Deck System Research Articles

Large-Diameter Shear Connector Systems for Full-Depth Precast Overhang Panels: Evaluation and Design

Accelerated bridge construction (ABC) is increasingly being used to replace aged and deteriorated bridge structures. Recently, a full-depth precast overhang deck system was developed for ABC projects. This system was reported to minimize construction time, enhance constructibility, ensure structural integrity, and improve safety during the construction process. Although the system was reported to exhibit significant benefits, standardized design methodologies were not fully developed to reliably estimate the shear capacity of the shear connector/coupler system in these precast overhang panels. Required shear capacity should be achieved for the composite action of the precast deck and girders in service. Therefore, the objective of this study is to develop design equations that can reliably predict the shear capacity of shear connectors placed between the girders and deck for composite action. Developing a reliable equation will minimize the number of shear pockets required per panel, thereby improving constructibility and reducing costs. This research investigated the use of 1.25 in. (32 mm) diameter shear connectors with different confinement systems. The two types of confinement systems included conventional reinforcing bar and high-strength steel tubes. The reinforcing bar confinement system consisted of extra steel reinforcement being embedded in the precast panel around the shear pocket and reinforcement hoops being placed within the pocket around the connector (referred to herein as inner and outer confining reinforcement). The steel tube was embedded in the precast overhang panel and defined the outside edge of the shear pocket. A total of nine specimens were subjected to shear loadings. Results indicate that the steel tube confinement system effectively increases the shear-transfer capacity for large-diameter shear connector systems. A new design equation is presented for determining the shear capacity of connector systems for precast panels.

Performance assessment of steel–concrete composite bridges with subsurface deck deterioration

In-service composite steel girder bridges typically experience a variety of deterioration mechanisms during their service lives, ranging from cracking, spalls, and delaminations in the reinforced concrete deck to corrosion in the steel girders. To date, several inspection techniques and novel technologies have been widely implemented to identify and measure different sources of defects associated with bridge systems, especially within the concrete deck. Despite successful implementation of these evaluation methodologies, what transportation agencies still lack is a fundamental understanding of the system-level behavior and the potential impact of the identified deterioration conditions on the overall performance of these bridges.In this paper, the impact of corrosion-induced subsurface deck delamination on the overall behavior and performance of steel–concrete composite bridges is investigated using finite element simulation and analysis. The accuracy and validity of the modeling approaches were assessed through a comparison to experimental data available in literature. A sensitivity study was performed to investigate the influence of deck deterioration on the system-level performance, load distribution behavior, and failure characteristics of two representative composite steel girder bridges. One of the selected structures is a full-scale laboratory bridge model, while the other one is an actual in-service structure with geometrical characteristics that represents typical features of steel girder bridges in Virginia.The selected damage scenarios included variations in different geometrical characteristics such as location and depth of damage, as well as degradation in material properties at the corresponding damaged areas. In addition to the bridge system behavior, the impact of rebar corrosion and subsurface delamination on the behavior of individual deck systems was investigated; while its implication on the current design methodologies for reinforced concrete decks was evaluated. Results from this investigation demonstrate that the deck deterioration has minimal impact on the overall system behavior and the path to failure of the selected structures, but may impact the failure characteristics in the form of reductions in the ultimate load-carrying capacity and system ductility.

Proposed revisions to fatigue provisions of orthotropic steel deck systems for long span cable bridges

Long span cable bridges, especially cable-stayed bridges or suspension bridges having record-breaking span length, have been constructed using orthotropic steel deck systems, because of light self-weight of the steel superstructure. In addition to extended span length, the bridges are requested to serve for a longer time, e.g., 200 years, which makes the bridges experience high cycle loadings and fatigue become a governing design factor. This paper summarizes research results obtained from computational analyses and experiments using 2-dimensional as well as 3-dimensional structural models. Based on the results, revisions to Korean design manual for cable-stayed and suspension bridges including new Korean models of fatigue strength curves and standard configuration of connection details are proposed in order to enhance fatigue resistance of the orthotropic steel deck systems serving for a prolonged design life.

