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Innovations in Bridge Engineering Technology Edited by Khaled M. Mahmoud | PDF Free Download.
In the last few years, remarkable technological advances have been achieved in bridge engineering technology.
These cover a wide spectrum of issues, ranging from design, maintenance, and rehabilitation methodologies to material and monitoring innovations.
Within an international framework of exchanging the state-of-the-art in the field of bridge engineering, the Fourth New York City Bridge Conference was held on August 27–28, 2007. This book contains a selected number of papers that were presented at the conference.
These papers are valuable contributions to the body of knowledge in bridge engineering technology.
The Fourth New York City Bridge Conference was distinguished for its global impact. Bridge engineering experts presented papers from Belgium, Canada, Croatia, England, France, Germany, Italy, Japan, Lebanon, Northern Ireland, Scotland, Switzerland, Taiwan and Turkey.
These, along with a list of prominent bridge engineering professionals from the United States, will assure the archival quality of this book.
The proceedings lead off with a paper by Forde and Ohtsu on the “International state of practice in the inspection of grouted duct post-tensioned concrete bridge beams and decks”. Post-tensioned concrete bridges have been used for both rail and road bridges for some forty years. Problems were first noticed with road bridges due to the use of de-icing salts.
However, there have been collapses of post-tensioned concrete railway bridges. Following these series of collapses, the Highways Agency in the United Kingdom enforced a ban on the construction of post-tensioned bridges with metallic tendon ducts.
The moratorium was lifted with the introduction of plastic tendon ducts. The paper focuses on the analysis of impact-echo NDT of concrete beams with plastic tendon ducts – using both a conventional frequency domain analysis and using the Japanese SIBIE (Stack Imaging of Spectral Amplitudes Based on Impact-Echo) method.
The authors show that the SIBIE method of analysis exhibits great promise in testing these previously difficult to inspect plastic tendon ducts, using impact-echo. Segmental bridges are commonly used in the last thirty years as part of modern roads and highways in Croatia.
During regular and preventive bridge inspections some defects were detected. In “Durability of concrete segmental bridges” Banic et al present typical types of concrete segmental bridges built in Croatia, types of construction and condition state of several types of segmental bridges.
Condition of those structures was determined during bridge inspections conducted in the last five years. Characteristic damages of segmental bridges, rehabilitation procedures applied in several cases and also some improvements on new structures are presented.
In “Cyclic tests of precast segmental unbonded post-tensioned concrete bridge piers”, Ou et al present an experimental study on the seismic performance of precast segmental unbonded post-tensioned concrete bridge piers.
The pier specimen consists of a foundation, four hollow column segments and 5.7-meter high pier cap. The prestressing tendons are located inside the hollow core of the pier column and hence are unbonded with the surrounding concrete.
In the first pier specimen, no mild steel reinforcement is extended across the column segment joints.
In the other two specimens, longitudinal mild steel bars, also referred to as energy dissipation bars or ED bars, anchored at the foundation and extended up to the pier cap, are added to enhance the seismic energy dissipation.
The test results showed that all the pier specimens exhibited satisfactory ductile behavior. The hysteretic energy dissipation, lateral strength and residual drift upon unloading of the specimens increased with the increase of the amount of ED bars.
The Jamestown-Verrazzano Bridge over Narragansett Bay, Rhode Island, USA, features a 1,509 meter-long prestressed segmental box girder main bridge with 23 spans varying in length from 33 meter to 194 meter, and a 732 meter-long trestle structure.
The bridge was open to traffic in 1992 and a baseline inspection was conducted in 1999. The scope of the baseline inspection included analysis, load rating, and comparison of creep deflections based upon as-built shop drawings, and casting and stressing schedules versus field-surveyed conditions.
During subsequent inspections nondestructive and destructive methods were used to investigate the post-tensioning ducts for the presence of voids.
