Rockingham, Vermont Designing for Resilience and Durability on the Longest Spliced Precast Concrete Girder Bridge in Vermont
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SUMMER 2021
Designing for Resilience and
Durability on the Longest
Spliced Precast Concrete Girder
Bridge in Vermont
Rockingham, Vermont
BOH BROS. CONSTRUCTION CO.’S LONGEVITY
SERVES THE GULF COAST
CONDITION EVALUATION OF THE JFK CAUSEWAY
POST-TENSIONED SEGMENTAL BRIDGE
North Padre Island, Texas
MIDDLEBURY BRIDGE AND RAIL PROJECT
Middlebury, Vermont
CONTENTS
20
Features
Contractor’s Longevity Serves the Gulf Coast 6
For more than 100 years, family-owned Boh Bros. Construction
Co. has shaped the region surrounding its New Orleans home
base through heavy civil and concrete bridge work that connects
the region
Condition Evaluation of the JFK Causeway
Post-tensioned Segmental Bridge 20
Middlebury Bridge and Rail Project 24
Designing for Resilience and Durability on the
Longest Spliced Precast Concrete Girder
Photo: Texas Department of Transportation. Bridge in Vermont 28
Departments
24 Editorial 2
Concrete Calendar 4
Perspective—Diversity, Equity, and Inclusion 10
Perspective—Perspectives on Structural
Behavior and Redundancy:
Load Path Redundancy 12
Perspective—The Digital Twin Evolution 16
Aesthetics Commentary 31
Creative Concrete Construction—
Threading a Needle 32
Concrete Bridge Preservation—Preserving
Photo: VHB. Our Infrastructure by Using Modified Silica Gel 35
Concrete Bridge Technology—
Detailing Segmental Concrete
28 Box Girders for Constructability 38
Professor’s Perspective—The Role of
Analytical Tools in Innovation 40
Safety and Serviceability—Designing
Photo: Flatiron Construction Co.
for Construction Loads on Concrete Bridges 43
FHWA—Eliminating Bridge Joints
with Link Slabs 46
Concrete Connections 48
LRFD— Crack-Control Reinforcement:
Strength and Serviceability Implications 49
Perspective—Ethics and Culture:
You Can’t Ride a Bike Without Wheels 51
Photo: HDR.
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ASPIRE Summer 2021 | 1
EDITORIAL
Our Fundamental Principles:
Editor-in-Chief
William N. Nickas • wnickas@pci.org
Managing Technical Editor
Photo: PCI.
Ethics and Quality Dr. Reid W. Castrodale
Technical Editors
Dr. Krista M. Brown, Angela Tremblay
William N. Nickas, Editor-in-Chief
Associate Editor
Thomas L. Klemens • tklemens@pci.org
T he American Association of State Highway and
Transportation Officials (AASHTO) has released
a video profile of Victoria Sheehan, the 2020–2021
records. Over the years, I’ve worked with colleagues who
work to maintain transparency in every aspect of our
projects, starting with our plans and records. Preserving
Copy Editors
Elizabeth Nishiura, Laura Vidale
AASHTO president.1 She has been commissioner of these critical documents for years after projects are Layout Design
the New Hampshire Department of Transportation delivered is key. Without good record-keeping, we Walter Furie
(DOT) since 2015. Sheehan has a master’s degree in cannot trace the designs and calculations used in
structural engineering and architecture, and started projects or understand how past decisions affect the Editorial Advisory Board
her career in the accelerated bridge construction future of our transportation infrastructure. William N. Nickas, Precast/Prestressed
Concrete Institute
program at the Massachusetts DOT. It’s pretty neat How do we ensure that the programs we have in
Dr. Reid W. Castrodale, Castrodale
to see a structures professional in the top agency place live up to the demands of our profession? I Engineering Consultants PC
leadership role. Please take a moment to watch the Gregg Freeby, American Segmental Bridge
video and listen to Sheehan’s thoughts on diversity, Institute
technology, and other changes that will impact Pete Fosnough, Epoxy Interest Group of the
core functions of the transportation industry. She Concrete Reinforcing Steel Institute
emphasizes the need to expand the skill sets of our Alpa Swinger, Portland Cement Association
workforce and to fund a stable program with a long- Tony Johnson, Post-Tensioning Institute
term horizon, showing leadership the benefits of
Cover
“predictability for longer-term planning.” The design-build team evaluated several
Watching the AASHTO video got me to thinking alternative structure types for the new twin
again about the fundamental principles of delivering bridges on Interstate 91 near Rockingham, Vt.,
well-designed, high-quality products and assets to our ultimately selecting precast concrete spliced-
customers/owners. In the Spring 2021 issue of ASPIRE®, girder bridges that will exceed the 100-year
Dr. Richard Miller authored a Professor’s Perspective service life requirement. Photo: HDR.
on ethics and judgment and how, as a university
professor, he approaches the topic with his engineering https://doi.org/10.15554/asp15.3
students.2 In this issue on page 51, Dr. Anna Pridmore suggest that we start with the “AISC/PCI White Paper Ad Sales
continues the discussion with a Perspective on the on Quality Systems in the Construction Industry”4 as Jim Oestmann
new American Society of Civil Engineers (ASCE) a primer. This collaborative report is an easy read, Phone: (847) 924-5497
Code of Ethics3 and what it takes to foster an ethical provides a bit of background on the roles of technical Fax: (847) 389-6781 • joestmann@arlpub.com
culture and impact behavior. She reminds us of the institutes and certification programs, and outlines the
importance of fostering a culture of empowerment 12 elements of comprehensive quality systems for a Reprints
lisa scacco • lscacco@pci.org
and communication that will impact behavior within technical institute’s plant certification program.
