This research study is aimed at assisting the Texas Department of Transportation (TxDOT) in making a transition from the use of the AASHTO Standard Specifications for Highway Bridges to the AASHTO LRFD Bridge Design Specifications for the design of prestressed concrete bridges. It was identified that Type C and AASHTO Type IV are among the most common girder types used by TxDOT for prestressed concrete bridges. This study is specific to these two types of bridges. Guidelines are provided to tailor TxDOT's design practices to meet the requirements of the LRFD Specifications. Detailed design examples for an AASHTO Type IV girder using both the AASHTO Standard Specifications and AASHTO LRFD Specifications are developed and compared. These examples will serve as a reference for TxDOT bridge design engineers. A parametric study for AASHTO Type IV and Type C girders is conducted using span length, girder spacing, and strand diameter as the major parameters that are varied. Based on the results obtained from the parametric study, two critical areas are identified where significant changes in design results are observed when comparing Standard and LRFD designs. The critical areas are the transverse shear requirements and interface shear requirements, and these are further investigated. The interface shear reinforcement requirements are observed to increase significantly when the LRFD Specifications are used for design. New provisions for interface shear design that have been proposed to be included in the LRFD Specifications in 2007 were evaluated. It was observed that the proposed interface shear provisions will significantly reduce the difference between the interface shear reinforcement requirements for corresponding Standard and LRFD designs.The transverse shear reinforcement requirements are found to be varying marginally in some cases and significantly in most of the cases when comparing LRFD designs to Standard designs. The variation in the transverse shear reinforcement requirement is attributed to differences in the shear models used in the two specifications. The LRFD Specifications use a variable truss analogy based on the Modified Compression Field Theory (MCFT). The Standard Specifications use a constant 45-degree truss analogy method for its shear design provisions. The two methodologies are compared and major differences are noted.

As part of the ongoing research on shear at the Phil M. Ferguson Structural Engineering Laboratory (FSEL) located at The University of Texas at Austin, the anchorage controlled shear capacity of prestressed concrete bridge girders was in this research studied in two distinct ways, experimentally and analytically. The results of this research are an important step towards improving understanding of strand anchorage related issues. For the experimental program, two full-scale Tx46 prestressed concrete bridge girders were fabricated at FSEL. The Tx46 girders were topped with a concrete, composite deck. Both ends of the two girders were instrumented and tested. For the analytical program, a new Anchorage Evaluation Database (AEDB) was developed, by filtering and expanding the University of Texas Prestressed Concrete Shear Database (UTPCSDB), and then evaluated. The AEDB contained 72 shear tests, of which 25 were anchorage failures and 47 were shear failures. The results and analysis from the experimental and analytical programs generated the following three main conclusions: (1) A reasonable percentage of debonding in Tx Girders does not have a marked impact on girder shear capacity calculated using the 2010 AASHTO LRFD General Procedure. (2) The AASHTO anchorage equation is conservative but not accurate. In other words, this equation cannot be used to accurately differentiate between a shear failure and an anchorage failure. In regards to conservativeness, anchorage failures in AASHTO-type girders may lead to unconservative results with respect to the 2010 AASHTO LRFD General Procedure. (3) The 2010 AASHTO anchorage resistance model and its corresponding equation do not apply to Tx Girders. Because of the Tx Girders' wider bottom flange, cracks do not propagate across the strands as they do in AASHTO-type girders. This fact yields overly conservative results for Tx Girders with respect to AASHTO Equation 5.8.3.5-1. In summary, this research uncovered the short-sided nature of the AASHTO anchorage design method. Given its short-comings, there is an obvious need for a validated, comprehensive, and rational approach to anchorage design that considers strength and serviceability. To appropriately develop this method, additional full-scale experimental testing is needed to expand the AEDB, as currently there are not enough tests to distinguish major, general trends and variables. Any future additional research would be expected to further validate and expand the significant findings that this research has produced and so take the next step toward safer, more-efficient bridge designs. / text

