Full-depth Precast Concrete Bridge Research Articles

Finite Element Investigation of Angle Ring Confinement for Clustered Large-size Stud Shear Connector in Full-Depth Precast Concrete Bridge Deck Panel

Full-Depth Precast Concrete (FDPC) bridge deck panel system, consisting of concrete deck and steel girders, has been used widely for highway and bridge construction due to rapid construction and replacement as well as in terms of economics. This system could integrate with clusters of large size headed-stud shear connectors for more significant connection, although larger composite actions were experienced. Therefore, a new angle steel ring confinement was introduced and tested by push-off samples for the most effective shear transfer. The Finite Element Analysis (FEA) of the push-off model with an in-depth investigation of non-linear concrete properties, boundary parameters, and different geometries of angle ring confinement was developed in this study. The FE models were verified with the push-off test in terms of loads, displacements, and failure stages. Nonlinear concrete material models: Concrete Damage (CD) and Drucker Prager (DP) were identified the different abilities either for predicting initial cracks, or determining maximum resistance and critical failure, respectively. The thickness of the angle and the sizes of hook bars were investigated for the most effective aspects of the angle ring confinement. The results showed comparable stiffness and load resistance for various aspects. However, compatible geometries, either 5 mm thick angles with DB12 hook bars or 10 mm angles with DB25 hook bars, were suggested. The final non-linear FEA model was reliable for comparative studies to FDPC push-off with different confinement configurations.

"Impact of shear connectors on composite action in full-depth precast concrete bridge systems"

This theoretical research used the finite element method to model full-depth precast concrete deck slabs. It examined the effects of pocket spacing and number of shear studs per pocket. Results indicat­ed that horizontal shear strength increases with the number of pockets in both supported and continu­ous-span models. Load–deflection curves and slippage values were recorded and compared with experimental tests, confirming that pocket spacing is an important factor and that the number of studs and their config­uration affects the load for slippage induction. The parametric study evaluated effects of shear connector sizes and various numbers of shear studs for distances of 24 and 48 in. (609.6 and 1219.2 mm) between shear pockets for simply supported bridges; however, there is a need for experimental evaluation of shear connector performance on design.

Fatigue behavior of steel ring confinement for a clustered stud shear connector in full-depth precast concrete bridge deck panel

Steel L-angle ring confinement for a cluster of large size studs was found to be the effective resistance for transferring composite actions between the full-depth precast concrete bridge deck panels and steel girders. However, the behavior of this type of confinement is still unclear under the repetitive service load condition. The research investigates fatigue behavior of L-angle steel ring with hook bars for confining a cluster of 4 large size studs (31.8 mm diameter) in the composite full-depth concrete deck system under cyclic loads. Three Push-off specimens were loaded repetitively from the hydraulic jack to observe the fatigue resistance of the deck, the studs, and the ring confinement. The load ranges and cycles of loading were based on fatigue resistance of an individual stud in according to AASHTO LRFD 2012 design specification. The cyclic service loads were performed in a range from 0 to 294 kN (30 Ton-force) in about 3,000 cycles. With initial load ranges from 0 to 98 kN (10 Ton-force) in 1,000 cycles, the fatigue shear resistance could reach higher about 100% as seen by twice number of loading cycles. The loading cycles had more influence than the load range limits in terms of service life, and vice versa in term of resistance. Visual inspections detected initial cracks at the top surface of the concrete deck nearby the jacking zone. With higher load ranges, cracks were propagated to the concrete deck bear to the shear pocket, and finally caused permanent bent out to the ring confinement. However, the splits of concrete were still in place because of hook bars welded to the ring confinement.

Effects of fillet weld to large-size stud shear connector in full-depth precast bridge deck panel

Resistance of large size headed stud shear connectors 31.8 mm (1¼″) diameter for full-depth precast concrete bridge deck panel with steel girders depends on various factors. One important factor is the weld connection between studs and a steel girder. This research presents two main welding effects: (1) beveling shape of the base stud and (2) layers of fillet weld, which could result to effective composite actions. Three groups of specimens were tested varying among three different beveling sizes, and 2 or 3-layer of fillet weld. The first group (S1-N0) contains studs without beveling, the second (S2-N5) and third (S3-N10) groups consist of studs with 5 mm and 10 mm bevel cut widths in 45-degree, respectively. Each was subjected to shear force from the hydraulic jack until failure or bending limit. The studs in S2-N5, both 2 and 3-layer of fillet weld, could obtain maximum shear resistance up to 56.8 kN (5.8 Ton-force). The large relative displacement (up to 56 mm) was carried on the studs in S1-N0 in both 2 and 3-layer of fillet weld. The stiffness (Load/displacement ratio) of the S3-N10 group were about 5% higher than those without beveling in the S1-N0 and S2-N5 group, which were about 3.56 kN/mm (0.4 Ton-force/mm). In terms of failure mode, tearing out at the bottom of the shank studs was appeared in some samples in the S2-N5 and S3-N10 groups, but in the S1-N0 group.

