modify that score. Section 5 presents examples of ways that can
be used for this purpose, subject to peer review acceptance of the
basis for the modification. When a modification is proposed to
the 
score elements or total, the CB shall consider its basis.
After discussion, each member will be asked to provide the best
assessment of the score modification, and the average of these
shall be considered as the value. P-154 and P-155 discuss the
items or characteristics that affect collapse hazard and how it was
decided on the corresponding score deductions or additions. It is
useful to study these discussions in order to understand their basis
and assumptions, so that their limitations can be understood and
how appropriate changes can be made for given circumstances or
conditions.
Procedures for Modification of Itemized Scores
In some cases, the P-154 element scores may be deemed to
not adequately represent the expert assessor’s evaluation of
the condition’s impact on damageability and ultimate collapse
likelihood. Each modification must be justified by documented
comments on why it was warranted. It is useful to consider the
following examples of how the modifications to the initial 
score may be made in practice.
Example 1: A wood-framed building at a High Seismicity, Soil
Class D Site, with a tuck-under configuration, is initially rated by
P-154 Form 2 as having a Weak or Soft Story, from item 3 (W1A
open front). By observation, the opening is over 50% of the
building length. By P-154 this requires an addition of -1.2 to the
score.
a) This scoring would be appropriate if there were no structural elements that mitigated this condition, and alternatively, that there are no other contributing factors that would cause worse than typical expected performance.
b) If the structure is observed to have wood rot or otherwise
damaged structural elements that could impact the gravitational
stability of the first-story structural system, then it would be
rational to consider that the threshold at which extreme behavior
would initiate is at substantially lower ground motions, and that
it is more hazardous than the 
assigned value of -1.2 would
imply, justifying an additional subtraction of Δ = −0.6 or more.
c) If there were transverse wood end walls over the full width of the building and the supported diaphragm sections have aspect ratios less than 3:1 when the interior transverse shear walls are considered, then it could be argued, using professional judgement, that the penalty is too great, and the positive increment should be of the order of ½ credit of the deduction if they were plywood shear walls, Δ = +0.6 , or Δ = +0.3 if they were straight board sheathing.
d) If the building has full longitudinal plywood shear walls supporting the upper occupied residential story(s) on each side of the center of mass of the building, then a credit of the order of 1/3 might be professionally justified depending on the characteristics of the supported diaphragm, for a credit of Δ = +0.40 .
e) If the building has both transverse and longitudinal shear walls at the first story, as discussed in the prior two bullets, then the open front may be of no consequence to the collapse potential of the building, and Δ = +1.2 is appropriate. If there were one or more frames or wall sections along the open side, then the adjustment might be more than 1.2, based on the decrease of the torsional response.
Example 2: A three-story reinforced concrete (r/c)
rectangular classroom building at a High Seismic Soil Class E
Site constructed about 1962 with no isolated columns, and r/c
diaphragm without ductile detailing of the walls. It has transverse
r/c walls between every pair of classrooms, r/c corridor walls
on each side, and r/c with strip windows on the exterior lateral
walls with short columns/piers between windows. The walls
have detailing typical of the era of construction. For Form 1, the
pre-code C2 value score modifier is -0.70 (note that the closely
spaced shear wall allowance for P2 and RM1 do not apply to a C2 building), and the Form 2 Short Column modifier is -0.4, for a
Δ = +1.2 total score of 
.
a) A simple calculation indicates that for each foot of shear wall at grade, there are 20 sf of floor area. This suggests that the shear walls are likely to crack in the Maximum capable earthquake but not lead to a likelihood of collapse, and that the deduction for the short columns is unwarranted. Also, the penalty for precode detailing is not warranted because Science Buildings with similar construction had limited damage in the 1994 Northridge earthquake at California State University at Northridge (CSUN).
Example 3: A long span roof truss in a pre-code C2(SW)
auditorium has non-conventional connections to a reinforced
concrete wall pilaster. By simple calculation, can this connection,
in this stiff structure, support lateral load without tear-out? If
a review of the connection detail on the plans shows that the
bearing plate anchor bolts have, by current standards, sufficient
embedment with transverse tie reinforcement and concrete cover
to support the estimated load, then the Pre-Code modifier of
(-0.8) is not warranted. Cases such as good detailing, while not
called for in the initial code requirements, were employed by
some California design offices specializing in earthquake resistant
structures-by reputation. If this non-conventional connection
item were to be the only potential deficiency, then the final 
score should be adjusted to be equal or greater than SMIN.
