Structural Condition Assessment: - Conference Planning and ...

ASCE STRUCTURAL ENGINEERING CONFERENCE
Iowa Section of the American Society of Civil Engineers & Iowa State University
Ames, Iowa, November 2, 2009
Structural Condition Assessment:
Why? What? How?
Robert T. Ratay, Ph.D, P.E.
www.RobertRatay.com

O U T L I N E
Part I
Overview
Why condition assessment?
What can be wrong?
What is structural condition
assessment?
Types of condition assessment
Qualifications
Codes, Standards, Guides
References
Part II
Practice and business
The call
Assurance of public safety
Inspection & documentation
– Team
– Field equipment
– Field activities
– Field documentation
Preliminary conclusions
Report(s)

O U T L I N E
Part I
Overview
Why condition assessment?
What can be wrong?
What is structural condition
assessment?
Types of condition assessment
Qualifications
Codes, Standards, Guides
References
Part II
Practice and business
The call
Assurance of public safety
Inspection & documentation
– Team
– Field equipment
– Field activities
– Field documentation
Preliminary conclusions
Report(s)

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Part I
Overview

Somewhat like people
Structures, like people,
– get older
– need check-ups
– get sick
– need treatment when ill
– may even be placed on life-support

Somewhat like people
Structures, like people, can maintain their good
health with age
– if properly cared for
– examined
– treated when needed

Why condition assessment?
To examine and diagnose for
– sale and purchase of buildings
– needed maintenance
– repair and rehabilitation
– adaptive reuse of facilities
– retrofitting for ever-changing code compliance
– increased physical security

Defect
What can be wrong?
– errors in design, poor construction, defective materials
Deterioration
– degradation in performance with time
Damage
– natural, deliberate or accidental event

What can be wrong?
All structures deteriorate with time as the result of
– repeated loadings
– exposure to the elements
– aging of materials
– wear-and-tear
– abuse
– inadequate maintenance
– other reasons

What can be wrong?
Structures may also be unwell on account of
– errors in their original design
– shortcomings in their construction, or
– imperfections in their materials

What is structural condition assessment?
Structural condition assessment is the physical
examination and diagnosis of the “health” of a
structure
It may include one, several, or all of the activities of
– visual observation
– measuring
– photographing
– probing and sampling
– field and laboratory testing
– numerical analyses
– record keeping
– documentation
– report preparation

Types of condition assessment
Walk-through
Due-diligence
Structural integrity / in-depth

Types of condition assessment
Walk-through – walking through the facility, observing
what is readily visible, and opining on the general
condition of the facility.
Due-diligence assessment – in essence, a cursory visual
inspection of the facility, looking for and identifying
clearly visible deficiencies, and reporting on the overall
condition with a list of the obvious existing and potential
problems, if any.
It may be followed by a more thorough examination of parts or all of the
structure.
Structural integrity assessment – an in-depth examination
of the facility including some or all of the following
activities
– visual observation
– field measuring, photographing, probing and sampling
– field and laboratory testing, numerical analyses
– checking code-compliance
– documentation
– report preparation

Qualifications
Understanding of structural behavior, and working
knowledge of structural analysis and design
Experience in field observation of structural
problems
Thoroughness in field measurements, testing and
analyses
BUT ability to interpret data and make engineering
judgment to convert them into valid conclusions and
recommendations are most important

Qualifications
The engineer who undertakes condition assessment
of a structure needs to know
– how to plan and organize the process
– how to inspect the structure
– what to look for
– how to recognize various conditions
– what methods of field examination, laboratory testing,
analytical evaluations are available, feasible and useful
– what to recommend
– how to report the findings

Practice and business
Professional practice within the field of structural
engineering
A more-and-more active business

ASCE Guides
Codes and Standards
ASTM Standards
International Existing Building Code

ASCE Condition Assessment Guidelines
SEI/ASCE 11-99, Guideline for Structural Condition
Assessment of Existing Buildings, American Society of
Civil Engineers (ASCE), Reston, VA, 1999
Revised edition 2009

ASCE Condition Assessment Guidelines
SEI/ASCE 30-00, Guideline for Condition Assessment
of the Building Envelope, American Society of Civil
Engineers (ASCE), Reston, VA, 2000

ASTM Standards
ASTM E2018, Standard Guide for Property Condition
Assessments: Baseline Property Condition Assessment
Process, Annual Book of ASTM Standards, ASTM International,
West Conshohocken, PA
(Defines “expected useful life” same as “design life”)

International Existing Building Code
International Existing Building Code, International Code
Council, 2009

New York State Building Code
Building Code of New York State, Chapter 34,
Existing Buildings

Two books on structural condition assessment,
and engineering response to failures
Publisher John Wiley & Son, 2005
Publisher McGraw-Hill, 2000
2 nd Edition 2009

