The course aims to define strategies related to building resilience against climate change, focusing on the building envelopes resistance to extreme wind events. In particular, building and environmental components, namely potential flying debris, are considered as the vulnerable elements subjected by strong wind events. Therefore, the goal is to identify risk mitigation actions, by reducing building and environmental components vulnerability and to improve the resiliency of the built environment to extreme wind phenomena, as well as to prevent major losses to the properties affected and to guarantee higher safety to the people indoor and outdoor.

SUBJECT AND PROGRAM OF THE COURSE

Climate change is one of the issues of our time. The key climate-related hazards, such as windstorms, forest fires, heavy rain and floods, etc., lead to the growing necessity for buildings to be resilient to extreme and unpredictable weather conditions. The increased frequency, intensity and impacts of extreme events call also for buildings designed for protection against physical damages and failures. Moreover, building envelope resilience requires smart implementation of technology, material knowledge and engineering processes. Resilient buildings need to face many challenges in many combinations (hurricanes and high wind resistance, wildfire events, etc.) but today their design hardly includes these items. Furthermore, the most commonly used climate data for buildings design and studies are no longer sufficient, and traditional climate variables, fundamental inputs to most engineering disciplines, need to be seriously reconsidered.

Governing bodies in areas prone to extreme weather events (i.e.: Florida, Honk Kong, Japan, Australia) already implemented several measures to mitigate the effects on the built environment, with special attention to wind events. Studies and field observations have been conducted on the consequences of major past and recent hurricanes, typhoons and tornadoes on the built environment and human safety (FEMA 1993; CTS 2017). Such measures have one major goal: preventing the damages to people and properties due to flying debris. Such objective is sought by adopting two sets of measures: on one side, reducing the likelihood of the flying debris phenomenon, by improving the resistance of man-made elements to wind; on the other side, mitigating the consequences of flying debris, by setting design guidelines and testing methodologies to ensure the resistance of the building envelope to the impact of flying debris. These measures apply to all buildings in areas prone to severe winds: easier target performances are requested for common buildings, while classified infrastructures (hospitals, emergency services, schools, etc.) are requested to meet very demanding requirements, especially for their envelopes.

Currently, there are no requirements related to the consequences of wind-borne flying debris in Europe, nor in Italy, because in the past such events were considered so exceptional to not represent a threat. However, it is a matter of fact that several European countries experienced an increased number of extratropical cyclones and tornadoes in the very last years (Trabucco et al. 2018) including multiple so-called Medicanes (cyclones formed in the Mediterranean Sea). During wind events, threats are due to the detaching and flying of materials and pieces from buildings and other man-made structures: roof tiles, façade elements, antennas, etc. are dragged away becoming flying debris that endanger people and properties, hitting surrounding buildings at high speed (ASCE 2014; Butler and Kareem 2012). Therefore, wind can cause direct damages to the envelope of buildings (detaching of elements from the source ones) and indirect damages, caused by flying debris (impact of flying debris on a target building).

Wind has been investigated extensively to prevent the failure of major building elements. Accordingly, codes and standards have been developed since decades, but recent extreme wind events in Italy and Europe prove that our existing buildings are very vulnerable. The combination of increased wind actions, the old/historic building stock and meteorological events with different characteristics from the past (i.e.: downbursts) are the main reasons of wind-induced damages. A risk analysis based on hazard, vulnerability and damage specific for the Italian urban environment will be illustrated. In particular, building and environmental components, namely potential flying debris, are considered as the vulnerable elements subjected by strong wind events. Therefore, it will be explained how it is possible to identify risk mitigation actions, by reducing the element vulnerability or the target characteristics.

In particular, the course will focus on:

• providing a theoretical solid background on the main technologies of the modern building envelope constructions, whose complete understanding is fundamental to analyse the failure mechanisms under wind;
• providing technical and construction details of advanced building envelopes engineering, particularly dealing with the physical and geometrical interface between the envelope and other systems and parts of the building;
• identifying the built environment elements that can fail in the context of extreme wind events and providing their technological characterization in order to understand the reason of their failure. The fact that these elements are specific to the context (local building practices, age of the building stock, etc.) and differ from the elements that fail in other geographical areas will be considered;
• identifying the building elements to be reinforced to avoid their failure under extreme winds;
• advanced design strategies for the building envelopes, with detailed focus regarding their performances when subjected to extreme wind events, with a focus on specific infrastructures (hospitals, emergency services, schools, etc.);
• risk analysis and mitigation strategies to prevent wind-induced damages to buildings, and the flying debris phenomenon to occur;
• consequences of flying debris impacts on buildings, with a specific focus on their façades and developing wind-borne debris resistance building envelopes;
• strategies to mitigate environmental impacts with effective modelling tools intended to improve technological and environmental efficiency and support the above-mentioned strategies;
• regulatory framework, processes and protocols and method statement examples for testing cycles that evaluate building envelope performance in real and extreme conditions.