Over 28,000 meters of nondestructive impact-echo (sonic/ultrasonic) measurements were taken on the concrete top slab, webs and bottom slab containing the tendons to evaluate the grouted tendon ducts for voids.
Of the approximately 1,520 tendon ducts tested, 7.5% or 114 tendon ducts were determined to have voids. Void lengths ranged from 0.3 meter to over 94 meters. In most cases the tendons were grout covered but some of the tendons were exposed and exhibited corrosion.
At the time of construction, grouting methods were not always fully effective. Currently, voids in post-tensioned ducts are an issue for a number of bridge owners.
Other repairs include use of epoxy-injection with CFRP reinforcement system for the cracked webs of the segmental box girder pier tables.
In their paper “Inspection and rehabilitation of Jamestown-Verrazzano segmental concrete bridge”, Abrahams et al discuss these findings and repairs that are currently underway.
Cable-supported bridges are notable for their aesthetic appeal and ability to link long spans. Many of the issues associated with these structures require thorough studies prior to construction.
In “Ultimate capacity of suspension bridges with arbitrary imperfect towers”, Inoue investigates the difference of ultimate capacity of suspension bridge due to the imperfection of towers.
The measurements of tower deviations from the ideal position for constructed suspension bridges, mainly in Japan, have been studied and the tendencies of imperfection have been classified into different types.
The effect of tower imperfection for the ultimate capacity has been investigated by 1-1/2 order analyses using 2-D bridge model. Four types of imperfect tower with the different imperfect shapes were modeled at the freestanding position.
Finally, the difference of ultimate capacity among the imperfect models is summarized and some remarks are offered for more reliable and economical bridge in the future. The new trend in design of footbridges in Turkey is to utilize cables.
Some of these bridges have fake cables while others partially rely on the cable system. These steel composite bridges typically constructed over highways span about 40 to 60 meters.
It was observed that the bridges with fake cables can be substantially heavier than the ones with functional cables.
In “Cable supported footbridge analysis with construction staging”, Caner studies the importance of tensioning sequence of cables and impact of construction staging on the design forces at superstructure to have economical designs.
A case study is illustrated as an example design. Locked coil cable assemblies are used in cable supported road bridges (e.g. as suspenders in suspension bridges and hangers in arch bridges) and a large variety of pedestrian and cycle bridges.
Despite of lots of installations all over the world and recent product enhancements, locked coil cable assemblies are not so well known in the USA. Recently, increased demand for the product has been observed.
In “Locked coil cable assemblies for bridges”, Bechtold et al introduce an overview about present and past applications of locked coil cables.
Isolation bearings have become a standard tool for engineers designing bridges in seismic regions. However, the added complication of cold weather has raised concerns with rubber isolators and their performance in northern regions of the United States.
As a result, bridge designers are migrating towards sliding isolation bearings (SIB) in these regions. SIB have been proven to be cost effective and high damping devices on numerous projects to date.
Watson describes the research that led to the development of SIB. In addition several case histories will be reviewed in an effort to demonstrate SIB capabilities in low temperature environments.
Deformations on the order of 11 mm in the masonry plates of installed lead rubber isolation bearings were observed in a highway bridge. Of the more than 400 isolators in the project, approximately 30 showed deformations greater than 2 mm.
Due to the cost, accessibility issues and traffic impacts of removing and replacing the isolators, the Owner agreed to accept laboratory testing as a means to determine which effects, if any, the deformation had on the properties of the lead core isolation bearings.
Jacak and Pezzotti present the “Results of tests performed on lead-rubber seismic isolators with deformed masonry plates”. New bearings were manufactured in accordance with the original project requirements.
The new bearings were first tested to establish baseline properties and validate their compliance with the contract documents. Subsequently, the isolators were deformed in the lab to achieve a similar deformation as that observed in the structure.
The bearings were then tested in the deformed condition and the results compared to the baseline properties. Soil-Structure interaction may play a major role in the seismic response of a bridge structure.
