bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural System Identification of Shear Stiffnesses in Beams by Observability Techniques
Authors: Lozano-Galant Jose A. , Emadi Seyyed Behrad , Ramos Gonzalo , Turmo José
Published: February 2021

Despite its importance in some structures, shear deformation is systematically neglected by most static structural system identification methods. To fill this gap, this paper analyzes, for the first time in the literature, the effect of the shear deformation in the inverse analysis of structures. This study is focused on a parametric structural system identification method: the observability technique and it is applied on beams. As the majority of the methods, this technique is based on the Euler-Bernoulli beam theory. The method presented in the literature is unable to identify correctly the characteristics of a structure (such as flexural stiffness) when shear deformation is not negligible. In fact, in this method, the effects of shear deformation are close to those produced by measurement errors. To solve this problem, the observability procedure is updated according to the Timoshenko’s beam theory. This formulation uses an algebraic approach combining both a symbolical and a numerical application. Thus, the updated observability formulation is able to obtain not only flexural stiffness but also shear stiffness. Besides this, for the first time in the literature, a parametric equation of the estimates is obtained. Some examples are presented to illustrate the validity of the new formulation.
An Adaptive NDT Inspection Strategy to Assess the Spatial Variability of Concrete Structures
Authors: Oumouni Mestapha , Schoefs Franck
Published: February 2021

Spatial variability is an essential key in modeling material properties, loading or the deterioration process in structural engineering degradation. Non-destructive Testing (NDT) technique is a crucial tool to characterize this spatial variability. In this paper, we propose an original approach that enables to characterize the spatial variability of structure through discrete and limited measurements in efficient and accurate way. An adaptive approach based on two indicators errors is performed to model the quantities of interest. Firstly, an error indicator is run to estimate an accurate parameter of fluctuations using Maximum Likelihood Estimate (MLE) from a set of measurements. Secondly, the accuracy of the estimated moments of the field from the current number of measures is revised by analyzing the behavior of the second indicator. The advantage of this approach is that the spatial correlation is not neglected between measurements and the range of the correlation is given in good way within a desirable threshold. The potential of the presented approach is demonstrated through numerical examples with synthetic and experimental data.
Uncertainty Assessment and Decision from Concrete Electrical Resistivity Measurements on a Coastal Large Bridge
Authors: Bourreau Lucas , Bouteiller Véronique , Schoefs Franck , Gaillet Laurent , Thauvin Benoît , Schneider Julien , Naar Samuel
Published: February 2021

For RC structures exposed to marine environments, chloride-induced corrosion leads to deteriorations that can be associated to different exposure conditions: tidal, splash and atmospheric. The on-site assessment of the corrosion condition of the reinforcement in concrete relies on a corrosion diagnosis which consists in different techniques and among them non destructive techniques such as half-cell potential, resistivity and corrosion measurements. Although the two first techniques are commonly used, variability and uncertainties in NDT condition assessment remain factors that need to be better understood in order to increase the reliability of the diagnosis particularly in the case of marine structures (in comparison with atmospheric structures for which literature is more important).

The objectives of the Project DéCoF-Ré (2014-2017) were to study both the concrete durability and the corrosion state of the piers of the Ile de Ré bridge which is located in the French Atlantic coast. Concerning the corrosion study, visual inspections, rebar localization, half-cell potential mapping, electrical concrete resistivity mapping and corrosion rate measurements were performed during three years in order to analyse the influence of the measurement procedures, the investigated zones (pier number, side, height) and the environments (tide level, climatic conditions). This paper focuses on the resistivity measurements
conducted with a four electrodes arrangement probe (Wenner type) on the piers of the Ile de Ré bridge
using a vessel. Although resistivity values cannot directly provide an information on the passive/active state
of the rebar because the measurement qualifies the electrical resistivity of the concrete cover (and not the
resistivity of the steel/concrete interface which is usually obtained by Linear Polarisation Resistance
measurements), it is a useful non destructive technique to point out the areas where the corrosion might
be strongest. The purpose of this paper is to outline the errors made while measuring the resistivity given
the uncertainty assessment based on both (i) the repeatability tests and (ii) the material local anisotropy
and measurement's variability. Moreover, a model based on the evaluation of Probability of Wrong
Assessment is proposed to help the owner of the bridge in taking a decision.
Improving the Reliability of On-site Concrete Strength Estimation with Non-destructive Techniques
Authors: Breysse Denys , Balayssac Jean-Paul , Romão Xavier , Alwash Maitham
Published: February 2021

The non-destructive assessment of concrete strength in existing structures is a complex issue. While many standards exist addressing the way non-destructive measurements must be carried out, few exist for the strength assessment itself. Many questions remain unanswered, like for instance the reliability of the strength estimation, the possibility of estimating the concrete variability, or the advantages of combining several non-destructive techniques. These problems have been tackled by a recent RILEM committee (TC ISC 249) whose Guidelines and Recommendations are to be released soon. This paper details their main innovations and how they are expected to improve the engineering practice and the reliability of strength estimation in existing structures.
A multilevel Approach for the Structural Vulnerability Assessment of Historical Water Tunnels. The Case of the Apulian Aqueduct.
Authors: Palmisano Fabrizio , Perilli Pasquale , Venditti Luciano , Casamassima Gianluca , Ventafridda Gerardo
Published: February 2021

