Throughout the United States accelerated bridge construction is becoming increasingly popular to meet growing transportation demands while keeping construction time and costs to a minimum. This research focuses on eliminating the need to form full-depth concrete bridge deck overhangs, accelerating the construction of concrete bridge decks, by using full-depth precast prestressed concrete deck panels. Full-depth precast overhang panels in combination with cast-in-place (CIP) reinforced concrete are experimentally and analytically investigated to assess the structural performance. Experimental loaddeformation behavior for factored AASHTO LRFD design load limits is examined followed by the collapse capacity of the panel-to-panel seam that exists in the system. Adequate strength and stiffness of the proposed full-depth panels deem the design safe for implementation for the Rock Creek Bridge in Fort Worth, Texas. New failure theories are derived for interior and exterior bridge deck spans as present code-based predictions provide poor estimates of the ultimate capacity. A compound shear-flexure failure occurs at interior bays between the CIP topping and stay-in-place (SIP) panel. Overhang failure loads are characterized as a mixed failure of flexure on the loaded panel and shear at the panel-to-panel seam. Based on these results design recommendations are presented to optimize the reinforcing steel layout used in concrete bridge decks.

Due to their structural efficiency and architectural elegance, concrete arches have long been used in bridge applications. However, the construction of concrete arches requires significant temporary supporting structures, which prevent their widespread use in modern bridges. A relatively new form of arch bridges is the network arch, in which a dense arrangement of inclined hangers is used. Network arches are subjected to considerably smaller bending moments and deflections than traditional arches and are therefore suitable for modern, accelerated construction methods in which the arches are fabricated off-site and then transported to the bridge location. However, service-level stresses, which play a critical role in the performance of the structure, are relatively unknown for concrete network arches and have not been sufficiently investigated in the previous research on concrete arches. The primary objective of this dissertation is to improve the understanding of short-term and time-dependent stresses in concrete arches, and more specifically, concrete network arches. The research presented herein includes extensive field monitoring of the West 7th Street Bridge in Fort Worth, Texas, which is the first precast network arch bridge and probably the first concrete network arch bridge in the world. The bridge consists of twelve identically designed concrete network arches that were precast and post-tensioned before they were transported to the bridge site and erected. A series of vibrating wire gages were embedded in the arches and were monitored throughout the construction and for a few months after the bridge was opened to traffic. The obtained data were processed, and structural response parameters were evaluated to support the safe construction of the innovative arches, identify their short-term and time-dependent structural behavior, and verify the modeling assumptions. The variability of stresses among the arches was also used to assess the reliability of stress calculations. The results of this study provide valuable insight into the elastic, thermal, and time-dependent behavior of concrete arches in general and concrete network arches in particular. The knowledge gained in this investigation also has broader applications towards understanding the behavior of indeterminate prestressed concrete structures that are subjected to variable boundary conditions and thermal and time-dependent effects.

This thesis investigates the behaviour of UHPC as a fill material for precast deck panels subjected to negative bending. Two full-scale test specimens were constructed. The transverse joints between the panels, the shear pockets, and the deck haunches were all filled with UHPC. A total of four tests were performed including two static tests to failure and two fatigue tests, one of which was performed to failure. Testing consisted of a loading apparatus acting upwards on the deck soffit in an attempt to impose tensile stresses across the transverse joints, representing the conditions that a transverse joint in the negative moment region of a continuous bridge deck would experience. It was concluded that the transverse UHPC joint performed satisfactorily by transferring bending stresses and shear stresses across the joint from one panel to the adjacent panel. Overall, the test specimens displayed performance levels expected from conventional cast-in-place concrete deck alternatives. / February 2016

