bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Optimization and Free form Design
Authors: Majowiecki Massimo , Petrucci Massimiliano
Published: October 2011

Free form design is an important trend in contemporary architecture which aims to overcome the geometric limits of traditional architecture. With the advent of free form design topics like structural efficiency and reliability play a central role in the design process. The adoption of uncommon geometry (often extended in 3D space) make difficult the adoption of classical methodologies for structural analysis. New techiques based on optimization methods can bring a useful contribution in both the architectonic and structural design. In this paper an optimization method based on genetic algorithm is presented and several practical applications are shown and discussed. The complexity due to the large amount of calculations needed by this kind of approach have been exceeded by the adoption of parallel computing strategies that seems to be powerful, scalable with the size of the problem and also valuable from the economic point of view [1].

The present technique can be successfully adopted for sizing and topology optimization of truss structures in real size.
Bond Behavior at the Interface in Concrete Elements Strengthened with NSM Bars and Strips
Authors: Bilotta Antonio , Ceroni Francesca , Di Ludovico Marco , Nigro Emidio , Pecce Marisa
Published: October 2011

The paper presents the results of monotonic Single Shear Tests (SST) on concrete prisms externally reinforced with basalt, glass and carbon bars and strips according to the NSM technique. The experimental tests are a part of wide Round Robin Test programme involving several worldwide research laboratories. The tests are aimed to define the ultimate load and characterize the bond behaviour of different NSM strengthening systems at varying several parameters (material, geometry, surface treatment).
Monitoring Based Evaluation of Design Criteria for Concrete Frame Bridges
Authors: Wendner Roman , Strauss Alfred , Bergmeister Konrad , Frangopol Dan M.
Published: October 2011

Concrete frame bridges (CFB) are characterized by integral abutments associated with the lack of bearings and expansion joints. These reinforced concrete structure types have several advantages in comparison with traditional structures mainly based on maintenance and inspection considerations. However, currently there is little experience concerning this type of design in Austria thus leaving designers with a lot of uncertainty regarding general design principles, appropriate modeling, necessary load cases and structural detailing. In consequence, research projects were initiated with the goal to (a) monitor structural response of real structures, (b) verify current design assumptions and finally (c) derive recommendations for a future guideline. Within this paper a case study is presented focusing on the observation of the soil structure interaction.
In situ tests on steel deck concrete composite slabs at Zurich Airport
Authors: Knobloch Markus , Klippel Michael , Fontana Mario
Published: October 2011

This paper presents an experimental study on composite slabs with profiled steel sheeting (Holorib 51) performed at Zurich Airport in conjunction with the conversion of Dock B. The

structure was built in 1974 with composite floor slabs, a steel frame with stub-girder beams and hot- rolled steel columns as supporting structure. The experimental investigation focused on the bond behavior of the composite slabs and the influence of the 35 years service life.

Ten large-scale tests were carried out on simple beams with different shear span length to evaluate the shear capacity. In addition, tests on two-span beams and cantilever beams were performed. The slab beams were cut from the slab and tested in situ. The data generated by these tests enabled the assessment of the slabs. The paper presents the results of the tests on simple and continuous beams and the evaluation of the results with common design methods.
Performance-based Analysis of Steel Structures with Semi-rigid Connections
Authors: Popa Anca Gabriela , Mathe Aliz Eva
Published: October 2011

The behaviour of steel frames is highly influenced by the way in which the beam-to-column connection is accomplished. For quite some time now, traditional design has regarded such connections as being either perfectly rigid or perfectly flexible (hinges), thus the calculation being developed starting from this assumption.

The paper aims to develop the theoretical concepts that are needed to include the characteristics of semi-rigid connections in the geometrical nonlinear approach. The analysis uses the finite element method and fundamental relationships are inferred by the separate and independent introduction of static, kinematic and constitutive conditions to be met.

Relevant numerical examples are given and discussed. Conclusions regarding the effect of semi- rigid connections upon the performance of steel frames are formulated in the final part of the article.
Research on the Collision Force between Ships and the Piers of Fengjie Yangtze River Bridge
Authors: Zhang Qiu-Ling , Xiao Guang-Hong
Published: October 2011

In this paper, the accidents of ship striking against bridges and the current collision force calculation models have been introduced firstly, then based on Fengjie Yangtze River Bridge, the different model results are compared, which provide guild for the future research as well as design.
Parametric Evaluation of Seismic Damage on Curved Highway Viaducts under Near-fault Earthquakes
Authors: Mendez G. Carlos , Hayashikawa Toshiro
Published: October 2011

