Editor’s Note

The May 2007 issue of the ASCE Journal of Bridge Engineering begins with an interesting paper on improving the fatigue strength of cover-plated rolled beams. In “Fatigue-Proofing Cover Plates,” Albrecht and Lenwari summarize all the fatigue test data on cover-plated steel beams since 1969. These studies established the fatigue limits for Category E and ${\mathrm{E}}^{\prime }$ details. Various techniques can be used to improve the mean fatigue life of the detail, hereby fatigue-proofing rolled beams with cover plates.

The next two papers are on the subject of bridge substructures. Dhakal, Mander, and Mashiko—in “Bidirectional Pseudodynamic Tests of Bridge Piers Designed to Different Standards”—discuss circular reinforced concrete highway bridge piers designed by using Caltrans, New Zealand, and Japanese specifications. The piers were experimentally tested to investigate and assess their seismic performance. Using 30% scaled models, specimens were subjected to a sequence of three different scaled earthquake ground motions. Damage states after the earthquakes were assessed and mapped for seismic risk assessment. The results for each of the specimens when exposed to different earthquake events are reported and discussed.

The second substructure paper is “Evaluation of Seasonal and Yearly Behavior of an Integral Abutment Bridge,” by Breña, Bonczar, Civjan, DeJong, and Crovo. This paper presents the field performance evaluation of an integral abutment bridge that has been monitored for three years with an emphasis on observing seasonal and yearly behavior. Fundamental parameters that control the response of the bridge were evaluated. The data that were collected indicated that the current design procedures are conservative in the state where this bridge was built.

The fourth and fifth papers are on the subject of concrete bridge superstructures. In their paper “Field Test and 3D FE Modeling of Decked Bulb-Tee Bridges,” Ma, Chaudhury, Millam, and Hulsey summarize the field testing and development of 3D finite-element modes for eight decked bulb-tee girder bridges. Parametric studies were performed by using calibrated 3D finite-element models to investigate the effect of shear connectors and intermediate diaphragms on live-load distribution and connector forces. The findings of their work are of interest to practicing engineers.

In “Structural Behavior of Single Key Joints in Precast Concrete Segmental Bridges,” by Issa and Abdalla, five full-depth shear keys were match cast and tested to examine the shear capacity of epoxy-jointed single keys. Another group of four specimens was cast and tested for fatigue and water tightness at a segment joint. Cold-weather and hot-weather epoxy types were used in the specimens; and in addition to experimental testing, finite-element analysis was used to model the static response of the joint specimens. The results of the tests are presented. The authors concluded that implementing AASHTO procedures resulted in conservative estimates of the shear strength of the single-keyed joint because the methods neglected the strength provided by the epoxy and underestimated the strength of the key.

The next three papers are on decks; two companion papers discuss concrete decks, and one discusses orthotropic decks. In the first companion paper, titled “Proposed Effective Width Criteria for Composite Bridge Girders,” Chen, Aref, Chiewanichakorn, and Ahn propose a simpler and more versatile design criteria for computing the effective width for steel-concrete composite girders. Finite-element modeling was used to conduct a parametric study, and scale specimens were used to obtain their results. They concluded that the full width of the deck could be used for both the positive and negative moment regions for both simple and continuous spans.

In the second companion paper titled “Effective Slab Width Definition for Negative Moment Regions of Composite Bridges,” Aref, Chiewanichakorn, Chen, and Ahn propose a more effective slab width definition for negative moment regions. Detailed calculations of effective slab width for negative moment regions using the proposed definition are summarized at the end of the paper.

The final deck paper is “Analysis of an Orthotropic Deck Stiffened with a Cement-Based Overlay.” This paper—by Walter, Olesen, Stang, and Vejrum—investigates the use of a cement-based overlay to enhance the stiffness of the traditional orthotropic deck to increase its fatigue safety. The results of their work are presented in the paper, along with the parameters that affect the performance of the system.

The ninth and tenth papers are on the subject of seismic effects on cable structures. In “Seismic Vulnerability and Mitigation during Construction of Cable-Stayed Bridges,” Wilson and Holmes examine the implications of earthquake loading during balanced cantilever construction of a cable-stayed bridge. The results of using finite-element analysis showed that there can be a high probability of having seismic responses in a partially completed bridge that exceed the 50-year design level of the completed bridge. The authors found that the tie-down cables intended for aerodynamic stability during construction could be used to mitigate the structure’s seismic vulnerability during construction.

Vader and McDaniel, in “Influence of Dampers on Seismic Response of Cable-Supported Bridge Towers,” present their work, which uses nonlinear time history analysis to investigate the seismic response of the new San Francisco–Oakland Bay Bridge East Span self-anchored suspension bridge and cable-stayed bridge alternative. The authors investigated the use of friction dampers and viscous dampers in lieu of the as-designed steel shear links. They conclude that the use of dampers provided better performance for the structure.

The 11th paper in this issue of the journal is titled “Assessment of AASHTO LRFD Specifications for Hybrid HPS 690W Steel I-Girders” and is by Barth, Righman, and Freeman. This paper describes the research conducted to determine the applicability of the second and third editions of the AASHTO LRFD Specifications to hybrid I-girders fabricated from high-performance steel flanges $\left(100\mathrm{ksi}\right)$ and high-performance steel webs $\left(70\mathrm{ksi}\right)$ . The paper specifically investigated the negative moment capacity prediction equations for noncomposite girders. The investigation was carried out by using three-dimensional nonlinear finite-element analysis to determine the ultimate bending capacity of a suite of hybrid girders. Further, a design study was performed to assess the economic feasibility of incorporating $100\mathrm{ksi}$ high-performance steel in traditional bridge applications. The results of the work indicated that the second and third editions of the specifications can be used.

The final paper in this issue of the journal is “Statistical Significance of Less Common Load Combinations” by Hida. This paper describes the work done by the author to develop a simple and rational basis for combining bridge loads in the extreme event limit state. Classic methods were used to evaluate the probabilities of various bridge loads occurring simultaneously and in various intensities. The results of this investigation are presented and should be of interest to practicing engineers.

Finally, there is a technical note by Harries and Moses. In “Effect on Superstructure Stress of Replacing a Composite RC Bridge Deck with a GFRP Deck,” the authors demonstrate through an illustrative example the implications of RC-to-GFRP deck replacement on superstructure stresses, as well as the loads on the substructure.