Modern design codes recalls the importance of the infill masonry (IM) walls in the design and assessment of buildings. But, it is recognized that the available guidelines and knowledge is still limited, particularly considering the complex in-plane and out-of-plane walls' responses and their interaction. Recent earthquakes in southern European regions showed that the damage on these non-structural elements can cause important human and economic losses. IM walls can influence the global behavior and performance of building structures, in terms of global lateral stiffness, strength, energy dissipation and ductility, but can also chance the distribution of seismic demands among the structural elements. To improve the seismic behavior and safety of existing building structures, in the last years, various solutions have been proposed for their retrofitting and strengthening, lacking further validation.

This Mini-Symposium is focused on the recent research outputs on the studies of infill masonry walls behavior, their contribution to the buildings safety and response, to the new techniques and solutions adopted in construction of IM walls and in the retrofitting of existing buildings, as well as on the design methodologies and detailing of IM walls concerning their seismic behavior

Existing structures designed without modern seismic design provisions represent one of the largest seismic safety concerns worldwide. Such structures are vulnerable to significant structural and non-structural damage and even collapse when subjected to medium-to-strong ground shaking. This resulted in number of fatalities and significant economic losses, which promoted the development of seismic assessment and retrofit procedures for existing structures.

Recent massive reconstruction processes pointed out the need for new, practical, and cost-effective seismic strengthening solutions. Over the past three decades, several techniques emerged. Fiber-reinforced polymer (FRP), High Performance Fiber Reinforced Cementitious Composites (HPFRCC) composites, base isolation, dissipative devices, low-damage systems gained popularity as attractive solutions for repair and retrofit of civil infrastructures. They are successfully used for strengthening/rehabilitation of existing buildings and bridges. However further research effort is needed to improve their effectiveness, develop new applications, numerical modelling, design procedures, and techniques for installation. The use of advanced materials and repair/retrofit techniques will continue to grow to meet the demands of the construction industry and seismic designers.

In this context, the mini symposium intends to attract academic staff, researchers, post-graduate students and professional engineers dealing with seismic repair and retrofit of structures, such as buildings and bridges, with innovative materials or with innovative seismic devices. The refinements in the analysis, design procedures and numerical modeling of repair/retrofit interventions are also of particular interest.

Significant developments have been made, in the last few decades, to provide more accurate and reliable design methods for structures, infrastructures and foundations, particularly, when subjected to dynamic (mainly seismic) actions. Numerical methods have played a major role in these advances. Nevertheless, their remarkable potential should be broadened and improved, since geotechnical earthquake engineering hazards are still difficult to mitigate.

The Mini-Symposium “Recent advances and challenges in geotechnical earthquake engineering” will offer an opportunity for the presentation and discussion on several geotechnical earthquake engineering issues. All those involved with computational mechanics, related to geotechnical earthquake engineering, are welcome to present their recent experience and research findings. Contributions related to hybrid, analytical, as well as, experimental methods in the field of soil dynamics and earthquake engineering are also welcome.

This Mini-Symposium aims to attract academic staff, researchers, post-graduate students and professional engineers dealing with advanced topics, which include but are not limited to: Performance-based design; Liquefaction and other types of major soil failures; Dynamic soil-structure interaction; Codes, standards and safety evaluation; Foundations and Ground Improvement; Retaining structures; Slopes, dams and embankments; Tunnels and lifelines; Wind turbines; Man-made vibrations.

Historical masonry constructions are typically complex structures, whose behaviour under earthquakes is still an open issue in the field of Structural and Seismic Engineering. In fact, considering that historical structures are more massive than modern ones and they were not conceived to withstand seismic actions, these constructions must be carefully evaluated in order to individuate their criticalities, so to design possible upgrading or retrofitting intervention techniques. The successful modeling of ancient masonries is a fundamental prerequisite for reliable earthquakeresistant assessment. The seismic behaviour of old masonry structures is, however, particularly difficult to be examined, because it depends on many factors, such as material properties, geometry, stiffness of the floors and the connection among orthogonal walls. In particular, masonry is a heterogeneous material, whose behaviour depends on several features, namely mechanical characteristics of matrix and inclusions, interface properties, in-plane texture, out-of-plane composition, etc.

In this framework, during the last decades, the scientific community developed different approaches both to model historical masonry constructions and to design retrofit interventions. On one hand, a comprehensive overview of methods (dynamic analytical methods, limit state methods, finite element methods, discrete element methods, etc.) for modeling of old masonries, starting from simple traditional techniques to modern ones used in computer programs, is still requested to evaluate level of accuracy, quantity of input data and calculation time for each of them. On the other hand, with reference to restoration and consolidation interventions, it is also requested to collect the wide series of traditional techniques and innovative ones in order to inspect their main prerequisites and drawbacks.

Based on the above premises, the main aims of this mini-symposium is to discuss the new advances in numerical modelling and seismic upgrading and retrofitting of masonry constructions with specific applications to historical masonry monuments.

