Deck System Research Articles

The Analysis for the Static Responses of the through Composite Truss Bridge with Simply Supportation

According to deforming properties of the structure in the action of symmetry loads and the assumption to the displacement functions of the equivalent composite box beam, the total potential energy of the structure is obtained. Based on the spline finite point method, the stiffness equations are deduced, which could be used to determine the approximate solution of the through composite truss under the action of double-lines symmetry loads in considering the relative slip between longitudinal beams and concrete slabs on the deck system, the vertical deformation of transverse beams and the shear lag effect of concrete slabs. The mechanics behavior of the thorough composite truss is studied by means of a calculated example.

Study on Influences of Thickness of Flange of U Rib on Mechanical Behaviors of Orthotropic Monolithic Steel Bridge Deck System

Orthotropic monolithic steel bridge deck system stiffened by U rib is very fit for high-speed railway steel bridges because of its excellent mechanical behaviors. Thickness of flange is a very important parameter of U rib and has influence on mechanical behaviors of orthotropic monolithic steel bridge deck system. Based on the engineering practice of Anqing Yangtze River Railway Grand Bridge, the kind and the extents of influences of thickness of flange of U rib on mechanical behaviors of orthotropic monolithic steel bridge deck system are studied with finite element analysis. The results show that thickness of flange of U rib has relative large positive influences on rigidity, strength and stability of orthotropic monolithic steel bridge deck system. 14~18mm is the appropriate range of thickness of flange of U rib for high-speed railway steel bridges.

Method to Compute Live-Load Distribution in Bridge Girders

Live-load distribution is an important step in the analysis of bridge superstructures. This paper introduces a new framework to compute live-load distribution for bridge girders. The model uses elastic spring elements to simulate the reaction of main girders to the deck system. The cross-section frame of the superstructure is supported by these elastic springs. Live-load distribution factors are derived according to the maximum reaction of each spring element under random truck loads. Results from the proposed model are compared with those from bridge-design specifications. Engineering practice shows that this model is easy to use and provides results comparable with current design standards. The significance of this framework is that it can be used to compute live-load distribution without limits to parameters such as girder space, span length, and truck-wheel space. This research will provide a convenient tool for engineers to perform bridge design or for researchers to compare research results from other methods.

Experimental Evaluation of Aluminum Bridge Deck System

Most of the movable bridges in the United States have open grid steel decks, primarily because they are factory assembled, lightweight, and easy to install. Open grid steel decks, however, are not as skid resistant as solid decks. Costly maintenance, high noise levels, poor riding comfort, and susceptibility to vibrations are among the other disadvantages of these decks. The objective of the research presented in this paper is to evaluate an alternative lightweight extruded aluminum deck system that has a solid surface and meets the loading requirements as well as weight and thickness limits for movable bridge decks. These aluminum deck panels with their tongue and groove connections have previously been used in Europe, mainly in Sweden. A detailed experimental evaluation of the aluminum deck system has been carried out, including static and fatigue load testing on the deck panels, as well as ancillary tests on the connections with the girders. On the basis of the in-depth experimental evaluation and the subsequent finite-element (FE) modeling and predictions, the extruded aluminum deck is shown to be a feasible alternative to the open grid steel deck and ready for implementation on movable bridges as well as bridges that require a lightweight deck.

Mechanism of Early Cracking and Serviceability of Precast Reinforced Concrete Bridge Deck Slabs

In the light of the mechanism of early cracking in a batch of precast reinforced concrete hollow slabs of four certain bridges in construction whose midspan appears transverse cracks, investigation ranging from method of construction to distribution of cracks are conducted in situ. The possibility of the occurrence of cracks is discussed in detail. Theoretical calculation as well as numerical analysis reveals that the main reason of formation early cracking in slabs is self-weight loading. In order to assess the performance of the bridge deck system which appears cracks and evaluate the effect of early cracking on structural behavior, numerical analysis is performed to conclude that the bridge deck is satisfied with the serviceability requirements. In view of the fact that this kind of slab is widely used in bridge projects for convenience in construction and advantage in cost, effective and economical crack control measurement and technical proposal are recommended with regard to the design, construction and amendment of design specifications.

