Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
S U M M A R Y Highway construction projects have considerable impact on the public. The most obvious consequences are longer travel times and an increased risk of traffic collisions. Cast-in-place (CIP) bridge deck slabs represent a significant part of construction and rehabilitation sched- ules for stringer-type bridge superstructures because much of the construction time is con- sumed in forming, placing, and tying the steel reinforcement, as well as placing and curing the CIP concrete. To shorten the construction time, full-depth precast concrete deck panel systems have increasingly been used to replace CIP decks. Full-depth precast panel systems have many other advantages in addition to shorter con- struction times, including high-quality plant production under tight tolerances, low perme- ability, less variation in volume caused by shrinkage and temperature changes during initial curing, and lower maintenance costs. Full-depth precast panel systems with no overlays or longitudinal posttensioning are particularly attractive for two reasons. First, eliminating overlays helps get the bridge opened to traffic faster, especially on a deck replacement project, because CIP concrete is needed only at the joints between the prefabricated panels. Rapid-set concrete mixes, which do not require skilled concrete placement and finishing workers, can be used for those joints. Second, eliminating field posttensioning shortens the construction schedule, lowers the cost of the deck, and simplifies the process of partial deck placement and replacement. The objectives of this project were to develop (a) recommended guidelines for the design, fabrication, and construction of full-depth precast concrete bridge deck panel systems with- out the use of posttensioning or overlays and (b) connection details for new deck panel systems. To achieve those objectives, the researchers ⢠Conducted a comprehensive literature review, ⢠Conducted a national survey of highway and design engineers, ⢠Developed new details for panel-to-panel and panel-to-superstructure joints, and ⢠Conducted an experimental and analytical investigation to validate these new connection details. The outcomes of the research can be summarized as follows: 1. Comprehensive literature review: Information on bridge projects built with full-depth pre- cast concrete panel systems was collected, reviewed, and summarized. For each project, the summary provides information on grouting materials, shear key details, panel-to-panel connections, panel-to-superstructure connections, design, reinforcement details, fabrication, installation of the deck panel system, and other critical issues. Full-Depth Precast Concrete Bridge Deck Panel Systems 1
22. Summary of results of the national survey: The national survey helped the researchers docu- ment specifications and policies developed by highway agencies that have used full-depth pre- cast panel systems. The material collected from the national survey was instrumental in developing the language for the guidelines and the load and resistance factor design (LRFD) specifications. 3. Guidelines: Recommended guidelines were developed for design, detailing, fabrication, in- stallation, and construction. The guidelines were developed to promote the use of full-depth precast panel systems among design engineers and highway agencies. 4. LRFD bridge design specifications language: Proposed LRFD specifications were developed for design, fabrication, installation, and construction. These proposed specifications are intended to replace Article 9.7.5 of the 3rd edition of the AASHTO LRFD Bridge Design Specifications. 5. New connection details: ⢠Panel-to-panel connection details: Two panel-to-panel connection details were developed that allowed the longitudinal reinforcing bars to be spliced and the bar yield strength to be fully developed, while minimizing the required embedment length. This was achieved using a new confinement technique. ⢠Panel to concrete girder connection detail: A new panel to concrete girder connection detail was developed using a cluster of three 11â4 in. (31.8 mm) studs embedded in the top flange of the concrete girder. The new detail solves the mismatching problem currently encoun- tered between the vertical shear reinforcement of the girder and the shear pockets of the pre- cast panels. ⢠Panel to steel girder connection detail: A new panel to steel girder connection detail was developed using 11â4 in. (31.8 mm) studs. The studs are clustered in groups spaced 48 in. (1220 mm) apart. The proposed 48 in. (1220 mm) spacing between clusters exceeds the 24 in. (610 mm) limit in the LRFD specifications. 6. New full-depth precast concrete deck systems: The new connection details were used to develop two full-depth precast concrete deck systems. The first system is transversely pretensioned, and the second system is transversely conventionally reinforced. Neither system uses overlays or lon- gitudinal posttensioning. These systems can be used for new construction projects or deck replacement projects. Step-by-step design calculations were developed for the first system to educate design engineers on how to best handle issues they may encounter when using full- depth precast concrete deck panel systems. 7. Experimental and analytical investigation of the new connection details and full-depth precast concrete deck systems: A comprehensive experimental and analytical study was conducted to validate and check the structural behavior of the new connection details and full-depth pre- cast concrete deck systems.