Experimental Investigation of Steel Confinement of Clustered Large-Size Stud Shear Connector in Full-Depth Precast Bridge Deck Panel

The research focuses on investigating different types of steel confinements around a clustered large-size stud shear connector using in full-depth precast concrete bridge deck panel. The tests were based on Push-off test of two main groups of specimens: (1) the specimens with 4-stud shear connector where three different types of confinement were adopted including of O-ring confinement, Wire-mesh confinement, and L-angle confinement), and (2) the specimens with 8-stud shear connector where two different types of confinement were investigated including of Plate-ring confinement and L-angle confinement. The test results concluded that L-angle confinement type of the group of specimens with 4-Stud is the most sufficient type comparing between the different types of confinement in the same group. The maximum resistance was found at 41-ton, while as the displacement was found to be the most expansible and gradually reduced until the failure point. This means that the sign of failure can be noticeable prior to a collapse of the structure. For the group of specimens with 8-Stud, the resistance of this group was higher than the group of specimens with 4-Stud about 50 - 100% increase depending on each type of confinement. The maximum resistance was found for Plate-ring confinement type at 70-ton, which was agreed with the increment of the displacement about 20 - 50%. In comparison between specimens with 8-Stud, the Plate-ring confinement showed greater resistance and more relative displacement about 15% than the L-angle confinement.

Behavior of Prefabricated Full-Depth Precast Concrete Bridge Deck Panel System: Optimum Prestress Level

This paper reports on results and findings obtained from a nonlinear finite element analysis (NLFEA) of a prototype prefabricated full-depth precast concrete bridge deck panel system under different level of prestressing force. The NLFEA were validated with experimental results obtained from full-scale testing of the prototype bridge system. The benefits of the NLFEA can be highly appreciated when visualizing the substantial time and cost savings, the ability to change any parameter of interest, and the capability of demonstrating any interesting response at any load value and at any location in the system. The most attractive results were: (1) the system is capable of withstanding and maintaining its integrity under eight times the simulated AASHTO truck service load without considerable reduction in its ultimate strength capacity and stiffness, (2) The NLFEA showed that the live load-induced bond stresses for 4 lines prestress level was almost 0.74 times the live load-induced bond stresses for 6 lines prestress level.

Experimental investigation of connection details for precast deck panels on concrete girders in composite deck construction

Full-depth precast concrete bridge deck panels are connected to the girders on site by shear connectors to create a composite action and to prevent relative movement between the beam and the precast deck during all loading levels. This research study experimentally investigates different connection details that can provide a load transfer mechanism between concrete girders and precast deck panels to ensure full composite action. Three connection details were investigated: unconfined studs, confined studs and rebar dowels. Six specimens were cast and tested in direct pull-out or push-off tests. The confined studs showed the highest shear capacity at low displacement levels as well as the highest pull-out capacity. However, the three configurations showed higher capacities than expected according to the Canadian highway bridge design code.

The optimum overlay thickness of prefabricated full-depth precast concrete bridge deck panel system – 3D non-linear finite element modeling

Segmental construction of prefabricated full-depth concrete bridge deck systems results in numerous transverse and longitudinal joints as well as shear connector pockets that receive cast-in-place concrete or grout. In such systems, it is necessary to overlay the bridge deck to provide smooth riding surface and to protect the underlying deck reinforcement from the deicing salts-induced corrosion and consequent spalling and delamination of the concrete.This paper reports on results and findings obtained from a non-linear finite element analysis (NLFEA) of a prototype prefabricated full-depth precast concrete bridge deck panel system before and after being overlaid with various plain and fibrous latex-modified concrete (LMC) and microsilica concrete (MSC) overlays. The NLFEA were validated with experimental results obtained from full-scale testing of the prototype bridge system. The benefits of the NLFEA can be highly appreciated when visualizing the substantial time and cost savings, the ability to change any parameter of interest, and the capability of demonstrating any interesting response at any load value and at any location in the system. The most attractive results were: (1) adequately bonded LMC or MSC overlay significantly improves the stiffness, cracking load, and ultimate strength capacity of the system, (2) AASHTO HS20 truck induced bond stresses were below the bond strength of bonded LMC and MSC overlays, (3) the fibrous overlay has desirable crack arresting characteristic.

