Heart-rending incidents of failing structures leading to immense loss of human lives are on the rise. In Mumbai alone, there are reports of a major building collapse every few weeks. Recently more than 40 people were trapped in the collapse of a threestorey building in south Mumbai. Research reveals that about 500 buildings in the city are similarly vulnerable.
While we are progressing at a fast pace, structural safety concerns of buildings are getting less and less attention, it seems. Buildings are collapsing even due to rain! At least 17 persons were killed when recently in Coimbatore, heavy downpour led to the final collapse of few already structurally weak houses.
In most parts of the country, structural safety concerns are totally ignored. Around 40% people are living without any structural safety certificate, according to a private survey. In fact, 18% of them do not even know what the certification is about. It is only after some calamity that we tend to take notice of the seismic compliance, structural safety and/or, earthquake resistant certificate of a building etc.
Data collated by the National Crime Records Bureau (NCRB) indicates that 38363 people lost their lives due to the collapse of various structures in 37514 incidents between 2001 & 2015.
Majority of people never demand such a certificate for their homes and this lack of awareness encourages private builders to exploit the safety requirements. Things fall apart when even a heavy downpour leads to a collapse and loss of lives.
Structural Safety holds dire importance in construction, primarily because compromises in this area leads to LOSS OF HUMAN LIFE. Data collated by the National Crime Records Bureau (NCRB) indicates that 38363 people lost their lives due to the collapse of various structures in 37514 incidents between 2001 and 2015. A total of 1885 people lost their lives due to collapse of structures in 2015. The latest data available is only up to 2015. The number of incidents of structure collapse has been going up and down in the last 15 years. The highest number of such incidents occurred in 2011 when 3125 structures collapsed. The total number of incidents was more than 3000 each in 2008, 2011 and 2013. In a welcoming sign, the number of incidents was less than 2000 in both 2014 and 2015. These are the only two occasions when the number of incidents was less than 2000. On average, there were 7 such incidents of structure collapsing per day between 2001 and 2015.
The NCRB categorises the data on collapse of structures into 5 different categories. Between 2001 and 2015, more than 15000 people lost their lives because of the collapse of residential buildings which account for about 40% of all the deaths. A total of 3981 people lost their lives because of the collapse of commercial buildings or 10% of the total death toll. Collapse of dams & bridges together accounted for about 4% of all the deaths.
Rest of the 45% of the deaths were due to the collapse of other structures like flyovers etc. As expected, most such deaths took place in the bigger states. Uttar Pradesh accounted for most number of deaths (5690) followed by Maharashtra (4237), Gujarat (3961), Tamil Nadu (3457) and Madhya Pradesh (3353) in the top five. More than 1000 people lost their lives due to collapse of structures in each of the eleven states. Of the bigger states, Punjab, West Bengal, Odisha & Kerala had less than 1000 deaths in 15 years.
Most common causes of structural failures
1. Poor communication between the various design professionals involved, e.g. engineers involved in conceptual design and those involved in the supervision of execution of works.
2. Poor communication between the fabricators and erectors.
3. Bad workmanship
4. Ignoring load bearing capacity
5. Compromises on professional ethics
6. Ignoring safety codes and specifications leading to misinterpretation and misapplication.
7. Weak foundation & compromises on materials used
Must-Do’s for Builders & Architects for Safer Buildings
When a building is weak or built on weak grounds, it becomes more prone to collapsing under unsteady conditions. More than 60% of India is seismic prone and needs to have designs according to the seismic conditions. Earthquakes are divided into 4 zones on the basis of magnitude and severity.
1. While working in a seismic zone 3 or 4 or 5, building designs must be conforming to the relevant provisions of National Building Code of India
There is a mandate from National Building Code that every 3-5 years there has to be a technical audit of all the buildings which are more than 15 meters in height. But this is not being implemented at all. There is also a new tall building code that has come in to the market three years ago but many people are not aware of the important provisions of this code. This code covers buildings which are more than 50 meters in height. Builders & Architects who are working with buildings which are 50 meters in height must be conforming to these codes.
2. Geometrical irregularities are totally not recommended while working in seismic zones. The more irregular the building is the lower will be its performance in a serious earthquake.
So we must stick to regular buildings, to solid geometries as much as possible and as much as your architectural aesthetics permit them to be. If you have to have offsets, remain within the limits given by the IS codes. Go through the IS codes and ensure that your building geometries are regular and they conform to planned and vertical regularities.