companies and organizations. In her words, “Engineers A variety of models are available to help us Publisher
can drive culture shifts that empower us and others to establish quality programs and systems in our Precast/Prestressed Concrete Institute
talk about potential and ongoing problems.” organizations. At their core, quality programs Bob Risser, President
Organizations can strengthen and support our demand attention to detail, standardized procedures/ Postmaster: Send address changes to ASPIRE, 8770 W. Bryn Mawr
Ave., Suite 1150, Chicago, IL 60631. Standard postage paid at Chicago,
individual professional ethics by sustaining a culture work instructions, and an assurance that provided IL, and additional mailing offices.
of quality. A quality company culture starts with guidance is followed. This outlined approach provides ASPIRE (Vol. 15, No. 3), ISSN 1935-2093 is published quarterly by the
Precast/Prestressed Concrete Institute.
leadership that sets and upholds solid policies, with the guidance for establishing the organizational Copyright 2021 Precast/Prestressed Concrete Institute.
clearly stated quality objectives and standard operating stewardship (body of knowledge) to enhance If you have comments on an article or a suggestion for a project or
topic to be considered for ASPIRE, please send an email to info@
practices. A fundamental tenet is that all quality systems established quality programs or aid in building a new aspirebridge.org
begin and end with complete and comprehensive program starting from ground zero.
American Segmental Bridge Institute Epoxy Interest Group Expanded Shale Clay and Slate Institute
Portland Cement Association Post-Tensioning Institute
2 | ASPIRE Summer 2021
In Dr. Miller’s article on teaching ethics, he procedures, programs, and systems can save the day.
PCI Ultra-High-
explains how he uses the example of an expressway Organizations and companies must cultivate a dual
dividing a neighborhood to frame the discussion mindset of both rigorous adherence to standards and Performance Concrete
with his students of the societal, environmental, quality control/assurance procedures as well as being Workshop set for September
and economic ramifications of their work (both open to the spontaneous communication of ideas
locally and globally). His students must navigate and concerns. If your organization is contemplating PCI is hosting an Ultra-High-Performance
this engineering dilemma and consider the effects joining forces with an entity that doesn’t take open Concrete Workshop Tuesday, September 21,
and influence this solution could have on adjacent communication, ethics, quality management, quality 2021. This one-day workshop will gather
established communities. They must take into assurance, and quality control seriously, consider experts from across the precast concrete
account the human aspects of their designs. This another collaborator. industry to discuss various research
example led me to wonder: Is it at this juncture where and development initiatives for the
engineering decisions shift from science to art? References implementation of ultra-high-performance
Now let’s talk through indirect impacts: what 1. American Association of State Highway and
concrete (UHPC) in precast concrete
happens when a seemingly minor misstep becomes Transportation Officials. 2021. “AASHTO President
a global issue? On March 23, 2021, the Ever Given, Victoria Sheehan Profiled in New Video.”
components.
one of the largest cargo ships in the world, ran www.youtube.com/watch?v=L_c8RzuoEp8. The workshop will cover design
aground, essentially shutting down global shipping 2. Miller, R. 2021. “Ethics and Judgment Are About considerations for architectural and
through the Suez Canal until the ship was freed More Than Just Safety.” ASPIRE 15(2): 50–51. structural precast UHPC components, such as
on March 29. The inability to move cargo through 3. American Society of Civil Engineers (ASCE). 2020. UHPC material selection for nonproprietary
the canal had the potential to cause significant “ASCE Code of Ethics.” https://www.asce.org/code mixture designs, characterization and
and costly delays for construction industry-based -of-ethics. quality control testing of UHPC, and
projects globally. Perhaps it delayed the delivery of 4. American Institute of Steel Construction (AISC) production and fabrication of precast UHPC
construction material and heavy equipment to your and Precast/Prestressed Concrete Institute (PCI). components.
projects. “AISC/PCI White Paper on Quality Systems in The workshop will be at Loews O’Hare in
If your project is affected, will that cause an the Construction Industry.” Accessed May 6, 2021.
Rosemont, Ill. For more information, go to
out-of-sequence issue? Are you and your team https://www.pci.org/PCI_Docs/Certification/
prepared to adjust? During times of uncertainty, our AISC_PCI_Quality_Systems_White_Paper.pdf.
https://www.pci.org/events
ethics may be tested, and our reliance on quality
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ASPIRE Summer 2021 | 3
CONCRETE CALENDAR FOR SUMMER 2021
The events, dates, and locations listed were accurate at the time of publication
CONTRIBUTING AUTHORS but may change as local guidelines for gatherings continue to evolve.
Please check the website of the sponsoring organization.
Raj Ailaney is a senior
bridge preservation July 11–15, 2021 November 15–20, 2021
engineer in the Federal AASHTO Committee on Bridges PTI Certification Training:
Highway Administration and Structures Annual Meeting All Levels
(FHWA) Office of Bridges Online Austin, Tex.
and Structures, where he
develops guidance and July 26–August 4, 2021 December 8–10, 2021
policies for preservation of AASHTO Committee on Materials Accelerated Bridge
bridges in support of FHWA’s performance-based and Pavements Annual Meeting Construction Conference
program to maintain bridges in a state of good Online Online
repair. He also chairs the FHWA’s Bridge
Preservation Expert Task Group. August 10, 2021 January 9–13, 2022
2022 PCI Design Awards Transportation Research
Dr. Oguzhan Bayrak is a Submission deadline Board Annual Meeting
professor at the University Walter E. Washington
of Texas at Austin and was September 13–16, 2021 Convention Center
inducted into the 2021 Western Bridge Washington, D.C.
university’s Academy of Engineers Seminar
Distinguished Teachers in Online January 19–21, 2022
2014.
World of Concrete
September 13–18, 2021 Las Vegas Convention Center
PTI Certification Training: All Levels Las Vegas, Nev.
