Deck Replacement Research Articles

Splice Length of Large Diameter Reinforcing Bars in Ultra-High-Performance Concrete

Potential exists for construction time savings through replacement of cast-in-place substructure columns, piers, or both, with prefabricated bridge elements and systems. Cast-in-place substructure construction requires forming, placing steel, and pouring concrete at the construction site. Using prefabricated elements would decrease the extent of work required at the site and potentially reduce concrete curing time. This research furthers the effort to use ultra-high-performance concrete (UHPC) as a joining material for prefabricated bridge substructure elements. UHPC has a high early strength, requires less development or splice length than conventional concrete, and has been used previously for accelerated construction projects, such as bridge deck replacement with precast units. UHPC also has a discontinuous pore structure that reduces liquid ingress, significantly enhancing durability compared to conventional concrete. Although UHPC has been researched extensively, previous research for reinforcing bar splice and development lengths has focused on #9 and smaller diameter bars. Typically, larger diameter bars are used for substructures. This research determined the required splice lengths for large diameter steel deformed reinforcing bars embedded in UHPC based on 127 individual tests. Three primary variables were included in the testing matrix: bar size, bar spacing, and concrete cover. To achieve at least 75 kips per square inch (ksi) (517 MPa) reinforcing bar stress in UHPC with an early age strength of 14 ksi (97 MPa), the required embedment length ranges from 8 to 13 times the bar diameter and the corresponding splice length varies from 6 to 11 times the bar diameter, depending on the bar size and concrete cover.

Evaluation of Infrared Thermography Dataset for Delamination Detection in Reinforced Concrete Bridge Decks

Structural health monitoring and condition assessment of existing bridge decks is a growing challenge. Conventional manned inspections are costly, labor-intensive, and often risky to execute. Sub-surface delamination, a leading cause of deck replacement, can be autonomously and objectively detected using infrared thermography (IRT) data with developed deep learning AI models to address some of the limitations associated with manned inspection. As one of the most promising classifiers, deep convolutional neural networks (DCNNs) have not been utilized to their fullest potential for delamination detection, arguably due to the scarcity of realistic ground truth datasets. In this study, a common encoder–decoder semantic segmentation-based DCNN is adapted through domain adaptation. The model was tuned and trained on a publicly available dataset to detect subsurface delamination in IRT data collected from in-service bridge decks. The authors investigated the effect of dataset augmentation, class imbalance, the number of classes, and the effect of background removal in the training dataset, resulting in an overall number of seventy-five UNET models. Four out of five bridges were adopted for training and validation, and the fifth bridge was for testing. Most models averaged 80 iterations, and the training progress finally reached a training accuracy of 75% with a loss of about 0.6 without any overfitting. The result showed a substantial difference in the minimum and maximum values for the evaluated performance metrics (0.447 and 0.773 for global accuracy, 0.494 and 0.657 for mean accuracy, 0.239 and 0.716 for precision, 0.243 and 0.558 for true positive rate (TPR), 0.529 and 0.899 for true negative rate (TNR), 0.282 and 0.550 for F1-score. The results also indicated that the models trained on the raw annotated balanced dataset performed best for half of the metrics. In contrast, the models trained on raw data (with no dataset enhancement) performed better when only global accuracy was considered.

An overview of integral abutments: Current practices, field monitoring and deck replacement measures

The use of integral abutments in bridges goes back many years to the late 1930’s in the United States. Over the years, integral bridges became more popular as more and more states built those bridges and more engineers became familiar with their design and construction. These bridges are being built in Europe since the 1980’s. An integral abutment bridge acts as a frame structure with a continuity connection between the superstructure and the substructure. The substructure is typically an integral cap supported on single row of piles that provides flexibility to accommodate thermal loads and displacements. The main advantage of integral abutment bridges is that they are built without expansion joints which eliminates maintenance costs and reduces construction costs. Because of the interaction between the soil and the integral abutment under the applied loads and the cyclic nature of thermal loads, the analysis and design of integral abutment bridges can be, in some cases, challenging especially when the designs falls outside the geometrical limits set by existing standards. This overview focus on field performance data reported in the literature and interpretation of this data. IT also highlights the needs for more test data during construction and for long term performance under cyclic thermal movements. Deck replacement requirements in integral abutments were investigated using analytical models and recommendations for deck replacement preparations are provided.