3. Make efforts to go regular because it has been found worldwide that regular buildings have performed much better. For instance, if you look at Tokyo, even their high rises, maybe 100 or more storey tall, stick to a regular geometry and still their buildings look very beautiful. So, do not think that regular buildings cannot be made architecturally & aesthetically beautiful.
4. Regular technical audits of buildings must happen. In Chapter 2 of National Building Code, there is a clear provision of carrying out regular technical audits. All the buildings which are more than 50 meters in height must be audited after 3-5 years regularly. While discussing the issue of ‘Lack of Structural Safety in Buildings’ in a panel discussion at WADE ASIA 2019 conference, Structural Engineer, Ms Sangeeta Wij, MD, SD Engineering Consultants LLP, Delhi put a lot of stress on such audits.
Architect Chenthur Raaghav Naagendran, Co-Founder, A + R Architects, Tamil Nadu, reinforces the importance of regular technical audits of buildings, “Regular audits in intervals of 3-5 years that NBC has introduced is very important. The first point under audits is that we check for cracks, we check for primary members which show the structure’s failure, if there’s deformation or vibration inside. So when we walk on a site we come to know which member is failing. But how do we prevent them is what we do in design. We can use several software for the purpose.”
5. It is advisable to stick to good old expansion joints, especially while doing very large developments with 3-4 basements. You must try and go for basement parking rather than stilt parking because basement parking definitely adds to the structural safety of the entire building complex.
6. Say no to hidden beams and floating columns.
7. Let go of isolated footings or pile caps if your soil is poor and always tie them at foundation level as well.
8. Avoid having flat slabs, PT slabs, and Precast structures in seismic zones. In America, they do not do any flat slab buildings in high seismic areas like Los Angeles or California, or even in New Zealand, or Japan, but in India our code makers are little too slow in accepting and acknowledging this fact. However, revised code does not allow you to do flat slabs anymore.
9. No compromise should be made on materials: Longevity of buildings is increasingly reducing. A major cause of concern is the material used. Cost cutting exercises are leading to compromises in quality of materials used.
Ar Naagendran shares, “If we are making our structure economical by compromising on materials, the impact or the outcome like what we had in Delhi recently is something that the whole nation has to think upon.” High rise buildings are getting built rampantly all over the country. Many of these buildings, while fulfilling the dream of owning a home, are exposing human lives to danger. According to Ar Naagendran, architects must pay a lot of attention to details during construction. They must understand that in case of high rise buildings, there is a lot of lateral load, wind load. They must pay attention to tackling this torque, tackling the angular momentum, flexibility of materials, avoiding rigid joints etc. By working with engineers, structural engineers, consultants, they must focus on making the structure adaptable to earthquakes, cyclones etc., tweak the design if required.”
Architect Manu Goel, Partner, Novarch, Delhi, seconds the thought by pointing out, “Structural safety is something that has to be an absolutely inherent thought whether it is just related to building itself, or it is how we are reinforcing our roads, for example, when we do master planning projects. Safety is not just structural safety but it is also fire safety, and safety in various ways. So once that as a thought gets ingrained in us and our community’s architects, I think it will be a more holistic process.”
According to her, “structural safety may not be just limited to audits but actually making sure that your buildings are on time to time basis assessed for various kinds of safety measures whether it is fire evacuation doing drills, making people aware. You may have the best provisions in the building but if the users are not aware of how to access or use those provisions it might actually not work when there is a hazard of that kind. So earthquake safety being one of them, fire being another one, structural safety at inherent level being another one.” Lot of importance is being given today on green building certifications etc., but what one needs to first focus on is solidifying the structural safety requirements. As Apoorv Vij, Director, Technical Development, GCBI India points out, “People often come to us and talk about structural safety or water proofing etc. From our perspective, our assumptions are that without that a building can’t be built, so while we are voluntary, we do assume that water proofing, structural safety by default is a mandate and would be followed.
Municipal approval of building designs is mandatory but it is more of an eye wash, because the people who are checking the drawings are not looking at the total design as such. They just look for some kind of a vetting from a premier engineering institute
- Ar Gian P Mathur, MD, GPMA, Delhi
The Nation Building Code & other state-level initiatives
The National Building Code (NBC) regulates safety in construction activity at present in India. Upon failure to comply with the codes, the builder of the structure is penalised and in certain cases, the approval can get cancelled or the building may get demolished as well. There are also specialised rules for multi-storey and public buildings in almost every state independently. There are still many small and medium sized towns which do not have building bye-laws. Such towns are confronted with excessive coverage, encroachment and haphazard development resulting in chaotic conditions, inconvenience for the users, and disregard for building aesthetics, etc.
