bluuebunny/crossref_metadata_2025 huggingface dataset:
Reinforcement of the beams of Saint-Nazaire – Saint-Brévin Bridge
Authors: Lanquette Francis
Published: May 2013

A number of beams (out of a total of 120) of the access bridges of the Saint-Nazaire – Saint-Brévin Bridge had some defaults affecting the prestress tendons of the precast concrete beams.

Consequently, the owner decided, in addition to a detailed investigation of the beams, to reinforce the South access decks, from the abutment to the main bridge, which is a steel cable stayed-bridge. The aim of the reinforcement was to increase the prestress and to confer more ductility to the beams. The chosen solution consisted in reinforcing the beams with reinforced concrete cast on the lower part of existing beams. A comprehensive study of the influence of prestress tendon failure was made, modeling failures at various positions and taking into account an increasing number of broken tendons.

Moreover, this study showed the underlying lack of resistance of the beams with regards to shear stress, shear stress reinforcement was thus designed using carbon fibers.

The finite-element software Pythagore developed by Setec tpi allowed us to construct an original model composed of beam and slab elements. With this model a non-linear analysis was performed simulating the deterioration of prestress, progressively deactivating parts of the tendons.
The First European Approval for an Expansion Joint Flexible Plug Joint System with New Material
Authors: Gallai Gustav
Published: May 2013

Up to now the common material used for flexible plug joints of bridges is based on bituminous mixtures consisting of aggregates and polymer-modified binders. All existing national regulations and also the upcoming European Guideline for Expansion Joints ETAG 032 are restricting flexible plug joints to these traditional bituminous mixtures.

The new expansion joint system uses a new material based on polyurethane and shows essential improvements in the intersection pavement/joint by mechanical means. It offers a longer working life, larger movements up to 135 mm, allows for installation both in cold and hot climate and enables new applications, e.g. in railway bridges and building construction.

Due to the existing restricting regulations complete new approaches both for a national and the European Approval (on basis of a CUAP) had to be found to demonstrate the fitness for use and to verify the different requirements on expansion joints for the new system. The paper covers reports on material and system tests executed and shows an example of installation.
Structural Verification throughout the Tensioning Process of Cable-Stayed Bridges
Authors: Lozano-Galant Jose A. , Ruiz-Ripoll Lidia , Payá-Zaforteza Ignacio , Xu Dong , Turmo José
Published: May 2013

Throughout the tensioning process of cable-stayed bridges changes in geometry, boundary conditions, applied loads as well as material properties may produce unacceptable stresses and/or deflections in the structure. Therefore, an appropriate simulation and structural verification of this process is especially advisable in this kind of structures. Nevertheless, the predicted tensioning process rarely coincides with that measured on site. Usually, deviations between actual and predicted structural behaviour are found in every construction stage. If these deviations are so large that the achievement of the pursued stress state cannot be assured after completion or exceeds safety thresholds, an additional tensioning stage is added. Then, the following calculated tensioning operations are needed. If throughout these stages new differences are measured, new additional tensioning stages would be added. The addition of these additional stages on site is both time- consuming, as the tensioning process must be interrupted, and expensive, as more tensioning operations than the initially calculated ones are required.

This paper aims to fill this gap by providing a new method that eases the simulation of deviations in the tensioning strategy on site, the Forward Algorithm. This procedure has been applied to the temporary supports erection method as, despite its importance, no specific investigation of this erection technique has been found in the literature. The Forward Algorithm is especially indicated to control the construction process on site, increasing safety and decreasing construction time.
Assessment and Upgrading of Steel Bridges using Finite Element Modelling
Authors: Icke Philip , Rhodes Steve
Published: May 2013

This paper describes how Finite Element (FE) modelling techniques can assist in the assessment (rating) and upgrading of steel bridges of various types. Global and local modelling options are considered with reference to several projects, in particular the West Gate Bridge in Melbourne, Australia. The use of different analysis assumptions, element types, eigenvalue and nonlinear analysis functions to achieve greater load rating capacity is outlined, identifying examples of good practise and drawing on international codes and literature for recommendations.
Identification of Structural Performance of A Steel-Box Girder Bridge Using Machine Learning Technique
Authors: Kim Hyun-Joong , Park Wonsuk , Koh Hyun-Moo , Choo Jinkyo F.
Published: May 2013

A new procedure for multiple model identification and representative model selection is proposed. Multiple models are generated from the weighted aggregation formulation for multi-objective optimization problem which deals with multiple target data including static displacements, natural frequencies and mode shapes. By applying principal component analysis on identified models, numerous target values and structural model parameters can be grouped according to their relevance and contributions in finite element model updating process. In the identified principal component space, then, a representative model is selected via K-means clustering method. The proposed method is applied to the Yondae Bridge in Korea, a 4x45 m continuous steel-box girder bridge. Analysis results of the application show the proposed method can successfully produce a representative finite element model of which static and dynamic properties are well within the given error bounds of field measured data. Moreover, it shows that structural performance of the bridge can be identified by representative finite element models in terms of deflection, moment and shear force. Rating factor will be calculated to assess structural performance more definitely corresponding updated models’ status.
Extending the fatigue life of welded tubular bridge joints thanks to internal diaphragm stiffening
Authors: Stael Dries , De Backer Hans , Van Bogaert Philippe
Published: May 2013