Stress change calculations in accidentally damaged prestressed bridge girders

Accidental damage to prestressed concrete bridge girders may occur due to impact by over-height vehicles on the bottom of the girder, or the top flange of the girder may be damaged during deck removal and replacement operations. Since stress checks at service loads are an important component of design for prestressed concrete beams, serviceability-based stress checks should be considered when assessing the structural condition of damaged girders. In this paper, step-by-step theoretical calculations are used to develop equations for estimating service load stress changes due to physical damage (partial loss of concrete section and strands) based on a differential approach. The effects of lack of symmetry in the damaged cross section is considered in the calculations. A spreadsheet-based program is developed to calculate complex section property values for the damaged sections. The accuracy of the developed equations was verified using a finite element model of a prestressed beam under undamaged and damaged conditions. Reasonably good agreement was noted between the predicted stress changes and the finite element results.

Development of High Early-Strength Concrete for Accelerated Bridge Construction Closure Pour Connections

Abstract: Accelerated bridge construction (ABC) has become a popular alternative to using traditional construction techniques in new bridge construction and existing bridge deck replacement because of the reduction of time spent in field activities. A key feature of bridges built using ABC techniques is the extensive use of prefabricated components. Prefabricated components are joined in the field using small volume closure pours involving high performance materials (steel and concrete) to ensure adequate transfer of forces between components. To date, the materials developed for closure pours have been based on proprietary components, so a need has arisen for development of mixes that use generic components. The goal of this research was to create a method to develop concrete mixtures that are designed using generic constituents and that satisfy performance requirements of accelerated bridge construction closure pours in New England, primarily high early strength and long-term durability. Two concrete mixtures were developed with a primary goal of reaching high-early strength while maintaining constructability. The secondary goal of the concrete mixtures was to be durable; therefore, measures were taken during the development of the concrete mixture to generate a mixture that also had durable properties.

Increasing Inventory Rating Factor of Steel Truss Bridge Through Orthotropic Steel Deck Panel Application

Currently, 18,648 bridges with a total length of 510,366 km have been constructed in Indonesia, but only 86% are in good condition, while the rest are damaged. Steel truss bridge damage generally occurs on the RC decks, and its repair is often implemented through deck replacement or redecking using Orthotropic Steel Deck (OSD) panel. In Indonesia, this method has only been applied limitedly at the Citarum I Bridge in 2009 and the Cisadane Bridge in 2013, while the effect on the existing steel truss bridge is unknown. Therefore, this study aims to evaluate the steel truss bridge performance after OSD panel redecking through numerical modeling. The design process of the OSD panel was carried out by micro-modeling on ABAQUS CAE using shell elements with a mesh size of 50x50 mm and pinned boundary conditions. In this stage, the materials were assumed to be elastic with small deformations. The evaluation of steel truss bridge performance was performed on the A-class steel truss bridge Bina Marga design standard with a 60 m span by comparing the existing bridge inventory rating factor (using RC decks) to OSD panel redecking, which is an indicator of bridge self-weight reduction. Based on the structural macro-model developed using SAP2000, the bridge self-weight reduced the axial tension and compression forces on the steel truss bridge mainframe by 20.6%-24.6% and 20.5%-24.5%, respectively. Consequently, this increased the inventory rating factor by 9.3%-9.5%. In other words, using the OSD panels lighter than the existing RC decks increases the steel truss bridge capacity to resist the live load or vehicle rating throughout its service life.

