A Systematic Investigation Of Shear Connections Between Full Depth Precast Panels And Precast Prestressed Bridge Girders
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| Author | : Robert Wayne Brey |
| Publisher | : |
| Total Pages | : |
| Release | : 2010 |
| Genre | : |
| ISBN | : |
Full-depth precast panels are used in concrete bridges to provide several benefits such as faster construction, lower cost and reduced constructional hazard. However, one construction drawback is that connectors are required to transmit horizontal shear across the interface between the girder and deck. Shear connector performance is characterized by a series of experiments performed on part of a bridge system that mimics a full-depth precast deck on concrete girder with a pocket-connector-haunch system. Following initial breakaway of the adhesive bond within the haunch region, the specimens slide with frictional resistance provided by the clamping force of the anchor bolt. This leads to bolt yield with an observed sliding friction coefficient of 0.8 (+/- 20%) with lower values occurring at higher displacements. It is concluded that for a viable connector system to be developed a key feature is to have sufficient stirrups in the neighborhood of the anchor bolt to form a non-contact splice and to ensure the high pull-out force can be sustained without leading to premature beam failure. The successful implementation of a full-depth precast deck-panel system requires the use of a viable design methodology that properly accounts for system behavior. The design of a deck-haunch-girder system uses a truss modeling approach to design for the shear forces created by service loading. The truss model approach is considered more suitable for a concrete member due to the premise that the member will be substantially cracked at an ultimate limit state and that traditional beam theory does not account for the decreased ability of shear stresses to transfer across open cracks. Experimental results from Chapter II, such as the friction coefficient mu, are used along with a previously developed crack angle model to layout the geometry of the truss within a deck-panel span. Design solutions are presented utilizing the Rock Creek Bridge in Parker County, Texas as an example structure.
| Author | : Sean Robert Sullivan |
| Publisher | : |
| Total Pages | : 81 |
| Release | : 2008 |
| Genre | : Bridges |
| ISBN | : |
A bridge with precast bridge deck panels was built at the Virginia Tech Structures Laboratory to examine constructibility issues, creep and shrinkage behavior, and strength and fatigue performance of transverse joints, different types of shear connectors, and different shear pocket spacings. The bridge consisted of two AASHTO type II girders, 40 ft long and simply supported, and five precast bridge deck panels. Two of the transverse joints were epoxied male-female joints and the other two transverse joints were grouted female-female joints. Two different pocket spacings were studied: 4 ft pocket spacing and 2 ft pocket spacing. Two different shear connector types were studied: hooked reinforcing bars and a new shear stud detail that can be used with concrete girders. The construction process was well documented. The changes in strain in the girders and deck were examined and compared to a finite element model to examine the effects of differential creep and shrinkage. After the finite element model verification study, the model was used to predict the long term stresses in the deck and determine if the initial level of post-tensioning was adequate to keep the transverse joints in compression throughout the estimated service life of the bridge. Cyclic loading tests and flexural strength tests were performed to examine performance of the different pocket spacings, shear connector types and transverse joint configurations. A finite element study examined the performance of the AASHTO LRFD shear friction equation for the design of the horizontal shear connectors. The initial level of post-tensioning in the bridge was adequate to keep the transverse joints in compression throughout the service life of the bridge. Both types of pocket spacings and shear connectors performed exceptionally well. The AASHTO LRFD shear friction equation was shown to be applicable to deck panel systems and was conservative for determining the number of shear connectors required in each pocket. A recommended design and detailing procedure was developed for the shear connectors and shear pockets.
| Author | : Sameh S. Badie |
| Publisher | : Transportation Research Board |
| Total Pages | : 119 |
| Release | : 2008 |
| Genre | : Bridges, Concrete |
| ISBN | : 0309099145 |
| Author | : |
| Publisher | : |
| Total Pages | : 75 |
| Release | : 2007 |
| Genre | : Bridges |
| ISBN | : |
Precast bridge deck panels can be used in place of a cast-in-place concrete deck to reduce bridge closure times for deck replacements or new bridge construction. The panels are prefabricated at a precasting plant providing optimal casting and curing conditions, which should result in highly durable decks. Precast panels can be either full-depth or partial-depth. Partial-depth panels act as a stay-in-place form for a cast-in-place concrete topping. This study investigated only the behavior of full-depth precast panels. The research described in this report had two primary objectives. The first was to develop a performance specification for the grout that fills the haunch between the top of the beam and the bottom of the deck panel, as well as the horizontal shear connector pockets and the panel-to-panel joints. Tests were performed using standard or modified ASTM tests to determine basic material properties on eight types of grout. The grouts were also used in tests that approximated the conditions in a deck panel system. Based on these tests, requirements for shrinkage, compressive strength, and flow were established for the grouts. It was more difficult to establish a test method and an acceptable performance level for adhesion, an important property for the strength and durability of the deck panel system. The second objective was to quantify the horizontal shear strength of the connection between the deck panel and the beam prestressed concrete beams. This portion of the research also investigated innovative methods of creating the connection. Push-off tests were conducted using several types of grout and a variety of connections. These tests were used to develop equations for the horizontal shear strength of the details. Two promising alternate connections, the hidden pocket detail and the shear stud detail, were tested for constructibility and strength. The final outcome of this study a set of recommendations for the design, detailing, and construction of the connection between full-depth precast deck panels and prestressed concrete I-beams. If designed and constructed properly, the deck panel system is an excellent option when rapid bridge deck construction or replacement is required.
