Monday, October 19, 2020
W01: Bridge Preservation: An Integral Element in the Transportation Asset Management Plan
Richard Dunne, GPI, Lebanon, NJ
Time: 8:00 – 11:30 AM
Many workshops/sessions at IBC provide strategies on how to design and construct bridges for maximum service life. This workshop will identify bridge preservation strategies to extend the service life of existing bridges. Part One will focus on bridge deck preservation, which is most exposed element of a bridge. Part Two will discuss superstructure and substructure preservation strategies. This workshop is aimed at providing bridge owners/designers/contractors proven methods to shift from bridge builders to bridge preservers.
W02: Strut and Tie modeling
Francesco M. Russo, Ph.D., P.E., Michael Baker International, Philadelphia, PA
Time: 8:00 AM – 12:00 Noon
Building on a successful and well-attended / reviewed 2018 workshop, Introduction to Strut-and-Tie Modeling, the presenters will provide a brief overview of more recent developments in the area of strut and tie modeling of concrete structures and provide details on the successful application of the technique to a variety of more complex design and rehabilitation projects. Included are discussions on the application of strut and tie modeling to the evaluation of box girder hinge joints, the evaluation of integral cap beams in multi-cell concrete box girders, the use of conventional and strut and tie modeling approaches for the assessment of concrete pier caps with in-service cracking, evaluation and design approaches for large concrete footings, and the development of computer-aided design approaches for new multi-column framed bridge piers. Prior to the case study presentation, an overview of the AASHTO specifications will be provided along with the presentation of a simple design example to provide an introduction to the materials.
W03: Domestic Scan 19-01 “Leading Practices for Detailing Bridge Ends and Approach Pavements to Limit Distress and Deterioration”
Bijan Khaleghi, Washington State DOT, Turnwater, WA
Time: 10:00 AM – 12:00 Noon
Faced with an aging infrastructure and limited resources, transportation agencies seek ways to minimize maintenance and repair costs to their inventory. Agencies identify bridge deck joints as a high cost item, in terms of maintenance and potential for adjacent bridge member damage. Therefore, one concept to increase inventory sustainability is to minimize the number of joints in the structure. While moving joints off the bridge has improved structural durability, thermal expansion and contraction of the structure once accommodated at deck joints is now all transferred to the bridge ends.Detailing and maintaining joints at bridge ends is notoriously challenging. The transition from one structure to another often becomes noticeable to road users as a “bump at the end of the bridge”. Additionally, thee displacements and forces at these locations are particularly prone to cause damage to riding surfaces and structural elements. Bridge owners have adopted a wide variety of design details to avoid this damage and have sought to understand the causes of observed distress.
Time: 8:30 AM – 12:00 Noon
IBC 20-01: Substructure Rehabilitation using Galvanic Encasement of the Frederick G Gardiner Expressway
Rachel Stiffler, Vector Corrosion, Canonsburg, PA; David Whitmore, P.E., Vector Corrosion, Winnepeg, MB Canada
Toronto, the capital of the province of Ontario, Canada and fourth largest city in North America unfortunately, also lays claim to some of the worst traffic. The biggest culprit behind this traffic gridlock is The Frederick G. Gardiner Expressway, commonly known as the Gardiner Expressway. It runs East/West at the very south end of the city. The condition of the highway has deteriorated over the 50+ years of its existance. The structure has been described as an out-of-date, crumbling and frequently traffic-jammed freeway. Extensive repairs became necessary in the early 1990s, and significant commercial and residential development has occurred in the core. As a result, the Gardiner Expressway has been the subject of several proposals to demolish it, or move it underground as part of downtown waterfront revitalization efforts. The primary cause of the aforementioned “crumbling” was clearly chloride induced corrosion…. And when left unchecked, chloride induced corrosion can lead to major structural problems. As an alternative to demolition and replacement, a viable option is to repair and protect the severely deteriorated structure utilizing a galvanic encasement that both structurally upgrades and cathodically protects the structure. Galvanic cathodic protection provides an effective low maintenance option for engineers and owners of infrastructure. Preservation of the structure using a galvanic encasement combined with an overlay of self consolidating concrete won the debate and work has begun and is scheduled to be completed in early 2021. The deck replacement will take place over the next 10 years. This paper will present the “Gardiner Expressway” project case study on the use of galvanic encasements to repair and protect reinforced concrete structures providing effective cathodic protection for 20 to 40+ years.
IBC 20-02: Landslide Prevention for High Speed Rail Bridges on a Steep Slope with Pressed-in Pipe Piles
Takefumi Takuma, Giken Ltd., Orlando, FL; Koji Kajino, Giken Ltd., Kochi, Kochi Japan; Masashi Nagano, Giken America Corp., New York, NY
The Japanese government is extending a high speed rail line on the westernmost major island of Kyushu toward the city of Nagasaki. The route goes through one of its mountainous sections where landslides are expected due to their steep slopes and highly weathered mudstone underlain by a sloped bedrock. A 370m (1,213ft)-long multi-span pre-stressed concrete girder bridge required landslide prevention on a flank of the steep slope. In order to achieve the landslide preventing function without having to build a major construction road on the unstable slope, the rotary press-in piling method was selected to haul, pitch, and install 31.0 to 43.5m (103 to 143ft) long, 1,200mm (47.2 in) diameter steel pipe piles from the top of previously installed piles. Two rows of piles spaced at 2D on center were staggered to allow the groundwater to migrate through the piles at three different locations of the slope. Each pile had a cutting shoe welded at its toe for speedy installation and was rotated and simultaneously pressed into soil on the slope through the bedrock thereunder. The pile installation was successfully completed in what was otherwise a very difficult construction operation with a high level of safety with the rotary press-in piling machine and a clamp crane; both of which firmly clamped onto the previously driven piles without sitting on the unstable and steep slope. Depending on a bridge project’s needs, a steel pipe pile wall can be made watertight or very porous but with a high level of rigidity as exemplified on this case study project.