The Apulian Aqueduct (South of Italy) is one of the largest in Europe. The so-called ‘Principal Canal’ is its ‘backbone’. Its construction started in 1906 and was completed before the Second World War. Its tunnels in Campania and Basilicata Regions, since the construction, have experienced huge damages. This is why the necessity of a vulnerability assessment according to the present knowledge arises in order to better choose the ‘optimum’ intervention that should also take account of the geometrical and functional peculiarities of these tunnels. In this scenario, taking as an example the case study of the ‘Santa Maria dei Santi’ tunnel of the Principal Canal, the aim of this article is to illustrate the preliminary results of the multilevel approach that the Apulian Aqueduct Society has just started to follow in order to assess the structural vulnerability of this kind of constructions.
A Numerical Study on Prediction of Collapse Pressure of UOE Pipes
Authors: Yi Jiwoon , Kang Soo-Chang , Choo Jinkyo F. , Kim Do Been , Park Wonsuk , Koh Hyun-Moo
Published: February 2021

UOE pipe is widely used for thick-walled offshore pipes thanks to its productivity. UOE pipe is obtained through successive plastic forming stages which exert changes in the material strain- stress behaviour due to hardening and Bauschinger effects. Ovality and residual stress of complex aspect are also induced by the repetition of plastic forming and elastic spring back. These factors make it difficult to predict the collapse pressure of the pipe at the design stage. However the accurate prediction of the collapse pressure is essential for cost and time efficiency considering that sometimes the total length of the pipeline runs over several thousands of kilometers. In this study, finite element analysis is conducted to track the material properties all along the forming process and the collapse pressure is assessed using data mapping technique. Finally, the influence of the extent of pipe expansion on collapse pressure of the UOE pipe is examined.
Seismic Upgrade of a Reinforced Concrete Building using Friction- Pendulum Isolators
Authors: Giarlelis Christos , Koufalis Dimitrios , Antoniadis Panagiotis , Repapis Costis
Published: February 2021

The seismic upgrade of an existing 5-storey reinforced concrete (RC) building through the use of friction-pendulum system (FPS) bearings is presented. The selected building is a model structure, representative of the buildings designed in the period 1960-1980 in Greece. The seismic assessment following the EC8-3 code provisions indicates the structural incapacity of the frame elements. For the seismic upgrade of the structure, FPS bearings are placed above the foundation level. A series of linear and non-linear analyses are performed and the results show that minimal interventions are required only at the ground floor level. The overall seismic performance and the limitations in the applicability of the proposed solution are discussed. It is concluded that seismic retrofitting through seismic isolation of existing buildings is a very good approach and should be widely used.
Structural Health Monitoring of Existing Bridges using Bridge Weigh- in-motion Measurements – Value of Information Analysis
Authors: Skokandić Dominik , Mandić Ivanković Ana , Žnidarič Aleš
Published: February 2021

Implementation of Value of Information (VoI) analysis regarding Structural Health Monitoring (SHM) data and corresponding assessment results of Case Study bridge is presented in this paper. SHM data (traffic and structural), obtained with bridge weigh-in-motion (WIM) measurements, are im- plemented in the probabilistic assessment of load carrying capacity of a Case Study Bridge.

In the first part of the paper, a short overview of SHM measurements and description of Case Study Bridge is presented, along with the assessment results. Link between SHM data and the correspond- ing structural performance is defined, and it is shown that application of WIM measurements in the assessment of existing road bridges can increase their reliability level and, therefore, extend the predicted service life of these bridges.

In the second part of the paper, implementation of VoI analysis on Case Study Bridge is discussed and all the factors of interest are presented in the VoI flowchart. Furthermore, decision tree for VoI analysis is defined, along with correspondent outcomes, actions and resulting system states.

Further steps and recommendations are discussed in the final part of the paper, including correla- tion factors, possible outcomes and, finally, discussion of resulting indicator as a benefit/cost ratio of Bridge WIM measurement implementation in assessment of existing bridges.
Optimizing Monitoring – Implementation of Draft Guideline and Case Study of Roof Exposed to Snow Loads
Authors: Diamantidis Dimitris , Sýkora Miroslav
Published: February 2021

This contribution addresses the optimisation of monitoring and decision-making criteria regarding the future use of structures and the related implementation in modern guidelines. A summary of the state-of-practice reveals deficiencies that are addressed by prospective guidance for the anticipated updates of standards, providing a general methodology to obtain cost-optimal decisions using limit state design, probabilistic reliability analysis and cost estimates. The implementation of a draft guideline and the corresponding risk-based approach are illustrated in a full-scale case study dealing with the roof of a stadium located in Northern Italy. The results demonstrate the potential of using monitoring systems and probabilistic reliability analysis in order to support decisions regarding safety measures such as snow removal, or temporary closure of the stadium.
Bridge quality control using Bayesian net
Authors: Isailović Dušan , Hajdin Rade , Campos e Matos José
Published: February 2021

Bridge quality, as a measure of its compliance with the performance goals is tracked by the quality control plan. In other words, the quality could be understood as a comparison between performance indicators and performance goals. Reliability is widely recognized as the most important key performance indicator. This paper proposes a new approach to the mentioned comparison that provides valuable information and consequently improve decision-making regarding future course of action.