Drew G. Burns is the
Phoenix, Ariz.
executive director for the
March 1–5, 2022
Slag Cement Association
September 20, 2021 PCI Convention with
and Great Lakes Cement
ASBI Grouting Certification The Precast Show
Promotion Council in
Training Kansas City Convention Center
Detroit, Mich.
Online Kansas City, Mo.
September 22–25, 2021 March 27–31, 2022
Frederick Gottemoeller is PCI Committee Days and ACI Spring 2022 Conference
an engineer and architect Technical Conference Caribe Royale Orlando
who specializes in the Loews Chicago O’Hare Hotel Orlando, Fla.
aesthetic aspects of bridges Rosemont, Ill.
and highways. He is the
author of Bridgescape. September 26–30, 2021
AREMA 2021 Annual Conference
with Railway Interchange
Online
A HELPFUL HINT
Dr. Anna Pridmore is the
vice president of Municipal October 5–8, 2021 For a complete list of search results in
and Nuclear Infrastructure PTI Committee Days the online version of ASPIRE® users must
for Structural Technolo- Hyatt Regency search from within an issue.
gies. She volunteers in Coconut Point
Once an issue is open, click the search
leadership for the Bonita Springs, Fla.
button and type the search term. Then
American Society of Civil click the folder button to search all
Engineers and serves on October 17–29, 2021
archived issues.
committees for several other industry organiza- ACI Fall 2021 Convention
tions to develop and improve the profession. Hilton Atlanta Downtown This will return all results of the search
Atlanta, Ga. from all past issues of ASPIRE.
Dr. John Stanton is the
Nielsen Professor of Civil November 8–10, 2021
Engineering at the ASBI 2021 Annual Convention and
University of Washington Committee Meetings
in Seattle where he has Westin La Paloma Resort and Spa
taught and conducted Tucson, Ariz.
research,, much of which
concerns prestressed
concrete bridges, for more than 40 years.
4 | ASPIRE Summer 2021
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FOCUS
Contractor’s Longevity
Serves the Gulf Coast
For more than 100 years, family-owned Boh Bros. Construction Co. has shaped the region surrounding
its New Orleans home base through heavy civil and concrete bridge work that connects the region
by Monica Schultes
Boh Bros. Construction Co. has a 160-acre facility that includes 4200 ft of waterfront along the Gulf Intracoastal Waterway. On the
Lake Pontchartrain Causeway project, this waterway access gave the company an advantage while constructing complete safety
shoulder segments. The components were cast and assembled at the facility, and then loaded onto self-propelled modular transporters
(SPMTs), which were rolled directly onto barges. The assemblies were erected from the barges using SPMTs and without impacting
travelers on the causeway. All Photos: Boh Bros. Construction Co. LLC.
T h e l o n g h i s t o r y o f B o h B ro s . Plauche says, “We try to maintain “steady as she goes” philosophy. “We are
Construction Co. is rare in the our reputation of honorably conservative in our thinking and believe in
construction industry and is a testament s erv i n g our c ommuni ti es .” That doing the right thing. Our reputation for
to their commitment to New Orleans devotion to the local community a high degree of integrity is paramount.”
and southeaster n Louisiana. The was validated as Boh Bros. worked
company’s longevity is also a reflection to help restore New Orleans to its That attitude has been perpetuated over
of its management, according to former glory. The rapid response also the years across a workforce whose
Jeff Plauche, senior vice president of foreshadowed their penchant for members often stay with the company
preconstruction and development. This alternative project delivery methods. for their entire careers. “Funding
family-owned company has lasted from sources may change and the industries
generation to generation thanks to a
philosophy of service to the community,
“We try to we perform in may vary, but the way
we do business never changes,” says
customers, and coworkers. maintain our reputation Plauche.
In the wake of Hurricane Katrina in
of honorably serving our Although there is tremendous turnover
2005, it was all hands on deck, 24 communities.” in the construction industry, that is not
hours a day, to restore the Interstate the case here. Boh Bros. has always
10 ( I- 10) t win s p a n s o v e r L a k e Family Values been privately held and some years ago
Pontchartrain that had been broken Boh Bros. considers their employees started an employee stock ownership
into pieces by the storm surge. Boh part of the family. “That is what makes plan to recognize the people who
Bros. employees worked on emergency us unique,” says Plauche. More than a are critically important to the success
repairs to the bridge, despite their own century ago, the Boh family started of the company and to reward their
personal losses. a company based on integrity and a loyalty.
6 | ASPIRE Summer 2021
of the two contracts for construction
of the elevated I-10 twin spans that are
in use today (for details, see the article
in the Spring 2011 issue of ASPIRE®).
Recently, they were awarded another
major project: Working for the Greater
New Orleans Expressway Commission,
they completed a $55 million upgrade
to construct new safety shoulder
segments along the Lake Pontchartrain
Causeway, the longest bridge in the
United States.
CMAR Solutions
Boh Bros. served as the construction
manager at risk (CMAR) for the Lake
Aerial view of the marine deck span installation of the Lake Pontchartrain Causeway,
Pontchartrain Causeway project,
showing tugboats holding the barges in place while the self-propelled modular
which included constructing twelve
transporters complete the installation. The new designated breakdown areas address
1008-ft-long safety shoulders, or
both traffic and safety concerns and were a much-needed addition to the structure.
“safety bays,” along the existing bridge
When the bridge was first completed in 1956, the annual traffic count was 200,000; now
alignment.
the bridge carries 12 million vehicles per year.
