Engineers' Society of Western Pennsylvania


337 Fourth Avenue
Pittsburgh, PA 15222

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Tuesday, June 4, 2024

Technical Sessions

Suspension-Rehabilitation Design 1

Time: 8:00-10:00 AM

IBC 24-07: Pittsburgh’s Three Sisters Bridges Rehabilitation-Historic Bridge Rehabilitation Lessons Learned
Aaron Colorito, P.E., Michael Baker International, Moon Township, PA ; Michael Burdelsky, P.E., Allegheny County DPW, Pittsburgh, PA

Pittsburgh’s historic Three Sisters Bridges (6th, 7th, and 9th Street) over the Allegheny River are nearing the completion of three rehabilitation projects that began in 2016. Although nearly identical in design, detailing, and construction, they have experienced age and deterioration in different ways. Numerous structural repairs were detailed throughout the rehabilitations to address different types of deterioration, damage, and deficient load-carrying capacity. These and other repair strategies are presented for structural steel, concrete, and masonry repair, including the challenging process of cleaning decades of soot and soil from the distinctive masonry substructure units of all three bridges. Challenges encountered during the rehabilitation projects are discussed from a designer’s and owner’s perspective.

IBC 24-08: Repair & Rehabilitation of Historic Suspension Bridges Great & Small
Benjamin Reeve, P.E., Structural Technologies/VSL, Fort Worth, TX

Suspension bridges of all sizes and uses are elegant accents across our transportation landscape. As longstanding engineering marvels, these ornate structures have a unique set of maintenance aspects. This discussion will be on the construction, monitoring/inspection, rehabilitation, and lessons learned on suspension bridges of all types and sizes. Recent rehabilitation projects discussed will include (original construction):
• Ambassador Bridge (1929; 1850 ft main span)
• Waco Suspension Bridge (1870; 475 ft main span)
• Missouri River Pipeline Suspension Bridge (1956; 457 ft span)
• Leo Frigo Memorial Bridge (1981; 450 ft span)
• Jefferson Barracks Bridge (1983, 1992; 909 ft span)

The discussion will involve suspended bridges spanning over 100 years of construction, touching on technologies used to monitor them through their service life, as well as rehabilitate the structures for increased demands while maintaining their historical significance. Monitoring and inspection technologies will include non-destructive (e.g. magnetic main flux method (MMFM)) and destructive (e.g. load capacity testing) test methods. Rehabilitation aspects to be discussed will include the replacement of the entire suspension system and will primarily focus on the suspender cables. While the basic structural design aspect of these bridges from throughout history is the same, there are particular similarities and differences between these suspension bridges of different sizes and transportation requirements that will be highlighted. Structural Technologies/VSL’s experience in suspended spans provides the background, pictures and methods for this discussion.

IBC 24-09: Suspension Bridge Rehabilitation and Preservation Constructability Challenges
Joshua Pudleiner, P.E., STSC, AECOM, Philadelphia, PA ; James Mandala, P.E., AECOM, New York, NY ; Barry Colford, AECOM, Philadelphia, PA

There are 51 long span suspension bridges carrying vehicular traffic in North America. Of that number 50% of them are over 75 years old and 80% of them are over 50 years old. The US, has the oldest major cable suspension bridge inventory in the world with an average age of 73 years. The older of these bridges includes Williamsburg (1903), Brooklyn (1883) and Roebling (1867) with Wheeling (1849) being the oldest in the U.S.
As they get older, the inspection, maintenance, preservation and rehabilitation of these bridges becomes even more vital as the majority of them carry critical infrastructure routes and their closure or even partial closure would cause significant disruption and have an adverse economic effect. Therefore, it is essential that they are well managed and maintained.
Over the past two to three years additional funding has been made available to owners of some of these bridges and there is a large program of work being undertaken to ensure and in cases extend the service life of these bridges.
This paper will examine some of the constructability issues faced by engineers when carrying out projects to preserve, rehabilitate or replace elements of these suspension bridges. These include:
• Suspender ropes testing and replacement
• Hand ropes and stanchion post testing and replacement
• Main cable internal wire inspection
• Main cable dehumidification
• Anchorage dehumidification
• Cable band bolt re-tensioning and replacement
• Main cable saddle bent bolt replacement

IBC 24-10: Rehabilitation of the 1870/1914 Waco Suspension Bridge
Patrick Sparks, P.E., Sparks Engineering, Inc., San Antonio, TX; Zach Webb, P.E., Lost Art Structures, Austin, TX

The landmark Waco Suspension Bridge was completed in January 1870, located at the Brazos River on the Chisholm Trail. It was designed by engineer Thomas Griffith of New York, who had previously worked at the Roebling company.
In 1914, the bridge was fully rehabilitated by the Missouri Valley Bridge and Iron Company. In that major project, the bridge was strengthened and widened. The bridge served for vehicular traffic until 1971 when it was restricted to pedestrian use.

In 2018, a number of critical conditions were identified, including a significant loss of strength in the suspension cables, corrosion and improper past repairs of the anchor rods, non-functioning saddle bearings, recurrent cracking in the towers, and deterioration of the wood deck.