Tubular arch bridges comprise many welded tubular nodes, which are the most critical parts, since they reduce the fatigue strength of the bridge. Due to geometric discontinuity and the welding process, various stress concentrations are introduced at the nodes, making this type of bridge prone to fatigue damage caused by the varying traffic loads. High peak values of stresses, so-called hot spot stresses, are reached near the weld toe of the nodes. The objective of the present research is to increase the fatigue strength of these nodes or to reduce the hot spot stresses. A possible solution is to provide diaphragms inside the main tube. These diaphragms will reinforce the main tube thus reducing the in-plane deformation of this tube. Calculations show that the diaphragms have a positive influence on the hot spot stresses near the weld toe. The fatigue life of the whole bridge increases considerably due to this reduction of the weld stresses.
Deconstruction of Bridges - New Recycled Aggregates for Granular Layers
Authors: Martinho Fernando , Medeiros Bruno , Matos Gonçalo
Published: May 2013

This article describes the recovery process of one of the "wastes" produced in a big motorway construction project located in Portugal. This by-product was the Construction and Demolition Waste (CDW) and was obtained by crushing the concrete resulted from the demolition of five bridges (all of them were made with pre-stressed concrete) in the existing national road (constructed 20 years ago). In order to fulfil all the parameters required in the technical specifications the crushed material was combined with soils (with some plasticity) from the excavation inside the stretch under reconstruction. The results obtained with this innovative "eco-Aggregate" exceeded the expected specifications and met two of the most important objectives for sustainability: the reuse of available resources and a reduction of the energy consumption.
Mechanical behaviour of concrete piles affected by sulphate attack
Authors: Flansbjer Mathias , Lindqvist Jan Erik , Hanjari Kamyab Z. , Johansson Gabriel , Löfgren Michael
Published: May 2013

Assessing the remaining service life is vital for the planning of maintenance of concrete constructions in aggressive environments. Here we present results from testing of two concrete piles affected by sulphate attack in marine environment. A multi-method approach going from micro scale to structural level has been applied. The crack propagation was monitored during loading by means of DIC and AE. After the test crack patterns was studied using fluorescence microscopy.

Furthermore, non-linear finite element analysis at the structural level was used to study the influence of the chemical attack on the response of concrete piles.
Rapid Calibration of a Damaged Bridge Undergoing Rehabilitation
Authors: Pakrashi Vikram , Kelly Joe , Harkin Julie , Farrell Aiden
Published: May 2013

Redistribution of stresses can be difficult to predict following damage in bridge structures. Such uncertainty is particularly important for designing, monitoring and decision making in relation to repair works. When continuous monitoring is deemed feasible on a damaged bridge, on-site rapid calibrations can be of significant importance in addressing these uncertainties and help in the decision making process. This paper presents a full scale example of a bridge structure damaged by impact loading and subsequently repaired in the presence of a monitoring sensor network. A site- based, rapid calibration of the damaged and undamaged beams in the bridge is presented based on full-scale experimentation and the relationship between the calibrations between the damaged and undamaged beams are investigated.
Optimum Inspection Policy for Long Span Bridge Based on FTA with Visual Inspection Data
Authors: Miyazaki Bumpei , Matsuoka Kodai , Kaito Kiyoyuki
Published: May 2013

This paper proposes a decision making methodology on an optimal inspection method/cycle for long span bridges, based on the two evaluation items: lifecycle cost and risk probability. The authors express the risk of the management limit in the visual inspection of a long bridge with a fault tree, and calculate the probabilities of events constituting the fault tree with the Markov transition probability. Then, it becomes possible to grasp the variation in risk probability due to the difference in inspection policies. Finally, the proposed method is applied to the actual case of determining an optimal inspection policy, to discuss its effectiveness empirically.
The effect of management decision processes on the management of bridges
Authors: Jamali Amin , Adey Bryan T.
Published: May 2013

In order to ensure that bridges continue to provide an adequate level of service it is necessary to perform inspections and execute interventions. Since both inspections and interventions incur negative impacts on bridge stakeholders, it is desirable to determine the optimal management strategy (OMS), i.e. the optimal inspection and intervention strategies to minimize the negative impacts. An important, however often overlooked, factor in determining OMSs, is how the processes used to determine the MS affect the net benefits associated with them, and thus the OMS. In this article it is shown that it is not possible to determine the OMS without explicitly taking management processes into consideration. This is done by showing how variations in the processes affect the MSs to follow, how the effect can be evaluated, and how the significance of the variations depends on the values of the incurred impacts.
Risk-based asset management of a navigation network
Authors: van der Toorn Ad , van der Wiel Wouter , de Rooij Mario , Janssen Hans , Kiljan Dirk-Jan
Published: May 2013

