Dissertations / Theses on the topic 'Concrete arch bridge'

Masonry arch bridge building declined considerably in· the twentieth century due to the development of faster methods of construction, such as reinforced concrete. However, in recent years, the repair and maintenance of bridge structures has become a major concern. The lower maintenance costs and longer 'design life of arch bridges over alternative bridge designs were key reasons in the selection of several arch bridges built towards the end of the twentieth century and the beginning of the twenty first century. The FlexiArch design allows a masonry arch system to be cost competitive with other forms of bridge systems while offering superior durability and lower long term maintenance. The aim of this research was to extend the knowledge of the FlexiArch bridge system into the behaviour of FlexiArch bridge systems with skew and to address the shortfalls found in the literature review. The literature review demonstrated that skew arches are complex 3D structures, and that the assumptions used in current 2D analysis methods to define the effects in the transverse direction often incorrectly predict the behaviour of the skew arch. This research investigated the behaviour of the skew FlexiArch bridge system through a detailed experimental test programme. The experimental test programme involved the design, construction and testing of five third scale skew FlexiArch bridge systems with varying angles of skew. As the skew angle was increased, and the square span and square width were kept constant, the peak load decreased. The skew arch systems transferred the load along the shortest load path; namely the square span direction where possible, or the shortest distance in the highly skewed arch systems. The experimental test data was compared against an analytical model and a 3D NLFEA model, which were found to accurately predict the behaviour of the skew arch.

The new Ashton Bridge is a concrete tied-arch structure with a cable-supported deck, which spans 110 metres below the arching ribs. The tie-beam members, connecting the arch ribs, each have six longitudinal tendons that have primarily straight profiles. The author set out to validate the structural behaviour of the tie-beams, after the post-tensioning construction stage. This objective was achieved by validating selected finite element model parameters with field conducted tests. The input parameter, which is the prestress loading onto the structure, was validated with tendon elongation measurements and tendon lift-off tests. The output parameter, which is the strain and displacement response of the structure, was verified by measuring the elastic deck shortening and the strain gauge readings. Lower tendon extensions were encountered during tensioning. This required calibration of the friction coefficients and model updating. Lift-off tests and deck shortening measurements provided and order size estimation of the structural behaviour, but was not adequate for model validation. The strain gauge readings showed a close correlation with the expected strain state of the structure and offered insight into the behaviour of the structure during post-tensioning. The methods described in this dissertation may be used for validating the structural behaviour of concrete bridges subject to post-tensioning. Suggestions for improving tendon lift-off tests and deck shortening measurements are also presented.