The current rehabilitation project, completed in April 2023, involved complete replacement of the suspension cable system and anchors, improvements to the anchorages, sliding saddle bearings, strengthening the towers, and new decking. This paper describes the many challenges of investigation, diagnosis, rehabilitation design and construction of this landmark rehabilitation.

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Materials & Research

Time: 8:00-10:00 AM

IBC 24-11: Strengthening of White Bayou Bridge with FRP Composites
Vijaya Gopu, Ph.D., P.E., LTRC & University of Louisiana, Baton Rouge, LA; Walid Alaywan, Louisiana Transportation Research Center, Baton Rouge, LA

The aging infrastructure in the U.S. is requiring the use of innovative and cost-effective ways to repair, rehabilitation and upgrading of reinforced concrete bridges. FRP (Fiber Reinforced Polymers) strengthening systems are increasingly being deployed to accomplish this task. Weight restrictions on existing bridges caused by either the deterioration that has occured over the service life of the bridge or the change in the vehicle axle loads are harmful to commerce. The lack of resources to replace bridges that have exceeded their design service life has resulted in the aging bridges having to be kept serviceable by utilizing practical strengthening systems. Numerous research studies have been conducted in the U.S. over the past two decades to study various aspects of the FRP strengthening systems including the influence of these strengthening systems on the bridge behavior under service and ultimate loads, strength and stiffness, failure mechanisms, and durability of the repair. This paper presents the results of a project involving the implementation of three different CFRP strengthening schemes on an existing concrete bridge near Zachary, Louisiana. Details of the strengthening schemes are provided and the results of the load testing before and after strengethening are discussed. The load test results are compared with those predicted by finite element analysis of the bridge and the impact of the strengthening systems on load rating of the bridge are examined. Details of the long-term monitoring system installed on the bridge to assess the durability of the strengthening systems are presented .

IBC 24-12: Performance of Carbon Fiber Strand in a Maine Cable Stay Bridge
Jeff Folsom, P.E., Maine DOT, Augusta, ME; Chris Burgess, P.E., S.E., GM2, Inc., Highlands Ranch, CO

MaineDOT in association with FHWA used federal IBRC funds in 2006 to implement a Demonstration Project for evaluating carbon fiber strands in bridges. The program involved installation of representative carbon fiber strands in cable stays of the Penobscot Narrows Bridge and Observatory in Maine.

The bridge uses a cradle system to carry stays from bridge deck through the pylon and back to bridge deck. All strands are independently placed in each stay, thus strands may be individually removed, inspected, and replaced while the bridge carries traffic. This feature provided an opportunity to install and monitor representative carbon fiber strands in the cable stays. Carbon fiber strands were installed for the purpose of assessing long-term performance during in-service conditions and evaluating for use on future bridges.

All the bridge stays were designed to each include two additional reference strands. Six epoxy coated steel strands (2 each in a short, medium, and longer stay) were successfully replaced with carbon fiber strands in June 2007. Data is collected from monitoring equipment installed on all strands (both traditional steel strand and carbon fiber) in the bridge to evaluate carbon fiber performance for future bridge post-tensioning installations. The bridge location in Maine ensures that test strands will be evaluated under a wide range of temperatures and wind loads.

Background will be shared about carbon fiber stay strand installation along with results from inspection and load monitoring that has been performed since 2007 through the most recent results to be obtained in November 2023.

IBC 24-13: Industry Engagement Survey for UHPC Beam End Encasement Options for the Construction of New Steel Bridges
Brian Lassy, E.I.T., University of Connecticut, Storrs, CT; Alexandra Hain, University of Connecticut, Storrs, CT; Sarira Motaref, University of Connecticut, Storrs, CT

The corrosion of steel girder ends presents a significant challenge to the maintenance of bridges, incurring substantial cost and time investments. In response to this issue, the Connecticut Department of Transportation (CTDOT) and the University of Connecticut (UConn) jointly developed a solution utilizing Ultra-High Performance Concrete (UHPC) beam end encasement. This repair method has been tested over ten years of research and is currently being implemented for 40 bridge rehabilitation projects in Connecticut. Due to its success, UConn and CTDOT are expanding the beam end encasement method to new bridge construction. The proposed design replaces a conventional steel bearing stiffener with a UHPC bearing column serving as both a structural element and protective encasement for the beam end, and includes details to integrate this new method into the construction process to ensure cohesion with CTDOT’s standard designs. This study will propose several innovative connection details between UHPC bearing columns and standardized steel K-frame diaphragms and present a comprehensive beam end design tailored to a sample bridge. This paper will also present an industry engagement survey that was conducted to evaluate the structural integrity, cost-effectiveness, and constructability of the connections between steel diaphragms and UHPC bearing columns. By engaging with industry experts in the development and evaluation of new construction methods, the results of this study will provide a highly applicable tool to aid in the nation’s goal of building a more resilient transportation network.