Specifically, a significant reduction in soil stiffness and strength may result in permanent displacement of the abutments and foundations, thus imposing important kinematic conditions to bridge structure.
In “Humboldt Bay Middle Channel Bridge: 3D bridgefoundations-ground system”, Trombetti et al show the effects of this behavior referring to the Humboldt Bay Middle Channel Bridge, in California, USA.
The Finite Element model and nonlinear solution strategy are built in the open-source software plat-form OpenSees. The 3D nature of bridge response imposes significant computational challenges.
The soil is modeled as a nonlinear material with a Von Mises multi-surface kinematic plasticity model so as to reproduce elasto-plastic shear response.
The results obtained using 1978 Tabas earthquake record show that changes in properties of the superficial soil layers dictate significantly different time histories of dynamic excitation at the various support points of the bridge (piers and abutments).
Bridge design methodologies have made significant strides due to technological advances in construction, fabrication and testing techniques.
The $210 million Florida Avenue Bridge project is being designed to provide reliable access between St.
Bernard and Orleans parishes over the Inner Harbor Navigational Canal (IHNC) in New Orleans, Louisiana.
The project includes a five-span high-level bridge over the IHNC with a 143-meter center span. Bridge type studies were completed to determine the most viable structure type.
Both cast-in-place segmental concrete box girder and steel plate girder alternates were selected for final design.
In “Design of Florida Avenue Bridge over the Inner Harbor Canal”, Nelson presents the design of the segmental concrete alternate.
The superstructure consists of a variable depth twin-cell box girder that is supported by voided box column piers and steel HP piles.
The bridge will be built with form travelers using the balanced cantilever method of construction. Heat curving is widely used for fabricating curved steel bridge I-girders. Curving is accomplished by asymmetric heating of the flanges of the straight girder.
Heat is applied along the girder length continuously or intermittently with the heated width varying from 1 /12 to 1 /4 of the flange width depending on the curvature. Curvature develops after the girder cools to ambient conditions.
Current practice limits the maximum temperature to 620o C for conventional Grades 250 and 345 steels. The “Guide for Highway Bridge Fabrication with HPS 485W Steel” recommends investigating heat curving of HPS 485W at 705o C.
In their paper “Heat curving HPS 485W bridge I-girders”, Gergess and Sen evaluate the validity of the 705o C temperature using non-linear finite element analysis. Other fabrication issues relating to heat curving stiffened and hybrid girders are also addressed.
Results show that the maximum temperature can be somewhat lower. Stiffeners may reduce the curvature by up to 10% while hybrid girders with top and bottom flanges made of different steel grades require different heating profiles.
In “Testing of a novel flexible concrete arch system”, Taylor et al describe the testing of a flexible masonry concrete arch system which requires no centering in the construction phase or steel reinforcement in the longterm.
The arch is constructed from a ‘flat pack’ system by use of a polymer reinforcement for supporting the self-weight of the concrete voussoirs and behaves as a masonry arch once in the arch form.
The paper outlines the construction of a prototype arch and load testing of the backfilled arch ring. Some comparisons to the results from analysis software have been made.
The arch had a load carrying capacity far in excess of the current British Highways Agency design wheel loads. The Great River Bridge, built in 1939, is located in downtown Westfield, a City in Western Massachusetts, USA.
The through truss bridge is a landmark for the City, forming perhaps the most distinctive structure in the downtown area. The project scope was initially limited to the rehabilitation of the 112 meter long, two-span structure.
However the project has grown to include the design of two other bridge structures, four landscaped parks, several thousand feet of urban roadway, and two miles of railroad track.
In “Westfield Great River Bridge”, Ennis presents the different components of the project. The State Route 62 Bridge over Crooked Fork Creek in Morgan County, Tennessee, USA, was originally designed in 1940.
After more than six decades of service to the citizens of this rural community, the bridge had become structurally deficient and functionally obsolete.
The Tennessee Department of Transportation (TDOT) decided an extensive rehabilitation was needed to address the structural problems and improve its functionality.