Topics to be covered, but not limited to, are:

• Advanced numerical models
• Seismic assessment of historical constructions
• New strategies for the preservation of heritage structures (SHM, damage detection, …)
• Nonlinear static and dynamic analysis
• Incremental Dynamic Analysis applied to historical structures
• Constitutive models for masonry materials
• Homogenization techniques
• Multi-scale analysis
• Large-scale seismic vulnerability analysis
• Repairing and retrofitting interventions
• Novel restoration techniques
• Integrated seismic-energy consolidation systems

This Minisymposium is aimed at presenting the recent state-of-the-art works on the earthquake vulnerability in terms of local collapse mechanisms, such as the out-of-plane behaviour of URM walls, parapets, chimneys, prefab concrete walls, non-structural elements behaving as rigid in buildings and industrial facilities. All those involved with the local seismic response of rigid structures using advanced and simplified evaluation methods, such as force-based and displacement-based techniques, limit analysis, FEM-based procedures, as well as discrete element methods and rigid block modelling approaches, are welcome to present their recent experience and research findings. Contributions related to the mutual interaction between the in-plane and out-of-plane behaviour of URM walls, the dynamics of different types of rocking structures, as well as experimental investigations in static and dynamic fields of rigid blocks, probabilistic approaches and current SSI-approaches for rigid block models are also well accepted.

This Minisymposium will focus on, but is not limited to, the following topics:

• Analytical and computational strategies for the identification of local mechanisms
• In-plane and out-of-plane behaviour of masonry structures
• Visual programming for local mechanisms
• Analytical and experimental contact mechanics
• Experimental seismic performance of local mechanisms
• Probabilistic approaches in rocking analysis
• Energy dissipaters for rocking structures
• Rocking response of masonry and concrete walls to earthquakes
• Smooth and non-smooth rocking problems
• Characterisation of seismic input for local mechanisms
• Consideration of the soil-structure interaction in rigid block models of masonry structures
• Case studies

Masonry infills are traditionally inserted in reinforced concrete or steel frame structures as partition elements and to separate the internal and external environments. During seismic events, infills strongly interact with primary structures, significantly influencing strength, stiffness, collapse modes, and structural ductility. Research in the field of infilled frames has been carried out for more than 60 years. However, several issues are still open regarding computational modeling, in-plane/out-of-plane response interaction, the seismic performance of new and existing buildings, the influence of infills on structural robustness, and EAL assessment.

This mini-symposium encourages the submission of papers presenting new findings in the field of computational modeling and the experimental testing of the in-plane and/or out-of-plane response of infilled frames, and new advances in the assessment of their seismic response or their contribution to structural robustness.

Topics to be covered, but not limited to, are:

• In-plane / out-of-plane interaction;
• Infill/frame local interaction;
• Experimental tests;
• Innovative technologies for masonry infills;
• New proposals for macro-modelling of infilled frames;
• Reliability and expected annual loss evaluation of infilled frames
• Results of FEM analyses and analytical studies;
• Simulation of case studies via nonlinear static or dynamic analyses;
• Fragility assessments;
• Strategies for repairing damaged infills and related computational issues;
• Robustness of infilled frame structures.

The interaction of earthquakes with the complex and vulnerable socio-economic system of exposed communities often results in damage and loss, sometimes with catastrophic consequences. As also strongly stated by the Sendai Framework for Disaster Risk Reduction, understanding disaster risk is the first priority in the pursuit of a global strategy for risk reduction. Furthermore, the implementation of risk monitoring and early warning systems is one of the viable solutions to actively prevent or reduce damage to specific structures, or even to whole regions.

The determination of seismic risk is the foundation for risk mitigation decision-making, a key step in risk management. Large corporations and other enterprises (e.g., local governments) analyze their 'portfolio' of properties, to determine how to best allocate limited funds for structural strengthening of buildings, or other risk reduction measures such as emergency planning. When assessing the seismic vulnerability of buildings, it is essential to first establish the project objectives, before subsequently choosing the most appropriate strategy and tools necessary for building assessment and fulfillment of these objectives. It is also extremely important to understand the difference between the detailed approaches used for individual building assessment and those methods most efficient for larger scale analysis, pursued for city center assessment. While the latter results can be used as a general measure of seismic risk for different types of buildings, the actual seismic risk for any individual building may vary considerably and will depend upon its exact configuration and condition. This Minisymposium will deal with: 

Modeling the potential impact of earthquakes in terms of damage to physical assets, loss of life and livelihoods, economic consequences and functional disruption of infrastructure;
Understanding the underlying uncertainties in the modeling process, and the role of these uncertainties in the subsequent seismic risk management phase;
Devising innovative methodologies to efficiently collect and integrate the information needed in order to reliably carry out seismic risk assessment and impact forecasting at different spatial scales.
Exploration of the modeling of cumulative damaging mechanism and the effect of vulnerability interaction.

A large part of the existing Reinforced Concrete (RC) building stock in seismic areas has not been designed in compliance with contemporary earthquake engineering principles (e.g., the Capacity Design approach), which are aimed at ensuring, under seismic action, proper ductility in the structural response at global and local level, preventing the onset of undesired, brittle failure mechanisms, thus providing to the buildings enough ductility to dissipate energy withstanding large deformations into inelastic field without collapsing. As a result, as confirmed by the field observations following recent seismic events in European countries (e.g., L’Aquila 2009, Lorca 2011, Central Italy 2016), the seismic performance of existing RC buildings under moderate-to-large earthquakes is often characterized by very significant structural damage, up to disastrous collapses, leading to high human, functionality and financial losses. Hence, the development of capacity models for displacement-based assessment and nonlinear modelling of this kind of RC elements – often referred to as “substandard” or “non-conforming” – is a key issue both for pre-normative research and for seismic vulnerability/fragility analysis of existing buildings, also within a performance-based approach to the design of strengthening/retrofit solutions. The research in this field, aimed at the study and proposal of more refined and reliable models, is of particular interest for earthquake engineering, as demonstrated also by the current, continuous development and updating of technical standards (e.g., Eurocode 8 – part 3, ASCE/SEI 41, NZSEE Guidelines). The present Minisymposium is aimed at collecting and discussing contributions focused on the response under seismic action of existing RC elements, controlled by different collapse mechanisms including non-ductile failure modes, including, in particular, (i) pre-normative research studies regarding models for the assessment of strength and deformation capacity and (ii) approaches to nonlinear modelling of their behavior.

