Set out on an eye-opening exploration of disaster mitigation in construction. Discover innovative methods revolutionising our resilience against the elements!
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19 Apr 2024
7 Min Read
Ali Moossajee (Alumni Writer)
Set out on an eye-opening exploration of disaster mitigation in construction. Discover innovative methods revolutionising our resilience against the elements!
In today's world, the threat of natural disasters looms ominously over us. Climate change has worsened their frequency and severity, posing significant risks to societies worldwide. Based on reports by the United Nations Office for Disaster Risk Reduction (UNDRR), we have estimated an approximate 80% increase in climate-related disasters over the last 40 years. This surge has led to a substantial rise in global economic losses, with the annual average increasing from around $50 billion in the 1980s to under $230 billion in recent years, as documented by the World Bank. These statistics are undeniably daunting, but amid the chaos, there is hope. Imagine a world where our buildings not only stand strong against natural disasters but also become stronger because of them. Impossible? Not quite. With innovative construction methods, we can create structures that weather the worst of 'storms' and emerge even more resilient — ultimately reducing the damage caused by natural disasters and saving lives and livelihoods.
Earthquakes, often associated with specific regions known for seismic activity, can have far-reaching effects beyond them. 'How does it affect me if I live in an earthquake-free region?' you may ask. While earthquakes may appear as a local crisis, their impact reverberates beyond those hotspots, making them a global concern. Disruptions to global supply chains, for instance, can occur when key manufacturing hubs or transportation networks are affected by earthquakes, causing ripple effects throughout the interconnected global economy. Hence, even earthquake-free regions are not immune to the indirect consequences of seismic activity.
Therefore, disaster preparedness is imperative worldwide, irrespective of seismic activity. Building resilience and implementing robust infrastructure and response systems are pertinent to safeguarding communities against these natural disasters. By recognising earthquakes as a global concern and investing in proactive countermeasures, nations can mitigate the widespread impact of seismic events.
Recent tremors in regions like Taiwan are stark reminders of the unpredictable power of the earth's movements. However, in the face of these challenges, Taiwan has met them head-on as a pioneer in implementing innovative seismic engineering solutions to mitigate their impact. One notable example is the Taipei 101 skyscraper, once the tallest building in the world. This iconic structure incorporates advanced seismic design features, including a tuned mass damper — a massive pendulum suspended near the top of the building, which oscillates in opposition to counteract the swaying motion caused by earthquakes and strong winds.
Additionally, many residential and commercial buildings in Taiwan have adopted base isolation systems, which involve the placement of flexible bearings or isolators between the building's substructure (i.e., base) and superstructure. These isolators absorb and dissipate seismic energy by acting as shock absorbers, allowing the building to move independently of the ground during an earthquake.
In the category of natural disasters, hurricanes rank as harbingers of large-scale destruction. Take Hurricane Katrina, which ravaged the Gulf Coast of the United States in 2005, leaving a trail of devastation in its wake. With winds surging up to 233 kmh, Katrina breached levees, inundated cities, and claimed thousands of lives, exposing the vulnerability of coastal communities to nature's fury. Similarly, Hurricane Maria struck Puerto Rico in 2017 with winds of 250 kmh, plunging the region into chaos. The aftermath of Maria, with its infrastructure decimated, power grids crippled, and communities shattered, underscored the urgent need for robust disaster preparedness and response strategies.
Over the years, the University of North Carolina at Chapel Hill has developed and released its Design Guidelines to ensure the quality and consistency of building and infrastructure design across the campus. These guidelines incorporate various innovative features to enhance resilience against the formidable forces of hurricanes and other coastal hazards. They recommend a reinforced concrete foundation anchored deep into the ground to withstand lateral forces from high winds and storm surges. Additionally, the guidelines suggest the use of a robust structural system comprising steel and concrete elements engineered to withstand the dynamic loads of hurricane-force winds.
Furthermore, the guidelines advise the implementation of impact-resistant windows and doors on the exterior, made from laminated glass or polycarbonate materials capable of withstanding windborne debris impact without shattering. These windows should also be equipped with high-performance seals and frames to prevent water intrusion during heavy rainfall. Additionally, the guidelines emphasise the integration of a continuous load path design, ensuring structural elements are interconnected to distribute forces throughout the building and minimise the risk of localised damage.