The work presented in this thesis comprises the assessment of existing arch bridges with overlying backfill. The main objective is to estimate the load carrying capacity in ultimate limit state analysis. A case study of the old Årsta railway bridge is presented, serving as both the initiation and a direct application of the present research. The demand from the bridge owner is to extend the service life of the bridge by 50 years and increase the allowable axle load from 22.5 to 25 metric tonnes. The performed analyses show a great scatter in estimated load carrying capacity, depending on a large number of parameters. One of the factors of main impact is the backfill material, which may result a significant increase in load carrying capacity due to the interaction with the arch barrel. Based on theoretical analyses, extensive conditional assessments and the demand from the bridge owner, it was decided that the bridge needed to be strengthened. The author, in close collaboration with both the bridge owner and the persons performing the conditional assessment, performed the development of a suitable strengthening. The analyses showed a pronounced three-dimensional behaviour, calling for a design using non-linear finite element methods. Due to demands on full operability during strengthening, a scheme was developed to attenuate any decrease in load carrying capacity. The strengthening was accepted by the bridge owner and is currently under construction. It is planned to be finalised in 2012. The application of field measurements to determine the structural manner of action under serviceability loads are presented and have shown to be successful. Measured strain of the arch barrel due to passing train has been performed, both before, during and after strengthening. The results serve as input for model calibration and verification of the developed strengthening methods. The interaction of the backfill was not readily verified on the studied bridge and the strengthening was based on the assumption that both the backfill and the spandrel walls contributed as dead weight only. The finite element models are benchmarked using available experimental results in the literature, comprising masonry arch bridges with backfill loaded until failure. Good agreement is generally found if accounting for full interaction with the backfill. Similarly, accounting for the backfill as dead weight only, often results in a decrease in load carrying capacity by a factor 2 to 3. Still, several factors show a high impact on the estimated load carrying capacity, of which many are difficult to accurately assess. This suggests a conservative approach, although partial interaction of the backfill may still increase the load carrying capacity significantly.
Arbetet i föreliggande avhandling omfattar analyser av befintliga bågbroar med ovanliggande fyllning. Huvudsyftet är att uppskatta bärförmågan i brottgränstillstånd. En fallstudie av gamla Årstabron redovisas, vilken utgör både initieringen och en direkt tillämpning av föreliggande forskning. Kravet från broförvaltaren är att öka brons livslängd med 50 år, samtidigt som axellasten ska ökas från nuvarande 22.5 ton till 25 ton. Utförda analyser visar på stor spridning i uppskattad bärförmåga, beroende på ett stort antal parametrar. En av de främsta faktorerna är fyllningens egenskaper, vilken kan resultera i en markant ökning av bärförmågan p.g.a. samverkan med bågen. Baserat på teoretiska analyser, tillståndsbedömningar och krav från broförvaltaren beslutades att bron skulle förstärkas. En förstärkningsmetod har utvecklats i nära samarbete med broförvaltaren och personer som tidigare utfört tillståndsbedömningarna. Analyserna visar ett utpräglat tredimensionellt beteende, vilket har föranlett användandet av icke-linjära finita elementmetoder. Krav på full trafik under samtliga förstärkningsarbeten har resulterat i att dessa utförs enligt en föreskriven ordning, som ska reducera minskning i bär­förmåga under samtliga etapper. Förstärkningsförslaget godkändes av Banverket och är för närvarande under byggnation. Enligt plan ska dessa slutföras under 2012. Fältmätningar har använts för att bestämma det statiska verkningssättet under brukslaster, vilket visas ge goda resultat. Resulterande töjningar från passerande tåg har uppmäts i bågen, både före, under och efter förstärkning. Resultaten har använts både för att kalibrera beräkningsmodeller och att verifiera utförda förstärkningar. Samverkan mellan båge och fyllning har inte kunnat verifierats för den aktuella bron och de utvecklade förstärkningarna baseras på en modell där både fyllning och sidomurar endast utgör yttre verkande last. De framtagna finita element modellerna har jämförts med experimentella resultat från litteraturen, omfattande tegelvalvsbroar med ovan­liggande fyllning belastade till brott. Generellt erhålls god överensstämmelse om full samverkan mellan båge och fyllning antas. Om fyllningen istället endast betraktas som yttre last, minskar lastkapaciteten ofta med en faktor 2 till 3. Fortfarande uppvisar ett antal faktorer stor inverkan på bärförmågan, vilka ofta är svåra att med säkerhet bestämma. Ett konservativt betraktningssätt rekommenderas, även om delvis sam­verkan med fyllningen fortfarande kan öka bärförmågan avsevärt.
QC 20110426

As Americaâ s infrastructure ages, many of the nationâ s bridges approach the end of their service life. In order to develop a method for handling the rising number of deficient and functionally obsolete bridges, nondestructive tests and evaluations must be undertaken. Valuable information from these tests regarding the strength and condition of bridges will help in making decisions about their rehabilitation and replacement.

Two adjoining open spandrel reinforced concrete arch bridges in downtown Appalachia, Virginia were selected for live load testing by Virginia Department of Transportation (VDOT). Both bridges have supported an increasing amount of extreme coal truck traffic throughout their service life and are essential to the efficient transport of coal in the region. Because of their age, having been built in 1929, and the amount of visible damage and repairs, VDOT was concerned about their remaining capacity and safe operation.

The live load tests focused on global behavior characteristics such as service strain and deflection as well as local behavior of the arches surrounding significant repairs. It was found that the strain and deflection data collected during load testing displayed linear elastic behavior, indicating excess capacity beyond the test loads. Also, given the loading applied, the measured strains and deflections were small in magnitude, showing that the bridges are still acting as stiff structures and are in good condition. Data collected during these tests was compared to results from a finite element model of the bridges to determine the coal truck size which is represented by the live load test loading configurations. The model comparisons determined the test loads produced comparable deflections to those produced by the target coal truck load. Through this approach, a recommendation was given to VDOT regarding the satisfactory condition of the aging bridges to aid in the process of load rating and maintenance scheduling for the two bridges.
Master of Science

The subject of this master's thesis is design of road bridge over highway D1 by the city Přerov. From the three proposed solutions has been chosen bridge with self-anchored arched structure which is good for deep notch. The concrete bridge was designed and assessed according to current Eurocodes. The thesis includes detailed structural analysis, drawings and visualization of the bridge. The analysis was performed using software Scia Engineer including time dependent analysis (TDA). Assessment of structure was made in Excel or by hand.

The subject of this master’s thesis is the design of footbridge across the river. The main objective is to analyse the superstructure which is formed by a stress ribbon and arch. The arch consists of two separate plan curved concrete arches and is associated with stress ribbon in the top. The analysis of the structure has been performed using MIDAS CIVIL 2011 software. Simplified calculations by hand or by EXCEL have been also carried out. Design of the superstructure's elements, pre-stressed tendons and reinforcement has been done according to EUROCODE. In the analysis, time dependent effects have been also taken into account.