The art works represent a priceless asset of our cultural capital, since they play a crucial role in defining and understanding the identity of communities. Nevertheless, they are not always adequately protected against possible dangers, such as earthquakes. In these last decades, the seismic protection of art works has been gaining an increasing attention, involving multidisciplinary approaches which collect new technologies - such as the digital control, the 3D reconstructions etc. – together with the most advanced structural analyses. This session aims to collect advanced contributions from academics, researchers, students, post-graduate students and professional engineers dealing with the seismic assessment and protection of art collections. All the steps involved in the process aimed at determining the response of art works subjected to dynamic excitations are included in the session.

The main topics faced by the session include:
- Classification criteria aimed at protecting art collections;
- Simplified modeling of art works;
- FEM analysis of art works;
- Experimental analysis of artifacts;
- Design of proper devices for the seismic reliability of artifacts;
- Application to real case-studies

The significant amount of economic losses supported by governments after the recent earthquakes has caused a growing interest on the impact of retrofit strategies on the structural behavior with the aim of seismic risk reduction. An effective seismic retrofit requires a reliable assessment of the as-built condition. Several open issues still exist about the modelling and seismic assessment of low-standard existing reinforced concrete (RC) buildings, from the nonlinear hysteretic response characterization of their (above all) shear-critical elements, the frame interaction with masonry infills, the proper definition of damage states or failure criteria and of related fragility curves, to a reliable estimation of seismic economic losses for such buildings. Most of these aspects were recently addressed by researchers worldwide, to provide reliable modelling and analysis tools, both for extensive numerical analyses on a single case-study existing RC building or for large-scale vulnerability assessment of RC building stocks.

Most of these issues have been recently dealt with also for retrofitted buildings, often at a component level. However, significant efforts are still necessary to overcome the simple compliance with codes requirements and reliably reproduce and quantify in numerical analyses the structural benefits of retrofitting strategies due to an earthquake scenario. These efforts will allow both providing a key overview for selecting the best (traditional or innovative) retrofitting strategy, and, in a near future, facing up, as researchers or practitioners, the issue of seismic assessment of existing retrofitted structures.

This mini-symposium aims to discuss about the recent advances in nonlinear modelling and seismic assessment of as-built and retrofitted existing RC buildings and share them with the scientific community. The welcome topics include, but are not limited to: the proposals of refined or simplified modelling tools for existing RC buildings, the modelling and nonlinear analyses of as-built-versus-retrofitted buildings, the definition of failure criteria in both as-built or retrofitted conditions, the estimation of performance benefits of retrofitted buildings with respect to their as-built condition and the related update in terms of fragility curves, case-study applications, large-scale vulnerability assessments.

Existing structures designed without modern seismic design provisions raise great concern worldwide. Such structures exhibit often significant structural and non-structural damage and even collapse when subjected to medium-to-strong ground shakings. This results in a fatal loss in terms of human lives and a strong economic and downtime effort. Strategic reinforcement of these structures can effectively reduce seismic risk, and specific optimization strategies improve the effectiveness of the interventions.

This mini-symposium encourages the submission of papers presenting new findings in the field of computational modeling, experimental testing and optimization of seismic retrofitting/reinforcement systems, with special interest to reinforced concrete and masonry structures.

Topics to be covered, but not limited to, are related:

• Seismic retrofitting/reinforcement by FRP and FRC systems
• Steel Jacketing – Concrete Jacketing – Prestressing
• Base isolation and dissipation of existing buildings
• Innovative retrofitting/reinforcement systems
• Case studies
• Analytical methods for simplified modelling and analysis
• Artificial intelligence algorithms for retrofitting/reinforcing optimization
• Expected annual loss evaluations of retrofitted/reinforced structures

Time history analysis is a key tool in earthquake engineering research, as well as practical nonlinear seismic analysis. The existing approaches for time history analysis are however approximate and time-consuming. The case becomes worse when many seismic analyses are under study, e.g. incremental dynamic analysis or fragility analysis. The objective of this mini-symposium is to bring together researchers and scientists from around the globe to present and discuss their studies’ results on more efficient time history analysis in the friendly environment provided by COMPDYN2021 conference. Contributions addressing new achievements on more efficient time history analysis against seismic excitation, including more accuracy, less run-time, less memory-storage, different reduction methods, and considering near or far field records, linear or nonlinear, different nonlinearities, different structural systems and behaviors, different types of analyses, different regulations of the seismic codes, different integration methods, aftershocks, etc. are very welcome to this mini-symposium. The organizer of this mini-symposium sincerely hopes the attendees to this mini-symposium can leave COMPDYN2021 and Athens, with good memories also from the mini-symposium, as well as new ideas and suggestions for mutual collaborations.

Railways are an essential part of the transportation infrastructure and are therefore critical for the wealth and well-being of society. Consequently, the development of accurate and reliable design methods is a topic of major importance, in addition to proper validation of such methods against experimental results or field measurements. Traditional design methods in Railway Engineering are very often based on static approximations of a highly dynamic problem. Recent research has shown that under certain conditions, such as low speeds, well aligned rails, rails on stiff ground, etc. a static approximation is a reasonably reliable design assumption. Modern railways, however, are often designed for high-speed operation, while they may cross ground formations of variable stiffness and strength characteristics. Consequently, simplified computational methods could yield to uneconomical, unecological or raise safety issues. Therefore, railway industry calls for high-performance engineering considering appropriately the dynamic effects.