Example 4: Total Score Adjustments based on Assessed
Damage or Base Shear Capacities: If the assessor evaluates the
resulting 
score with or without adjustments to the subscores
as above, then the assessor may also consider making
an adjustment of the 
based upon an aggregate estimate
of the likely performance of the total building based on all its
characteristics, including elements not considered as a part of the
lateral load resisting system, e.g. floor to floor wood framed walls in
residential buildings. A first approach could be to consider the ratio
of the damage values for the P-154 
score and its associated
equivalent damage ratio value of 
to the modified value 
that
reflects the reassessed damageability, including considerations
in addition to those that lead to the P-154 assignment. Since the
value is a measure of the damageability of the building used
by the P-154 process to determine acceptability of the resulting
vulnerability estimate, then the authors can consider the inverse
ratio of the P-154 determined score 
to the modified score
, which considers additional information not included in the
base scoring, as:
Where Δ is the proportional increase (+) or decrease (-) in
the 
value based on the information that was not adequately
represented in the P-154 assessment form. Obviously, a positive
value for Δ indicates lesser damageability, while a negative value indicates greater damageability than the base P-154 score
suggests. Note that the score modification is expressed as the
estimated increase or decrease in the ratio of damageability value,
not absolute values. The authors assume that most experienced
structural engineers think in terms of impact percentage, not
calculated values, to make judgements on seismic performance
as expressed in terms of damage. A second approach would be to
assess the modified value changes if the engineer has an opinion
on how the alternative information may impact the base shear
capacity of the building, V ; then, by use of the TZR model results,
the damageability ratio can be estimated by use of ([6], Part 2,
Equation 2):
where V is the base shear capacity of the design, the right side
of the equation is for where conditions of the original design are in
doubt in the equivalence shear capacity by the design base shear of
ASCE 7-10 [2] for a linear procedure application, if the differences
in weight, importance, incorrect soil designations, or R value for
the design were used. Again, the users are using the estimated
ratios, not the absolute values of the base shear before and after
consideration of the additional information. The formula has a
power constant that has been determined from empirical damage
data collected from earthquakes in several countries, with a total
of 44 data sets including 31,049 buildings. Key to this development
was damage data for 825 concrete shear wall buildings of the
same configuration, similar design and construction in the 1976
Tangshan, China earthquake for distances from the epicenter
ranging from 1 to 100 kilometers, located in a variety of known soil
types, see TZ [7] for the appropriate damage data demonstrating
this point. In many cases there can be several observed conditions
that could be important to the collapse hazard of the building and
yet not be adequately considered in the P-154 scoring procedure.
In such cases, they can be considered separately or in aggregate.
When considered separately, the aggregate adjustment Δ should
be determined as a product of the 
terms for each
item considered important. Therefore, for the case where the
assessment engineer has a sense for the increased or decreased
damageability, or base shear capacities, when considering the
additional information that was not accommodated in the P-154
value determination, then the impact on the damageability
parameter score 
from these noted points can be directly
determined, as discussed in this section. The impact on the
likelihood of collapse can be determined in exactly the same
way as P-155 suggests, only using the modified performance
score reflecting the additional information available to the
assessor. In summary, when the assessor prefers to use judgement
in terms of base shear, use 
, and when the preference is in
terms of stability damage ratio, use 
. When a modification
is proposed to the 
score, the CB shall consider its basis. After
discussion, each member will be asked to provide her/his best
assessment of the score modification, and the average of these shall be considered as the value. P-154 and P-155 suggest how
to assess these characteristics and how the team decided on the
deduction and addition to the scores. It is useful to study these
in order to understand their basis and assumptions so that their
limitations can be understood.
Determination of Assessment Components for Quality or Reliability
Why is it necessary that the user examine the reliability of a seismic assessment, or for that matter, any technically determined decision on an assigned conclusion of the condition of a civil structure? The principal objective is for life safety; however, for the possible case where future earthquakes may result in unanticipated consequences based on these evaluations, this reliability is required to establish that CSU acted in a prudent manner for the determination of these assessments and the resulting actions. Due to large uncertainties in our understanding and resulting models of earthquake processes and response of complex structures, along with the lack of empirical actual performance data to reduce this uncertainty, expert judgments will always be required in seismic hazard analyses. The evaluation of the Quality or Reliability (measure of uncertainty) of a seismic assessment for an individual building requires a careful identification and consideration of all of the issues, herein termed as components, which can contribute to this uncertainty. For the evaluation of the uncertainty measure for each component in the assessment process, the users are interested not only in the amount and quality of information concerning the technical descriptive characteristics of the component, but also how this information was implemented as represented by the skill, expertise, and experience of the assessor. It is proposed that the most efficient method of characterizing the reliability of the results of an assessment report is by the evaluation of the uncertainty of the individual components of the building assessment, and then combining these uncertainties to quantify the total uncertainty and corresponding reliability of the resulting assessment by the method proposed below. This effort, in essence, is a measure of the epistemic (degree of knowledge or validity of assumed behavior) uncertainty of the assessment result. The following components are important in the assessment of an individual building. Some parts of the components are addressed in the P-154 Forms, but it is desirable for the CB to assess the reliability of the conclusions rather than focus on the scored items themselves. The Decision Standard proposed in Section 5 is based both on the score and a representation of the combined Quality or Reliability of the assessment process (Section 4).