| Author | : John Robert Kintz |
| Publisher | : |
| Total Pages | : 252 |
| Release | : 2017 |
| Genre | : |
| ISBN | : |
Horizontally curved girder bridges are often utilized for highway interchanges and other projects with restricted right-of-way. The large torsional demands caused by the girder geometry often require these systems to have extensive bracing, typically in the form of cross frames or diaphragms, to increase the torsional stiffness of the girder system during the construction phase. The most critical stage for the bracing is during the deck placement, when the noncomposite girders must resist the full construction load. Partial depth precast concrete panels (PCPs) are prestressed concrete panels used primarily as stay-in-place (SIP) formwork for straight girder systems. They are placed on full-length extruded bedding strips epoxied to the girder top flange, and the remaining depth of the deck is cast above. This is a time-efficient method of construction, and has become an attractive option due to ease of constructability and deck longevity. Although the panels have not been used on horizontally curved girder systems, there is a desire by bridge owners and contractors to use the forms in some curved girder applications. In addition to using the panels on curved girder applications, engaging the in-plane shear stiffness of the panels may lead to significant bracing in both straight and horizontally curved girder applications. A research investigation focused on measuring the behavior of PCPs acting as a shear diaphragm, as well as to develop an adequate connection between the PCPs and the girders was conducted at The University of Texas at Austin. Four PCP connection details were developed and tested at two different bedding strip heights. These connections were designed for a range of capacities, and in-plane shear load was applied until failure using a frame mechanism assembly. The experimental results showed that the connected PCPs had significant shear stiffness and strength, with the panels reaching shear capacities between 91 and 154 kips before failure depending on the connection detail that was utilized. A 46 to 70 percent increase in shear stiffness was also observed when the bedding strip height was reduced from 4 inches to 1⁄2 inch. All panels greatly exceeded the design capacity using the ACI design predictions, with 7 of 8 panels eventually failing due to concrete side face breakout. The eighth PCP failed from weld rupture in which the weld connecting the WT and the girder flange began to unzip.
| Author | : Robert J. Frosch |
| Publisher | : Purdue University Press |
| Total Pages | : 270 |
| Release | : 2009-11-01 |
| Genre | : Transportation |
| ISBN | : 9781622600809 |
This research evaluates the use of precast, prestressed bridge deck panels on new and existing precast, prestressed concrete girders. The evaluation focuses on the ease of construction and the ability of the system to develop composite action with the concrete girders. A system developed by the Connecticut Department of Transportation (CDOT) and Precast/Prestressed Concrete Institute New England Region (PCINER) was chosen for testing from available systems because it is representative of the current geometry of precast bridge deck panels. The CDOT system was evaluated in a series of large scale tests in which the panels were placed on a 40 ft prestressed concrete girder and subjected to three point loading. The CDOT system is compared to a new system developed as part of the research program. The new system addresses durability and ease of construction issues that are problematic with current joint details. The strength and geometry of both the current and new joint details are evaluated and compared in a series of direct shear tests. A final, large scale specimen was designed, constructed, and loaded to evaluate the new system. It was concluded that the behavior of the new system is comparable to that of the CDOT system. In addition, the new system is easy to construct and minimizes deck penetrations, thereby enhancing durability. This research has the potential to impact the way in which the aging highway system is rehabilitated and replaced by reducing the associated time and costs of construction while decreasing disruption to the traveling public.