This mini symposium encourages the submission of papers presenting new findings in the field of dynamic response assessment in rail track engineering.

Topics cover, but are not limited to:

• vehicle-track-soil interaction,
• vehicle-track-bridge interaction,
• structure-borne and air-borne noise,
• ground-borne noise and vibration.

Papers of latest findings of relevant research, as well as case studies from industry and high-tech engineering, are very welcome.

Since it was observed that rocking structures behaved unexpectedly well in the 1960 Chilean earthquake, research on rocking is proliferating with applications in: designing of resilient buildings and bridges that are intentionally designed to uplift and use rocking as a seismic isolation method; evaluating the stability of ancient monuments; exploring the behavior of equipment, components, and nuclear waste containers; and understanding the behavior of masonry. This minisymposium aims to attract recent analytical, numerical, and experimental contributions on the behavior of rocking and articulated structures.

Slenderness and lightness of modern large structures (such as tall buildings and long-span bridges) can pose unprecedented challenges in the design and control under dynamic loads. For instance, it can be required to cope with unexpected large seismic demands when designing tall buildings and long-span bridges that might be subjected to pulse-like ground motions characterized by unusual high spectral values in long periods domain. The mitigation of the dynamic response of tall buildings and long-span bridges is also a key issue in order to meet more and more stringent serviceability and safety requirements. In this perspective, structural optimization provides powerful tools to determine the most effective solutions able to reduce environmental and economic impacts of large structures while fulfilling imposed aesthetic criteria and enhancing the overall mechanical performance. Therefore, this minisymposium aims at bringing together researchers and practitioners in such a way to foster the exchange of most recent ideas and experiences about the optimum design and control of large structures under dynamic loads.

Topics of interest include (but are not limited to) the following themes:

• characterization of dynamic loading conditions especially relevant for large structures; 
• optimum design of large structures under dynamic loads;
• optimization of devices for vibrations control in large structures;
• advanced algorithms and computational technologies in the optimum design and control of large structures under dynamic loads. 

This Mini-Symposium is aimed at investigating the mechanics of tensegrity structures and their employment in the computational design and modeling of mechanical metamaterials, biological systems and bio-inspired structures.

A first area of research regards the employment of tensegrity metamaterials to create periodic lattice structures with unconventional mechanical properties. Examples of the targeted systems include, but are not limited to, prestress-tunable tensegrity metamaterials; nonlinear lattices with softening and stiffening responses; next-generation actuators and tensors; novel bandgap and seismic metamaterials; soft-robots and deployable space structures. The MS is also interested in the use of tensegrity structures to model the mechanics of biological and bio-inspired systems, including, e.g., living cells, spider dragline silk, the mechanics of bones, muscles and tendons; and bio-inspired fibers with enhanced strength and toughness.

Multifunctional tensegrity lattices are studied at the nano-, micro- and macro-scales, with a focus on their development in scientific fields where current knowledge of such systems is either partial or consolidated. We also welcome contributions around tensegrity-inspired structures and discrete systems, whose mechanical properties can be customized by changing geometry, connectivity, and/or internal and external prestress.

This MS aims at providing a platform for idea exchange and knowledge dissemination vis-àvis the latest developments in the field of condition-based maintenance and post-prognostics decision-making of complex composite structures. Global industrial and academic stakeholders have long recognized the need for the development of robust workflows to be able to i) detect damage, preferably during operation of a structure, ii) identify the type and size of the detected damage, and iii) quantify its criticality through estimating the remaining operational time of the structure. Focal point of these objectives is the accurate representation of damaged segments via data and/ or physics driven approaches.

Topics relevant to the Mini symposium include, but are not limited to, implementations and algorithmic solutions for:

- Wave interaction with damage modelling
- Damage detection methods for industrial composites
- Bayesian and AI identification methods
- Physics and data-driven prognostics modelling
-Structural Health Monitoring solutions, including built-in sensors and devices
-Prognostics algorithm embedment within IoT technology Contributions pertaining to the implementation of such methods on real-life applications are especially welcomed.

This MS is organized within the framework of the ENHAnCE MSC Innovative Training Network.

The objectives of the minisymposium are to present and discuss state-of-the-art mathematical models, numerical methods and computational techniques for the solution of practical problems in dynamics. The topics of interest include solution methods for structural dynamics, wave propagation, contact-impact, partitioned solution strategies and coupled problems of multidisciplinary character in science and engineering. Numerical works on dynamic systems (linear/nonlinear, holonomic/non-holonomic, deterministic/stochastic) and wave propagation for smart and advanced materials or structures are also welcome.

Emphasis will be on the discussion of accuracy, robustness and performance of the proposed models and numerical techniques, as well as comparison with other classical numerical methods and available experiments.

In definitive, the minisymposium goal is to share ideas and contribute for advances in the formulation and numerical solution of challenging dynamic problems, with a multidisciplinary vision and accounting for all the complexities involved in the physical description of real-life problems.

Life-Cycle Cost Analysis (LCCA) is an approach that has gained popularity for assisting the design of civil structures and infrastructures. LCCA advantageously supplements the traditional design approach by: i) allowing the consideration of all costs and losses incurred during design, construction and management throughout structural lifetime; ii) accounting for uncertainties in structural modeling and load characterization; and iii) enabling the inclusion of progressive ageing and damage models for materials and components. The LCCA approach can also be leveraged for structures equipped with Structural Health Monitoring (SHM) systems and control systems (i.e. “smart structures”) to quantify long-term benefits of each technology and support long-term implementation. Such quantification can be conducted by computing the benefits of condition-based maintenance, enabled through the early detection and quantification of damage.