a. Basis of Evaluation - Plans and Reports: Were the original design and/or any modification retrofit documents available for review (likely provided by the campus)? Were these documents sufficient to describe the structural system? If a retrofit was completed, was it consistent with the then currently applicable requirements? Was this retrofit partial or complete? Were there other seismic assessment reports available (also likely provided by campus)? (If so, include copy(s) appended to the P-154 form.) Were all structural modification drawings provided (i.e., do the reviewers know if the entities providing existing drawings know of all of the changes/modifications made to the building since it was constructed)? Otherwise, might there have been changes/ modifications that are not known? See (Table 2), Matrix 1.
b. Basis of Evaluation - Site Visit Inspection: Was the building accessible for the visit? Was it possible to observe a representative number of important structural elements (and potentially hazardous non-structural elements, such as cladding, ceilings, partitions, and heavy equipment, where failure could affect life-safety) in order to verify the as-constructed condition? See (Table 2), Matrix 2.
c. Basis of Evaluation - Personal Qualifications: The qualifications of the assessor performing the assessment is of key importance to the reliability of the conclusions of the evaluation. In addition to the licensing and expertise of the assessor, the degree of experience in seismic performance evaluation is important; ASTM E2026-16a provides a good standard for such qualification requirements (see (Table 2)). For the CSU process, the assigned CB Peer Review Engineer qualifies as a Senior Assessor under this standard. See (Table 2), Matrix 3.
d. Design Basis: What were the seismic design criteria under which the building was designed and/or retrofitted or otherwise altered since construction? This includes the specific seismic requirements as well as the regional standard of practice used (i.e., choice of structural system, extra detailing, evidence of construction quality control, or lack thereof). See (Table 2), Matrix 4.
e. Configuration and Load Path: What are the vertical and horizontal irregularities of the structure using the ASCE 7 designations? Does the detailing of lateral load-resisting system elements accommodate the response effects of these irregularities? Is there an effective load path complete to the supporting foundation material? Does the detailing of the lateral load resisting system provide adequate ductility to accommodate expected demands? What is the potential collapse mechanism? If over-turning tension resistance is required, are there sufficient foundation details to ensure transfer to the supporting foundation material or to tolerate limited rocking? See (Table 2), Matrix 5.
f. Compatibility of Deformation Characteristics: Are the deformational characteristics of the building’s structural and nonstructural elements compatible with the expected seismic drifts? Is there any unintended interference from other stiff elements that could cause failure of critical support elements (e.g., short columns or partial masonry infill in a moment frame system)? See (Table 2), Matrix 6.
g. Condition: Are the structural elements in good condition, damaged, or deteriorated? Are any deteriorated elements important to the seismic resistance and stability? Is there any damage due to past earthquakes, accidents, or fires, and is this damage important to the seismic resistance? Are there any un-authorized modifications (e.g., openings, infills, installed equipment, etc.) that decrease structural resistance or create life-safety hazards? See (Table 2), Matrix 7. The quality of this assessment depends on degree of accessibility to inspect critical structural elements and potential falling hazards. In most cases, this inspection may not be complete because architectural finishes normally conceal important structural elements.
Representation of Quality, Related Uncertainty, and Reliability of an Assessment
The analysis of the reliability of the P-154 assessed 
score
utilizes the methods developed in the peer reviewed paper
Reliability of Seismic Performance Assessments for Individual
Buildings and Portfolios (Thiel, Zsutty, Lee [8]; termed as TZL
below). These methods have been adapted to the task at hand. In
the TZL paper, a procedure was developed for the evaluation of
the quality of the seismic damageability of an individual building.