IBC 20-03: Weekend Deck Replacements of Four Interstate Bridges Utilizing a Simple Precast Deck System
John Gonyea, Fort Miller, Schuylerville, NY; Eddie He, Ph.D., P.E., S.E., AccelBridge, Hinsdale, IL
The Colchester Bridges Project was a rehabilitation of four existing bridges carrying I-89, at one of the busiest segments in Vermont. To minimize traffic impact, the deck replacement of each bridge must be completed in one weekend, opens to traffic on Monday morning. AccelBridge was selected for the project due to its durability, speed and simplicity in construction. The two key features of the deck system are: match-cast epoxy joints between precast deck panels and deck compression by jacking against supporting girders without the use of post- tensioning. By eliminating cast-in-place joint between panels, this deck system offers significant savings in materials, field labor and schedule. Deck panel erection consists only two simple tasks, applying epoxy to the match cast joint and pulling the panels together by winches. The average erection rate of this project is about 20 minutes per panel. Enhanced durability was achieved by compressed match- cast deck units with no rebar or PT across the joint, thus no corrosion potentials. The project execution was successful and safe. Deck replacement of each bridge was completed within one weekend closure. All panel joints in the project were closed very nicely without any repair and only minimal geometry adjustments. Project experience validated that this deck system is straightforward and fast to construct, needing only conventional materials and equipment.
IBC 20-04: Monitoring of First Circular (reusable) Bridge
Chris Fielding, DYWIDAG, Bolingbrook, IL
The Dutch Government for Infrastructure, Rijkswaterstaat, has the ambition to work ‘circular’ (i.e. reusable) by 2030. This means that the traditional way of working, including the way bridges are built, is no longer applicable. The lifecycle process from design stage to execution and through demolition needs to change.
The circular bridge engineers designed a bridge that utilizes standardized concrete blocks that have a 200 year lifespan. These blocks are connected like Lego pieces and are posttensioned (PT) in the longitudinal and transversal directions. Then, after the lifespan of the bridge is complete (~40 years), these blocks can be de-installed and re-used again at another location, hence the term ‘circular’.
A pilot circular bridge was built using this concept, and it was necessary to monitor the performance of the bridge to validate the design principles and to overcome the rule that posttensioning always needs to be bonded in the structure. This, in the Eurocode, is called ‘design by testing’. In order to validate, an Infrastructure Health Monitoring (IHM) system was installed and consisted of several components; camera control of the vehicles passing, direction and speed of vehicles, temperatures, bending of the bridge, and the bird-gapping between the blocks. Also, as part of the IHM system, alerts and alarms were programmed to be sent to the engineers if measurements exceeded pre- defined thresholds. This presentation will provide a conceptual overview of the circular bridge approach with a focus on the IHM system used to validate the design principles.
IBC 20-05: Withdrawn
IBC 20-06: Remote Radar Monitoring for Bridge Load Testing and Stay Cable Forces
Larry Olson and Patrick Miller, Olson Engineering, Inc., Wheat Ridge, CO
As the nation’s infrastructure continues to age, and traffic congestion continues to increase, the rapid load rating of highway bridges is becoming a necessity. Presented herein are case studies in which static and dynamic deflections of typical highway bridges were measured with a non-contacting interferometric radar system (IBIS-S). The bridges were monitored during both normal traffic loading and known weight, slow rolling load testing. The Interferometric radar system (IBIS-S) can simultaneously measure the displacement and vibration responses of multiple locations of a structure from distances up to 0.5 kilometer. The IBIS-S system has a maximum accuracy of 0.01 mm (0.0004 inch) and a maximum sampling frequency of 200 Hz (Nyquist frequency of 100 Hz). The system is tripod mounted and can be rapidly deployed, allowing load testing in a matter of hours. The non-contacting nature of the system can, in some instances, provide measurements in otherwise difficult access situations.
Results are presented for nondestructive evaluation (NDE) of the tension forces in concrete bridges/stay cables during/after construction using high frequency radar. Structural health monitoring (SHM) of displacements and vibrations of bridges/stay cables is now possible remotely with non-contacting interferometric phase radar. Stay cable forces are determined from the multiple resonant frequencies associated with stay cables under tension from ambient vibration sources such as wind/traffic or physical excitation of stay cables. The technical advantages of the radar technology versus laser lidar and conventional accelerometer/strain gage measurements include remote measurements up to 500 m for 0 Hz (static) to 40 Hz vibration frequencies, simultaneous measurements of displacements/vibrations of multiple stay cables and steel cross beam as well as concrete bridges with metal corner reflectors that can be readily installed, rapid field testing and setup, and measurements are independent of weather conditions.