The design and performance evaluation of a self-controlled system are investigated. An autonomous set of pendulums with different branches is considered. A mathematical model is derived, and the damping mechanism due to the transfer of energy between the central column and its attached branches is pointed out. The case of earthquake loads has been tested. Dynamics study shows that the energy received by the central column is distributed to the different branches, leading to a self-vibration control of the system. It is also found that one can increase the damping ratio according to the physical characteristics of the structure. This is a good candidate for earthquake protection of mechanical structures.

Discussing the needs of the prevalent structural concept (the reinforced concrete frame with masonry infill: RCF) during the design and building process in order to provide adequate safety under earthquake loading, the robustness of this concept is called into question. It is concluded that, as long as we continue to build in this way, un-manageable earthquake disasters will strike our large urban centres. During the past two decades, new structural concepts have emerged that are not only more robust then RCF but also more economical to build. Among these are reinforced masonry, confined masonry and so-called seismic control concepts like Base Isolation, Hyde System and Tendon System. These concepts, their applications and advantages are briefly presented, also in the context of historical structures. For these, the Tendon System is particularly suitable, but basic understanding of the seismic performance of historic structures is missing. This is particularly true for Nepalese pagodas. It must be investigated using full-scale shaking table tests before any intervention or reconstruction should be allowed. Finally, strategies are suggested how to promote these concepts in order to substitute RCF eventually. If successful, widespread structural failures under earthquakes will become history.

Earthquakes are catastrophes that affect all parts of a society and a country. Consequently, they have to be examined integratively and measures of restoration and precaution have to include not only safer rebuilding and damage minimization but many more fields, such as economy, infrastructure or social structure of the society. Using the example of the Gorkha 2015 earthquake in Nepal, geoscientific, technical, medical, economic, social, political and legislative aspects of such a catastrophe are presented and discussed in detail as well as with respect to the special situation in a developing country. Particularly, the connections and interactions between all these fields are emphasized. In addition, suggestions are presented, in which way preparedness of the society on all levels of technical and medical precaution, administration, politics and not least with respect to culture and social structure can be reached and resilience towards future earthquakes and other catastrophes can be increased.

Distributed hybrid simulation is an approach to large-scale testing in which the system under test is split into several sub-structures which are tested or simulated in different locations. Data are passed between the sub-structures at each timestep so as to ensure that the distributed experiment realistically simulates the full system under test. This approach optimises the use of resources at different locations to achieve a more representative experiment. While different software to conduct distributed simulations exists, there are no standards and specifications to organise and plan the experiments, and as a result the different systems lack inter-operability. To address these issues, we have developed a high-level specification called Celestina, which provides a framework for conducting a distributed experiment. Celestina specifies the services to be implemented, under three main headings of networking, definition and execution, and supports the data exchange during a simulation. It does not force any particular implementation or method of data exchange. This paper summarises the Celestina specification and describes one implementation. Lastly, a validation experiment is presented, involving distributed numerical simulations of an earlier local hybrid experiment, in which Celestina controls the experiment planning and data exchange effectively and with minimal computational overhead. (C) 2014 American Society of Civil Engineers.

Distributed hybrid testing offers a promising approach to use resources from geographically separate laboratories in a highly efficient way, to perform more complex, larger-scale tests than are possible in most individual laboratories. The method involves splitting a structure into a set of substructures (some tested physically, some modelled numerically) located in different laboratories. Simulation of the full structural response involves simultaneous testing of the substructures with feedback of data between them, requiring fast communication through computer networks. To handle systems involving rate dependence, there is a desire for test speed to approach real time. In addition to the increased difficulty of tracing errors caused by the distributed environment, organizing and planning distributed experiments creates much more complexity than in single-laboratory hybrid tests. This points to the importance of a platform to support the testing activities. This platform has been achieved by means of a specification called Celestina, created at the University of Oxford. Celestina provides a framework for conducting the experiment workflow. It provides a specification for the services to be implemented under three main headings of networking, test definition and experiment execution, and supports to data exchange during a test. It does not force any particular implementation, which can be independently developed and implemented under this framework, nor does it restrict the actual method of data exchange. In this article we discuss the design and conception of the specification as well as one implementation that has been validated through a series of substructured “numerical experiments” in partnership with the University of Kassel.