They were developed based in part as an adaptation of the
procedure introduced in FEMA P-695 [9] for the evaluation of the
reliability of Building Seismic Performance Factors [10]. In this
FEMA publication, the specific problem addressed was the
evaluation of the reliability of a predicted building collapse
displacement under seismic loading. In order to represent the
amount of relevant information and how this information was
implemented in the process of analysis, the following procedure
was proposed. For a given factor of the seven-component used in
the Section 6 collapse estimation process, a quantitative measure
of uncertainty termed as β value: 0 < β <1 was assigned
corresponding to one of three qualitative levels of Quality of
Description of the factor (High, Medium, and Low) and one of
three levels of its assessed Quality of Implementation
Characteristics (High, Medium and Low). FEMA P-695 [9] Section
3.4 presents a simple matrix, shown here in (Table 3), that
provides a single quantitative evaluation of β based on the
paired qualitative assessments of Quality of Implementation
(High, Medium, Low) corresponding to a specific description of
the Quality of Component Description Measure (High, Medium,
Low). Implementation refers to how well the assessor was able to
apply the available information corresponding to the specific
description. The lower the β value, the greater the certainty
(reliability) of the result; conversely, the higher the β value, the
lower the certainty (reliability). For application to the CSU
Assessment process, the means of assigning the required quality
measures are prescribed in (Table 2) which provides matrices for
how the pairs or single expressions of quality for each of the seven
components are to be assigned. Having the pair or the single quality assignments for a component, the corresponding β value
can be found by the respective use of (Table 2 & 4). A statistically
valid approach to combining the uncertainties of the seven
components is by the Root Mean Squared (RMS) value of their
related β values (Table 5). This resulting numerical value of β
(the RMS of the component values) can be expressed as a
qualitative linguistic term by the use of (Table 4) following the
numerical upper and lower bounds. The β values of (Table 4) are
essentially the same as those used in P-695, but with the exception
that P-695 did not provide an assignment of a (Low, Low) entry,
which was added in TZL, and is termed as BAD with a corresponding
assignment of β =1.0 . A most important advantage of being
able to assign a quantitative uncertainty factor 
for each of the
seven components, i, used in an assessment process is that these
quantitative 
values 
can be combined in a
statistically valid method to provide the total uncertainty of the
result of the evaluation. It is important to note that the combinatory
process would be quite subjective if the levels of uncertainties
were to be expressed solely in Qualitative terms. For the proposed
method of evaluating the uncertainty of an assessed score of the
building hazard, the approach described above for the assignment
of qualitative uncertainty expressions by the matrices of (Table 2),
finding the corresponding quantitative 
factors by (Tables 3 &
4), and their RMS combination in Equation 1 below is necessary
because building hazard assessments are based on varying
degrees of available information, professional knowledge, and
related judgements. The expression of the likelihood for building
collapse response due to a given ground motion, or for all possible
site ground motions, and the corresponding degree of uncertainty
is based primarily on the experience and qualifications of the
assessor and the availability of information concerning the
specific characteristics of the building and related seismic hazard.
For a particular building, detailed engineering analyses and onsite
materials testing, and investigation (such as [6] Level 3
investigations) are usually not feasible within available resources.
Also, actual seismic performance data, or damage statistics, for
most existing building types are not sufficient to provide accurate
empirical prediction. Consequently, it is necessary to utilize expert
judgmental qualitative values as a major basis for performance
assessments. At best, these judgmental values are based on the
assessor’s experience and the information obtained from building
construction documents, where available, and/or a building visit
when possible. (Note that for the specific CSU Assessment process,
construction documents are usually available, the assessor is
highly qualified, and a building visit is required.) (Table 4) gives a
simple qualitative ranking based on qualitative terms SUPERIOR,
GOOD, FAIR, POOR, and BAD and their corresponding
(judgmentally assigned) qualitative uncertainty measures ( β
values). The number (five) of the qualitative terms of (Table 4) has
the benefit of being odd such that there is a subjective middle or
neutral representation for judgement heuristics. (Table 2) shows
how the 
values can be assigned where two descriptors,Component Description and Implementation Characteristics are
used (refer to the two column matrices of (Table 2)). (Table 4) is
to be used where only one judgmental Quality choice (refer to the
one column matrices of (Table 2)) is made concerning a particular
component involved in the assessment process. In order to make
justifiable, prudent decisions concerning priorities for allocation
of resources related to the seismic retrofit of deficient buildings in
the CSU system, it is necessary to provide a means of evaluating
the Quality of the assessed 
score. If the Quality is insufficient
for a given building, then decisions must be delayed until improved
information can be obtained. Note again, that for the specific CSU
Assessment process: construction documents are usually
available, the assessor is highly qualified, and the building visit is
required, such that Quality will be GOOD or better. For the CSU
Assessment process, it may be asked, “Why then is it necessary to
evaluate Quality if it is usually GOOD or better? The answer is that
a record of a technically independent Quality Assignment is
necessary for future decisions or performance problems related
to the building. It is important to recognize that the particular
wording of the structural modifiers in the FEMA P-154 [1] Level 2
Form is intended for use by “Civil and Structural Engineers,
