Are
multi-stories building in our areas safe? Were they constructed following the
code, and their current usage is according to where it was designed? If the
structure would damage or collapses, those affected are not only people who
dwell and work in the building. Their neighbor, local livelihood, and public
services will also be affected. Hence, the government and building owners have
to conduct screening on its safety to minimize the risk and, at the same time
to provide proper assistance when the hazard turns into a disaster.
Screening and analyzing risks of high-rise buildings
There are
more than 23,000 high-rise buildings above 100 m in height worldwide.[ii]
These buildings are exposed to hazards, but their vulnerabilities depend on age,
height, use, building quality, subsoil, symmetry, and regularity.[iii]
For instance, regular and symmetrical buildings are more robust than irregular structures
such as L-shape, which might have additional loads, such as twists, due to earthquakes.
On the age part, for instance, on screening 98 high-rise buildings with 8-15
floors in Surabaya, Indonesia. It was found that 21 buildings have fallen into
the vulnerable category due to being built before 2002, in which the earthquake
regulations have not been applied in Indonesia.[iv]
Since many
buildings have to be assessed on their seismic vulnerability, large-scale rapid
screening should be conducted. Currently, some tools can be used, such as FEMA
P-154 Rapid Visual Screening[vii], there is a web-based[v],
and also there is an Android application[vi]. But even if large-scale screening using those
tools is launched, the screening quality will depend on the engineers’
capacities and experiences. Those data should be analyzed and interpreted by experienced
engineers to identify the vulnerability and, later on, how to strengthen them
seismically. Getting the screening recommendations will take considerable time as
so many buildings need to be checked.
Even if the
recommendation reaches the building owners, there is no guarantee they will immediately
strengthen it even if they know their building is vulnerable to earthquake. Seismic
strengthening, even if it is more economical rather than building a new one
after a disaster, many people still need to find this initiative as an
investment. It is increasingly costly if there are many vulnerable parts in the
building. On the other hand, there is no enforcement for the building owner to
retrofit their buildings seismically. Also, there is no incentive for building
owners to apply retrofitting. Hence, there should be regulations and incentives that
every building owner can be responsible for the safety of their buildings, whether
it is an apartment or an office building.
Risk
reduction measures and preparing the response in the urban context
The data and
analysis are valuable information for the government and S&S practitioners.
The risk and its magnitude can be mapped for contingency planning. For instance,
how many buildings, local businesses, and public services would be affected if
an earthquake happened in a particular magnitude? There should be sufficient
local capacities to respond to the disaster at desirable times.
The developed
local capacities should be able to support affected people who lost their
dwellings according to their circumstances and recovery pathways. The support
also should not diminish the affected people’s capacities to self-recover. On
the other hand, government and S&S practitioners should strengthen the
self-recover initiatives with sound technical guidance. This is to ensure a
safer rebuild in more sustainable ways.
As other
sectors should also be involved in recovery, local government and the S&S community
should support the market’s reopening through shelter assistance. The
assistance should trigger a multiplier effect through the construction job
market and building material market, which is massively needed during
rebuilding. In many parts of the world, the construction sector in high-rise
buildings is widely known as the prime mover of economic activities. They will draw
other businesses to participate, such as transportation that brings
construction materials, restaurants, communications, etc. The government should
have a strategy to maintain market stability; otherwise, at some point, there
will be a scarcity of construction materials or the job market. This
instability would lead to inflation which might hamper the reconstruction
process.
S&S
practitioners might provide training for builders to improve construction
practices and help them obtain builder certificates, which also need to work
on. These builders with particular skills can work in middle or high-rise building
construction since workers must show their credentials before being hired.
All of these
are to improve responder capacity on the whole level, from the beginning, which
is preparedness measures to the reconstruction phases. On the other hand, if the
building owners follow the recommendation from the screening, many buildings can
be seismically strengthened, then the level of damage will not be massive.
Arwin
Soelaksono
Photo taken by: Hazal Güverçinci
[i] Cochrane
S.W., Schaad, W.H. Assessment of Earthquake vulnerability of buildings. 1992
[iii] Cochrane
S.W., Schaad, W.H. Assessment of Earthquake vulnerability of buildings. 1992
[iv] Wahyu
Riyanto et al 2020 IOP Conf. Ser.: Mater. Sci. Eng. 739 012040` Earthquake
Vulnerability Assessment of High-Rise Buildings in Surabaya using RViSITS
Android Application
[v] Kassem.
M.M, et. al. Assessment of Seismic Building Vulnerability Using Rapid Visual
Screening Method through Web-Based Application for Malaysia. 2021
[vi] Wahyu
Riyanto et al 2020 IOP Conf. Ser.: Mater. Sci. Eng. 739 012040` Earthquake
Vulnerability Assessment of High-Rise Buildings in Surabaya using RViSITS
Android Application
[vii] Rapid Visual Screening of Buildings for Potential Seismic Hazards: A Handbook Third Edition FEMA P-154 / January 2015