A current quality control plan is facing certain limitations. Defects are being detected in the inspection and documented in the inspection report. In the most cases, however the essential information for reliability assessment i.e. the extent and location of the defects is not recorded.

The proposed approach uses a Bayesian net for the prior analysis of the bridge. Afterwards, the net is updated after each inspection, allowing a posterior analysis of the bridge reliability. A damage free state of the bridge, so-called “virgin state” is adopted as a baseline, while inspectors are asked to estimate the severity of the defect and consider the vulnerability of the structural system for the locations of defects.
Ultra High-rise Building with High Seismic Performance using High Efficiency Hybrid Vibration Control System: [Tokyo Garden Terrace Kioicho] Kioi Tower
Authors: Koitabashi Yuichi , Kimura Seiya
Published: February 2021

This paper describes that Hybrid Seismic Control System is applied in Tall Building “Kioi-tower” we had designed in Tokyo, Japan.

Outline of “Kioi-tower” is as followed, 33stories plus 2 penthouses, 5 ground floors. 177.65m high. Total Floor Area: 227,200m2, Typical Floor Height: 4.45m or 3.40m. It provides office, hotel and retail. This building has Hybrid Seismic Control System means both viscous dampers and buckling restrained braces (BRBs) are used in the mega structure.

Point of the System is below,

Deformation and velocity of BRBs and viscous damping braces are amplified by the Mega structure composed with transferring girder and steel plate column.

The efficiency of energy dissipation is enhanced and shear force is reduced to 75%.

Maximum axial force is reduced to 75% compared with the absolute sum of the axial force of BRBs and viscous damper because of phase differences.

Dampers of this system absorb about 15% more energy compared with only steel damper or viscous damper.

Structural monitoring system is also installed in this building. This system helps to elongate the life span of the building, and efficiently maintain seismic control devices and earthquake resistance elements easily.
5/6 Arches: a Megastructure becoming a land marking Monument
Authors: Geyer Silvia , Pin Claudio , Lombardini Daniela
Published: February 2021

5/6 Arches is an iconic project serving as gateway to Doha’s West Bay Business District. The two arches are made of 10.000 tons of steel, with a structural cable net that comprises 90 tons of Full Locked Coil (FLC) cables and their sockets. Designed by AECOM and realized by HYUNDAI CONSTRUCTION and EVERSENDAI, it represents the heaviest steel monument in the world. Redaelli’s contribution to this land marking structure includes cables and clamps supply, engineering of cable net installation and tensioning and all related site activities. The net is composed by diagonal and valley cables, connected by 473 crossing clamps for a total mass of 80 tons. Clamps are specially designed with a modular scheme to accommodate for several angles at cable intersections.
Elastic torsional rigidity of multi-cell box girders with corrugated steel webs
Authors: He Jun , Li Chuanxi , Tan Chao , Dai Xiaodong , Wang Sihao , Liu Yuqing
Published: February 2021

This paper focuses on the investigation of torsional behaviour of wide and multi-cell box girders with corrugated steel webs by means of theoretical and numerical analyses. Based on the pure torsion theory of thin-walled structures, the theoretical formula for calculating the elastic torsional rigidity of multi-cell box girders with corrugated steel webs was derived. Then, a parametric analysis was carried out using the elastic finite element analysis method to investigate the effect of the corrugation profile, thickness of corrugated web and concrete slabs, the height and width of composite girder on the torsional rigidity of multi-cell box girders with corrugated steel webs. It is found that the torsional rigidity of multi-cell box girders with corrugated steel webs can be greatly improved by proper increase of web thickness and girder height. Finally, a revised formula for calculating the torsional rigidity was proposed, which can provide a reference for the design of torsional behaviour on multi-cell box girders with corrugated steel webs.
Welds for High-Strength Steels – Development of New Design Rules
Authors: Stroetmann Richard , Kästner Thoralf , Werner Lars
Published: February 2021

Due to the resource-conserving use of material, the application of high-strength steels provides economic and ecological advantages in many types of constructions. However, for welded con- structions, some of these advantages are partially offset by conservative design rules and more complicated execution regulations. The objective of the ongoing AiF-FOSTA research project P1020 is the development of principles, which lead to significant improvements of design and execution rules for welded connections of high-strength steel structures. The development of design rules aimed at a simpler more economical execution. This paper gives an overview of the research pro- ject P1020 including the new design model. It describes the development of the flat tensile test method for the assessment of the mechanical properties of welds and several experimental para- metric studies.
Shear Tests on RC Beams without Stirrups under Uniformly Distributed Load
Authors: Beck Alexander , Kaufmann Walter , Konradi Daniel
Published: February 2021