Architects, and Graduate Students with a background in seismic
evaluation or design of buildings.” Clearly, even with the P-154
required final review of the Form submittals by an experienced
assessor, the Quality of the resulting assessed Score could vary
greatly due to this wide range of assessor qualifications. With the
condition that the CSU assessments are to be performed by Senior
Assessors defined by ASTM E2026-16a [4], Section 6.2.3.2, see
(Table 1) (e.g., the CB Peer Review Engineer for the campus),
certain modifications are needed to the wording of the Level 2
Form. It is necessary to represent the obvious changes of
description and related scoring that would be possible if it were
given that the assessor was of a Senior Level. These modifications
relate to levels of assigned Quality of Description and
Implementation. For example, a Plan Irregularity Reentrant
Corner condition may exist, but the designer has provided
sufficient details to prevent concentrated damage; or a Soft Story
may be observed, but the columns have sufficient over-strength to
resist failure. These special conditions may not be evident to some
of the generally lower qualified assessors allowed by P-154. The
P-154 Rapid Visual Screening (RVS) process needs to be adapted
to represent the CSU requirements for a Senior Assessor,
Construction Document Review, and a detailed exterior and
interior site visit for the building. The following component
matrices in (Table 2) are to further extend the conditions beyond
the wording of the Level 1 and 2 Forms and allow assignment of
Quality in terms of the description of the availability of information
and how this information was obtained and implemented. These
Quality assignments, and resulting combined RMS value, are not
intended to influence how the P-154 forms are to be filled out but
to reveal to the CSU, as the client, what the uncertainties may be in
the information and methods used for a particular building
assessment. For the specific objective of evaluating the Quality or Reliability of a building assessment, the following procedure will
be used. For each of the seven components of an assessment,
(Table 2) provides descriptive matrices for corresponding
qualitative terms either as a pair of component Quality Measure
and Implementation Characteristics description, or a single
descriptor used for the component evaluation. For a component
having a pair of Quality Measures, the uncertainty measure 
is
found by direct application of the pair of Quality Assignments in
(Table 2). For the case where there is a single Quality Measure that combines the Quality of Implementation within its description,
then Table 3 is used directly to assign the 
value. Essentially, in
these matrices, the assessor can express the Quality of the
available information concerning a building, and how this
information was implemented for the purpose of determining the
applicable items on Forms 1 and 2 and related scores, or reasons
for justifying changes in these scores due to particular conditions
(Table 2).
1. Plans and Reports: Refers to the variety and quality of the information sources on the building used in the evaluation (Table 4a).
2. Site Visit Inspection: Refers to the extent of the physical inspection of the building (Table 4b).
3. Basis of Evaluation-Personal Qualifications: Refers to
the assessor’s experience, knowledge, and other qualifications
to perform the seismic evaluation reliably. Refer to (Table 4) for
direct assignment of 
. Note if a CB member is the assessor, then
this element is given the value Superior (Table 4c).
4. Design Basis: Refers to the level of concern for seismic performance issues prescribed in the Code and Standards used for design of the building or structure. This is an adaptation of Table 3.1 of FEMA P-695 concerning the implementation quality.
The High/High rating is intended to apply to systems that give evidence of having been designed specifically to provide “backup or dual systems”, redundancies intended to guard against unanticipated failure modes, and/or specific extra details to ensure a reliable capacity to resist cyclic inelastic loading due to hazard of site ground motion. The QUALITY assignments refer to “how well” the assessor was able to determine the design characteristics by review of construction documents and the site visit (Table 4d).
5. Configuration and Load Path: Refers to irregularities in the configuration and/or discontinuities in the load path of the lateral load-resisting system and how well or poorly the design addresses these irregularities in order to provide acceptable seismic behavior (e.g., acceptable low risk of collapse due to hazard of all levels of site ground motion, see Section 5). Concerns the Vertical and Plan Irregularity Items in P-154 Level 2 Form. The Quality assignments refer to “how well” the assessor was able to determine the configuration characteristics by review of construction documents and the site visit. The focus of this element is to determine if there are ASCE 7 irregularities in the load path and whether these are important to characterizing the expected collapse characteristics of the building. If the detailing is adequate, then the assessor can have high, moderate, or low confidence in how the building will perform and how this impacts the reliability of the collapse assessment of the building (Table 4e).
6. Compatibility of deformation characteristics: Refers
to the stiffness compatibility among all structural elements’
earthquake loads. It is intended that both the ASCE 41 S5 in
BSE-C and S-3 in BSE-R performance be assessed, with the most
restrictive result applying. Refer to Table 3 for direct assignment of
. The Quality assignments refer to “how well” the assessor was
able to determine the compatibility of deformation characteristics
by review of construction documents and the site visit (Table 4f).
7. Condition: Refers to the physical condition of the
building, particularly the structural elements and connections of
lateral load resisting systems, the foundation (where observable),
and how the observed condition may affect the expected seismic
performance of the building. The intent is to focus on signs that
the lateral load-resisting system may be impaired. However, if
there are conditions that have a significant effect on the vertical
load bearing system, these would probably be triggered by seismic
displacements, and should be reported. Note that this “Condition”
component relates to the results of the Site Visit Component 2.
