Joseph B. Strauss, Charles A. Ellis, and the Golden Gate Bridge: Justice at Last

The Golden Gate Bridge is one of the best-known engineering structures in the world and was the longest suspension bridge in the world for many years. Its design has generally been attributed to Joseph Strauss, but recent evidence proves that Charles Ellis was the prime designer of the bridge between 1929 and 1931. Strauss fired Ellis in late 1931 and systematically removed any mention of Ellis’ name in his final report on the bridge issued in 1938. It remained for John van der Zee in his book The Gate to set the record straight. This paper makes the case that Strauss violated one of the fundamental ethical canons—that of giving credit where credit is due.     

Cabin John Bridge: Role of Alfred L. Rives, C.E.

The Cabin John Bridge (CJB), located just outside Washington, D.C., is a masonry arch with a central angle of 110°, an intrados radius of 40.9 m (134 ft), and a span of 67 m (220 ft). Construction of the bridge began in 1857 but was not completed until late in 1863 because of suspensions due to lack of appropriations and the Civil War. The CJB is part of the Washington Aqueduct (WA) and is still the longest single-span masonry arch in the United States. The bridge was designated a National Historic Civil Engineering Landmark by the ASCE in 1972. The paper provides context for the bridge design and explains the construction technologies that were used. In the process, French and British influences on American masonry arch design practices at mid-19th century are revealed. The respective roles of Captain Montgomery C. Meigs, the chief engineer of the WA, and Alfred Landon Rives, his assistant engineer, are critically assessed. The paper provides, for the first time, relevant facts on Rives’ education and engineering career. The performance of the bridge over 145 years is reviewed and discussed.     

Engineering the Tower and Main Span Construction of Stonecutters Bridge

Stonecutters Bridge is the second longest cable-stayed bridge in the world and the first major bridge with a twin-box girder superstructure. It has a number of innovative structural features which made the construction of the bridge a significant challenge. This paper describes the fabrication and erection procedures for the bridge towers and the main span superstructure. These were developed in close interaction between the contractor and his construction engineering consultant to ensure a safe and effective construction. A stage-by-stage analysis was set up to model every step of the main span erection. The results were first used in the verification analyses to establish the adequacy of the permanent works throughout construction. In parallel, extensive wind tunnel testing as well as numerical analyses were performed to ascertain the effects of typhoon wind loads on the structure. The structural deformations predicted by the erection analysis were incorporated into a comprehensive geometric control procedure. This paper describes the construction methodologies developed and the related engineering input. It outlines studies undertaken to achieve an effective construction, ensure structural adequacy of all erection stages, ascertain an acceptable aerodynamic performance of the bridge, and exercise full control over the bridge geometry throughout erection.     

Analytical and Field Investigation of Roma Suspension Bridge

The Roma–Ciudad Miguel Aleman International Suspension Bridge is an historic unstiffened suspension bridge with a 192 m (630 ft) main suspended span, originally constructed in 1928. In 1997 the bridge was inspected and a full-scale nondestructive load test was conducted. The resulting experimental data are evaluated and compared to the results of analyses by finite-element method modeling. The history of the bridge is reviewed, with an emphasis on modifications and retrofits to the structure. The unique behavior and attributes of unstiffened suspension bridges are discussed in the specific context of this particular bridge.     