In the Netherlands the State Public Works is responsible for the main waterway network, where locks are mostly the decisive bottlenecks in the navigation corridors. In the last decade the State Public Works has changed from a technical oriented maintenance organization mainly focussed at the component and asset level to a user oriented service provider at the corridor and network level, while the more technical activities at the basis are brought to the market. This radical change will only be successful if the relations between the technical conditions of components at the basis can be linked to requirements at the network level in terms of availability, reliability, etc. To work this out a restricted amount of twenty locks are carefully inspected and bottom-up analysed to assess their present state and to find these vertical relations. Next a set of more generalized findings based on key performance indicators will be rolled out across the whole network in order to rank the risk of the different systems and prioritize inspection and maintenance activities.
Disturbance Indicator Benchmark for Urban Bridge Construction
Authors: Brouwer Jeroen , Vogel Ruben , Thodesen Carl
Published: May 2013

European bridges are today in a state of particular concern with over 50% of European urban bridges being more than 40 years old and thus requiring considerable maintenance or possibly even replacement [1]. This means that interventions in the present infrastructure have to be made while ensuring that mobility continues in a safe and consistent manner. Also the (re-)construction of the bridge has to be completed in a sustainable manner with minimum disturbance to the users and local residents. In order to meet the demand for disturbance friendly construction alternatives, a European benchmark of civil engineering projects was created. Ultimately the solution is the use of a Multi Criteria Decision Model (MCDM) linked with the results of the benchmarking assessment in order to weight the selection criteria for the most advantageous construction alternative possible.
From measurements to prediction of moment of intervention during the (remaining) lifetime
Authors: Voogt Henk
Published: May 2013

The Port of Rotterdam has put considerable investment into the development of models that can identify the best moment to initiate remedial intervention to ensure maximum longevity for steel- concrete quay infrastructures that are in constant use
Major maintenance and strengthening of eight steel arch bridges in The Netherlands
Authors: Blom J. C. A. , Hesselink Bert H.
Published: May 2013

The Weesperbridge is one of the eight bridges in the maintenance project which will be replaced by the Contractor, in a project for major maintenance and strengthening of this steel arch bridges. For the engineering much analyzes should be made. Each analyse expects a FEM model with different level of detail. Analyzes are made of strength, fatigue and stability.

The transportation and installation of the new bridge has its restrictions. So there are the limited height of the other bridges across the Canal and the restriction to obstruct the river for a maximum of eight hours. These restrictions require an efficient and well-prepared method for the installation.
A heuristic model for performance assessment of welded joints in orthotropic steel decks based on monitoring data
Authors: Farreras Alcover Isaac , Andersen Jacob E. , Chryssanthopoulos M. K.
Published: May 2013

Orthotropic steel decks can present fatigue issues at welded joints, the assessment of which turns out to be a complex task due to their intricate geometry, the uncertain nature of the primary live load (traffic flow) and the temperature-driven composite action between the pavement and the steel deck. Current assessment methods tend to disregard the joint effect of traffic levels and pavement temperatures and rely on relatively long-term monitoring periods to capture strain responses and the overall associated uncertainty. This limits the ability to interpret short-term monitoring data, since failure to quantify this temperature-traffic interaction makes it impossible to understand short-term variations in the monitored strain responses. To overcome current limitations, a heuristic model is presented to predict stress-related performance indicators monitored at welded joints in orthotropic steel decks considering pavement temperatures and traffic levels as input parameters. Model parameters are determined through multiple linear regression and can be regarded as the set of health-related features to perform local Structural Health Monitoring (SHM). Model simulations are benchmarked with real monitoring data from the Great Belt Bridge (Denmark). In general, good agreement is found between model simulations and monitoring data. Current research efforts to improve the limitations of the proposed model are outlined.
Crack growth prediction of deck plate-stiffener joints in orthotropic steel bridge decks
Authors: Maljaars Johan , Gration David , Vonk Edo , van Dooren Frank
Published: May 2013

Orthotropic deck structures are used in many steel bridges. Due to the typical detailing applied as around 1970, a significant number of deck structures constructed in that period suffer from fatigue damage. In many countries cracks have been detected, in particular in the weld between the deck plate and the trapezoidal stiffener. These cracks tend to grow relatively slowly, but are difficult to detect at an early stage because they initiate from inside the trapezoidal stiffener.

This paper presents a model with which the growth of these cracks can be predicted. The model is aimed at the growth rate prediction of through-thickness cracks that can be detected by visual inspection, but that do not have a risk of fracture, which would affect the traffic safety. Stresses are extracted from a detailed finite element model of the entire deck. A second, local finite element model including the crack is used as the basis of a fracture mechanics model. The growth rate determined with the model is calibrated and validated with measured cracks in various bridges.

