Structural failures in building construction
The recent earthquakes in southern Turkey and northern Syria have caused extensive damage to multi-story buildings, leading to the tragic loss of life. Reports indicate that poor construction standards, including the use of low-quality concrete and relaxed regulations, may have contributed to the collapse of these structures. Unfortunately, this is not a new phenomenon, as previous earthquake events in Turkey have also revealed similar issues with construction standards.
In this article, we want to highlight the importance of proper detailing in the construction of multi-story buildings using concrete and steel. When we say detailing, we refer to the precise arrangement of steel reinforcing rods that support the concrete matrix. This process involves using the right thickness and quality of steel rods, ensuring they are not too close to each other or placed near the edge of a beam to avoid splitting or spalling and using confining stirrups to bind vertical steel bars inside a column. Detailing is particularly critical at junctions, where a column meets a horizontal concrete beam, or a column supports a slab, or where a balcony overhangs from a wall.
The computer-aided design software is now used to calculate and specify the configuration of steel rebar, and the contractor creates the skeleton of steel bars according to the architects’ precise specifications. The fresh concrete mix is then tested to ensure the right composition before being poured into the temporary shuttering, vibrated down to remove air pockets, and allowed to slowly set. Architects and structural engineers, who have spent four or five years at college and have experience with construction projects, are responsible for checking each other’s work and keeping detailed records.
Another important issue to take into account is the use of the National Code of Practice for the design of any concrete structure. The Code marks the standard that building structures must comply with. Any structure that collapses in an earthquake can be checked to see if the reinforcements and concrete comply with the National Code and thus establish the responsibility of the designer.
However, another usual problem is the misuse of concrete, which is synthesized from Portland Cement, which has caused many unnecessary and premature deaths worldwide. Cement has been transported in overloaded lorries to developing countries since the middle of the twentieth century, resulting in poor-quality construction and the use of low-grade materials. This has led to the entombment of innocent people in poorly constructed buildings, especially in earthquake-prone areas.
In conclusion, it is crucial to prioritize proper construction standards, including the use of high-quality materials and adherence to regulations, to prevent disasters caused by the misuse of concrete. Architects and structural engineers play a vital role in ensuring that multi-story buildings using concrete and steel are constructed to the highest standards, with proper detailing and quality control measures in place.
According to the United States Geological Survey (USGS), global cement production was estimated to be 4.1 billion metric tons in 2020. Cement is a key ingredient in concrete, so this figure provides a good estimate of the world’s concrete production as well. It’s worth noting that concrete production varies from year to year and is influenced by various factors such as economic conditions, population growth, and construction activity which represents almost a hundredfold rise in just 60 years.
This has resulted in a surplus of cement in various countries, leading to lower prices. Cement has brought modernity and globalization, allowing small-town builders to create impressive structures previously seen only in movies. However, this also brought new challenges, as builders lacked the knowledge and skills to work safely with cement, particularly when it came to steel reinforcing.
In developed countries, engineers with proper training and knowledge supervised concrete construction, while in developing countries, there was a significant lack of engineers. Reinforced concrete was no longer a simple formula, as detailed knowledge of materials, forces, and failure tolerance was required to ensure safety. Building failures caused by bad design, execution, reinforcing, or concrete was prevalent and caused many fatalities in earthquakes.
The schism between rich and poor countries on reinforced concrete construction has been known for many years, and it is necessary to entrust construction to architects and engineers with proper technical knowledge to prevent disasters. Untrained builders constructing buildings with concrete without the supervision of structural engineers could be compared to giving a child a loaded automatic weapon. The impact of concrete construction in lower and middle-income countries is evident in the aftermath of earthquakes, such as the İzmit earthquake in Turkey, where unlicensed concrete apartment blocks collapsed, causing thousands of fatalities.
In conclusion, there is a pressing need to seriously address how to construct buildings with concrete responsibly in earthquake-prone areas to prevent unnecessary loss of lives. The United Nations has warned that fatalities could double from the current 40,000 plus total, emphasizing the urgency of taking action.