Tuesday, June 11, 2019
Construction 2/Cable Stayed Session
Time: 1:30 – 5:00 PM
Session Chair: Brian Kozy
Delivery of complex projects such as arch and cable stayed bridges affords the opportunity for engineers and owners to think outside the box, push the envelope, and advance the state of the practice. This session covers a number of complex bridge projects where new methods were used in contracting, design, construction, aesthetic treatment, or inspection.
IBC 19-27: Contractor Manager/General Contractor (CMGC) Delivery of a Tied Steel Arch Bridge Re-Decking
Jonathan Eberle, P.E., AECOM, Mechanicsburg, PA ; John Milius, AECOM, Philadelphia, PA ; Paul Kettleson, Minnesota DOT, Oakdale, MN ; Steve Kaldenbach, Kraemer North America, Burnsville, MN
The use of an alternate delivery method allowed the rehabilitation and re-decking of the Smith Avenue Bridge (High Bridge) to be designed and constructed under an accelerated schedule. The Minnesota Department of Transportation (MnDOT) elected to use the Construction Manager/General Contractor (CMGC) alternate delivery method for this project with the rehabilitation design completed by AECOM and the construction completed by Kraemer North America. The High Bridge, which spans the Mississippi River in St. Paul, Minnesota, consists of 3 continuous tied steel arch main spans measuring 282’-3”, 520’ and 241’-9” with multi girder steel approaches on either side of the main spans. The bridge was originally constructed in 1987 and due to deteriorating deck condition, a comprehensive rehabilitation including deck replacement was necessary. The tie members of the arch spans, which connect at the crowns of the arches, are each comprised of four post tensioning tendons which were sequentially stressed during the original construction. To allow for re-decking, these tendons needed to be removed and replaced during the rehabilitation. This complexity led to the need for advanced construction analyses to be completed for the structure including development of a staged construction sequence. The sequence for construction and loads utilized within the analyses were determined through coordination between the designer and contractor, a benefit of the CMGC process. This paper will discuss the advantages and lessons learned regarding the use of the CMGC process for this project.
IBC 19-28: NEXT beam bridges for 100 plus year service life
Jianwei Huang Ph.D., P.E., Southern Illinois University Edwardsville, Edwardsville, IL
The Prestressed/Precast Concrete Institute (PCI) Northeast recently developed a novel bridge beam section called the northeast extreme tee (NEXT) beam, which provides several advantages over the traditional I-shaped and adjacent box beams. The use of NEXT beams can accelerate bridge construction process by saving time on beam erection; meanwhile, the top flange of the NEXT beam can act as formwork for the cast-in-place reinforced concrete (RC) deck, saving time and cost on building/stripping the deck concrete formwork. NEXT beam bridges have been adopted in bridge replacement projects in the states of Vermont, Maine, Massachusetts, and New York. In order to achieve a bridge system that can last over 100 plus year service life, in this presentation a hybrid reinforced concrete deck is proposed to be used in the NEXT beam bridges. The use of hybrid deck reinforcements in the concrete deck in NEXT beam bridges can achieve a durable bridge system, in which GFRP and steel rebars are used as top and bottom reinforcements, respectively, in the concrete deck. Adopting the top GFRP reinforcements solve the steel corrosion problem, which results from the use of deicing salts for snow/ice removals in northern American regions in winter. The design and durability of a hybrid deck is discussed, providing useful insights on the design of NEXT beam bridge decks for practicing engineers.
IBC 19-29: Curtis Creek Bridge Rehabilitation CM/GC
Donald Marinelli, P.E., Hardesty & Hanover, Annapolis, MD ; William Pines, P.E., Maryland Transportation Authority, Baltimore, MD
MDTA Procurement and H&H worked to develop the bid documents to set the qualifications and requirements for evaluating and selecting a Construction Manager (CM). Innovation was needed in developing the contractual documents that incorporated the technical challenges associated with the movable bridge rehabilitation, and allow for advanced design and procurement of long lead time items for specialty mechanical and electrical items. H&H and the CM developed phased construction strategies to maintain vessel and vehicular traffic on I-695 during the rehabilitation. Benefits from the innovation in design and project delivery were realized, including: contracting a highly qualified CM to perform the work, the ability to modify the design details and project scope in order to meet the construction schedule, reduce and/or eliminate change orders and the ability to manage the Guaranteed Maximum Price (GMP) to stay within the project budget.
