Niagara Cantilever

The first modern metal cantilever bridge in the United States, using erection methods that were to be utilized in most future cantilever bridges, was by C. C. Schneider across the Niagara Gorge in 1883. The Niagara, saw in order, John Roebling’s Railroad Suspension Bridge, Samuel Keefer’s Honeymoon Suspension Bridge, Edward Serrell’s Lewiston-Queenston Suspension Bridge, Schneider’s cantilever, Leffert Buck’s arch bridge at the falls as well as Buck’s arch built under Roebling’s suspension bridge. Schneider’s bridge had a useful life of over 40 years during a period when rolling stock on the railroads was increasing rapidly. The speed of erection of a new style bridge coupled with its performance makes it one of the most innovative and significant bridges built in the world at the time.     

C. Shaler Smith

Smith was one of the premier bridge builders of the post-Civil War period. He started his bridge building career under Albert Fink on the Louisville and Nashville Railroad. During the Civil War, he designed and built a powder factory for the Confederacy at Augusta, Ga. After the war, he formed Smith and Latrobe Co. and later The Baltimore Bridge Company with Benjamin and C. H. Latrobe. He worked closely with James Eads on the St. Louis Bridge and designed and built the long iron easterly approach to the bridge. He designed and built some of the major viaducts, swing, and fixed span bridges in the United States, Australia, and Peru, and finally innovative cantilever bridges over the Kentucky, Mississippi, and St. Lawrence Rivers.     

Development of the Vertical Lift Bridge: Squire Whipple to J. A. L. Waddell, 1872–1917

The development of canals started in the mid 18th century in England and Europe and in the 1820s in the United States. They required the design and construction of many bridges to provide canal crossings for carriages, wagons, animal herds, and pedestrians. The cost of building bridges of masonry or wood to carry roadway traffic high over the towpaths and waterways of canals was very great so engineers of the day developed bridges that could be moved out of the way when a canal boat was coming through and then moved back over the canal to provide roadway access. The Dutch developed a type of bascule bridge for many canals, while the British developed swing or pull back bridges. The swing bridge for narrow canals had a turntable on shore with a short counterweight span over land and a cantilever span over the canal. This bridge could be worked by hand with a simple crank. The pull back bridges, while not as common, ran on tracks and had the same type of counterweight span and cantilever span over the canal. On wide canals, as well as on the C & O Canal in the 1830s, the swing bridges had a central pier on which the turntable was mounted and the bridge cantilevered out on both sides to the shore when closed, and frequently onto an extended pier parallel to the canal when the bridge was open for canal boat passage. In the United States the most common bridge on canals and waterways was a side mounted or center mounted swing bridge well into the 20th century. The development of the metal vertical lift bridge can be traced to the late 1840s in England where several small lift spans were built. After a review of early European spans, this paper covers the period starting in 1872 with Squire Whipple and his Erie Canal bridges, and terminates in 1917 with Waddell’s Columbia River Bridge.     

Timothy Palmer and the Permanent Bridge

Timothy Palmer had built notable bridges across the Merrimack, Kennebec, Connecticut, and Potomac Rivers and across the Great Bay of the Piscataqua River in Maine when he was selected to build the first permanent, as contrasted to a floating, bridge across the Schuylkill River at Philadelphia in 1803. The bridge was the first covered bridge in the United States and its 195-ft central span was second only to his Piscataqua Bridge in span length. He has been called the “Nestor of American Bridge Builders.”     

Development of the Lenticular Truss Bridge in America

Lenticular-shaped iron truss bridges, built exclusively by the Berlin Bridge Company of East Berlin, Conn., dominated the New England and adjacent area’s modest span bridge market for over a decade at the end of the nineteenth century. This paper examines this phenomenon in the larger context of earlier European development of the lenticular form and, with the assistance of numerous patent drawings and photographs of American lenticular bridges that were either proposed or built prior to the 1883 formation of the Berlin Bridge Company.     