IBC 24-14: Can the Application of Higher Strength and Corrosion Resistant Reinforcement Improve the Crack Control Performance of Bridge Decks and Provide Improved Durability and Service-Life? An Illinois DOT Case Study will be Presented.
Salem Faza, Ph.D., CMC, Irvine, CA; Tom Russo, CMC; Maher Tadros, eConstruct USA

This bridge pilot was the first use of ASTM A1035 LCCR on an IDOT project.
ASTM A1035 is marketed by CMC as “comparable” to stainless steel rebar (SSR) when the required durability and service life of a bridge deck is 100 years to the first major repair. The focus of the Illinois Bridge Engineers in applying ASTM A1035 at fy 80 ksi was to determine if a higher strength design would provide a more efficient and less costly application as compared to their typically used ECR designed bridge decks. Since this bridge selected allows a side-by-side comparison, actual installed cost was collected and compared to determine the final cost premium for a 100 year service life deck when using LCCR versus ECR.
This paper will include the design parameters as well as the results derived from the AASHTO crack control equations.
Using this ILDOT bridge findings, cost comparison estimates to other types of corrosion resistant reinforcement such as A1094, A767, and A955 would be illustrated. Characterization of the effect of bond strength on the concrete/bar system to control the crack width and service life of the structure.

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Cable Stay

Time: 8:00-10:00 AM

IBC 24-15: Load Rating of The Gerald Desmond Bridge
Javier Campos, P.E., S.E., Arup, Los Angeles, CA

The Gerald Desmond Bridge Replacement is a 2000-foot cable stayed bridge with two 515-foot tall mono-pole towers. The super-structure cross-section consists of steel-box edge girders composite with light-weight precast concrete deck panels. The approach structures consist of single and multi-cell prestressed concrete box girders.

This paper focuses on the methodology and procedures used to analyze and load rate California’s first long-span signature cable stay bridge. The load rating underpins the structure’s 100-year design life through extensive construction stage analysis, integrating numerous construction documents throughout the life of the project, explicit modeling of locked-in construction effects and compatibility between the as-built cable stayed bridge and site survey information.

The concrete approaches also presented their own load rating challenges, using a MSS construction methodology with locked-in effects that affect the calculations. Lastly, this paper will focus on the non-conventional rating of complex structures, aspects not explicitly covered in the MBE, and rating of elements not typically covered on standard bridges. Understanding the bridge design intent, and interpreting code provisions made this a noteworthy challenge to the load rating team.

IBC 24-16: Construction engineering of the US 181 Harbor Bridge Replacement main spans
Quentin Marzari, P.E., S.E., Arup, San Francisco, CA ; Jonathan Aylwin, Arup, Corpus Christi, TX; Manuel Contreras Pietri, CFC USA, Miami Beach, FL; Javier Campos, Arup, Los Angeles, CA; Luke Tarasuik, Arup, New York, NY

The main spans of the US181 New Harbor Bridge currently under construction will replace the 66-year-old crossing over Corpus Christi, TX shipping channel. With a length of 3,289’, a central span of 1,661’, and a width under 149’, once complete, it will be the longest cable-stayed bridge in the USA, the longest precast segmental span and widest delta frame bridge in the world.

The construction engineering of such a structure called for special attention, particularly when considering the geometry control of the bridge and the site-specific wind hazard.

Erection is performed with precast components hoisted near the towers and delivered by SPMTs to the cantilever front. A derrick crane then lifts the segments/delta frames into position with a manipulator fine-tuning the geometry.

The cable pretensions are carefully tuned to balance loading in different parts of the bridge with the objective of ensuring stresses are acceptable during construction and in-service, as well as limiting the sensitivity of the structure to uncertainties in creep behavior.

Geometry control includes matching the vertical profile to the roadway geometry, as well as correcting for twisting and other minor deformations inherent in the erection sequence.

With a relatively stiff superstructure, geometry adjustment for on-site variations through force is generally inefficient. Consequently, geometry control is mostly achieved using cast-in-place joints every 100’ to 140’. This requires proper coordination between the erection engineering, survey, and construction teams to meet the targeted geometry.

Temporary works at closure locations provide moment fixity to protect the in-situ closure joints during curing.

IBC 24-17: Case Study of the Rehabilitation and Preservation of Two Ohio River Cable Stay Bridges
Dallas Montgomery P.E., P.L.S., ASTM-PTI, Burgess & Niple, Inc., Louisville, KY; Scott Ribble P.E., Burgess & Niple, Inc., Louisville, KY

The Kentucky Transportation Cabinet (KYTC) recognized significant deficiencies in two of their cable stay (CS) bridges across the Ohio River. They retained Burgess & Niple (B&N) to inspect, perform non-destructive testing (NDT), generate rehabilitation plans for extending the service life, provide construction oversite during rehabilitation, and preservation of the two structures. This is a case study of the interesting and pertinent details of the project. The William H. Natcher CS Bridge is 4,505 feet in length and 67 feet wide. It is supported by 96 stay cables connected to two identical diamond-shaped towers: each 374 feet tall. At the time of its construction in 2002, it was the ’ longest stay cable-supported bridge over an inland waterway. The William H. Harsha Bridge is 2,420 feet in length, from abutment to abutment. The superstructure is supported by 80 stay cables connected to two identical H shaped towers. Project is on-going.

