The Structural Engineers Association of Illinois is pleased to announce the SEAOI 2021 Virtual Forensic Forum! The event provides an opportunity for structural engineers to share best practices, lessons learned, and new techniques related to the investigation of failures or other performance problems. Failures are not all catastrophic, such as when a building or bridge collapses, but include facilities or parts of facilities that do not perform as intended by the owner, design professional, or contractor. Forensic design and construction topics will be presented by a diverse group of engineers from Chicagoland and beyond. The Forum is designed for all structural engineering professionals interested in forensic engineering.
June 3, 2021
|12:00pm- 1:00pm||Residences at Water Tower - Marble Facade Restoration
William D. Bast and Lee Fink, LPI, Inc.
|1:00pm - 2:00pm||T2D2: Computer Vision for Detection, Classification and Monitoring of Facade Damage Conditions
Rachel Michelin and Badri Hiriyur, Thornton Tomasetti
June 10, 2021
|12:00pm - 12:30pm||Failure stress of glass made easy. Or is it?
Terrence McDonnell, Klein and Hoffman, Inc.
|12:30pm - 1:30pm||Large Scale Parking Structure Vehicle Fire Damage Evaluation and Restoration
Alex Katz, Walker Consultants
|1:30pm - 2:00pm||Preserving the Beauty of Cast Iron During a Forensic Analysis
Allison Toonen-Talamo, Klein and Hoffman, Inc.
June 17, 2021
|12:00pm - 12:30pm||Case Study in Service Life Prediction of a Post-Tensioned Concrete Parking Structure
Joseluis Alvarez, Thornton Tomasetti, Inc.
|12:30pm - 1:30pm||Understanding Wood Moisture Movement in Diagnosing Problems with Wood-Frame Structures
Leonard J. Morse-Fortier, Simpson Gumpertz & Heger Inc.
|1:30pm - 2:00pm||Forensic Analysis of Failures in Plumbing Pipe
Alan Humphreys, Simpson Gumpertz & Heger Inc.
June 24, 2021
|12:00pm - 1:00pm||Precast, Prestressed, and Well Done
Thomas Frankie, Wiss, Janney, Elstner Associates
|1:00pm - 2:00pm||Grain Terminal Silos | Hopper Collapse and Silo Wall Distress Investigation
Stephen Schmitt Jr., and Timothy Fitzgerald, Wiss, Janney, Elstner Associates
8 Credit Hours
- Member - $360
- Non-Member - $450
Zoom is offering live closed captioning to users through Fall 2021. If you want it, you need to complete a request form here.
About the Speakers
William D. Bast, P.E., S.E., Principal and Senior Consultant
Bast is a Principal with LPI, Inc.'s Chicago office and has over 35 years of experience as a structural engineer in Chicago. His project work includes Wrigley Field Restoration, Navy Pier Reconstruction Project, and Willis Tower Repositioning. He is a Past President of SEAOI and NCSEA.
Lee Fink, Senior Consultant
Fink is a Senior Consultant in the Building Envelope Division of LPI, Inc. in Chicago, Illinois. His areas of expertise include design and restoration of building enclosures which include curtain wall, glazing, metal cladding, masonry wall, and roofing systems. He is chair leader on the Technical Issues Knowledge Committee for the American Institute of Architects (AIA Chicago) and had previously served as an adjunct professor for the High-Performance Building Design course at Northwestern University.
Residences at Water Tower - Marble Facade Restoration
Water Tower Place is a 74-story building constructed in 1976. The exterior façade is generally constructed of 1-1/2 inch thick Georgia Cherokee Solar Gray marble stone veneer panels, with flush aluminum framed windows. The panels are typically restrained using stainless steel kerfs at the bottom corners or center of the panels, and stainless steel pins at the top and sides of the panels.
In December 2003, the Owner was advised that bowing of the marble façade panels and presumed accompanying marble strength loss had accelerated after 25 years of slow but linear weakening.