This paper investigates the effectiveness of the use of seismic isolation devices on the overall 3D seismic response of curved highway viaducts with an emphasis on expansion joints. Furthermore, an evaluation of the effectiveness of the use of cable restrainers is presented. For this purpose, the bridge seismic performance has been evaluated on four different radii of curvature, considering two cases: restrained and unrestrained curved viaducts. Depending on the radius of curvature, three- dimensional non-linear dynamic analysis shows the vulnerability of curved viaducts to deck unseating and joint residual damage. In this study, the efficiency of using LRB supports combined with cable restrainers on curved viaducts is demonstrated, not only by reducing in all cases the possible damage, but also by providing a similar behavior in the viaducts despite of curvature radius.
Perimetral Joint Effects on Stress Distribution and Seismic Behaviour of Arch Dams
Authors: Mirzabozorg Hasan , Hariri M. Amin , Amirpour Amin
Published: October 2011

In the present study, effect of pulvino and its perimetral joint on stress distribution within dam body is investigated. Dez dam with 203m height is selected as case study and all the contraction joints of the dam body are modelled using discrete crack approach. The reservoir is assumed compressible and the foundation is modelled as a mass-less medium. The system is analyzed under static loads taking account for stage construction effects, hydrostatic loads and thermal loads taking into account the effect of sun radiation. At last, the FE model is excited using MCE earthquake records. It is found that when the perimetral joint between the saddle and the dam body is modelled, the direction of the principal stresses and their distribution patterns are changed and the safety of the system is improved. In addition, over stressed surfaces on the faces of the dam body decreased in comparison with the model without the perimetral joint.
Innovative Methods for Railway Steel Bridge Remaining Life Estimation
Authors: Pipinato Alessio , Gueli Marco , Pellegrino Carlo , Modena Claudio
Published: October 2011

Assessment of remaining life of railway steel bridges is a key issue in order to manage a relevant stock of bridges built between the last 18th and the one half of 19th. Historical traffic usually changes in patterns, volume, and any degradation of structural components can influence the fatigue life of the bridge. For these reasons, innovative methods on evaluating remaining life of steel bridges are required, in order to give to owners precise indications of bridge intervention priority along the network. In this paper, an innovative method is presented: it is based on the precise historical traffic estimation and on a modified Miner's rule. The methodology is then applied on an actual case study. Stress data from critical structural members were used to estimate the remaining fatigue life of selected bridge components. The results indicate that most of the identified critical details seem to have a very long remaining safe fatigue life and others have a limited fatigue life.
Long-term Prediction of Bridge Element Performance Using Time Delay Neural Networks (TDNNs)
Authors: Lee Jaeho , Blumenstein Michael , Guan Hong , Loo Yew-Chaye
Published: October 2011

A bridge is principally designed to have a long service life. However, due to number factors, it could fail prematurely, and could cause loss of human life. In order to ensure the optimum bridge serviceability, systematic asset management is essential for effective decision-making of maintenance, repair and rehabilitation (MR&R). Systematic asset management can be achieved by a computer-based bridge management system (BMS). Successful BMS development requires a reliable bridge deterioration model, which is the most crucial component in a BMS. Historical condition ratings obtained from biennial bridge inspections are a major resource for predicting future bridge deterioration via BMSs. However, available historical condition ratings from most bridge agencies are very limited, thus posing a major barrier for predicting reliable future bridge performance.

This paper presents the progressive research on the development of a reliable bridge deterioration model using advanced Artificial Intelligence (AI) techniques. The development is organised in three major steps: (1) generating unavailable past bridge element condition ratings using the Backward Prediction Model (BPM) - this helps to provide sufficient historical deterioration patterns for each element; (2) predicting long-term condition ratings based on the outcome of Step 1 using Time Delay Neural Networks (TDNNs); and (3) improving long-term prediction accuracy of Step 2 by employing Case-based Reasoning (CBR). This paper mainly focuses on the first two steps of the research. Promising results are reported for the reliable long-term prediction of bridge element performance.
Indirectly Supported Bridges – Large-Scale Experiment
Authors: Bueeler Christoph , Thoma Karel
Published: October 2011

For concrete bridge structures, the currently valid Swiss code, SIA 262:2003 X[1]X, stipulates that in case of indirect support conditions, force transfers need to be checked utilizing stress fields. This is necessary to guarantee that sufficient hanger reinforcement is provided in load application areas. If the total shear force is supported by hanger reinforcement, it is possible to investigate static actions in the longitudinal and transverse beams independently of each other; otherwise, the load bearing capacity depends on the interaction between the longitudinal and transverse beam X[2]X.

In order to investigate the influence of insufficient hanger reinforcement on the strength of indirectly supported beams, a large-scale experiment was conducted at the University of Applied Sciences and Arts, Lucerne X[3]X. The prestressed test specimen reflected a continuous, single celled box girder in the region of continuous support. The experiment clearly illustrated that the ultimate load and the failure mechanism of an indirectly supported concrete structure strongly depend on the reinforcement arrangement and the detailing. Furthermore, the deformation capacity of the plastic hinge also largely depends on the reinforcement arrangement.
Offshore floating platform for renewable wind energy
Authors: Comand Dario , Cosentino Nicola
Published: October 2011

Floating and semi-submerged structures are the forefront of current studies in recent years. Research is aimed at investigating the technical and economical feasibility of such concepts in the deep offshore. The currently proposed solutions for offshore wind energy are mainly based on the petroleum offshore technology. In particular, for deep waters, classical tension leg platforms have been proposed, however weights and costs are not competitive for wind energy.