Despite hundreds of theoretical and experimental investigations carried out over the past decades, still no generally accepted, mechanically based model for the shear behaviour of structural concrete members without transverse reinforcement exists. The available theoretical models rely on limited experimental substantiation since the vast majority of the tests to date have been conducted on small, simply supported beams under point loads, which do not appropriately reflect real structures. Nevertheless, code provisions for shear design in structural concrete based on these theoretical models are used for the design of large structures under complex loading conditions. A comparison of experimental results with theoretical models concerning the shear strength of RC members without transverse reinforcement indeed reveals discrepancies between experimental and theoretical failure loads, and a lack of experimental data particularly for large specimens under distributed load. Therefore, two large-scale shear tests on simply supported, uniformly loaded beams without stirrups have been conducted to extend the experimental basis. This paper presents the results of these two experiments and compares them with various theoretical models and code provisions for shear in structural concrete. The failure loads evaluated with the theoretical models are in good accordance with the experimental results

– they are within a range of 20 % – but at the same time not conservative. The shear strengths determined from code provisions showed a rather big scatter and partially exceeded the experimental failure loads as well.
A Decision Model for the Investment in Technology to Reduce Concrete Rework
Authors: Podges Tian Martin , Wium Jan Andries
Published: February 2021

Developments in technology allow for improved processes in construction. Often, project teams face the option of acquiring new technologies, but it is not clear if the expenses merit the benefits. This paper presents a method to choose technology that can reduce rework in structural concrete caused by poor construction quality. The technologies considered are identified as those that can be used to improve quality monitoring during construction. The scope of the investigation was limited to structural elements, such as beams, columns, slabs and concrete walls. The research questions for this study were as follows: (i) what are the causes that lead to poor construction quality of structural concrete; (ii) how can technology be used to improve the construction quality and how effective would it be and (iii) can a decision model be developed to assist a contractor to invest in such technology. A decision model was developed, based on risk and cost, to assist the user in the investment decision of acquiring technology to reduce rework. The approach applies to mega project and smaller projects alike, all to the benefit if improved processes.
TMD Systems for Increase of Damping within High-Rise Buildings
Authors: Huber Peter , Paroli Luca
Published: February 2021

High-rise buildings with long structural periods of 4-5 s and greater suffer due to wind and earthquakes mainly from rather big lateral displacements on top of up to 2m and more. These displacements result in loss of comfort for persons inside and may induce low cycle fatigue due to large, long lasting vibrations after a storm event or earthquake. To overcome these problems damping must be added to the structure.

A technically feasible and also economic approach to increase structural comfort and to reduce the vibration decay times after extreme winds or earthquakes is the application of Tuned Mass Damper systems.

The aim of this paper is to introduce and describe the basic requirements for TMDs and design of two large TMD systems for high-rise structures with their function benefits and damping increase:

SOCAR Tower in Baku/Azerbaijan is 200 m tall and has a 450 t mass double pendulum type TMD with passive damping, and

Danube City (DC) Tower in Vienna/Austria is 220 m tall and has a 300 t mass single pendulum type with semi-active damping, which is adopting in real time its damping capability. The system includes a full monitoring of accelerations, frequencies, displacements and viscous damper forces.

Both TMD systems have in addition redundant end stopper devices to avoid uncontrolled seismic displacements of the huge TMD mass block.

The efficiency of the TMD systems was proven by calculation and measurements on site for both projects that accelerations were significantly reduced to provide the necessary comfort and decay times of vibrations due to extreme impacts were limited to a few minutes.
Occitanie Tower, a City in the Tower: For an Interactive Structural Design with the Architecture and Multifunctionality of the Tower
Authors: Jaradeh Youssef
Published: February 2021

The development of cities, the growing concern for the environment and advancement in urban planning are revolutionizing the construction of buildings in France.

Increasingly we see the terms; mixed-use, participatory gardens, standards: HQE, BREAM and “green” that take their place alongside the traditional considerations of building design, which was already challenging engineers to design higher, more beautiful and more comfortable.

Since the “Réinventer Paris” projects, Compagnie de Phalsbourg have understood this new transformation have taken an important role to develop bold, aesthetic projects that are sympathetic to nature and their urban context.

