Editor’s Note

The September 2009 issue of the ASCE Journal of Bridge Engineering begins with two papers on the use of composites in bridges. In “Failure Load Test of a CFRP Strengthened Railway Bridge in Örnsköldsvik, Sweden,” Bergström, Täljsten, and Carolin present their work on strengthening concrete girders for a railway bridge for flexure to obtain required shear failure results from a bridge loaded to failure. Specific findings regarding probability for failure and the utilization of the carbon fiber-reinforced polymer (CFRP) strengthening are presented.

The second paper on composites is by Ziehl, Engelhardt, Fowler, Ulloa, Medlock, and Schell, and is titled “Design and Field Evaluation of a Hybrid FRP/Reinforced Concrete Superstructure System.” A hybrid fiber-reinforced polymer/reinforced concrete bridge was designed and constructed in Texas. The paper presents the design considerations, the bid process, and the results of intermittent live load evaluations that were conducted over a two-year period along with recommendations for the design of future similar bridges.

“Experimental Determination of Resistance Characteristics of Support Details Used in Prestressed Concrete Bridge Girders” by Baran, Rohne, French, and Schultz details the static load tests that were performed on support details at the ends of prestressed concrete pedestrian bridge girders. These tests were to determine the resistance characteristics of girder supports perpendicular to the girders longitudinal axis. The tests found two types of lateral load resisting mechanisms depending on the details of the support.

The fourth paper in this issue, by Fu and You, is titled “Truck Loads and Bridge Capacity Evaluation in China.” The paper describes the research work in developing reliability-based requirements for the bridges in China where there is still no nationwide specification for the safe load carrying capacity. A target reliability index was developed and based on this index the live load factors for bridge evaluation were developed in the study and proposed to be included in the national specifications for China.

Creep and shrinkage in concrete decks for composite concrete steel bridges can result in significant redistribution and increase in bending moments at continuity supports as well as deflection of the girders. Chaudhary, Pendharkar, and Nagpal in “Control of Creep and Shrinkage Effects in Steel Concrete Composite Bridges with Precast Decks” present the studies performed to control the creep and shrinkage effects for these types of structures. The authors developed a hybrid procedure to account for creep, shrinkage, and progressive cracking in concrete decks, and this procedure was used to perform these studies. The work found that moments and deflections can be controlled to a significant degree without putting constraints on design parameters by delaying the time of mobilization of composite action between the precast concrete deck panels and the steel section.

In “Equivalent Beam-Column Method to Estimate In-Plane Critical Loads of Parabolic Fixed Steel Arches,” Wei, Wu, Chen, and Wang propose a new equivalent beam-column method for estimating the corresponding in-plane critical loads of an arch. The method uses a buckling factor to evaluate the influence of the rise-to-span and a reduction factor to consider the effect of initial crookedness. The paper shows that the proposed method yields good results.

Park, Noh, Lee, and Voyiadjis, in “Identification of a Distribution of Stiffness Reduction in Reinforced Concrete Slab Bridges Subjected to Moving Loads” propose a method of determining the stiffness reduction in damaged reinforced concrete slab bridges under moving loads. The proposed method is more feasible than conventional element-based damage detection methods.

Orthotropic bridge decks are the subject of the next paper in this issue of the Journal of Bridge Engineering. “Effects of Fabrication Procedures on Fatigue Resistance of Welded Joints in Steel Orthotropic Decks” by Sim, Uang, and Sikorsky investigated the effects of both weld melt-through and distortion control measures for the fatigue resistance of the rib-to-deck plate welded joint using six full-scale, two-span, orthotropic deck specimens.

The following two papers are historical papers. “O. Chanute, C.E.” by Griggs and Biggs presents a biography on Octave Chanute, a leading civil engineer in the U.S. from 1850 to 1890. After an unsurpassed career working on eastern and western railroads, he began his study in the work of others in the area of manned flight, designing and testing many of his own gliders.

The last paper is also authored by Griggs and is titled “Bridge across the Hudson.” This paper describes the many famous engineers who planned bridges across the Hudson but it was not until 1931 when Amman’s George Washington Bridge finally spanned the river.

There is a discussion of the paper “Effect of Near-Fault Vertical Ground Motions on Seismic Response on Highway Overcrossings” by Yi and Yin. The authors of the paper provide a closure for the discussion.