| Author | : Raed Tawadrous |
| Publisher | : |
| Total Pages | : 0 |
| Release | : 2017 |
| Genre | : Bridges |
| ISBN | : 9781369834918 |
The main objective of this research is to develop procedures/criteria for designing HSS-formed shear pockets with clustered shear connectors for full-depth precast concrete deck systems. These procedures/criteria will assist in sizing shear connectors, selecting shear pocket dimensions and HSS thickness, and determining pocket anchorage and reinforcement necessary to maximize the connection capacity while allowing adequate construction tolerance. Experimental investigation (push-off testing) and finite element analysis (FEA) were performed to validate the developed design procedures/criteria. Analysis and testing results validated the adequacy of the developed design procedures/criteria for HSS-formed shear pocket connections. In addition, the results of 162 push-off tests conducted by the author and others obtained from the literature were used to check the feasibility of using current interface shear prediction models provided by AASHTO LRFD, fib MC 2010, Eurocode-2, and CSA-S6 design codes. Comparisons indicated that existing code provisions are applicable for predicting interface shear resistance of clustered shear connectors with different levels of accuracy.
| Author | : |
| Publisher | : |
| Total Pages | : |
| Release | : 2007 |
| Genre | : Precast concrete |
| ISBN | : |
| Author | : Alex Tyler Katz |
| Publisher | : |
| Total Pages | : 500 |
| Release | : 2016 |
| Genre | : |
| ISBN | : |
The majority of precast, pretensioned concrete elements are currently fabricated using 0.5- or 0.6-in. diameter prestressing strands. However, in recent years, potential benefits such as reduced fabrication costs and extended span capabilities have led to an interest in using larger-diameter 0.7-in. strands in the pretensioning industry. Such an increase in the diameter of strands might impact the shear strength of pretensioned girders due to the possibility of atypical failure modes that are not considered in current design provisions. An experimental program was conducted to study the effects of using 0.7-in. prestressing strands on the performance of precast, prestressed concrete I-girders under shear-critical loading conditions. Four full-scale pretensioned Texas bulb-tee girders (Tx-girders) employing 0.7-in. strands were fabricated and tested at Ferguson Structural Engineering Laboratory at the University of Texas at Austin. The mild steel reinforcement in the specimens was detailed according to standard drawings by the Texas Department of Transportation for girders employing 0.6-in. strands. The test program investigated the shear failure in girders with different concrete release strengths, overall member depths, shear span-to-depth ratios, and strand patterns. Analysis of the results revealed clear signs of atypical shear failure mechanisms in all specimens. Considerable strand slip was recorded at both ends of the specimens prior to peak load. In three of the specimens, the shear failure resulted in prominent horizontal cracks at the interface between the web and the bottom flange. However, all specimens demonstrated significant diagonal cracking prior to failure. Yielding of the stirrups was also confirmed in all specimens, indicating a shear-tension failure. The capacities of all specimens were conservatively estimated using the general procedure in AASHTO LRFD Bridge Design Specifications and the detailed method in ACI 318-14. The findings of this study reveal no concerns regarding the performance of existing design provisions in predicting the shear strength of Tx-girders that employ 0.7-in. diameter prestressing strands.
| Author | : Mohsen A. Issa |
| Publisher | : |
| Total Pages | : 278 |
| Release | : 2002 |
| Genre | : Concrete bridges |
| ISBN | : |
A literature review concerning the objectives of the project was completed. A significant number of published papers, reports, etc., were examined to determine the effectiveness of full depth precast panels for bridge deck replacement. A detailed description of the experimental methodology was developed which includes design and fabrication of the panels and assembly of the bridge. The design and construction process was carried out in cooperation with the project Technical Review Panel. The major components of the bridge deck system were investigated. This includes the transverse joints and the different materials within the joint as well as composite action. The materials investigated within the joint were polymer concrete, non-shrink grout, and set-45 for the transverse joint. The transverse joints were subjected to direct shear tests, direct tension tests, and flexure tests. These tests exhibited the excellent behavior of the system in terms of strength and failure modes. Shear key tests were also conducted. The shear connection study focused on investigating the composite behavior of the system based on varying the number of shear studs within a respective pocket as well as varying the number of pockets within a respective panel. The results indicated that this shear connection is extremely efficient in rendering the system under full composite action. Finite element analysis was conducted to determine the behavior of the shear connection prior to initiation of the actual full scale tests. In addition, finite element analysis was also performed with respect to the transverse joint tests in an effort to determine the behavior of the joints prior to actual testing. The most significant phase of the project was testing a full-scale model. The bridge was assembled in accordance with the procedures developed as part of the study on full-depth precast panels and the results obtained through this research. The system proved its effectiveness in withstanding the applied loading that exceeded eight times the truck loading in addition to the maximum negative and positive moment application. Only hairline cracking was observed in the deck at the maximum applied load. Of most significance was the fact that full composite action was achieved between the precast panels and the steel supporting system, and the exceptional performance of the transverse joint between adjacent panels.