Gulf Coast The interstate highway program drove The CMAR approach expedited the
With strong ties to the gulf region and much of that expansion, as did the design and planning stages and
their auspicious beginnings in New development of the power industry. allowed the project team to resolve
Orleans, Boh Bros. has performed “As the entire industrialized world key challenges and minimize project
thousands of projects in the area and evolved, we did too,” explains Plauche. risk. Throughout the process, Boh
continues to seek out opportunities The area south of Baton Rouge, La., Bros. collaborated on constructability,
close to home. Staying local benefits is considered a coastal environment schedule, and budget to help guide the
employees, who can return to their and is conducive to concrete bridge design. In less than nine months, the
families after work. Building in the construction. As concrete girder project moved from preconstruction to
region also reinforces the company’s technology has developed and longer construction, a process that typically
areas of expertise. They have extensive spans have become more common, takes much longer.
knowledge about the intricacies of concrete can be considered in more
working along the Gulf Coast. South long-span project solutions. Traffic was a primary consideration. To
Louisiana soils are very tricky, and minimize traffic disruptions, the team
working along multiple waterways The evolution of Boh Bros.’ expertise opted for precast concrete piles, pile
presents challenges of variable water came with experience in the many and caps, and deck span modules that were
depths and weather conditions that can varied concrete structures that cross the manufactured off site. The monolithic
affect construction. Louisiana waterways. In all, Boh Bros. deck span modules, or safety bay sections,
has completed three projects on I-10 are composed of a concrete deck and
Boh Bros. has invested in their own over Lake Pontchartrain. After their traffic barrier cast onto AASHTO girders
equipment and typically self-performs stellar performance in 2005 on the at the Boh Bros. facility. With this strategy,
85% to 95% of their work. They have emergency repairs, they completed one lane closures were minimized, simplifying
the option of using their own casting
yard or partnering with local precasters The Lake Pontchartrain Causeway piles and precast concrete pier caps awaiting
for bridge components. In addition installation of the precast concrete shoulder assemblies. The safety shoulder segments
to Boh Bros.’ own precast concrete were supported by one hundred ninety-two 54-in.-diameter precast concrete piles
fabrication shop, the New Orleans ranging from 54 to 112 ft in length.
operations yard also contains a safety
training facility, carpentry shop, piling
and marine facilities, and equipment
and material storage, and has direct
barge access.
Now a major player in bridge
construction in the region, Boh Bros.’
expertise expanded from municipal
and road work to pile driving and
bridge work. Their portfolio evolved
as their in-house experience grew.
ASPIRE Summer 0 |7
Su e 2021
In 2005, Hurricane Katrina tore apart sections of the Interstate 10 twin spans over Lake Pontchartrain. After resurrecting five miles
of downed causeway pieces and making emergency repairs in less than 29 days to get one of the bridges reopened, Boh Bros. was
awarded the contract for the new, more resilient trestle portion of the Interstate 10 twin bridges.
construction sequencing and greatly The safety shoulder modules were creative project solution was recognized
reducing inconvenience to the public. constructed in an assembly-line process by awards from the Associated General
The completed safety bays provide a safe at Boh Bros.’ waterfront construction Contractors of America and PCI (PCI
haven for stranded motorists to pull off facility, increasing safety and quality. 2021 Best Rehabilitated Bridge Award).
the causeway. All deck span modules were assembled
off site, with precast concrete girders “The causeway project is one of the
Boh Bros. was a critical part of the delivered to the yard and a composite best stories we can tell in the CMAR
preconstruction process and their deck applied, before the completed units environment,” says Plauche. “We
engineering background enabled the were barged to the bridge. listened to the commission staff, the
team to provide sound constructability designer, Volkert, and the owner’s
input. Plauche says, “We have a built-in The CMAR team mentality was critical representative, Huval & Associates, and
appreciation for how changes impact to the decision to do as much work truly acted as one team. We met their
design. That better enables us to suggest as possible from the water instead of expectations and exceeded their goals.
construction solutions that work for both from the bridge deck. Risk mitigation I know it sounds cliché, but that is the
the contractor and designer, maximizing for the traveling public, cost risk, and definition of building a project with the
benefits to the owner.” safety risk were all addressed before least disruption to all stakeholders.”
construction started.
“We have a built- Company of Builders
in appreciation for how Waterside Construction Plauche sees the CMAR project
The most impactful decision for the delivery method as the next step in the
changes impact design. causeway project was to incorporate company’s evolution. “In the future, we
That better enables us accelerated bridge construction (ABC)
techniques and fabricate the bridge
see Boh Bros. doing what we do best,
employing more innovative methods.
to suggest construction deck span modules off site, then We are a company of builders. Many
solutions that work for transport them by barge to the bridge
from the Boh Bros. facility. The ABC
field supervisors have come up through
the craft ranks, growing our technical
both the contractor and approach enabled pile driving and and construction expertise.”
designer, maximizing precast concrete pile cap construction
to be performed concurrently and Project delivery methods have been
benefits to the owner.” facilitated construction exclusively using slow to change in Louisiana. The
marine equipment. With the piles and traditional design-bid-build approach is
The team procured advance work caps in place, the crew barged the a good fit for typical everyday projects,
packages, expediting items that completed deck units to the site. but for those projects with high levels
were approved for fabrication before of complexity, multiple stakeholders, or
100% design completion. Before the “In order to have as little impact on potential funding issues, it makes sense
construction contract was executed, a the traveling public as possible, we to move toward design-build, CMAR, or
test pile program was initiated, as was came up with the modular scheme to construction manager/general contractor
the production of precast, pretensioned install sections coming up from the project delivery methods.
concrete girders and concrete cylinder waterside,” explains Plauche. “Using
piles. Boh Bros. was ultimately awarded self-propelled modular transporters on “We have always helped our clients
the construction contract, and the barges allowed us to set the completed as a team member working for the
company guaranteed the maximum deck sections with many motorists good of the project, not adversarial
price and schedule duration. unaware we were ever there.” The or self-serving,” says Plauche. “These
8 | ASPIRE Summer 2021collaborative procurement methods are
a natural fit for us and have allowed us
“Instead of Boh Bros. Construction Co.
to win more projects in the region since the old roll of plans,
Boh Bros. Construction Co. is a family-
their adoption.”
everyone has up-to-date owned, third-generation construction
As a contractor that performs much of information, just-in- company based in New Orleans,
their own work, Boh Bros. can apply La. Their work includes heavy civil
years of experience and lessons learned
time, all the time.” construction, piling, marine, utilities,
to enhance the owner’s experience. paving, and site work. Since 1909, the
“This is how projects should be done.