Structural performance of composite sandwich bridge decks with hybrid GFRP–steel core

Abstract This paper presents the static and fatigue performance of composite sandwich bridge decks with hybrid GFRP–steel core. The composite sandwich bridge deck system is comprised of wrapped hybrid core of GFRP grid and multiple steel box cells with upper and lower GFRP facings. Its structural performance under static loading and fatigue loading with a nominal frequency of 5 Hz was evaluated. The responses from laboratory testing were compared with the ANSYS finite element predictions. The failure mode of the proposed composite sandwich bridge deck was more favourable because of the yielding of the steel tube when compared with that of all-GFRP decks. The ultimate failure of the composite sandwich deck panels occurs by shear of the bonded joints between GFRP facings and steel box cells. Results from fatigue load test indicated no loss in stiffness, no signs of de-bonding and no visible signs of deterioration up to 2 million load cycles. The thickness of the composite sandwich deck retaining the similar stiffness may be decreased to some extent when compared with the all-GFRP deck. This paper also presents design of a connection between composite sandwich deck and steel girder.

Component sizing approach for the sandwich plate system

The sandwich plate system (SPS) is a bridge deck system consisting of steel face plates bonded to a rigid polyurethane core. SPS bridges are typically constructed as a series of pre-fabricated SPS deck panels compositely connected with traditional steel girders. The decks are thin, lightweight and modular, and can be tailored to numerous applications including both new bridge and rehabilitated bridges. With new system, there exist hurdles in the implementation; for SPS, the primary challenge is the lack of an established design method for the panel cross-sections. Presented herein is a method for sizing SPS panel sections for bridge applications. This method is limited to the selection of steel plate and core dimensions, subjected to American Association of State Highway and Transportation Officials (AASHTO) limit states of serviceability, strength and fatigue and does not consider connections or bond aspects of the system. The sizing approach considers the deck panels as plates with variable boundary conditions subjected to the loading conditions of the AASHTO Load Resistance Factored Design (LRFD) bridge design specification. Results from this study indicate that the component sizing for SPS deck panels is controlled by stiffness and that plates selected to satisfy the AASHTO limiting deflection criterion will also be adequate for the remaining serviceability, strength and fatigue limit states.

Sustained-Load and Fatigue Performance of a Hybrid FRP-Concrete Bridge Deck System

The design and construction of bridge systems with long-term durability and low maintenance requirements is a significant challenge for bridge engineers. One possible solution to this challenge could be through the use of new materials, e.g., fiber-reinforced polymer (FRP) composites, with traditional materials that are arranged as an innovative hybrid structural system where the FRP serves as a load-carrying constituent and a protective cover for the concrete. This paper presents the results of an experimental investigation designed to evaluate the performance of a 3/4 scale hybrid FRP-concrete (HFRPC) bridge deck and composite connection under sustained and repeated (fatigue) loading. In addition, following the sustained-load and fatigue portions of the experimental study, destructive testing was performed to determine the first strength-based limit state of the hybrid deck. Results from the sustained-load and fatigue testing suggest that the HFRPC deck system might be a viable alternative to traditiona...

Probabilistic Risk Assessment of Fan Type Cable Stayed Bridges Against Earthquake Forces

A fragility analysis of a fan type cable stayed bridge using a probabilistic risk analysis (PRA) procedure is presented to determine its probability of failure under random ground motion. Seismic input to the bridge support is considered to be a band-limited white noise at the bedrock. For the response analysis, the bridge deck is modeled as a beam supported on springs at different points. The stiffnesses of the springs are determined by a separate 2D static analysis of the cable—tower—deck system. A continuum method of analysis using dynamic stiffness is used to determine the dynamic properties of the bridges.The responses of the bridge deck are obtained by the response spectrum method of analysis for multiple-degrees-of-freedom system. The fragility analysis includes uncertainties of responses due to the variation in ground motion, material properties, modeling and method of analysis. Uncertainties of the capacity of the structure are considered, such as ductility factor variation and damage concentration effects. Failure of the bridge is assumed to take place when the bridge deck moment at any section within a supported span reaches the yield value. The probability of failure of the bridge deck is determined by the first order second moment (FOSM) reliability method. A three-span double-plane symmetrical cable stayed bridge is used as an illustrative example. The fragility curves for the bridge deck failure are obtained under a number of parametric variations which include ratio of the components of ground motion, spatial correlation of ground motion, angle of incidence of earthquake, ductility ratio and coefficients of variation of the uncertainty factors. The results of the study show that these factors have considerable effect on the probability of failure of the bridge.