The novel model can be used in daily engineering practice. It can serve to determine inspection intervals for orthotropic bridge decks. It can also serve to support decisions of repairing detected cracks or to determine the effectiveness of strengthening measures such as the addition of a high strength concrete overlay. The model has been successfully applied to 6 large existing bridges in The Netherlands.
Assessment and Strengthening of the Kreekrakbrug
Authors: Karagiannis Demis , Darlow Mark
Published: May 2013

The Kreekrak bridge was constructed in 1974. It suffers from fatigue damage in its orthotropic deck and has insufficient static strength for future traffic loads. It also provides less than desirable clearance to shipping traffic passing beneath it. It therefore requires to be renovated and a combination of applying a high strength concrete (HSC) overlay, jacking and augmentation of the main steel members of the bridge has been designed for this purpose. The sequence in which the renovation is executed has been developed to ensure an efficient strengthening design.

This paper describes the key features of the strengthening design and reasons for its implementation.
Concrete Slabs under a Combination of Loads in Shear
Authors: Lantsoght Eva O. L. , van der Veen Cor , Walraven Joost C.
Published: May 2013

Previous experimental research at Delft University of Technology indicated an increased shear capacity of slabs under concentrated loads as a function of decreasing distance to the adjacent line support. Expressions have been derived for this increase, including the definition of an appropriate effective width. However, it is unknown if the uniformly distributed loads on solid slab bridges, e.g. due to dead loads, that act over the full width can be combined with the effects of concentrated loads acting only over the associated effective width at the support. To study this problem, additional experiments have been carried out at Delft University of Technology, in which a combination of loads consisting of a concentrated load close to the support and a line load over the full slab width are applied. The experimental results prove that the superposition principle applies to combinations of concentrated loads and distributed loads.
Residual shear capacity of 50 years old RC solid slab bridge decks
Authors: Yang Yuguang , den Uijl Joop , Walraven Joost
Published: May 2013

The paper presents a research program dealing with the shear capacity of existing solid slab bridge decks without shear reinforcement. The widely applied design formula in Eurocode regarding beam structures without shear reinforcement is evaluated as a reference. The research program is subdivided into several test series. The research topics include choice of the concrete strength for the evaluation of existing structures, the influence of structural boundary conditions, and the shear failure criterion to be considered. It is concluded that the shear capacity of existing structures can be based on the actual concrete strength derived from core sample tests; for continuous beams, the shear capacity is better defined by the shear slenderness given by the maximum M/Vd in the shear span than by the a/d ratio; the inclined cracking load Vcr is a more robust failure criteria than the ultimate shear load Vu.
Shear failure of 30-year-old aqueduct wall?
Authors: van der Vliet Coen , de Boer Ane , Wolsink Gerrit
Published: May 2013

A 3D linear elastic finite element model has been used for strength reassessment of an existing reinforced concrete aqueduct with shear cracks at suspicious locations. With this relatively simple approach very useful results have been obtained. The observed damage appears to be related to local redistribution of stresses, and the overall structural safety seems to be sufficient. However, appropriate measures have to be taken to avoid degradation of the reinforcement. Additionally, the findings should be supported by e.g. a refined calculation and thorough inspection of the structure. This paper describes the finite element model and the results of the linear analysis.
Assessment of Structural Concrete Members using the ModelCode 2010 Shear Provisions
Authors: Sigrist Viktor
Published: May 2013

In this contribution the fib Model Code 2010 (MC10) shear provisions for members with shear reinforcement are outlined. Furthermore, they are compared to those of the Eurocode 2 (EC2). The Model Code developments comprise two novelties: These include the concept of the Levels of Approximation (LoA) and the dependence of the member's strength on its strain state. The idea behind MC10 is to have a solid basis for the design as well as the structural analysis of members in shear (assessment). Additionally, future developments should be enabled and a framework for this defined. In the comparison of the two codes it is shown that the results are partially in good agreement but deviate from each other in certain ranges of parameters.
Shear fatigue assessment of prestressed concrete bridges
Authors: Teworte Frederik , Hegger Josef
Published: May 2013

Many existing bridge structures were designed in the 1960s and 1970s according to former codes which do not represent the expected traffic loads. These structures typically feature comparable low shear reinforcement ratios and a high degree of prestressing. Their shear bearing capacity was originally determined based on the principal tensile strength criterion and can often not be approved by the strut and tie models of the current code provisions. Within a research programme, fatigue tests on prestressed concrete beams have been performed. This paper gives a short summary of the experimental investigations and the observed shear fatigue failures. Based on the resisted load cycles until failure, modified approaches for shear fatigue in terms of Goodman-Diagrams based on the principal tensile strength criterion have been developed. The application to bridge structures in order to assess the shear strength under cyclic loading is presented.
Diagnosis process for the assessment and the refurbishing of port and maritime existing structures
Authors: Collin Bertrand , Cappelaere Frederic , Jouve Vincent
Published: May 2013