In-House Expertise company has had a lasting impact on
With an in-house engineering and
We want to be a builder and integral the bridges and byways that connect
constructability group comes the
project team member, not considered the Gulf Coast. They demonstrate that
just another bidder,” explains Plauche. means to quickly solve shoring, rigging, building infrastructure not only supports
and other issues that can arise on commerce and commuters but also is
Jobsite Technology site. While many of their competitors the backbone of the community.
With fewer skilled workers to fill the outsource this service, Boh Bros. has
long maintained their own engineering The family name is ubiquitous with
demand, construction companies have
staff. “Our engineering team knows construction in the New Orleans
to do more with less time, less money,
our strengths and capabilities, and the metropolitan area. Through the decades,
and fewer people. Boh Bros. has
preferences of our field personnel. They Boh Bros. has weathered the good
adopted innovative methods to mitigate
can communicate quickly and work to times and the bad, transforming the
the shortage of skilled laborers in the
provide custom solutions. I don’t know state’s bridge system, constructing the
overall workforce and on their jobsites.
anyone else in the area who does it that Ernest N. Morial Convention Center, and
In the past, they were able to overcome
way,” says Plauche. completing numerous post-Hurricane
challenges with huge groups of skilled
Katrina repairs, including rebuilding the
craftsmen. But with the current and future
limits of skilled labor, they have turned Safety First Interstate 10 twin spans. Through their
Inside knowledge of preferred methods commitment to quality work and public
to technology and finite level planning.
also helps Boh Bros. with their safety involvement, the company has earned
“While our workforce has decreased in
record and minimizes their need the respect of its peers, clients, and
number, they have increased in technical
to develop new techniques for every community.
ability,” explains Plauche.
project. “Everything we do starts with
“We have embraced technology, a focus on safety. By planning for safety says Plauche. “Despite another layer
especially how we communicate among first, the quality results, productivity, and of safety planning, we were quick
ourselves and with our customers. We efficiency follow,” says Plauche. to adapt and keep workers safe and
are always looking for new ways to make healthy. The challenges posed by the
it easier for people in the field.” Using “We prioritize the safety of the pandemic helped combat complacency
technology for field collaboration, Boh traveling public and our own people’s and reinforced existing strategies.”
Bros. makes use of drones, rugged tablet safety, and everything flows from
computers, and ProCore construction that,” he adds. Statistically, 2020 was Boh Bros. has worked for the past
management software. “Instead of the the safest year in the company’s long century to complete projects while
old roll of plans, everyone has up-to- history. Civil construction was deemed staying dedicated to the team
date information, just-in-time, all the an essential industry, and Boh Bros. environment. Plauche says, “While we
time,” emphasizes Plauche. Being able to continued work unabated despite can share a thousand pictures of bridges
share daily logs, photos, comments, and COVID-19 restrictions. throughout our rich history, we want to
requests for information, and providing emphasize our future moving forward
clients access to that information, makes “During the pandemic, we were able with innovative project delivery methods
all the difference. to keep all of our people working,” and technology.”
At 30 ft high, the deck
for the new Interstate
10 twin-span bridge is 21 ft
higher than the original bridge.
Lower-level connections between the
super- and substructures are designed to
resist uplift forces caused by waves. The new
bridge was built with high-performance, high-
strength concrete that is more resistant to saltwater
corrosion than conventional concrete, and which is
expected to provide a 100-year service life (for more details,
see the article in the Spring 2011 issue of ASPIRE®.)PERSPECTIVE
Diversity, Equity, and Inclusion
How recent social justice movements can have
a positive effect on the construction industry
by Drew G. Burns, Slag Cement Association
Recent events in the United States industry breakdowns show that more term is meant to acknowledge that
have prompted various social justice than 30% of Hispanic/Latino workers not all people of color face the same
movements to address racial disparities were employed in jobs associated with levels of injustice.
within our nation’s systems and production, transportation, materials,
institutions. These movements, regardless natural resources, construction, and A helpful analogy used many times is
of personal opinions, are ushering in a maintenance. In contrast, just 21.9% that diversity is like being invited to the
demand for more transparency from of Black workers were employed in party; inclusion is like being asked to
those in power. The American Society of these fields, a statistic that highlights an dance. Inclusion focuses more on who is
Association Executives’ ASAE Handbook opportunity to expand hiring efforts in respected, expected, and integrated into
of Professional Practices1 includes a list this community. a group, as opposed to just being there.
of management trends to watch, which To maximize output, it is critical to pull
includes the following: “The need for Because diversity, equity, and inclusion together different perspectives to find
organizational transparency will generate (DEI) is a tough and even controversial the best way to get things done.
growing demand for information on the subject, many shy away from the topic.
ethical implications of the organization’s However, doing so does not help fix Supporting DEI initiatives in our industry
decision-making process.” the disparities marginalized groups helps avoid discrimination for all
face. As these conversations become marginalized populations. Some types
Although they may not seem directly more common, and in turn easier, they of discrimination include:
related to construction, these recent often help maximize the effectiveness • disability,
movements provide an opportunity to of organizations and increase the • race,
consider how creating an inclusive work engagement of team members. • sexual orientation,
environment will help maximize our • gender,
industry’s potential. As more members Sharing a common terminology is • age,
of the Baby Boomer generation retire, helpful when framing discussions of • education level, and
the industry is dealing with more jobs ethics and social justice. Diversity Best • income level.