In this paper, an innovative supporting platform for wind turbines (patented in Italy), optimized for deep waters (but also suitable for shallow ones) will be presented. The supporting structure is made by a semi-submerged space frame and the buoyancy-anchoring system is obtained by appropriately combining light and relatively low-cost technologies already used in other fields. Two different solutions are proposed.
Failure Analysis of a Long-Span Pre-Stressed Concrete Box Girder Bridge
Authors: Shi Xue-fei , Ruan Xin , Li Xiaoxiang
Published: October 2011

In recent years, there have been some certain accidents happened during the construction of continuous pre-stressed concrete box girder (rigid frame) bridges that the upper and lower concrete along the ducts in bottom slabs has been generally destroyed during the tension process of the closure pre-stressed tendons. With the precise numerical analysis of the destruction mechanism of bottom slabs considering the material non-linearity, this paper reproduces the failure process of a typical accident, and analyzes the mechanism of the occurrence and the path of cracks on bottom slabs and the function of vertical tie bars in bottom slabs. Here the method of test analysis has been firstly used in the research of the destruction mechanism of bottom slabs of the depth-variation box girder to further verify and improve the knowledge of the destruction mechanism of bottom slabs and the function of vertical tie bars in bottom slabs.
Eco-sustainable reuse of “Costantinopoli” quarry in Sala Consilina
Authors: Lembo Filiberto , Marino Francesco , Casale Nunzia
Published: October 2011

“Costantinopoli” quarry is located in the hearth of “Vallo di Diano” in the Province of Salerno. The reuse of abandoned quarries in the “Vallo di Diano” is aimed to define a number of small “environmentally friendly” projects in order to counterbalance the current environmental impact.

The project provides a “new green economy” through the development of abio-agriculture, abio- factoryand aeco-sustainable researchand combines ecology, horticulture, science, art, architecture and traditions of “Vallo di Diano”.

The scheme is composed by five areas:the Greenhouse,the Visitors Centre,the Lake,the Tensile Structureandthe Outdoor Biome. It is aimed to educate visitors about the importance of a sustainable environment through the study of plants and sustainable strategies. The solution were inspired by looking through nature, fractal geometry and the landscapes of the site.
Recent Advances in Dynamic Testing and Continuous Dynamic Monitoring of Large Bridges
Authors: Cunha Álvaro , Caetano Elsa , Magalhães Filipe , Grillaud Gérard , Flamand Olivier , Brownjohn James
Published: October 2011

This paper shows the current potential of Dynamic Bridge Testing techniques by presenting recent applications developed at the Millau Viaduct (France) and at the Humber Bridge (UK), and stresses the usefulness of Continuous Dynamic Monitoring, by describing fully automatic implementation in two recently constructed bridges in Portugal (Infante D. Henrique Bridge and Pedro e Inês footbridge, controlled with TMDs), enabling not only the automatic issuing of alert messages whenever some undesirable threshold is exceeded, but also vibration based damage detection using natural frequency shifts, after removing the influence of factors like temperature and traffic intensity on the modal properties.
Impact of New Design Codes on Assessment and Redesign of Reinforced Concrete Existing Structures in Seismic Regions
Authors: Dan Sorin , Bob Corneliu , Badea Catalin
Published: October 2011

Theoretical aspects on the risk assessment of the reinforced concrete structures are presented. The earthquake capacity ratio is analysed for reinforced concrete framed structure. More attention is paid to the seismic shear force capacity and some new procedures are introduced to estimate the earthquake capacity of existing structures.

The present seismic design and assessment of existing structures are done in Romania by using new codes in agreement with the Eurocodes. The impact of these new design codes in comparison with the previous codes is presented for reinforced concrete structures.

The assessment and rehabilitation were performed on a office building RC framed structure built in 1971. The assessment of in-situ conditions showed up the main problems of the RC structure which consisted of inadequate concrete strength at some columns. The strengthening solution consisted in transversal confinement with composite fibre reinforced polymers of the columns.
The Confidence to Build
Authors: Harvey Bill
Published: October 2011

The author acts as a consultant of last resort on arching structures, chiefly in the UK. He has been involved on the periphery of a number of major infrastructure projects where interaction with historic structures has been an issue. Mostly, this work is in unlocking restraints that have been imposed as a result of lack of understanding. Modern computer analysis is very demanding of knowledge, skill and time. Developing analytical skills seems to develop a corresponding belief system that the computer knows better than the structure, but any analysis is only as good as its input. The input requires understanding of:

The analytical tools

The likely behavior of the structure

The interaction of what can be modeled and the real behaviour The values and confidence levels of the input

The values and confidence levels of the output.

