Deck System Research Articles

Material and Structure Performance of RPC Pavements for Steel Bridge Decks

To solve the fatigue cracking problem in orthotropic steel decks (OSD) and to prevent the early damage of bridge pavements resulting from the low stiffness of the bridge deck system, epoxy-resin-perfused concrete (RPC) pavements were developed for improving the modulus and road performance of paving materials. The mechanical and road performance of RPC and the bonding performance of the waterproofing adhesive layer were studied via laboratory experiments. The mechanical property of RPC pavements and their protective function on OSD were analyzed by using a finite element model. Composite beam fatigue life and acceleration loading tests were performed on a scaled model to verify the performance of these pavements. Results show that RPC has excellent high-and low-temperature stability and water stability that can meet the requirements and has a relatively long fatigue life. The bonding strength of RPC pavements and steel plate is better than that of epoxy asphalt concrete and Gussasphalt concrete pavements. RPC pavements have a relatively low tensile stress on the surface and a relatively high shear stress below the surface, but these stresses are far lower than the material strength. When paved with RPC, the stress in the fatigue details of OSD is reduced by more than 20%. The maximum relative deflection between ribs, the minimum curvature radius, and the relative deflection to span ratio of RPC are also favorable, thereby providing additional protection for the bridge deck system. The fatigue life tested with a five-point bending composite beam is more than 1 million times, which meets the requirements. In the acceleration loading test, RPC pavements do not show any rut, whereas the OSD shows no cracking when loaded for 12 thousands times. The engineering application results demonstrate the feasibility of using RPC pavements and show that these pavements and OSD endure no damage.

Shear behaviour of steel-UHPC composite beams in waffle bridge deck

This paper firstly proposed the steel-UHPC composite beam in waffle bridge deck system. Then, the shear behaviour of steel-UHPC composite beams in waffle bridge deck system was studied through two-point loading tests on six large scale specimens. The influences of shear span, depth of the rib, and width of the UHPC waffle slab were studied in this testing program. The experimental results reported the typical flexure and shear mode of the composite beam, and their respective ultimate strength behaviours in terms of load versus deflection (or strain) curves and load-transferring mechanism. The test results also showed that shear spans changed the failure mode of steel-UHPC composite beams. The height of the rib in the waffle slab acted less importantly than the thickness of slab on improving the shear resistance of composite beam. Theoretical models were also developed to predict the ultimate bending and shear resistances of steel-UHPC composite beams. The validations of the predictions against reported six test results showed that the developed theoretical models offered conservative estimations on shear resistance, but more accurate estimations on flexural bending resistance.

Influence of profile deck sheet in composite slab system

Composite structures play a vital role in construction sector due to rapid completion of the projects. In composite structures, Plates are mostly used as a structural element for effective replacement of steel reinforcement. Normally the composite floor deck system involves a profile deck sheet as a bottom layer of slab system to take care of the tensile strength of the element. Concrete is poured over a deck sheet and with minimum reinforcement to take care of shrinkage stresses. Profile deck sheet plays a dual role as tensile reinforcement when concrete hardens and act as a temporary shuttering during fresh concreting. The main objective of this paper is to determine the vibration characteristics of profile deck sheet for various shapes of profile as composite slab system. Modal analysis is a technique in which vibration studies can be determined for various profile shapes by involving parameters such as mode shape, natural frequency, plate stresses and deformation by using finite element analysis.

Experimental feasibility study of a new attached hydronic loop design for geothermal heating of bridge decks

Geothermally heating of bridges is a green and sustainable alternative to deicing chemicals, which are energy-intensive, corrosive to the bridges, and dangerous to the environment. Geothermal bridges harness shallow earth geothermal energy, a readily available all-year-round renewable energy source. However, the existing geothermal heated bridge technology was developed based on embedded hydronic loops, which can be only deployed during the construction of new bridges. As there are more existing bridges in the critical need of deicing, a new attached hydronic loop design was developed in this study for geothermal heating of existing bridges. The hydronic loops are attached to the bottom of a bridge deck and are encapsulated inside an insulation material geofoam. The developed hydronic loop was tested on a lab-scale concrete deck with supplied warm water to evaluate its feasibility for field application. This heated deck system was fabricated and instrumented for the heating performance tests in an environmental chamber. It was first tested under various room temperatures higher than 4.4 °C, the lowest temperature permitted by the environmental chamber. Based on the test results, an empirical prediction equation is presented to estimate deck temperature at given ambient and supplied heating fluid temperatures. The applicability of this equation to freezing temperature was validated in localized freezing tests by placing a cooling box on the test deck. All test results show that this heated bridge deck allows efficient heat transfer, approximately 60% of the supplied heat, to the bridge deck surface. The supplied heat flux to the deck surface ranges from 120 to 270 W/m2 depending on the ambient and heating fluid temperature, which is comparable to the embedded hydronic system. The new hydronic loop design is feasible to be implemented on the existing bridges for deicing and snow removal.

