The increasing frequency and intensity of heatwaves raises questions about the thermal vulnerability of buildings and, in particular, on how to assess their resilience to extreme heat. In this context, thermal fragility curves, which describe the probability of achieving or exceeding specific temperature thresholds for a building, serve as an effective measure to define the thermal vulnerability of existing buildings and identify tailored retrofit strategies. This study focuses on deriving thermal fragility curves for a case study: a 6-storey residential building constructed in the 1980s with a reinforced concrete structure and masonry infill walls. Dynamic thermal modeling and simulation were conducted over a one-year period using synthetic weather files generated to account for future heatwaves. The simulation results provide useful relationships in particular between: outdoor temperature and indoor Standard Effective Temperature (SET); and between outdoor daily maximum temperature and indoor SET. These relationships were finally analyzed to create and compare fragility curves using maximum likelihood fitting and the so-called Cloud methodology.

The construction industry, a major economic driver, is also a significant environmental polluter. Prefabrication emerges as a sustainable alternative due to its reduced resource consumption, waste generation, and energy use. This study proposes a MIVES-based model to assess the sustainability of precast concrete buildings compared to traditional concrete, considering environmental, economic, and social factors. A five-story commercial building in Reggio Calabria, Italy, was used as a case study. Two construction methods were compared: traditional cast-in-place reinforced concrete and a low-damage precast concrete alternative. Criteria and indicators were defined for each sustainability pillar, weighting them based on importance. Value functions converted indicator values into comparable scores. By combining these scores, a final sustainability index was calculated for each building. Precast concrete showed potential benefits in construction time, reduced emissions, and less construction disturbance. A sensitivity analysis confirmed the results. While this study highlights the potential advantages of precast construction over traditional methods, it is crucial to acknowledge the context-specific nature of the findings. The model's applicability is limited by factors such as building materials, structural conditions, and regional regulations. However, its adaptable framework can be tailored to evaluate diverse construction methods in different settings. By carefully adjusting parameters and functions, the model can offer valuable insights into the relative sustainability of various construction approaches.

Unitized curtain walls are widely adopted in contemporary architecture for their lightweight construction, aesthetic qualities, ease of installation and high operational performance. They are particularly used in high-rise buildings, where glazed facades are designed to meet a broad range of performance criteria. Well-designed systems tend to perform satisfactorily in normal service conditions, but are more problematic in extreme events. In fact, post-earthquake surveys in seismic-prone regions reveal functionality losses and moderate-to-severe damage to glazed facades, with significant financial, social and environmental consequences. Despite studies on the seismic behaviour of unitized curtain walls, research in this field remains limited. In particular, experimental studies to date rarely assess both serviceability and ultimate limit states, fail to fully characterize the sequence of damage states until collapse and overlook the influence of design choices on the façade performance. To address these gaps, an extensive experimental campaign on full-scale unitized curtain walls was conducted to investigate the seismic behaviour of façade units, including variations in geometry, joint aspect ratios and type (dry-glazed or wet-glazed), frame detailing. The experiments involved quasi-static and dynamic loading, considering in-plane, out-of-plane and vertical movements. Air infiltration, water leakage and wind resistance tests were conducted before and after low-intensity shaking to assess the post-earthquake façade serviceability. Analysis of experimental data highlighted the significant influence of silicone joints on glass rotations and the structural strength hierarchy. Fragility curves were derived from damage observations, which revealed weather-tightness loss at a 0.71% drift ratio and silicone failure in specimens with low-displacement capacity frames.