If any of these is missing, the results are unlikely to be useful. Unquestioning confidence in the output of analysis may lead to either grossly un-economic or even dangerous designs.

The paper discusses a number of examples where complex analysis has yielded false results. Most often this is because the model constructed falls far short of representing the real structure. Each example is tested against the fundamental principle of statics, that every force must be traced from point of application to an adequate foundation, while remembering that “every structure is a system of interconnected stiffnesses” (Happold).
Integral bridge abutment - approach embankment interaction
Authors: Kerokoski Olli , Petursson Hans
Published: October 2011

The study deals with the development of long jointless bridges with a focus on soil–structure interaction. The instrumentation of Haavistonjoki Bridge was completed in the autumn of 2003. The data were collected by monitoring altogether 191 gauges installed in the bridge structures during construction. The instrumentation was used to measure, for instance, the abutment's horizontal displacement, abutment rotation, abutment pile strains, earth pressures behind abutments, superstructure displacements, frost depth, and air temperature. Haavistonjoki Bridge is a 56 m long continuous 3-span slab bridge. The measured earth pressures were compared with calculated pressures. The bridge over Leduån is a single span composite bridge. The cast-in-place concrete deck acts together with two steel beams. The 40 m span bridge is very slender with the height of superstructure 1.7 m. Totally 34 measurements were constantly recorded and stored in a period of at least 18 months. The bridge over Edslan has a 19.8 m span and a 7.65 m wide concrete slab. The test results are verified with calculations.
Second Bay of Cadiz Bridge-Latest Construction Challenges
Authors: Escamilla Manuel , Martin Marcos , Cayetano Julio , Castillo Alejandro , Osborne Gonzalo , Jimenez Victor
Published: October 2011

The construction works for the New Cadiz Bridge started in April 2007 and the completion is scheduled for autumn 2011. By now, important challenges have been faced, such as the construction of 495 deep piles both inland and on sea, which has demanded innovative excavation solutions. The semi-submerged pier and tower bases have required composite steel-concrete watertight caissons of 1200 tons maximum weight, built inland and placed on site with heavy lift floating sheer-legs, to face the action of the 7 m-high water column, waves and ocean currents. Finally, the rising of the east tower is being developed with a climbing system in the first vertical phase, combined with a complex three-dimensional steel structure anchored to the tower to support the scaffolding of the highly inclined diamond-shaped second phase (only 41º above the horizontal line).
Structural Performance of RC Beams Strengthened by SRG and FRCM System
Authors: Bencardino Francesco , Ombres Luciano
Published: October 2011

This paper presents the results obtained from an experimental investigation carried out on full-size reinforced concrete beams, which are strengthened in flexure and flexure/shear using different external reinforcement systems having an inorganic matrix, such as SRG (Steel Reinforced Grout) and PBO (Polyparaphenylene Benzobisoxazole) FRCM (Fiber Reinforced Cementitious Matrix).

In order to study the effect of the external composite reinforcement, variations in the number of applied layers and in the external end arrangements were made. All beams were extensively instrumented and tested under four point bending.

The performance of the strengthened beams, in terms of strength and ductility, was evaluated and compared with the control beam to highlight the main parameters that affect the mode of failure and the global behaviour of the structural elements.
Bridge Management by Modelling, Monitoring and Experimental Research
Authors: Bosma Carlos F. , Galenkamp Hessel F. , Obladen Bas , Van Breugel Klaas , Koenders Eddy A. B.
Published: October 2011

The traffic intensity in the Netherlands has grown rapidly during the past decades. To effectively manage the infrastructural network, many existing constructions are reconsidered to check for structural safety and future capacity. Effective asset management requires insight in the short and long-term behaviour of civil structures.

The “Hollandse bridge” in the Dutch highway A6 was upgraded with a concrete overlay in 2008. Strukton Civiel performed, in association with Delft University of Technology, a research that investigated the effect of traffic induced vibrations on the hydration of early-age concrete. The motive lies in the uncertainty if vibrations cause degradation of young concrete versus conservative guidelines on civil works. As a consequence, these safe approaches result in temporary detours during maintenance, causing vast traffic disturbances. To investigate necessity, the research combines theoretical vibration analysis with monitored responses of the Hollandse bridge as input for laboratorial research on the degradation of concrete loaded with traffic induced vibrations.
Dynamical Tests and Analysis
Authors: Vestroni Fabrizio , Benedettini Francesco
Published: October 2011

Francesco Benedettini born 1956, Civil Engineering degree Padua 1979, is Professor of structural engineering at the Univ. of L’Aquila. Main research interests are nonlinear dynamics, modal and structural identifications, full scale dynamical tests.