The project entailed a complete replacement of the original superstructure as well as repair and modification of the existing substructure units.
In “Renewing the Crooked Fork Creek Bridge”, Wilson describes the project which was accomplished without construction within the channel of the creek.
To avoid the need for a lengthy detour, construction activities were phased and traffic control designed so that one lane of traffic could be maintained across the bridge throughout the duration of the project.
The aging highway bridge continuously renewed while accommodating traffic flow. The traveling public demands that this rehabilitation and replacement to be done more quickly to reduce congestion and improve safety.
Conventional bridge reconstruction is typically on the critical path because of the sequential, labor-intensive processes of completing the foundation, the substructure, the superstructure infrastructure in the United States is being subjected to increasing traffic volumes and must be components, railings, and other accessories.
Bridge systems can allow components to be fabricated off site and moved into place quickly while maintaining traffic flow.
Depending on the specific site conditions, the use of prefabricated bridge systems can minimize traffic disruption, improve work-zone safety, minimize impact to the environment, improve constructability, increase quality, and lower life-cycle costs.
In “Rapid delivery! New Jersey overnights bridge rehabilitation for Trenton Bridges” Capers and Cheng discuss the adopted approach to the replacement of the superstructures of two structurally deficient bridges carrying a freeway section of Route US 1 through the capitol city of Trenton, New Jersey, USA.
The Route 70 over Manasquan River Bridge replacement project utilized an innovative precast substructure solution on a project requiring difficult coordination of highway and marine traffic, environmental constraints and community involvement.
The 7.6-meter high, 220.7-meter long bridge, which is supported on five architecturally treated precast High Performance Concrete (HPC) in-water piers, crosses a navigable waterway in the coastal region of the State of New Jersey, USA.
The precast pier column and cap components were fabricated offsite, delivered via barges and trucks and assembled using post-tensioning.
Pier foundations were constructed at the waterline within precast concrete cofferdam shells, which provided pile driving templates, served as architecturally treated formwork for the footings and eliminated construction of traditional cofferdams.
Yermack presents the details of the project in his paper “Accelerated construction of precast concrete piers on the Route 70 over Manasquan River Bridge replacement project”.
Stainless steel reinforcing has been used in numerous structures throughout North America.
Recent advances in concrete technology have provided structural designers with materials which can easily last over 100 years, and the life of many concrete structures today is limited by the reinforcing.
Improvements in the life of the reinforcing can be translated directly into extended life of the structure. Current projections by several transportation agencies show that the use of solid stainless steel reinforcing bar in bridge decks will more than double the life of the bridge deck.
While solid stainless steel reinforcing bar can increase the cost of the bridge deck by as much as 12% (compared to carbon steel reinforcing), the economic value of the longer life outweighs the initial higher cost.
In “Improving tomorrow’s infrastructure: extending the life of concrete structures with solid stainless steel reinforcing bar”, Schnell and Bergmann discuss corrosion resistance and cost saving offered by the use of stainless reinforcing.
The paper “Use of structural health monitoring techniques for a forensic study of bridge accidents”, by Yun, presents an overview of a real-time web-based continuous monitoring system for the Vincent Thomas Bridge.
An effective multi-thread bridge monitoring system architecture is shown. Using the bridge monitoring system, the bridge response to earthquakes, bridge-ship collision and ambient vibration was measured, and the bridge modal frequencies were successfully determined with vibration-based identification methods.
In “Bridge Management and Inspection System for Montgomery County, Maryland”, Shaffer and Schellhase cover an overview of the county’s needs and the solutions that have been developed to significantly improve both the inspection and management processes.
Electronic forms were created to meet the county’s requirements, the most rigorous in the state of Maryland, USA, and thus allowing for entry of all information from the inspection.
Inspection of bridge decks generally relies on visual inspection and use of basic non-destructive testing techniques. Assessment typically involves comparison of observed condition with pre-defined condition states.