The managers of maritime port structures have to face several issues: ageing of structures, environmental risks, maintenance, adaptation to new equipments and new vessels. The assessment of structures condition is therefore a critical element to help managers to make the proper decisions to ensure a continuous exploitation and to avoid exploitation losses. This assessment is done through a diagnosis which aims to give the objective elements to make the proper choices. After a general presentation, the diagnosis issues are illustrated by the presentation of real studies on a grain dock in La Rochelle and an oil wharf in Guadeloupe Island. In each of these studies, managers’ issues are exposed, and the means and methods used to address them are presented. The conclusions of these diagnoses are then commented, with a focus on linking these specific cases to broader issues and pointing on the difficulties for the assessment and refurbishing of old structures.
Effect of Climate Change on the Deterioration of Steel Bridges
Authors: Kallias Alexandros N. , Imam Boulent M.
Published: May 2013

Corrosion, which is associated with material loss with time, is a widespread cause of deterioration in metallic bridges. If left untreated, increasing corrosion damage may lead to reduced safety, premature in-service failures as well as altered structural behaviour and failure modes. The exposure conditions of the structure, which are determined by environmental and atmospheric parameters, i.e. relative humidity (RH), temperature (T), atmospheric pollution, etc, have a significant influence on the deterioration process due to corrosion. Hence, changes on the exposure conditions of the structure are likely to be responsible for changes on the deterioration process, including the rate of corrosion. In this paper, a reliability based procedure – using Monte Carlo simulation – is developed for the time-dependent risk assessment of corroding metallic bridges, considering explicitly the influence of environmental and atmospheric parameters. Several variables associated with the deterioration process (e.g. RH, T, SO2, Cl) as well as the resistance of the bridge are treated as random using suitable distributions. The potential effect of climate change on bridge risk and reliability is quantified by considering changes in the statistical properties of these variables based on the emissions scenarios of UKCP09. A case study is presented in which a steel railway bridge is used to demonstrate the proposed procedure. Results are presented for the moment capacity limit state for a number of exposure scenarios. The results indicate that for the examined bridge type and location, climate change is shown to have a beneficial (but relatively small) effect on the long term reliability and risk. The parameters with highest adverse influence on deterioration

performance of the examined bridge are shown to be the concentrations of SO2 and airborne salinity.
Hofplein Railway Viaduct (1900-1908): A Pioneering Concrete Structure that Challenges Conservation
Authors: Heinemann Herdis A.
Published: May 2013

The Hofplein railway viaduct (1900-1908) in Rotterdam was once the longest Dutch reinforced concrete structure. Its underlying design is remarkable for its period, as alternatives to then common patented reinforcement systems were sought. Experience with reinforced concrete was still limited. During construction, the design was adapted, leading to a variety of reinforcement systems. Special attention was given to the surface finish, using a combination of natural stone plinth and a tooled artificial sandstone render. The structure is listed as a national monument. Degradation is present, affecting the unique reinforcement and surface finish. Being a monument, additional conceptual conservation requirements would have to be fulfilled during an intervention. In this paper, the relationship between the heritage values, historic fabric, and state of conservation is explored, and the resulting case specific criteria for a possible conservation.
New continuous 3-span concrete railway decks with extradosed post-tensioning cables in widening an existing multiple arch bridge
Authors: De Pauw Bart , Van Bogaert Philippe
Published: May 2013

In improving the accessibility of the capital of Belgium by train, the railway company wants to increase the number of tracks from 2 to 4 tracks for the main railway lines in the direction of Brussels. In the urbanized and densely populated area near the capital, the design of the new infrastructure in extending the tracks, one on each side of the double track line, must be done with respect to existing historic bridges dating from the early 30’s. The paper describes the extension of a 3-span concrete multiple arch bridge over the canal Brussels-Charleroi by two new continuous 3- span concrete bridges with external post-tensioning and a total length of 102 m. The new one track superstructure is a fully concrete deck in U-shape having a width of 6,1 m and is continuous over 3 spans of respectively 30, 42 and 30 meter. Four extradosed post-tensioning cables make the construction a modern concrete structure contracting the existing arches. The paper describes the integral design of the railway bridge and the extradosed post-tensioning, as well as the construction method. In the design, special attention is given to the modeling of the post-tensioning cables taking into account that these cables are free from the deck in horizontal direction. The influence of this modeling on the cable force variation and the friction in the cables is considered. Finally, attention is given to fatigue in the extradosed cables. During and after the construction phase, continuing strain gauge measurements for a long period will be carried out in both the deck and the cables.
Repair and strengthening of the CANOT Bridge in Besançon, France, for the crossing of the First Tramway Line
Authors: Bathelier Philippe , Guth Didier
Published: May 2013

The Canot Bridge is a triple arch bridge, rebuilt in 1949, after WWII. It is located in the center of the city of Besançon, over the Doubs River. The span of each of the three main arches is 27,40 m and the rise is 4,31 m. In the cross section, the structure consists in 3 arches, having a width of 2,20 m and a height varying from 0,80 at the crown to 1,00 m at the spring. The particular point is that the arches are made of concrete with no reinforcement. The deck is supported by the arches by means of diaphragms. Initially, the bridge was supporting one lane in each direction. In 1979, the bridge was widened with an additional concrete cantilever structure, allowing two lanes in each direction. Two lanes will be sacrificed to allow the bridge to carry 2 tramway lines.