Wheel Load Distribution in Simply Supported Concrete Slab Bridges

This paper presents the results of a parametric study related to the wheel load distribution in one-span, simply supported, multilane, reinforced concrete slab bridges. The finite-element method was used to investigate the effect of span length, slab width with and without shoulders, and wheel load conditions on typical bridges. A total of 112 highway bridge case studies were analyzed. It was assumed that the bridges were stand-alone structures carrying one-way traffic. The finite-element analysis (FEA) results of one-, two-, three-, and four-lane bridges are presented in combination with four typical span lengths. Bridges were loaded with highway design truck HS20 placed at critical locations in the longitudinal direction of each lane. Two possible transverse truck positions were considered: (1) Centered loading condition where design trucks are assumed to be traveling in the center of each lane; and (2) edge loading condition where the design trucks are placed close to one edge of the slab with the absolute minimum spacing between adjacent trucks. FEA results for bridges subjected to edge loading showed that the AASHTO standard specifications procedure overestimates the bending moment by 30% for one lane and a span length less than 7.5 m (25 ft) but agrees with FEA bending moments for longer spans. The AASHTO bending moment gave results similar to those of the FEA when considering two or more lanes and a span length less than 10.5 m (35 ft). However, as the span length increases, AASHTO underestimates the FEA bending moment by 15 to 30%. It was shown that the presence of shoulders on both sides of the bridge increases the load-carrying capacity of the bridge due to the increase in slab width. An extreme loading scenario was created by introducing a disabled truck near the edge in addition to design trucks in other lanes placed as close as possible to the disabled truck. For this extreme loading condition, AASHTO procedure gave similar results to the FEA longitudinal bending moments for spans up to 7.5 m (25 ft) and underestimated the FEA (20 to 40%) for spans between 9 and 16.5 m (30 and 55 ft), regardless of the number of lanes. The new AASHTO load and resistance factor design (LRFD) bridge design specifications overestimate the bending moments for normal traffic on bridges. However, LRFD procedure gives results similar to those of the FEA edge+truck loading condition. Furthermore, the FEA results showed that edge beams must be considered in multilane slab bridges with a span length ranging between 6 and 16.5 m (20 and 55 ft). This paper will assist bridge engineers in performing realistic designs of simply supported, multilane, reinforced concrete slab bridges as well as evaluating the load-carrying capacity of existing highway bridges.     

Optimum Design of Welded Steel Plate Girder Bridges Using a Genetic Algorithm with Elitism

The genetic algorithm (GA) is a general optimization technique that has some unique features that are especially suitable for structural engineering problems. This work uses a simple GA with elitism to find the optimum design of welded steel plate girder bridges. The objectives are to minimize the weight and the cost of the girders. Two types of plate-girder bridges are studied: a single-span bridge and a two-equal-span continuous bridge. Bridges with various span lengths, in increments of 20?ft, are investigated; results are tabulated, parametric studies are made, and meaningful conclusions are drawn.     

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.”     

Tests During Three Stages of Construction of a Road Bridge with a Flexible Load-Carrying Structure Made of Super Cor Type Steel Corrugated Plates Interacting with Soil

The way in which a new road bridge made of steel corrugated plates Super Cor type was tested during the three stages of its construction is described and the test results are presented. Backfill in construction Stage I and two ballasting vehicles in Stages II and III constituted the loads. The box bridge spans the Bystrzyca Dusznicka River in Polanica Zdroj, Poland. The span’s effective length is 12.27?m and its vertical inside diameter is 3.85?m. The steel span is founded on two reinforced concrete strip foundations. The average values of the displacements and strains (normal stresses) measured in selected points and on selected elements of the steel shell structure were much smaller than the ones computed for the same load. The conclusions drawn from this research can be helpful in determining the interaction between the steel shell and the backfill. Since this type of steel–soil structure is increasingly used in Poland and in the world, the conclusions can be generalized to a whole class of similar bridge designs.     

Dynamic and Impact Behavior of Half-Through Arch Bridges

The objective of this paper is to present the results of an investigation of the dynamic and impact characteristics of half-through arch bridges with rough decks caused by vehicles moving across them. Seven arch bridges modeled as three-dimensional structures with overall span lengths ranging from 20?to?200?m (65.5?to?656.2?ft) are analyzed. The American Association of State Highway and Transportation Officials Specifications HS20-44 truck is the applied vehicle loading used in the analysis and is simulated as a three-dimensional, nonlinear vehicle model with 11 degrees of freedom. Truck components include the body, suspension, and tires. The bridge deck surface is assumed to have a “good” surface roughness and is simulated using a stochastic process (power spectral density function). The effect on impact factors of span length, rise-to-span ratio, and vehicle speed is discussed. The results of the analyses show that the impact factors of bending moment and axial force will not exceed 0.4 and 0.25, respectively. The proposed impact equations are simple and conservative and can be used in the design of half-through arch bridges.     

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.     

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.     

