Thursday, October 22, 2020
Time: 1:30 – 4:00 PM
IBC 20-31: Float-Out and Float-In of BNSF Wind River Truss
Joe Knapp, Genesis Structures, Kansas City, MO; Kyle Izatt, Advanced American Construction, Portland, OR
The Burlington Northern Santa-Fe (BNSF) Railroad Bridge No. 58-8, is located along the Northern bank of the Columbia River Gorge between Portland and Hood Mountain Oregon. As part of BNSF’s continued rail improvements throughout the Pacific Northwest, the circa 1900’s 200 ft thru pin style truss bridge over the conflux of the Wind River was replaced with a new 260ft ballasted thru truss bridge. This presentation will focus on the 12-hr float-out/float-in period of a 32-hr track closure. Construction methods used for the execution of the main span change out will be discussed, including the erection of the new truss off-site, marine transportation upriver and through a navigational lock and dam, development of the floating systems for the float-out and float-in, the design of the strand jack lifting towers used as part of the float-in, the design of a unique ballasting system for the float-out and the demolition of the existing truss. The presentation will also highlight the coordination required between multiple entities including the owner, engineer of record, other prime contractors on the project, the U.S. Army Corp of Engineers and Bonneville Power Administration.
IBC 20-32: Accelerated Replacement of the CSX Bayou Sara Swing Span Bridge
Kevin Kane, P.E., Brasfield & Gorrie, LLC, Birmingham, AL; David Knickerbocker, Ph.D., P.E., HDR, Newark, NJ
CSX’s single-track, 163-ft long Bayou Sara Bridge swing span was fast approaching 100 years of age and in need of replacement. Approach spans had been recently replaced, and foundation integrity was determined to be adequate to support a replacement span. Objectives for the replacement included minimized maintenance, remote operation capability, and a premium on speed of replacement, to minimize service interruption. The resulting span is a hydraulically-driven through-girder span with service tower elevated over the railway at the center pivot. The rail service outage duration for the replacement of the bridge was significantly reduced at the request of CSX. Several key factors allowed for accelerated construction. This included strategic preparations and select demo made to the existing bridge prior to the replacement, and the accelerated design and fabrication of a structural steel frame (grillage) to facilitate immediate load transfer from the bridge to the substructure. The grillage was suspended beneath the superstructure with the pivot bearing, center wedges, and rack all pre- installed on it for float-in. The grillage and preparations made to the existing bridge made it possible to replace the swing span with a rail service outage of only 14 hours.
IBC 20-33: Rail-Structure Interaction and Track Serviceability Analysis of High Speed Rail Bridges
Sarwar Naveed, P.E., S.E., RailPros, Irvine, CA
Performance of structural expansion joints and limiting of the rail stresses on high speed rail bridges to avoid rail fracture, limiting the stresses on the fasteners, vertical/transverse deflection of the structure, deck twisting and limiting the rotations at joints are utmost important features for the design of high speed rail bridges in addition to regular bridge design practice. This analysis requires three dimensional geometrical modelling, capturing the stiffness contribution from superstructure, columns, bearings, abutments, shear keys, pile supports, non-linear behavior of rails fasteners, soil structure interaction and contribution of rails beyond the bridge limits. The analysis considers lower and upper bounds of both mass and stiffness using modal damping and non-linear time history analysis for complex structures. A case study is presented on one of the California High Speed Rail Bridges that will support trains running at design speed of 250 miles/hr. This is a three span post- tensioned U girder superstructure, columns and abutments are supported on drilled shafts type foundations. A three dimensional model of the bridge including substructure, rails and boundary elements were modeled using multi-step train dynamic loading and non-linear seismic time history analysis to evaluate the behavior of bridge deck vibration, opening and closing of structural expansion joints, bearing rotations, axial stresses in the continuous welded rails, bi-linear behavior of the rails fasteners. Non-linear time history considers 7 ground motions.
