Thunderstorms and the Impact on the Built Environment

In recent efforts to understand the influence of severe weather events on urban infrastructures, Ileana Calotescu, Xiao Li, Mekdes T. Mengistu, and Maria Pia Repetto conducted a significant study, which was published in the Journal of Wind Engineering and Industrial Aerodynamics. The study covered an 8.5 km2 survey area with over 2000 structures; most were single-storey residential buildings. The researchers uncovered wind-induced damage to low-rise buildings caused by a thunderstorm in Sânnicolau Mare, Romania.

The researchers identified 237 cases of damage directly caused by thunderstorms among the 2000 structures surveyed. This data reflects buildings’ vulnerability to the harsh and often unpredictable conditions brought about by such meteorological phenomena.

The source of the Romanian wind code is “Normativ privind calculul construcțiilor și elementelor de construcții. ​ CR1-1-4/2012 Cod de proiectare. ​ Evaluarea acțiunii vântului asupra construcțiilor” (CR1-1-4/2012 Design Code. ​ Evaluation of Wind Actions on Structures). ​ The Romanian wind code, CR1-1-4, is an adapted version of the Eurocodes, specifically EN1991-1-4. ​

With importation of building products on the rise, understanding international building codes and there relation to relevant New Zealand codes will become more important. So the team at Rommel have taken a quick look at the study conducted in Romania for wind damage buildings.

thunderstorm impact | Rommel NZ

Thunderstorms and the Built Environment

Methodology and Key Findings

The researchers employed a two-pronged approach in their study:

Full-Scale Measurement

Advanced monitoring tools were used to record real-time data during thunderstorms. The aim was to capture the immediate effects of wind speeds, pressure changes, and other relevant parameters contributing to building damage.

Post-Event Damage Survey

After the thunderstorm events, a detailed survey was carried out to assess the extent of damage inflicted on structures. This provided empirical evidence to support the measurement data.

The percentage of damage to buildings in the survey concluded that 11.85% of buildings were damaged within the 8.5 km2 survey.

Percentage of building damage = (237 / 2000 ) x 100 = 11.85%

The damage survey conducted in the study revealed several types of wind damage to the buildings, including: ​

Roof failures

The survey identified cases of roof damage, such as torn-off roof coverings, dislodged roof tiles, and partially or completely collapsed roof structures. These cases included roof failures such as roof coverings being torn off, roof tiles being dislodged, and roof structures being partially or completely collapsed. The roof failures were caused by wind-induced forces during the thunderstorm event.

Facade damage

The survey also found damage to building facades, including shattered windows, blown-off doors/gates , and damaged or destroyed wall fences with 220 of the cases reported as facade damage

Structural damage

Some buildings experienced structural damage, such as walls being cracked or leaning, and supporting columns or beams being damaged or weakened.

Windborne debris impact

The wind also caused damage by picking up and hurling debris, such as tree branches, signs, and loose objects, which resulted in damage to buildings. ​

The study focused on collecting data on wind-induced damage mechanisms and validating wind intensity estimation scales rather than providing a comprehensive analysis of each building’s damage. ​However, the findings provide an interesting analysis for considering storm-induced damage.

Analyzing Wind-Induced Roof Damage

The research documented roof damage caused by windstorms and highlighted such natural calamities’ dynamic and potentially destructive power. The team recorded a total of 17 cases of wind-induced roof damage using traditional survey methods and modern crowdsourcing techniques to gather data.

Detailed Observations and Crowdsourcing: A Dual Approach

Among the 17 documented cases of roof damage, four were directly observed by researchers on-site during in-situ investigations. These on-site observations are crucial as they allow researchers to assess damage directly, providing clear, uncontested evidence of the impact and mechanisms of wind on roofing structures. The firsthand data collected through such empirical methods forms the backbone of reliable scientific research.

The remaining 13 cases were identified through innovative crowdsourcing efforts. This method leverages the community’s power to report additional incidents, significantly expanding the scope of the survey. Crowdsourcing in this context is particularly useful for quickly gathering large amounts of data across a wider area than might be feasible for a traditional survey team alone. Additionally, it engages the public, increasing awareness about the study and possibly encouraging preventive measures in the community.

Challenges in Data Collection

However, the study also encountered limitations inherent in such research methodologies. It’s noted that there could have been additional instances of wind-induced roof damage reported by witnesses but not confirmed by the survey team. The primary reason for these unconfirmed cases was restricted access to private properties, a common obstacle in conducting comprehensive in-situ investigations.

Access to private property requires permission from owners, and without it, researchers must rely solely on reports that cannot be empirically verified. This restriction can potentially lead to underreporting in the study’s findings and affects the overall data precision. To maintain the integrity and accuracy of their data, the study excluded these unconfirmed reports from the final analysis.

Implications for Future Research and Building Codes

The mixed-method approach of direct observation complemented by crowdsourcing represents a significant advancement in environmental damage assessment. Such strategies can lead to better-informed building codes and more effective disaster preparedness and response strategies.

Addressing the challenges of accessing private properties for scientific research also calls for enhanced cooperation between researchers, local authorities, and the public. Enhancing this collaboration can ensure more comprehensive data collection and accuracy in future studies.

This innovative approach to studying wind-induced roof damage sheds light on the extent of such destruction. It opens pathways for improving research methodologies and building more resilient communities against the forces of nature.

Implications for Urban Planning and Architecture

The findings of this research are crucial for urban planners, architects, and disaster management authorities. Understanding the statistical likelihood of building damage from thunderstorms aids in developing more resilient infrastructure. Furthermore, these insights help refine building codes and standards, ensuring structures are better equipped to withstand the impacts of severe weather.

Towards a Resilient Future

The value of studies like the one conducted by Calotescu et al cannot be overstated. As climate change continues to influence weather patterns globally, the frequency and severity of thunderstorms are likely to increase. Preparing the built environment to cope with these changes is not just necessary for safeguarding property but also for protecting lives.

This research not only sheds light on the direct impacts of thunderstorms on buildings but also serves as a catalyst for encouraging further studies in this critical field of wind engineering and industrial aerodynamics.

The Rommel team is available to conduct building assessments for water ingress on facades, roofs, windows, and doors. If you have a project that requires onsite testing procedures, please contact us to discuss.

Reference

Ileana Calotescu, Xiao Li, Mekdes T. Mengistu, Maria Pia Repetto,
Thunderstorm impact on the built environment: A full-scale measurement and post-event damage survey case study, Journal of Wind Engineering and Industrial Aerodynamics, Volume 245, 2024, 105634, ISSN 0167-6105
https://doi.org/10.1016/j.jweia.2023.105634.