The built environment is vulnerable to climate-induced extreme events and natural disasters, which are repeatedly exposing communities to severe consequences and market disruptions. In response, the construction industry is developing resilient technologies for buildings, but the proposed solutions are often not cost-effective, rarely eco-friendly and typically fail to address multiple hazards present in many locations. These shortcomings stem from the absence of a clearly defined framework for quantifying holistic multi-hazard resilience. As a result, investment decisions are ill-informed and technical solutions are sub-optimal. This paper redresses this issue by proposing quantitative indicators and introducing the Resilience Readiness Levels to assess the resilience of buildings, considering multi-domain factors (physical, social, economic, environmental) in single or multi-hazard contexts (heat, seismic, wind, flood). The proposed resilience indices and calculation methods are based on a diverse set of scientific literature and real-world practices, and are demonstrated on Dutch and Italian urban blocks with different local hazards and building layouts. The results show that the multi-domain resilience approach can support informed early-stage building design and retrofit decision-making for single hazards, while aiding prioritization and intervention planning for improving building disaster preparedness in multi-hazard scenarios.

Creating safer and more resilient building facades has become a primary concern in contemporary design, particularly in earthquake-prone regions, where there is a potentially high impact on financial, social and environmental losses. Glazed curtain wall systems are widely used in modern architecture. Yet, despite decades of research efforts aimed at enhancing the understanding of their seismic behaviour, it is not clear how design choices affect the response of glazed facades. This is crucial given the wide range of glass, framing and joint variations that are at our disposal. With a focus on unitized curtain walls, this paper provides insights into the influence of design variables on façade seismic response by means of an extensive experimental campaign and an associated parametric study to test alternative designs under both quasi-static and dynamic loading conditions. The variables considered included variations in unit dimensions, glass and joint aspect ratios, joint and framing detailing, and support conditions. This research delves into a statistical analysis of the experimental results, in order to define parameters such as glass and façade unit rotations, frame elongations and distortions, utilization factors at different intensity levels. The results provide insights that guide façade design decisions for achieving desired seismic performance levels.

The growing concern over environmental impact and the significant improvement in the quality of engineered wood products have led to the rapid growth of the timber building industry in the last decades. Although traditional, yet recent, mass timber structural systems, such as cross-laminated timber walls, can provide satisfactory seismic performance during earthquakes in terms of life-safety, the crucial need for more resilient timber buildings has prompted the development of low-damage high-performance self-centring and dissipative solutions based on unbonded post-tensioned hybrid connections, referred to as Pres-Lam technology. The flexibility of design and construction speed, combined with the enhanced seismic performance, create a unique potential towards an earthquake-proof sustainable building system. Despite the growing popularity of the technology, a comprehensive framework for the fragility analysis, to be used in risk and loss modelling applications, has not yet been developed for both component and building levels.

In recent years, devastating earthquakes and climate-induced events have raised societal awareness of the urgent need to enhance resilience against extreme hazards. This becomes crucial when dealing with existing buildings. Many of these structures were built before the enforcement of modern seismic codes and energy regulations. Consequently, existing buildings are exhibiting a lack of resilience not only during earthquakes but also in case of extreme climatic conditions. Moreover, the energy inefficiency of the building stock should not be viewed solely as a problem related to its thermal vulnerability. It also requires an unprecedented effort to meet the goals outlined in the European Green Deal, specifically targeting energy savings and decarbonization by 2030 and 2050, respectively, to increase environmental sustainability. This work explores the feasibility of employing external low-damage exoskeletons consisting of rocking-dissipative structural connections for seismic strengthening. The implementation of exoskeletons is nowadays crucial, given the possibility of carrying out the intervention from the outside with limited disruption for occupants. Moreover, the exoskeleton serves as a support for a “double-skin” facade system offering opportunities to enhance the envelope energy performance, thereby enabling an integrated (i.e., seismic and energetic) rehabilitation. This paper discusses the advantages of using external exoskeletons compared to more traditional strategies (e.g., seismic local interventions combined with thermal coatings) by a case study application. The overall performance of as-built and retrofitted configurations is assessed through seismic and energy dynamic analyses as well as integrated loss modeling for resilience evaluations. The findings provide evidence of the efficiency of the proposed strategy and its potential.