In this framework, the Minisymposium aims at presenting recent advances, exchanging experiences, transferring knowledge and stimulating dialogue among experts and researchers in the areas of risk assessment, LCCA and resilience of structures, infrastructures subjected to single or multiple hazards and/or materials deterioration due to ageing, with specific attention (i) to bridges and infrastructures management, (ii) to deteriorating/ageing monumental buildings, (iii) to the use of structural health monitoring systems as tools for optimal maintenance planning, (iv) to the development of computational methods for risk analysis, (v) to sustainability and community resilience.

Prerogatives of easiness and quickness of construction, transportation, material sustainability, energy efficiency and good seismic response make timber structures a valid alternative with respect to traditional systems.

The introduction of new engineered timber products (Glulam, Cross Lam, Laminated Veneer Lumber, etc.) has offered new possibilities and encouraged a massive use of timber-based elements in the last decades, making it a material with wide possibilities of use. In addition to long-span roofs or bridges, timber elements are effectively used to realize highly-performing timber buildings for commercial and residential destinations in the seismic-prone area. The good seismic response offered by these constructions, together with their prerogatives of environmental sustainability, have encouraged the use of timber buildings not only in those countries particularly devoted to the timber practice (i.e., North America, Japan, Australia, and North Europe) but also in the Mediterranean area.

Nowadays, studies concerning alternative employments of timber elements are ongoing by the scientific community. Among these, timber elements - such as panels, braced systems, or similar - used as additional eso or endoskeletons for seismic retrofit of existing masonry and reinforced concrete buildings could constitute effective solutions able to combine seismic and energetic retrofit requirements.

This minisymposium welcomes contributions that focus on (i) theoretical, experimental and numerical results concerning the seismic behaviour of engineered timber buildings and its subassemblies; (ii) seismic behaviour of mechanical and carpentry connections and their effect on the overall seismic response of the buildings; (iii) use of timber for retrofitting of existing masonry and reinforced concrete buildings; (iv) restoration techniques for ancient timber structures in seismic-prone area; (v) codes practices: recent advancements and urgent needs.

The recent advances in numerical simulation methods allow to consider the assessment soil-structure-interaction (SSI) effects inside multidimensional systems. The most historical approaches performed linear analyses that are generally appropriate to describe low amplitude ground motions, but they are not able to address non-linear effects of the system. In this regard, performing SSI-based approaches is fundamental to assess non-linear soil mechanisms that are at the base of complex responses of the so called soil-foundation-structure-interaction (SFSI). 

This mini-symposium focusses on new research and case studies that explore both SSI and SFSI numerical simulation approaches. Results from large scale field tests and case histories from past earthquakes are used as the basis to assess numerical simulation approaches. Both small strain SSI based modelling and large strain SFSI modelling outcomes will be presented, highlighting the effectiveness of current simulation techniques.

Recent post-seismic surveys have shown that the losses induced by the damage to non-structural components are enormous and mitigation measures have been scarcely implemented. Furthermore, the design and assessment procedures for non-structural components, especially freestanding, are either at an early stage or require comprehensive numerical and experimental validations. Testing protocols for the qualification of freestanding components are available, but further refinements are also deemed necessary to improve their effectiveness. Finally, the efficacy of mitigation devices and techniques for non-structural components requires extensive experimental tests, which are still lacking.

The MS welcomes contributions that focus on the recent advances on the seismic protection of non-structural components. It is open to a variety of topics, including (but not restricted to):

• Anchored components;
• Freestanding contents;
• Existing numerical approaches: current limitations and possible future improvements;
• Advanced design and assessment procedures;
• Modern technologies and procedures for seismic protection;
• Experimental tests: static and/or dynamic characterization, earthquake response, testing protocols and qualification procedures;
• Code of practice: existing provisions and urgent needs.
• Measures for the seismic protection of artefacts.

Dynamic protection systems and devices, such as seismic isolation bearings and dampers, are characterized by a complex nonlinear behavior which typically exhibit a rate-dependent and/or a rate-independent hysteretic nature.

In order to encourage the use of such innovative systems and devices in practice, researchers not only need to perform a significant number of experimental tests, required to study their actual nonlinear behavior, but they also have to develop accurate and efficient mathematical models and design procedures.  

The purpose of the Mini-Symposium is to share most recent advances related to the following issues:

• Experimental Studies: experimental tests results describing the behavior of novel and existing dynamic protective systems and devices; experimental verification of numerical methods and mathematical models; experimental calibration of nonlinear models parameters.
• Mathematical Modeling: solution strategies and numerical methods to perform nonlinear structural analyses; mathematical models devoted to simulate the nonlinear behavior of dynamic protective systems and devices; model parameters identification procedures; simulations performed by adopting existing computer programs, such as OpenSees, MIDAS, Sap2000, and 3D-BASIS.
• Structural Design: design strategies for structures and equipment with dynamic protection systems: active, passive, semi-active, and hybrid control systems; optimization design methods; case studies of challenging applications.

Award for the best young presentation during the Mini-Symposium

In order to stimulate the active presence of young people, the organizers have decided to reward the best presentation of a young researcher under 35 (at the start date of the conference). The interested ones should state their age.