Arcadis was selected by the Compagnie de Phalsbourg in 2016 to support this adventure in the field of structural and functional design. The project which is the subject of this article is Tour Occitanie, located in the city of Toulouse between Matabiau railway station and Georges Pompidou bridge. It responds to the competition launched by the City of Toulouse, represented by Europolia.
Simplified Procedure for Estimating Modified Response Modification Factor of a Complex High-Rise Building
Authors: Munir Ahmed , Kanwal Farheen
Published: February 2021

Response modification factors (R-Factor) are used to modify the elastic seismic response obtained from the linear elastic analysis to account for the effect of allowed damage. Recent studies show that UBC-97 code-based response modification factors are not valid for high-rise buildings. Where wind governs the design, their validity comes in question further. In this study, an actual 40- storied tall RC building located in Bangkok, Thailand is investigated in detail to determine the actual R-factor in each and every significant mode located in low to moderate seismic risk area with mean hourly wind gust of 90 MPH and exposure type-B. The code based designed building is analyzed using elastic displacement-based pushover analysis procedure in each and every mode to determine the modified R- factor. It is found that actual R-factor is in the order of only 1 to 1.25 in all significant modes.
The Mega Floating City Green Float—Part I: Concept and Technological Innovations
Authors: Takeuchi Masaki , Ono Shuhei , Hasebe Masanobu
Published: February 2021

The world is currently facing a population explosion and numerous problems related to aspects such as energy, water, food, CO2, and natural resources. Fortunately, however, oceans cover 70% of the Earth’s surface and have tremendous potential and a major influence on the global environment and human sustainability. The mega floating city “Green Float” is a new conceptual model for an environmentally friendly island city and is under development by Shimizu Corporation, Japan. The Green Float concept embodies two areas of innovation, namely, “green” innovation and “float” innovation. Locating Green Float at a low latitude near the Equator minimizes the float risk represented mainly by wave heights and strong winds and maximizes the green potential such as renewable energy.
A Review of Structural Robustness with Focus on Timber Buildings
Authors: Huber Johannes A. J. , Ekevad Mats , Girhammar Ulf Arne , Berg Sven
Published: February 2021

With an increasing number of storeys, timber buildings require closer attention to structural robustness. If a building can survive unforeseen events (e.g. accidents, terrorism), lives can be saved. The literature appears to be rather limited concerning robustness of timber buildings. This paper aims to give a brief review on robustness in general and design guidelines for timber in specific. The results indicate that connection design is a key aspect for robustness. Like in seismic design, by using the ductile capacity of connectors, the brittleness of timber can be controlled. For light timber-frame buildings, more guidelines exist than for posts and beams and cross-laminated timber, which both seem to be similar to steel frames and precast concrete respectively regarding robustness.
Seismic Design and Off-Site Construction of College Buildings for 500 Students with Timber Frame 3D Modules in Clisson (near Nantes, France)
Authors: Thépaut Rémi , Sébille Patrice
Published: February 2021

Clisson public college of 5 767 m2 consists of a two storey building, a restaurant, as well as four staff dwellings. The classrooms are grouped on two floors organised around two patios. Designed to accommodate about 500 students, the college is designed in functional and modular blocks and might be easily extended if necessary.

Building work lasted 12 months including prefabrication work. Ninety eight timber modules, up to 16 meters long, were prefabricated and pre-equiped in a workshop located less than 2kms away from the construction site. This off-site building technique takes a very specific, challenging and controlled industrial process. Similar in appearance, each module actually has its own specificities (size, openings, equipments, finishing...).

Modules are designed to earthquake construction detailing and structural calculations were carried out according to Eurocode 8: seismic joints; load paths, connections and anchors resistance; ballast foundations. 3D spectral modal analysis resulted in long and complex iterative calculations due to timber frame walls stiffness settings. Nevertheless structural optimisation was achieved.

The paper intends to present different aspects of the design and construction of this off-site building process with a strong focus on structural design of multi-material frames (concrete, steel, timber) of the main entrance hall.
The Submerged Floating Tube Bridge as an alternative for a crossing: pros and cons
Authors: Eidem Mathias , Minoretti Arianna , Xiang Xu , Aasland Tale
Published: February 2021

The paper describes the pros and cons of the Submerged Floating Tube Bridge (SFTB) as an alternative solution for different types of crossing, having their own characteristics in terms of depth, width, geotechnical properties of the seabed, exposure of the area to the different types of loads and so on.

The analysis is based on several feasibility studies performed by the Norwegian Public Roads Administration (NPRA) in the last years for the E39 project, where different solutions of SFTBs have been compared to floating bridges and suspension bridges on tension leg platforms. An additional evaluation of the SFTB compared to more traditional bridges is described here.