In 2006 a custom anchor was developed for use on the building, rather than using the helical anchors or expansion anchors employed in previous repair campaigns. In October 2007, based upon wind tunnel results and the custom anchor specifications, the first of approximately 16,800 custom anchors were installed. The anchor installation continued through 2008 and was completed in the summer of 2009. These anchors are designed to resist wind pressure or suction only (not gravity load) and were positioned within the spandrel and column panels to limit flexural stresses to either 224 psi in the main field of the stone away from support conditions, or 393 psi near the stone kerfs, pins, or anchors.
Since 2009, additional marble testing has been performed, and closehand facade examinations conducted to evaluate the performance of the anchors and the degradation of the marble.
This presentation will summarize the findings and conclusions to date.
Rachel Michelin, AIA, LEED AP BD+C
Rachel Michelin, AIA, is co-director of Thornton Tomasetti’s Chicago Office and leads a consulting group focused on building envelope improvement and renovation projects. She has provided forensic expertise and design solutions for buildings of all sizes, vintages and, construction types.
Badri Hiriyur, Ph.D.
Dr. Badri Hiriyur is a vice president and director of artificial intelligence at Thornton Tomasetti, as well as the founder and CEO of T2D2.ai. Dr. Hiriyur leads the CORE.AI research and development group focused on developing applications that leverage artificial intelligence and machine learning to transform workflows and processes in the AEC sector.
T2D2: Computer Vision for Detection, Classification and, Monitoring of Façade Damage Conditions
Damage and deterioration can occur at any time and at any location of a structure. Detecting and monitoring all of these conditions have traditionally required extensive scaffolding or specialized equipment, which is intrusive and expensive, especially on large structures. Today, drones and other advanced robotics have enabled us to visually capture the state of every square inch of our property in a cheap and efficient manner. However, this usually results in a profusion of data. How do we make sense of it all? Fortunately, advances in computer vision have enabled machines to do this at scale in an efficient, robust, and repeatable manner. In this talk, we present T2D2, which implements state-of-the-art computer vision models to detect and classify damage conditions in structures. It provides a cloud-based web portal to host the digital twin of a building asset to enable continuous monitoring of these conditions.
Terry McDonnell, PE, SE, PEng, SECB, Principal
Klein & Hoffman
Terrence R. McDonnell combines practical structural engineering expertise to understand modern advancements in the building industry, committing every day to find new and innovative ways to turn his clients’ ideas into reality. He leads multi-disciplinary project teams to deliver cutting-edge solutions on many building types, including commercial office, education, hospitality, health care, sports and entertainment, transportation, and more. Terry has a passion for pushing the boundaries of structural glass and acrylics, conducting forensic investigations and conditional assessments, designing high-rise and long-span structures, and performing adaptive re-use.
Terrence is active in the architectural and engineering communities, both in the Chicago area and at the national level. He participates on the City of Chicago high-rise committee and the ASTM E06 Committee on the use of glass in buildings and the design of glass pools and aquariums. He is a past president of the Structural Engineering Association of Illinois, a former board member for the American Society of Civil Engineers Sustainability committee, and was named one of Building Design + Construction’s “40 under 40” in 2011.
Failure stress of glass made easy. Or is it?
Glass fracture investigation primarily originated from Griffith (1920). Evolutions of his theories regarding the probabilistic failure of the material led to the glass failure prediction model (GFPM) by Beason and Minor. Today ASTM E1300, Standard Practice for Determining Load Resistance of Glass in Buildings, is mainly based on the Glass Failure Prediction Model. This comprehensive model should determine stress at failure and its check versus a limit state, a straightforward procedure. Yet it is not. A failure limit state remains undefined within existing standards.
This presentation will briefly review the history of glass fracture numerical formulations for soda-lime glass (or glass used in the construction industry), highlighting both the work of Griffith and Beason. Even though ASTM E1300 is one of the most comprehensive formulations for predicting glass failures, it has many limitations. This presentation will show some of the raw laboratory data used to determine the resistance properties of annealed. heat-strengthened, and fully tempered glass. Also, the presentation will cover such parameters as the coefficient of variation, residual compressive surface stress, and various interpretations on a factor of safety that can affect the determination of mean failure stress for glass. The presentation will show how a new ASTM working group has developed an updated definition of glass failure that may be used in conjunction with Load Resistance Factor Design methodology as presented within ASCE7.