Developing A Semi-Markov Process Model for Bridge Deterioration Prediction in Shanghai

The performance of urban bridges will deteriorate gradually throughout service life. Bridge deterioration prediction is essential for bridge management, especially for maintenance planning and decision-making. By considering the time-dependent reliability in the bridge deterioration process, a Weibull distribution based semi-Markov process model for urban bridge deterioration prediction was proposed in this paper. Historical inspection records stored in the Bridge Manage System (BMS) database in Shanghai since 2004 were investigated. The Weibull distribution was used to characterize the bridge deterioration behavior within each condition rating (CR), and the semi-Markov process was used to calculate the bridge transition probabilities between adjacent CRs. After that, the service life expectancy of urban bridges, the transition probabilities of the deck system and the substructure, and the future CR proportion change caused by deterioration was predicted. The prediction results indicate that the life expectancy of concrete beam bridges is about 77 years. The decay rate of the deck system is the fastest among three major parts, and the substructure has a much longer life expectancy. It suggests that the overall prediction accuracy of the semi-Markov model in network-level is better than the regression analysis method. Furthermore, the proportion of bridges in intact condition will gradually decrease in the next few decades, while the percentage of bridges in the qualified and bad state will increase rapidly. The prediction results show a good agreement with the actual deterioration trend of the urban bridges in Shanghai. In order to alleviate the pressure of bridge maintenance in the future, it is necessary to adopt a more targeted preventive maintenance strategy.

FLEXURAL BEHAVIOR OF HYBRID FRP-CONCRETE BRIDGE DECKS

The main aim of this study is to investigate the behaviour of hybrid FRP-concrete decks. The hybrid FRP-concrete bridge systems consisting of different FRP cell units available on the market such as trapezoidal, triangular, honeycomb, rectangular with alternating diagonal, half-depth trapezoidal, hexagonal and arch cell units were computationally compared and examined using the finite element (FE) analysis to decide the most appropriate FRP composite deck for bridge systems. Design criteria such as the deflections were considered in selecting the most effective unit system. Different FRP bridge deck panels were analysed under static loading representing the standard European truck wheel. The finite element analysis of bridge deck systems was performed using a general purpose finite element analysis package ABAQUS, and the behaviour of these systems was then be compared in terms of stiffness and strength criteria.The results showed that Delta, Super and ASSET hybrid decks are stiffer than other deck systems. The results from FEA approach also indicated that the layer of concrete on the top surface of bridge deck reduces the vertical displacement of FRP bridge systems approximately 60%.

Colocación endoscópica por vía occipital de catéteres ventriculares permanentes. Nota técnica

El siguiente trabajo constituye una nota técnica sobre un nuevo proceder endoscópico de colocación de catéteres ventriculares permanente a través del cuerno occipital. Se colocaron 20 catéteres permanentes utilizando el sistema DECK con un endoscopio Hopkins II de 30°, diámetro 2,7 mm y longitud 30 cm, con vainas y canales de trabajos. La posición del catéter fue evaluada por tomografía de cráneo realizada a las 24 horas de la cirugía, obteniéndose una posición a (óptima) en el 95% de los casos, con una distancia promedio de 10,5 cm desde la tabla externa del hueso occipital al cuerno frontal. En ninguno de los casos disfuncionó el sistema derivativo y un solo paciente presentó como complicación un hematoma del lecho quirúrgico.