The object of the study was to check the structure under these new load cases. One of the issues is that neither any information about the building phases nor the bearing conditions of the arches on the piers was available for the study. This article will present the results and the strengthening works that were decided. Works on site have started in August 2012 and will last until April 2013.
Reconstruction of an arch bridge across Ohře river, Loket, Czech Republic
Authors: Korbelar Jaroslav , Kroupar Miroslav , Ryjáček Pavel , Schindler Jiří
Published: May 2013

This paper describes the design and construction of a unique widening of a concrete arch bridge across Ohře River by using a light steel superstructure. The bridge reconstruction formed part of a wider reconstruction of the road I/6 including its transformation from a two to a four-lane highway near Loket between Nové Sedlo and Sokolov in the North-West part of the Czech Republic. Details about the erection of the steel structure and strengthening of the concrete arch and piers are also given.
Widening of an Existing Concrete Girder Railway Bridge with an Asymmetric Steel Section for an Additional Track
Authors: Outtier Amelie , De Pauw Bart , De Backer Hans , Van Bogaert Philippe
Published: May 2013

The railway line between Bruges and the Zeebrugge at the Belgian coast will be expanded with a third track on one side of the bridge. The railway tracks cross the Bevrijdingslaan, one of the major entrances to the historic city centre of Bruges. The existing bridge has a rather functional outlook: it’s a concrete box girder bridge with a three span continuous superstructure. The two box girders, which are post-tensioned, carry two tracks.

For architectural reasons, a fully integrated design solution is chosen for the widening of the bridge, without structurally influencing the superstructure of the existing bridge. A new asymmetrical steel caisson structure is built adjacent to the existing bridge. The new bridge structure will be continuous over both piers as well. The necessary parapets are part of the bridge and the bridge design also incorporates an acoustic screen and a service pad on the other side of the existing concrete bridge. The new steel caisson has a curved design, which is repeated in the acoustic screen ensuring that the unity between all bridge components is highlighted. This is further realised by integrating the existing piers into the design of the new piers resulting in a more uniform design concept. Due to the incorporating of the old piers into the new piers, the horizontal resistance of the bridge is different, resulting in a redistribution of the horizontal forces. Since the complete structure must be in accordance with the present codes for the railways. Especially, these codes are severe to horizontal movements and forces. Furthermore, the curvature of the bridge is continued into the piers, which ensures not only the unity in design between old and new, but also works as a portal function, creating and inviting entrance to the historic city of Bruges.

The objective of a fully integrated design is achieved, creating a port to the historical city of Bruges. This paper gives an overview of the design considerations of the particular bridge, taking into account the existing boundary conditions, and the corresponding solutions in the final design.
Pont de l’Enfance – Radical facelift for a bridge in Cameroon: Temporary bridge replaced by permanent structure after 35 years
Authors: Vander Meulen Hubert
Published: May 2013

The bridge “Pont de l’Enfance” in Cameroon, originally built between 1977 and 1979, is situated in Koro, between the villages of Sa’a and Ntui, and crossing the Sanaga River there. A two-lane bridge was originally planned. The single-lane bridge crossing the river up to last year was intended as a temporary structure. Over 30 years later, it is still in use.

The Cameroon government has awarded the contract for the refurbishment works turning it into a modern 2 lanes bridge. The refurbishment has begun with a thorough inspection of the foundations (seismic survey), resulting in an injection campaign at the interface with bedrock. The existing superstructure of the bridge has been completely dismantled. On the existing foundations, extensions of piers are then erected, together with abutments capable of bearing a new combined bridge deck. The metal skeleton composed of 34 main bearing girders has been assembled at one bank. The metal structure has been hoisted in one go from to the other bank and was let down onto its final supports. Precast collaborating roadway elements have been installed and connected after launching.

The complexity of the project lies in the fact that the works have to be scheduled according to the water level of the Sanaga River. This is because the piers need to be refurbished and extended in dry conditions. The current bridge deck has been used as a work area, eliminating the need to use waterborne craft to gain access to the site.
Practical Integration of Risk Management and Monitoring During Rebuilding of Subway Station CS Rotterdam
Authors: de Doelder Bert , Berkelaar Robert , Luijten Cor , Thumann Vladimir
Published: May 2013

In the centre of Rotterdam, extensive reconstructing works are executed in the underground subway station CS during the period 2005 – 2011. The goal is to provide sufficient passenger transfer capacity in the future. Rebuilding of the underground station is part of the overall project Rotterdam Centraal. Governing design condition are: regular underground subway traffic, passenger transfer and safety at the existing underground station will not be affected during the construction works.

Risk management, including monitoring of building activities which might affect surrounding objects ( tunnels, high-rise buildings) and implementation of remedial actions, turn out to be an essential part of the project.