At the end of this presentation, we will review a project case study. The study will show an example of investigating a glass panel’s damage. We will show an overview of the computations used to fix the damaged glass to allow the reuse of the glass panel.
Alex Katz, P.E., Restoration Engineer
Alex Katz is a Restoration Engineer for Walker Consultants’ Chicago office. He joined Walker in 2016 with a master’s degree in Civil Engineering from the University of Texas at Austin where he performed research in prestressed concrete bridge girders. During his five years at Walker, he has employed experience in structural evaluations, non-destructive testing, structural load testing, structural analysis, and maintenance and strengthening repair design on a wide variety of projects with unique challenges.
Large Scale Parking Structure Vehicle Fire Damage Evaluation and Restoration
In September 2018, a seven-alarm fire, involving sixty-plus vehicles, caused severe structural damage to the eastern portion of a 5-level precast concrete parking structure serving a large shopping mall in Brooklyn, New York. Walker was engaged to perform an investigation to evaluate the sustained structural damage caused by the fire, prepare a report of our findings, and develop repair documents and prepare construction administration services to restore the structure to its pre-fire operating conditions by Black Friday 2019.
Alex Katz led the three-day field assessment in October 2018 which involved documentation of visual observations, non-destructive evaluation of structural elements, sampling of concrete materials for petrographic analysis, structural analysis to determine the remaining capacity of damaged elements, and in-situ load testing of two fire-damaged inverted-tee girders. Cyclic load testing of the two heavily damaged girders in accordance with the provisions of ACI 437.2-13 proved adequate remaining capacity in the damaged member over 4-hours of testing overnight, resulting in a savings of half the repair cost.
Identified repairs include concrete repairs to fire-damaged single-tee beam flanges and stems, columns, girders, and topping slabs, as well as repairs to waterproofing, lighting, and plumbing systems. Tee beam strengthening repairs were designed with either mild-reinforced stem encasements or externally bonded carbon-fiber-reinforced polymer (CFRP). Large areas of tee-beam flanges needed to be replaced full-depth in a phased manner. The full-depth flange repairs required a counterweighting scheme to resist the remaining prestressing force after the removal of the flanges. The results of the investigation and repair types and quantities included in Walker’s Construction Documents withstood the scrutiny of a structural peer review from the insurance company’s representatives without reduction in scope. The assessment and repairs were conducted while undamaged portions of the structure remained in operation. As a result of excellent planning, coordination, and cooperation among the entire project team, the restoration was completed in time for the structure to be fully operational by Black Friday 2019.
The proposed presentation will cover mechanisms by which fire exposure damages concrete structures, the range in severity of damage and replacement costs that can be expected from vehicle fire events, methods of fire damage evaluation of concrete structures, as well as the project-specific evaluation, repair design, and construction challenges overcome by the project team over the course of this large-scale fire damage restoration project.
Allison Toonen-Talamo, Associate III
Klein and Hoffman, Inc.
Allison is an Associate at Klein and Hoffman and serves under the architectural and building enclosures team. Within the firm, she utilizes investigative procedures, historical review and research, technical development, condition assessments, and construction administration services, for various Chicago structures including historic Landmarks, residential, commercial, and municipal buildings. Allison serves and holds leadership positions with various organizations locally, statewide, and nationally. She recently received the 2020 American Aspire Award present by the National Trust and has been listed as one of 2021 Landmarks Illinois 50Forward Influencers.
Preserving the Beauty of Cast Iron During a Forensic Analysis
Cast iron as a building enclosure material can pose some challenges if the team does not have an appropriate approach towards repairs, and if the building is listed as a landmark, this could be even trickier. Cast iron is an alloy with high carbon content and compared to its sister metals, wrought iron, and steel, cast iron is considered to be more durable, corrosion-resistant, and easier to create designs with the use of a mold. Between the late 19th to early 20th centuries, cast iron for building facades was a common building material in the U.S due to the cost, workability of the material, and availability. Highly decorative molds can be used for the molten cast iron, which one local architect, Louis Sullivan, mastered in his art of highly detailed cast-iron storefronts.