Virtual models of engineering structures, so-called Digital Twins, are widely used from the preliminary design stages to the operating structural life-time assessment. However, one of the key challenges in developing reliable Digital Twins of structures subject to dynamic operational and environmental loads is using an appropriate damping model for the structural components and joints. Quantifying damping and its variability experimentally, both in laboratory and in operating conditions is particularly important in order to improve the Digital Twins for structural health monitoring applications.

This MS invites contributions on fundamental work, advanced techniques and industrial applications showcasing recent progress on damping (including friction, constrained layer damping and other damping methods) characterisation and modelling for Digital Twins. 

Topics of interest include:

• Experimental techniques to characterize damping;
• Validation of damping models;
• Damping and friction mechanisms in mechanical joints;
• New damping strategies.
• Damping uncertainty quantification

Evaluation of building performance due to earthquakes is crucial for the estimation of potential seismic losses and to enhance preparedness and prevention actions towards more resilient communities. While most refined analytical assessment methods, relying on detailed finite elements model of a building, allow the accurate study of single buildings response, simplified approaches are needed for territorial scale investigations, involving large building portfolios in a region of interest. Several simplified performance-based assessment procedures have been proposed and applied over the past decades to quantify response and related losses both at building and regional scale, encompassing approaches for simplified structural analysis, the use of fragility functions for building typologies, the development of damage functions and the calibration of cost functions for relevant building types and components. Performance-based frameworks for simplified loss assessment allow also to evaluate the effect of application of retrofit interventions towards seismic risk reduction for single buildings or at territorial scale.

The objective of this mini-symposium is to share and discuss research results and ideas on simplified approaches for building performance and loss assessment. Relevant topics include, but are not limited to:

• The use of simplified models for simulating seismic response and performance
• Frameworks and/or applications for simplified loss assessment at building or territorial scale
• Evaluation of damage and consequence functions towards simplified loss assessment

Papers that address conceptual, theoretical, computational, and/or methodological developments towards simplified performance and/or loss assessment for as built and/or retrofitted buildings, as well as novel and/or large-scale applications, are welcome.

A paper submitted in this Mini-Symposium should have a content that combines numerical simulations of various problems that belong in the field of Earthquake Engineering and Structural Dynamics with relevant experimental studies through laboratory or in-situ measurements. Particular applications may belong to dynamic and earthquake response of structures and components, influences arising from seismic retrofitting towards upgrading the dynamic and earthquake performance of structures and components as well as earthquake protection measures from various forms of base isolation, damping or energy dissipation devices for controlling the dynamic and earthquake response of structures and components. Moreover, in-situ or laboratory measurements dealing with influences arising from soil-structure interaction during the dynamic / earthquake response of structural systems accompanied by relevant numerical simulations are also included. Fields of application may include a variety of modern structures or cultural heritage structures constructed with a variety of materials including steel, reinforced concrete, masonry etc.

Fragility curves constitute an essential tool for reliable seismic risk assessments. In the last decade, the number of researches addressed to define them considerably increased and the analytical/numerical methods have developed more and more alongside those based on the empirical approach. Each method has pros and cons and selecting one of them depends on many factors, first of all the actual data available on the building stock under examination. Various literature works have highlighted as results may turn out very different, thus leading – when used for risk analyses - to potentially large differences in the estimation of the consequences and, in turn, of the resulting mitigation strategies. Aware of that, various actions at international (e.g. the Global Earthquake Model Foundation) and national (e.g. in Italy the MARS project funded by the Italian Department of Civil Protection aimed to develop national Seismic Risk Maps) scale are committed to overcoming these limits.

Within this context, this mini-symposium aims to provide an occasion for researchers for sharing their knowledge and experience and discussing about new trends on:

• the critical issues intrinsic in the aforementioned methods (i.e. analytical, numerical and empirical ones);
• how cross-checking the fragility curves derived from different methods;
• how integrating results from different methods in order to improve the reliability and accuracy of risk analyses.

The focus is on existing stocks of different structural typologies (e.g. RC, URM, …), paying special attention to the different perspective that the development of fragility curves implies for residential buildings, spread in the territory, or for portfolio of specific typologies (e.g. schools, hospitals, …).

An effective way of protecting structures against the devastating effects of earthquakes, and achieving a desired level of performance, is to mitigate the seismic demand on the system itself. To this end, viable solutions identified over the past few decades include the use of passive systems for vibration control based on the concepts of base isolation and supplemental damping. The effectiveness of these strategies has been demonstrated extensively, via numerical analysis and through laboratory experiments, and structures equipped with base isolators and/or dampers have performed well over the course of past earthquakes.

Notwithstanding their many benefits on the seismic performance of structures, currently available systems can be affected by limitations of various nature. Thus, the pursuit of enhanced solutions and/or more effective systems is the object of ongoing cutting-edge research.

The scope of this Minisymposium is to collect experiences and proposals.

The Minisymposium aims at drawing the interest of academics, researchers and manufacturers, by displaying progresses and highlighting research needs in the field of seismic mitigation techniques, and presenting the most recent contributions with respect to improving current technologies for vibration control of structures.

Relevant topics include, but are not limited to:

• novel base isolation systems;
• response of isolation systems under extreme loading conditions;
• use of isolation systems in combination with gap dampers and/or tuned mass dampers;
• dampers with adaptive response;
• advances in numerical modelling of seismic isolation and energy dissipation systems.

Papers that address conceptual, theoretical, computational, and/or methodological developments to expand base isolation and energy dissipation towards innovative solutions, as well as novel and/or large-scale applications, are welcome.