IBC 19-30: New Bridge on Crati River
Silvia Geyer, Claudio Pin and Daniela Lombardini, Redaelli Tecna, Cologno Monzese, Milano, Italy
The new bridge on Crati River is an iconic project that underline the contemporary desire of the city of Cosenza, one of the most avant-garde cities in the region of Calabria. The new bridge it is not only a functional infrastructure that aims to connect and sew two very socially and structurally different urban areas, but it also, with its audacious architecture, aims to become a symbolic and distinguishing monument of the city. Designed by Santiago Calatrava and realized by CIMOLAI construction company, it is a stay cable bridge characterized by a single inclined pylon 85-meter-high, inclined at 40° from the vertical plane of the bridge. Upon first glance, the structure remember a large harp, supporting the steel of the main deck which itself spans a railway and the river. The main span is 110 meters with a total length of the bridge of 140 meters. The predilection of becoming a symbol is accentuates by the fact that the bridge is visible from every part of the city even from the old town located over the adjacent hill. Redaelli’s contribution to this land marking structure includes cables supply, engineering of cable installation and tensioning and all related site activities. The stay cables supplied are different diameters in order to optimize forces and weights; the total mass of cable supplied is 96 tons.
IBC 19-31: A Beacon of Coastal Beauty – Inspired by Community Vision
William Johnson, IV, P.E., SE, Figg Bridge Engineers, Inc., Exton, PA
The Harbor Bridge project was developed by the Texas Department of Transportation to maximize mobility and connectivity; enhance port access and marine navigation; facilitate hurricane evacuation; enhance economic opportunity; and improve safety by replacing the existing bridge and surrounding roadways. The new US 181 Harbor Bridge includes concrete box girders for a 7,535’ long, high-level approach bridge superstructure with 180’ typical spans, a 3,295’ long cable stayed main span superstructure unit with a cable stay tower height of 538’-2” and 205’ vertical navigational clearance. Keeping towers and foundations completely out of the waterway means a record-setting 1,661’ span using today’s proven concrete cable-stayed technology. FIGG’s patented cable-stayed cradle system will be placed in the towers. Individual strands can be removed easily under moving traffic providing safe and efficient inspection and maintenance. The single towers use a single plane of dual, companion stays that streamline efficiency above the deck. Below the deck, an A-Frame tower distributes the loads providing structure advantages and creating smaller, economical footings. The bridge has a shared use path and overlook to add interest for the local public and visitors. The Belvedere overlook features an educational and cultural viewing space along with unique benches for visitors to experience the beauty of the natural environment. The Developer is committed to achieving Platinum INVEST sustainability ratings for project development, operations, and maintenance. Some project sustainability features include solar lighting for pavers and recycled crushed concrete as landscape accents.
IBC 19-32: Design & Construction of the Shimla Cable Stayed Bridge
Lucas Wise, CPEng. And Mithun Mohan, Systra – International Bridge Technologies, Jumeirah Lakes Towers, Dubai United Arab Emirates
The new Shimla Bypass cable stayed bridge forms part of the 27 km four lane development of the proposed Shoghi – Shimla – Dhalli bypass of National Highway 22 in the northern state of Himachal Pradesh, India. The 586m long bridge is located at the foothills of the Himalayan range at an elevation of 2,000m above sea level. The bridge is subjected to several complex site constraints, both geographical and environmental, in-particular ground accelerations over 1.0g and high wind loads that are affected by the surrounding topography. The project is being developed through BIM, which is one of the first cable stayed bridges in India that will be fully developed and delivered using this approach. The limitations of the valley resulted in an unsymmetrical 3 span cable stayed bridge supporting a 26.9m wide dual carriageway, with spans of 100m-318m-168m. The bridge will be built in balanced cantilever, in which individual elements are pre-fabricated on the deck and are progressively erected using a lifting frame. The final deck level is over 200m above the valley below. Each carriageway is supported by a plane of stay cables and consists of a composite structure of steel edge girders and floor beams with precast concrete deck panels. The unique single mast concrete pylons house the anchorages for the two planes of cables. The pylons reach a height of about 215m above the valley, with the upper 40m reserved for the composite steel-concrete stay anchorage housings.