Flexural Lateral Load Distribution Characteristics of Sandwich Plate System Bridges: Parametric Investigation

The sandwich plate system (SPS) is a relatively new bridge deck system that consists of steel face plates bonded to a rigid polyurethane core. The decks are thin, lightweight, and modular in design and can be tailored to numerous applications. This system provides an excellent alternative for the rapid construction and rehabilitation of bridge decks. With any new system, there exists some uncertainty in the design procedures as a result of the limited population for comparison. This paper presents the results of a finite-element parametric investigation of the lateral load distribution characteristics of SPS bridges. The parametric study primarily focuses on the influence of deck thickness on distribution behavior as compared to conventional reinforced concrete decks. Results from the study demonstrate that the inherent flexibility of a thin SPS deck yields larger distribution factors (up to 20%) than a typical reinforced concrete deck, but these distribution factors can still be conservatively estimated with current AASHTO LRFD methods. Additional comparisons indicate that the distribution behavior of SPS bridges can also be estimated with the equations proposed by the NCHRP 12-62 project.

Composite concrete/GFRP slabs for footbridge deck systems

In recent years the use of advanced composite materials has gained wider space in the civil engineering sector, due to some favorable characteristics such as lightweight, high specific strength, resistance to corrosion and fatigue. Innovative systems that combine concrete with advanced composite materials have proved to be a viable and efficient solution as compared to conventional systems. In this work, a new slab system composed of a fiber-reinforced concrete top laid on glass fiber reinforced polymeric (GFRP) wide-flange-section pultruded profiles, filled in with foam blocks, is presented. The material properties of the GFRP profiles were obtained both theoretically and experimentally. Experimental tests to choose the appropriate resin to bond the concrete to the GFRP profiles and to select the appropriate short fiber and volume fraction to be used in the concrete top have also been conducted. The slab was designed to sustain constructive loads and live pedestrian loads for footbridge deck applications. To investigate the slab flexural behavior up to failure, three specimens were tested under four-point bending, and theoretical and finite element analyses were also performed. Comparisons of theoretical, numerical and experimental results show good agreement. Studies under way to complete the development of the proposed slab are briefly described at the end of the work.

Strength Analysis of Precast Bridge Decks with Full-Depth Precast Overhang Panels

The use of full-depth precast overhang panels provides an alternative to modern bridge deck construction by eliminating the need to form a full-depth cast-in-place (CIP) overhang. Additional benefits from these precast panels include improving worker safety conditions during construction and accelerating construction. To validate the capacity of a full-depth precast bridge deck system compared with a conventionally constructed concrete bridge deck, the Texas Department of Transportation sponsored an experimental investigation. For both, the failure loads exceeded the maximum factored 2007 AASHTO load and resistance factor design for decks and deck overhangs. Observations suggest that there is an interaction between flexure and shear to estimate the capacity of full-depth concrete bridge deck overhangs or slabs constructed with stay-in-place (SIP) panels and a CIP topping. This paper shows how a modified yield line theory, which accounts for the development length of the mild steel reinforcing to reach yield strength, is used to analyze precast bridge decks with full-depth precast overhang panels. For the full-depth overhangs, the internal work equation is further modified to allow for the panel-to-panel seam that exists within the system. At the interior portions of the bridge deck, a compound shear–flexure mechanism is proposed. This is an additive model of a flexural yield line failure in the lower SIP precast panels and punching shear in the upper CIP portion of the deck. Therefore, a strength method of analysis is used to design the exterior portion (overhang) that incorporates the concurrent effects of flexure and shear in panelized precast deck systems.