The course is connected with the Sustainable Development Goals n. 13 “Take urgent action to combat climate change and its impacts” and n. 11 “Make cities and human settlements inclusive, safe, resilient and sustainable” and with the Strategic Research Lines of ABC-PhD “Risks mitigation strategies for built environment” and “Innovative design for architecture, spaces and services: health, safety, inclusion, education and emergency”.

During the course, students are expected to:

• develop their base knowledge on building envelopes;
• acquire knowledge on potential flying debris, considered as the vulnerable elements subjected by strong wind events;
• identify risk mitigation actions, by reducing building and environmental components vulnerability, to improve the resiliency of the built environment to extreme wind phenomena, as well as to prevent major losses to the properties affected and to guarantee higher safety to the people indoor and outdoor.

LECTURERS

Enrico S. Mazzucchelli, Paolo Rigone, Angelo Lucchini, Martino Milardi, Dario Trabucco

The lectures, always accompanied by examples, will be combined with the assignment of a Case Study, applied to specific building contexts and building materials used in the European countries bordering the Mediterranean sea, using Italy as the main reference country (however, other countries might be chosen and defined in agreement with the students). Students will be asked to work on a Case Study and to write an essay identifying specific strategies to prevent wind-induced damages and the flying debris phenomenon to occur. The assessment will be based on presentation and discussion of the Case Study.

Day 01 - 18 Jan 2022 (9:30-13:00 / 15:00:18:30)

Introduction of the course topics. Main technologies of modern building envelopes. Technical and construction details of advanced building envelopes. Assignment of the workshop case studies.

Day 02 - 21 Jan 2022 (9:30-13:00 / 15:00:18:30)

Analysis of building and built environment elements that can fail during extreme wind events. Overview of the international best practices to prevent wind-borne debris damages. Analysis of case studies of extreme events and resulting damages. Evaluating advanced design strategies for the building envelopes, with detailed focus regarding their performances when subjected to extreme wind events, with a focus on specific buildings.

Workshop - In-depth analysis of the case study.

Day 03 - 24 Jan 2022 (9:30-13:00 / 15:00:18:30)

Study and analysis of building elements to be reinforced to avoid their failure under extreme winds. Consequences of flying debris impacts on buildings façades and strategies for wind-borne debris resistant building envelopes design.

Workshop - In-depth analysis of the case study.

Day 04 - 27 Jan 2022 (9:30-13:00 / 15:00:18:30)

Strategies for the mitigation of environmental impacts with effective modelling tools intended to improve technological and environmental efficiency and support the strategies for resilient building envelopes design. Regulatory framework, processes, protocols and method statement examples for testing cycles that evaluate building envelope performance in real and extreme simulations.

Workshop - In-depth analysis of the case study.

Day 05 - 02 Feb 2022 (9:30-13:00 / 15:00:18:30)

Final overview and conclusions on strategies and tools for advanced building envelopes design towards resilient constructions. "Question and answer" workshop on the students' case study essays.

Advances in Hurricane Engineering: Learning from Our Past.

Advances in Hurricane Engineering. Learning from Our Past. ASCE

International Workshop on Wind-Related Disasters and Mitigation Tohoku University, Sendai, Japan

Advances in Hurricane Engineering: Learning from Our Past. ASCE

Rehabend Congress, 28 September 2020, Granada (Spain)

TEMA Technologies Engineering Materials Architecture

TEMA Technologies Engineering Materials Architecture

Journal of Faade Design and Engineering

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CTBUH Research Report

L'Ufficio Tecnico n. 11-12/2017, 82-89

Council on Tall Buildings and Urban Habitat

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Journal of Faade Design and Engineering

Glass Performance Days 2017 Proceedings, Tampere, Finland, 2017, 64-69