IBC 19-33: Suspender Cable Inspection Using Advanced Robotic Technology at Arrigoni Bridge
Muhammad Asif Iqbal, P.E., LEED Green Associate and Aslam Siddiqui, P.E., AI Engineers, Inc., Middletown, CT ; Doug Thaler, P.E., Infrastructure Preservation Corporation, Washington, DC ; Gregory Funk, P.E., Connecticut DOT, Newington, CT
This paper covers the suspender cable inspection using advanced robotic technology RopeScan® and determining the actual tension forces of the suspension cables under deadload condition using Laser Vibrometer at Arrigoni Bridge 00524 without any interference to the traffic and minimal inconvenience to the traveling public. The Arrigoni Bridge is a thirty (30) span steel through arch structure carrying Route 66 over Route 9, the Providence and Worcester Railroad and the Connecticut River between Middletown and Portland, Connecticut. Opened in 1938, the 1,200 feet (370 m) bridge was the most expensive bridge ever built in Connecticut, at a cost of $3.5 million. Its two distinctive 600 feet (180 m) steel arches have the longest span length of any bridge in the state. AI Engineers, Inc., (AI) was tasked by the Connecticut Department of Transportation (ConnDOT) to perform the suspender cables using the non-destructive method which is electromagnetic in nature, more commonly known as; Magnetic Flux Leakage (MFL) and determining the tension forces of the suspender ropes which connect the bottom chords of the through-truss to the floor beams of the Arrigoni Bridge. AI with the help of Infrastructure Preservation Corporation (IPC)., performed the inspection using RopeScan Robotic Inspection System. RopeScan is a stand-alone, battery operated, self-propelled wireless inspection system. RopeScan uses a clamshell approach to attach to the ropes. A handheld remote control the ascend and descend of RopeScan as it performs an inspection using MFL. The purpose of this MFL inspection was to establish the overall condition of the suspension ropes, determine the presence any abnormal condition, such as; the presence of corrosion, loss of metallic section, broken wires, and the extent of same, within metallic area of the suspender ropes, and locate & document any and all issues of concern within the suspension ropes for future comparison within a comprehensive inspection report.
The tension forces in the suspension cables were determined using a Laser Vibrometer Type PSV-150 under deadload condition. We used the forced excitation method to reduce the measurement time to a minimum and to allow excitation of multiple notes. A Stochastic Subspace Identification (SSI) method was used to overcome the frequency resolution limit of a Fast Fourier Transformation (FFT).
Preservation 2 Session
Time: 1:30 – 5:00 PM
Session Chair: Gary Runco
Room: Woodrow Wilson A
From old Steel Trusses built in 1815 to a new replacement bridge, this 2nd, Preservation 2, session focuses on preserving the actual structure or the context sensitive setting of an old bridge. Participants will learn a little bit of everything as it relates to analysis methods, choice of materials and construction methods. Both small (200’) and large (2400’) bridges are included as well as those fabricated from timber, stone, steel and concrete.
IBC 19-34: Rehabilitation of an Historic Phoenix Column Truss Bridge Due to Vehicular Collision
John Baumgardner, P.E., HDR, Inc., Plymouth Meeting, PA ; Monica Harrower, Henry Berman, P.E. and Din Abazi, P.E., Pennsylvania DOT, King of Prussia, PA
The Ross Fording Road Bridge, built in 1885, is an historic single span Phoenix column pony truss connecting picturesque farming communities in Chester and Lancaster Counties. Following a vehicular impact to the bridge, PennDOT District 6-0 mobilized an emergency response and significant resources to save this bridge from complete collapse. The subsequent rehabilitation project was developed to restore the function of the bridge, protect the structure from future vehicle impacts and preserve the historic integrity of the structure. The rehabilitation of the damaged upstream truss included replacement of a Phoenix column end post, bottom chord members, vertical member angles and lateral bracing. To mimic the appearance of the Phoenix column end post, the rehabilitation detailed a member consisting of a steel tube with four flanges attached by welds. Rivets were placed through the flanges with spacing to match that of the existing members. Other details of the existing structure, including the irregular eye bar shapes, were carefully measured in the field and detailed on the plans to match the appearance of the existing members to the greatest extent possible. The rehabilitation design of the bridge included a detailed step-by-step procedure to maintain the temporary support of the truss during the repairs and lifting of the truss back to its proper position. The Section 106 process, including Consulting Party and State Historic Preservation Office involvement, was performed on an accelerated schedule to minimize the duration of the bridge closure due to the vehicular impact damage.