Patch loading in slender and high depth steel panels: FEM–DOE analyses and bridge launching application

This paper studies the optimum way to design both type and position of the stiffeners when a steel bridge is assembled by means of the new protect-patented launching method based on a self-supporting deck system. This procedure is able to launch bridge up to a span of 150m, in an economical and sustainable way. The main objective of this research paper is to numerically analyze the best stiffener combination and distribution along the length of bridge, both longitudinally and transversally, in order to avoid the patch-loading phenomenon in the slender webs. An optimum design of a triangular cell along the lower plate is also presented. Thus the best stiffener distribution along the deck can be achieved to solve the two most important factors during the launching of a steel bridge: the huge forces on the support section – higher than the serviceability limit state – and buckling instability due to the point loads on the bearings. In this way, a three dimensional finite element model (FEM) is built and the design of experiments technique (DOE) is applied to obtain the best stiffener configuration. The numerical simulation allows the exact definition of the response of the structure to be achieved, covering the gaps and limits which are common in some national and international codes. Very good results have been obtained, in terms of deflection, patch loading resistance and vertical load distribution on the support section. Finally, the most important conclusions of this work are given.

Reliability-Based Condition Assessment of an Externally Restrained Bridge Deck System Considering Uncertainties in Key Design Parameters

AbstractThe objective of this research is to evaluate the reliability of bridge decks that use nonconventional materials or structural forms such as externally restrained deck systems where the available deterioration models developed for conventional systems are not applicable. The method developed here adopts the reliability theory and establishes a deterioration model for such bridge decks based on their failure mechanisms. The externally restrained deck is an innovative structural system introduced about a decade ago to the construction industry and provides corrosion-free replacement for conventional reinforced concrete decks. Because there is no established deterioration model available for these innovative systems, it is difficult to predict the reliability of such bridge decks at different instances of time. The developed method has been applied to an innovative structure with an externally restrained deck system, namely the Crowchild Trail Bridge, in Calgary, Canada, as a case study. A finite-ele...

Experimental Characterization of Ultrahigh-Performance Concrete Bridge Deck System

A lightweight, low-profile ultrahigh-performance concrete (UHPC) deck system reinforced with high-strength steel (HSS) has been proposed by the authors as an alternative to open grid steel deck. The system consists of a thin slab with primary ribs spanning between girders and shallower secondary ribs, parallel to the girders, connecting the primary ribs together. Earlier studies have shown the constructability of the deck. This paper presents system development of the deck, its connections to girders and adjacent deck panels, its response to repeated loading, and its lateral distribution of live loads. The deck-to-girder connection was made as cast-in-place UHPC around welded shear connectors and was designed to resist the shear from braking forces and the uplift from wind loads. The deck-to-deck connection was made as tongue and groove to transfer the load from one panel to the other as vehicles move on the bridge. The experiments presented in this paper confirm the feasibility of the proposed deck because the panels and their connections successfully endured 2 million cycles of repeated loading with a residual strength of at least 47% higher than the target load. Further studies are needed (1) to optimize the design by further decreasing the weight of the deck, (2) to assess the effectiveness of the UHPC as wearing surface, and (3) to monitor field performance of the deck under ambient traffic and designated truck load.

Mechanical behavior of steel-concrete composite decks with perfobond shear connectors

Exodermic deck systems are new composite steel grid deck systems which have been used in various projects during the past decade. One of the eminent features of this system is considerable reduction in the structure weight compared to the ordinary reinforced concrete decks and also reduction in construction time by using precast Exodermic decks. In this study, dynamic properties of the Exodermic deck bridges with alternative perfobond shear connectors are investigated experimentally. In order to evaluate the dynamic properties of the decks, peak picking and Nyquist circle fit methods are employed. Frequencies obtained experimentally are in good agreement with the results of the finite-element solution, and the experimental results show that the first mode is the most effective mode among the obtained modes. The first four modes are the rigid translational motion modes, and the next two modes seem to be rigid rotational motion modes around a horizontal axis. From the 7th mode onwards, modes are flexible. The range of damping ratios is about 0.5%. Furthermore, the static behavior of the Exodermic decks under a static load applied at the center of the decks was investigated. Failure of the decks under positive bending was punching-shear. The bending strength of the decks under negative bending was about 50 percent of their strength under positive bending. In addition, the weight of an Exodermic deck is about 40% of that of an equivalent reinforced concrete slab.

