As climate-induced hazards increase rapidly, the built environment's limited preparedness highlights the urgent need to enhance resilience. Although risk assessment frameworks inform resilient design decisions for many hazards, heat stress at the building scale are often addressed using simplified code-based approaches. Emerging heat fragility models provide a basis for risk quantification; however, a unified heat risk framework that estimates multi-domain consequences (social, economic, environmental) accounting for multi-factor uncertainties (climate, building, occupant) is still lacking. To address this gap, this paper proposes a probabilistic method grounded in performance-based engineering principles. The approach integrates hazard analysis, building performance evaluation, fragility modeling and loss estimation, and employs a Monte Carlo framework to propagate uncertainty across all stages. Its step-by-step implementation is demonstrated on a multi-story building under varying design conditions and climate scenarios, proving the framework's ability to quantify probable maximum losses and incorporate them into risk matrices. The case study results show energy demand and carbon costs increasing by around 13% under high-warming scenarios, with heat-related mortality nearly tripling in naturally ventilated conditions, enabling building-level comparison across performance thresholds and hazard severities. Probabilistic loss functions translate these impacts into expected annual losses, further highlighting the importance of passive survivability, as cost and carbon metrics are projected to increase by 50% while mortality risk rises sharply for the analyzed building. These annualized losses can inform building-level design decisions and multi-hazard resilience planning, as the proposed approach aligns with probabilistic models and risk metrics used in catastrophe modeling to compare natural and climate hazards.

The authors wish to replace the flood hazard map in Fig. 11a with an updated map for the Acerra region. The legend has been revised to display only the minimum and maximum flood depth values.(Figure presented) Fig. 11. (a) Flood hazard map for the Acerra region (Pluvial flooding - RCP 8.5 for year 2050, 50th Percentile - 1000 years return period) overlayed on the case study buildings (highlighted in orange).

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 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 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.

The built environment is increasingly exposed to more frequent and intense climate-related extreme events. Although numerous frameworks exist to assess the impacts of extreme events - usually measured in terms of deaths, dollars and downtime - several authors have shown that indirect losses, often driven by the recovery phase rather than the response one, can represent most of community losses. Delays in initiating repairs significantly increase indirect losses but are often overlooked in frameworks focused only on immediate response. While recent resilience-based approaches aim to include both response and recovery, their indices often lack clear links to measurable physical outcomes. The definition of a clear, relatable, scalar index could better inform stakeholders and decision-makers about potential risks and guide them in planning mitigation strategies. This paper proposes a novel framework for quantifying socio-economic (direct and indirect) losses by considering both the response and recovery phases of extreme events. Building on resilience principles and functionality-time curves, this framework offers a comprehensive yet practical method for quantifying indirect losses. The approach is validated through a multistory building subject to earthquake and flood hazards, by employing a component-based probabilistic loss modelling approach. The framework was able to provide an estimation of indirect losses due to business interruption showing how indirect losses can match or even exceed the direct economic losses due to damage repairs.

Building energy prediction models expedite performance assessment and assist in decision making, from early-stage design to retrofit planning at single- or multi-building scales. However, the number of parameters involved in the energy performance evaluation often impede the prediction process requiring the assimilation of high-dimensional, uncertain input. This is compounded further at multi-building scale e.g. urban energy modelling, due to the increased complexity of evaluating diverse building geometries. While single-building sensitivity and uncertainty analysis is well-established for identifying the most influential input parameters and evaluate the uncertainty effects on energy demand, these are hard to generalize at multi-building scale which remains relatively unexplored. The present study advances existing research by applying a variance-based sensitivity analysis to assess the impact of varying (i) building façade layout, (ii) envelope thermal properties, (iii) envelope air tightness and (iv) building occupancy. The analysis is conducted for multiple buildings under two future climate variations, while also considering the degradation of material thermal properties. The latter is derived from known deterioration models for single-building uncertainty propagation, relying on experimental and simulated data. The approach is applied to a temperate oceanic climate with particular focus on the Dutch building stock, including a sample of buildings with diverse geometric characteristics in Rotterdam. First-order Sobol indices are computed to evaluate the impact with respect to the heating, cooling and total energy demand. Our findings indicate that infiltration is the most influential factor for heating energy demand, whereas cooling is mostly affected by the envelope thermal properties and, particularly, window solar heat gain coefficient. Common patterns regarding the impact of insulation across different envelope components can be identified among buildings with similar orientation and compactness ratio indicating the importance of considering these geometric properties in retrofit decision-making workflows.

Current multi-hazard risk approaches in seismic engineering primarily focus on structural performance under hazards such as earthquakes, floods, and wind. Despite the distinct risk due to their direct impact on human health, heatwaves receive limited consideration. This unbalanced and fragmented approach is particularly noticeable in facade retrofit design, which has a significant influence on both structural vulnerability during earthquakes and indoor thermal conditions during heatwaves. In this case, integrating seismic and heat risk considerations would help balance performance trade-offs across both domains and assist designers in the selection and combination of technologies that are effective under seismic and heatwave conditions. This study therefore proposes a simulation-based multi-objective methodology for facade retrofit decision making. The suggested approach is demonstrated through a case study: a reinforced concrete building retrofitted using a timber rocking-dissipative external exoskeleton and precast concrete sandwich facade panels. Key facade design parameters-component capacity and dimensioning-were varied to generate a multivariate response for both seismic and thermal performance. The simulation results revealed two challenges for optimization: a limited sample size and nonlinear relationships between design inputs and performance outcomes. To address both, a multivariate regression was applied within segmented performance ranges, defined by breakpoints where the relationship between parameters and performance shifted. The resulting segmented multivariate model enabled the identification of optimal technology combinations within specific performance ranges and the generation of multiple Pareto fronts. This broadened the viable solution space and better supported project-specific trade-off decisions.