IBC 19-35: Lightweight Superstructure Replacement of the Bridge Carrying Baltimore Harbor Tunnel Thruway Over Patapsco River Flats
Shilpa Kodkani, P.E., Christine Szympruch, P.E., and Robert Healy, P.E., Rummel Klepper and Kahl, Baltimore, MD ; William Pines, P.E., Maryland Transportation Authority, Nottingham, MD ; Joseph Hoffmann, P.E., McLean Contracting Company, Glen Burnie, MD
The Patapsco Flats Bridge is located on the Maryland Transportation Authority’s Baltimore Harbor Tunnel Facility and carries I-895 over Patapsco River Flats. The dual bridge was built in 1957 and is 2380’ long with 42 simple spans in each bridge. The existing bridge superstructure was in poor condition. RK&K evaluated various superstructure rehabilitation and replacement options. The design team’s goal was to create a durable superstructure and reduce the number of joints while using the existing substructure. Due to the limited capacity of the substructure, a light weight superstructure had to be designed. The final design consisted of a full superstructure replacement with steel plate girders carrying a steel grid deck partially filled with all light weight concrete with a density of 100 pcf. The number of joints was reduced by 50% resulting in a more durable bridge. The project was awarded to McLean Contracting Company in 2016 and is currently under construction. The bridge is located over marsh and water, and the desire to keep construction out of environmentally sensitive areas have made construction challenging. McLean developed a method utilizing temporary spans supported on the substructure to facilitate all construction from the bridge. McLean is also repurposing the old bridge materials for a fish reef off Love Point in the Chesapeake Bay. This paper will discuss the design and construction of this challenging bridge superstructure replacement project with the perspectives of the entire project team including the Owner, Designer and Contractor.
IBC 19-36: Adams Avenue Historic Arch Structure Rehabilitation
Christopher Bentz, P.E. and Ronald Krolick, P.E., Alfred Benesch and Company, Pottsville, PA; Monica Harrower, Din Abazi, P.E. and Henry Berman, Pennsylvania DOT, King of Prussia, PA
The scope of work was to rehabilitate the three-span stone masonry arch bridge which carries Adams Avenue (SR 1002) over Tacony Creek. The bridge was built circa 1815 and reconstructed in 1901 and 1942 and is listed in the National Register of Historic Places. This bridge features variations commonly found on other Pennsylvania Stone Arch bridges. The arched section is recessed, piers are pyramidal in shape; the parapet wall is constructed of smaller stones than the spandrel walls; and the parapets are capped with a course of unfinished, projecting stones. This stylistic combination is unique. Based on the findings of inspections, structural analysis and current design standards, the design consultant developed a rehabilitation program.
The improvements involved removing the pavement and backfill over the stone arch barrels and repairing the arch. The existing parapets and deteriorated sections of the spandrel walls and wingwalls were removed and rebuilt. Excess stones were salvaged for reuse. A concrete saddle was constructed over the stone arches to provide additional load-carrying capacity. Upon completion of repairs, lightweight concrete was placed on top of the arch barrels between the spandrel walls, to the underside of the pavement. New reinforced concrete moment slabs with integral concrete core parapets were constructed on top of the lightweight concrete. The salvaged stone was utilized as a decorative facing on the concrete core parapets. Since the quantity of salvaged existing stone was not sufficient, new stone that closely matches the existing stone was interspersed with the existing stone.
IBC 19-37: Design and Construction of Blenheim Covered Bridge
Sean James, P.E. and Josif Bicja, P.E., Hoyle, Tanner & Associates, Inc., Manchester, NH
The Old Blenheim Bridge was a single-span, double-barrel Long Truss wooden covered bridge built in 1855 located in North Blenheim, NY and destroyed by flooding of Tropical Storm Irene in 2011. The Long Truss was patented in 1830 by US Army Engineer Col. Stephen Long and is considered to be the first intentionally prestressed truss bridge. This paper will detail the analysis, design and construction of the replacement bridge. The replacement bridge, constructed in 2018, is one of the longest single-span covered bridges in the world and one of only six double-barrel covered bridges in the country. The total length of the bridge is 228′ with a clear span of 200′ and includes three trusses, one of which utilizes a built-in timber arch. The bridge was ultimately designed utilizing LRFD codes, however a full analysis was completed and compared utilizing both ASD and LRFD methods. The unique design included prestressing of the bridge through a detailed preloading sequence of the trusses with water-filled containers at approximately 64% of its dead load or 228 kips. Truss counter diagonals, which were installed after the preloading, were loaded in compression as the preload was removed from the bridge. The sustained compression load in counter diagonals was calculated to not exceed the expected tension loads from live load, as such members were not detailed to take any tension load. The bridge now stands as a testament to the original design and perseverance of the people of North Blenheim.