The assessment of the structural conditions of bridges managed by Local Public Territorial Authorities is analyzed in this work. The results of a campaign of repeated modal tests and a parallel program of visual inspections on a class of 100 bridges are reported. The tests and the analysis is used to rate the structural integrity of different classes of the analyzed bridges and to accordingly propose a maintenance program. Relevant case studies are reported to enlighten and discuss particular observed dynamic phenomena in arch bridges.
Structural Assessment of ASR/DEF-Affected Bridge Bent Caps
Authors: Deschenes Dean , Bayrak Oguzhan
Published: October 2011

As part of a large-scale experimental study of ASR/DEF-affected bridge bent caps, the accuracy and conservatism of two structural assessment techniques were examined. The crack width summation and elastic rebound techniques were selected for their potential to provide fast, sufficiently accurate estimates of the expansion due to ASR/DEF. These expansion estimates are ultimately valued for their ability to provide clear insights into the behaviour of affected structures. Comparison of the estimates with measured expansions revealed that the crack width summation technique was best suited to the estimation of moderate expansion levels (above 0.2 percent). Conversely, implementation of the elastic rebound test resulted in excellent accuracy at low levels of expansion (below 0.2 percent). It is believed that further refinement of both techniques could lead to an invaluable pair of techniques for the practical assessment of ASR/DEF-affected structures.
Application of Tuned Mass Control Systems for Earthquake Protection
Authors: Meinhardt Christian , Siepe Daniel
Published: October 2011

The following paper introduces the practical application of Tuned Mass Control Systems (TMCS) for earthquake protection. Optimization approaches for these passive control systems will be discussed as well as practical considerations regarding the resulting specification of the TMCS such as stiffness loss during an earthquake and wide-band effectiveness. For the discussion, theoretical approaches will be introduced and results of additional numerical calculations will be presented to verify the reduction due to the control systems. The contribution also introduces the practical application of TMCS at an elevated bridge structure and presents design solutions for these systems.
A case study of a building in L’Aquila, Italy for evaluating the effects of masonry infills on the seismic behavior of r.c. frame structures
Authors: Trombetti Tomaso , Landi Luca , Silvestri Stefano , Gasparini Giada , Ricci Ilaria
Published: October 2011

It is known that the seismic response of a structural system is highly influenced, in addition to the earthquake input, by the dynamic characteristics of the system itself. It has been observed during the L’Aquila earthquake that some buildings have shown unexpected good performances. The aim of this paper is to understand why these structures, designed for accelerations lower than those recorded during the L’Aquila’s earthquake, have shown performances higher than the design ones. The attention is focused on a real case study of a reinforced concrete frame building structure located in L’Aquila. The paper investigates the role of the masonry infills which, before reaching their ultimate capacity, allows to avoid significant structural damage and excursion in the inelastic range. The seismic behaviour of the examined building is studied within Performance Based Seismic Design approach. In particular, by imposing the performance objectives, an “objectives curve”, in the Force-Displacement diagram related to the mechanical characteristics of the structure, is obtained. Both the contribution of the columns and the masonry infills are considered in the evaluation of the Force-Displacement diagram. Then, time-history analyses are performed by applying to the building under study recorded ground motions of the L’Aquila earthquake. A non linear model of the structure, and in particular of the masonry infill, is implemented for the analyses. The examined response quantities are bending moments and chord rotations of columns and beams as well as forces and deformations of masonry infills. For comparison purposes two cases are studied: the first is the bare frame, the second is the infilled frame. These analyses allow to identify the effects of the masonry infills on the response of the case study.
Design Assisted By Wind Tunnel Testing
Authors: Majowiecki Massimo , Cosentino Nicola
Published: October 2011

According to principle of the “design assisted by testing”, contemplated by the Eurocode, the combination of tests and calculations is increasingly used. The motivation of this increasing interest-demand are various: from the sophisticated architectural shapes to the absence of corresponding reliable fluid-dynamics models, from the increasing flexibility of structures to the necessity of checking complex aeroelastic phenomena.

The purpose of the paper is to outline the potentiality of wind tunnel testing and the main problems encountered in their use. These aspects have to be accurately evaluated in defining the tests specifications. The use of some data analysis techniques (such as the proper orthogonal decomposition, the sensibility analysis, etc.), in keeping the essential design parameters, is presented too.
Two large bridge projects in environmentally constrained areas
Authors: Reis António
Published: October 2011

In large infrastructure projects a variety of environmental constraints may influence bridge design options. Two main recent bridge projects, underway in Portugal, in which the author´s design office has been involved, are discussed.
Toward 21st Century Bridge Design through Collaborative Design Process
Authors: Hong Namhee K. , Koh Hyun-Moo , Hong Sung-Gul
Published: October 2011