The subject of this diploma thesis is design of arch bridge across the highway. Has been elected self-anchored structure with span of arch 60 m and trapezoid bridge deck from prestressed concrete. The load effects is calculated by software Scia Engineer including time dependent analysis. The supporting structure is assessed for the ultimate limit state and serviceability limit state. Static assessment is done by hand calculation according to CSN EN 1992-2. Part of the thesis is drawing and visualization of the bridge.

Diploma thesis deals with a design of concrete arch structure. There was made a preliminary design of concrete structure of a buried arch bridge. Subsequently was the shape of arch structure optimized to oblige the requirements of real buried arch bridge structure. There is included static calculation of the ecoduct construction. It is developed detailed drawings

The aim of this thesis is the design of curved footbridge across the river Bečva. Curved footbridge consists of a supporting steel arch, which brings the steel struts to the steel arch under the concrete deck. The steel arch with crosspieces is coupled with concrete deck using the coupling pins. The deck is formed from reinforced concrete. Structural model is carried out in a computer program ANSYS. The structural design is handled in accordance with applicable European standards. The design considers pedestrians load and temperature effects.

Subject of the work is design of pedestrian bridge across the river Morava. There are compared 3 variants of structures. Thesis is focused on stress ribbon supported by arch. The geometry of initial stage has been searched to form self-anchored structural system. The structure is verified in according to the European Standards.

The aim of this thesis is the design and analysis of pedestrian bridge across the deep valley. There were designed three variants. The variant of structure, which combines stress ribbon with concrete arch, was chosen for the analysis. The optimal geometry was found using iteration methods with VBA Excel. The calculation model was made in software Ansys 19.0, considering phases of construction. The Ultimate limit state and the service limit state were evaluated as well as dynamic behavior of construction – modal analysis (eigenfrequencies and eigenshapes) and response to harmonic excitation. The design and assessment are according to the European standards.

The objective of this theses is arch bridge design over the expressway. Bridge is consist of bridge deck, which has three pillars and composite arc. The Bridge deck is on the edges fixed into the foundations and in the middle adherent on overhead cables. The bridge is carried by combination of strands and aerial cables mounted on reinforced concrete arch. Overhead cables are slant due to the transverse direction of the bridge in the longitudinal direction is in the direction of the arc. Model of the construction was made in a calculated program SCIA ENGINEER 2011. The designe is in accordance with applicable standards.

The diploma thesis deals with design and assessment of steel arched bridge with the semi through bridge deck placed on the third-class road. This steel structure is drawn up to bridge water barrier – the river Olše in Návsí. The distance between axes lay on abutments is 48,5 meters. The bridge´s supporting structure consists of two steel arches angled towards each other and fastened to the foundation blocks. The supporting beam of the bridge deck is tied to the arch by tie-rods. The tie-rods are designed to the V-shaped system.

The content of the thesis is a proposal of steel load-bearing structure (carrying structure of a steel) bridge of the span of 31+74+31m with the bottom bridge deck taking over the second-class road in the territory of Olomouc city. The bridge deck is created by composite steel-concrete slab with crossbars. The solution was focused on using arched construction in the middle of the bridge with different tilt of arches to the horizontal central axis of the bridge. Under the term of the solution four alternatives have been calculated. The most optimal solution was selected and processed in detail. The calculations were made in compliance with the Czech technical norms ČSN EN.

The scope of thesis is to design a curved arch footbridge. The main structure consists of composite deck supported by steel arch. The focus is on finding optimal shape of arch and proper cross-sections of elements. Bridge is analysed according to limit states.

Diploma thesis deals with constructive technological preparation of bridge structure SO-201. This 86m long bridge is located in a non-built-up area of the city of Nitra in Slovakia. Bridge structure is part of project Highway R1 Nitra, západ - Selenec. Bridge is formed by a self-anchored arch structure with intervening bridge deck.The bridge superstructure is formed by steel arches filled with concrete ,steel girders and beams locked with a reinforced concrete slab.

The thesis is devoted to analysing of flexible buried arch structures. Modelling of the flexible concrete arch is carried out via a nonlinear finite element model that accounts for soil constitutive relations, soil-structure interactions, sequential construction stages and soil compaction. Advanced FE-model was verified by measurement obtained by full-scale field testing of two buried arches. Mathematical optimization methods of genetic algorithms and Levenberg-Marquardt method are applied to already calibrated complex computational models in order to reduce bending and associated flexural stresses in the concrete section of buried arch. Centre line of the arch is parameterized by cubic Bezier curve to reach interpolation of thrust line. Optimization technique is applied with extensive parametrical study which shows the optimal shapes for buried arches of various span/rise ratios, backfill depths and foundation soil types. For practical application are given coordinates of Bézier curve control polygons of particular resulting shape. Subsequently is applied optimization method for a theoretical reduction of tensile stresses obtained by shape optimization of previously verified numerical model of buried arch. Comparisons of earth pressure, bending moment axial force and deflection of flexible structure during sequential construction of different span/raise ratios of buried arches are presented. The behaviour of flexible buried arch with effect of local traffic load model LM1 has been analysed via 3D finite elements model with respect to different depth of backfill above crown.