One of the tasks within the FP7-SERIES project was the creation of a European Platform for Geographically Distributed Tests. This platform was envisioned to be able to deal with different protocols and algorithms so that its users and facilities would not be restricted to one specific protocol. The platform should also prove the possibility of performing geographically continuous distributed tests since up to now such tests were stop and go. However, through the use of an efficient substructure algorithm, continuous tests can be performed using standard network connections. With that in mind, several activities were performed at the University of Kassel that involved major earthquake engineering facilities around the world. With each partner, continuous time-scaled hybrid simulation tests with a non-linear substructure were performed exploring the available protocols. In addition, preliminary tests using Large Numerical models and a Linux cluster were also performed in order to assess the extensibility of the platform to more complex and larger models.

Past earthquakes have demonstrated the vulnerability of deck bridges, which are the most common type in elevated roads. Especially over-loading of piers and drop-off of sections are a continuing concern. Seismic Control concepts, when correctly understood and applied, can provide the necessary physical force limits and reduced displacements even under loading beyond the design limit. The concept of choice here is the Hysteretic Device System since deck bridges usually provide a natural seismic link between piers and deck. To study the performance and robustness of this concept, shaking table tests were performed at IZIIS, Skopje during the NATO-SfP project ISUbridge on a model deck bridge using controllable friction devices UHYDE-fbr to simulate the behavior of different passive devices including device failure. The tests showed that a stiff-ductile device in the link not only protects the piers from over-load, but also provides superior performance compared to viscous or soft base-isolation devices. Failure of such a device further reduced the demand on the piers but did not lead to excessive deck displacements or damage, thus confirming considerable seismic robustness for the HDS concept. This corroborates observations on the Bolu viaduct during the Kocaeli event. Unfortunately, HDS is often confused with Base- Isolation, which leads to the application of BI-devices, like LRBs and thus a reduction in performance and robustness. This is even more true for viscous devices, which are favored today.

Although major improvements have been made in the field of hybrid simulation, the numerical models used in the tests are fairly simple, reaching only an order of ten Dynamic Degrees of Freedom (DDOF). However, the presence of large computational facilities along with the implementation of a Platform for Geographically Distributed Seismic Tests (PGDSTs) provides the possibility to use large and complex numerical models, maybe consisting of a couple of thousand DDOF, within the context of continuous hybrid simulations that work with acceptable time scale factors. However, the use of these facilities requires some approach from both parts in order to solve major issues such as the operating mode and thread to transfer data between facilities, or adapting the substructure algorithms to work in a parallel fashion through the use of special libraries and specifications among others. This paper presents ongoing work within SERIES to assess the extensibility of the PGDSTs to use HPC facilities as well as adapting the substructure algorithm developed by Dorka, which has been used successfully not only in Earthquake Engineering but also in aerospace applications.

Today, mature beam-column joints exist for steel-concrete composite structures and their structural behaviour has been studied in many tests. Finite Elements can be used to study such regions in detail but are impractical for the analysis of a complete frame. This paper presents a scaling method that allows for the transfer of local behaviour to a higher scale analysis and back using orthogonal boundary states of a macro region as input to an FE model. To exemplify this scaling process, a sophisticated local FE model for a composite beam-column joint with welded connections is used to derive the macro constitutive law of a plane rectangular macro element, which is then applied in the analysis of a 2-storey 2-bay frame under horizontal loading. The extension to cyclic loading is discussed and so are the implications for practical frame analysis in the future.

A generic finite element model for composite beam-column joints with welded connections has been developed using current state-of-the-art local modeling. Using mechanically consistent scaling, it provides the constitutive relationship for a plane rectangular macro element with beam-type boundaries that can be used in highaccuracy frame analysis. Global geometric variables allow the generation of specific FE models for each instance of a joint. Using assumptions typical for most composite frames, the constitutive relationship of the macro element can be represented by bilinear laws for the macro bending and shear states which are then coupled by a twosurface law with yield and failure surfaces. This is demonstrated in an example.