Nowadays when structures are defined by their unique forms, innovative use of materials, context- sensitive integrity that create dramatic points, they are acknowledged to be world-class designs. It is very difficult to design bridge structures that offer so manifold rewards, which demands a new set of design environment in which multi-disciplinary experts collaborate each other. Above all the issues to address to develop new design environment, a strategic coordination among architects and engineers might play a key role to elevate modern bridge design to an artistic level. This paper has focused on how the common platform is being evolved for a true collaboration for architects and engineers toward new design paradigm for 21st century bridge design. In association with the collaboration work, a new Silkworm pedestrian bridge was studied as a representative case that was completed through a strong collaboration between artists and engineers as well as community agent. A collaborative design process was developed based on this study. It is expected that architects and engineers can get together through the proposed design platform from conception to completion to create a powerful and efficient structural system and form as well.
A New Steel Arch Bridge in the City of Padua
Authors: Caobianco Francesco , Zanaica Luca , Zanon Roberto
Published: October 2011

The municipality of Padua has recently achieved an important goal, namely the project for the new Fair Bridge. Located in the North side of the city, the bridge wants to be also a comfortable and pleasant gate for pedestrians and bicycles. The main crossing is a steel double arch bridge; the steel- concrete composite deck accommodates the road lanes on transversal cantilevers hanging from the stays, whereas the wide pedestrian boulevard is placed between the skew planes of the arches.

Furthermore, the separation between the different areas is filled with continuous flowerbeds, an ideal extension of the park to the city. After the main span over the railway area, the road lanes split on two different slender box girder steel bridges. The whole process of design was carried out in a very short time, and was constantly kept in touch with the national railway company RFI in order to take into account the many requirements coming from the criticality and importance of the position.
3.2km Precast Segmental Constructed Viaduct - Viaduct V5c, Gautrain Rapid Rail Link
Authors: Burke Rowland
Published: October 2011

The Gautrain Rapid Rail Link is a state-of-the-art rapid rail network currently under construction in Gauteng, South Africa. Viaduct V5c is a 3,2km long segmental construction and is mostly founded in material overlying dolomite bedrock.

The route for viaduct V5c is generally underlain by dolomitic ground with occasional syenite intrusions. The area is well known for the risk of sinkhole and doline formation due to the erodibility of the in situ soil. Sinkholes inherently pose a risk to the rail service and (if left untreated) may potentially have catastrophic consequences.

This paper will reflect on the considerations behind the choice of structural type and associated construction method. The paper will focus on the key aspects pertaining to the final geotechnical solutions & structural design, associated with viaduct V5c.
Bearing behaviour of biaxial hollow core slabs
Authors: Abramski Marcin , Albert Andrej , Nitsch Andreas , Schnell Jürgen
Published: October 2011

Two way hollow core slabs with void formers between the upper and lower static reinforcement are getting more and more popular in Germany. The reduction of the dead load of the slab resulting from the cavities allows larger spans compared to solid slabs with the same depth. Since the void formers are spherical or ellipsoid shaped the slab maintains its biaxial strength. However some open questions regarding the bearing behaviour of two way hollow core slabs still prevent a wider spread of these innovative structural elements. The goal of this research project was to answer these open questions.

While the bending strength of a two way hollow core slab is almost the same like for a solid slab its shear strength is significantly smaller. Therefore in this research project the shear strength of two way hollow core slabs was investigated. 13 large scale tests and corresponding nonlinear finite element calculations were conducted to prove that the shear strength of a two way hollow core slab is at least 50% of the shear strength of an equivalent solid slab.

Another open question was the stiffness of the slab in arbitrary directions which leads to the question whether the internal forces of a two way hollow core slab should be determined like they are determined for a solid slab or rather like they are determined for a ribbed slab. The test and the nonlinear finite element calculations of this research project have shown that it is correct to calculate the internal forces of a two way hollow core slab in the same way like they are calculated for a solid slab.
The properties of arches under loading especially for historical buildings
Authors: Tabrizi Mohamad Hossein Maleki , Bigdeli Ali Akbar
Published: October 2011

Some ancient iranian monumental buildings, mosques and another historical structures which had built in various zones in iran present the covering structure carried by a system of round arches, built up adopting multiple-leaves masonry technology. Buttresses resist to the lateral thrust of the arches. But tresses can undergo significant displacements such as a strenght member of structure. As a consequence, the geometric features of the arches are modified, and many cracks open. The global static conditions of the structure are compromised, especially when there are losses of contact and even local separations between the masonry leaves of the arches, as it can be observed in. this paper presents the results of a numeric modelling of an arch assumed with reference to these structures, the results indicate the progressive loss of bearing capacity due to the buttresses displacement and the worst contact characteristics of the layers. Also some possibilities for future development about using of arches in structures are listed at the end.
Aesthetic Design for the Shi-cong Viaduct
Authors: Hu Zhi-Jian , Hu Zhao-Fang
Published: October 2011

