Dr Lee (right) with the help of his students demonstrating how the structure of a small scale building will react on a shaker.
MALAYSIA’s proximity to the Pacific Ring of Fire – an area of significant volcano activities and earthquakes – makes it vital to incorporate safety features into buildings here, say experts.
“The nearness of our country to this seismically active area means that high-rise buildings will feel the wobble from these earthquakes though it is occurring 500km away,” said Dr Lee Hoong Pin, an associate professor from Inti International University’s Faculty of Engineering and Quantity Surveying.
“Seismic workshops held by the Institution of Engineers (IEM) proposed that buildings in Sabah where an earthquake measuring 6.0 on the Richter scale had occurred in 2015, be designed to withstand ground shakes that are equivalent.
“On May 9, the IEM also issued a statement for the minimum design standard for buildings in Sarawak and Peninsular Malaysia be set at a magnitude of 4.9 on the Richter scale,” he said.
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On how much it will cost developers to conform to new standards, Lee, who has consulted a practising engineer, said the estimated sum will usually fall within the range of 5% to 15% of the total building cost.
“As a developer, costing is important but so are the lives of the buildings’ occupants. As such, it is the duty of engineers to safeguard public interest. Cost wise, it is possible to find a balance in building design and precision engineering methods,” said Lee.
Lee, who had guided his students to win earthquake design competitions nationally and internationally since 2015, said not all structural strengthening methods will necessarily require hacking but occupants will need to be evacuated temporarily.
“Installation of bracings, including the shift shape variety which has absorbers to strengthen a building, can be done externally as long as they are connected to the structure system. These will play a part in absorbing lateral loads. Columns can also be wrapped in reinforced polymer fibre to improve their strength.
“The first step is to call in structural engineers to look into the types of rehabilitation work that can be carried out,” he said.
Regulations in place
Regulations are already in place for the design of building structures to withstand seismic activity, said Chin Lee Leng, an engineer and representative of the Association of Consulting Engineers (ACEM).
“The construction standard for seismic resistance for building structures is the National Annex to Eurocode 8 (EC8), officially known as MS EN 1998-1:2015. This standard is published by the Standards Department (JSM) which comes under the Science, Technology and Innovation Ministry,” said Chin.
ACEM was one of the organisations on the Earthquake Technical Committee that had contributed and supervised the development of this standard.
Chin said the new standard became a statutory requirement under the Uniform Building By-Laws (UBBL) when it was gazetted by the Federal Government on Dec 31 in 2021.
“Under MS EN 1998-1:2015 or EC8 standard, structural modelling and analysis for lateral loads arising from wind and earthquake activity must be carried out and assessed in the design process.
“The foundation and structural framing system for buildings must be designed to withstand forces arising from vertical as well as lateral earthquake loads. This is to ensure they would be able to withstand the additional bending and shear forces induced by seismic activities.
“The detailed structural plans and calculations of the proposed building shall be submitted to the local council before the start of construction. The submissions must also be certified by the project engineer who must possess a valid practice certificate,” said Chin.
The Indian Ocean tsunami on Dec 26, 2004, which hit Penang in the peninsula and the 2015 Ranau earthquake in Sabah, were among the seismic experiences that expedited and accelerated the establishment of the new standard.
“In 2015, the industry standard was still at EC2. This swift formalisation of a higher standard within the span of six years is an indication that stakeholders have realised the need to provide a clear direction and guideline on seismic design requirements in the Malaysian context,” said Chin.
However, it must be noted that the Street, Drainage and Building Act 1974 (Act 133) empowers the state authority to mandate building by-laws.
This means the respective states and federal territories (with the exception of Sabah and Sarawak) are still required to gazette these by-laws before they can be implemented by the various local authorities under their jurisdiction.
“Based on the implementation of previous amendments, it has to be noted that not all states follow the amendments to the federally gazetted UBBL in its entirety. A state has the prerogative to include sections that they deem will benefit the state and discard those that they feel are not,” explained Chin.