Façade engineering is facing an era of extraordinary challenge to meet the surge in demand for buildings that are environmentally sustainable and enhance occupant wellbeing. Facades, also known as building envelopes, play a major role in the resource-efficiency of buildings and the quality of its indoor environment. Consequently, the development of effective design approaches is crucial for generating appropriate façade solutions. Façade design is complex and multi-disciplinary involving several and oftentimes conflicting performance criteria. Systematic and holistic design procedures are, therefore, required to achieve optimal trade-offs. Over the last decades, researchers in this field have used computational tools and power to address this challenging problem within the context of multi-criteria design approaches. This paper reviews the existing research in this field, and presents the state-of-the-art review from simple to advanced decision-making procedures currently used at the early design stages, where decisions have a disproportionally large impact on the façade performance. The paper provides a complete description of the design variables and objectives typically involved. Alternative multi-criteria design methodologies regarding discrete decisions and automated optimization are reviewed, each with salient pros/cons, and overall conclusions are drawn. Finally, the paper discusses ongoing trends and research needs, namely, the development of uncertainty-based procedures to enable more informed decision-making; the inclusion of structural/seismic safety considerations in the design process to achieve higher socio-economic benefits; the integration of smart building information modeling and processing technologies to facilitate smarter design decisions; and the adoption of integrated design approaches to promote climate-adaptive solutions that enhance resilience.

Facades play a pivotal role in the performance of a building, serving various environmental, structural and operational functions. As climate-induced extreme events become more frequent, developing resilient facades is becoming crucial. Although facades can contribute significantly to the total post-disruption losses, their resilience is not sufficiently addressed in current design approaches. In response to this research gap, this study proposes a multi-criteria decision-making methodology to select optimal facade designs using resilience criteria: resilience loss and economic loss. The framework addresses the complexity of facade design, considering multiple hazards such as earthquakes and heatwaves. For seismic hazard, the facade’s resilience is defined as its ability to mitigate damage. In the case of heat hazard, resilience is assessed based on the ability to keep indoor conditions within a comfortable thermal range. To demonstrate the applicability of the proposed methodology, a case study of an 18-story office building in Izmir (Turkey) is used to compare alternative facade packages. These packages identify the facade design cases, each coupled with a dataset of seismic and thermal fragility curves. Numerical simulations are conducted to derive seismic and thermal resilience curves for each facade package, along with resilience criteria. These criteria are embedded into a practical decision-making process to enable the selection of the optimal design case based on project specifications.

With the growing exposure of urban areas in seismic countries as Romania, in terms of buildings and population, it is of paramount importance to characterize at best both the built environment and the near surface. At urban and building scale level, the MULTICARE project will improve the existing methodologies and deliver technical and scientific knowledge for multi-hazard early warning monitoring and rapid response in multiple case-study areas across Europe. Our analysis will focus on two Romanian demonstrators: Tecuci, which serves as a digital demonstrator for multi-risk assessment and development of a decision support system, and Bucharest, which is based on a physical demonstrator, through retrofitting an existing residential building. The first step consists of the baseline characterization of the two demonstrators and data acquisition (earthquake and noise measurements) in free-field and buildings. In order to create a digital twin of the selected buildings, remote sensing equipment was used (ground-based laser scanning, UAVbased photogrammetry, UAV-based LiDAR). The installation setup for seismic monitoring and the near-surface measurements will be presented, together with some preliminary results on the monitoring and decision-support framework. The integration of early warning system capabilities and real-time building monitoring is a key aspect. The results contribute to better understanding the intervention solution, quantify the improvements of the retrofit work, calibrate the digital simulations on seismic risk scenarios and could be used operationally as a baseline for informed and rapid decision-making.