The effectiveness of Building Information Modelling, or BIM, in the construction industry has become a hot topic of debate. Used in the AEC (Architecture, Engineering and Construction) industry for over a decade now, its effectiveness to certain aspects and sectors of the industry is under constant review. Its implementation into the Swedish bridge construction sector is relatively new, especially when used during the production phase of a projects delivery. This paper aims to investigate how using a 3D BIM during the production phase can improve the performance of production, whilst exploring ways in which to improve the handling of 3D BIM for future projects. This is achieved by following the production phase of the Roforsbron project in Arboga, Sweden. The first of its kind to utilise 3D BIM tools throughout its entire production phase. The theoretical framework focuses on the concepts of constructability, lean construction and productivity as well as reviewing a variety of literature on the benefits and drawbacks of BIM. The empirical data has been gathered through personal involvement of the Röforsbron project, where structured and semi-structured interviews with the workforce make up the bulk of the findings. Empirical observation and practical participation of activities on-site complement the opinions of the personnel. The interviews focus on individuals’ experiences using 3D BIM and their opinions on its effect of the production of the Röforsbron. The problems affecting current production performance often stem from a lack of detailed design and planning that affect constructability. Designing with a larger consideration on how to build and addressing constructability issues early is the means in which production can improve. The Röforsbron project was successful where no rework was performed and attributed many of its savings to the use of 3D BIM. Extra resources and experienced personnel were also a factor in the success of the project. 3D BIM is shown to have the most beneficial effect on the reinforcement works, but also offers a broad range of tangible and intangible benefits to widespread aspects of a bridge project. It is concluded that 3D BIM provides an effective tool in which to improve constructability through facilitating a more detailed design and effective means of understanding through visualisation and communication.

The Accelerated bridge construction (ABC) techniques are gaining popularity among the departments of transportation (DOTs) due to their reductions of on-site construction time and traffic delays. One ABC technique that utilizes precast deck panels has demonstrated some advantages over normal cast-in-place construction, but has also demonstrated some serviceability issues such as cracks and water leakage to the transverse joints. Some of these problems are addressed by applying longitudinal prestressing. This thesis evaluates the service and ultimate capacities in both flexure and shear, of the finite element models of the post-tensioned system currently used by Utah Department of Transportation (UDOT) and a proposed curved-bolt system to confirm the experimental results. The panels were built and tested under negative moment in order to investigate a known problem, namely, tension in the deck concrete. Shear tests were performed on specimens with geometry designed to investigate the effects of high shear across the joint. The curved-bolt connection not only provides the necessary compressive stress across the transverse joint but also makes future replacement of a single deck panel possible without replacing the entire deck. Load-deflection, shear-deflection curves were obtained using the experimental tests and were used to compare with the values obtained from finite element analysis. In flexure, the ultimate load predicted by the finite element model was lower than the experimental ultimate load by 1% for the post-tensioned connection and 3% for the curved-bolt connection. The shear models predicted the ultimate shear reached, within 5% of the experimental values. The cracking pattern also matched closely. The yield and cracking moment of the curved-bolt connection predicted by the finite element model were lower by 13% and 2%, respectively, compared to the post-tensioned connection in flexure.

En la presente tesis se realizó un análisis de vigas híbridas en puentes vehiculares con luces de 50m de Ayacucho, considerando el diseño alternativo en la superestructura de sección compuesta con vigas homogéneas de aceros convencionales que es el proyecto existente versus las vigas híbridas con aceros A709 Grado 50 y de Grado HPS-70W, la misma que determinará cual es la alternativa de diseño que brinda mejores resultados desde el punto de vista como propuesta técnica y económica. Para este análisis se desarrollan seis capítulos. El capítulo número uno, se describe el plan de trabajo a seguir para alcanzar los objetivos planteados. El segundo capítulo, comprende el marco teórico en el cual se definen los conceptos, clasificación de puentes, tipos de aceros estructurales, propiedades, normativas y filosofía de diseño. En el tercer capítulo, se realiza el estudio de caso aplicado a un proyecto existente, donde utilizamos los antecedentes e información del proyecto. En el cuarto capítulo, se realiza el modelamiento y resultados de análisis estructural; en este capítulo se emplea el software SCibridges para el cálculo de las demandas en la estructura. En el quinto capítulo, se realiza el diseño de las vigas en el cual se presenta ensayos de material de una muestra de acero de grado HPS 70W, así mismo, se realiza el diseño de viga I según AASHTO LRFD donde se obtiene resultados considerables para reducir los aceros convencionales. ​Finalmente, en el capítulo seis se presenta las conclusiones y recomendaciones alineados a los objetivos planteados. / In this thesis, an analysis of hybrid beams in vehicular bridges with spans of 50m in Ayacucho was carried out, considering the alternative design in the superstructure of composite section with homogeneous beams of conventional steels that is the existing project versus the hybrid beams with A709 Grade steels. 50 and Grade HPS-70W, which will determine which is the design alternative that provides the best results from the point of view as a technical and economic proposal. Six chapters are developed for this analysis. Chapter number one describes the work plan to follow to achieve the objectives set. The second chapter includes the theoretical framework in which the concepts, classification of bridges, types of structural steels, properties, regulations and design philosophy are defined. In the third chapter, the case study applied to an existing project is carried out, where we use the background and information of the project. In the fourth chapter, the modeling and results of structural analysis are carried out; In this chapter, the SCibridges software is used to calculate the demands on the structure. In the fifth chapter, the design of the beams is carried out in which material tests of a sample of HPS 70W grade steel are presented, likewise, the I-beam design is carried out according to AASHTO LRFD where considerable results are obtained to reduce conventional steels. Finally, chapter six presents the conclusions and recommendations aligned to the objectives set. / Tesis

