By Dato’ Ir. Dr. Gue See Sew
The tragic collapse of BLOCK 1 of the Highland Towers on 11 December 1993, and the remaining abandoned blocks is a reminder of a tragedy that struck the nation.
Indeed, Highland Towers is often cited as one of the reasons to oppose hill-site developments.
There is no disputing that the country learned important lessons from the incident, and it is these lessons which also tell us why hill-site developments in themselves are not the problem.
In fact, hill-site developments, when done right, actually improve the safety of the hill itself and adjacent areas.
All hill-sites with steep slopes carry the risk of slips. Even natural, undeveloped hills. This is why when we drive along highways or rural roads past hilly areas, it is not uncommon to see landslides even when there are no development or logging activities.
In Geotechnical Engineering, we use a term called “Margin of Safety” or “Factor of Safety”. The lower the Margin of Safety, the higher the risk of landslides.
With natural, undeveloped slopes, a lower Margin of Safety is acceptable, but again, this does not mean there is no risk of landslides. However, in Malaysia, when a hill is developed, there is a minimum requirement for a Factor of Safety of 1.5 for treated slopes.
This is actually higher than the Margin of Safety in Hong Kong. So the net result of hill-site development in Malaysia is that the hill or slope becomes safer than if it was not developed.
In a local context, hill-site development has come a long way from Highland Towers. There are very robust enforcement systems in place to ensure developers adhere to very stringent local council guidelines.
The entire process of hill-site development includes the involvement of independent, third-party consultants, and the use of proven techniques such as soil nailing to ensure the safety of any hill-site development.
The actual development of a hillsite employs proven techniques to stabilise and strengthen slopes so much so that buildings can be built to last without their inhabitants ever having to lose sleep over their safety.
Such techniques include the use of reinforced and stabilised slopes. These are often used in the construction of huge infrastructure projects including dams.
Rock bolts are another common technique used to reinforce rock slopes, while soil nailing helps strengthen soil slopes.
These techniques are among the many employed to ensure the safety of their projects.
It is also important to remember that hill-site development is not a one-off process that ends when construction works are completed.
Hill-site developments are subject to rigorous, scheduled maintenance to prevent erosion. The building owner must employ the services of engineers to conduct a thorough inspection of the property and surrounding slopes.
The combination of rigorous safety requirements at both the construction and maintenance stages of hill-site development compels us to change how we view such developments.
At a time when space is becoming increasingly scarce and the need for housing constantly rising, the merits of hill-site development are clear.
However, the all-important caveats – strict adherence to regulations, the leveraging of scientifically-backed techniques and a commitment to safety – must always apply.
Stakeholders should remain open-minded and be receptive of efforts by developers who can play an important role to strengthen hill-site developments.
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