Different technical solutions for the SFTB can overcome local specific challenges of the crossing; for this reason it is important to know the advantages and disadvantages of the different SFTBs structures, in order to choose the best one for each specific site. A comparison between the SFTB and the other type of bridges will help to understand when this type of structure can be competitive and when it will not be.
Wind Engineering Challenges of Modern Footbridges
Authors: Bagnara Anna , Cammelli Stefano , Berbekar Eva
Published: February 2021

The on-going development of footbridge design embraces a wide range of forms and organic architectural styles. Curved decks as well as complex pylon and stay-cable arrangements inevitably impose severe limitations on the application and interpretation of results of conventional section model wind tunnel testing. Also, differently from long-span road bridges, footbridges are typically located in an urban setting and are generally subjected to high levels of atmospheric turbulence. These two factors emphasize the importance of including ad hoc wind tunnel testing at an early stage of the design process. Making use of a number of case studies, the authors of this technical paper will share their extensive experience in developing and implementing wind engineering strategies capable of enabling the vision of modern footbridge designers.
Aerodynamic and Aeroelastic Design of Long Span Bridges: Recommendations for Chile
Authors: Caram Matias , Valenzuela Matías A.
Published: February 2021

Bridge design under wind load in Chile has been limited to the regulations established in the road manual (Manual de Carreteras in Spanish) and the specifications for traditional bridges presented in the AASHTO Standard code and the LRFD (Load and Resistance Factor Design). All in which is assumed static conditions and fundamentally developed for construction stages.

Nevertheless, those codes are not applicable to medium to long span bridges due to the aerodynamic and aeroelastic behaviour they might present. Nowadays, bridge design in Chile has included new typologies of bridges such as the Chacao multi-span suspension bridge, therefore this requires a review and analysis of the current design codes, especially when aerodynamic and aeroelastic affects the superstructure as well as the infrastructure.

The following paper presents a proposal of recommendations for long span bridges in Chile, considering the international experience gathered and the national development of Chacao bridge.
Investigation of Long-Span Bridge Stability in Wind Tunnel
Authors: Solovev Sergei , Sokolov Viktor , Novikov Artem
Published: February 2021

Main types of aero-elastic instability for bridges with spans over 100 meters are considered. Methods for investigation of bridge oscillations in a special-purpose experimental facility - the Landscape Wind Tunnel - are described. Examples of tests with elastic similar models of bridges are given, and measurements to mitigate dangerous oscillations early in the bridge design process are described.
Nonlinear Flutter Collapse Analysis of the Tacoma Narrows Bridge with a New Nonlinear Aerodynamic Force Model
Authors: Zhou Rui , Yang Yongxin , Ge Yaojun
Published: February 2021

Historically, the collapse of the original Tacoma Narrows Bridge on 7 November 1940 at the wind velocity near 19m/s (U=19m/s), shed light on the importance of assessing aerodynamic performance in long-span bridge design, especially for the nonlinear flutter instability. In order to accurately reproduce the flutter collapse phenomenon of the Tacoma Narrows Bridge, and explore the role of hangers in the large-amplitude oscillation process, a new nonlinear aerodynamic force model based on nonlinear differential equations in time domain was firstly proposed to simulate the aerodynamic force. A set of parameters in the nonlinear model for the H-shaped deck were then fitted and validated. Accordingly, Based on the self-developed C# language program, the combination of a nonlinear finite element model of the three-dimensional suspension bridge and the nonlinear aerodynamic force model were used to calculate the structural responses and failure modes of the bridge under the uniform flow and turbulence flow, respectively. The comparison of time histories, hysteresis curves and amplitude spectrums between the calculated and fitted results of the aerodynamic force show that the nonlinear aerodynamic force model could simultaneously consider the nonlinear effect and unsteady effect of the aerodynamic force. The maximum torsional displacement responses and hanger’s stress at the 1/4L of deck are the 41.4° and 1492.3MPa under the uniform flow of U=21 m/s, respectively. Meanwhile, the maximum torsional angle and the maximum stress of the hangers are 41.6° and 1513.3MPa under the turbulence flow of U=19 m/s, respectively. Therefore, the fracture failure of hangers at the 1/4L of the deck further accelerates the anti-symmetric torsional flutter collapse of the bridge.
Seismic Isolator, Damper and Expansion Joint System for two Viaducts of Toluca – Mexico City Intercity Train
Authors: Paroli Luca , Huber Peter
Published: February 2021

The Toluca–Mexico City Intercity Train will connect the metropolitan areas of Toluca with Mexico City. The seismic condition of max. 0,77 g for 1 s structural period represents a major challenge for two of the longer viaducts - namely Viaduct 2 and Viaduct 4 - with a total length of 3,8 km and 1,4 km respectively. Strengthening design of the structural members was technically not possible anymore even knowing that it also would not be economical. The applied longitudinal seismic isolation, lateral guiding and damping system according to EN1998 and EN15129 will significantly reduce the longitudinal forces by approx. factor three to five in combination with reasonable displacements of the decks. The final goal of lesser total structural cost as well as ensuring the safety of the structures and its functionality after seismic events was achieved.
Near-fault Isolation of Cable-stayed Bridge in Longitudinal Direction using Linear Friction Damper
Authors: Guo Junjun , Yuan Wancheng
Published: February 2021