Preparation and properties of flame‐retardant damping polyurethane and its application in floating deck

Flame‐retardant modified polyurethane (PU) damping layers were prepared using the combination of expandable graphite (EG), aluminum hydroxide, and phosphorus‐nitrogen flame‐retardant HF600B. The mechanical, thermal, damping, and flame retardancy properties of PU damping layer and the sound insulation, vibration damping, and fire resistance of the deck components were studied systematically. The results revealed that the incorporation of flame retardant depressed the mechanical performance in general, and there was no significant change in damping property. At the same time, the residual char ratio of damping layer increased obviously with the addition of HF600B, the vertical burning rating was upgraded from V‐2 to V‐0 and passed the low flame test of marine materials. The A60 fire test showed that the floating deck system with damping layer had a maximum temperature rise of 75°C on the backfire surface during the test, which is much lower than 180°C required in the A60 grade fire resistance and has good fire resistance. Sound insulation test of the deck components showed that only a 2 mm damping layer increased the average sound insulation by 3 dB, especially in the low‐frequency range by about 8 dB. The vibration test showed that the damping effect of the floating damping deck system on the steel plate surface and the dressing surface is increased by 1.1 and 4.0 dB in the range of 10–200 Hz, 9.2, and 4.7 dB in the range of 200–1,500 Hz, respectively. POLYM. ENG. SCI., 59:2136–2147, 2019. © 2019 Society of Plastics Engineers

Considerations concerning the calculation of the reliability of deck systems

As is well known, the calculation of the reliability of series and parallel systems is solved in the literature. To calculate the reliability of deck systems, methods based on the formula of Bayes are currently being used. In this paper we present a method of calculating the reliability of triangle-star systems and of transforming a triangle system into a star-type system that then leads to the calculation of the reliability of the deck systems.

Structural investigation of the snow-melting heated bridge deck based on the thermal field distribution

This paper aims to improve the energy utilization of the snow-melting heated bridge deck system with a thermally conductive layer (SHBD-TCL) and reduce its deformation caused by the non-uniform thermal field distribution. Therefore, three structures of the SHBD-TCL were proposed, and there are thermally conductive layers and heating cables embedded in different layers. Then, the finite element models corresponding to the above structures were developed. The energy utilization and the deformation caused by the thermal gradient were analyzed, and the embedded spacing and embedded depth were set as input factors. Also, the effective energy ratio and the maximal deformation were set as the optimization targets, and their prediction models were established based on the above input factors. Finally, to obtain greater effective energy ratio and less deformation, the multi-objective optimization was applied to achieve the optimum structure and rational parameters. The optimum structure was selected to conduct the laboratory experiments, which verified the reasonability of the finite element model of SHBD-TCL. The research enriches the thermodynamic structure design theory of the snow-melting bridge system.

Dynamic Bayesian network-based system-level evaluation on fatigue reliability of orthotropic steel decks

Fatigue fractures can be frequently observed in welded joints in orthotropic steel decks (OSDs) after just a few decades of operation, which become the major deterioration mechanism deterring the serviceability of OSDs. In this paper, a novel dynamic Bayesian network (DBN) model has been established for the fatigue reliability analysis of OSDs at system-level. The exact inference algorithm is applied in the DBN model with discrete variables. Special modifications have been made on the existing algorithm to improve the computational efficiency in dealing with the deck system consisting of a considerable number of joints. Using the DBN model, the fatigue reliability of welded joints can be predicted and updated with the inspection and monitoring results at system-level. At the same time, a framework is established for the system-level reliability considering the fatigue fracture of rib-to-deck (RD) joints, the dominant cracking pattern affecting the serviceability of OSDs. For illustration, a typical OSD bridge in China has been selected to carry out a case study. To derive the stress spectrum required by the DBN model, the stochastic traffic model is employed, and the influence-based Monte Carlo simulations have been carried out. As a result, the fatigue reliability can be predicted at both component- and system-levels. Meanwhile, the observation of the traffic and the inspection result has been fused into the DBN model to update the deteriorating state of the deck system. Besides, the effect of enhancement and maintenance has been highlighted, including the enhancement in fatigue strength at the construction stage, and the repair and traffic control during the operation stage.