IBC 20-34: Withdrawn
IBC 20-35: Two Become One: Advanced Analysis and Design for Adjacent Precast Tub Girders for High Speed Rail
Chris Knipp, P.E., and Yong Yang, P.E., S.E., Jacobs, Chicago, IL
The estimated $117.4 billion California High Speed Rail Program is working towards a dedicated passenger route from L.A. to San Francisco, reducing travel times from 11 hours to 3 hours. The ballasted bridge at Kings River is composed of 2-two span units with a max span length of 112’ and a total length of 445’, and is to carry two lines of high speed rail. The superstructure is supported by two column bents, on CIDH piles in liquefiable soil with a high probability of significant scour. The design of the superstructure incorporated a unique concept of erecting two precast prestressed concrete tub girders, placed together and connected through their individual interior webs, to form a single span two-cell box girder segment. Post-tension tendons were used near mid-span and over the bents to meet allowable stress and strength requirements. Pre-cast deck panels were placed to act as stay in place formwork for the cast-in-place deck to form a composite superstructure. In addition, advanced analyses were required per project specific design criteria. Deck deformations, rail deformations, and rail stresses were computed for OBE, thermal, wind, and Cooper E-50 loading. The focus of the presentation will be on the unique analysis and design aspects of this bridge including design of CIDH foundations in liquefiable soils, the design of a multi-element multi-cell composite pre-stressed and post-tensioned concrete tub girder, advanced analyses for structural deformations, rail stresses and deformations, and dynamic structural response for high speed rail loading.
Rehabilitation, Part 2
Time: 1:30 – 5:00 PM
IBC 20-46: Diagnosis and Repair of Deficiencies in Ohio Post-Tensioned Bridges
Travis Butz, P.E., and Mike Kronander, P.E., Burgess and Niple, Columbus, OH; Dallas Montgomery, P.E., Burgess and Niple, Louisville, KY
Beneath the surface of otherwise visibly sound post-tensioned bridges lies potentially significant corrosion and deterioration that, if left untreated, can lead to shortened service life and reduced load carrying capacity. Tendon corrosion is more common in bridges built prior to 2003 due to the grouting materials and construction procedures that were used at that time. If identified early, measures can be taken to arrest corrosion and protect tendons from further deterioration.
Recognizing the potential for deficient conditions, the Ohio Department of Transportation retained Burgess & Niple to inspect and perform non-destructive testing (NDT) for ten post-tensioned bridges. An initial review of construction documents was conducted for each bridge, including design drawings, grouting logs, and other records. This was followed by a physical assessment, including an arms-length visual survey of all post-tensioned members. An NDT program was then developed for internal and external tendons using a risk-based protocol. The NDT consisted of in-situ testing procedures to assess the condition of the tendons without damaging the strands. Assessment methods included visual inspection using a borescope, corrosion rate testing of strands and sampling and testing of the grout.
After completion of the inspection and NDT, repair plans were prepared for four bridges: two box girder structures with voids identified in the tendons, and two post-tensioned pier caps where corrosion was present at the anchorages. Repairs included remedial grouting, removal and replacement of anchorage pourbacks, and installation of a corrosion resistant impregnation system.
IBC 20-47: In-depth Inspection, Refined Analysis and Retrofit of Two Skewed Steel Bridges with Distortion-Induced Fatigue Cracking
Jordan Coleman, EIT, Alexander Kluka, and Rama Krishnagiri, P.E., WSP USA, Lawrenceville, NJ; Michael Abrahams, P.E., WSP USA, New York, NY
A common issue in composite steel girder skewed bridges is cracking that can occur due to fatigue in intermediate diaphragm connections.
This paper describes the inspection findings, in-depth finite element analysis and retrofit of a pair of single-span composite girder bridges with significant web/weld cracking. The structures, built in 1967, are highly skewed with staggered intermediate diaphragms. The diaphragms are partial depth, channel sections that are bolted to the stiffeners which are welded to the girder web. An in-depth inspection documented over fifty cracks, originating at the diaphragm connection plate lower weld terminus and extending to the web base metal. The rocker bearings were over extended. The cracking was believed to be associated with distortion induced fatigue, so a highly fine-meshed 3D model of the structure was created to evaluate fatigue. The evaluation followed FHWA-NHI-16-016 document, Design and Evaluation of Steel Bridges for Fatigue and Fracture. The analyses indicated significant torsion in the system due to the skew. This was exacerbated due to restrained transverse movements by the rockers, differential live load deflections and the staggered diaphragms, causing significant stress risers at the weld termini of the diaphragm plates. The analyses validated the observed web/weld cracking. Several retrofit options were considered, and it was concluded that full removal of the intermediate diaphragms was the most cost effective solution. The basis of this solution was that the only purpose of the diaphragms was to assist in the erection of the structure and they served no purpose once the deck was cured.