Field Performance of a New Fiber-Reinforced Polymer Deck

The field performance of a new bridge deck system composed of pultruded trapezoidal fiber-reinforced polymer (FRP) tubes wrapped in an outer wrap is described in this paper. The proof of concept FRP deck was installed on a rehabilitated bridge in Bolivar, New York, in 2012 as part of the Highways for LIFE Program from the Federal Highway Administration (FHWA). Based on the field test, the writers developed a three-dimensional finite-element model of the bridge superstructure to further study the interaction of the FRP deck and girders. Experimental and analytical data was used to determine that no composite action was developed by the new deck-girder connection. Comparisons between distribution factors based on field measurements and standard specifications show that the lever rule should be used to estimate live load distribution in similar bridge girder spacing. The serviceability performance of the bridge was found adequate; girder deflections met standard limits, and while the FRP deck experienced deflections larger than typically allowed, they were confined to the localized area of the wheel load and would not affect bridge users.

Characterization of Information Automation on the Flight Deck

This paper summarizes the results of analyses to identify characteristics of flight deck information automation systems which can lead to potential human factors issues. Information automation systems are responsible for the collection, processing, analysis, and presentation of information to the flightcrew. Information automation systems can pose human factors issues and challenges particular to this type of automation. This paper presents a formal definition of information automation and identifies characteristics and associated human factors issues in the domain of aircraft flight deck systems. A method was developed to identify a set of consistent and independent characteristics of information automation. Characteristics, a set of properties or attributes which describe its operation or behavior, can be used to identify and assess potential human factors issues. This effort lays the groundwork for providing data to support the development of recommendations specific to different characteristics of information automation.

Wind loads on a moving vehicle-bridge deck system by wind-tunnel model test

Wind-vehicle-bridge (WVB) interaction can be regarded as a coupled vibration system. Aerodynamic forces and moment on vehicles and bridge decks play an important role in the vibration analysis of the coupled WVB system. High-speed vehicle motion has certain effects on the aerodynamic characteristics of a vehicle-bridge system under crosswinds, but it is not taken into account in most previous studies. In this study, a new testing system with a moving vehicle model was developed to directly measure the aerodynamic forces and moment on the vehicle and bridge deck when the vehicle model moved on the bridge deck under crosswinds in a large wind tunnel. The testing system, with a total length of 18.0 m, consisted of three main parts: vehicle-bridge model system, motion system and signal measuring system. The wind speed, vehicle speed, test objects and relative position of the vehicle to the bridge deck could be easily altered for different test cases. The aerodynamic forces and moment on the moving vehicle and bridge deck were measured utilizing the new testing system. The effects of the vehicle speed, wind yaw angle, rail track position and vehicle type on the aerodynamic characteristics of the vehicle and bridge deck were investigated. In addition, a data processing method was proposed according to the characteristics of the dynamic testing signals to determine the variations of aerodynamic forces and moment on the moving vehicle and bridge deck. Three-car and single-car models were employed as the moving rail vehicle model and road vehicle model, respectively. The results indicate that the drag and lift coefficients of the vehicle tend to increase with the increase of the vehicle speed and the decrease of the resultant wind yaw angle and that the vehicle speed has more significant effect on the aerodynamic coefficients of the single-car model than on those of the three-car model. This study also reveals that the aerodynamic coefficients of the vehicle and bridge deck are strongly influenced by the rail track positions, while the aerodynamic coefficients of the bridge deck are insensitive to the vehicle speed or resultant wind yaw angle.

격자형 강합성 바닥판 이음부의 하중전달 거동에 관한 실험적 연구

The joint of prefabricated steel grid composite deck is composed of concrete shear key and high-tension bolts. The flexural and shear strength of the joint were experimentally evaluated only by the bending and push-out test of the joint element. In this study the lateral load transfer behavior of the joint in deck structure system is experimentally evaluated. Several decks connected by the joint are prefabricated and loaded centrically and eccentrically. In the case of centrically loaded specimens, the analysis results show that for the same loading step the rotation angle of the joint with 4 high-tension bolts is larger than the case of the joint with 9 high-tension bolts. Consequently, flexural stiffness of deck and lateral load transfer decrease in the case of specimen with 4 high-tension bolts. But, in the case of eccentrically loaded specimens, it is found that there are no significant differences in the load transfer behavior. The further analysis results about the structural behavior of the joint show that lateral load transfer can be restricted by the load bearing capacity of the joint as well as punching shear strength of the slab. Furthermore, considering that high-tension bolts in the joint didn`t reach to the yielding condition until the punching shear failure, increase in the number of high-tension bolts from 4 to 9 has a greater effect on the flexural stiffness of the joint and deck system than the strength of them.