Stochastic Multi-Objective Optimization-Based Life Cycle Cost Analysis for New Construction Materials and Technologies

The sustainability of transportation infrastructure depends on the adoption of new construction materials and technologies that can potentially improve performance and productivity. However, most agencies would like to evaluate these new materials and technologies at both the project and network levels before replacing the traditional ones. It also remains a challenge to reliably estimate the costs and lifetime performance of new construction materials and technologies because of limited implementation data. To address these issues, this paper presents a comprehensive bottom-up methodology based on Life Cycle Cost Analysis (LCCA) to integrate project- and network-level analysis that can fast-track the acceptance of new materials or technologies. Hypothesized improvement rates are applied to the deterioration functions of existing materials to represent the expected improved performance of a new material compared with a conventional material with relatively similar characteristics. This new approach with stochastic treatment allows us to probabilistically evaluate new materials with limited data for their future performance. Feasible maintenance and rehabilitation schedules are found for each facility at the project level and near-optimal investment strategies are identified at the network level by using a metaheuristic evolutionary algorithm while satisfying network-wide constraints. This provides an effective solution to many issues that have not been fully addressed in the past, including the trade-off between multiple objectives, effects of time, uncertainty, and outcome interpretation. A hypothetical bridge deck system from New Jersey’s bridge inventory database is used to demonstrate the applicability of the proposed methodology in constructing a planning and management decision-support procedure.

Flexural cracking behavior and crack width predictions of composite (steel + UHPC) lightweight deck system

This paper aims to clarify flexural cracking behaviors (e.g., crack width and crack spacing) of a lightweight deck system composed of steel orthotropic deck and thin ultra-high performance concrete (UHPC) layer. Forty steel-UHPC composite plates and eight steel-UHPC composite beams were tested to explore their cracking characteristics in transverse and longitudinal directions, respectively. The influences of reinforcement ratios, the thickness of the UHPC cover, the spacing of stud shear connectors, and the depth of the UHPC layers on cracking behaviors were examined. According to the bridges with composite deck systems recently constructed in China, the same spacing of reinforcing bars were employed in longitudinal and transverse directions, which ranged from 30 and 75 mm. The test results show that the occurrence and growth of cracks in UHPC layers could be effectively restricted by increasing reinforcement ratios, reducing the thickness of UHPC cover and the spacing of stud shear connectors, as well as thickening the UHPC layer. For the average crack spacing, the most significant factor was the reinforcement ratio. For the longitudinal behavior of the lightweight deck system, the steel-UHPC composite beams would fail due to the yield of steel U-ribs and the crack width in the UHPC layer would be small (e.g., 0.09–0.14 mm) when the reinforcement ratio and the thickness of UHPC cover are design appropriately. Based on the experimental observations, the formulas were developed to estimate the stress in reinforcements for the composite (steel + UHPC) lightweight deck system. The reinforcement stresses predicted by these formulas were in agreement with the experimental data. A new formulation for predicting the maximum crack width in composite (steel + UHPC) lightweight deck system was also proposed. Good agreements were achieved between the test results and the predicted values of the flexural crack width.

Reinforcement Analysis of Rigid Hangers for Existing Old Arch Bridges: A Case Study of Ling Bridge

Ling Bridge, built in 1936, is an old half-through riveted steel arch bridge with rigid hangers and a floating deck system. The effects of various factors, such as temperature, vehicle load, and crowd load, have caused large additional stresses on the rigid hangers. According to the inspection in 2011, the bridge was in a dangerous state. Therefore, improving the structural strength of the bridge and prolonging the service life for another 40 years while protecting the cultural relic were major problems. This study analyzes rigid hangers on the premise that the reinforcement schemes of other bridge components have been determined. First, the damage situation, material properties and mechanical behaviors of old hangers are evaluated. Second, an appropriate reinforcement method is proposed. Third, mechanical and fatigue analyses are conducted on the new structures to prove the rationality of the reinforcement method. For the undemolished old structures, a fracture assessment of existing damage is performed to obtain the evolution laws and ensure safety. Finite element calculations and fatigue fracture analyses show that the proposed reinforcement method for the hanger system can reduce all hangers’ stresses effectively to prolong service life and protect the cultural relic.