Integrative Evolutionary-Based Method for Modeling and Optimizing Budget Assignment of Bridge Maintenance Priorities

Recently, the number of deteriorating bridges has drastically increased. As such, enormous amounts of resources are invested yearly to maintain the performance of bridges within acceptable levels. This entails the development of bridge management systems to manage the imbalance between the extensive needs for maintenance, repair and rehabilitation actions, and the limited available funds. In this regard, the present study introduces a three-tier platform to model and allocate limited resources in maintenance projects. The first model involves building a discrete event simulation model to mimic the bridge deck replacement process. The second encompasses structuring an efficient and straightforward surrogate machine learning model for mimicking the computationally expensive discrete event simulation model. In the second phase, a novel hybrid Elman neural-network invasive-weed optimization model is developed for predicting the time, cost, greenhouse gases, and utilization rates of resource allocation plans using a database generated from the previous model. The third constitutes the formulation of a multiobjective differential evolution optimization model subject to the utilization rates of the involved resources and their dispersion. Results manifest superiority in cost prediction accuracies, achieving a mean absolute percentage error, mean absolute error, and root-mean-squared error of 4.873%, 78.466%, and 39.515%, respectively. Additionally, the developed multiobjective optimization model significantly outperformed a set of well-performing metaheuristics, yielding a hypervolume indicator, generational distance, spacing, diversity, spread, and coverage of 81.721%, 0.029%, 0.1881%, 0.5229%, 0.9618%, and 0.4087%, respectively. The results also demonstrate the developed multiobjective optimization model accomplished an improvement in the minimization time, cost, and greenhouse gases by 71.01%, 27.87%, and 39.29%, respectively, when compared against a genetic algorithm. The developed models are automated through the hybrid programming of C#.net and MATLAB. It is expected that the developed method can enable the practitioners and transportation agencies to establish timely-efficient, cost-effective, and sustainable resource allocation plans while accommodating the efficacious utilization of resources.

Accelerated testing of super lightweight UHPC waffle deck under heavy vehicle simulator

A super lightweight deck can enhance load rating and functionality of a bridge, especially those identified as structurally deficient. This study was aimed to develop and experimentally validate a novel bridge deck as an ultra-lightweight low-profile waffle slab of ultra-high-performance concrete (UHPC) with either carbon fiber reinforced polymer (CFRP) or high strength steel (HSS) reinforcement. The proposed system lends itself to accelerated bridge construction, rapid deck replacement in bridges with load restrictions, and bridge widening applications without the need to replace girders. Performance and failure modes of the proposed deck were initially assessed through extensive lab experiments and finite element analysis, which together confirmed that the proposed deck panel meets the AASHTO LRFD requirements. The proposed deck system is not susceptible to punching shear of its thin slab and fails in a rather ductile manner. To evaluate its long-term performance, the system was further tested under the dynamic impact of wheel load at the Accelerated Pavement Testing (APT) facility of the Florida Department of Transportation using a Heavy Vehicle Simulator (HVS).

Proposal of longitudinal joint structure during bridge deck replacement and experimental verification of the durability by moving wheel load test

Proposal of longitudinal joint structure during bridge deck replacement and experimental verification of the durability by moving wheel load test

Prediction of Remaining Life for Bridge Decks Considering Deterioration Factors and Propose of Prioritization Process for Bridge Deck Maintenance

Aged highway bridges have become substantially prevalent in recent years. Moreover, combined deterioration, caused by using deicing agents in winter, has led to increased bridge maintenance costs. Accordingly, to extend the service life of bridge decks, this study utilized actual inspection data and major deterioration factors to derive the remaining service life of bridge decks. Based on this study, the following three factors are selected: deicing agent exposure grade, pavement condition state, and surface improvement status. Performance degradation curves were derived for 11 cases that considered the representative three deterioration factors, and the performance degradation of decks was examined for each deterioration factor. Additionally, a process to determine maintenance priorities, using the current condition of highway bridges and the deterioration factors of individual bridges, was proposed. The maintenance demand was predicted based on the end of deck life, which indicated that the demand for deck replacement will sharply increase in 15 years, and that the decks of more than 2000 bridges will reach the end of life in 40 years. Furthermore, this paper proposes a process for prioritizing the maintenance of approximately 9000 highway bridge decks. By applying the prioritization process for bridge deck maintenance to the bridge deck, not only can the life of the bridge deck be extended, but also environmental pollution can be minimized. Additionally, an optimizing design for bridge decks, by considering the remaining life and deterioration factors, can be possible. Therefore, it is expected that the sustainability of the bridge deck can be accomplished.