Bridge aesthetics is both elusive and complex, and the lack of an effective and efficient determination for the major aesthetic dimensions of structures has made it impractical to conduct research on bridge aesthetics. Conventional design of viaducts does not question the goals of the selected plan and can mainly meet short term demands in traffic, taking careless of their other functions like aesthetics. According to the viewpoint analysis for viaduct aesthetics, this paper focused on the structural parameters for bridge aesthetic design, i.e. superstructure cross-section, span length, pier height and shape, and column numbers of pier bodies. Then four schemes were offered with aesthetic concerns for the Shi-cong Viaduct and Scheme 3 was finally chosen to be the very one in light of feasibility and aesthetics.
Spatial Concrete Plate Structures
Authors: Gianoli Andreas , Kunze Matthias
Published: October 2011

Spatial concrete plate structures are a classic example of a fruitful interdisciplinary dialogue between architect and structural engineer. Few other construction types enable such a comparatively complete fusion of architecture and structural engineering. The planning process of two selected properties are illustrated from design to execution, and the areas of interdependence shown. This involves presenting the architectural boundary conditions as well as describing the development of the loadbearing structures. Special reference is made to problems raised by dimensioning the structures and the special requirements of execution.
Applications of FRP Projects in Egypt
Authors: Hosny Abdel-Hady , Abdelrahman Amr
Published: October 2011

Advanced Composite Materials, (ACM), have been used in civil engineering applications in Egypt over the last two decades. Significant progress has been made in the use of ACM in the form of fibre reinforced polymers, (FRP), to repair, rehabilitate and upgrade aging or damaged structures. Egypt has released its national code for design and application of FRP in construction fields addressing both externally bonded and internal FRP reinforcement in concrete elements. As a result, the use of FRP for repair, strengthening and retrofitting of structures have become a very well accepted practice in Egypt. The code has been issued after a series of successful rehabilitation projects and extensive studies at different research institutions in Egypt.

This paper highlights the Egyptian FRP code, which was approved by the Egyptian Authorities in December 2005 and became the first formalized design code addressing FRP in Egypt. In addition, field applications of FRP strengthening of special structures in Egypt are also presented. The paper presents selected projects utilizing ACM in the form of externally bonded FRP laminates to strengthen existing reinforced concrete structures. Historical buildings such as the Egyptian Museum and Kaitbay Fence were rehabilitated after distress/deterioration caused by corrosion of steel reinforcement and lack of maintenance. Strengthening of the dolphin piles in Abou-Kier harbour is also reported after cracking occurred due to ship hit. Design concepts and constructional details are presented for each project.
Tausendfüssler and Brückenfamilie in Düsseldorf, (1950-1976)
Authors: Milan Andreina
Published: October 2011

The redevelopment of a city road network from a logistic and technological point of view often means to clash with huge economic and financial interests and to disappoint citizens’ expectations. C (capital city of North Rhine-Westfalia region – Germany) is the emblematic case of an unresolved conflict that was brought about in 1961-62 with the construction of the elevated road called “Tausendfüssler” (the millipede).The difficult relationship between this structure, its complex functional requisites and the traditional image of the city has now led to the decision to demolish the road. As a result, one of the most significative examples of post-war German engineering is bound to disappear.
A Strategy for Modelling External User Element in ANSYS: the Bouc-Wen and the Skyhook Case
Authors: Domaneschi Marco , Martinelli Luca , Romano Michele
Published: October 2011

Literature is rich of control devices modelled by the Bouc-Wen model, like magneto-rheological dampers, metallic dampers, rubber bearings, electro-inductive devices often used in bridge engineering. The ability of such model in the simulation of control systems with different characteristics (like passive, semi-active and hybrid) returns it to be very attractive in a multipurpose framework.

The ANSYS environment allows for implementing user elements in Fortran subroutines, compiling a new executable file; however, this requires the user to: a) understand the interfacing routines provided with the ANSYS code; b) to correctly guess how the interfacing routines will be actually called by the ANSYS environment.

This burden can be avoided by exploiting the APDL (ANSYS Parametric Design Language) command SYS, which allows to call an external executable program from within the main ANSYS analysis procedure, or from within an APDL subroutine. The main idea is to pass quantities of interest (e.g. nodal displacements, velocities, etc.) to the external executable program via an intermediate data file written by standard APDL commands. The external executable replies with some computed quantities (e.g. nodal forces) in a second data file that will be read, processed and applied to the structure by APDL statements. It is worth underline that this implies a decoupling between the process of achieving a structural equilibrium configuration and that of the state determination of the external element.