In the current research, an innovative linear friction damper is proposed to control the seismic responses of cable-stayed bridges in longitudinal direction under near-fault ground motions. The working mechanism and force-displacement relationship of this new device are introduced in detail. The numerical model of the bridge is established by OpenSees platform. 12 earthquake records with velocity pulses selected from PEER website are adopted as input ground motions. The seismic responses of the bridge with and without this dampers are obtained after conducting a series of nonlinear time histories analysis. The numerical results reveal that this new type friction damper can effectively limit the relative displacement between the superstructure and substructure of the bridge in longitudinal direction to a reasonable range. Thus, pounding between deck and abutment can be mitigated.
Experimental Investigation on Transverse Steel Damper Seismic System for Cable-stayed Bridges
Authors: Zhou Lianxu , Ye Aijun , Wang Xiaowei
Published: February 2021

To investigate the seismic performance of transverse steel damper seismic system (TSDSS), a shake table test is conducted on a 1/35-scale model of Sutong Bridge, a long span cable-stayed bridge with a main span of 1088 m. During the test, two types of transverse structural systems are considered, one is the TSDSS, an energy dissipation system with the transverse steel dampers (TSDs) placed at deck-tower/bent connections, and the other is a fixed system with transversally fixed bearings. Two ground motions for different site types (i.e., hard and soft) are selected as inputs. Results show that

(1) the TSDSS significantly reduces lateral horizontal forces at the deck-tower/bent connections, and reduces displacement and curvature demands along tower and bent shafts, meanwhile limiting the deck-bent and -tower relative displacements at an acceptable level for practice. (2) the isolation efficiency of TSDSS are robust regardless under soft- or hard-site ground motions; for both waves, the percentages of the reduction of curvature demands at bottoms of the bent and tower are averagely around 36%.
Characterization of Dissipative Behaviour of a Reinforced Concrete Mock-up after Soft Impact Tests through Wavelet Analysis
Authors: Vacca Nicolas , Rouzaud Christophe , Hervé-Secourgeon Guillaume , Galan Mathieu , Argoul Pierre , Rospars Claude
Published: February 2021

The objectives of this communication is to characterize the soft impact response behaviour of a reinforced concrete mock-up (OECD/NEA IRIS Phase 3 mock-up, part of a benchmark), and to evaluate the ability of some mechanical models to represent the energy dissipation during and after the impact. Results from the benchmark show insufficient dissipation in numerical models.

Using time-frequency analysis, the dissipative behaviour of the mock-up under impact is evaluated. The stiffness and dissipation associated with the first mode are shown to be amplitude-dependent. This non-linear effect seems to be of a different nature than damage or plastic deformation. A simple rheological model with friction exhibits a similar behaviour.
BRB and Viscous Damper Hybrid Vibration Mitigation Structural System: Seismic Performance Analysis Method and Case Studies
Authors: Zhao Xin , Li Hao
Published: February 2021

This paper proposes the seismic performance analysis method for buckling-restrained brace (BRB) and viscous damper (VD) hybrid vibration mitigation structural system. The dynamic equilibrium equation is introduced firstly. BRB is simulated by bilinear kinematic hardening model and nonlinear VD is used. Their one-dimensional constitutive relations are illustrated, based on which their two-dimensional constitutive relations are derived. The Newton-Raphson iteration is constructed. And it’s combined with Newmark-β step-by-step integration methods, based on which the formulas for calculating the equivalent damping matrix of BRB and equivalent stiffness matrix of VD are derived. Finally, the proposed seismic performance analysis method is validated using 2-story plane frames. And a real super tall building structure is employed to verify the applicability and effectiveness of BRB and VD hybrid vibration mitigation structural system.
Optimized Design of Seismic Isolation Systems for Existing Bridges
Authors: Furinghetti Marco , Peloso Simone , Lanese Igor , Lenzo Simone , Pavese Alberto
Published: February 2021

Nowadays base isolation represents one of the most effective solutions for seismic protection of both building and bridge structures. Thanks to the provided low stiffness and the high dissipation capacity, a significant reduction of internal forces induced in the superstructure can be obtained, with limited increased displacement demands. However, for bridge structures, the definition of the layout for anti-seismic devices can strongly affect the overall response of the system, due to the interaction between properties of each isolator and stiffness characteristics of piers. Precisely, the topography of the bridge site may lead to relatively high vertical supporting elements. Such elements would not take advantage of an additional isolation layer: thus, the displacement seismic demand of the deck can be directly accommodated through the flexural deformation of tall elements. On the other hand, isolators on short piers are generally needed, in order to avoid unexpected brittle shear failures.

In the present endeavour a simplified optimization procedure is proposed for the most efficient definition of the seismic isolation system for existing bridges retrofit. The response of a case study structure has been assessed for the calibration of the implemented parameters, through Non- Linear Time History Analyses, by applying spectrum-compatible natural records. Finally, a framework for hybrid simulations with sub-structuring has been considered, aiming at evaluating the effectiveness of the presented design strategy, by means of an experimental validation.
The design of two Large Span Arch Bridges in the Port of Rotterdam
Authors: Steenbrink Arjen , van der Burg Mark
Published: February 2021