Finite-Element Fatigue Analysis of a New Rib-to-Floor Beam Connection for Orthotropic Steel Decks

The potential fatigue performance of a new type of rib-to-floor beam (RFB) connection for orthotropic steel decks, the slit connection, was investigated via finite-element analysis. The slit RFB connection combines aspects of the previously used fitted RFB connection and extended cut-out RFB connection. Various slit geometries, floor beam restraint conditions, floor beam geometries, finite-element analysis meshes, and loading conditions were studied. The results show that the slit RFB connection is well suited for orthotropic steel decks in bridge deck replacement applications, where the orthotropic deck is supported by existing, stiff, transverse floor trusses (or floor beams) that are often present in existing long-span cable-supported bridges.

Shear performance of high-strength bolt connector considering different pad and bolt hole

Better than traditional stud connectors, the high-strength bolts enable rapid assembly of steel–concrete composite beams and replacement of decks. However, the researches on the shear performance of high-strength bolt connectors in prefabricated steel–concrete composite beams are relatively limited. Existing studies have not considered the effect of bolt holes in concrete slabs on structural performance. In this paper, the shear performance of high-strength bolt connector of prefabricated steel–concrete composite beams was investigated. The shear bearing capacity, shear stiffness and failure mode were obtained by push-out test. The impact of different bolt hole diameters and pad sizes were considered. Bolt hole diameter of 24 mm, 28 mm and 32 mm, pad size of 50 mm × 50 mm, 80 mm × 80 mm, 200 mm × 100 mm were used in the push-out tests. The results showed that all the specimens were damaged due to crushing of concrete along with shear deformation of bolts. Increasing the pad size can effectively reduce the cracking of concrete slab and improve the slip load and post-slip shear stiffness of specimens. The slip load and peak load of specimens are mainly dependent on the diameter of bolt hole. Specimens with small bolt hole achieve significantly higher pre-slip and post-slip shear stiffness compared to specimens with large bolt hole diameter.

Increase in Coating Thickness of Epoxy-Coated Steel Reinforcing Bars for Concrete Deck Replacement

Increase in Coating Thickness of Epoxy-Coated Steel Reinforcing Bars for Concrete Deck Replacement

Girder–Deck Interface: Partial Debonding, Deck Replacement, and Composite Action

Girder–Deck Interface: Partial Debonding, Deck Replacement, and Composite Action

Feasibility of long-term NDT programme for system-wide monitoring of bridge deck condition in Indiana, USA

Through effective and proactive monitoring, highway agencies can acquire information needed for deck repair or replacement timing decisions. However, system-wide monitoring of infrastructure requires a large expenditure outlay and therefore needs to be justified by comparing its costs to the potential savings if such monitoring leads to timely actions. This paper presents a framework that considers two strategies for managing a bridge deck network: a condition-based strategy that involves monitoring and repair and a time-based strategy that involves repairs at specific time intervals without condition monitoring. Using a case study, the paper calculates the life-cycle cost of each strategy as the sum of the monitoring and repair costs. The paper estimates that if a non-destructive test (NDT) is used as the monitoring platform system-wide, the unit monitoring cost will be $0·04–0·35/ft2 ($0·43–3·77/m2) of deck (average $0·22/ft2 ($2·37/m2)). This cost is expected to be different for other inventories due to differences in age, inventory size and bridge proximities. The paper determines that the NDT monitoring programme benefits outweigh its costs ($3·68–10·42 rate of return in repair savings for every dollar of investment in that programme). The paper also analyses the sensitivity of the outcome to key evaluation factors.