Conference, Journal, Magazine Articles
Proceedings of 2006 Structures Congress May 18-21, 2006, St Louis, MO
“Professional Practice in Structural Condition Assessment”
Condition Assessment of Structures
Why Structural Condition Assessment?; Robert Ratay
Buildings; David Peraza
Parking Structures; Peter Popovic, James Donnelly, Brian Pulver
Stadiums and Arenas; Thomas Scarangello, Glenn Thater, Leonard Joseph
Condition Assessment of Materials
Durability and Service Life; Andrea Surovek, David Nicastro
Steel; Robert Vecchio
Concrete; Scott Wolter
Masonry; David Transue
Timber; Donald Neal

Conference, Journal, Magazine Articles
Ratay, R. T., Preventive Medicine: Condition Assessment, Editorial,
Structural Engineering International, IABSE, 2/2007
Vecchio, R. S., Condition Assessment of Steel Structures, STRUCTURE
Magazine, November, 2006
Structural Condition Assessment: The Good, the Bad and the
Inevitable (Ugly?) STRUCTURE Magazine, August, 2006
The Good – Overview, R. T. Ratay
The Bad – Strategies for Condition Assessment, D. B. Peraza
The Inevitable – Assessing Liability, M. Zetlin & C. Fladgate

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Large Property Owners’ and Managers’ Guides

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End of Part I
Overview

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Part II
Practice and Business
Damaged Buildings

O U T L I N E
Part I
Overview
Why condition assessment?
What can be wrong?
What is structural condition
assessment?
Types of condition assessment
Qualifications
Codes, Standards, Guides
References
Part II
Practice and business
The call
Assurance of public safety
Inspection & documentation
– Team
– Field equipment
– Field activities
– Field documentation
Preliminary conclusions
Report(s)

.
The Call and then . . .

When The Phone Rings
Who is calling ?
– Owner
– Insurance company
– Attorney
– City or State authority

When The Phone Rings
It may be urgent
It may be exploratory
It may just be fishing for free information

Catastrophic Failure?

.
Partial Collapse?

.
Impending Collapse?

.
Localized Failure?

.
Sign of Distress?

Contract / Agreement
If time allows, written agreement
Scope of Assignment
Fees & schedule of payments
Hold Harmless, Indemnity, Limitation of Liability
Insurance

Contract / Agreement
If time allows, written agreement
Scope of Assignment
Fees & schedule of payments
Hold Harmless, Indemnity, Limitation of Liability
Insurance
If no time, oral agreement
Scope of Assignment
Fees

Assurance of Public Safety

Immediate Preliminary Assessment of Threat
To the public
To public property
To utilities
– Mass transit
– Communications
– Power
Sanitary Conditions
Hazardous materials
Pollution
To private property

Immediate Response /Action
Restrict Public Access ?
– Single building
– Neighborhood
Stop adjacent construction ?
Stabilize ?
Demolish ?
Protect ?
– Barricade
– Netting to contain debris
– Sidewalk bridge to shield
.

.
Protection
Netting
Bracing
Shoring
Sidewalk
shed

Risk versus Reward
Likelihood of threat materializing ?
Potential consequences ?
– Of doing nothing
– Of doing something
…Must err on side of caution

Risk versus Reward
Rapid decisions may be needed
Available information is incomplete

Resist snap judgment
If no time to analyze
First Impressions
– Edit out unimportant observations
– Balance between instinctive and deliberate thinking
– Make intuitive judgment
– Resist publicizing your intuitive judgment
Don’t get locked-in

Field Inspection &
Documentation

Equipment
Appropriate clothing
Hard hat
Safety glasses
Phone
Camera
Tape measure
Markers
Pen, color pencils
Writing pad (scaled)
Flash-light
Hammer, screwdriver pocket knife
Carpenter’s level
Binoculars
.
Remember Personal ID

Special Test Equipment, if
Crackscope (microscope w/built in scale for crack width measurement)
Windsor probe (for concrete strength)
Chain drag (for concrete delamination investigation)
Pachometer (for rebar location)
Moisture meter (for moisture content in wood)
Radiographic equipment (for locating discontinuities and voids)
.

First Activities
Get oriented
Look at plans, if available
Record and document existing conditions
– Take photographs
– Make measurements
– Take notes
Preserve perishable evidence
Reserve samples
Interview witnesses
Speak with other investigators
Do not talk to media or reporters
Do not make hasty conclusions
Remember: You may never see this same condition again!

Get Oriented
Walk around
Walk through
Note the obvious

Photographs
Videos (?)
Sketches
Measurements
Observations
Record Visible Conditions

Photographs
Take lots of them … film is cheap! … digital is limitless!
Keep log of photographs
For each photo record
– Roll ID or filename
– Photographer name
– Date taken
– Short description or caption
– Set date stamp feature

Photo Tips
Make photos as self-explanatory as possible
– Take context / panoramic photo, then close-up
– Label components, highlight features
– Place an object for scale (tape-measure, coin, vehicle, etc)
– Mark location on a key plan

Photo Tips
.
Close-up
Context

Photo Tips
Orientation
Context
Close-up

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Photo Tips

Give a sense of dimension
Photo Tips

Video
Suitable for video recording
Activity or process
Walk-through
Where note-taking is difficult

Video
Disadvantages
Can be amaturerish
– shaking
– excessive panning
– background noise
Need special viewing equipment
If warranted, consider using a professional

Preserve Perishable Evidence
Collapse configuration
and remaining structure
– Telltale signs(?)

