Bridge Structures - Volume 3, issue 2

Authors: Mahmoud, Khaled M.

Article Type: Other

DOI: 10.1080/15732480701520030

Citation: Bridge Structures, vol. 3, no. 2, pp. 91-91, 2007

Authors: Yarnold, Matthew T. | Wilson, John L. | Jen, Wan-Chun | Yen, Ben T.

Article Type: Research Article

Abstract: This paper compares the behavior of local buckling in trapezoidal rib orthotropic bridge deck systems. The primary objective of this paper is to compare the condition of a uniform stress pattern (column) and that of a non-uniform stress pattern (beam-column). The former is current practice while the latter is recommended based on the current study. The presence of thin steel plate members within the deck system causes local buckling to be a valid concern. Parametric analyses were performed using the finite element method to compare local buckling of the rib walls (webs) and deck plate by varying the corresponding width-to-thickness …ratios. Since the rib walls have the highest width-to-thickness ratio, they were the primary focus of this research. Generally, this type of deck system is analyzed under axial compression due to global forces. However, bending moments from the local loading of the deck weight and vehicles are typically present in the system. Therefore, the bridge deck system was analyzed under axial compression and negative bending moment for local buckling in the rib walls. The results demonstrate a reduction in the capacity of the deck system at which local buckling is initiated in the rib walls due to the existence of negative bending moment near the floorbeams in addition to the global axial forces. Show more

Keywords: Orthotropic deck, Bridge, Local buckling, Deck, Rib, Finite element analysis

DOI: 10.1080/15732480701414341

Citation: Bridge Structures, vol. 3, no. 2, pp. 93-103, 2007

Authors: Huang, Haoxiong | Chajes, Michael J. | Mertz, Dennis R. | Shenton, Harry W. | Kaliakin, Victor N.

Article Type: Research Article

Abstract: The life cycle of grid decks has come full circle from their introduction in the 1920s and 1930s through their maturity in 1950s and 1960s to their reintroduction in the 1980s. Many of these decks have been performing satisfactorily over 50 or more years of service. Filled grid decks offer a lightweight and high strength deck alternative to reinforced concrete decks. Despite the good performance history of grid decks, some bridge owners are hesitant to utilize them. With a better understanding of grid deck behavior, the manufacturing process can be optimized, and design method improved. Hence, poor details can be …avoided and design efficiency can be achieved. This paper presents results of research conducted with the goal of providing a better understanding of filled steel grid deck behavior through experimental testing and numerical analyses. Three full-scale filled grid decks were tested to experimentally quantify their structural behavior. Three-dimensional finite element (FE) models were developed for the grid decks and calibrated using the experimental results. Finally, parametric studies were conducted and used to quantify the effect of variations in the significant design parameters. The results of the parametric studies can be applied to optimize future grid deck designs. It should be noted that crack width and ductility are important serviceability parameters in the performance of filled steel grid bridge decks. However, the work described in this paper is limited to strength issues and does not include evaluation of serviceability parameters. Show more

Keywords: Finite element analysis, Structural testing, Steel bridge grid decks

DOI: 10.1080/15732480701403872

Citation: Bridge Structures, vol. 3, no. 2, pp. 105-118, 2007

Authors: Hedjazi, Saman | Rahai, Alireza | Sennah, Khaled

Article Type: Research Article

Abstract: In this paper, time-dependent deflections, stresses and internal forces in prestressed concrete box-girder bridges due to creep of concrete are investigated. Simple equations, correlated with a step-by-step numerical simulation analysis, are developed to calculate long-term behavior of segmentally erected prestressed concrete box-girder bridges built by the balanced-cantilever method. Three-dimensional finite-element models of the mentioned bridges, including effects of the load history, material nonlinearity, creep and aging of concrete, were developed using ABAQUS software. The three-dimensional shell elements are used for modeling box-girder walls, while Rebar elements are used for modeling prestressing tendons. The step-by-step procedure allows the simulation of the …construction stages, effects of time-dependent deformations of materials and changes in the bridges’ structural system. Different examples of bridges, built by the balanced- cantilever method, are studied over a 30-year duration. Practical equations are modified to calculate time-dependent deflections and redistribution of internal stresses and forces in bridges constructed by the balanced-cantilever method, and good agreements between the results of the proposed method and numerical analysis are found. Significant time-dependent effects on bridge deflections and redistribution of internal forces and stresses are observed. Show more

Keywords: Creep, Segmental bridges, Box-girder, Prestress, Long-term deformations, Creep analysis, Balanced-cantilever construction, Redistribution of stresses

DOI: 10.1080/15732480701496629

Citation: Bridge Structures, vol. 3, no. 2, pp. 119-132, 2007

Authors: Zoghi, M. | Foster, D.C.

Article Type: Research Article

Abstract: Several fascia beams of an existing prestressed concrete box-girder bridge, located in the City of Defiance, Ohio, USA were severely deteriorated due to the influence of de-icing salt applied during wintertime. An in-depth visual inspection and subsequent full-scale load tests were conducted to identify the extent of deterioration. A strengthening strategy was devised involving advanced carbon fiber reinforced polymer (CFRP) composite strips, post-tensioned via the Stress Head system that was developed and patented in Switzerland. The technique, the first of its type in the USA, offers numerous advantages over conventional repair and rehabilitation methods. The inherent attributes of this innovative …approach include lighter weight for easy handling, lower loss of prestress due to higher initial tensile strain, corrosion resistance laminates, optimal use of high tensile strength of CFRP plates, optimal cost/performance ratio, and increased durability with reduction of crack width and tensile steel strain. The proprietary anchorage for prestressing the laminates, made entirely of CFRP composites, is the hallmark of this novel technique. The project, one of two bridges repaired utilizing this approach, was sponsored by the Federal Highway Administration (FHWA) through the Innovative Bridge Research and Construction (IBRC) Program. The IBRC Program promotes the use of new materials and construction techniques for the repair, rehabilitation, replacement, or new construction of bridges and other structures. The design and construction of the strengthening system, adopted to upgrade the Hopkins Street Bridge, will be presented in this paper. Show more

Keywords: Fascia beams, Box-girder, Advanced carbon fiber reinforced polymer (CFRP) composite, Post-tension, Stress Head system, Rehabilitation, Strengthening, Preservation, Laminates

DOI: 10.1080/15732480701352467

Citation: Bridge Structures, vol. 3, no. 2, pp. 133-146, 2007