A design approach of integral-abutment steel girder bridges for maintenance

Integral abutment bridges (IABs) have no joint across the length of bridge and are therefore also known as jointless bridges. IABs have many advantages, such as structural integrity, efficiency, and stability. More importantly, IABs have proven to be have both low maintenance and construction costs. However, due to the restraints at both ends of the girder due to the absence of a gap (joint), special design considerations are required. For example, while replacing the deck slabs to extend the service life of the IAB, the buckling strength of the steel girder without a deck slab could be much smaller than the case with deck slab in place. With no deck slab, the addition of thermal expansion in the steel girders generates passive earth pressure from the abutment and if the applied axial force is greater than the buckling strength of the steel girders, buckling failure can occur. In this study, numerical simulations were performed to estimate the buckling strength of typical steel girders in IABs. The effects of girder length, the width of flange and thickness of flange, imperfection due to fabrication and construction errors on the buckling strengths of multiple and single girders in IABs are studied. The effect of girder spacing, span length ratio (for a three span girder) and self-weight effects on the buckling strength are also studied. For estimation of the reaction force of the abutment generated by the passive earth pressure of the soil, BA 42/96 (2003), PennDOT DM4 (2015) and the LTI proposed equations (2009) were used and the results obtained are compared with the buckling strength of the steel girders. Using the selected design equations and the results obtained from the numerical analysis, equations for preventing the buckling failure of steel girders during deck replacement for maintenance are presented.

Lightweight UHPC-FRP Composite Deck System

A new lightweight, low-profile composite deck system is presented that was fabricated using vacuum-assisted resin transfer molding. The deck in this system is composed of ultrahigh-performance concrete (UHPC) for high compressive strength and durability, carbon-fiber-reinforced polymer (CFRP) for high tensile strength, and glass-fiber-reinforced polymer (GFRP) for shear resistance. The high-performance modular deck panels are beneficial for applications such as movable bridges, where spans may be mechanically lifted, and deck repair or replacement, where transportation and installation assist in accelerated bridge construction. Seven single-unit deck specimens were fabricated with two different spans (1,220 and 864 mm) and tested under two different flexural load configurations (wheel-tire load and four-point load). The experimental results demonstrated that the target recommended strength demand for this deck was satisfied prior to failure as a result of delamination of the top UHPC plate from the core. Analysis of the results and corresponding finite-element models (FEMs) showed that the load-transfer mechanism was limited by the crushing of the UHPC plate and interfacial bond with the core.

Effect of Modification of Deck Properties on Suspension Bridges

Different type of deck configuration has been used for suspension bridge depending upon different design requirements. Changes in deck properties lead to changes in behavior of a suspension bridge. In this study, effect of deck modification of a existing bridge from timber to steel deck is considered. Three dimensional finite element models is developed and analyzed changing the deck material from timber to steel which causes reduction in weight and changes in design parameters. This changes the dynamic behavior of the bridge and affects the performance of bearings. The study has been carried out in real world problem encountered in Mugling Suspension Bridge over Trishuli River in Nepal. The study has come up with conclusions and recommendations to increase mass of deck material and replacement of bearings for better performance.Journal of the Institute of Engineering, 2016, 12(1): 39-50

Comparison between major repair and replacement options for a bridge deck life cycle assessment: A case study

Material production, manufacturing, transportation, usage, and end of lifeprocessing are usually the main contributors defining the life cycle assessment (LCA). Bridge infrastructure is important to the economy and the society. Over their life cycle, highway bridges experience several stressors that can significantly affect their structural performance and therefore require rehabilitation. This paper discusses the life cycle analysis of bridge rehabilitation decisions and demonstrates the analysis with a case study of a bridge located in Ontario, Canada. The LCA of the bridge deck is analyzed for two rehabilitation strategies: major repair and replacement. The study focuses on evaluating the different life cycle phases of the bridge deck by assessing their carbon dioxide emission, energy consumption and cost. Also, the paper presents the impact of the different elements within each phase to identify the most contributing elements. The LCA of the bridge deck is analyzed and estimated with the aid of CES EduPack 2016 software that includes a database of more than 4000 different materials and more than 200 manufacturing processes. Analysis of the case study shows that material phase causes significant life cycle impact. The study concluded that the deck replacement yields higher environmental impact and life cycle cost compared to repairing and strengthening the deck.

A proposal of quick deck replacement by support beams for composite bridges

A proposal of quick deck replacement by support beams for composite bridges