The usefulness and the limits inherently with this strategy will be shown with reference to the implementation of a new external non-linear element devoted to modelling passive (Bouc-Wen) and semi-active (Skyhook) control devices; these will be used in companion papers for the control of a bridge structure under seismic and wind loading. The external user element is finally evaluated by a comparison with a proven implementation inside the MATLAB environment, which explicitly considers the coupling between the structural state determination and that of the external element, with reference to seismic excitation.
Experimental study on effect of corrosion-induced cracking on bond property between deformed steel bar and concrete
Authors: Wang Lei , Ma Yafei , Zhang Jianren
Published: October 2011

In order to investigate the influences of cover cracking due to corrosion expansion on the bond behaviour between the reinforcing bar and concrete, the pullout test on the bonding specimens with deformed steel bar was designed. The strain gauges were fixed in the interior of deformed steel bars. The accelerated corrosion tests by applying a constant electrical current to the bars by a power supply were used to compare the results that experienced in real RC structures. The reinforcement strains at various positions in bonding specimens with various corrosion-induced cracking widths are obtained. The present study analyzes the effect of corrosion cracking width on strain of reinforcement at different positions. As a result, the bonding stresses at various positions between the reinforcement and concrete are obtained. This paper also develops the relationship between the corrosion cracking width and bonding stress between reinforcement and concrete. The experimental results show that for the specimens with the narrow crack the peak bond stress mainly appears near region of the loading end，however for the specimens with the wide crack the peak bond stress is close to the free end.
The Importance of Dynamic Effects in Progressive Collapse
Authors: Janssens Victoria , O'Dwyer Dermot
Published: October 2011

This paper presents a methodology to assess the extent of damage to a multi-storey structure following localised collapse. This is accomplished through the design of an algorithm to track progressive collapse in a structure and its implementation as a computer program. The algorithm is based on the alternative path method of analysis. Individual elements are systematically removed from the structure, and these altered structures are analysed to determine the extent of the resulting collapse. By considering the effects of damage to all members in a structure the algorithm can identify whether a structure is unduly sensitive to the effects of localised damage. In order to accurately model the progression of collapse through a structure, it is necessary to consider dynamic effects. The algorithm is extended to include dynamic effects and calculate the corresponding increased bending moments and shear forces.
Transparent Façade Solutions with Bonded Glass-Steel Beams
Authors: Weller Bernhard , Meier Anja , Weimar Thorsten
Published: October 2011

The combination of steel and glass used as a hybrid structural element such as a mullion or transom generates a higher level of transparency in facades. In spite of its positive attributes, the brittleness and the lack of plastic deformation of glass increase the risk of a spontaneous failure and the entire loss of load-bearing capacity after breakage of each glass panes independently of the glass type.

However, this typically results in over-design with high safety factors if laminated glass beams are used. The combination of glass beams with the ductile material steel provides an optimised load- bearing capacity with increased robustness. In a modified four-point bending test the load-bearing behaviour of various cross sections of hybrid beams was examined. The test results demonstrated a considerably improved structural and post-breakage behaviour of the hybrid beams compared to conventional glass beams.
Shear Resistant Mechanism of Reinforced Concrete Beams for Seismic Design of Railway Structures
Authors: Watanabe Ken , Yonehana Moe , Niwa Junichiro , Tanimura Yukihiro , Tadokoro Toshiya
Published: October 2011

Reinforced concrete (RC) deep beams are used as a structural member having a shear span to effective depth ratio of not exceeding 1.0 as well as for the application to frame structures, caisson foundations, and corbels. There is, however, a peculiar problem in the analysis of RC deep beams; the variety of supporting condition for RC deep beams induces various failure modes. The goal of this research is to identify the shear-resistant mechanism as well as the shear-load capacity of RC deep beams. To tackle with this objective, the research has focused on internal strain distributions of the RC deep beams under external loading. Based on experimental results, this paper concluded the failure mode and the load capacity of RC deep beams associated with supports condition and the specimen design.
Nanocomposite, an innovative route to large structure and infrastructure protection. A case of study: CNT-doped polyurea.
Authors: Saeli Manfredi , Waisman Haim , Betti Raimondo
Published: October 2011

In this work we focus on experimental studies of polymer-nanocomposites intended for passive protection of civil structures. The material consists of a polyurea-matrix enhanced by different quantities of multiwalled carbon nanotubes. Several tensile and cyclic tests are performed to evaluate and characterize the mechanical behaviour of this new material. Furthermore, we subject the material to accelerated thermal aging and study its performance deterioration which is fairly unknown. The results on the unaged specimens are intuitive and indicate that an arbitrary amount of CNTs may result in suboptimal performance. More specifically, 1% in weight of CNTs yields the best mechanical performance. However, after a long aging term, our findings are interesting and counterintuitive as these nanocomposites become more brittle and break quickly while the virgin polyurea gives the best performance.
Second Bay of Cadiz Bridge. Quality Control and Monitoring
Authors: Martin Marcos , Cayetano Julio , Escamilla Manuel , Sacaluga Marta , Vega Veronica , Perez Javier
Published: October 2011

The new Viaduct over the Bay of Cadiz is going to be one of the most outstanding infrastructures ever built in Spain, due not only to its large dimensions and structural design, but also to the unique environment that surrounds the area where the construction works are taking place. For this reason, the owner (the Spanish Department of Public Works) together with the Contractor and the Technical Assistance Consulting, are developing during the construction a very specific and high tech quality control assessment.