Research Status of FRP-Concrete Composite Beam/Bridge Deck Systems

Fiber reinforced polymer (FRP) has widely used in civil engineering due to their high strength-to-weight, high stiffness-to-weight ratios, and corrosion resistance. To solve the corrosion of the reinforcing steel in the bridge engineering and reduce the initial cost, FRP-concrete composite structure has been considered as the most effective composite form. A detailed research status survey of FRP-concrete composite beam/deck systems and their construction applications in civil engineering is presented. Several problems in future research are put forward.

A novel connection for fibre reinforced polymer bridge decks: Conceptual design and experimental investigation

In the past two decades, the use of fibre reinforced polymer (FRP) decks has attracted a great deal of attention when it comes to the refurbishment of existing bridges and the construction of new ones. FRP materials offer superior properties, such as high specific strength and stiffness, light weight, high fatigue and corrosion resistance and good durability. Because of their low self-weight and prefabrication potential, FRP composites lend themselves to accelerated bridge construction, thereby leading to minimised traffic interference. However, one challenge that is posed by FRP deck systems is the detailing and design of panel level connections. Today, a common practice for joining deck panels on site is adhesive bonding, which compromises the benefit of rapid FRP deck installation due to the time-restricted curing required for structural adhesives. As a result, there is a need for the development of joints which enable more rapid assembly. In this paper, a novel joint configuration for panel level connections is proposed. Numerical analyses and static experimental tests were conducted to evaluate the behaviour and load-carrying capacity of the connection. The overall investigation showed that the presented joint concept is a potential alternative for panel level connections in FRP decks.

Airborne Measurement System During Validation of Egnos/Gnss Essential Parameters in Landing

Abstract The air transport requires certificate of ground and deck devices, systems and adequate procedures. However applied geodetic techniques and measuring technologies depend on taken undertakings. If one should precisely put standard ground systems and the navigational assistance are overbalancing static geodetic techniques and measuring technologies. However operational activity, depending on the phase of the flight a real requires applying geodetic techniques and measuring Jechnologies time”. As part of conducted air tests they made the validation of four fundamental parameters (accuracy, credibility, availability, continuity) of satellite EGNOS, GNSS signals, made as part of European projects: “Support to the EGNOS APV Operational Implementation - APV MIELEC”, air tests enabled to draw right procedures up and to apply satellite signals in the air transport. Details will be presented in the following article.

Study on the Static Load Test of Bridge Inspection

This practice mainly according to different position arrangement of bridge load vehicles (load test), then test the loading vehicle structure under the action of deformation and strain distribution in the cross section of the bridge deck system control parameters, such as through data and theoretical analysis, the test evaluates the performance of the bridge structure.

Steel Strap으로 횡보강된 콘크리트 바닥판의 매개변수해석을 통한 설계식 제안

Cheol-Hwan Kim Seong-Tae Yi Byung-Wan JoAbstractA deterioration of typical reinforced concrete (RC) bridge deck is due to the use of calcium chloride, cracks and water penetration inside of the deck slab with steel reinforcement. In order to eliminate the defects of RC decks in terms of material,therefore, the steel-strapped deck system is studied and developed by maximizing the arching effect while the girders are restrainedusing straps in lateral direction to the bridge. This parametric study was performed to analyze the structural characteristics of steel-strapped deck, and to identify the factors of the thickness, span length and lateral restraint stiffness of deck slab considering the concrete non-linearity. Finally, a design equation, which is adequate to South Korea, is suggested.Keywords : Lateral restraint, Concrete deck, Parametric study, Design equation, Reinforced concrete

New launching method for steel bridges based on a self-supporting deck system: FEM and DOE analyses

This paper studies a new launching method for steel bridges based on a self-supporting deck system. This new and patent-protected procedure is able to launch bridges of a span length up to 150 m, in an economical and sustainable way. The use of the last span segments to reinforce the critical sections during launching replaces other conventional temporary means applied nowadays. The main objective of this research paper is to numerically analyse the best double deck configuration as well as to define an approach to stiffener distribution in order to avoid the patch loading phenomenon in the slender webs. With this in mind, the pre-design of a triangular cell along the low flange of each web is presented. A three dimensional finite element model (FEM) is built and the design of experiments technique (DOE) is applied to obtain the best bridge configuration. This new construction method can be used together with a continuous launching system in order to increase the velocity of the whole operation and to improve safety during launching. Very good results have been obtained, in terms of deflection, patch loading resistance and vertical load on the pushing device. The comparison with other different construction systems and the application to a real case allows us to ensure the viability of the method described.