The recent seismic disastrous events have been highlighted that the structures and infrastructures damage (public, private and strategic) are the main reason of the significant direct and indirect losses. Seismic risk mitigation is became a great problem for seismic prone countries and their decision makers. It needs to be solved in complex communities governed by complex processes, where often urban planning, socioeconomic dynamics, and the need to preserve cultural assets are present simultaneously. The seismic risk mitigation must be considered as the main topic in the governance of communities. Nevertheless, due to limited financial resources (if compare with the high levels of lossess), mitigation activities have often been limited. At this point, a significant change in point of view is necessary.

In recent years, in order to provide support for public administrations, private, insurance companies, banks, owners and professionals, despite operating at different territorial scales, several studies have been conducted based on the concepts of resilience of communities, rational and effective management criteria.

In accordance with the objective of risks analysis and territorial scale (until the analysis on single buildings), different kinds of direct and indirect losses can be considered.

The proposed Minisymposia would like to show and compare different approaches, existing operative proposals, and cases study about the following (but not limited) topics:

• Risk Assessment.
• Seismic Hazard Analysis.
• Critical Infrastructure Protection.
• Innovative, simple, fast, readily available, and economically sustainable retrofitting strategies and optimised rules for planning.
• Definition of rational criteria for risk-mitigation policies.
• Allocation of the resources based on novel approaches and methods.
• Structural control, monitoring and assessment of structural damage
• Seismic vulnerability assessment and retrofit of structures.
• Case Studies.

Safety of bridges and road networks is of paramount importance since their disruption might have high socio-economic impact as well their collapse could seriously endanger people life. For this reason, it is important to assess the vulnerability of this type of infrastructures against various sources of hazards: flood-induced scour, landslides, wind, hurricanes, earthquakes.

Moreover, the effect of ageing, poor maintenance, lack of knowledge and outdated design criteria (i.e. not-updated traffic loads or non-seismic design) make these systems among the most vulnerable elements of the network infrastructure.

An accurate capacity assessment of existing bridges is thus extremely important for characterizing the main structural deficiencies, estimating the risk and prioritizing retrofit interventions to improve the system resilience.

Based on these premises, this Special Session offers the opportunity to present and discuss the last researches on this wide topic, and contributions addressing experimental, computational, and methodological developments are welcome, as well as proposals of:

- numerical and predictive models suitable for bridge risk assessment;

- new techniques of monitoring and testing;

- multi-hazard risk assessment and probabilistic analysis;

- innovative techniques for seismic isolation or energy dissipation for bridges;

- applications and case studies

Recent advancements on the dynamic response of structures have highlighted that soil-foundation-structure interaction may be important for the design of geotechnical systems, including retaining walls and foundations of structures, and of critical infrastructures such as bridge piers and offshore wind turbines, under earthquake or other dynamic loading. Support on the above issue has been provided by relevant theoretical studies, experimental recordings at real or laboratory scale and field data from instrumented foundation-structure systems and post-earthquake reconnaissance surveys.

Along these lines, this Minisymposium encourages contributions on the dynamic analysis and design of retaining walls, surface and deep foundations or other engineering solutions including soil improvement, geotechnical isolation etc. Emphasis will be primarily (but not exclusively) given to: (i) Theoretical and/or numerical studies on the dynamic response of  soil-structure systems (ii) Real instrumented sites of foundations and their supporting structure (iii) Field or laboratory tests on novel foundation systems and interpretation of recorded data. Studies on specific topics such as kinematic soil-foundation interaction and the behavior of foundations in complex soil conditions are particularly welcome.

It is envisioned that this Minisymposium will create an interacting forum among scientists and practitioners to exchange knowledge and new research ideas on the analysis and design of geostructures under dynamic loads.

Seismic risk assessment is an essential first step in any disaster prevention activity. The first seismic risk assessment studies, in the late 1960s and early 1970s, defined the risk as a measure of the hazard. Nowadays, it is well recognised that the risk also depends on structural vulnerabilities and exposure issues and that the main interest focuses on economic issues. In this regard, many works recently focused on the concepts of fragility and vulnerability as well as on economic loss; usually, a probabilistic framework is adopted to account for uncertainties involved in the process.

Probabilistic frameworks for the seismic risk and loss estimation implement fragility curves that are affected by uncertainties relevant to adopted predictive numerical models and the definition of the seismic actions. Sources of inaccuracy can produce an unreliable seismic impact assessment, compromising the decision-making process for the risk mitigation and the improvement of the community resilience. Usually, only uncertainties relevant to seismic actions are addressed; however, also uncertainties relevant to the structural response can have a key role. The latter ranges from trivial issues due to geometry and mechanical properties of materials to more complex aspects such as the soil structure interaction, including possible site-structure resonance phenomena, which may be responsible for unexpected amplifications of the structural response. Recently, the research focuses on the use of dynamic tests and permanent monitoring (extended to both the structure and soil domain) as strategies for the reduction of uncertainties in the assessment of the seismic risk of structures. Dynamic tests and data from monitoring systems are more and more often adopted to improve the modelling of structures for simulations aimed to define the fragility of a specific structure or structural typologies. However, the use of data from dynamic tests should be differently handled, depending on tests and the structural typology, considering effects of environmental conditions and excitation levels.