An effective, viable design solution for the elevated viaduct guideway for Universal Freight Shuttle (UFS) system championed by Texas Transportation Institute (TTI) is presented. The proposed precast elevated UFS bridge system is analyzed for the operational vehicular loading as provided by TTI and a number of design alternatives for the various bridge components are provided. This includes: the design of the fully precast deck panels for long continuous spans, design of the shear connectors resisting interface shear at bridge deck-girder interface, design of structurally efficient and cost-effective trough girders and its design alternative with I-girders, and economic and long-term serviceable design of bridge piers. A literature review and study of the existing precast bridges is presented for the state-of-the-art and practice, design specifications and publications by AASHTO, State Department of Transportation and other agencies. These existing systems are refined to determine the most appropriate specification for the proposed bridge components by integrating the planning, design, fabrication and construction techniques to ensure high precision freight shuttle movement, construction feasibility, safety, life-cycle cost, durability and serviceability requirements. The design concept presented is a deviation from the conventional railways and highways design. The best practices and specifications of AASHTO and AREMA are combined suitably in this research to suit the major requirements of the project. A combination of the design philosophy with appropriate construction techniques has been blended to devise a system which is efficient for offsite manufacture of components for construction of the bridge and adaptable to the different bridge configurations. Based on the design results, it is found that precast concrete deck panels in combination with precast, prestressed concrete trough girders provides the most efficient superstructure solution for this project. The Damage Avoidance Design for the precast bridge piers along with the precast superstructure provides a system with comparable structural performance along with other benefits such as long term serviceability, economical sections, practically transportable units, modular simplicity for relocation as desired and ability to offer space for commercial usage. The steps for construction of the bridge is schematically presented and sequentially explained.

In early 2020, cracks were discovered on the bridge crossing the Torne River at Autio. This resulted in an investigation being launched to determine the structural state of the bridge. In conjunction with this investigation, monitoring equipment was installed on the bridge, which enabled the collection of measured strain at four critical points on the bridge.  In this thesis the measured strain was used to approximate stresses in the prestressing cables and thereby calculate the effects of fatigue on the bridge. Two different structural standards were used to calculate the results: Eurocode 2, and fib Model Code 2010. Likewise, two different cycle-counting methods were used to calculate the results: the Rainflow-algorithm, and the largest-magnitude approach.  Regardless of structural standard or cycle-counting method, the results indicate that the effects of fatigue are neither an issue for the bridge, currently, nor will it be in the expected lifetime of the bridge.