Seismic Vulnerability and Mitigation during Construction of Cable-Stayed Bridges

The implications of earthquake loading during balanced cantilever construction of a cable-stayed bridge are examined. Finite-element models of a cable-stayed bridge were developed and multiple ground motion time history records were used to study the seismic response at the base of the towers for six stages of balanced cantilever construction. Probabilistic seismic hazard relationships were used to relate ground motions to bridge responses. The results show that there can be a high probability of having seismic responses (forces/moments) in a partially completed bridge that exceed, often by a substantial margin, the 10%/50-year design level (0.21% per annum) for the full bridge. The maximum probability of exceedance per annum was found to be 20%. This occurs because during balanced-cantilever construction the structure is in a particularly precarious and vulnerable state. The efficacy of a seismic mitigation strategy based on the use of tie-down cables intended for aerodynamic stability during construction was investigated. This strategy was successful in reducing some of the seismic vulnerabilities so that probabilities of exceedance during construction dropped to below 1% per annum. Although applied to only one cable-stayed bridge, the same approach can be used for construction-stage vulnerability analysis of other long-span bridges.     

Field Experiments and Numerical Models for the Condition Assessment of Historic Timber Bridges: Case Study

Covered wooden bridges and the principles of heavy timber framing by which they were built represent both a significant chapter in this country’s civil engineering heritage, and a subclass of bridges that are in immediate need of repair and rehabilitation. This work often falls on the shoulders of the municipalities who own the bridges or local consulting engineering companies, neither of which have the resources to perform state-of-the-art damage assessment analyses. This study presents two case studies in which a simplified approach to damage assessment is used. The writers explore the importance of proper condition assessments, including both field observations and load tests, to the creation of viable finite-element models that practicing engineers may use in their repair and rehabilitation of these unique structures. Experimental tests were performed on two covered bridges: Morgan Bridge in Belvidere, Vermont and Pine Grove Bridge, in Oxford, Pennsylvania, and comparisons were made to finite-element models created of those bridges. The combination of experimental and numerical tools led to the identification of several deteriorated components, including scarf joints, lapped brace joints, and retrofitted members within the bridges that may have otherwise gone undetected.     

Verification of Incremental Launching Construction Safety for the Ilsun Bridge, the World’s Longest and Widest Prestressed Concrete Box Girder with Corrugated Steel Web Section

The Ilsun Bridge is the world’s longest (801?m in total length) and widest (30.9?m in maximum width) prestressed concrete box girder bridge incorporating a corrugated steel web. This bridge has fourteen spans, twelve of which were erected using an incremental launching method, a method that is rarely applied in this type of bridge. To verify the construction safety of the Ilsun Bridge, this investigation focuses on the span-to-depth ratio, buckling shear stress of the corrugated steel webs, optimization of the length of the steel launching nose, detailed construction stage analysis, and the stress level endured by the corrugated steel webs during the launching process. The span-to-depth ratio of the Ilsun Bridge was found to be well-designed, using a conservative corrugated steel web design. Further, our investigation revealed that the conventional nose-deck interaction equation was not suitable for corrugated steel web bridges. As a result, a detailed construction stage analysis and measurements of this bridge was performed to examine stress levels and ensure safety during the erection process. The results revealed that there are essential design issues that should be considered when designing prestressed concrete box girder bridges with corrugated steel webs and that, when constructing them, the incremental launching method should be used.     

Poughkeepsie Bridge: Its Birth, Abandonment, and Rebirth

When opened the Poughkeepsie Bridge incorporated the longest span—548 ft—cantilever in the world; the longest simple span, 525 ft; and its overall length, 6,767 ft, was for a short time the longest bridge in the world. Between 1871 and 1889, its opening, some of the leading engineers and railroad men had been involved in its planning and design including three future presidents of ASCE. Construction is currently under way to convert the bridge to a pedestrian/bicycle pathway across the Hudson River.     