IBC 24-18: I-395 Signature Bridge – Construction Engineering of Precast Arches and Stayed Spans
Harry McElroy, P.E., McNary Bergeron and Johannesen, Broomfield, CO

The I-395 Signature Bridge consists of six precast segmental concrete arches radial to a center pier from which independent eastbound and westbound cast-in-place concrete superstructures are suspended. These are the first precast segmental arches done in the US since Natchez Trace 30 years ago. Unique details were developed for arch erection, including specialized precast molds, self-consolidating concrete, temporary tie-backs and towers, lifting details, and erection post-tensioning. A congested construction site in downtown Miami presented logistical constraints requiring staged arch and deck activities. Four of the arches will be constructed initially to suspend the westbound superstructure. Then traffic will shift from the old bridge to the new westbound, making way for construction of remaining arches and eastbound superstructure. Asymmetric alignment made no two suspenders alike in orientation. A full 4D non-linear staged construction analysis was used to determine the safest and most economical way to cast westbound and eastbound superstructures on falsework and hang them from the arches by engaging suspenders. In summer 2022 Archer Western de Moya began erecting arch segments.

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Innovative Construction Techniques

Time: 8:00-10:00 AM

IBC 24-19: Protection Level 3 application on Internal PT for large precast segmental bridge
Alban Drouault, VSL International, Bern, Switzerland; Faical Batine, VSL Systems Ltd, London United Kingdom; Frederic Turlier, VSL Systems Ltd, London, United Kingdom; Marwan El Jamous, VSL Systems Ltd, London, United Kingdom; Jean-Baptiste Domage, VSL International, Bern, Switzerland

The deck is composed of 1000 No. precast concrete segments. The depth of each box girder varies between 3m and 6.7m, weighting from 60 to 140 tons, and the deck width is constant at 13.4m
Segments are cast following the match cast method, using 3 casting cells that can be adapted to different heights and to all types of segments, from typical and deviator segments to segments on piers and end segments.
Segments are installed following the balance cantilever method using a launching gantry.
The gantry measures 150 meters in length, 18 meters in height, and has a weight of 700 tons with a lifting capacity of 140 tons. It allows for the simultaneous assembly of a pair of segments using the balanced cantilever method. Wind tunnel tests on a scale model were conducted to justify its ability to withstand storm-induced wind loads.
The project’s distinctive feature lies in the development and implementation of the prestressing system to meet the project’s strict durability requirements, particularly at the joints between prefabricated elements. The internal post-tensioning system ensures the protection level 3 (PL3) with a sealed encapsulation of the cables.
This system establishes electrical isolation between the prestressing cables and the adjacent reinforcing cage, and it is the measurement of this electrical resistance that allows for the monitoring of the PT integrity at all stages of the structure’s lifespan.
This is the first full application of a PL3 system with segmental coupler on such a large-scale structure.

IBC 24-20: Preliminary Fatigue Evaluation of a 100-Year-old Double Level Bridge
Richard Stevens, P.E., and Rasmin Kharva, P.E., Hardesty & Hanover, New York, NY

The Long Island Railroad (LIRR) Double Deck Bridge is multi-level structure carrying ten tracks over the Van Wyck Expressway – a busy corridor leading to JFK airport in Queens, New York. The superstructure system consists of riveted steel framed construction. Portions of the structure over the highway right-of-way are owned by New York State (NYS) DOT, while structure over railroad property is owned by LIRR.

The NYSDOT recently set out to construct two new multi-use lanes on the Van Wyck Expressway, requiring relocation of the lower portion of three column lines supporting this multi-level structure. A complex rehabilitation and load path reconfiguration scheme was developed, preserving much of the existing upper level of the structure to minimize long term impacts to commuter service.

A major fatigue assessment was conducted by NYSDOT and Hardesty & Hanover to compute the expended fatigue life of existing members and estimate the remaining fatigue life under future movements. The fatigue assessment calculations were conducted based on Miner’s Rule, AREMA 2017 parameters, and live load stress ranges computed from the model. To further supplement the analysis, a comprehensive strain gage program was conducted where selected girders were instrumented. This paper/presentation will provide the results of the assessment, key factors that made the assessment successful, and lessons learned and recommendations for optimization of future fatigue evaluation.

IBC 24-21: Predicting Bridge Health: Machine Learning-Based Condition Rating from Element-Level Inspections
Zeinab Bandpey, Morgan State University, Baltimore, MD; Ruel Sabellano, P.E., M. ASCE, Morgan State University, Baltimore, MD; Mehdi Shokouhian, Ph.D., Morgan State University, Baltimore, MD

Effectivity of transportation networks rely on the condition of bridge infrastructure. There are more than 617,000 bridges across the US and about 7.5% of these are considered to have structurally “poor” condition. The State Departments of Transportation (DOTs) have been collecting total quantities and quantities associated with condition states for the National Bridge Elements (NBEs), Bridge Management Elements (BMEs), and Agency Developed Elements, also known as element-level data since 2015.
The objective of this study is to develop a data-driven approach to evaluate conditions of small and medium span bridges and propose new prediction models based on the existing Element Level data and FHWA bridge inspection data.
Structure Inventory and Appraisal (SI&A), element level data, and NOAA weather data from 2015 to 2021 for 2,199 steel bridges were employed, and inconsistent or missing data were identified, cleaned, and processed. The processed data was used to carry out a preliminary analysis to identify the most influential variables on deteriorating a Steel bridge. Several Machine Learning models were examined to find the most suitable prediction model with the highest accuracy for bridge deterioration. This model is instrumental in aiding decision-makers to accurately predict bridge condition and effectively allocate funds for bridge management.