to fill and a shrinking talent pool. It is Practices has published an extensive
important now more than ever to glossary of terms, 3 including the Creating a DEI plan or incorporating an
consider expanding the industry’s following terms and definitions: ethics policy should be a consideration
diversity and inclusion initiatives—in • Diversity: Psychological, physical, for every organization. Fortunately,
part, to help widen that talent pool. and social differences that occur the construction industry has many
Beyond the bottom-line reasons for among any and all individuals. resources available, and initiatives have
incorporating these types of programs, • Equity: The guarantee of fair already started. Many companies have
regularly having conversations about treatment, access, opportunity, and incorporated aggressive DEI programs
diversity and inclusion issues will help advancement while at the same time that can serve as great case studies.
foster an environment of openness with striving to identify and eliminate Now is the time to start looking at
team members, which has been shown barriers that have prevented the full these resources, implement what works
to improve productivity and employee participation of some groups. for our communities, and share our
retention. • Inclusion: The act of creating successes and failures.
environments in which any individual
According to a 2020 report from the or group can be and feel welcomed, Industry associations are hubs for
U.S. Department of Labor’s Bureau of respected, supported, and valued to relevant information and resources on
Labor Statistics,2 the 2019 demographics fully participate. these subjects and should be leaned
of the labor force were white, 77%; • Implicit bias: Negative associations on regularly. Organizations like the
Black, 13%; and Asian, 6%. The that people unknowingly hold about ASAE4 and the Council of Engineering
report also includes a breakdown by a group of people or individual, and Scientific Society Executives5 have
ethnicity, noting that 18% of the labor expressed automatically and without plan and policy templates available to
force were Hispanics/Latinos, who conscious awareness. [We all have download. In the last several years,
may identify as one or more races; in them; you are not without bias!] communities of practice groups like
this case, 89% of Hispanics/Latinos • BIPOC: An acronym for Black, the Women in Concrete Alliance
reported as white. Occupation and Indigenous, and People of Color. The and Associated General Contractors
10 | ASPIRE Summer 2021EDITOR’S NOTE
This article on diversity and inclusion
as it relates to workforce development
is outside the range of topics usually of America’s Diversity and Inclusion Division of Information and Marketing
covered in ASPIRE®. However, we felt Council have been working to provide Services. December 2020. “BLS
that a perspective on this topic may resources and further initiatives in Reports: Labor Force characteristics
give value to our readers. Members of their respective fields. Advancing by Race and Ethnicity, 2019.” https://
National Concrete Bridge Council (NCBC) Organizational Excellence, a consulting www.bls.gov/opub/reports/race-and-
work with the broader construction firm with association and corporate ethnicity/2019/home.htm
industry and bridge specifiers who clients in our industry, offers a 3. Diversity Best Practices. 2020.
are part of federal, state, and local proprietary benchmarking tool as “Glossary of Diversity, Equity and
agencies. The Slag Cement Association, well as training and plan resources Inclusion Terms.” https://www.
the members of NCBC, and public and specifically for the design and diversitybestpractices.com/sites/
private employers engaged in the bridge construction marketplace.6 diversitybestpractices.com/files/
community are getting more involved in attachments/2020/10/dei_glossary_
diversity, equity, and inclusion initiatives. The construction industry is a unique of_inclusive_terms_updated_
After reading this article, please look sector where we combine science, for_2020_1.pdf
for resources and guidance in your local design, natural resources, and 4. American Society of Association
area and consider, as the author states, community planning. While it may Executives (ASAE) Center for
“incorporating these types of programs sometimes be uncomfortable, we would Association Leadership. n.d.
[by] regularly having conversations be doing ourselves a disservice by not “Diversity + Inclusion.” Accessed
about diversity and inclusion issues being a part of the conversation to M a y 2 0 , 2 0 2 1 . h t t p s : / / w w w.
that will help foster an environment understand how DEI issues impact our asaecenter.org/about-us/diversity-
of openness with team members.” We workforce. These social movements, and and-inclusion
present this article as a call to action, in turn how we collectively respond, will 5. Council of Engineering and Scientific
to do the right thing by expanding impact the people within our industry. Society Executives (CESSE). 2020.
the industry’s diversity and inclusion “Diversity, Equity, & Inclusion
initiatives, and thus make our industry References Resources.” https://www.cesse.org/
more welcoming to a wider range of 1. Cox, J. B., and S. S. Radwan. 2015. dei-resources
our population, providing opportunities ASAE Handbook of Professional 6. Advancing Organizational Excellence
to develop and use the talents of many Practices in Association Management, Diversity Equity and Inclusion
who may not have previously considered 3rd ed. San Francisco, CA: Jossey- Practice Group website. Accessed
working in our bridge industry. Bass. M a y 2 0 , 2 0 2 1 . h t t p s : / / w w w.
2. U.S. Bureau of Labor Statistics, aoeteamdei.com
technical
knowledge
New in
Guide Specification for Grouted Post-Tensioning
2019
Specification for Grouting of PT Structures
certification
ASPIRE Summer 2021 | 11PERSPECTIVE
Perspectives on Structural
Behavior and Redundancy:
Load Path Redundancy
by Dr. Oguzhan Bayrak, University of Texas at Austin
EDITOR’S NOTE ON STRUCTURAL BEHAVIORS SERIES
Robustness, redundancy, resiliency, and ductility of criterion for acceptable bridge designs. For example,
concrete bridges are being discussed by Dr. Bayrak in a concrete breakout failure for embedded anchors is
series of Perspective articles that began in the Summer quite brittle, which is recognized in calibration of the
2020 issue of ASPIRE®. This series is seen by ASPIRE as an applicable equations in the AASHTO LRFD specifications.
important discussion for the concrete bridge community Furthermore, a more complete understanding of
as it begins to consider new materials. These new the actual capacity of a bridge is provided when the
materials have properties that differ significantly from system-level robustness is considered. Different types of
conventional materials, which may lead to different redundancies are inherent in concrete bridges, such as
element behavior. For example, some of the new load transfer between girders; these contribute to the
materials exhibit ductile behavior, whereas others do overall robustness of the bridge by providing multilayer
not. These differences require new approaches to design, protection against sudden failure. However, quantifying
but the framework necessary for establishing these the contribution of these redundancies is not easy.
new design approaches is not clearly defined by current Current AASHTO LRFD specifications have simplified
design specifications. bridge design by considering only element behavior.