Lessons from recent earthquakes have provided a tough reality check of the traditional seismic design approach and technologies, highlighting the urgent need for a paradigm shift of performance-based design criteria and objectives toward low-damage design philosophy and technologies for the whole building system. Modern society is asking for “earthquake proof” resilient buildings that are able to withstand seismic events without compromising their functionality. The EU-funded SERA (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe Project) project discussed in this paper provided the opportunity to develop and validate within the European context an integrated seismic low-damage prototype, including main structure and non-structural elements, for the next generation of high-performance buildings. This paper presents an overview of the research, involving three-dimensional shake table tests of a two-storey 1:2 scaled timber-concrete post-tensioned dissipative low-damage structure “dressed” by earthquake-resistant gypsum/masonry partitions and glass/concrete facades. Specimen details, construction and assembly phases, test setup, and experimental results are discussed. After many cycles of input motions at increasing levels of seismic intensity (higher than Collapse Prevention Limit State), the integrated building system exhibited a very high seismic performance. The experimental campaign carried out at the National Laboratory of Civil Engineering in Lisbon confirmed the unique potential of low-damage technologies and the opportunity for their widespread implementation into design practice.

Different low-damage technologies have recently been developed to meet society's growing expectations for earthquake-proof buildings. Among others, the PRESSS (PREcast Seismic Structural System) technology has proved its capability to withstand earthquakes with minimal damage, effectively mitigating socio-economic losses. However, applying loss assessment methodologies can pose challenges due to the lack of data regarding fragility functions for low-damage structural components. This paper aims to propose a method for computing numerical fragility curves for rocking dissipative structural components. To achieve this, archetypes of precast concrete structures were analyzed to develop fragility models for this technology.

This article presents a numerical study on the influence of the anchorage shear hysteresis on the seismic response of nonstructural components (NSC) connected to multi-storey reinforced concrete (RC) buildings, and of the anchorage itself. To cover a variety of different types of shear hysteresis shapes, this contribution considered the experimental results obtained for five types of post-installed anchors. The results were used for calibrating the hysteresis model of the anchorage connecting an ideal NSC with rigid fixture and a 12-storey RC building host-structure. Using a suit of 40 earthquake records and assuming a single NSC at each storey level anchored by a single fastener, a series of non-linear dynamic analyses of the structure-fastener-nonstructural system was carried out. The results showed significant differences in terms of maximum acceleration and force of the NSC and anchorage, respectively, depending on the type of anchor. These seismic demands were sometimes larger than those required by the reviewed code provisions for rigid NSC, but also for the most restrictive code-case for flexible NSC. The results presented different amounts of scatter, mostly related to the size of the annular gap and of the loading stiffness of the anchorage. It is shown that the maximum force achieved by the anchorage is directly related to the peak relative velocity of the NSC within the gap region. It was concluded that the shape of the shear hysteresis of the anchorage highly influences the response of the NSC and the anchor itself and should not be neglected in practice.

Recent natural disasters and climate change-induced extremes emphasize the urgent need to enhance the overall resilience of society by addressing the various hazards that buildings may face. Current design approaches recognize the need for integrated risk assessments, but studies primarily focus on existing buildings and single hazards, neglecting the impact of multiple hazards and resilience quantifications. However, it is crucial to consider multi-hazard scenarios and quantify economic, environmental, and resilience losses to pursue effective solutions from the early-stage design of both new buildings and retrofitting interventions. This paper presents a practical multi-criteria approach to support design decisions for enhanced safety, sustainability, and resilience of buildings against earthquakes and heatwaves. The proposed approach is applied to a commercial building with various seismic-resistant and energy-efficient facades. Non-linear seismic assessments are conducted to predict the potential impact concerning repair costs, carbon emissions, and the resilience loss at the design-level earthquake. Additionally, a whole life-cycle analysis and dynamic energy simulations are performed to calculate the financial and carbon losses resulting from power consumption and the ability of the building to maintain energy efficiency under extreme heat. Finally, the study employs a multi-matrix decision-making approach based on integrated economic, environmental, and resilience losses to guide the design selection. The results demonstrate that earthquake-resistant facades can significantly reduce financial losses by over 50%, with seismic resilience playing a crucial role in the final decision. This approach facilitates more effective investment decisions for building projects, enabling the quantification of the effectiveness of integrated strategies in reducing overall potential losses.