Refer to Table 3 for direct assignment of 
. Concerning the
“observable damage or deterioration” see item of P-154 Level 2
Form. Where the observed or inferred conditions cause serious
weakening of the seismic performance that could contribute to
collapse possibility, then these should be noted on the Comments
sheet with recommended score modifications if appropriate. The
Quality assignments refer to “how well” the assessor was able to
determine the condition characteristics as a result of the site visit
(Table 4g).
NOTE: Particularly applicable conditions may not be appropriately described and scored by the Topics listed on the Level 2 Form. The assessor shall use the supplemental Comments Form to: describe these conditions, recommend an appropriate Topic change and score modification, and provide a Quality assignment for the related additional information.
some cases, it may not be clear that definitive choices can be
made in the (Table 2) Measure and Implementation assignments.
For example, the assignment is mid-way between High and
Medium, or the probability of High and Low are each 25% and
the probability of medium is 50%. In other words, there is
legitimate doubt in which assignment is appropriate. If the user
designates the probability of the Quality Measure as 
for
the three Measures j = H, M and L , and as probability
for the Implementation Characteristics, and 
be the
corresponding β value in (Table 2) for row j and column k ,
then the appropriate combined value is determined as:
where 
is the value entry in (Table 2) for the appropriate
matrix location. This weighting approach is used to determine
the assigned value since the users are, in essence, interpolating
between the b values of the component matrix. (Table 4) shows
what these values look like for several different assumptions on
the probabilities of both Quality Measure and Implementation
Characteristics. These numerical values should be used in the subsequent analysis, not the linguistic equivalents of (Table
5). It is also important to recognize that (Table 2) provides the
means of expressing a quantitative measures expression of a
quantitative value of a numerical β value. There may be cases
where decision makers may prefer to express their judgements
to their peers in qualitative terms. Similarly, users, particularly
for non-technical audiences, may feel more comfortable or
effective in using these qualitative terms for the justification of an
economic decision rather than quantitative values, which would
require more explanation and possibly result in confusion. Our
goal is to use these sets of quantitative and qualitative terms to
describe the Quality, reliability/uncertainty of the assessment
results. (Table 3) provides guidance on how to assign quantitative
β values according to the pairs of qualitative expressions for
component Description and Implementation Characteristics as
obtained from the (Table 2) component matrix evaluations. The
β values are considered as measures of uncertainty (in terms of
the standard deviation for error ranging from zero to unity) and
serve to indicate higher reliability as the lower the β value, and
the converse, the lower the reliability as the higher the β value.
An important advantage of the quantitative βi
values for each
component is that the total uncertainty β value assignment may
be evaluated in a statistically consistent procedure as discussed
below. Rationally, it would not be possible to express the Total
Uncertainty as a combined effect of a set of different qualitative
terms, except perhaps by assigning the most prevalent value,
which is not very compelling. It may be instructive to see how
different arrays of 
values contribute to the total uncertainty
of the β value assignment. (Table 6) shows the impact on β
of having all the 
values the same except one, two or three
(denoted by 
) that have assigned the same value, possibly
different from the fixed value. Note that achieving a GOOD rating
does require most, but not all, of the ratings to be GOOD or better.
If one is POOR, then all the rest have to be GOOD or better, and
if three are FAIR, then the rest have to be GOOD or better. In the
Decision Rule developed in the companion paper, CSU and the SRB concluded that the reliability of the assessment would have
to be β ≤ 0.30 to be actionable It is instructive to note that the
elements for a conventional P-154 assessment as shown in (Table
2) indicates that items 1, 2 and 6 are highly likely to be POOR or
higher without the review of documents and performance by a
highly skilled assessor, which yields β = 0.34 if the balance are
all Superior, which is highly unlikely [11].