Full-Scale Implementation and Testing of Full-Depth Precast Bridge Deck Panels

A bridge deck panel system using nonprestressed full-depth precast concrete bridge deck panels with continuous shear pockets was investigated. First, the research team performed conceptual improvement, design, detailing, and fabrication studies on a specific deck replacement system (System CD-2) previously proposed by NCHRP Project 12-65 researchers. Key improvements to the CD-2 deck panel system included modifications to the transverse joint coupler for ease of construction and the addition of a longitudinal staged-construction joint to expedite bridge deck replacement projects. Next, an experimental program was carried out to construct and perform service-level load testing on a full-size precast deck panel assemblage that incorporated the refinements. On the basis of static and cyclic loading test results, it was found that the modified CD-2 deck panel system as a whole performed satisfactorily with regard to AASHTO serviceability requirements.

Transverse panel-to-panel connections for full-depth precast concrete bridge deck panels on continuous steel girder bridges: Part 1, experimental

The focus of this article is the performance measurement of transverse panel-to-panel connections for full-depth concrete bridge deck panels on continuous steel girder bridges. Using a simulated HS 20 vehicle loading, two nonprestressed and four posttensioned connections are tested cyclically in negative bending. Testing objectives include the determination of the net service stress limit required to control cracking and prevent leaking under service load moment. Results find cracking and leaking to occur for connections with 170 psi of initial stress and no leaking or full-depth cracking for connections with 340 psi. The superior performance of the connections with higher prestress leads the authors to recommend the specification of a maximum net tensile stress of 3√fc.

Transverse panel-to-panel connections for full-depth precast concrete bridge deck panels on continuous steel girder bridges: Part 2, time-dependent analysis

In this article, the authors seek to determine the initial compressive stress to avoid cracking and leaking in precast, prestressed concrete bridge deck panels. They use an age-adjusted effective modulus method to evaluate time-dependent stress redistribution in composite systems. The evaluation found an initial precompression of 200 to 300 psi to be adequate for single span bridges, 200 to 700 psi for three-span bridges, and 100 psi for two-span bridges. They also determine that accelerated construction schedules for continuous span bridges make it necessary to substantially increase initial compressive stress.

Modified Yield Line Theory for Full-Depth Precast Concrete Bridge Deck Overhang Panels

Full-depth precast deck slab cantilevers also referred to as full-depth precast concrete bridge deck overhang panels are becoming increasingly popular in concrete bridge deck construction. To date, no simple theory is able to estimate the overhang capacity of full-depth concrete bridge deck slabs accurately. Observations suggest that interaction between flexure and shear is likely to occur as neither alone provides an accurate estimate of the load-carrying capacity. Therefore, modified yield line theory is presented in this paper, which accounts for the development length of the mild steel reinforcing to reach yield strength. Failure of the full-depth panels is influenced by the presence of the partial-depth transverse panel-to-panel seam. When applying a load on the edge of the seam, the loaded panel fails under flexure while the seam fails in shear. Through the use of the modified yield line theory coupled with a panel-to-panel shear interaction, analytical predictions are accurate within 1–6% of experimental results for critical cases.

Towards Sensor-Based Health Monitoring Systems for Bridge Decks: A Full-Depth Precast Deck Panels Case Study

Traffic and variable loading conditions greatly influence the performance, durability, and safety of a bridge structure throughout its service life. Continuous monitoring can provide the basis for determining the deterioration rate and for estimating the remaining service life, thus assisting in making important decisions regarding bridge maintenance. This paper presents the design and implementation of a health monitoring system for condition assessment of full-depth precast concrete bridge deck, which was developed for the Parkview Bridge in Kalamazoo, Michigan. This system is composed of a remotely accessible on-site data acquisition system and a sensor network of vibrating wire strain gauges to monitor strain and temperature over given time increments. The system relies on the sensor network embedded in the bridge deck to gather static performance data under different loading conditions to provide condition assessment by collecting, storing, analyzing, and reporting relevant performance data over time. The paper presents a practical case study that mainly focuses on describing the initial steps in the development of the sensor network system, namely, the design (system architecture and data structures) and construction along with examples of how the data is acquired, organized, presented, and analyzed, keeping in mind that the bridge is still early in its life-cycle and has not yet experienced any structural problems.