Therefore, they do not consider overall system behavior
It should be noted that not all potential failure modes and the redundancies that contribute to it.
considered in the American Association of State
Highway and Transportation Officials’ AASHTO LRFD This article, which is the final article in this series, focuses
Bridge Design Specifications are ductile failure modes, on alternate load paths and structural behavior at all
so ductility should not be considered as the only levels, from section- to system-level behavior.
My article in the Summer 2020 issue this two-cell, post-tensioned concrete at the positive moment region in one
of ASPIRE ® initiated a discussion box-girder bridge. Although the of the three spans. In the event of such
on structural, load path, and internal superstructure was designed to handle extensive damage, this bridge would
redundancies. My subsequent articles a variety of different loads and load benefit from the high torsional strength
in the Winter 2021 and Spring 2021 combinations, an accidental vehicle and stiffness that the undamaged
issues focused on various aspects of strike damaging one of the two cells cell possesses. In the damaged span,
redundancy, resiliency, and robustness of was not explicitly considered in design. one-half of the superstructure would
concrete bridges. This article continues be supported as a cantilever from the
the discussion by focusing on load-path Let us assume an overheight vehicle undamaged cell and use an alternate
redundancy and structural response at striking the bridge would damage all load path that would aid in the transfer
the section, member, and structure levels. internal and external tendons of one cell of the weight of the damaged portion,
Load-Path Redundancy
Load-path redundancy in bridges is the
existence of multiple ways in which
applied loads can be transferred to the
supports. To facilitate a discussion of
load-path redundancy, let us consider
a couple of examples, beginning with Figure 1. If one cell of a two-cell, three-span continuous post-tensioned concrete
a scenario involving a three-span box girder is extensively damaged, the bridge would benefit from the high torsional
continuous post-tensioned bridge. strength and stiffness of the undamaged cell and continuity in the longitudinal
Figure 1 shows the cross section of direction. Figure: Dr. Oguzhan Bayrak.
12 | ASPIRE Summer 2021of the box-girder superstructure as well as
the concrete bridge rail served to mobilize
alternate load paths that prevented
structural collapse.
In the next example, let us consider a
precast and prestressed concrete
girder bridge with the deck supported
on four girder lines. The simply
Figure 2. Severe damage to a two-cell, Figure 3. Severe damage to a prestressed
supported span was damaged by
post-tensioned concrete box-girder concrete beam bridge caused by an
an overheight vehicle strike, severely
bridge from an overheight vehicle strike. overheight vehicle strike. Load-path
damaging the bottom flange and
The stiffness of the remaining box-girder redundancy within the multibeam
superstructure prevented structural
web of the fascia girder (Fig. 3). system prevented collapse. Photo: Mark
collapse. Photo: Kansas Department of
The adjacent girder was damaged to a Bloschock.
Transportation.
lesser extent. Figure 4 illustrates two
alternate load paths that likely helped The reinforcement details, use of partial-
and any loads placed on it, into the the bridge survive the vehicle strike and depth precast concrete panels, and
supports. Although this bridge was associated damage that was not explicitly the like, are all controlled by applicable
not designed to accommodate such a considered in the original design. service and strength limit states of the
loading scenario, a vehicle strike would American Association of State Highway
likely not result in collapse. The alternate Alternate load path 1 (Fig. 4a) requires and Transportation Officials’ AASHTO
load path is facilitated by continuity in the deck to work as a cantilever to pick LRFD Bridge Design Specifications. 1
the longitudinal direction, by the well- up the load (from the location marked However, when called upon, the top and
distributed post-tensioning layout, and as “a” in Fig. 4a) that was originally bottom mat reinforcement in the deck
by the torsional stiffness and strength of supported by the fascia girder (beam will serve to reinforce the cantilever to
the undamaged cell. 1) and transfer it to beam 2 (along the transfer the load. Second, bridge rails
path marked as “b” in Fig. 4a). Beam 2 are designed for vehicle impact, and
Figure 2 shows an example similar to subsequently carries the load to bents 1 their design purpose is to keep vehicles
that described in Fig. 1; in this example, and 2 (using the paths marked as “c” in on the bridge. To meet their intended
the boom of an excavator that was being Fig. 4a). Alternate load path 2 (Fig. 4b) design function, the rails are crash-
transported by truck severed the great involves the overhang portion of the tested to verify their design. Once again,
majority of the longitudinal reinforcement deck taking the load (from the location when the need arises, as it does in this
near a support. In this case, the stiffness marked as “a” in Fig. 4b) that was vehicle-strike scenario, the rails can serve
1 originally supported by the fascia girder as a substitute for the fascia girder and
t
Ben (beam 1) over to the bridge rail (along provide an alternate load path, even
c the path marked as “b” in Fig. 4b). The when the rails are jointed.
Bea
m 2 bridge rail now works as the new fascia
c girder carrying the load to bents 1 and In summary, a bridge’s actual behavior
t 2
Bea b Ben 2 (along the paths marked as “c” in Fig. is dictated by the structural details
m 1
4b, although the load may also go back provided in that bridge. For example,
a in the aforementioned case, deck
into the girder and into the supports
at undamaged locations). In reality, the reinforcement that is primarily intended
load will be shared by a combination to resist cracking caused by volume
of both of these alternate load paths. changes due to temperature and
(a) Alternate Load Path 1 shrinkage can readily serve as flexural
The member that displays the larger
t1 reinforcement in a cantilever. There is no
Ben stiffness will attract a greater portion of
the load that was originally carried by replacement for good structural details,
Bea the fascia girder. robust reinforcement detailing, and
m 2
c good conceptual designs.