Determination of reliability/uncertainty value β for an individual building assessment
The determination of the reliability for a specific building’s
assessed score 
requires a statistically consistent manner of
combining the individual component uncertainties, 
, in order
to reach an aggregated value, β , as a measure of uncertainty for
the building assessment process. The users are dealing with the
subjective assignment, by the designated assessor, of the quality
and corresponding quantitative 
value for each component of the assessment process. The information obtained from each
component is represented as score modifiers in the P-154 Level
1 and 2 Forms and associated Comments. Since the final assessed
score 
is the result of an additive process, the most appropriate
method of combining the associated subjective uncertainties, 
, is to consider them as the “standard deviations” of error such
that 
is the variance of error. If the users tacitly assume that
the assigned qualities are independent for each component, then
the combined variance is the “sum of the component variances”
(essentially, independence may not be completely valid: for
example, the Quality of some components depend on the Quality
of the completeness of the design documents; however, the effect
of the neglect of any covariance contributions are minor when
compared to the variability of the judgmental assignments of
Quality). Also, in order to ensure that the combined β value,
shown below, remains between 0 and 1 such that (Table 4) can
be used for the qualitative description of this mathematical
(quantitative) result, it is necessary to divide the combined
variance by the number (7) of components. In some cases, not all the seven components of this document will be important to the
evaluation, and there are likely to be others that are not in the
group that are vital; therefore, assume that there are n items. The
resulting aggregated value, β , is the Root Mean Squared (RMS)
value:
This method of uncertainty combination is consistent with
the accuracy of the assigned uncertainty values in (Tables 1
& 3). It is assumed that each of the uncertainty components,
, have equal importance such that no weighting factor is
required for components. Note that the division by the number
n of components achieves the desired result that if all the 
values are the same, then the aggregated β is the same as each
of the individually equal values. The value of β determined from
Equation 2 is the assessed reliability parameter for the assessed
building which will be at the core of the companion paper
procedure for determining whether the assessment performed
value of 
is actionable [12].
CSU Application Experience
CSU assessed the seismic vulnerability of 56 buildings and one
building-like structure (providing vertical access among buildings,
Building A17) on three campuses in 2021 using the procedures
recommended in this paper. The Vice-Chair of the SRB served as
the chair of the assessors committee, and the SRB served as the
equivalent of the CB as recommended here. (Table 5) presents
the results of these assessments and their reliability assessment
components. As can be seen, the persons doing the assessments
were highly qualified structural engineers. All had 30 years or
more experience in designing and assessing California building
construction and were assigned as campus independent technical peer reviewers for all construction on their respective campuses
by University Policy. The 56 structures assessed were constructed
from 1922 to 1994, with an average date of 1968. The SRB was
given authority for independent building plan technical review
for modifications of existing buildings in 1993; this authority
was not extended to new buildings until 1994 but did not apply
to construction already in progress. Since all new construction
initiated after this date and all new purchase of buildings since
that date have been reviewed for acceptable seismic safety before
purchase and was independently peer reviewed by the SRB,
there are likely to be no buildings of more recent age evaluated
under this program. The typical report of the P-154 assessment consisted of the two form pages, added discussion of the assessor’s
observations, and often a few images from the design drawings. The
average length of the report was 3.75 pages, without illustrations
and copies of details of construction, with many having limited
added comments because the case was so clearly evident that the
building was either not highly hazardous on its face or not in doubt
for its hazard. When these were assessed, the full team had access
to the design structural drawings for reference and discussion.
The assessors chose not to adjust the 
values but to discuss
their observations with the group and assign each structure to
a List based on this discussion. The group’s 
average value
was 1.18, and it ranged from 0.20 to 3.0; 50 were less than 2.0,
which was the P-154 original method required detailed seismic
analysis. Only two were placed on List 1 and 12 on List 2. As can
be seen by the values, the quality rating for Elements 1, 2, and
3 were all superior in average (average 0.107, 0.102, and 0.100),
reflecting the high qualifications of the assessors. The values for
element 4 (Design Basis) and 5 (Configuration and Load Path)
were 0.364 (Sigma 0.143) and 2.51 (0.143) and indicative that
many of the buildings were pre-modern seismic design practices
and that modern load-path requirements were irregularly
followed when they were designed. The compatibility of all the
buildings was SUPERIOR (0.10). The resulting Reliability value
average was 0.198 (GOOD) with a standard deviation of 0.055 and
a range of 0.100 to 0.359, with only one exceeding the acceptable
limit of 0.300, which was the non-building that was assessed.
Of the 56 buildings assessed, the Decision Standard yielded the
same result in all but 6 cases, for an 89% validity rate. The SRB
originally recommended an acceptability reliability rate of at least
GOOD, with maximum value by (Table 4) of 0.275. The SRB made
this assignment before it had experience with the procedure.