IBC 24-22: An Overview of the I-95 Bridge Collapse, Emergency Repairs, and Bridge Replacement
Joseph Sirignano, P.E., VMA, Benesch, Allentown, PA; Amelia Harris, Ph.D., P.E., Benesch, Cranberry Township, PA; Din Abazi, P.E., Pennsylvania DOT, King of Prussia, PA

In June 2023, a fiery truck crash collapsed the I-95 northbound bridge, carrying 160,000 vehicles daily, over the Cottman Avenue off-ramp in Philadelphia, PA. The southbound structure was compromised and demolished. Reconstruction entails a temporary roadway – designed and constructed in 12 days utilizing ultra-lightweight foamed glass aggregate fill, precast barriers, and wire walls – and the permanent bridge replacement which includes two single-span skewed steel bridges. Critical and immediate design decisions influenced all phases.

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Suspension-Rehabilitation Design 2

Time: 10:30 AM – 12:00 Noon

IBC 24-23: Proposed Improvements to North American Main Cable Dehumidification Systems
Jonathan Morey, P.E., WSP USA, Edgewood, MD; Stuart Rankin, WSP USA, New York, NY

Over the past 10 years, main cable dehumidification systems have been installed on select suspension bridges across North America. The performance of these systems in achieving the desired objective of maintaining exhaust readings less than 40% Relative Humidity has been inconsistent. As there is presently no code governing the application of dehumidification systems, WSP has compiled observations through involvement in the design, installation, operation, and maintenance of 8 suspension bridge cable dehumidification systems. By comparing variables across bridges, from resistance to flow within cables, to control and monitoring integration with mechanical equipment, and comparing these observations with systems elsewhere that have a proven history of performance, WSP has developed improvements that should be applied to future dehumidification systems and may be included on existing systems through retrofits. The most critical improvement to the main cable dehumidification system layout is the number of air changes per hour that will take place, which is predicated based on the distance between injection and exhaust locations. A target volume of air circulating through the main cable of 3.5 Air-Changes-per-Hour (ACH), at an injection pressure of 12”w.c., assuming reasonable Loss of Flow along the cable length and Cable Void Ratios, will overcome the non-homogeneous conditions, as well as variables associated with resistance to flow along the length of the cable. Additional improvements to mechanical equipment, locations of exhaust sensors to avoid outside interference from wind, purge valves at low points of dry air piping and the use of gate valves for balancing will be discussed.

IBC 24-24: Deck Replacement and Strengthening of the Throgs Neck Bridge
Roger Haight, P.E., ENV SP, WSP USA, New York, NY ; Courtney Clark, P.E., Thornton Tomasetti, New York, NY; Edmond Knightly, P.E., MTA Bridges & Tunnels, New York, NY; Yimin Chen, P.E., MTA Bridges & Tunnels, New York, NY

The Throgs Neck Bridge (TNB) in New York City is a steel suspension bridge with total length of 2,848 ft. The roadway deck was replaced, and the superstructure was strengthened.

The existing deck on the suspended span of TNB was a concrete-filled grid deck system supported on stringers that provided nearly 60 years of service. Project goals for the new deck included: a lighter system to reduced dead loads; staged construction; and providing a minimum of 75 years of service life. To meet these goals, a new steel orthotropic deck was designed to replace the existing deck. A life-cycle-cost-based approach was used to evaluate three deck alternates: one orthotropic deck alternate, and two filled-grid-deck alternates. The life cycle cost comparison accounted for both the longevity of the orthotropic deck components and the reduced maintenance for elements below the deck due to the jointless configuration. Also critical was for the deck alternative to accommodate staged construction.

For this heavily trafficked bridge, maintaining flow was a key requirement for the deck replacement project. In order to most effectively stage the construction and maintain traffic, multiple staging scenarios were considered to coordinate stage lines for consistent rib spacing and to match longitudinal splices for shop fabrication, along with considering the effects on the deck during the intermediate stages. Staging involved design of temporary median crossovers. Cast-in-place composite deck placed at the anchorage and tower spans used high-performance internally-cured (HPIC) concrete, now standard for roadway decks in New York State.

Since the new orthotropic deck is composite with the stiffening trusses, strengthening/ rehabilitation included addition of shear connectors between orthotropic deck and stiffening trusses and stiffening truss strengthening, all coordinated with the staged construction. New tower span stringers, new concrete-span bearings and pedestals, custom floor truss and stiffening truss gusset plate strengthening and repairs, new median and fascia barriers, new modular expansion joints, electrical and lighting upgrades, and new NFPA-compliant dry standpipe system were also included. Key site conditions included, among others, developing a successful, cost-effective, and constructible strategy among owner, contractor, and designer for addressing pack rust deformations in the existing stiffening truss bottom chord built-up section that caused challenges in installing strengthening plates.

IBC 24-25: Completion of First UHPC Deck Rehabilitation on Entire Suspension Bridge
Sam Boukaram, P.E., and Michael McDonagh, WSP USA, Lawrenceville, NJ; Shekhar Scindia, Delaware River and Bay Authority, New Castle, DE; Abate Tewelde, P.E., HNTB, Lawrenceville, NJ

The Delaware River and Bay Authority (DRBA) now has a UHPC overlay on the entire deck of it’s 2-mile-long Delaware Memorial Bridge first structure. The UHPC was installed as a replacement of the top layer of the deck to avoid increasing the weight. This is the first suspension bridge with a complete UHPC overlay in the United States and possibly in the world. The presentation will cover how project transpired and the challenges encountered.