This paper describes the process and the results from evaluation of the project's monitoring experience by comparing the design phase (contract specifications) to the construction phase (control of building activities with monitoring results). Within this context the monitoring of some technical project features will be highlighted. Cases on control of groundwater levels and deformation of the existing subway tunnel are presented. Evaluation of the monitoring will be presented, including the lessons learned. It is concluded that the complete risk control and monitoring format as followed by Rotterdam Public Works has proven to be of vital importance for safe and proper execution of construction works in an urban environment.
Brunette River Bridge: New Upgrade, New Constraints
Authors: McIntyre Jamie , Holmes Keith , Gérin Marc
Published: May 2013

The Brunette River Bridge, near Vancouver, Canada, is a four-span, 100 m-long, prestressed concrete girder bridge carrying a major highway and jet fuel pipeline. Originally built in 1963, the bridge was first widened and retrofitted in 1997. Recently, the bridge was upgraded for a second time. Endangered fish habitat constrained the latest widening: unique, post-tensioned cantilevers were constructed to avoid impacting the river below. The original seismic retrofit concept was retained, even though the criteria had changed. Highway traffic and the jet fuel pipeline constrained repairs of corrosion damage to the deck and girders. Corrosion damage often extended beyond the areas indicated in the pre-construction condition survey. Design sought to anticipate potentially unwelcome surprises during construction, and had to react quickly to address the surprises that were encountered.
Structural rehabilitation and lengthening of three 50 year old locks in Limburg, the Netherlands
Authors: Vits Werner , Watzeels Ken , Bourlon Dirk
Published: May 2013

With an ever increasing demand for freight traffic on a congested road network, there is a renewed interest in transportation on inland waterways. However, there has been little investment in waterway infrastructure over recent years.

To meet rising demands for larger vessels and to limit waiting times at locks, Rijkswaterstaat has invested in the enlargement of three locks on the Julianakanaal in the south east of the Netherlands. The lengths of the locks have been increased from 142m to 225m, the structural safety of the existing lockchambers was raised and the mechanical and electrical fittings have been replaced. This has resulted in an increased canal freight capacity.

Following a survey and an initial analysis by Rijkswaterstaat, it became apparent that the locks could be overloaded due to the combined effects of soil pressure from the backfill and cyclic loads from temperature and water level changes inside the locks, this risk was to be mitigated.

This paper provides an overview of the design and build project “Sluizen Limburg” project that was undertaken for Rijkswaterstaat. The paper includes a discussion on the solution to the overloading of the chamber-walls and the analysis and rehabilitation of the existing structures.
East London Line Phase 2
Authors: Place David , Jones Robert , Palmer Ian
Published: May 2013

The paper describes the civil engineering works needed to bring back into use a section of railway originally opened in 1871 as part of the East London Railway providing steam hauled services through Brunel’s Thames tunnel. When the railway was first built, there was a flat junction with the main line, after which the tracks passed beneath a succession of older railway viaducts, climbed up onto a bridge over the Grand Surrey Canal and thence continued on embankment to join the suburban line to Clapham Junction. The train service was withdrawn in 1911 and the tracks dismantled two years later. Fortunately the ownership of the track bed was retained and in the 1990’s proposals could be developed for a southern extension of the East London Line to reconnect with the suburban rail line and so allow trains to run through to Clapham Junction once more.
Humber Bridge A-frame rocker bearings replacement
Authors: Collins John , Hornby Richard , Hill Peter , Cooper John
Published: May 2013

The Humber Bridge was opened in 1981 and carries the A15 dual carriageway over the Humber estuary, UK. From opening until 1997, it was the longest single span suspension bridge in the world with a main span of 1410 m. The deck is discontinuous at the towers where pairs of A-frame rocker bearings control the vertical and lateral position of the deck and provide a torsional reaction to the deck box. Extensive wear to the pin bearings of the main-span A-frame rockers was apparent, hampering their performance. Six refurbishment / replacement options were considered prior to selection of replacement of the A-frames by pendels and a wind shoe. The pendels will be connected to the deck box and tower portal beam at their ends using spherical bearing housed pins offering future durability and maintenance advantages. The wind shoe cantilevers from the deck box end, horizontal reaction provided by opposed hydraulically preloaded sliding bearings.
Port of Zeebrugge – Deepening of Container Handling Zeebrugge quay wall
Authors: Deblauwe Bernie , Sanders Frederik , de Clerck Dirk , van Parys Dieter
Published: May 2013

The Container Handling Zeebrugge quay wall was built in 1962-1970 and was designed for a water depth of 14m. The existing construction is of the “Danish type”, consisting of a concrete relieving floor on driven concrete piles and a steel sheet pile retaining wall. To make the quay accessible for container ships with a draught of up to 18 m a new front (combi-)wall will be erected. Behind the existing relieving floor new vertical tubular piles and MV piles driven at an angle of 50° to the horizontal will be installed. Cast in-situ and post-tensioned concrete beams with a slab on top will transfer the vertical loads to the front and rear tubular piles and transmit the horizontal forces to the MV piles. The corrosion rate of the existing sheet piles has been investigated allowing a structural verification and because of geometrical restrictions the results of a pile test were integrated in the design and this made it possible to reduce the number of piles.
COMPARISON OF AGAR GEL IMMUNODIFFUSION TEST, IMMUNOHISTOCHEMSITRY AND REVERSE TRANSCRIPTION - POLYMERASE CHAIN REACTION FOR DETECTION OF INFECTIOUS BURSAL DISEASE VIRUS
Authors: Islam MT , Islam MN , Khan MZI , Islam MA
Published: May 2013