Accelerated Bridge Construction, also known as ABC, is a methodology that seeks to improve project development of bridges by reducing the overall project schedule and the impact on the traveling public by implementing innovative technologies and strategies in any phase of project development. However, ABC may incur additional direct costs for the project and some risks are associated because of the accelerated constraints implied in this methodology. On the positive side, the opportunity costs and reductions of traffic disruptions costs may overcome the additional costs associated with ABC. Decision-making methodologies for assessment of ABC as an alternative to traditional construction are of great interest for project developers. The topics of research about ABC are diverse but focus mainly on the means and methods, technical aspects, applications, innovations, and decision-making of ABC. Decision-making is of great concern for project developers, especially government organizations, to sustain project goals of serviceability and to validate the additional expenditures in a project. In addition, project developers improve their decisions and project outcomes by reviewing success and failure cases for completed projects in the past. This study seeks to improve the decision-making processes in ABC by finding a more direct correlation of projects to compare by means of a categorization of these ABC projects. Smaller groups in this categorization will help narrow the scope of the characteristics of the projects to consider and to find more relevant lessons learned from the smaller groups of the categorization. To develop the categorization in this study, the data source used is the completed ABC projects database from the Federal Highway Administration (FHWA). The statistical categorization methodology for this study is the Agglomerate Hierarchy Clustering which developed a determined number of cluster based on the closeness among data parameters with "n" number of dimensions of analysis. The number of dimensions for the analysis in this study was established as 13 parameters collected from the database and these were considered critical decision-making parameters and consequential parameters to reflect project decisions and consequences of those decisions. The results of this study rendered 3 categories, and into these categories, 5 sub-categories were distributed according to the same analysis developed. The sub-categories show similarities between the projects according to the parameters established, so the sub-categories help narrow the scope of projects for project developers. As a complement to the categorization, a project matching tool for external projects was also developed to help decision-makers to test their projects according to the analysis in this study and also help developers narrow their review of cases in search for lessons learned. Uses of this study include the prediction of information of parameters according to the variables and ranges in this categorization, and the narrowing of study cases to review. Stakeholders interested can be government organizations seeking to establish the viability of an ABC project, or to improve their project outcomes at any stage of development. Other stakeholders can be designers and contractors that also need to improve their projects at any stage of development. / Master of Science / Accelerated Bridge Construction (ABC) reduces construction time and diminishes traffic disruption by applying strategies and innovations to the way bridges are designed and constructed. However, it implies additional initial costs that need to be justified. Project developers need to evaluate their projects to make decisions to assure the best execution and outcomes. The review of lessons learned from previous bridge projects has been one of the sources that developers have found to find strategies and tips to implement best practices or to avoid mistakes during planning and construction of new bridge projects. This study relies on the lessons learned compiled on the completed ABC project database from the federal transportation authority, the Federal Highway Administration (FHWA), in order to help developers, narrow the scope of projects to be reviewed and find more relevant cases to compare their projects. This scope includes the development of a categorization or a structured hierarchy of completed ABC projects with the FHWA database by applying a statistical analysis and a validation procedure. The results of this study rendered a categorization with 3 categories and 5 subcategories, each with its definition of parameters, which highlight the similarities among projects in the same groups and the differences among different categories. In addition, a framework was developed to match external projects with the categorization in this study to help project developers narrow the projects to review, or even predict missing information according to the parameters in this study. These results may help decision-makers better inform their decisions and support the research in the field of study.