IBC 19-38: Retrofitting the Burlington-Bristol Bridge
Danielle Schroeder, EIT, Jesse Gormley, P.E., ENV SP, and John Prader, Ph.D., P.E., Pennoni, Philadelphia, PA
The Burlington-Bristol Bridge, a moveable (vertical-lift) truss bridge that crosses the Delaware River from Burlington County, NJ, to Bristol Township, PA, is operated by the Burlington County Bridge Commission and was first opened to traffic in 1931. The structure and mechanical equipment have undergone modifications, rehabilitation, and maintenance since opening but are primarily original. However, a complete repainting had not occurred for over 30 years due to the presence of lead-based paint. Cleaning the steel for repainting necessitated a containment system be constructed, including tarps and access rigging, which would significantly increase the surface area of the bridge and thus the applied wind loads. A finite element model of the bridge was used to analyze tarp configurations to account for these loads, the results of which indicated strengthening of the Lift and Tower Spans were necessary. Temporary bracing and permanent retrofit options were explored, and retrofits were selected to minimize future work. Key truss members were identified for strengthening and retrofits were designed, typically in the form of bolted cover plates. The design process included hand calculations followed by iterative finite element modeling for verification, as well as intermittent quality control reviews. Construction was performed as design-build, with individual retrofits being constructed as designs were completed and construction consultation performed throughout. Some project complexities included maintaining traffic throughout construction, as well as maintaining balance of the Lift Span via adjustments to the existing counterweight. Design and construction were completed within a tight one-year schedule from July 2017 to July 2018.
IBC 19-39: Jacques Cartier Bridge – Challenges in Wind Rehabilitation Work of an Old Steel Truss Bridge
Stoyan Stoyanoff, Ph.D., P.Eng., ing., RWDI, Bromont, Quebec Canada; Sylvie Boulanger, ing., P.Eng. Ph.D., JCCBI, Longueuil, Quebec Canada; Steve Zhu, COWI North America, North Vancouver, BC Canada
The Jacques Cartier Bridge is one of the most important bridges in Montreal, Canada. It was opened to traffic in 1930, being ever busier and today about 100,000 vehicles per day are passing over the Saint Lawrence River. Due to its sound design and excellent maintenance, this bridge is in remarkably good structural health today and plans were put forth to extend its life to 150 years. Notwithstanding its good overall condition, the initial survey showed the bridge reduced capacity to resist the code-specified equivalent static wind loads. However, this methodology does not adequately capture the unique wind dynamic properties of this large old steel truss bridge with built-up members, and the initial assessment of the bridge suggested that using the traditional code-based methodology might be overly conservative leading to a costly rehabilitation program. RWDI and COWI were thereafter engaged to conduct studies, including bridge ambient and wind tunnel tests, and evaluation of the refined wind loads and capacities, to optimize the bridge wind rehabilitation. The proposed paper will focus on details of the methodology used and the resulting benefits. The initially code based estimate of reinforcement was reduced by approximately 50%. This study is a good example of an efficient collaboration between the bridge operator, designers and specialized consultants resulting in an optimal rehabilitation program.
IBC 19-40: Multiaxial Fatigue Life Assessment of a Roller-Coaster Support Bracket and a Vertical-Lift Bridge Connection using Strain Rosette Data
Sofia Puerto Tchemodanova and Masoud Sanayei, Tufts University, Medford, MA ; Erin Santini Bell, University of New Hampshire, Durham, NH
Fatigue-induced damage is one of the most common types of damage experienced by civil engineering structures subjected to cyclic loading such as bridges and roller-coasters. Similar techniques for the estimation of remaining fatigue life can be used in both highway bridges and roller-coaster connections because of the similarities of these structures in term of structural and environmental demand as well as maintenance procedures. A framework for the analysis of multiaxial fatigue damage using strain rosettes installed on welded connections is proposed. The applicability of this methodology is shown using strain measurements collected in a roller-coaster bracket and a welded truss connection of a vertical-lift bridge. Commonly used uniaxial fatigue analysis methods are insufficient in complex structures that experience variable amplitude, multiaxial loading, and non-proportional loading. Data sets with these characteristics are used for the estimation of the number of multiaxial stress reversals induced by in service loads and the number of associated cycles using the rain-flow method. Methods proposed for proportional loading and non-proportional loading are compared. Numerical optimization is used for the localization of the critical plane or the most fatigue damaging plane in a data set. Results show that non-proportional loading and the accuracy of the critical plane estimation can cause a significant decrease in the estimates of remaining fatigue life. This new methodology is anticipated to be used for real-time fatigue prognosis aiming to address critical needs related to maintenance procedures, visual inspection techniques and evaluation tools for infrastructure networks.
Design 2 Session
Time: 1:30 – 5:00 PM
Session Chair: Matt Bunner
Room: Woodrow Wilson B/C/D
Our “Design 2” Session has an exciting and diverse collection of presentations on interesting projects from across the country and across the Atlantic. Our eclectic mix includes topics ranging from MASH-compliant barrier gate design for bridges, to historical and research discussions, to various project challenges. Each presents a complex issue that had to be addressed to facilitate the design of various components of both steel and concrete bridge types.