Rapid Bridge Deck Replacement Construction Techniques

Rapid bridge deck replacement (RBDR) is the method of replacing a bridge deck using innovative, alternative deck systems to perform needed repair under an accelerated construction schedule. Through employing RBDR techniques, state highway agencies (SHAs) can meet current transportation challenges by repairing the nation's bridges while minimizing construction-related impacts. SHAs in the United States were surveyed on their experience with RBDR projects. Survey results are divided into the following categories: decision-making factors, construction schedules, construction techniques, contractual methods, costs, and innovations in safety or technology employed. Of the 52 responding agencies, 24 have experience with RBDR; 54% have less than 5 years of experience, and 63% have completed fewer than five RBDR projects, suggesting that the practice is new and most agencies are inexperienced. The strongest factors influencing decision making are traffic volume, critical bridge, safety, and impact on local business. Most RBDR projects are performed on highways and freeways, in both urban and rural areas. Lane closures are the most common closure scenario, which allows construction to proceed while maintaining partial throughput capacity. Most agencies use nighttime closures, which reduces road user impact and provides a safer environment. Although 86% of the responding agencies experienced an increase in construction costs, 68% agreed that RBDR projects are perceived as a cost-saving mechanism for road users. Information collected from this survey, along with lessons learned and safety and construction technologies employed, allow knowledge to be transferred to practitioners who may have little or no experience with RBDR techniques.

Characterization of High Early-Strength, Self-Consolidating Concrete for Design of Pretensioned Bridge Elements

Self-consolidating concrete (SCC) is an innovative construction material that can be placed into forms without mechanical vibration. Precast, prestressed concrete plants require that the concrete used to fabricate their structural members attain high early strength. High early-strength SCC could provide significant value for precast plants. However, the high early-strength SCC mixture constituents, proportions, and construction may affect the hardened properties, and SCC may not provide the same performance as conventional concrete. SCC and conventional concrete mixture proportions designed for precast, prestressed bridge elements were evaluated to characterize the associated mechanical properties, shear characteristics, bond characteristics, and creep. To assess the applicability of SCC in prestressed girder systems, four full-scale girder–deck systems containing conventional concrete and SCC precast girders were fabricated and tested. Results from this research indicate that the AASHTO Load and Resistance Factor Design Specifications can be used to estimate the mechanical properties of high early-strength SCC. With respect to shear characteristics, a more appropriate expression is proposed to estimate the concrete shear strength for SCC girders with a compressive strength greater than 10 ksi (69 MPa). Bridge girder–deck systems containing relatively small (Texas Type A) girders containing high early-strength SCC exhibited similar flexural performance as bridge girder–deck systems with girders containing conventional concrete. Results indicate that the AASHTO equations for computing the nominal moment capacity, strand transfer length, and strand development length may be used for SCC girder–deck systems similar to those tested in this study.

Ultimate strength of a steel–concrete composite bridge deck slab with profiled sheeting

The ultimate behaviour of a steel–concrete composite deck slab system with profiled steel sheeting and perfobond rib shear connectors was experimentally investigated. The main objectives of this study are to develop a composite deck slab for girder bridges that spans longer but weighs less than the conventional reinforced concrete (RC) deck slab and to experimentally validate the proposed deck slab system. Eight deck specimens were tested with different shear span lengths to evaluate the horizontal shear capacity of the proposed deck system by using the empirical m – k method. To examine the ultimate load-carrying capacity of the proposed deck slab system under sagging and hogging bending actions, two full-scale deck slab specimens supported by a set of steel box blocks were fabricated and tested. The ultimate strength and initial concrete cracking load of the proposed deck system under hogging bending action are approximately 2.5 and 7.1 times greater than those of an RC deck, respectively, while the deck weighs about 25% less than RC deck systems.

Conformable Tire Patch Loading for FRP Composite Bridge Deck

Fiber-reinforced polymer (FRP) composites are increasingly being used in bridge deck applications. However, there are currently only fledgling standards to design and characterize FRP deck systems. One area that should be addressed is the loading method for the FRP deck. It has been observed that the type of loading patch greatly influences the failure mode of a cellular FRP deck. The contact pressure distribution of a real truck loading is nonuniform with more concentration near the center of the contact area as a result of the conformable contact mechanics. Conversely, the conventional rectangular steel patch on a FRP deck act like a rigid flat punch and produces stress concentration near the edges. A proposed simulated tire patch has been examined for loading a cellular FRP deck with the load distribution characterized by a pressure sensitive film sensor and three-dimensional contact analysis using ANSYS. A loading profile is proposed as a design tool for analyzing FRP deck systems for strength and dur...