Full-Scale Testing of Prefabricated Full-Depth Precast Concrete Bridge Deck Panel System

The implementation of a prefabricated full-depth precast concrete deck system is an innovative technique that accelerates the rehabilitation process of a bridge deck extending its service life for the purpose of reducing user delays, and community disruptions and lowering its life-cycle costs. A full-scale, two-span continuous prototype bridge 82 ft (25 m) long and 18 ft (5.5 m) wide was designed, constructed, and tested for service load, overload, and ultimate load to study the constructibility and structural performance of the prefabricated full-depth precast concrete bridge deck system. The bridge superstructure is composed of 11 prefabricated full-depth precast concrete panels placed on three steel beams (W18 x 86) and made fully composite with shear connector pockets and shear studs. The experience gained from the sequence of construction events such as fabrication, handling and erection, grouting of transverse joints, longitudinal post-tensioning, and grouting of haunches and shear connector pockets in addition to the results derived from testing a full-scale prototype bridge indicated that a prefabricated, post-tensioned deck system is workable and constructible. Finite element analysis and experimental test results also indicated that a full composite action was maintained between the post-tensioned precast concrete panels and the supporting system; also, no cracks were observed in the transverse joints at the negative moment regions.

Behavior of Horizontal Shear Connections for Full-Depth Precast Concrete Bridge Decks on Prestressed I-Girders

This article reports on a study of the horizontal shear resistance of the connection between full-depth precast concrete bridge deck panels and prestressed concrete girders. This connection consists of isolated shear connectors extending from the precast I-girder into a block-out pocket in the precast deck panel. The blockouts and the haunch between the panel and the beam are grouted. In the study, 36 push-off tests were performed to investigate the strength and behavior of the connections. The factors investigated included type of grout, haunch height, and area of reinforcing steel crossing the interface. In addition, several alternate shear connector details were tested. Results showed that there was no significant difference in peak shear stress between specimens with 1, 2, and 3 in. haunch heights. The extended stirrups must be detailed to have a minimum of 5 in. embedment into the deck panel. The alternate shear connectors in this study are viable for use with the precast panel system. Proper embedment and spacing of connectors will ensure yielding of the steel and ductile behavior of the interface. The authors conclude that, of currently known horizontal shear resistance equations, the one presented in the AASHTO LRFD Bridge Design Specifications is the best predictor of the strength of the specimens.

Composite Behavior of Shear Connections in Full-Depth Precast Concrete Bridge Deck Panels on Steel Stringers

This study investigates the composite behavior of full-depth precast concrete bridge deck systems under static loading. Entailed is a detailed evaluation of quarter-scale and full-scale system components, with a focus on the number of pockets per specimen, number of studs per pocket, and the benefits of a grouted haunch for the connection between the precast slab and its supporting system.

Performance of Transverse Joint Grout Materials in Full-Depth Precast Concrete Bridge Deck Systems

This paper investigates the behavior of transverse joints grouted with four different grout materials in precast concrete deck systems. 36 full scale specimens were fabricated and tested for vertical shear, direct tension, and flexural capacity. The goal of the paper is to provide engineers with realistic guidelines for determining the best grout material for use under various conditions. Provided are recommendations based on the laboratory experimental results of transverse joints, finite element analysis methodology, field performance of the full depth precast concrete bridge systems and full scale testing of full depth precast, prestressed concrete slabs installed on steel stringers.

Analysis of Full Depth Precast Concrete Bridge Deck Panels

Several researchers have reported on the use of full depth precast concrete bridge deck panels for the replacement and rehabilitation of deteriorated bridge decks. They presented the advantages of the system and generally recommended viable alternatives to many aspects of the system. However, a critical aspect of the system in terms of design is the consideration of longitudinal post-tensioning. This paper presents the analysis of selected simply supported and continuous bridges using finite element modeling of the structural system. The objective of this analytical study was to determine the amount of post-tensioning needed in the longitudinal direction to secure the tightness of the adjacent transverse joints and to keep them in compression.