So long as high-rise buildings are constructed based on the requirements of the Uniform Building By-Laws, they are able to withstand a low level of ground shake, say experts.— GRACE CHEN/The Star
Chin said the IEM which had also played an active supervisory role in the Earthquake Technical Committee, had recommended that important buildings or structures particularly within the yellow, orange and red zones (refer to Seismic Hazard Map) undertake seismic vulnerability studies.
If necessary, retrofitting or strengthening should be carried out to improve the structural performance of buildings located in these zones.
Sixty active fault monitoring devices like this have been installed along fault lines throughout the country.
60 fault monitoring devices
To keep a look out for seismic activity, the Mineral and Geoscience Department (JMG) under the Natural Resources, Environment and Climate Change Ministry has installed 60 active fault monitoring devices along fault lines throughout the country.
Zamri says the potential earthquake areas in the hazard map are based on past seismic records.Of these, six in Sabah can be monitored in real time. Another six were installed in Selangor where a fault line is located.
JMG director-general Zamri Ramli said the installations in Selangor were necessary as the department had found a fault line with the potential to become the epicentre for earthquakes.
“Known as the Kuala Lumpur Fault (KLF), it runs from the Pahang-Selangor border across Selangor and Kuala Lumpur,” said Zamri.
The location of the six fault monitors are at Jalan Gurney in Batang Kali, Taman Eko Rimba Sungai Tua in Batu Caves, Masjid Zakaria in Gombak, Maahad Taafiz Al-Munawwarah in Ampang Jaya, Klinik Desa Kampung Padang and Masjid Ar-Rahman, both in Hulu Langat.
Information obtained on the rate and direction of active movement in the KLF zone, is used to interpret the potential strength and intensity of earthquakes that will occur.
It is also used to produce the Seismic Hazard Map (SHM) in 2019 and contains ground shake values to be used as a basic reference in designing earthquake resistant buildings.
The potential earthquake areas in the hazard map are based on past seismic records. The probability of actual occurrence has been given at 10% within a time span exceeding 50 years. Meanwhile, the probability of an earthquake recurring within the same area is 475 years.
“Data from the map is shared with the Public Works Department as reference for earthquake-resistant building design compliance, National Disaster Management Agency for earthquake disaster risk management in Malaysia and Standards Department for the purpose of updating and preparing the National Annex to Eurocode 8-Design of Structures for Earthquake Resistance.
“It is also shared with the Local Government Development Ministry for development planning in earthquake risk zones by the local authorities,” said Zamri.
The construction of earthquake-resistant buildings based on seismic hazard zones for development planning by local authorities is in line with the decision made by the Central Disaster Management Committee at a meeting in 2020.
“This map is also used as a reference in the development of guidelines on earthquake areas and public awareness programmes related to geological disasters,” said Zamri.
Zaidi says a majority of the tremors felt in Malaysia are usually related to earthquakes occurring in Indonesia and Philippines.Peninsular Malaysia has recorded several earthquakes at Bukit Tinggi in Pahang, within the Kenyir Dam in Terengganu, Kuala Pilah in Negri Sembilan, as well as Manjung and Temenggor in Perak, ranging between magnitudes of 1.6 and 4.6 on the Richter scale in 1984, 1985, 1987, 2007, 2009, 2010 and 2013.
Tremors in Klang Valley
Zaidi Zainal Abidin, who is principal assistant director of National Weather and Geophysics Operation Centre of the Meteorological Department, said a majority of the tremors felt in our region were usually related to earthquakes occurring in Indonesia and the Philippines.
“For example, earthquakes in Sumatra can be felt along the west coast states of Peninsular Malaysia. In the past 10 years, all 34 tremors recorded in the Klang Valley had originated from earthquakes in Sumatra,” said Zaidi.
So far, the strongest ground movement (PGA) reading recorded in Malaysia was during the magnitude 6.0 recorded on the Richter scale in the Ranau earthquake in June 2015.
On when a strong tremor would strike Malaysia, Zaidi said it is possible for earthquakes to reoccur in regions of active faults, but it is not possible to know exactly its time, location and magnitude.
“Within Malaysia, earthquakes are prone to occur where active faults like the Mensaban and Lobou-Lobou faults in Sabah are located.
“To date, Sabah has the most known active faults that have the potential to generate earthquakes,” said Zaidi.