Straßenbrücken im Bestand bilden einen beachtlichen Teil des Anlagevermögens der bundesdeutschen Verkehrsinfrastruktur. Diese existierenden Brücken stellen die verantwortlichen Behörden vor erhebliche Herausforderungen. Einen großen Anteil am Bestand nehmen Brücken in Spannbetonbauweise ein. Viele der heute noch existierenden Konstruktionen sind in der Zeit des wirtschaftlichen Aufschwungs nach den 1960er Jahren in der BRD entstanden. Die Spannbetonbauweise wurde parallel zur Anwendung erforscht und weiterentwickelt. Bestimmte Bauweisen und Bauverfahren bildeten sich heraus, die bis in die Gegenwart angewendet werden. Heute sind diese Brücken veränderten Anforderungen ausgesetzt. Ältere Brücken stehen unter immer höheren Belastungen. Die statische Nachrechnung ist ein Hilfsmittel für Ingenieure zur Beurteilung bestehender Brückenbauwerke. Im Jahre 2011 wurde dazu vom Bundesministerium für Verkehr, Bau und Stadtentwicklung eine Richtlinie zur Nachrechnung von Straßenbrücken herausgegeben. Erfahrungen und Ergebnisse in der Anwendung wurden veröffentlicht. Bei vielen Spannbetonbrücken wurden damit rechnerische Defizite ausgewiesen, die zu einer Einschränkung der weiteren Nutzungsdauer führen. Damit können solche Spannbetonbrücken nicht mehr so lange genutzt werden, wie ursprünglich geplant. Verantwortlich dafür kann u. a. der statische Nachweis der Dekompression sein, bei dem im Beton keine bzw. unter Anwendung der gegenwärtigen Fassung dieser Richtlinie nur sehr geringe Zugspannungen auftreten dürfen. Es werden Spannbetonbrücken betrachtet, die im Taktschiebeverfahren hergestellt wurden. Diese weisen bestimmte Konstruktionsmerkmale auf, sodass hauptsächlich allein der Nachweis der Dekompression noch maßgeblich für die Einschränkung der Nutzungsdauer sein kann. Die Grundlagen des Nachweises der Gebrauchstauglichkeit basierend auf dem bewährten Konzept der zulässigen Spannungen in der früheren deutschen Spannbetonnorm werden erläutert. Diese frühere Norm wird dem Konzept der europäischen Mustervorschrift (Model Code) bis zu den heute gültigen Eurocodes gegenübergestellt. Auf der Einwirkungsseite werden die früheren Lastfälle in das heute nach Eurocode gültige Konzept der Einwirkungskombinationen im Grenzzustand der Gebrauchstauglichkeit eingeordnet. Die Hintergründe der früher zulässigen Spannungen im Beton auf Zug auf der Widerstandsseite werden beschrieben. Die früheren Grenzwerte werden kritisch beurteilt. Es wird herausgearbeitet, dass die gegenwärtige Regelung der Richtlinie beim Nachweis der Dekompression zu ungünstig ist. Ein differenzierteres Nachweisverfahren auf Basis des Eurocodes wird vorgeschlagen. Damit soll die Verkürzung der Nutzungsdauer aufgehoben werden. Wenn sonst keine Einschränkungen bestehen, können mit diesem Vorschlag solche Spannbetonbrücken wenigstens solange genutzt werden, wie ursprünglich vorgesehen. Bei der Anwendung sind Einschränkungen zu beachten. Die Übertragung auf andere Bauweisen von Spannbetonbrücken wäre möglich.

The master´s thesis is about detailed design of highway bridge from prestressed concrete between the cities Brno and Ostrava. The construction is continuous and consists from three fields. Internal forces was taken from software SCIA Engineer. The static assessment was realized according to limit states. Counstruction is evaluated according to the current standards.

Europe experienced the destruction of numerous infrastructures during World War II, followed by a reflation and a strong economic growth during the next two decades allowing a more perennial and durable situation. A classical bridge lasting in general around 80 years, one should observe that these constructions built after the war will have to be either replaced either seriously strengthened in a few years. Besides, since the needs also vary over time, transportation infrastructures built during those years might not be adapted to the actual needs anymore – some bridges might thus have to be widened. A case study has been chosen in order to simulate under which conditions the widening of such a bridge can be performed. This road bridge, located in Vierzon in France, is rather simple since it is made of simply supported prestressed concrete beams and of reinforced concrete piers. It has been chosen in particular for its reduced size – three spans of 30 m each and two road lanes – that corresponded well to this project. Based on some data provided when the bridge was initially built and on a visual inspection, this project suggests six technical solutions to double the actual amount of lanes. An evaluation of the performance of the solutions according to three criteria – durations of works, cost of the works, and environmental impact – is made in order to give recommendations regarding the optimal solution. The results show that in spite of being installed quickly, adding steel beams is more expensive and has a greater impact on the environment than adding prestressed concrete beams. Regarding the modification of piers, the solution suggesting widening the existing piers is preferable than adding new extra piers according to all the criteria. Consequently, among all the solutions analysed, the optimal one is also the simplest one. Finally, the limits of the study and some suggestions for improvements are indicated.

The theme of the master’s thesis is detailed design bridge structure. The thesis is devoted to limit states assessment of the structure. The thesis includes a time analysis structure and a detailed solution influence of construction on its proposal.

No description available.

This thesis describes the design of a road bridge in Trutnov through local communication. It is designed prestressed dvoutrámová construction of two fields with twin inclined struts. It developed a detailed static analysis and the bridge is considered to I. and II. limit state according to European standards - Eurocode. It is prepared detailed drawings.