IBC 19-41: Virginia Adjacent Member Connections for Prestressed Concrete Boxbeams and Slabs
Junyi Meng, P.E., Virginia DOT, Richmond, VA
A critical element in the prestressed concrete boxbeams and slabs. The primary functionality of the shear keys is to hold the prestressed concrete members together and transfer the live loads. However, failure or less effectiveness of the shear keys is a nationwide issue. VDOT, working closely with Virginia Tech, developed an innovative connection for prestressed concrete members. The connection is reinforced and filled with Very High Performance Concrete (VHPC). Several bridges have been designed and one bridge was constructed with the connection. Based on the test and field evaluation, the connection performs very well.
IBC 19-42: Replacing a Historic Welded Steel Rigid Frame Bridge
Rebekah Gaudreau, WSP Inc., Eliot, ME ; Adam Stockin, WSP Inc, Manchester, NH ; Joe Adams, New Hampshire DOT, NH
The existing 216’ long, 3-span continuous welded steel frame structure over I-93 was built in 1962. Though this bridge was in good condition due to its high profile standing on the historic bridge register, it needed to be replaced because of the much-needed widening of the interstate. This existing structure won an AISC national bridge award in 1964 and was the first known use of welded steel rigid frames in the on the primary road system. This trendsetting structure reflected the industry move toward using welded connections to replace riveted built up steel sections for longer spans. Due to the historical significance of this bridge, the resource community wanted to ensure that the replacement bridge emulated the aesthetics of the existing structure. The replacement bridge is a 308’ continuous steel frame structure consisting of 2 – 154’ long spans. The bend radius of the central pier frame leg matches the radius of the transitions on the existing structure.
Due to the unique nature of this bridge, a hybrid stiffness/finite element model was produced to analyze stresses in the flanges, web, and stiffeners under gravity loading, and to complete a buckling analysis to determine plate sizes in the pier region. The model was also used to develop force responses in the remaining portion of the bridge for sizing of members and splices. This historic and nationally significant structure was carefully dismantled and stored for future use, while the replacement structure stands as a modern legacy of this innovative structure.
IBC 19-43: Evolution of Bolt and Rivet Shear Strength in Steel Structures
Raymond Tide and Douglas Crampton, Wiss, Janney, Elstner Associates, Inc., Northbrook, IL
The shear strength of connections (bolt or rivet) is dependent upon the material properties of both the connector and the connected gusset plates. Historical theoretical and empirical solutions were developed to address this issue. Based on extensive and available connection test data, a re-evaluation allowed a revision to the empirical procedure, in either allowable stress (ASD) or ultimate strength (LRFD) format, resulting in the elimination of the need for the solution and difficulties associated with the theoretical non-linear simultaneous equation procedure. The historic empirical solution was based on concept of “balanced design,” an ASD concept, that resulted in a significant bolt/rivet shear strength reduction as the overall connection increased in length. The proposed revised procedure uses the “limit states” of strength (ultimate) based on the gusset plate net section area and quasi-stiffness (yield) based on the gusset plate gross section area. A statistical analysis was performed on the applicable existing data, 49 tests, transformed into a non-dimensional format which demonstrated that the shear strength of the bolts/rivets were essentially independent of the connection length. The test samples include numerous grades and types of rivets, and ASTM A307, A325 and A490 bolts and a wide range of gusset plate material including ASTM A7, A36, A440, A572 and A514. The reliability in LRFD format is adaptable to either ASD or LRFD format. The proposed results can be compared to the current design values for bolts/rivets as stated in the relevant AASHTO, AREMA and AISC documents.
IBC 19-44: Advantages of Permanent Top Strands in Precast/Prestressed Concrete Bridge Girders
Richard Pickings, P.E., BridgeSight Inc., South Lake Tahoe, CA ; Richard Brice, Washington State DOT, Olympia, WA
The control of concrete stresses near the ends of precast/prestressed concrete bridge girders is a critical element of flexural design. Large pre-compression forces due to eccentrically placed prestressing strands can cause tension overstress at the top face of the girder. Traditional strategies for controlling girder end stresses are debonding (shielding) of strands near the ends of the girder, harping (draping) of the strands, or less commonly; installation of temporary top straight strands. However, all of the strategies add time and cost to the girder fabrication processes as well as other unique complications. For example: debonding limitations imposed by design specifications are difficult to achieve in heavily prestressed long span girders, strand harping has safety concerns and is avoided by many precast fabricators, and on-site execution of a carefully orchestrated detensioning procedure is required to remove temporary top strands. A less intuitive, but safer and more cost-effective strategy is to install a few permanent fully-bonded pretensioned strands near the top of the girder. These strands act to reduce tension overstresses during initial conditions and can have minimal impact on the final stress conditions. This paper presents design theory and a parametric study showing that this approach can be nearly as effective as traditional stress control measures for common pretensioned I-girder sections used by state departments of transportation.