Fibre-reinforced polymer in railway civil engineering

Network Rail owns and operates Britain's railway infrastructure, and has been a leading client in the adoption of fibre-reinforced polymers (FRP), initially for bridge strengthening and then for other civil engineering related applications. It now owns over 20 FRP-strengthened bridges, three fully FRP bridge, and several fibre-reinforced polymer platform decks, and has recently installed the first known application of an FRP secondary decking system for carrying railway live loading. Other applications of FRP are under development. This paper describes the background to the adoption of FRP for railway civil engineering, and the safeguards put in place to ensure satisfactory performance. A number of completed schemes are used to illustrate typical applications, and those planned in the immediate future are described. The paper also looks briefly at FRP related research supported by Network Rail.

Briefing: FRP railway decking – Calder Viaduct

This paper describes the first known application of fibre-reinforced polymer (FRP) composites for structural re-decking of a railway bridge for full railway and derailment load. Calder Viaduct crosses the River Calder near Sellafield in Cumbria. The original bridge comprised three spans of half-through-type steel girders with timber decking and ballasted rail, constructed in 1922. Due to the coastal location of the viaduct, significant corrosion of the steelwork and deterioration of the timber decking had occurred. This type of timber railway decking on a metallic supporting superstructure is common throughout the UK. The structure was chosen by Network Rail for a pilot project for replacement of the timber decking with FRP composite materials. The chosen FRP decking solution comprised a standard pultruded glass-fibre-reinforced polymer (GFRP) deck with bonded and bolted GFRP top plate for ballast retention and wear resistance. Other types of FRP deck, such as bonded FRP pultruded sections and bespoke vacuum-cured FRP decks, were also considered. The choice of an FRP decking system was driven by a number of factors; ease of installation, adaptability, minimum depth/weight, compliance testing, durability/design life and cost. The installation method, design challenges such as achieving compliance for derailment loading, and procurement issues such as developing a generic specification to enable competition, are discussed. Conclusions are given on the factors that require consideration by the designer to deliver a competitive FRP solution in accordance with best practice, and a brief comparison with equivalent performance steel decking is included.

Concurrent multi-scale modeling of civil infrastructures for analyses on structural deterioration—Part I: Modeling methodology and strategy

This paper aims to develop the methodology and strategy for concurrent finite element modeling of civil infrastructures at the different scale levels for the purposes of analyses of structural deteriorating. The modeling strategy and method were investigated to develop the concurrent multi-scale model of structural behavior (CMSM-of-SB) in which the global structural behavior and nonlinear damage features of local details in a large complicated structure could be concurrently analyzed in order to meet the needs of structural-state evaluation as well as structural deteriorating. In the proposed method, the “large-scale” modeling is adopted for the global structure with linear responses between stress and strain and the “small-scale” modeling is available for nonlinear damage analyses of the local welded details. A longitudinal truss in steel bridge decks was selected as a case to study how a CMSM-of-SB was developed. The reduced-scale specimen of the longitudinal truss was studied in the laboratory to measure its dynamic and static behavior in global truss and local welded details, while the multi-scale models using constraint equations and substructuring were developed for numerical simulation. The comparison of dynamic and static response between the calculated results by different models indicated that the proposed multi-scale model was found to be the most efficient and accurate. The verification of the model with results from the tested truss under the specific loading showed that, responses at the material scale in the vicinity of local details as well as structural global behaviors could be obtained and fit well with the measured results. The proposed concurrent multi-scale modeling strategy and implementation procedures were applied to Runyang cable-stayed bridge (RYCB) and the CMSM-of-SB of the bridge deck system was accordingly constructed as a practical application.

Performance Evaluation of FRP Composite Deck Considering for Local Deformation Effects

We examine here the replacement of a deteriorated concrete deck in the historic Hawthorne Street Bridge in Covington, Va. with a lightweight fiber-reinforced polymer (FRP) deck system (adhesively bonded pultruded tube and plate assembly) to increase the load rating of the bridge. To explore construction feasibility, serviceability, and durability of the proposed deck system, a two-bay section (9.45 by 6.7 m ) of the bridge has been constructed and tested under different probable loading scenarios. Experimental results show that the response of the deck is linear elastic with no evidence of deterioration at service load level (HS-20). From global behavior of the bridge superstructure (experimental data and finite- element analysis), degree of composite action, and load distribution factors are determined. The lowest failure load ( 93.6 kips or 418.1 kN ) is about 4.5 times the design load ( 21.3 kips or 94 kN ), including dynamic allowance at HS-20. The failure mode is consistent in all loading conditions ...