Finite-Element Modeling of Hybrid Composite Beam Bridges in Missouri

Three bridges were recently constructed in Missouri using a new type of hybrid composite beam (HCB) incorporated within traditional RC deck systems. These HCBs are comprised of three main subcomponents: a composite shell, compression reinforcement, and tension reinforcement. The compression reinforcement is a self-consolidating concrete (SCC) arch that is tied at the ends by high-strength galvanized steel strands. The compression and tension reinforcements are encapsulated in a glass fiber–reinforced polymer (GFRP) box, and the voids are filled with polyisocyrunate (polyiso) foam. This unique configuration aims to optimize the structural performance of the HCB constituents, hence optimizing the overall performance of the beam. However, because of the novelty of the HCB, its structural behavior is not yet completely understood. Consequently, the finite-element (FE) modeling of this new type of beam is crucial for providing deeper insight into its structural behavior and validating the current design assumptions. It is, therefore, the main goal of this study to examine the accuracy of linear FE analysis (FEA) in predicting the static behavior of the HCB under service loads. This paper explains in detail the FE modeling of the superstructure of one of the recently constructed HCB bridges, using two commercial FEA packages. A field load test that simulates several load cases was applied to the bridge, and the deflections of the HCBs were measured at different locations. A simple analytical procedure that is based on the transformed area method is also used to predict the HCB deflections. The comparison between measured deflections and predicted deflections shows that the FEA can predict the HCB bridge behavior with acceptable accuracy, whereas the theoretical procedure significantly overestimates the beams’ deflections. Finally, the two FE models are used to analyze the behavior of the HCBs.

A simplified structural mechanics model for cable-truss footbridges and its implications for preliminary design

Compared with traditional suspension footbridges, the cable-truss footbridge is always easier to satisfy structure deformation requirements under small dead-load-to-live-load ratio condition, and it enjoys surging popularity in western China. In this type of bridges, the deck system is designed as a pure local load-bearing member, and the inverse pre-tensioned deck cable system is set up to form a tension–tension mechanical system. To better understand its structural performance, a simplified structural mechanics model for cable-truss footbridges is proposed, and the analytical formulations for deformation and internal forces of the bridge under entire span live load as well as semi-span live load have been derived. The reliability and accuracy of the proposed model have been validated in a comparison study with the finite element analysis. Furthermore, a series of qualitative and quantitative parametric studies have been conducted, which reveal that the cable-truss bridges have several novel structural characteristics that differ from that of traditional suspension bridges. Finally, the affordability range of cable-truss bridges is also discussed by using material usage analysis.

Assessment of vehicular live load and load factors for design of short-span bridges according to the new Egyptian Code

The new Egyptian Code (ECP-201:2012) introduces new vehicular live loads (VLL) and new load combinations for the design of roadway bridges. The new VLL and load combinations introduced in ECP-201:2012 are fundamentally different than those presented in previous versions of the code. The impact of these new loads and load combinations on the design of new bridges or the structural safety of the existing bridges that have been designed according to ECP-201:2003 or ECP-201:1993 has not been fully addressed for the different bridge deck systems. Three different bridge deck systems, i.e. concrete I-shaped girders, composite steel plate girders, and concrete box-girders with different spans were numerically modeled using two-dimensional grillage analogy. The bridge decks were analyzed under main gravity loads using VLL according to ECP-201:2012 and ECP-201:2003. The internal forces of individual load cases, total un-factored load combination, and total factored load combination of ECP-201:2012 and ECP-201:2003 were compared.The study shows that concrete box-girders designed according to ECP-201:2012 and ECP-201:2003 using the ultimate limit state method yield almost the same demand. Despite the increase in the VLL of ECP-201:2012, and consequently the live load forces, concrete I-shaped girder bridges will be subjected to less total factored internal forces in comparison to ECP-201:2003 This is attributed to the interaction between the live to dead loads ratio and the load combinations. Design of composite steel plate girder bridges according to ECP-201:2012 using the allowable stress design method yields over designed sections.