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.

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.

When dealing with seismic risk assessment of existing buildings, the technical complexity arising from limited building knowledge often represents a primary obstacle, potentially leading to high levels of uncertainty. This issue is critically emphasised in large-scale applications, where a statistical characterization of the building stock is typically assumed based on a few building data. Yet, recent research in the literature has pointed out that various types of information on the structure, such as structural details and material mechanical properties, can have significant impacts on the seismic performance assessment. This would suggest that the diagnosis phase could be conducted through an incremental procedure enabling the gradual acquisition of significant information on the seismic performance of the structure, even in scenarios where data collection is limited. Moreover, when coupled with an ad-hoc data collection form, a knowledge-based seismic risk assessment approach could serve as an important step toward achieving a building-to-building characterization of the national building stock. To this end, standardised, adaptive and updatable methodologies and tools for knowledge-based seismic risk assessment of buildings are essential. As part of a wider ReLUIS research project, this paper discusses the ongoing developments in the definition and validation of a multi-knowledge seismic assessment methodology based on the SLaMA (Simple Lateral Mechanism Analysis) method. Particular focus is given to an application of the SLaMA-based procedure to an existing reinforced concrete school located in a high seismic hazard zone in Italy. To simulate a realistic “incremental” diagnosis phase, two different Research Units (RUs) are involved in the investigation: RU-1 and RU-2. Operatively, RU-1, owning relevant building data, progressively shares information with RU-2. Subsequently, RU-2 conducts a knowledge-based seismic risk assessment for each data collection scenario. The results are finally returned to RU-1, which analyses and compares them with the existing documentation. The preliminary results of the ongoing investigation are herein presented and discussed. The SLaMA-based procedure enables the identification of the expected range/domain of capacity curves and seismic risk classes from the first diagnosis phases. This information can support the decision-making in localised in-situ inspections and/or possible retrofitting solutions.

The European building stock, mostly built post-World War II with no regard to seismic design and energy efficiency principles, is facing significant safety and sustainability challenges. The seismic vulnerability of existing buildings has been further confirmed by recent earthquake disasters, such as L’Aquila 2009, Centre Italy 2016, Turkey & Syria 2023, whereas the energy inefficiency is underscored by high energy consumption rates. An unprecedented effort is therefore required to increase seismic safety while achieving energy savings and decarbonization targets to meet the ambitious goals of the European Green Deal. Although several technical solutions are available in separate engineering domains, it is essential to adopt integrated renovation strategies (i.e., structural and energy efficient), especially when dealing with buildings located in zones with moderate-to-high seismicity. This work explores the application of exoskeleton-type solutions for integrated building renovation. Specifically, external load bearing systems consisting of low-damage timber-based structural members (the so-called Pres-Lam technology), that upgrade the seismic performance by reinforcing existing building. Such a solution is particularly attractive because the renovation interventions are entirely executed from outside the building, thereby reducing occupant disruption and avoiding relocation of inhabitants. This aspect is crucial in motivating owners to choose a combined low-invasive renovation that goes beyond simple energy retrofitting and improves the resilience of the energy upgrades, which on their own could become ineffective after future earthquakes. The proposed exoskeleton system has a dual role of operating as the support for a high-multi-performance “double-skin” facade system that improves the seismic resilience of the existing building and enhances its energy efficiency, thereby proving a holistic renovation. The main goal of this work is to prove the effectiveness of the proposed integrated renovation strategy through an illustrative case study. The overall performance of both the as built/retrofitted structures is assessed by means of seismic and energy analyses. Building on such results, a loss assessment procedure is implemented to quantify the overall economic and environmental impact in the building lifespan. It is found that the proposed strategy enhances the holistic performance of the building with a 54% reduction of the economic losses.

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.

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.

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.

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.

Unitized curtain walls play an integral role in contemporary architectural designs, offering advantages such as lightweight construction, high quality control and ease of installation. However, recent post-earthquake surveys have revealed their vulnerability to damage, raising concerns about potential hazards in post-earthquake scenarios. Even slight-to-moderate damage can lead to loss of functionality and economic losses, arising from breaches in the air/water tightness of the building envelope and costly repairs/replacement. Furthermore, as the damage progresses from moderate to severe, it poses a life-threatening risk to occupants and pedestrians due to falling glass or debris from the damaged façade. Among the different types of unitized curtain walls, structural silicone glazing emerges as a resilient assembly system with the potential to enhance the seismic performance of the façade. Nevertheless, despite initial studies on the seismic behaviour of the silicone bonding sealant, research in this field remains limited. Typically, experimental investigations overlook the analysis of the complete sequence of damage states and the ultimate resistance of the various components within the silicone-bonded façade. As part of a broader EU-funded research project, this paper presents the key findings derived from an experimental campaign on structural silicone glazed facades conducted at the Permasteelisa Group laboratory. The overall research aimed to gather information on the post-earthquake functionality and the failure modes of alternative façade designs. The hierarchy of damage mechanisms that occur during an earthquake was established by testing full scale façade prototypes with different pane and silicone joint dimensions, frame displacement capacity and loading mode. The testing procedure involved a series of in-plane displacement-controlled crescendo tests, time histories and monotonic testing, gradually increasing the intensity levels to evaluate the progressive damage states within the façade system. The paper provides the main outcomes derived from both damage observations and data post-processing, including the assessment of utilization factors and fragility curves for the façade components. These results offer valuable insights into the seismic behaviour of structural silicone glazed facades, thereby supporting the future development of design guidelines and practices for more resilient facade systems.

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.

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.