The severe socio-economic impact of recent earthquakes has represented a tough reality check, further confirming the mismatch between society expectations and reality of seismic performance of modern buildings. Life-safety code-compliant design criteria are not enough when dealing with new structures. To raise the bar in terms of structural safety and overall performance objectives, the renewed challenge is defining high-performance buildings able to sustain a design-level earthquake with minimum disruption of business and limited economic losses. To achieve this goal, alternative strategies might be adopted: (a) implementing more advanced design methodologies, (b) increasing the seismic design level, (c) adopting low-damage earthquake-resistant technologies. However, the common perception is that these strategies would lead to unaffordable costs. To support decision-makers, the paper develops a comprehensive parametric study to compare the cost–benefit of reinforced concrete multi-storey buildings designed for increasing levels of seismic intensities (representing a higher seismicity zone or Importance Class) and according to alternative design approaches (Force-based vs. Displacement-based) and technologies (traditional vs. low-damage). Analytical/numerical investigations are carried out to determine the building performance, and loss assessment analyses are performed to compute the Expected Annual Losses of all the parametric configurations. Results, further elaborated through a machine-learning technique, highlight the convenience of implementing more advanced design methodologies, such as a displacement-based approach allowing for a better control of the building response, and the remarkable benefits of applying low-damage technologies, leading to a very high performance and significantly reduced economic losses (> 50%) for a small increase (< 5–10%) of the initial investment cost.

In the last decades, recent earthquakes have further highlighted the high vulnerability of non-structural components. Post-earthquake damage due to building envelope, equipment and building contents can lead to substantial economic losses in terms of repair costs and daily activity interruption (downtime). Moreover, non-structural damage can represent a life-safety threat for both occupants and pedestrians. These considerations confirm the crucial need for developing low-damage systems for either structural or non-structural elements. This paper aims to assess the seismic performance of glazed facade systems, widely adopted in modern buildings, focusing on point fixed glass facade systems (PFGFSs), also referred to as “spider glazing”. In this work, a numerical investigation is developed to study the seismic performance of such systems at both local-connection level through a 3D FEM in ABAQUS as well as at global system level through a simplified lumped plasticity model in SAP 2000 to assess the overall in-plane capacity of the facade. Based on the local connection and global facade system behavior, a novel low-damage connection system is herein proposed, and a parametric study is carried out on the key parameters influencing the facade capacity. The benefits of implementing low-damage connection details are highlighted by an increase of the in-plane capacity of the facade system when compared to a traditional solution. To further investigate the potential of the proposed low-damage details in preserving the integrity of the facade system itself, non-linear time history analyses have been carried out on a case-study building equipped with the innovative PFGFSs.

Recent earthquakes have confirmed the vulnerability of our built environment, resulting in significant socio-economic losses, market disruptions, and environmental damage. Additionally, climate change is causing more frequent and severe weather-related events such as heat waves, which are impacting the construction sector and the health and well-being of building occupants. This emphasizes the pressing need to increase society's overall resilience by focusing on the various hazards that buildings may encounter throughout their lifespan. Although the need for a multi-risk analysis has been recognized in current performance-based design approaches, existing studies mostly focus on single hazards thereby neglecting the impact assessment of multiple hazards on the building performance.

This paper explores the economic and social losses of buildings due to earthquakes and heat waves. The study focuses on a high-rise building consisting of a reinforced concrete structure and masonry/cladding facades, and designed for two different locations in Europe. By means of a numerical model, time-history non-linear analyses are carried out to estimate the probable maximum losses in terms of repair costs and injuries/fatalities. In addition to earthquake scenarios, the study conducts dynamic energy simulations and comfort analyses that consider local climate scenarios and extreme heat events. The energy analysis calculates the economic losses caused by weather-related power consumption while the impact on occupants is assessed in terms of discomfort hours. Results from the seismic and energy simulations are finally compared to quantify and discuss the impact of the two different extreme hazards on the building performance and their potential consequences.