However, like most materials for the building façade, if not kept watertight or maintained, failure of the façade can occur. Due to the brittleness of cast iron, despite the strength it offers compared to its sister metals, not all repair recommendations may be suitable, and all repair methods should be evaluated based on an understanding of what conditions the cast iron will experience in a long-term setting.
The project our firm is currently working on in the Chicago Loop has included ongoing efforts with the entire project team to develop an appropriate long-term cast iron repair scope that meets Chicago Landmark requirements while also being cost-effective. Due to limitations at the beginning of this project, the initial steps to review the existing condition of the cast iron were not able to be performed which left a few unknowns regarding the cast iron material and existing cast iron anchorage systems used on the building. As the work for the coating and sealant repairs was being performed, the need for additional cast iron repairs was discovered resulting in necessary revisions to the repair documents, potential delays to the project, and unplanned design and repair costs.
The best approach to understanding the exposure conditions of the building and how it is performing is to perform a condition assessment of the facades to note items like failed coatings, sealants, fasteners, and damaged cast iron. During the condition assessment phase, it is recommended to perform testing on the cast iron and coating(s), if any coatings exist, to the potential presence of hazardous materials and to understand the cast iron composition, potential contamination within the metal, and the metal properties, such as its compressive and/or flexural strength. Typically, it would be recommended to perform a series of invasive inspection openings to document the underlying as-built conditions and identify cladding attachment types and building structural systems, particularly if the original building design drawings are unavailable or incomplete. Once the condition assessment, documentation of existing conditions, and testing have been completed, then the project team will be better able to determine an appropriate repair scope and estimated cost associated with the repairs.
Stephen Pessiki, Ph.D., FACI, FPCI, Senior Vice President
Thornton Tomasetti, Inc.
Stephen Pessiki is a Professor of Structural Engineering at Lehigh University and a Senior Vice President in the Forensic Engineering Practice at Thornton Tomasetti Inc. His research and teaching interests include the behavior and design of concrete structures, nondestructive evaluation of materials and structures, and fire effects on structures. Dr. Pessiki joined the Lehigh faculty in 1990, and he served as Chair of the Department of Civil and Environmental Engineering at Lehigh from 2005-2011. He has served on numerous national and international technical committees, including as Chair of ACI Committee 228 Nondestructive Testing of Concrete. He has been recognized for his teaching and research, and he is a Fellow of the American Concrete Institute and the Precast/Prestressed Concrete Institute. A dedicated teacher, Dr. Pessiki has taught thousands of students in his 30-year teaching career.
Joseluis Alvarez, Senior Engineer
Thornton Tomasetti, Inc.
Joseluis Alvarez is currently a Senior Engineer at Thornton Tomasetti, Inc., where he has been working since 2018. Joseluis graduated from the University of Illinois at Chicago in December 2017. He plays an active role across multidisciplinary projects involving: structural design, renewal, forensics, and property loss consulting.
Case Study in Service Life Prediction of a Post-Tensioned Concrete Parking Structure
Questions about the performance and durability of newly constructed concrete structures are uncommon unless serious concerns arise during construction. Following a recent pour at a post-tensioned concrete mid-western U.S. parking structure, widespread topside cracking and underside consolidation voids, which had led to exposed tendons, raised several red flags to all parties involved. The facility owner requested Thornton Tomasetti to investigate these conditions and their impact on service life and to provide recommendations for repair or replacement of the concrete. The presentation describes the investigation of the structure, including the inspection, nondestructive testing, concrete material characterization, service life modeling, and analysis that was performed. The focus of the presentation is the prediction of the service life of the structure based on the assessment of key parameters including concrete cover, concrete resistance to chloride ingress, and exposure conditions, and conclusions that impacted the decision regarding repair versus replacement.
Leonard J. Morse-Fortier, Ph.D., P.E., Staff Consultant
Simpson Gumpertz & Heger Inc.
Dr. Leonard J. Morse-Fortier is a Staff Consultant with Simpson Gumpertz & Heger Inc. (SGH). A self-described recovering academic, he joined SGH in 1996 after a decade in academe. He has worked in wind engineering, structural design, structural investigation, and design for repair and rehabilitation, including historic preservation. Currently, he specializes in forensic engineering, remains active in ASCE's Forensic Engineering Division, and was honored with the ASCE Forensic Engineering award for 2017.