The existing movable Caland Bridge in the Port of Rotterdam is a part of the ‘Havenspoorlijn’ (Port Railway Line). Because of the high intensity of both the shipping and railway traffic the existing bridge has a lack of capacity. Therefore the port of Rotterdam designed a new railway track to bypass this crossing. In this new route (Theemswegtracé) two new arch bridges and a 4km long concrete simply supported beam structure will be realized. This paper will be about the design of the two arch bridges, one with a single span of 172,8m and the other with a continuous beam over 4 supports with a total length of 269,1m.
Managing data workflow from concept to commission – BIM for bridges
Authors: Chanard Jean-Pierre
Published: February 2021

BIM in bridges is a new challenge. Managing data from concept to Commission can only be done if we well understand the different phases of a project, each of them needing its own special data, its own required accuracy and specific geometry, leading to different models and often to different type of data. Transmitting common data from phase to phase must be done with a minimum loss. On the other side, it is useless to transmit data that will not be used by following phases, and an intelligent selection must be done.
Non-conventional Cable System in Multi-span Cable-stayed Bridges
Authors: Cid Clara , Baldomir Aitor , Hernández Santiago
Published: February 2021

The design of multi-span cable-stayed bridges requires the control of horizontal displacements on the towers head when unbalanced loads are applied on deck. There are several strategies to reduce these displacements, being one of them the use of crossing stay cables in a central section of each main span. Based on this bridge typology, a general methodology to obtain the optimum cable system has been developed. Number of cables, anchor position of cables on the deck, cable areas and presstressing forces are considered design variables simultaneously into the optimization process. Each cable anchor position is associated to an independent design variable, allowing overlapping stay cables, different spacing of cables along the deck as well as different number of cables on each side of the same tower. Queensferry Crossing has been chosen as application example where the final design achieves an important saving in cable steel.
Juan José Arenas: a Philosophy of Bridge Design
Authors: Capellán Guillermo , Sacristán Miguel , Guerra Santiago , Merino Emilio , Martínez Javier
Published: February 2021

Juan José Arenas, IABSE’s 2017 International Award of Merit in Structural Engineering, was a really prolific engineer in the design and construction of bridges and signature structures.

This article briefly synthesizes the main projects of Juan José Arenas since he founded Arenas & Asociados. This phase runs from 1999 to his decease in November 2017. The last years of his professional career, but also those of more experience and knowledge. This period leaves a laudable legacy, with worldwide recognized structures as the Third Millennium Bridge in Zaragoza or the Viaduct over River Almonte (HSR Madrid-Extremadura). But, in addition, many other examples that, due to their uniqueness, suitability, soundness or details, deserve their mention and remembrance.
Skew Placement of Arches with respect to the Bridge Deck
Authors: Backer Hans De , Outtier Amelie , Van Staen Gilles , Van Puymbroeck Evy , Ul-Abdin Zain
Published: February 2021

Designers try to find new ways to make landmark bridges slenderer and distinctive. A new trend for arch bridges is placing the arch not co - linear with the bridge axis, but slightly skew. While visually attractive, this concept introduces a number of design problems which are not normal for arch bridges: the arch becomes subjected to significant out of plane bending moments, a permanent torsional effect develops, hangers are not possible in certain areas because of conflict with traffic and the tied arch concept becomes quite difficult to realize. The aim of this research is to study the skew arch concept using finite element modelling. A parametric study is undertaken to investigate the main design problems and to find an allowable application area in terms of bridge span, bridge deck width and skewness of the arch. Hereby, two different skew arch hanger configurations are considered including also a minimization of the number of hangers.
Applying a Set-based Parametric Design Method to Structural Design of Bridges
Authors: Mathern Alexandre , Rempling Rasmus , Tarazona Ramos David , Luis Fernández Santiago
Published: February 2021

Set-based design has been widely applied in manufacturing and product development, as it allows to consider a large number of alternatives during the design process. The design process in civil engineering projects may benefit from this alternative design approach, however its applicability in this field remains unexplored. The purpose of this study is to investigate the potential of applying a set-based parametric design method to the structural design of bridges. The method developed here combines set-based design, parametric design, finite element analysis and multi-criteria decision analysis. The developed method is applied to two existing bridges considering two sustainability criteria in the evaluation of the alternatives: material cost and carbon dioxide (CO2) equivalent emissions. Preliminary results indicate that the method leads to bridges that are more efficient with regard to the selected sustainability criteria.
Large Span V-shaped Pier Continuous Rigid Structure Design of China- Maldives Friendship Bridge
Authors: Haizhu Xiao
Published: February 2021

The China-Maldives Friendship Bridge is a Foreign Aid Project by the Chinese government. The bridge crosses the Gaadhoo Koa Strait, with a total length of 2km. The maximum water depth at bridge site is 46m and long-period waves have a significant impact on the project. The engineering geology is mainly coral reef layer. The main bridge is V-type pier six-span continuous rigid frame bridge ， the span arrangement is (100 +2 × 180 + 140 +100 +60) m, with the total length of 760m. The superstructure of main bridge adopts the hybrid girder composed of concrete beam + steel box girder. The main pier foundation of the main bridge is made of steel pipe composite pile.