IBC 19-45: Detailing for Precast Elements Under High Seismicity in the Sound Transit Northgate Link Extension
Justin Clark, P.E. and Yakov Polyakov, P.E., SE, WSP , Seattle, WA
The 2,500-ft long aerial guideway and elevated station within the Sound Transit Northgate Link light rail extension is comprised of multiple cantilever and straddle bents to carry the precast concrete tub girder guideway over a four-lane roadway twice. The high seismicity and geometric constraints of the project area, coupled with the complex details required to frame precast members into the cast-in-place (CIP) elements that must support them, forced the design team to creatively solve these challenges to meet the needs of the project. The five-span, two-level elevated station was designed and detailed to comply with competing code constraints, requiring ductile behavior in the mezzanine and platform beams to comply with the International Building Code (IBC), while also providing adequate ductility in the columns to satisfy AASHTO LRFD Bridge Design requirements. Seismic requirements and soil conditions necessitated deep 8’ to 10’ diameter drilled shafts supporting heavily reinforced guideway columns with large amounts of confinement reinforcement within the plastic hinge zones to facilitate adequate ductility. Utilizing trapezoidal bent caps and girders in alignment with the project architectural requirements created challenges at the connections between the congested columns and the irregularly shaped bent caps and superstructure. Using a combination of dapped end girders supported on bent cap blisters, pipe-pin restrainers to isolate select columns from the connected crossbeams, and providing robust continuity reinforcement in the superstructure at integral piers allow the structure to have adequate capacity protection structural behavior under the design earthquake event.
IBC 19-46: 3D Simulation Testing of Resistance Barrier Gates
Rama Krishnagiri and Steven Esposito, WSP , Lawrenceville, NJ ; Michael Abrahams, WSP , New York, NY; Steven Harlacker, Hardesty & Hanover, New Haven, CT; John Longworth, New Jersey DOT, Trenton, NJ
The WSP team was challenged to design resistance barrier gates for a movable bridge to comply with the 2015 AASHTO Manual for Assessing Safety Hardware (MASH), sustain Test Level -2, improve time of operation, and provide an infinite fatigue life in an aggressive coastal environment with design wind gust speeds of 125 mph. These challenging requirements came late in Final Design due to the release of MASH and the then current AASHTO, further amplified by the client’s need for a more robust fatigue design due to then recent gate failures, after Superstorm Sandy. There was no prior history of successfully meeting these mandates applied to NJ’s movable bridge sites along the coastline that were particularly vulnerable. Our paper will discuss site-specific challenges in designing a gate not only robust enough to meet the infinite life fatigue design, but also flexible enough to sustain the mandated vehicular impacts, ride-down acceleration, and limit Occupant Impact Velocity. While this type of change is typically a multi-year undertaking, the close collaboration with a gate manufacturer and a research facility to develop a prototype for a Finite Element simulation analysis helped in completing efforts within a short period to verify all aspects of performance. Simulation included sophisticated modelling of the gate, anchorages, cables and members. Test Level 2 simulations included a small vehicle (passenger car) and a heavy vehicle (pickup truck). Actual crash tests were also performed on the gates identical to the simulated model and the results were in excellent agreement with the simulation.
IBC 19-47: Reduced Partial Factors for Load Assessment in UK Assessment Standards
Chris Hendy, FREng, MA CEng FICE Eur Ing, Atkins SNC-Lavalin, Epsom, United Kingdom
Design standards are based upon a range of input variables for resistance, action and modelling. The distribution type and parameters for each determine the partial factors appropriate to achieve a defined reliability level over a specified reference period. For assessment a reduced reliability level may be accepted due to the greater cost of providing reliability through strengthening when com-pared to the cost of providing it at design. This would allow the use of lower partial factors, bounded by the need to provide a minimum acceptable reliability level for human safety. Adoption of this approach for assessment would have significant benefits for an ageing UK infrastructure by reducing the need to carry out costly strengthening and retrofitting schemes whilst still ensuring appropriate structural reliability levels are maintained. This paper presents a study investigating appropriate reduced partial factors to be applied through UK assessment standards, the sensitivity of these values to input distribution model assumptions, and how they could be implemented across industry. It concludes with case studies implementing the approach on real bridges in the UK which demonstrated that strengthening could be avoided with this reliability-based approach which would have been required were design partial factors used.