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Construction Engineering 1

Time: 10:30 AM-12:00 Noon

IBC 24-26: Construction of the US 60 Bridge over the Cumberland River
Taylor Perkins, Ph.D., P.E., S.E., Stantec Consulting, Lexington, KY; Austin Hart, Kentucky Transportation Cabinet, Paducah, KY

The existing Lucy Jefferson Lewis Memorial Bridge in Smithland, Kentucky carries US 60 traffic over the Cumberland River. This crossing serves as an essential connector for Livingston County and the narrow typical section and imposed weight restrictions of this 90 year-old structure were no longer satisfying the needs of the community. Consequently, in 2015, the Kentucky Transportation Cabinet awarded a contract to design a replacement.

The replacement structure consists of a 700-ft simple-span truss main unit, the third longest in North America, with PPC I-beam approach spans. This paper discusses the construction challenges of the project, which included installation of large foundations in this high seismic region and mitigation of high-water impacts in this floodplain of the Ohio and Cumberland Rivers. The highlight of the construction was the truss float-in. Located in a difficult s-curving stretch of the Cumberland River, the bridge site presented challenges to the erection of the truss. With temporary support restrictions from the USCG and nearby ROW and archeological constraints the Contractor was forced to seek a feasible erection location off-site. Fortunately, an agreement was struck between an under-utilized riverport facility in Paducah, KY and the Contractor to the mutual benefit of both parties. Although 15 miles downriver from the project site, the Riverport facility had the perfect infrastructure for staging and erecting the truss. In September of 2022, the 700-ft truss span was floated from the Riverport facility in Paducah to the project site in Smithland and lifted into place.

IBC 24-27: Brightline Trains Florida: Rail Structure and Construction Innovations over 160 miles of Railroad
Scott Dean, P.E., Kyle Ervin, P.E., and Ryan Rapp, P.E., S.E., HNTB, Lake Mary, FL; Michael Leonard, P.E., Colliers Engineering & Design, Jacksonville, FL

The $4.5B rail system built by Brightline Trains Florida, LLC, which connects Central and South Florida, includes 65 structures utilizing a wide variety of structure types. This paper provides an overview of structure types used, the challenges of constructing in an active freight corridor, and the development of and lessons learned from the use of prestressed concrete deck beams with UHPC. Brightline’s acceptance of the alternate technical concept of jacked concrete tunnels is also discussed.

IBC 24-28: High-Load Jacking for Truss Bearing Replacement at the Pulaski Skyway
Qi Ye, P.E., CHI Consulting Engineers, Summit, NJ; Steven Htet, CHI Consulting Engineers, Summit, NJ; Yujan (Albert) Zhang, CHI Consulting Engineers, Summit, NJ; Liwei Han, CHI Consulting Engineers, Summit, NJ

Under Contract 8B, the steel bearings on Piers 44 to 56 of the Pulaski Skyway are slated for replacement with new HLMR bearings, totaling 34 bearing replacements. Each of these bearings is designed to support substantial dead and live loads, with the peak load reactions for a single bearing reaching around 1,100 tons for dead loads and 290 tons for live loads.

To ensure a seamless and safe replacement of the steel bearings, CHI Consulting Engineers introduced cutting-edge jacking frames and temporary supports. These include temporary diagonal members incorporated within the existing trusses and triangular frames positioned atop the existing concrete steps at the pinnacle of pile caps. For expansion piers, the design integrates temporary sliding bearings.

By October 2023, 12 of the existing bearings have been successfully elevated and replaced. Notably, the most challenging lift was at Pier 43, where an astounding 4.6 million lbs of jacking force was applied to hoist the two trusses from the pier. This achievement underscores the strength and effectiveness of the support systems developed by CHI.

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Design & Analysis-Innovation

Time: 10:30 AM – 12:00 Noon

IBC 24-29: Triple I-Girder, Integral Steel Straddle Bent Application for I-10/US69 Beaumont Eastex
Ahmed Rageh, Ph.D., P.E., Volkert, Tallahassee, FL; Christopher White, P.E., HNTB, Houston, TX;  Feifei Bai, Volkert, Houston, TX

To enhance redundancy and eliminate frequent and costly inspections of fracture-critical steel structures, Volkert worked with TxDOT Bridge Division to develop a triple I-beam, system-redundant integral steel bent cap solution. Design utilized a two-step approach: (1) Overall section design in accordance with AASHTO “LRFD BDS” using a 3-D FEM beam model; and (2) 3-D nonlinear FEM shell analyses to design girder/cap connections and verify system redundancy requirements using AASHTO/NSBA “Guide Specification GSFCM-1-UL”.