Rai 2
l t
Bea c Ben Undoubtedly, the distribution of forces
m 1
b
is a function of material strengths Section-, Component-, and
a as well as the bridge geometry—for System-Level Responses
Previous articles in this series focused
example, beam spacing, girder depth,
on the relationship among the sectional
and bridge rail geometry. Depending
response, the response of a potential
on the aforementioned factors, the rail
(b) Alternate Load Path 2 plastic hinge, and the member-level
may play a more or less important role
response. We also examined the
Figure 4. As a result of redundancies, two compared to the slab cantilevering to
influence of structural redundancy
alternative load paths are available after pick up the load. Having acknowledged
on overall response. The previously
a fascia girder, represented in the figure that subtlety, we must recognize two
discussed overheight vehicle strike
as beam 1, is heavily damaged near important points. First, bridge decks are
cases provide the framework for our
midspan. Figure: Dr. Oguzhan Bayrak. never designed for this type of loading.
ASPIRE Summer 2021 | 13thinking regarding primary (intended) to making decisions on the safe side, Implementation of
and secondary (alternate or backup) and understandably so. In many cases, System-Level Behavior
load paths in cases where unexpected and especially within the context of The preceding discussion describes
conditions challenge a bridge’s ability behavioral failure modes at the element how our design and load-rating
to support permanent and applied level, this approach is easy to follow. specifications have recognized the
loads. The presence of primary and If one decides to play on the safe side importance of structural, load-path, and
secondary load paths results in a robust for every step of the evaluation moving internal redundancies for quite some
structural response where a concrete from a cross section to a plastic hinge, time. Next, let us explore an example
bridge can make use of a variety of then to a component, and finally to that demonstrates the implementation
different load paths under different the system level, an accumulation of of these concepts in our specifications,
loading or damage scenarios. Ultimately, conservative assumptions may introduce such as the load rating of segmental
the system-level response is the most considerable statistical bias in estimating bridges (See the Spring 2021 issue of
important. With that said, there are a the system-level response. ASPIRE for an article on load rating
variety of ways to obtain an abundantly segmental bridges.). Table 1 shows that
redundant concrete bridge system Alternatively, and as was done in the the system factor ϕs, in this case for
displaying a robust structural response. AASHTO Guide Manual for Condition post-tensioned segmental concrete box-
The cases discussed previously provide Evaluation and Load and Resistance girder bridges, is a function of several
good examples of robust structural Factor Rating (LRFR) of Highway variables, including the bridge type and
response where local damage was Bridges,2 a more systematic approach construction method. In effect, the
contained and did not progress into aimed at minimizing statistical bias system factor is intended to reflect the
structural collapse. and targeting appropriate levels of presence of alternate load paths and
reliability (as measured by reliability give credit to more-redundant structural
The AASHTO LFRD specifications were index β) for the inventory (design) rating systems. The second column shows that
calibrated using a reliability-based (β = 3.5) and operating (load rating) the determinacy (structural redundancy)
methodology to ensure a reasonably rating (β = 2.5) can be used. Concepts influences the system factor, with the
uniform level of component safety. For underpinning the philosophy adopted third column explicitly indicating the
typical concrete bridge systems ranging in the AASHTO LRFR, and later in the reasoning. For example, a statically
from simple to complex, there is a AASHTO Manual for Bridge Evaluation,3 determinate span needs to form one
relationship between the component- are discussed in many publications. hinge to establish a collapse mechanism;
level and system-level responses. In a Weed 4 provides a concise discussion an end span of a continuous unit needs
reliability-based framework, accurate of this topic. There are a number of to form two. (For details on plastic
capacity estimations with minimal additional guidance documents hinges, see the article in this series
statistical bias, both for load and that acknowledge and implement in the Winter 2021 issue of ASPIRE.)
deformation capacities, will lead to a reliability-based framework to load With respect to internal redundancy, as
better estimations at the system level. rate concrete bridges. For example, the seen in the last columns of the table,
Florida Department of Transportation as the number of tendons in each web
The importance of minimizing statistical commissioned studies to establish increases, so does ϕs. Furthermore, the
bias cannot be overemphasized. rational load-rating procedures for their impact of this redundancy on ϕs is quite
Engineers are typically predisposed segmental and spliced girder bridges.5,6 significant and is nonlinear, as can be
Table 1. System factors for single-cell, post-tensioned segmental concrete box-girder bridges
Number of System factors (ϕs)
Bridge type Span type hinges to Number of tendons per web
failure 1 2 3 4
Precast balanced-cantilever, Interior span 3 0.90 1.05 1.15 1.20
Type A joints End or hinge span 2 0.85 1.00 1.10 1.15
Statically determinate 1 n/a 0.90 1.00 1.10
Precast span-by-span, Interior span 3 n/a 1.00 1.10 1.20
Type A joints End or hinge span 2 n/a 0.95 1.05 1.15
Statically determinate 1 n/a n/a 1.00 1.10
Precast span-by-span, Interior span 3 n/a 1.00 1.10 1.20
Type B joints End or hinge span 2 n/a 0.95 1.05 1.15
Statically determinate 1 n/a n/a 1.00 1.10
Cast-in-place balanced-cantilever Interior span 3 0.90 1.05 1.15 1.20
End or hinge span 2 0.85 1.00 1.10 1.15
Statically determinate 1 n/a 0.90 1.00 1.10
Note: For box-girder bridges with three or more webs, table values may be increased by 0.10. Adapted by Dr. Oguzhan Bayrak from references 2, 5, and 6.
14 | ASPIRE Summer 2021You can also read