Repair of New Long-Span Bridges Damaged by the 1995 Kobe Earthquake

The 1995 Hyogo-ken Nanbu (Kobe), Japan earthquake provided the world’s first experience with earthquake damage to new long-span bridges designed to 1990s seismic standards. This paper reviews damage and describes techniques used to repair three major steel bridges along the Wangan route (Bayshore route) in Kobe—the 885 m Higashi-Kobe Bridge, the 217 m Rokko Island Bridge, and the 252 m Nishinomiya Port Bridge. These bridges, in service for less than three years, were essential components in the highway transportation system in the Kobe region. Extremely large ground motions, and failure of bearings, connections, and seismic restrainers were principal contributors to the damage sustained by these bridges. Repairs utilized heavy-lift floating cranes (up to 4,100 ton capacity) and various jacks to stabilize the structures and to realign spans. In one case, reconstruction of a collapsed span was required, with lifting weight a prime concern. Significant constraints on the repair included confined working space and requirements for maintaining maritime navigational clearances. The closure times for the repair of the bridges ranged from three to nine months.     

Bayonne Bridge: The Work of Othmar Ammann, Master Builder

The goal of this paper is to demonstrate the significance of the Bayonne Bridge and to identify it as a work of structural art, because its designer, Othmar Ammann (1879–1965), focused on efficiency, economy, and elegance. To understand Ammann’s ideas and his great arch bridge, we will: (1) briefly describe his educational background; (2) explore his design concept; (3) explain the behavior of the bridge through a careful structural analysis; (4) include a critical analysis of its design; and (5) reflect on lessons to be learned from Ammann. A full, modern technical study of the Bayonne Bridge has never been published. Since we are very fortunate to have one of the few complete sets of the plans, we will present an independent structural analysis to explain Ammann’s design concept and to demonstrate its efficiency in the complete form and its safety during construction.     

Dynamic Response of Three Fiber Reinforced Polymer Composite Bridges

Fiber reinforced polymer (FRP) composite bridge decks are gaining the attention of bridge owners because of their light self-weight, corrosion resistance, and ease of installation. Constructed Facilities Center at West Virginia University working with the Federal Highway Administration and West Virginia Department of Transportation has developed three different FRP decking systems and installed several FRP deck bridges in West Virginia. These FRP bridge decks are lighter in weight than comparable concrete systems and therefore their dynamic performance is equally as important as their static performance. In the current study dynamic tests were performed on three FRP deck bridges, namely, Katy Truss Bridge, Market Street Bridge, and Laurel Lick Bridge, in the state of West Virginia. The dynamic response parameters evaluated for the three bridges include dynamic load allowance (DLA) factors, natural frequencies, damping ratios, and deck accelerations caused by moving test trucks. It was found that the DLA factors for Katy Truss and Market Street bridges are within the AASHTO 1998 LRFD specifications, but the deck accelerations were found to be high for both these bridges. DLA factors for Laurel Lick bridge were found to be as high as 93% against the typical design value of 33%; however absolute deck stress induced by vehicle loads is less than 10% of the deck ultimate stress.     

Design and Evaluation of Experimental Bridges in Tennessee

This paper describes the design and evaluates the adequacy of the moment connection of an experimental two-span highway bridge designed by the Tennessee Department of Transportation. The Massman Drive Bridge is an experimental design that unifies the construction economy of simple span bridges and the structural economy of continuous span bridges. The experimental connection, consisting of cover plates and kicker wedge plates, is used to connect the two adjoining girders over the center pier. As a result, the bridge is designed to function as a continuous bridge during the deck pour and behave compositely with the reinforced concrete deck under the live load. After completing a moment comparison analysis, it is concluded that the Massman Drive Bridge indeed acts as continuous over the pier as it was designed.     

Impact Factors for Curved Continuous Composite Multiple-Box Girder Bridges

The results from a parametric study on the impact factors for 180 curved continuous composite multiple-box girder bridges are presented. Expressions for the impact factors for tangential flexural stresses, deflection, shear forces and reactions are deduced for AASHTO truck loading. The finite-element method was utilized to model the bridges as three-dimensional structures. The vehicle axle used in the analysis was simulated as a pair of concentrated forces moving along the concrete deck in a circumferential path with a constant speed. The effects of bridge configurations, loading positions, and vehicle speed on the impact factors were examined. Bridge configurations included span length, span-to-radius of curvature ratio, number of lanes, and number of boxes. The effect of the mass of the vehicle on the dynamic response of the bridges is also investigated. The data generated from the parametric study and the deduced expressions for the impact factors would enable bridge engineers to design curved continuous composite multiple-box girder bridges more reliably and economically.     

