Summary of Failure analysis of historical buildings due to climate change from June 1st 2017 engineering failure analysis.
The article talks about generally the effect of the drastic climate change on historical buildings with focus on Oravita, a city in Romania where a study whose the article was based on was carried. These buildings have been destroyed by climate factors e.g. hail, heavy rains, floods et cetera because during construction climatic change was not considered. Going forward during construction engineers should consider past and the current climatic conditions. On top of that reinforcements can be done on historical buildings so they can withstand current weather factors and to preserve heritage.
The town of Oravita is located in the south western part of Romania. The town historically was a mining town and the town’s architecture was greatly influenced by the mining specialists who emigrated to oravita from Hasburg Empire. This led to a complex and strange combination of urban and rural aspects. The buildings are mainly made of limestone or brick with a combination with wooden floors, wooden gabled roof structures and roofs covers made of ceramic tiles. The town has a temperate continental climate, with influences from the Adriatic and Mediterranean seas and Atlantic Ocean. The climate in this region is hence defined by warm periods during winter and early springs and by a high mean rainfall. High velocity wind also influences the town.
Wind is one of the climatic factors damaging these historical buildings. This happens in different forms i.e.
- High speed wind. Even though buildings are generally adapted to extreme wind speed historical building walls and roof structures are not.
- Wind driven rain. Rain is another factor. Most extreme damage on the historic surfaces are caused by freeze-thaw, snowfall, rainfall frequency and the heavy rain events more than by precipitation.
Damage can also be caused by landslides. Almost half of the city was developed on the sloping hillsides near riverbeds and are hence high landslide areas today. Landslides can be caused by reduced quality of used materials, inadequate infrastructure and heavy rainfall. The city was developed on the hilltops to protect the historic part of the town and to reduce the risk but these places are now high risk areas. The retaining walls built are not in good state of conservation and have suffered displacement. For instance due to heavy rains in 2014/2015 there was a landslide triggering the collapse of the historic structure.
Hail has also caused damages. These are a real threat as they cause severe damage to the historic surfaces e.g. roof coverings, building facades and architectural decoration. Hailstorms so far have only affected retrofitted buildings but should the frequency of hailstorms and hailstone size continue to grow then even the historic surfaces and architectural ornaments will be at risk.
Visually assessing then the most severe effects of natural hazards were caused by wind-driven rain and hail stones. To determine the effect of wind driven rain the formulae
Rwdr = αURh88 cos β where;
- α (s/m)-the exposure factor that takes the local topography and the urban characteristics into account
- U (m/s)-the reference wind speed, measured according to the meteorological standards
- Rh-the rainfall intensity
- β-the incidence angle between the wind direction and the building façade.
In conclusion, the study determined that despite historic buildings’ high resilience they are still extremely vulnerable to present and future climate change. The study establishes measures to prevent damages to historical buildings and to protect their authenticity. In addition as an engineer I would recommend further studies by other engineers, extensive studies which could include different parts of the world and study different factors that damage historical buildings. These can find what climatic changes pose the greatest risk and prioritize those in dealing with reinforcing historical buildings. Also, researchers can take into consideration other meteorological parameters that were not taken into account here for instance, temperature and other factors e.g. environmental pollution. Since there is a way to calculate and predict future expected damages then measures can be determined to prevent them. Engineers should also be made aware of climate change effects on buildings and possibly be provided with a guideline to follow in order to factor in climatic change when constructing the buildings. These could include trying to produce low carbon buildings through good building design to achieve mitigation targets for the future and good low energy designs and creating standards to be met by all buildings. Engineers should also make use of modern technology e.g. computer modeling which can help with decision making and identifying vulnerabilities.