Preserve Perishable Evidence
Snow and/or ice loads

Fracture surfaces
Preserve Perishable Evidence

Reserve Samples
Deformed, deteriorated, failed components

Detached/fallen pieces
Reserve Samples

Reserve Samples
Intact components
– As examples
– For close examination
– For comparison to drawings
– For comparison to failed components
– For testing
– As proof that the component did not fail

Make Probes
To expose hidden conditions

To record damage
Look Inside To Suspect Areas

Install Monitors
For prolonged observation and record of continuing
movement

To confirm concrete
strength
Take Concrete Cores

.
Perform Field Load Test (Later?)

Can be valuable
Can be conflicting
The sooner the better
Interviews
– Fresh
– Unbiased
– Helps locate other witnesses
– Helps formulate hypotheses

Field Notes
Field notes are irreplaceable first-hand records
Should be clear, self-explanatory, legible, accurate,
organized, dated, authored
Should include
– Activity log
– Sketches
– Measurements
– Reference to photographs
– Conversations
– Instructions given
– .

Preliminary Conclusions
VERY IMPORTANT! BEAWARE!
Resist snap judgment
Be careful with intuitive judgment
If no time to analyze
– Edit out unimportant observations
– Balance between instinctive and deliberate thinking
– Resist publicizing your intuitive judgment
Don’t get locked-in to a conclusion that may
change after later engineering analyses

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Reports

Report
On-site oral report to client (?)
Initial written report
Final report

On-site Oral Report to Client (?)
Decline, if not ready to opine
Emphasize degree of certainty
Explain reasons for uncertainty, if any
Do not mislead
Do not try to please
Explain what more work is needed

Written Report
The documentation of a structural condition
assessment is the written report.
The work is incomplete, and of questionable value,
until a written report is rendered.

Initial Report
Background
– Reason for condition assessment, dates, names
Description of Structure
– Location, size, usage, vintage, history, structural system
Site Observations
– What was/not inspected and how
– What was found
– What more needs to be done
Initial Evaluation
– Evaluation of all information gathered
– Rationale behind conclusions and recommendations
– Limitations and restrictions imposed
Preliminary Conclusions and Recommendations

Final Report
Simple one-or-two-page letter
Multi-volume set of documents
Consistent with the scope and extent of the project

Letter Report
A letter report is often adequate and appropriate
– Date
– Addressee
– Reference
– Salutation
– Introductory paragraph
– Purpose and scope of work
– Materials reviewed
– Description of the structure
– Findings
– Conclusions and recommendations
– Sign-off and signature
– Enclosures, if any

Formal/Final Report
A reasonable organization of a large formal report may be the following:
– Cover page
– Title page
– Table of contents
– Executive summary
– Introduction (background, purpose, scope of the work, qualification of the team)
– Description and history of the structure
– Governing codes and standards
– Documents and information reviewed and used
– Methods and equipment used
– Field inspection and observations
– Probes
– Field and laboratory testing
– Structural analyses and results
– Evaluation of field and analytical findings
– Summary
– Conclusions
– Recommendations
– Disclaimer
– Photographs and Figures
– Appendices

Appendices to Report
• Photographs
• Sketches
• Field Notes
• Useful “garbage”

CASE Report Guidelines
National Practice Guidelines for the Preparation of
Structural Engineering reports for Buildings,
Council of American Structural Engineers (CASE),
Washington, DC, 1995

Reminders for The Report
Beware of pronouncing the structure “safe.”
Safety or the lack of safety of a structure is not
inherent but rather it is an opinion based on
observations, calculations and tests,
all of which may be performed and judged
differently by different investigators.
In addition, “safe” for a particular exposure, use or
load that is known may not be “safe” for another
exposure, use or load that is either known or unknown.

Reminders for The Report
Be sure to point out any limitations and restrictions on
your work whether by instructions from the client, or
on account of restricted time, money, access, or other
reason.

Reminders for The Report
Present a list, or at least an overall description, of
those structural items which were not inspected on
account of lack of access, time, money or other
reasons; and opine whether special effort should be
made to inspect them.

Reminders for The Report
It is not unreasonable to write a well-considered and
carefully worded disclaimer to limit your liability to
the specific intent and content of the report.
It may be advisable to alert the client at the outset of
the project that the report will have a reasonable
disclaimer.

Reminders for The Report
Be aware that your condition assessment report may
have serious financial and legal consequences to the
client!
At the same time, however, be mindful of your
responsibilities for public safety.
And do not lose sight of your own professional
responsibilities and legal liabilities!

Enjoy your afternoon!
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