Dynamic Monitoring of Steel Girder Highway Bridge

Currently there are different monitoring techniques that have been considered for use in the structural evaluation of bridges. These include approaches based on both static and dynamic behavior. The use of dynamic properties has advantages over static properties, since components of the dynamic properties are only marginally influenced by variations in the loading. When dynamic properties are used, field studies have shown that it is not always sufficient to use only natural frequencies and modal displacements. Some research for structural evaluation of bridges indicates that techniques based on use of derivatives of the natural frequencies and the modal displacements may be more effectively used to generate effective diagnostic parameters for structural identification. This paper presents the results of applying one of these methods, the modal flexibility approach, to a field study of a bridge in which the bearings were partially restrained in colder weather. While others have used impact methods with the modal flexibility method, in this study the approach is modified so that excitation is provided by vehicular traffic. The results show that the modified modal flexibility method provides a clear indication that there have been changes in the bridge’s structural behavior.     

Development of FRP Short-Span Deployable Bridge—Experimental Results

For military and civilian applications, there exists a need for lightweight, inexpensive, short-span bridges that can be easily transported and erected with minimal equipment. Owing to its favorable properties, fiber-reinforced polymer (FRP) has been shown to be feasible for the construction of such bridges. Investigations into the behavior of a short-span bridge structural concept, adapted to the material properties of commercially available glass FRP (GFRP) pultruded products, are presented. A 4.8-m span prototype was built from GFRP sections, bonded throughout to form a tapered box beam, with a width of 1.2?m and a height at midspan of approximately 0.5?m. The box beam represents a single trackway of a double-trackway bridge, whose trackways could be connected by light structural elements. The quasi-static and dynamic behavior of the prototype box beam was investigated in ambient laboratory and field conditions to assess the design and construction techniques used, with a view to designing a full-scale 10-m GFRP bridge. Laboratory testing of the prototype box beam used single and pairs of patch loads to simulate wheel loading. These tests confirmed that the box beam had sufficient stiffness and strength to function effectively as a single trackway of a small span bridge. Field testing of the structure was undertaken using a Bison vehicle (13,000?kg), driven at varying speeds over the structure to establish its response to realistic vehicle loads and the effects of their movement across the span.     

Finite-Element Modeling of Bridge Deck Connection Details

Many steel bridges built prior to 1960 have bridge deck connections that are subject to high cycle fatigue. These connections may be nearing their fatigue limit and will require increased inspection and repair over the next 10–20 years. The Winchester Bridge on Interstate 5 in Roseburg, Ore., required the extensive replacement of connection details because of fatigue crack growth. This report describes the results of a study to assess the loading conditions for the connection details on the Winchester Bridge. Finite-element modeling methods were used to characterize the structure, on both a global and local level. The global model provided the boundary conditions for the local model of the connection details. The local model included the effects of rivet preload and friction. Finite-element analysis results were validated by hand calculation. The analysis showed significant variation in connection detail stress range, depending on the detail’s longitudinal and lateral location.     

Reliability Analysis of Suspension Bridges against Fatigue Failure from the Gusting of Wind

A fatigue reliability analysis of suspension bridges due to the gustiness of the wind velocity is presented by combining overall concepts of bridge aerodynamics, fatigue analysis, and reliability analysis. For this purpose, the fluctuating response of the bridge deck is obtained for buffeting force using a finite-element method and a spectral analysis in frequency domain. Annual cumulative fatigue damage is calculated using Palmgren–Miner’s rule, stress-fatigue curve approach and different forms of distribution for stress range. In order to evaluate the reliability, both first-order second-moment (FOSM) method and full distribution procedure (assuming Weibull distribution for fatigue life) are used to evaluate the fatigue reliability. Probabilities of fatigue failure of the Thomas Bridge and the Golden Gate Bridge for a number of important parametric variations are obtained in order to make some general observations on the fatigue reliability of suspension bridges. The results of the study show that the FOSM method predicts a higher value of the probability of fatigue failure as compared to the full distribution method. Further, the distribution of stress range used in the analysis has a significant effect on the calculated probability of fatigue failure in suspension bridges.