The spatial variability of input ground motion at supporting foundations plays a key role in the structural response of cable-stayed bridges (CSBs); therefore, spatial variation effects should be included in the analysis and design of effective vibration control systems. The control of CSBs represents a challenging and unique problem, with many complexities in modeling, control design and implementation, since the control system should be designed not only to mitigate the dynamic component of the structural response but also to counteract the effects of the pseudo-static component of the response. The spatial variability effects on the feasibility and efficiency of seismic control systems for the vibration control of CSBs are investigated in this paper. The assumption of uniform earthquake motion along the entire bridge may result in quantitative and qualitative differences in seismic response as compared with those produced by uniform motion at all supports. A systematic comparison of passive and active system performance in reducing the structural responses is performed, focusing on the effect of the spatially varying earthquake ground motion on the seismic response of a benchmark CSB model with different control strategies, and demonstrates the importance of accounting for the spatial variability of excitations.

The behavior of macro-elements can be described by a set of orthogonal boundary states, each consisting of displacements and forces associated by a one-dimensional constitutive relationship. Combinations thereof are described by surface models in the force space with flow rules. Local models describing the mechanics inside the element are not restricted in detail and are needed only once to develop the constitutive relationships, surfaces models and flow rules: The problem is scaled in a mechanically consistent manner without loosing information or accuracy. A macro-element for a plane beam-column connection has five orthogonal states: Two bending, two normal and one shear state, if linear boundary displacements are assumed. These "beam-type" boundaries enable the connection to any beam element. Thus, it can be included in regular frame analysis greatly improving its accuracy. To demonstrate this powerful scaling technique, typical component models for beam-column connections are used to develop a "beam-type" macro element.

Results of Experimental Investigations on the Load-Bearing Capacity of Steel Anchor Plates with in Concrete Encased Headed Studs in Reinforced Narrow Concrete ColumnsAnchor plates with welded shear studs are often used to transfer high loads from steel to reinforced concrete elements This is for example the case for the fixation of steel beams to reinforced concrete columns The anchor plates are fixed on site on the formwork and cast in-place in the concreteThe design is calculated according to European Technical Approvals [1], [2] like the design of post-installed anchors In contrast to post-installed fastenings, the utilisation of the reinforcement of in concrete encased headed studs is theoretically possible But the regulations of the ETAs lead to great reductions in the analysed load-bearing capacities compared to the capacities, obtained in tests. These tests have been conducted to investigate the load bearing behaviour and failure modes of anchor plates, especially in narrow reinforced concrete columnsIn the following article the results of the experimental investigations are presented, which show the influence of concrete compression strength, shear stud length, load eccentricity as well as amount and position of reinforcement

For development of testing facilities in Europe, the E-FAST project, a design study for a European Facility for Advanced Seismic Testing, is being carried out with the support of the European Union. Development and implementation of advanced algorithms for real-time substructure testing plays an important role in the design of the new facility. This paper presents two novel compensation methods that deal with destabilizing effects occurring in such tests: The unbalanced force at the end of a time step especially when implicit integration algorithms are used and the phase lag in hydraulic systems. Based on online system identification, the compensating value is estimated; the error of estimation is fed into an adaptive mechanism which adjusts system parameters and minimizes errors. For demonstration, substructure tests using a virtual 2-DOF structure combined with a real hydraulic testing system have been performed. The effectiveness of the compensations on accuracy and stability of substructure tests are discussed.

Today, mature beam-column connections exist for composite structures and their structural behaviour has been studied in many tests. Yet, it is still problematic to perform a detailed analysis even with the help of finite elements, let alone to include their results in the analysis of a complete frame. This keynote lecture first reviews current modelling approaches for typical composite beam-column connections under static and cyclic (e.g. earthquake) loading and their problems and limitations. It then presents a scaling concept that combines sophisticated local models with a broader frame analysis using a macro-element approach. The local models may be provided by and maintained at different institutions that broadcast their results on demand to a user performing a frame analysis. Thus, up-to-date state-of-the-art knowledge on local behaviour can be included in a design environment without prohibitive modelling effort. D