When they had the results discussed above and given in (Table
7), they had the basis for adjusting the upper bound acceptable
score value. There were seven cases where the reliability value
was above 0.275, with six values between 0.280 and 0.288. When
the sources of the uncertainty were examined, it was decided
that the likely performance was adequate, and the SRB changed
the upper bound for acceptability from Good to 0.30. There
was one value of 0.359 for the non-building structure, which
was recommended for action by CSU to assess immediately at
a higher level of investigation. It is advisable that the decisions
made under this, the Decision Rule, be examined for consistency
with good practice, and it is not viewed as an absolute rule for
decision making. As a final observation, the application of the
proposed approach is evaluated by CSU management costing
about $2,500 per building, including assessor time, travel, and
expenses, as well as the assessors’ discussion of their results prior
to the SRB assessment. The SRB time was minimal and attributed
to their regular meeting efforts, which covered this as well as
other subjects. It is interesting that of the 56 buildings assessed
in (Table 7), all but four had 
values lesser than 2.00. In other words, P-154 would require detailed seismic evaluation to
decide how to proceed. The modifications of the RVS procedure
developed for CSU reduced this to two buildings put on List 1
requiring near term seismic evaluation, and 12 buildings on List
2 requiring evaluation when any permitted work was proposed,
and the balance awaiting proposal of permitted work that the
CEBC would trigger seismic evaluation. The assessors noted
that the individual assessors made no adjustments to the P-154
scores. Instead, the scores were recorded as consistently as
possible with the P-154 instructions, even if a particular score did
not necessarily reflect the significance of a particular issue. The
assessors summarized instances as additions to the P-154 Forms
where they believed certain scores incorrectly underestimated or
overestimated the significance of a given issue. These summaries,
in addition to the scoresheet, formed the basis for the review
committees’ deliberations as to whether a building belonged on
one of the seismic priority lists or on no list. In a few cases, P-154
score interpretations were changed, but this was reflecting
a different interpretation of the scoring statements by the review
committee from that taken by the original assessor. These
recommended changes were ultimately accepted by the original
assessor. Although the decision rule had not been formalized at the
time the assessments were performed and discussed, enough was
known about the proposed rule to generally guide discussions and
recommendation by the review committee. List assignments did
not follow the Decision Rule in all instances, but these deviations
were limited and substantiated by the professional judgment of
the original assessor and the review committee. The SRB did not
alter any recommendations presented [13].
In summary, the principal impact of the Modified P-154 process
is that the decisions it yielded conformed with a level of reliability
that was acceptable to CSU management and their advisors. This
suggests that the basic structure of the P-154 process is sound,
and that when modified as recommended in this paper, yields
good decisions that are reliably based when they are reviewed in a
consistent manner. However, if the client is interested to the P-154
determination of identifying which buildings warrant an ASCE 41
[3], Level 3 (or lower) assessment, then it can be used to advantage
unchanged. We would recommend that for such applications the
triggering remains, since there is high uncertainty in
the reliability for the resulting assessment as reflected by poorer
reliability of the assessment using the methods of this paper.
This process was evaluated by the CSU, SRB, and Administration as appropriate to succeed the prior procedures and to yield a consistent, transparent, and documented assessment process. CSU has recently begun its second and in advanced planning for the third annual evaluation efforts and has committed to its continuing use as its evaluation metric, with annual reassessments by the SRB to refine the effectiveness and reliability of the process.
Conclusion
One of the difficulties with most seismic hazard assessment procedures is that the results of an assessment are binary; that is, they either meet the evaluation standard, or they do not. The evaluation is usually approached based as a scenariobased event, often the MCER, 475- or 2,475-year return period events. For owners of individual or large portfolios of buildings, the cost implications of these binary outcomes are likely to demand significant resources to resolve. A key issue in seismic management is to determine whether the reliability of the seismic assessment is sufficient to warrant action. This paper has focused on this issue so that there is a procedure that can be easily applied to determining whether the conclusions were found based upon adequate information and technical skills of the assessor. It is no longer necessary to have blind, untested faith in the reliability of an assessment. A great advantage to the proposed method of reliability assessment presented is that is can be easily modified to any series of uncertainties in (Tables 3 & 4) that properly reflect a given client’s requirements. The procedures then will reflect the client’s needs for differentiation among actions required.
Acknowledgement
The reviews and comments of the CSU SRB made during the development of this assessment and its testing are greatly appreciated. These include Thomas Sabol, Ph.D., SE, Richard Niewiarowski, SE, Maryann Phipps, SE, Barry Schindler, SE, Dirk Bondy, SE, John Egan, GE, and Trailer Martin, SE. Members of the CSU Chancellor’s Office assisted in setting the goals for the procedure and in reviewing its applications. They include Jack Andersen, AIA, NCARB, Paul Gannoe, Ebi Saberi, AIA, and Elvyra F. San Juan, Assistant Vice Chancellor Capital Planning Design and Construction, who posed the problem, which the authors proceeded to resolve with the approach to ranking buildings for seismic retrofit presented in this paper. I am sorry to report that my coauthor, Theodore C. Zsutty, died in the last week of April after a long and productive life to his end at age 92, before this paper’s submission, but after it was in essence completed. He was an active member of the structural engineering community as a professional engineer, professor, researcher, code and practice developer, peer reviewer, and advisor to many designers and participant in their resolution of technical problems. He and I have authored many papers together since the 1980s. He was a respected, energetic and highly competent engineer and thinker. He will be missed by all with whom he worked.
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