The inverted T-beam bridge system is a bridge construction technique that follows accelerated bridge construction processes. The system was discovered in France and first adopted in the U.S. by the Minnesota Department of Transportation. In 2012 the system was modified and adopted by Virginia, with research being carried out at Virginia Polytechnic Institute and State University (Virginia Tech). The research focused on multiple items involving the system, but the most relevant one is that regarding the transverse bending behavior of the system for different geometries, and joint types between adjacent precast beam members. The study found that using a joint system without any mechanical connection between adjacent beams was most efficient, and gave adequate performance under monotonic loading. The study recommended cyclic load testing be carried out on this joint type, as well as a welded joint similar to those found in decked bulb-T systems. The research contained herein presents the setup and results of this testing. From the work it was found that the no-connection joint behaves adequately under cyclic loading at service loads, however surface roughening between precast and cast-in-place concrete must be adequate. The welded connection behaves well, granted the surfaces to be welded are properly prepared. From these results it is recommended to evaluate different surface roughening techniques, and repeat the cyclic testing using the best. The surface roughening technique chosen should be used to provide guidance on this aspect of construction with inverted T-beams. / Master of Science / The inverted T-beam bridge system is a new type of bridge system intended for use in short to medium length bridges. The system was discovered in France in 2004, where a similar type was being used. It was first modified slightly, and adopted in the in Minnesota. In 2012, the system was again modified to increase its strength and its construction speed, and was then adopted in Virginia. The modifications to the system in Virginia focused on the connections between the individual units making up the bridge, and the geometry of each of these units. The focus of this research was to quantify the long-term performance of two of the connection types currently used on bridges in Virginia. This was achieved by subjecting a test specimen to repeated loads in the laboratory at Virginia Tech. The loading used in the laboratory represented the conditions that a real bridge of this type would be subjected to. The research showed that the two connection types performed well under the repeated loading conditions. However, it was concluded that the concrete surfaces which are in contact with one another must be properly roughened, so that the system maintains its strength. The importance of this research is due to the fact that the large costs associated with maintaining the nation’s bridge infrastructure can be substantially reduced due to this system’s quick and simple construction. In addition to this, road users experience less disruption because of the shortened construction times.

Lap splices are used in reinforced concrete structures to transfer tension forces across discontinuous reinforcing bars to allow for continuity of load path in structural elements. Lap splices of straight reinforcing bars present a number of disadvantages when used in connections of large precast concrete elements typical of bridge substructure. Most importantly, lap splices of large (e.g., No. 11) straight bars are substantially long. Since the closure joint connecting two precast elements must be at least long enough to fit the lap splice, traditional lap splices result in impractically large closure joints, offsetting the benefits of using precast concrete elements. To address this problem, bridge designers are using hooked bars in noncontact lap splices to connect precast elements, presuming that hooked bars will allow for shorter required splice lengths. However, there exists neither substantial design guidance nor studies of the behavior of hooked bar lap splices in large precast elements justifying this design philosophy. To develop design guidance permitting the use of noncontact hooked bar lap splices and address the knowledge gap regarding the behavior of such splices, an extensive experimental and computational research program was conducted which is described in this dissertation. Fifty-eight large-scale beam-splice specimens containing hooked bar lap splices were tested to physically study the behavior of hooked bar lap splices and develop a dataset to justify design guidance permitting the use of such splices in practice. Bond variables were parametrically varied among the test specimens to produce guidance applicable over the wide range of geometric configurations and material properties expected in bridge design. The specimens were subjected to monotonic, four-point loading and were designed to fail in a mode related to anchorage to study splice behavior. Nonlinear finite element analyses were conducted to examine the mechanism of force transfer in hooked bar lap splices and numerically assess splice configurations not experimentally studied. A simple approach to modelling hooked reinforcing bars in solid concrete elements which accounts for conditions of imperfect bond was developed and validated using the experimental results. Test results from the 58 specimens were used to assess the appropriateness of using existing guidance for hooked bar anchorages to design hooked bar lap splices. Because the existing guidance was found to be deficient for this application, descriptive and design equations characterizing hooked bar lap splices were developed using power regression analyses. The results demonstrated that all else being equal, a bottom-cast hooked bar lap splice can develop approximately 40% greater stress than contact lap splices of straight bars. Accordingly, hooked bars can be used to splice bars over a substantially shorter length than straight bars. Noncontact hooked bar lap splices without secondary reinforcement (e.g., ties) can fail due to a mode termed "hook side bulging", resulting from eccentricity between the lapped bars. Splices with secondary reinforcement typically fail due to more typical modes observed in the literature, such as side-face blowout and concrete crushing. Unlike as suggested by code authorities and some researchers for noncontact lap splices of straight bars, noncontact hooked bar lap splices were found to exhibit weaker splice strengths than contact splices as the splice spacing increased. The use of steel fibers and increases in lap length, concrete compressive strength, cover depth, amount of secondary reinforcement, or the number of lap splices allowed for greater stress on average to be developed in spliced bars. All else being equal, an increase in either bar size or the number of spliced reinforcement layers decreased the stress that could be developed in the spliced bars. A descriptive equation characterizing splice strength with an average test-to-calculation ratio and coefficient of variation of 6% was developed. The descriptive equation was adapted to develop a design equation for the minimum required lap length of hooked bars which uniformly characterizes the influence of the bond variables over the ranges explored in this study. Design examples and code language facilitating technology transfer of the design equation into immediate practice were developed. / Doctor of Philosophy / Precast concrete is widely used in highway bridges to enable more rapid and economical construction than could be achieved using cast-in-place concrete. However, the connection of two or more precast, prefabricated bridge elements introduces several difficulties which may inhibit construction, thereby reducing overall economy. One of the most significant difficulties is that connections of substructure elements supporting the superstructures are impractically long using a common, code-approved detail―lap splices of straight reinforcing bars. Such splices are quite long (e.g., 5 ft in length) since large bars are typically used in substructure elements, requiring long splice lengths to transfer the large forces in each bar across the connection. Details which would shorten the required splice length would consequently reduce the required connection length, thereby reducing the amount of cast-in-place concrete construction required in the field. Consequently, the speed of construction, economy, and worker safety would increase. This dissertation thus summarizes an extensive experimental and numerical study aimed at validating the use of noncontact hooked bar lap splices to shorten the required splice length of large precast elements. In support of this objective, the anchorage behavior of noncontact hooked bar lap splices was studied through static load testing of 58 large-scale beam-splice specimens and nonlinear finite element models accounting for bond-slip behavior. These efforts revealed that hooked bar lap splices can develop on average approximately 40% more stress over the same lap length than contact splices of straight bars. Existing design provisions which might presently be used to design hooked bar lap splices were evaluated against the experimental results and were found to be deficient in characterizing splice strength. Thus, a design equation was developed for the splice length of hooked bars which accurately characterizes anchorage behavior and allows for significantly shorter splices lengths than what could be achieved with straight bars.