Determination of Bridge Design Parameters through Field Evaluation of the Route 601 Bridge Utilizing Fiber-Reinforced Polymer Girders

The Route 601 Bridge in Sugar Grove, Virginia, spans 11.89?m (39?ft) over Dickey Creek. The bridge is the first to use the Strongwell 91.4?cm (36?in.) deep fiber-reinforced polymer double web beam in a vehicular bridge superstructure. Construction of the new bridge was completed in October 2001 and field testing was undertaken shortly thereafter, as well as in June of 2002, to assess any potential changes in structural performance. This paper details the field evaluation of the Route 601 Bridge. Using midspan deflection and strain data from the October 2001 and June 2002 field tests, AASHTO bridge design parameters were determined—namely, wheel load distribution factor g, dynamic load allowance IM, and maximum deflection. The wheel load distribution factor was determined to be S/4, a dynamic load allowance was determined to be 0.36, and the maximum deflection of the bridge was L/1,110. Deflection results were lower than the AASHTO L/800 limit. This discrepancy is attributed to partial composite action of the deck-to-girder connections, bearing restraint at the supports, and contribution of guardrail stiffness. It was found that diaphragm removal had a small effect on the wheel load distribution factor.     

Analytic Model of Long-Span Self-Shored Arch Bridge

An innovative self-shoring staged construction method was developed to build the world’s longest reinforced composite concrete arch bridge across the Yangtze River at Wanxian, in Chongqing, China. The method uses a steel tube truss frame constructed by the conventional cantilever launching technique. This steel frame with concrete-filled tubes performs the dual role of arch falsework and arch main reinforcement for the final reinforced concrete arch bridge. An optimized schedule for concrete placement was proposed to control the stresses, deflections, and stability of the arch rib during construction. The time dependent effects of concrete, the nonlinear stress-strain relationship of steel and concrete, as well as the geometric nonlinearility were considered. Control information at various stages of construction can be provided using the model developed. A program was developed to conduct parametric studies for selection of the final construction scheme and to direct the construction progress by monitoring and comparing actual and predicted stress and deflection.     

Dynamic Behavior of Steel Deck Tension-Tied Arch Bridges to Seismic Excitation

The dynamic responses of steel deck, tension-tied, arch bridges subjected to earthquake excitations were investigated. The 620 ft (189 m) Birmingham Bridge, located in Pittsburgh, was selected as an analytical model for the study. The bridge has a single deck tension-tied arch span and is supported by two bridge piers, which in turn are supported by the pile foundations. Due to the complex configuration of the deck system, two analytical models were considered to represent the bridge deck system. Using the normal mode method, seismic responses were calculated for two bridge models and the results were compared with each other. Three orthogonal records of the El Centro 1940 earthquake were used as input for the seismic response analysis. The modal contributions were also checked in order to obtain a reasonable representation of the response and to minimize computational cost. Displacements and stresses at the panel points of the bridge are calculated and presented in graphical form.     

Kentucky River High Bridge

Cantilever bridge construction can be said to have started with the work of Heinrich Gerber in Germany in 1867. While the principle had been used in many ancient bridges, it was not until Gerber’s work that metal bridges were built using the cantilever principle. The Kentucky High Bridge over the Kentucky River was the first modern cantilever bridge built in the United States. While James Eads had used the cantilever construction method at St. Louis, his bridge acted in service as a series of three arches. The High Bridge, designed by C. Shaler Smith, was one of the most daring and innovative bridges built in the country and carried its load between 1876 and 1912, when it was replaced by Gustave Lindenthal’s three span truss.     

Collapse of the Quebec Bridge, 1907

In the late 19th century, the transportation needs of Quebec led to proposals for bridging the St. Lawrence River. The Quebec Bridge was the longest cantilever structure attempted until that time. In its final design, the clear span was 548.6 m (1,800 ft) long. The bridge project was financially troubled from the beginning. This caused many setbacks in the design and construction. Construction finally began in October 1900. In August 1907, the bridge collapsed suddenly. Seventy five workers were killed in the accident, and there were only 11 survivors from the workers on the span. A distinguished panel was assembled to investigate the disaster. The panel’s report found that the main cause of the bridge’s failure was improper design of the latticing on the compression chords. The collapse was initiated by the buckling failure of Chord A9L, on the anchor arm near the pier, immediately followed by Chord A9R. Theodore Cooper had been the consulting engineer for the Quebec Bridge project, and most of the blame for the disaster fell on his shoulders. He mandated unusually high allowable stresses, and failed to require recalculation of the bridge dead load when the span was lengthened.     