June 11, 2019
Please join us for a tour of the Arlington Memorial Bridge! The 2019 IBC tour will give attendees the opportunity to preview the Arlington Memorial Bridge Rehabilitation project, a National Park Service project being administered by Federal Highway Administration.
The tour will consist of a considerable amount of walking on an active construction site so, please be prepared to walk. The tour will kick off with a brief project introduction and overview, which will be presented by the Kiewit Construction team and Federal Highway Administration in the Kiewit Field Office. We will then begin the guided walking tour on the Arlington Memorial Bridge.
To learn about the Arlington Memorial Bridge Rehabilitation, please click here.
SAFETY FIRST! To participate in this construction site tour, there are a few things that will be required.
- Sleeves (long or short). Tank tops are not permitted.
- Hard Hat
- Safety Glasses
- Type 2 or 3 Vest
A limited supply of PPE will be available upon request.
Additionally, all participants will be required to sign a separate release form.
* The bus will depart The Gaylord National Resort and Convention Center at 1:00 PM, arriving to the project site at 1:30 PM. The bus will depart the project site at 4:30 PM and arrive back at The Gaylord National Resort and Convention Center at 5:00 PM. *All timing is subject to change
The tour is limited so be sure to reserve your spot today (on the registration page)!
W-6: BrIM Applications Beyond Design Engineering
Time: 1:30 – 3:30 PM
This objective of the workshop would be to provide a greater understanding of FINLEY’s use of BrIM touching on aspects from each of the submissions we submitted previously (with both steel and concrete case studies). Further, this workshop will provide attendees with a comprehensive overview of a successful implementation of Bridge Integration Modeling (BrIM). It will further the understanding as to how FINLEY utilizes BrIM in the planning, design, and construction process. Additionally, it will demonstrate the great benefits that FINLEY has gained through this approach.
Speakers: Ivan Liu and Jerry Pfuntner, FINLEY Engineering Group, Tallahassee, FL
W-7: Experiences in the Performance of Bridge Bearings and Expansion Joints Used for Highway Bridges
Time: 1:30 – 3:30 PM
Domestic Scan 17-03, Experiences in the Performance of Bridge Bearings and Expansion Joints Used for Highway Bridges was initiated to facilitate the exchange of recent ideas and best practices for Bridge Bearings and Expansion Joints, and included design, performance evaluation, maintenance and repair/reconstruction. Discussions involved staff from design, construction, maintenance and operations of state and other transportation agencies. Details for various bridge types (i.e. materials, span arrangements, geometry) and sizes were examined. The workshop offers lessons learned from experiences by the various participating agencies and provides guidelines for design and details, construction specifications and maintenance procedures for durable bearings and expansion joints.
Speaker: Bijan Khaleghi, Washington State DOT, Olympia, WA
W-8: Grouting of Post Tensioned Bridges, A Historical Perspective
Time: 4:00 – 6:00 PM
The Workshop is intended to provide a comprehensive presentation of the development of grouting methods currently used to protect Post Tensioning systems in Concrete Bridges. Information on best practices, technical resources available to designers, design advantages of bonded, cementitious grout, review of the performance of the system, lessons learned and project experiences will be presented. Attendees will obtain a better understanding of the technology and how it can be successfully used in future projects.
Speakers: Dr. Randy Poston, Pivot Engineers; Miroslav F. Vejvoda, Post Tensioning Institute (PTI); Gregg A. Freeby, ASBI; Andy Mish, Modjeski and Masters
W-9: Innovation in Design and Construction Challenges of Jointless Bridges in Seismic Regions – From Research to Implementation
Time: 4:00 – 6:00 PM
Jointless bridges are constructed to work integrally with intermediate piers and abutments. Movements due to creep, shrinkage and temperature changes are accommodated by using flexible Bearings or foundation and through incorporating relief joints at the ends of the approach slabs. Advantages of jointless bridges include reduced maintenance costs, improved structural integrity, reliability and redundancy, improved long-term serviceability, improved riding surface, and reduced initial cost. In recent times, jointless bridges have been built in seismically sensitive areas. This workshop provides the state-of-practice from in research, implementation, design, construction practices, seismic resiliency, and detailing of jointless bridges.
Speakers: Dr. Phil Yen, International Association of Bridge Earthquake Engineering (IABEE); Bijan Khaleghi, Washington State DOT, Olympia, WA