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1 Public inconvenience and loss of income during bridge construction and rehabilitation have prompted exploration of rapid construction methods. In 2001, FHWA launched the Accelerated Bridge Construction (ABC) initiative. ABC is bridge construction that uses innovative planning, design, materials, and construction methods in a safe and cost- effective manner to reduce the construction time associated with maintenance of traffic when building new bridges or replacing and rehabilitating existing bridges. Cast-in-place (CIP) bridge deck slabs represent a significant part of construction of stringer-type bridge superstructures. Much of the construction time is consumed in deck forming, placement of steel bars, and placement and curing of CIP deck concrete. In addition, studies have shown that CIP decks in harsh environments where deicing chemicals are used are considered one of the major elements of highway bridges requiring frequent maintenance, including patching, sealing, and placement of overlays. CIP decks pose low durability performance because of shrinkage cracking, high permeability, and direct exposure to deicing chemicals and moisture. As a result, full-depth precast concrete deck panel systems have been increasingly used to replace CIP decks. In addition to higher construction speed, full-depth precast concrete deck panel systems have advantages such as high-quality plant production, low permeability, and much-reduced volume-change crack- ing caused by shrinkage and temperature drop during initial curing. High-quality precast concrete decks are often pretensioned in the transverse direction and post-tensioned in the longitudinal direction. They have relatively low life-cycle costs, even though they may have higher initial costs in some U.S. markets. Although full-depth precast concrete deck panel systems have many advantages compared to CIP decks, some challenges have been reported with these systems, including achieving full composite action with the supporting girders and durability of the CIP joints. The outcomes of this project address these issues. The goals of this project are as follows: 1. Develop a simplified full-depth precast concrete deck panel system with panel-to-panel and panel-to-girder connections that satisfy the following criteria: a. Provide satisfactory composite action with the supporting girders. b. Meet FHWA goals of ABC, which include minimal construction steps, duration of each step, and safety risks to construction workers. c. Can be assembled from the top of the bridge deck. d. Require simplified grouting between the precast deck panels and the supporting girders. e. Keep fabrication of the precast deck panels as simple as possible by minimizing shear pockets, minimizing top-surface construction joints, and relaxing tight tolerances. f. Make inspection easy for quality assurance during construction. g. Require minimal long-term maintenance. S U M M A R Y Simplified Full-Depth Precast Concrete Deck Panel Systems
2 Simplified Full-Depth Precast Concrete Deck Panel Systems 2. Investigate various concepts, including constructability and structural behavior of the girderâdeck system under various stages of the bridge life. 3. Investigate various design and construction issues through analytical and experimental programs, and select the proper criteria to be recommended for implementation. 4. Develop guidelines and specifications for design and construction of the recommended system. 5. Carry out proposed revisions to the AASHTO LRFD Bridge Design Specifications. The outcome of the research can be summarized as follows: 1. Comprehensive literature review: Information on bridge projects built with full-depth precast concrete panel systems were collected, reviewed, and summarized. The summary provides specific information on critical issues such as grouting material, shear key details, panel-to-panel connections, panel-to-superstructure connections, design, reinforcement details, fabrication, and installation of the deck panel system. 2. A full-depth precast concrete deck panel system, which has the following features: a. Spacing between shear connector joints that is up to 6 ft. b. A discrete joint connection system that provides for full composite behavior between the deck and the supporting girders. c. Spacing between the discrete joints at the haunch between girder top face and deck soffit that can be left unfilled. d. The ability to be used with precast concrete or steel I-girders. e. The deck can be longitudinally post-tensioned using a novel, simplified, âduct- in-ductâ system. This system uses sheathed post-tensioned strands that do not require grouting or splicing of the post-tensioned ducts at the transverse joints between panels. f. A solid deck panel, or ribbed if deck weight reduction is desirable to improve super- imposed load capacity. g. A unique collared dual rod (CDR) assembly developed and found to give excellent results for shear connection of concrete girders to the precast deck. 3. Analytical and experimental investigations of the developed full-depth precast concrete deck system. The experimental study included push-off (small-scale) specimens, as well as large-scale beams. 4. Guideline manual: Recommended guidelines for design, detailing, fabrication, installation, and construction were developed to help implement the proposed system by designers and bridge owners. 5. Proposed revisions to the AASHTO LRFD Bridge Design Specifications.