Equivalent Wheel Load Approach for Slender Cable-Stayed Bridge Fatigue Assessment under Traffic and Wind: Feasibility Study

In the current AASHTO LRFD specifications, the fatigue design considers only one design truck per bridge with 15% dynamic allowance. While this empirical approach may be practical for regular short and medium span bridges, it may not be rational for long-span bridges (e.g., span length >152.4?m or 500?ft) that may carry many heavy trucks simultaneously. Some existent studies suggested that fatigue may not control the design for many small and medium bridges. However, little research on the fatigue performance of long-span bridges subjected to both wind and traffic has been reported and if fatigue could become a dominant issue for such a long-span bridge design is still not clear. Regardless if the current fatigue design specifications are sufficient or not, a real understanding of the traffic effects on bridge performance including fatigue is desirable since the one truck per bridge for fatigue design does not represent the actual traffic condition. As the first step toward the study of fatigue performance of long-span cable-stayed bridges under both busy traffic and wind, the equivalent dynamic wheel load approach is proposed in the current study to simplify the analysis procedure. Based on full interaction analyses of a single-vehicle–bridge–wind system, the dynamic wheel load of the vehicle acting on the bridge can be obtained for a given vehicle type, wind, and driving condition. As a result, the dimension of the coupled equations is independent of the number of vehicles, through which the analyses can be significantly simplified. Such simplification is the key step toward the future fatigue analysis of long-span bridges under a combined action of wind and actual traffic conditions.     

Design of Looping Cable Anchorage System for New San Francisco–Oakland Bay Bridge Main Suspension Span

Located at the rocky edge of the Yerba Buena Island, the west anchorage of the San Francisco–Oakland Bay Bridge suspension span serves as the anchor for this single tower self-anchored suspension bridge. With extensive comparative studies on numerous alternatives, the new looping cable anchorage system is recommended for the final design of the west anchorage of the self-anchored suspension span. The looping cable anchorage system essentially consists of a prestressed concrete portal frame, a looping anchorage cable, deviation saddles, a jacking saddle, independent tie-down systems, and gravity reinforced-concrete foundations. This anchorage system is chosen for its structural efficiency and dimensional compactness. This paper describes major design issues, design philosophy, concept development, and key structural elements and details of this innovative suspension cable anchorage system.     

Autoparametric Resonance in a Pedestrian Steel Arch Bridge: Solferino Bridge, Paris

Autoparametric resonance is treated as the reason of arising excessive lateral vibrations in the steel arch bridge (the Solferino Bridge). To explain this phenomenon, a physical model (a double pendulum) is proposed. Its behavior, as a rule, depends on dynamic characteristics of a bridge rather than on its type. The response of a two degree-of-freedom system with quadratic nonlinearities in the presence of two-to-one autoparametric resonance is investigated. The perturbation method of multiple time scales is used to construct first-order nonlinear differential equations and to determine steady state solutions and their stability. Bifurcation analysis is performed to determine a critical (threshold) value in the external load (control) parameter. The autoparametric resonance becomes possible if an excited torsional mode is near a primary resonance and an external load parameter caused by pedestrians is equal or higher than its critical value. When the increasing load parameter passes through the critical value (because a quantity of pedestrians on the bridge is increased), a jump phenomenon (or fast growth) is observed for the lateral mode, the torsional mode is saturated and has much smaller amplitudes. Field tests were held to understand a phenomenon of an excessive lateral movement, and to enforce the Solferino Bridge. Theoretical results of the present paper are compared with those experimental measurements. Swaying of pedestrian bridges can be treated as a two-step process. The first step (achievement of parametric resonance), described in this paper, is the condition for the beginning of the second step—the process of possible synchronization of applied forces and the interactions between them and the lateral and torsional modes of vibration.     

Carbon Fiber-Reinforced Polymer Strengthening and Monitoring of the Gr?ndals Bridge in Sweden

The Gr?ndal Bridge is a large freivorbau bridge (prestressed concrete box bridge), approximately 400?m in length with a free span of 120?m. It was opened to tram traffic in the year 2000. Just after opening cracks were noticed in the webs, these cracks have then increased, the size of the largest cracks exceeded 0.5?mm, and at the end of 2001 the bridge was temporarily strengthened. This was carried out with externally placed prestressed steel stays. The reason for the cracking is still debated and will be further discussed in this paper. Nevertheless, it was clear that the bridge needed to be strengthened. The strengthening methods used were CFRP plates at the serviceability limit state and prestressed dywidag stays at the ultimate limit state. The strengthening was carried out during 2002. At the same time monitoring of the bridge commenced, using LVDT crack gauges as well as optical fiber sensors.