The objective of this study was to compare agar gel immunodiffusion test (AGID) and immunohistochemistry (IHC) with reverse transcriptase-polymerase chain reaction (RT-PCR) in terms of sensitivity and specificity for the detection of infectious bursal disease virus (IBDV). Thirty-five bursal samples collected from filed outbreak of IBD were evaluated by all 3 diagnostic tests. Sensitivity and specificity of both AGIDT and IHC with RT-PCR was 94.12% and 100%, respectively. Both AGIDT and IHC showed a 94.29% association with RT-PCR with a k value of 0.482, indicating a moderate degree of agreement. The Cochrans Q value was 4.00, which is lower than the critical value, indicating that the methods did not differ significantly (p>0.05) from each other in detection of samples as positive or negative. However, RT-PCR had distinct edge over these two tests employed in the study.DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13452
DETECTION OF AVIAN INFLUENZA VIRAL ANTIGEN IN DUCKS OF HAOR AREAS OF NETRAKONA DISTRICT USING RAPID TEST KITS
Authors: Sarker RR , Rahman MS , Uddin MJ , Khan MAHNA
Published: May 2013

The study was carried out to detect the presence of Avian Influenza (AI) viral antigen using rapid antigen detection kit from free ranged ducks in haor areas of Bangladesh. The cloacal swabs were collected randomly from 20 duck farms of two Upazilas of Netrakona district and a total of 65 field samples were tested in this study. The overall proportion of avian influenza H5 antigen positive reactivity was 6.2% in Netrakona district. The proportion of avian influenza H5 antigen positive reactivity was 6.7% in Netrakona Sadar. Beside in Atpara Upazila, the proportion of avian influenza H5 antigen positive reactivity was 5.7%. In this study, there was no significant (p>0.05) relationship between the presence of AIV in domestic ducks in two Upazilas. This is the first report that successfully detect avian influenza virus antigen in ducks of Bangladesh using rapid test kits. The duck in the haor area could act as a source of AI viruses towards infecting domestic chickens and other free living birds of Bangladesh.DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13454
BACTERIAL PATHOGENS AND RISK FACTORS ASSOCIATED WITH MASTITIS IN BLACK BENGAL GOATS IN BANGLADESH
Authors: Amin MA , Samad MA , Rahman AKM Anisur
Published: May 2013

The objectives of this study were to isolate major bacteria responsible for and to identify the potential risk factors associated with clinical and subclinical mastitis in Black Bengal goats in Bangladesh. A cross sectional study was undertaken on 242 lactating does during January to August 2009. Data on probable risk factors was recorded by using  questionnaire. Clinical mastitis was detected by gross signs of udder infection during physical examination and abnormal milk whereas subclinical mastitis was recognized California Mastitis test (CMT) Milk samples of all clinical and subclinical mastitis goats were subjected to culture for isolation and identification of responsible bacterial pathogens. Multiple logistic regression model using a backward stepwise method was used for identification of risk factors. The overall prevalence of clinical mastitis and subclinical mastitis were 4.54% and 37.19%, respectively. Bacterial pathogens isolated were coagulase negative Staphylococcus (73.73%), Staphylococcus aureus (26.67%), Streptococcus sp. (20%), Bacillus sp. (70%) and Escherichia coli (6.67%). Both clinical and subclinical mastitis were significantly associated with age (p<0.001), parity (p<0.001), lactation stage (p<0.001), litter size (p<0.05) and teat lesions (p<0.001).DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13458
DETECTION OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) FROM ANIMAL AND HUMAN ORIGIN IN BANGLADESH BY POLYMERASE CHAIN REACTION
Authors: Alam MM , Uddin MS , Kobayashi N , Ahmed MU
Published: May 2013

Methicillin-resistant Staphylococcus aureus (MRSA) is defined by the presence of the mecA gene, which is considered to have been transferred horizontally from unknown bacterial species to S. aureus. The mecA gene which encodes an additional ?-lactam-resistant penicillin-binding protein (PBP), termed PBP-2a (PBP-2) with reduced binding affinity for ?-lactam compounds. We investigated distribution of the mecA gene in a total of 94 clinical strains of S. aureus isolated from both man and animal admitted in Bangladeshi medical hospital as well as Veterinary clinic. The mecA gene was detected by PCR in 25% of human clinical isolates of S. aureus, whereas not a single mecA gene was detected in animal isolates of S. aureus.DOI: http://dx.doi.org/10.3329/bjvm.v9i2.13472