Moreover, the guidelines promote passive design strategies to enhance the campus's resilience without relying on mechanical systems. They include strategically placed openings to facilitate natural ventilation and to reduce wind pressure buildup, as well as reflective roofing materials to minimise solar heat gain and energy consumption. The guidelines also stress the importance of landscaping features, recommending native vegetation and permeable surfaces to absorb stormwater and mitigate flooding risks.
When observing the phenomenon of floods, it is crucial to understand the distinction between floods and the more rapid and unpredictable manifestation known as flash floods. Floods, in their broadest sense, occur due to an overflow of water onto typically dry land, originating from various sources such as heavy rainfall, snowmelt, or river and stream overflow. While these riverine floods could unfold over a span of days or weeks, flash floods can transpire in a matter of minutes or hours.
Unlike floods that affect larger river basins, flash floods impact smaller, localised areas. They are characterised by their rapid onset and swift-moving water, often carrying debris and posing significant dangers to life and property. Several factors contribute to their occurrence, with intense rainfall being a primary catalyst. When rain falls relentlessly, especially over urbanised areas with impermeable surfaces, rainwater cannot penetrate. Consequently, excess runoff accumulates, overwhelming drainage systems and triggering flash flooding.
In recent years, flash floods have become synonymous with urban areas, exemplified by their occurrences in Kuala Lumpur, Malaysia. The SMART Tunnel (or Stormwater Management and Road Tunnel), a notable engineering feat, stands as a testament to the city's efforts to address such challenges. The first phase, which involved the construction of the stormwater tunnel, was completed in 2007. The second phase, which added the motorway component, was completed in 2012. Designed to mitigate flooding, the SMART Tunnel has significantly reduced its occurrences in the city centre. However, despite its impressive record in managing floodwaters, it has limitations. During particularly intense storms, its capacity can be overwhelmed, leaving certain areas vulnerable to flash floods.
In addition to technological solutions like the SMART Tunnel, attention should also be given to exploring greener prevention and mitigation measures, such as integrating bioswales and retention ponds. Bioswales, a type of green infrastructure, are shallow, vegetated channels or ditches strategically designed to slow the flow of stormwater. Lined with native grasses and plants, these engineered features also serve as natural filtration systems, trapping sediments and pollutants as water passes through. By promoting infiltration into the soil and reducing the volume and velocity of runoff, bioswales play a pivotal role in preventing flash floods and erosion while improving water quality.
Meanwhile, retention ponds, also known as detention basins, are man-made bodies of water specifically constructed to store stormwater runoff temporarily. Typically designed as excavated depressions or basins lined with impermeable materials, retention ponds serve as reservoirs during heavy rainfall events, capturing excess water and allowing it to drain slowly or releasing it at a controlled rate. By holding back stormwater, retention ponds reduce the peak flow of water, thus minimising the risk of flooding and erosion downstream.
Both bioswales and retention ponds offer a range of environmental and societal benefits beyond flood control. In addition to their stormwater management capabilities, bioswales provide valuable habitat for wildlife and contribute to urban greening efforts. Their aesthetic appeal and potential for recreational use make them a preferred choice for enhancing urban landscapes while promoting ecological resilience. Similarly, retention ponds offer opportunities for wildlife habitat creation and recreational activities such as fishing and birdwatching, further enriching the urban environment.
As the construction industry charts its course into the future, it holds considerable influence in shaping our built environment. With architects, engineers, contractors, and administrators at the helm, we possess the collective power to spearhead resilient construction practices. From towering skyscrapers to humble homes, let us imbue every brick and beam with the spirit of adaptability. Together, we can build a world where natural disasters cease to dictate our fate, where our buildings endure the elements and emerge stronger from these 'storms'.
Ali Moossajee is a Bachelor of Quantity Surveying (Honours) alumnus of Taylor's University. He regards reading, writing, and learning as avenues for personal and professional growth, and he embraces the value of knowledge sharing. He lives by the motto, ‘We rise by lifting others.'