The mini-symposium encourages the sharing of opinions and the presentation of recent studies concerning the role of dynamic tests and permanent monitoring on the seismic risk assessment and mitigation. Main topics are (but are not limited to):

- Implementation of monitoring and testing techniques on risk assessment frameworks;
- The role of dynamic tests in defining the seismic vulnerability of strategic structures and infrastructures (e.g. healthcare structure, school building, bridges, dams):
- Recent progress in dynamic identification techniques and automated operational modal analysis;
- ​Model updating, surrogate model and optimal placement sensors;
- Data from monitored full-scale case studies with emphasis on the effects of environmental conditions (temperature, wind, humidity ...) and excitation levels (non-linear response);
- Interpretation of data from monitoring systems and how to handle variations in modal parameters due to boundary conditions (e.g. physical and data-driven models, machine learning based methods);
- Data from monitored scaled structures or structural components (laboratory mock-up or specimens);
- Vibration based strategy for the assessment of the structural health and damage detection.

The use of Artificial Intelligence (AI) and Machine Learning (ML) algorithms in developing predictive models towards the design and assessment of structures is gaining significant momentum. This minisymposium aims to serve as an ideas exchange hub that will help scientists to share their current research work on AI and ML algorithms that have as a main objective the development of:

• design formulae,

• predictive models for the assessment of structures and materials,

• other predictive models that deal with the mechanical behaviour of structures.

One of the main objectives of this minisymposium is to generate a broad discussion on how AI and ML algorithms can be utilized in assisting towards establishing a safer built environment in both low and high seismically active countries.

Seismic isolation and energy dissipation devices are technologies widely employed for enhancing the seismic performance of structural and non-structural components. Their use is increasing not only for protecting critical structures, but also for ordinary ones, and particularly those needing retrofitting. Qualification tests and design and assessment methodologies are also well established. Nonetheless, novel devices and characterization tests are continuously developed, along with more advanced methodologies for the performance assessment and design, capable to account more rigorously for the uncertainty inherent to the evaluation of the seismic performance.

This Minisymposium aims at highlighting and discussing new developments and open research issues addressing experimental, computational, and methodological aspects of the performance of structures equipped with isolation and/or energy dissipation devices.

Contributions from researchers, manufacturers and practitioners are expected in (but not limited to) the following areas:

1) experimental and qualification testing of isolation/dissipation devices;

2) numerical modelling of the constitutive behavior of seismic isolation and energy dissipation devices;
3) design procedures for isolation/dissipation devices and structures equipped with them;

4) performance-based assessment of structures equipped with isolation/dissipation devices;
5) innovative isolation and energy dissipation devices;

6) structural health monitoring and dynamic identification of isolated structures and structures equipped with damping devices;

7) case studies or emblematic examples of implementation of isolation/dissipation technologies;

Model reduction techniques have been extensively used to improve the computational efficiency in various structural dynamics problems since the 1960s. Recently, they have been employed not only for conventional applications such as free vibration, transient analysis and finite element model updating, but also uncertainty quantifications, multiphysics problems, and design optimization. They can offer theoretical backgrounds of digital twin and virtual sensing in Industry 4.0 revolution. In particular, the model reduction society has been enthusiastic to data driven modeling and simulation with machine learning strategy. It may give a chance to real-time simulation in computational dynamics.

The aim of this mini-symposium is to provide a forum for researchers to discuss recent advances of model reduction techniques for the computational and structural dynamics community. The proposed MS invites researchers to present their research progresses on the following and related topics:

✓ Data driven real-time simulation with machine learning, meta (surrogate) modeling;

✓ Nonlinear reduced-order modeling, hyper reduction, POD–DEIM, Modal derivatives;

✓ ROM for multiphysics and multidisciplinary problems;

✓ Model reduction for stochastic model and/or optimization issues;

✓ New reduction and/or component mode synthesis;

✓ Dynamic substructuring, virtual sensing, FE model updating, system identification;

✓ Industrial applications of model reduction techniques; Linear and eigenvalue problem solution techniques (such as domain decomposition, FETI, AMLS, etc) are also welcome.

The proposed MS is devoted to collect new contributions from recent studies on the behavior, design, testing and analysis of steel joints subjected to cyclic loading in either elastic or plastic range. Indeed, the cyclic performance of steel joints significantly affects the overall response of steel and steel-composite structures, their safety margin as well as their constructional costs. Therefore, the main topic addressed by this MS will cover experimental and numerical analyses, design of the traditional and innovative joints typologies, cyclic response under seismic loading and fatigue.

The main topics will include:

• Design of steel and steel-composite joints;
• Innovative joint typologies;
• Monotonic and cyclic behavior of steel and steel-composite joints;
• Seismic behavior of steel and steel-composite joints;
• Fatigue performance;
• Advanced Finite element analyses;
• Non-linear structural analyses;
• Influence of joint’s behavior in the overall structural performance.

Megacities are continuously challenged by rapid rates of population increase, and upwards and outwards urban expansion often accompanied by infrastructure problems. Furthermore, many megacities are in parts of the world prone to multiple natural hazards, such as earthquakes, floods and landslides. Consequences and combined impact of these hazards are not evenly distributed, as accumulation of risk depends on many factors related to physical and social vulnerabilities. This minisymposium is open to contributions from different disciplines, as the mitigation of urban disaster risks  will only be possible through the combined expertise of people from different academic backgrounds and through the collective efforts of multiple components of civil society. We invite studies that focus on, but are not limited to,  megacity growth dynamics, urban multi hazard models and multi-risk models concerning physical and social elements at risk.

This MS is devoted to the presentation of advances in engineering software for uncertainty quantification. It addresses both academic as well as commercial software advances covering applied science and engineering problems with emphasis in UQ as well as optimization under uncertainties including multiscale analysis and design as well model validation and verification.