This thesis investigates the impact of interface surface treatment methods for use in the Virginia Inverted T-Beam bridge system. The specific system consists of precast beams with thin bottom flanges placed next to one another, with a cast-in-place slab on top. Previous research has shown that the strength of this system after cyclic loading is highly dependent upon the shear strength of the interface between the precast and cast-in-place sections, especially for the adhesion-based connection configuration. The approval of this bridge system for use in bridges with high daily traffic volumes hinges on the verification of its strength and durability for a 50-year lifespan. The shear strength of ten different surface textures was tested using push-off tests to determine which interface roughening methods would prove adequate for use in the bridge system. The strength was found to depend on both the amplitude and the geometry of the undulations on the beam-to-slab interface. Using this information, a texture was selected for a new trial of the adhesion-based connection configuration, and a test specimen was constructed. After completing cyclic loading to simulate the design life of the bridge, it was found that the system achieved a strength similar to previous monotonically loaded specimens. It was concluded that the bridge is safe for use in high daily traffic areas provided that a surface roughening with adequate shear strength is used. / Master of Science / The Virginia Inverted T-Beam bridge system was initially designed to be more durable and economical than other types of bridges. The bridge is constructed by arranging prefabricated beams side-by-side across the span before placing fresh concrete overtop. In the most economical version of the system, the only connection between the beams is the newly placed concrete. For the beams and topping to act together, the bond between them must be strong. Roughening the surface of the prefabricated beams increases the strength of the bond, although different roughening patterns achieve different levels of strength. Past tests of the bridge system have utilized inadequate roughing patterns which lead to low bridge failure loads after many loading cycles. This low-cost configuration is currently only approved for use in low daily traffic areas. The goal of this research was to determine a roughening pattern that would result in a high bridge failure load which would allow the low-cost configuration to be approved for high daily traffic areas. Several roughening patterns were investigated and the patterns producing the highest shear strengths were determined. The best pattern was chosen to be used for the bridge configuration and a sub-section of the bridge was constructed. This specimen was subjected to a loading protocol that simulated the traffic that an actual bridge would be subjected to over its life span. The failure load was then measured and found to be high enough to warrant the use of the specific system in high daily traffic areas.