IBC 24-30: Pocket Track Viaduct Pier Strengthening and Rehabilitation
Bradford Shaffer, P.E., S.E., AECOM, Seattle, WA; Mark Henry, P.E., WMATA; Elliott Mandel, P.E., AECOM, Arlington, VA; Thomas Trapnell, P.E., AECOM, Richmond, VA; Rez Lotfi, Ph.D., P.E., AECOM, Arlington, VA

Three piers along the WMATA D&G Junction viaduct were issued a change order to accommodate the future extension of the center pocket track. This extension is improve rail operations by allowing an 8 car train to wait before crossing between the Orange and Blue Lines. The retrofit was based on providing a redundancy of the anchor bolts, already at Fatigue Life, at the top of the column by providing a post-tensioned concrete cap. For the extension, these caps at each of these 3 piers were increased in size to accommodate an additional steel box girder. The strengthening involved short post-tensioned tendons coupled with steel plates and post-tensioned bars to contain the splitting forces around the existing columns. Finite element MIDAS models were developed along with emphasis on constructability detailing to help facilitate the implementation by the contractor. Direct work with the contractor on RFIs have improved the intended final product.

IBC 24-31: Data-Driven Preventive Maintenance and Service Life Increase of the Sunshine Skyway Bridge – Tampa FL, USA
Ivan Gualtero, P.E., Atiq Alvi, and Steve Womble, TYLin, Tampa, FL; Vincent Collie, P.E., Florida DOT, Tampa,FL

The Sunshine Skyway Bridge was opened to traffic in 1987. This remarkable structure is a cable-stayed structure with a Main Span Length of 1,200 ft and a 4,000 ft Main unit with a total of 11 spans. The bridge is now reaching half of its design service life and its owner (the Florida Department of Transportation) is putting a lot of effort into extending the service life of the bridge. This paper describes the Data-Driven Preventive Maintenance and Service Life Increase approach that is being applied to this bridge. This innovative approach implemented by T.Y. Lin includes Structural Monitoring with almost 100 sensors, composed of a balanced mix of conventional SHM sensors combined with custom-built sensors tailor-made for the specific monitoring needs of this structure. Parallel to monitoring, we are implementing a Finite Element Model that will be an accurate representation of the as-built structure and will be calibrated with sensor data creating a true Digital Twin of the structure. The Digital Twin will help to better understand the structural behavior of the bridge and will provide vital data for determining the remaining service life of a very critical component like the stay cables and the stay cable dampers. The data obtained from the sensors is post-processed using the latest techniques in “Big Data” processing and is currently being used to train a Machine Learning model that soon will help accurately predict in real-time structural parameters allowing the identification in real-time any parameter that is outside its normal limits.

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Design & Analysis

Time: 10:30 AM – 12:00 Noon

IBC 24-32: Existing Pier Evaluation using Non-Linear Composite Concrete Modeling
Tony Shkurti, Ph.D., P.E., S.E., HNTB, Woodridge, IL; Angela Kingsley, P.E., HNTB, Minneapolis, MN

MnDOT contracted with HNTB in 2020 to provide advanced analyses for pier evaluation and repair design at Bridge 9217 carrying T.H. 494 over the Minnesota River. The hammerhead piers were designed prior to the use of modern detailing practices and the introduction of code provisions such as the general method for shear design or the strut-and-tie method for D-regions. Leaking joints over much of the bridge’s service life had resulted in long periods of drainage on the piers below, causing widespread deterioration. Assessment of remaining pier capacity was needed to define strengthening needs.
HNTB used a specialty nonlinear finite element analysis program to accurately assess pier behavior and capacity. Based on Modified Compression Field Theory (MCFT) and the Disturbed Stress Field Model (DSFM), the analysis is capable of capturing concrete cracking and stress redistribution between concrete and rebars, capturing nonlinear behavior of the materials such as compression softening due to transverse cracking, tension stiffening, shear slip along the cracked surfaces and consideration of the deterioration effects and repair such as material nonlinear expansion, confinement and clamping effects, rebar bond slip, and cover spalling.
Nonlinear pier analyses were performed using 2D elements incorporating both smeared and discrete bar elements for reinforcement modeling. Force-based analyses were run starting with loading determined by a refined superstructure model and loads were increased in 5-10% increments until the pier could not carry any additional loading. The analysis results showed all possible failure modes and captured the

IBC 24-33: Rehabilitation of the LA 47 over Intracoastal Waterway Gulf Outlet
Michael Paul and Durk Krone, P.E., TRC Engineers, Inc., Baton Rouge, LA

TRC was responsible for the development of preliminary and final plans to address the repair and rehabilitation of all substructure and superstructure elements of this historically designated bridge consisting of 1,248 feet of steel main spans with cantilevered arms and a tied arch (main span); 3,304 feet of welded steel girder approaches; 1,590 feet of prestressed girder approach spans; and 480 feet of concrete slab spans for a total bridge length of 6,622 feet.
Work items associated with the rehabilitation and cleaning and painting of the structure were initially defined using previous NBIS inspection reports, non-destructive testing reports, load rating reports, and as-built and widening plans. During the final design, TRC conducting a focused inspection and bridge washing to verify and quantify repair locations. 3D laser scanning was also conducted during the final design to determine which pier(s) translatedr movements to cause excessive finger joint movements at the main spans. Rehabilitation items included cleaning and painting all structural metalwork, safety cable installation, MMA deck sealer, FRP concrete repair, LMC inlay deck repair, heat straitening impacted truss members and retrofitting the truss to accommodating pier movements.