Experimental study on fatigue performance of UHPC-orthotropic steel composite deck

UHPC-orthotropic steel composite deck is an innovative and efficient bridge deck system, however the failure mode of this composite bridge deck under fatigue load is still not well understood, particularly when the deck is in hogging bending. To investigate the fatigue behavior of the UHPC-orthotropic steel composite deck, two multi-span full scale composite bridge decks in hogging bending were experimentally studied. To simulate the bridge deck under negative bending, the specimens were designed with the mid-span deck simply supported and two overhanging decks each side. Each specimen was tested twice. In the first test phase, the specimen was loaded with a vertical force acting on one side span, while in the second test phase, the specimen was vertically loaded on another side span. Tests revealed that among the all fatigue-prone details of an orthotropic steel deck, only the longitudinal cracks were observed occurring in the low portion of rib web which was near the weld toe of the rib to the transverse diaphragm. The fatigue strength of these specific cracks longitudinally orientated can be evaluated in a term of the vertical stress range of the rib below the weld toe under the fatigue details category C of AASHTO or category 71 MPa of Eurocode3. Shear connection failure of the composite deck was also found featuring with delamination between UHPC and steel bridge deck. Fatigue damage of the short headed studs was further inspected and evaluated by means of drilling test. It is found that the fatigue life of the shear connection is governed by the fatigue shear strength of the short headed studs, which is much longer than the fatigue life codified in the specifications for studs of conventional composite beams. The fatigue shear connection strength of the composite bridge deck can be assessed conservatively in a term of the fatigue shear strength of the headed studs.

Development of Fully Prefabricated Steel-UHPC Composite Deck System

AbstractThis paper proposes a novel fully prefabricated composite deck system to achieve green and accelerated construction in bridge engineering. Ultra-high-performance concrete (UHPC), which has ...

Performance Evaluation of a New Precast Concrete Bridge Deck System

Performance Evaluation of a New Precast Concrete Bridge Deck System

Kinematics and Structural Analysis for 5ton cargo-truck Elecrto-Hydraulic Sliding Deck Systems Manufacturing and Design of winch system for safety

Kinematics and Structural Analysis for 5ton cargo-truck Elecrto-Hydraulic Sliding Deck Systems Manufacturing and Design of winch system for safety

Remaining Strength Estimation Methods of Plate Girders with Corrosion and the Practical Evaluations

In steel plate girder railway bridges with open deck system, damage caused by local corrosion of the upper flanges under sleepers is well-known. This damage reduces ultimate strength of the main girders significantly (e.g., in the case of 50%-corroded upper flanges, approximately 30 percent reduction in bending strength). This paper presented a simple evaluation method for estimating the remaining strength of the plate girders that have local corrosion damage under sleepers. Remaining strength of the damaged plate girders can be calculated by taking into account both the remaining strength for local load (hereinafter referred to as “patch load”) that acts directly on the upper flanges under the sleepers, and the remaining strength for bending load that acts on the main beam itself. This new evaluation method using the equations proposed in this paper, is based on the idea that the remaining strength under pure bending load can be obtained as the minimum value of strengths calculated in light of the various buckling modes of the compression flange, while taking the thickness reduction due to corrosion into account. Thereafter, the remaining strength under patch load only can be calculated by using an equation which is further simplified based on Takimoto’s original equation. Finally, the remaining strength of the plate girder as a whole is obtained from the strength interaction curve between patch and bending loads. In addition, by comparing the estimated remaining strengths obtained through this method with those obtained from nonlinear Finite Element Method (FEM) analyses using full-scale beam models, it could be concluded that the simple evaluation method by using both new and original equations can estimate the remaining strength of plate girders with corroded flanges under sleepers with around 95 percent accuracy.

Transverse fatigue behaviour of steel-UHPC composite deck with large-size U-ribs

With increasing traffic volumes, fatigue of orthotropic steel decks (OSDs) has become a critical issue in recent years. In this study, an innovative composite deck composed of large-size U-ribs, a thin ultra-high-performance concrete (UHPC) layer and headed studs is proposed to enhance the fatigue properties of OSDs. Experimental and numerical approaches were combined to investigate the transverse fatigue behaviour of the proposed composite deck. A large-scale composite deck specimen was fabricated and tested under cyclic loading. The experimental results revealed the progressive failure process of the composite deck. The effects of damage accumulation in UHPC layer and headed studs on the mechanical behaviour of steel-UHPC composite deck were evaluated. The results indicated that the mechanical degradation in the composite deck system accelerated the damage accumulation in the fatigue-prone details of OSDs. It is necessary to consider the effects of mechanical degradation in fatigue resistance evaluation.