In this thesis, new design concepts for arch bridges using ultra high-performance fibre-reinforced concrete are developed for spans of 50 to 400 m. These concepts are light-weight and efficient, and thus have the potential to significantly reduce the cost of construction. Lightness is achieved by the thinning of structural components and the efficient use of precompression in the arch, rather than by the decrease of bending stiffness. Using the advanced properties of the material, the design concepts were shown to reduce the consumption of concrete in arch bridges by more than 50% relative to arches built using conventional concrete technology. In addition to span length, other design parameters including span-to-rise ratio and deck-stiffening were considered, resulting in a total of seventy-two design concepts. Other important contributions made in this thesis include: (1) the development of a simple analytical model that describes the transition of shallow arches between pure arch behaviour and pure beam behaviour, (2) a comprehensive comparative study of 58 existing concrete arch bridges that characterizes the current state-of-the-art and serves as a valuable reference design tool, and (3) the development and experimental validation of general and simplified methods for calculating the capacity of slender ultra high-performance fibre-reinforced concrete members under compression and bending. The research presented in this thesis provides a means for designers to take full advantage of the high compressive and tensile strengths of the concrete and hence to exploit the economic potential offered by the material.

The present study examined the application of modern, computer-based analysis methods to two existing historic bridges in Massachusetts. The first bridge featured in this study is the Woronoco Bridge, a reinforced concrete open spandrel arch bridge that was constructed in 1923. It was hoped that a computer-based, parametric study of this bridge would prove it to be deck-stiffened, similar to select bridges of Swiss engineer Robert Maillart. However, the results do not support that there was any intent to reduce bending in the arch as a result of increasing the stiffness of the bridge deck. Instead, the Woronoco Bridge appears to optimize column stiffness in order to reduce bending stresses in the arch. The second bridge featured in this study is the Bardwell’s Ferry Bridge, a wrought iron lenticular truss that was constructed in 1882. A finite element model was created to identify the magnitude and location of maximum stresses within a critical lower truss chord (eye bar) connection in order to aid future rehabilitation and monitoring efforts. In addition, this model was used in combination with currently available material data in order to evaluate the fatigue life expectancy of the structure given the current 10 ton posted capacity. It was determined to be below the endurance limit and therefore is safe indefinitely, however, more specific material data is required.

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.

Rubble Masonry Concrete (RMC), a particulate composite o f large uncut boulders, manually embedded into a mortar matrix, was used in Roman times for constructing robust physical infrastructure, some of which survives. A renaissance of RMC usage has resulted in recognition of its potential to provide competent infrastructure and create employment for the unskilled without costing a premium. Despite numerous successes, the potential of RMC may be threatened by an absence of knowledge of its mechanical properties and a lack of appreciation of the requirements for humans to labour effectively. This thesis explores the mechanical properties and behaviour of RMC as well as physiological factors which govern the physical work capacity of the targeted labour-force before proposing guidelines towards the rational design and manual assembly of RMC structures. In addition to factors known to govern the properties of conventional concrete, potential anisotropy (a consequence of an inherently predominant orientation of elongated inclusions),relative inclusion size and inclusion contiguity appear to characterise RMC. It is hypothesized that as a result of this contiguity, RMC may exhibit a reduced thermal contraction coefficient below its placement temperature; a contributing factor to its resistance to post-hydration cracking. Ultimate failure and deformation of RMC under uniaxial compressive load appear to be governed by mechanisms which evolve between boulder inclusions, often accompanied by rock fracturing as a result o f high inter-particle bearing stresses. Fostering of interfacial bond appears to delay the onset of these mechanisms. Physiological investigation found the cost of human energy high when quantified in terms of the equivalent energy contained in diesel fuel and bread. However, when human-labour is effectively utilised, its versatility, energy efficiency and freedom from fixed ownership costs,enhance its competitiveness, particularly where rival machinery is sub-optimally utilised.Means to improve human-labour effectiveness are discussed. Based upon these findings and experience elsewhere, RMC material specifications and design and construction guidelines for RMC arch bridges of determinable reliability are proposed.They include a proposal that a high partial material factor be applied to RMC and indicate ways to exploit RMC’s anisotropic properties to advantage in highly stressed apphcations.