Current condition states require little quantitative data and must apply across many different material types and bridge elements. Use of these types of subjective techniques may lead to uncertain assessment of structure condition.
This is particularly true when comparing different structures or structures assessed by different personnel.
One improvement that may be considered to reduce the uncertainty or subjectivity of the current process is the introduction of quantitative measures within the condition states.
In “Objective condition states for concrete bridge deck assessment”, Knight discusses condition states developed for assessment of concrete cast-in-place bridge decks.
The proposed condition states include basic quantitative information and address specific forms of deterioration consistently identified during inspection.
The Brooklyn Bridge stands as a monument of bridge engineering, and while easily accessible to the public, access for structural inspection is difficult.
As part of the 2006 biennial inspection of the Bridge, a detailed masonry inspection of the Manhattan and Brooklyn towers was conducted using rope access techniques to examine areas previously investigated only through remote visual methods.
In “The 2006 rope access inspection of the Brooklyn Bridge towers: a new view of an old bridge”, Schmidt discusses the access methods employed for a detailed inspection of the bridge tower masonry.
Challenges included performing this work without adding anchors to the towers, registration of inspection findings on a massive masonry structure in a repeatable format, and providing tactile inspection access in stone overhangs, beneath steel walkways and within recesses.
Bridge structures stand as landmarks of aesthetics and monument of engineering ingenuity. On the theme of historic bridges, Melewski et al take the reader along a “Walkway over The Hudson (historic bridge to northeast recreational destination)”.
The paper discusses the historic significance of the Poughkeepsie Railroad Bridge, which was opened in 1888. It was the longest bridge in the world when the first train crossed it.
As the first bridge constructed across the Hudson River between New York City and Albany, the bridge had an enormous impact on transportation throughout the Northeast United States.
After a long history of ownership and uses, the bridge suffered damage from a fire in 1974 that rendered it unusable for railroad traffic.
A comprehensive study has begun to certify structural integrity and to produce a plan to establish it as a public park and walkway, as well as a bridge engineering educational resource.
The paper provides a brief historic overview, discusses the objectives of the comprehensive study and the findings of the late 2006 underwater inspections.
In “Aesthetics and durability aspects in the realization of small and medium span arch bridges” Siviero and Zanchettin present the importance of function and its harmony with the surrounding environment.
The authors discuss the value of aesthetics within the context of long lasting durability. In January of 1886, an American contractor,
Union Bridge Company of New York City, won an international competition to design and build a two-track steel railroad bridge of approximately 3,000 feet in length over the Hawkesbury River in New South Wales, about 30 miles north of Sydney, Australia.
At the time it was the biggest public works project in the southern hemisphere. In his paper “Hawkesbury Railway Bridge near Sydney, Australia”, Gandhi gives a background of this project; details of 14 designs submitted by different contestants from England, France, Australia, and the US; construction methods; key individuals involved in this project; difficulties encountered during construction; and its successful completion.
The bridge was completed in 34 months and opened to traffic with great fanfare in May 1889. It linked the north and south regions of Australia.
The bridge was strengthened several times and ultimately replaced in 1946. Projects responsive to the purpose and needs defined by the stakeholders generate greater participation and ownership in the project.
Involving the community early builds support and minimizes resistance that sometimes develops in response to change.
Officials benefit by helping the public anticipate construction with the knowledge that any inconvenience will be rewarded by a structure that is responsive to the specific needs of the community.
In “Historic bridge replacement: a collaborative approach to context sensitive design”, Piotrowski and Chamberlin present architect’s experience in the replacement of the Royal Park Bascule Bridge, Florida, USA.
The contributions of an outstanding body of technical experts from all over the world ensure the archival value of this set of proceedings.
The presented material in this volume reflects state-of-the-art innovations in bridge engineering technology. The editor thanks the authors and expresses a special note of gratitude to the reviewers.
This volume is a result of the sacrifice of time and effort, dedication and collective wisdom of all contributors.
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