Understanding Wood Moisture Movement in Diagnosing Problems with Wood-Frame Structures
Wood responds to changes in atmospheric conditions, swelling as it absorbs moisture under elevated humidity, and shrinking when surrounded by dry air. The affected wood, whether it is used for framing or applied as a finish, will move as it expands and contracts. Where the movement is constrained, or where the movement changes the members’ geometry, the result may be damage. As the symptoms of hygroscopic movement may resemble damage from external forces, understanding wood shrinkage can aid in correctly diagnosing the underlying causes of building damage. This paper provides two examples of damage that results from wood shrinkage.
Alan Humphreys, Metallurgist
Simpson Gumpertz and Heger
Alan has 25 year career as a Metallurgist, specializing in Corrosion Engineering, Fracture and Fatigue, and Failure Analysis.
Forensic Analysis of Failures in Plumbing Pipe
When properly designed and installed, plumbing systems will provide many decades of problem-free service. However, actions during the construction or renovation of a building can have unintended consequences that can dramatically reduce the service life of plumbing systems. This article details forensic analysis of some recent plumbing pipe failures caused by construction problems and discusses methods to avoid such problems.
Wiss, Janney, Elstner Associates
Dr. Thomas Frankie is a licensed structural engineering who specializes in the assessment of structures compromised due to failure, accident, natural disaster, or material degradation. Since joining WJE in 2013, Dr. Frankie has investigated concrete-related problems in numerous structures including historic and modern buildings, bridges, stadiums, industrial facilities, parking garages, cooling towers, seawalls, pavements, and foundations. He has applied advanced ﬁeld and laboratory investigation techniques to hundreds of unique projects.
On August 9, 2019, Tyson Foods' Holcomb, Kansas beef plant experienced the ﬁrst large ﬁre in the meat processing industry in nearly 20 years. The long-burning ﬁre precipitated the collapse of a portion of the high roof over the mechanical mezzanine, which housed equipment for numerous critical plant processes. This took portions of the plant, the second largest in the United States, out of operation for months. The pressures of substantial business interruption costs, as well as the market consequences for cattle feeders from the Southern Plains region, necessitated a rapid response. This presentation highlights the investigation into the extent of damage to precast members, including visual inspection, non-destructive and laboratory evaluations, testing, simulation, and analyses. Based on this investigation, members recommended for repairs or removal and replacement were identiﬁed. Consulting and construction observations related to the removal
of collapse debris and proposed repair approaches will also be discussed.
Mr. Schmitt has been with WJE since he graduated from the University of Illinois at Urbana-Champaign in 2007. Before joining WJE’s Chicago Office in 2016, he worked in WJE’s Janney Technical Center (JTC) and Structural Laboratory in Northbrook, Illinois. He has over 14 years of experience in the investigation, evaluation, and repair of a variety of concrete structures, including buildings, parking garages, industrial facilities, dams, and silos. His work has taken him across the US and to India. His investigations have involved materials sampling, field and laboratory testing, and non-destructive evaluation. He currently serves on technical committees for SEAOI and ICRI Chicago to develop and coordinate local educational programs.
WJE conducted an extensive review of assessment reports prepared by other consultants and of the original structural drawings and calculations. The project team also performed a limited condition assessment of the silos at the grain terminal with the collapsed hopper and independent structural analysis. WJE’s analysis was performed using the load and resistance factor design method in accordance with ACI 318-08 and ACI 313-97. WJE concluded that the hopper anchorage was severely under-designed for gravity and seismic load cases due to poor design assumptions and errors.
WJE also evaluated the hopper anchorage using unfactored load demands and code-calculated unfactored strengths. Our analysis demonstrated that the magnitude of the structural deficiencies was enough to cause a concrete breakout in tension of the hopper anchorage under normal operating conditions. WJE recommended retrofitting all the hopper anchorage to address the structural deficiencies as the existing concrete distress was likely to worsen with continued use and could have led to hopper collapse under normal use or under earthquake-loading conditions.