Structural safety and environmental sustainability are major factors in investment decisions for building systems, but are rarely considered simultaneously. Recent research efforts have redressed this by developing assessment methodologies and technical solutions for integrated energy efficiency and seismic performance. These studies are typically limited to existing buildings and retrofit interventions at global building scale, whereas an effective framework could and should be part of the design process of either new or existing buildings at both building and component scales. This paper proposes a probabilistic-based assessment framework to assess the building performance in terms of integrated economic losses and support the selection of resilience-enhanced solutions. The proposed methodology is validated through its application to reinforced concrete case-study buildings consisting of traditional vs low-damage earthquake-resistant technologies coupled with energy efficiency strategies. Seismic and energy risk assessment analyses are performed accounting for both modelling uncertainties and earthquake/weather variability. Probabilistic distributions of the integrated economic losses are finally derived to compare the design solutions in terms of risk and reliability. The research outcomes demonstrate the effectiveness of the probabilistic approach for decision-making in building projects. Specifically, it is found that the economic losses can be highly underestimated (greater than40 %) in the single domains (energy or seismic); greater savings and return on investment can be achieved when the seismic safety is involved in the design process; probabilistic distributions and reliability/risk values can represent an effective tool to assess and compare design solutions.

High-rise buildings have large impact on the community and a significant economic value, considering the resources involved from the design through construction and use. Due to the increasing demand for renewable construction materials, the use of mixed timber-concrete solutions for high-rise structures is attracting more interest: concrete provides adequate stiffness, while timber reduces the embodied carbon of the building, including reductions in construction and demolition waste and improved recyclability. Nevertheless, in earthquake-prone countries, advanced technologies should be used to mitigate the seismic risk of high-rise buildings, considering that slight-to-moderate level of damage can produce substantial economic losses and significant environmental impact. This paper investigates the application of timber-concrete post-tensioned dissipative connections for high-rise buildings in seismic zones. These low-damage connections are able to reduce the post-earthquake residual drift and minimize the damage, thereby reducing direct and indirect losses. Furthermore, dry jointed connections allows for a flexible design approach and advantages in the construction phases. This approach is investigated through two designed case studies: a traditional concrete monolithic (cast-in-situ) building vs. a low-damage timber-concrete solution. Nonlinear dynamic analyses are performed to compare the structural/seismic responses of the case studies. A life-cycle analysis of the two buildings is developed to assess the environmental footprint, also accounting for the probable maximum losses associated with seismic damage. Results demonstrate the great efficacy of the low-damage technology for high-rise buildings: both the post-earthquake economic losses and the environmental impact are reduced by more than 40% when compared to the traditional building system.

Nonstructural components typically are not designed for seismic loads, yet their behavior can affect the post-earthquake building functionality significantly. Nonstructural damage occurs at low to moderate seismic intensities, heavily contributing to downtime and overall financial loss. Moreover, the failure of these elements can represent a potential life-safety threat for occupants and pedestrians. Due to increased awareness of these issues, in recent decades substantial research efforts have been dedicated to the study of nonstructural seismic behavior. Focusing on architectural elements (facades, partitions, and ceilings), this paper provides a state-of-the-art review of fragility functions. Seismic damage states were described and literature data were collected to build fragility domains for different nonstructural archetypes. Furthermore, references to innovative low-damage technologies are provided, and traditional (i.e., construction practice) systems were compared with low-damage components in terms of fragility. A fragility-based direct design approach is suggested based on the state-of-the-art review: nonstructural details could be designed, manufactured, or selected specifically to target desired tailored fragility curves representing targeted (multi)performance levels.