IBC 20-48: Withdrawn
IBC 20-49: Deck Slab Closure Effects on Bridge Behavior: James River Bridge Case
Sherif Daghash, Ph.D., P.E., Daniel Dowling, and Deanna Nevling, Michael Baker International, Virginia Beach, VA
This paper investigates the James River Bridge (JRB) to determine how many consecutive open bridge deck joints can be eliminated as part of an asset management plan covering the maintenance and rehabilitation of the bridge over the next 30 years. The paper presents the next phase of work as a follow-up to a previous paper (IBC16-07). The JRB, owned and maintained by Virginia DOT, consists of 302 prestressed concrete multi-beam spans and one steel through-truss lift span with a total length of 4.4 miles. The maintenance plan is comprised of both restorative maintenance, to repair deterioration in bridge elements, and preventative maintenance to preserve the bridge and slow future deterioration. To study the effect of bridge joint elimination on bridge behavior, a three-dimensional finite element model (FEM) was created of four consecutive monolithic prestressed concrete superstructure spans using MIDAS® Civil. One, two, or three consecutive joints were eliminated, using link slabs, in the model to form 2-, 3-, or 4-span units. Link slabs are poured over interior supports to create a continuous bridge deck. Link slabs minimize bridge maintenance and extend the life of existing structure by stopping water leakage through deteriorated joints. However, constructing a continuous deck over an interior support results in additional lateral loads acting on the existing substructure. Force effects on the structure due to uniform temperature and braking loads in combination with the link slabs were analyzed. A summary of the FEM approach, a comparison of the analysis results, and joint elimination recommendations are presented.
IBC 20-50: Structural Testing and Monitoring of the I-15 Virgin River Bridges
Travis Butz, Edward Cinadr, and Mark Bernhardt, Burgess and Niple, Columbus, OH; Jesse Sipple, Bridge Diagnostics, Inc., Louisville, CO
Four steel bridges located on a remote stretch of Interstate 15 in northern Arizona are currently the subject of a study involving visual inspection, load testing, long term instrumentation and remote health monitoring. The project is being funded by the Arizona Department of Transportation (ADOT) through a FHWA Accelerated Innovation Deployment Grant. The purpose of the project is to utilize state-of-the-art structure health monitoring technologies to provide information that will ensure the safety of the traveling public and provide better information to assist ADOT in short and long-term decision making about these significant bridges. The steel bridges currently exhibit widespread fatigue cracking. The presentation will provide a status update on the project which began in 2016 and continues through 2020. The discussion will include a history of the bridges, visual inspection efforts and documentation, analytical modeling work, load testing and instrumentation, instrumentation selection, fatigue analysis, site challenges, and long term monitoring strategies, including development of the monitoring website. The website allows elements of the bridge to be monitored remotely by ADOT in real time. The functionality of the website can be can be demonstrated live as part of the presentation.
IBC 20-51: Steel Truss Gusset Load Rating
David Konz, P.E., S.E., and Mark Shlyakov, P.E., Atkins, Tampa, FL
Following the I-35W collapse in Minnesota, Gusset-Plate load rating procedures were overhauled by FHWA and subsequently adopted within AASHTO Manual for Bridge Evaluation (MBE). This presentation will review the major milestones in the development and application of the 2014 MBE (Article 6A.184.108.40.206 – 6.10) and 2018 3rd Ed. MBE. Examples will be centered around six unique historic structures in northeast Florida.