IBC 24-34: Design of the Main Span for the Bogota MRT Line Viaduct
Rajan Chaurasia, P.Eng., WSP Canada, Mississaugua, ON Canada; Max Nie, WSP Canada, Burlington, ON Canada

The Bogota metropolitan area suffers from the world’s most severe rush-hour traffic congestion, surpassing major cities like Manila, Mumbai, and Tokyo. The planned first Metro Line is a 24km long elevated Mass Rapid Transit (MRT) line featuring 16 stations, along with a depot. The WSP Global teams are awarded as the project’s lead consulting, while WSP Canada teams have been tasked with designing the viaduct structures. The entire elevated viaduct consisting of 750 spans would be built using span-by-span segmental construction. This paper presents the challenges encountered in the design of the main span (215m) long viaduct taking into consideration a range of design codes.
The three-span (57.5m + 100m +57.5m) viaduct carrying 2 pairs of LRT (Light Rail Train) tracks was designed using a balanced cantilever construction method. The primary design code was Colombian Bridge Design Standard – LRFD (CCP 14), which is heavily based on AASHTO LRFD Bridge Design Specifications – 2012. However, several other design codes, such as the latest AASHTO, ACI, and Eurocode, were also incorporated to address other load cases like train live load and associated load cases like hunting, longitudinal, and rolling forces, including train derailment, broken rail, and rail structure interaction. As the design advanced, the design criteria underwent changes to reconcile conflicts arising from the incompatibility of these design codes.

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W03: AASHTO COBS Workshop

Chair: Margaret A. Jackson, P.E., Pennsylvania DOT, Montoursville, PA

Time: 8:00 AM – 12:00 PM

This workshop is sponsored by the AASHTO Committee on Bridges and Structures (COBS) Advisory Committee to the IBC. The Advisory Committee works in cooperation with the IBC to help COBS address their priorities, particularly about advancing the bridge state-of-the-art and effectively implementing new and updated AASHTO bridge specifications. As represented in the agenda below, the workshop agenda features recent work from various COBS technical committees.

Introduction and AASHTO COBS Update:

  • Bernie Carrasco, PE – Texas Department of Transportation (10 Minutes)

Asset Management:

  • Bernie Carrasco, PE – Texas Department of Transportation (15 Minutes)

Bridge Preservation Technical Committee:

  • Graham Bettis, PE – Texas Department of Transportation (15 minutes)

Knowledge Management Workforce Development:

  • Graham Bettis, PE – Texas Department of Transportation (10 minutes)

Bridge Components:

  • Tom Murphy, PhD, PE, SE – Modjeski and Masters (10 minutes)


  • AASHTO Concrete Committee Update
  • AASHTO Guide Spec
    • Tom Murphy, PhD, PE, SE – Modjeski and Masters (30 minutes)

Safety and Evaluation:

  • AASHTO Guidance Document for NCHRP 12-122
    • Proposed AASHTO Guidelines for Applications of Unmanned Aerial Systems Technologies for Element-Level Bridge Inspection
      • Alicia McConnell, PE, sUAS – AM3 Consultants (30 minutes)

Soil Structures: 

  • Section 10 rewrite
    • Scott Hidden, PE – North Carolina Department of Transportation (40 minutes)

Specialized Structures:

  • LRFD Guide Specification for the Design of FRP Pedestrian Bridges 2nd Edition
    • Gregg Blaszak, PE – Coastline Composites (15 minutes)

Steel and Metals:

  • Steel and Metal
    • Brandon Chavel, PhD, PE – Michael Baker International (40 minutes)
  • Welding and Fabrication Spec Update
    • Heather Gilmer, PE – Pennoni (20 minutes)


W04: Ensuring Safety and Planning for what might seem unlikely during construction
Zachary Taylor, P.Eng., P.E., Ph.D., Rowan, Williams, Davies & Irwin, Inc., Guelph, ON, Canada

Time: 8:00 – 11:30 AM

New long span cable stayed and suspension bridges are routinely analyzed for the effect of the wind and extreme weather conditions during the design phase. However, all bridges regardless of their mass and stiffness are more susceptible to the effects of wind and weather conditions during construction phases whether that be for construction of a new bridge, or construction work necessary to maintain or rehabilitate a bridge.
Bridges are at their most vulnerable during construction phases. Bridge movement due to tarping or placement of traffic barriers on existing bridges may seem unbelievable until it is seen in videos on social media platforms. Aerodynamic and bridge-specific climate analyses before construction can predict when this might happen.
We propose to organize a 3-company, 3-hour workshop in which we will explore the potential vulnerabilities of various types of bridges during the construction phase, how to analyze construction stages for potential issues and how to mitigate those issues through damping bridge decks, cables, and arches. This live demonstration will show the analyses, the scale model wind tunnel testing, the mitigation analyses done using numerical simulations and the dynamic response of the bridges with and without damping.
The case studies will feature the construction of a new arch bridge, cable stayed bridge and rehabilitation of a suspension bridge, steel truss bridge, and cable stayed bridge. RWDI (the bridge aerodynamic consultant, Motioneering (the damping consultant) and a construction engineer will each present their unique perspectives about potential issues during bridge construction and the mitigation methods.