- Thru-Arch: Myrtle Avenue, 1955. 3-Rib steel arch (Max span = 385.5’)
- Swing Bridge: St. Mary’s River Bridge, 1927. 4-Span steel truss (Max span = 101’)
- Cantilever Truss: Mathews Bridge, 1953. 6-Span steel (Max Span = 810’)
- Moveable Lift Bridge: Main Street Bridge, 1941. 3-Span steel truss (Max span = 386’)
- Tied Arch: Isaiah D. Hart Bridge, 1967. 3-Span steel truss (Max span = 1088’)
- Suspension Bridge: Hal W. Adams Bridge, 1947. 3-Span steel truss (Max span = 420’)
This steel truss Load Rating assignment includes systematic evaluation of gusset plates on each of the historic truss bridges in accordance with current MBE procedures. For each bridge, a 3-D model was developed for loads and was used with field measurements of deterioration from inspection reports to create an as-inspected rating. Rehabilitation effects were also incorporated into the ratings. Posting avoidance was implemented for truss panel location with low load ratings. The avoidance measures centered around detailed Finite Element Analysis (FEA) and advanced deterioration evaluations to refine the behavior of the gusset plates, resulting in cost-savings for DOTs that are implementing these new AASHTO requirements.
IBC 20-52: Adding a Lane to the Historic Pulaski Skyway – Design and Construction of Large Floorbeam Cantilevers
Daniel Zaleski, P.E., and Michael McDonagh, P.E., P.Eng., WSP USA, Lawrenceville, NJ; David Hawes, New Jersey DOT, Trenton, NJ
The Pulaski Skyway is a critical link between northern New Jersey and New York City. The historic 1932 landmark is in the midst of a multiphase rehabilitation that intends to bring the structure to a state of good repair with minimal required maintenance over the next seventy-five years, while also improving its operational functionality to support the large amount of traffic it receives daily. The purpose of this paper is to illustrate the design, detailing and construction challenges of expanding the width of part of the structure to support an additional lane. This new acceleration lane from the structure’s center ramp required extending over sixty existing floor beam cantilever sections from a four-foot overhang to as much as a nineteen-foot overhang. The successful construction of the floor beam extensions involved close cooperation with the contractor, client and the client’s resident engineer to accommodate known field conditions as well as unexpected field conditions. The paper will discuss the design and detailing process used to extend the existing floor beams, the field inspections needed to confirm the information on the original shop drawings, and the final construction of the extensions.
W10: Long-term Bridge Performance Research through Accelerated Structural Testing
Franklin Moon, Ph.D., Rutgers University, Piscataway, NJ
Time: 3:00 – 4:30 PM
The aim of this proposed session is to introduce conference participants to a new form of accelerated structural testing to examine the long-term performance of various bridge systems. This research is enabled by the BEAST (Bridge Evaluation and Accelerated Structural Testing) Lab that is being operated as a shared-use facility by the Center for Advanced Infrastructure and Transportation (CAIT) at Rutgers University. This facility is the first to permit researchers to apply controlled live loads, environmental loads, and de-icing agents to full-scale superstructure systems in an accelerated manner, with the goals of:
- Providing objective and quantitative data related to the durability of various bridge elements, details, coatings, etc. to inform current design practices
- Developing accurate performance forecasting tools to underpin modern asset management strategies aimed at reducing life-cycle costs while maintaining safety and functionality
- Providing near-term feedback on the performance of innovative designs and materials to drive both developmental activities and adoption into practice
The proposed session will be organized to both highlight the diversity of research efforts currently ongoing as well as to highlight the shared-use vision for this facility, where research from many different states and universities may participate in conducting research within this facility. Six presentations are planned that will provide: 1) Overview of accelerated testing and the specific capabilities of the BEAST, 2) Relevance of accelerated testing for FHWA Long-Term Infrastructure Performance Program, 3) Quantitative tracking of deck deterioration via multi-modal NDE, 4) Understanding concrete deterioration mechanisms through accelerated structural testing, 5) enabling of next-generation SHM through accelerated testing, and 6) Quantifying shear stud fatigue loading via accelerated structural testing.
W15: Get Your A-GaME On! – Enhanced Geotechnical Site Characterization for Foundation Design and Constructability
Benjamin Rivers, Federal Highway Administration, Atlanta, GA
Time: 2:30 – 5:00 PM
The quality and scope of geotechnical site characterization influence the decisions on foundation selection, design, constructability and performance, and impact project risks to schedule and budget. This workshop introduces effective, underutilized geotechnical exploration methods, and relates reliability of design and construction to explainable site variability and the removal of geotechnical uncertainties. It is time to bring geotechnical site characterization for your bridge projects into the 21st Century. It’s time to bring your A-GaME!