However, some states have also made it mandatory for property owners to submit a structural safety certificate at the time of property registration. In 2011, the Delhi government made the structural safety certificate mandatory for property registration. In 2014, Gujarat government made the structural safety audit mandatory for old buildings. Till 2018, there were 10,000 buildings that were still lacking the structural safety certificate. After the devastating episode of four buildings collapsing over the period of 1year, the structural safety certificate was made mandatory for buildings older than 30 years in Vadodara in June, 2019. Taking the stride higher, Chandigarh has made the structural safety certificate from a qualified empanelled structural engineer registered with it, mandatory for availing the benefit of the regularisation scheme.
In May, 2018, The Maharashtra Real Estate Regulatory Authority (MahaRERA) asked to act against 293 real-estate projects from all over the state, mostly outside of Mumbai, that are being developed without requisite permissions.
It is not the beauty of a building you should look at; it is the construction of the foundation that will stand the test of time. - David Allan Coe
The ‘Pagdi’ buildings of Mumbai were also been taken under the same rules of RERA in 2018. Under the RERA Act, construction defects must be rectified by developers free of cost for a period of two years, and structural defects, for a period of five years. A project’s construction and sale can begin only after the builder has obtained all statutory approvals. In addition, developers cannot make changes to original plans or the structural design and specifications of the building, unless they get the consent of two third of the customers.
Are the Rules actually Getting Followed?
While NBC is laying the rules, are they actually getting followed?
The codes are revised, new codes are being brought for implementation, but unless the builders follow them, we are not going to have safer buildings. In Delhi for example, if a builder is building in an earthquake prone zone 4 or zone 5, a 12 or 13 storey housing, from foundation it may come up to 50 meters in height. In that case he is not allowed to have beams and columns systems anymore. But people are not even aware of this rule, and thus rampant abuse is going on, leading to catastrophes that make us believe, “our lives are just worth a natural calamity.”
Negligence begins right at the design level.
The process of municipal approval of designs remains flawed. While lack of skilled workforce remains a constraint, designs vetted by premier academic institutes are not even scrutinized properly. We definitely need stronger systems in place.
It is time to act and not just listen when experienced architects like Ar G P Mathur says, “Municipal approval of building designs is mandatory but it is more of an eye wash, because the people who are checking the drawings are really not looking at the total design as such. They just look for some kind of a vetting from a premier engineering institute. That is something which NBC should take up. But right now this is the practice. And unfortunately they also don’t do the detail checking as such, nobody does that. Municipalities don’t have authorised or qualified people to be able to challenge that design. Consequently, when a construction goes on site, it is not even properly supervised.” Ms Wij agrees to the state of affairs by saying, “Our municipal authorities in 99% of the cases do not check structural analysis design or drawing before giving you approval to start construction. ‘Anonymous institutions’ vetting is only a formality
NBC is making efforts to improvise the situation but a lot more needs to be yet done.
Ar Mathur highlights, “I feel that NBC’s new rules are not being made stringent. They have been conducting lot of seminars in all cities. I’m a part of Indian Building Congress and they have been working with them, and they have conducted a lot of seminars but still it has not been properly enforced.”
Architects rely on structural consultants to a great extent, but even then all is not well
Architect Mathur lets us know, “Structural consultants try to follow the rules, but in most of the cases there is a lot of conflict of interest. The builders do not want them to follow, do not let them follow and that is how it comes back.”
Ar Chenthur counters the thought by saying, “Not just structural engineers have to follow codes, architects, designers and even end users should be aware of these codes and make sure that they are being followed.”
Ms Wij reinforces the point. She shares, “If a building falls today what our government does is just hand over compensation to the user, why should our taxpayers’ money be paid as compensation to a user who changed the use of his building without making sure that his structure was safe enough for the changed land use. So the onus lies on the client as well. And onus lies on the architects to plan things correctly and also on the structural engineers to implement the code compliance correctly.
Why not take professional help?
Many complain that qualified people who can vet designs for structural safety are not available in adequate numbers. This leads to leeway and thus non-compliance of the safety codes. When architects raised this issue at WADE ASIA’s Panel Discussion,
Ms Wij gladly shared that teams of competent structural engineers are getting formed all over India. Things are improving and people involved at design level must engage with structural engineers for creating safer buildings. Architects must hire professionals. There is a national body of Indian Association of Structural Engineers, and many similar bodies all over India. In south, we have Association of Consulting Civil Engineers and many competent professionals available, so architects & builders should go ahead and get their buildings checked for safety. We agree with Mayank Sharma, an interior designer, when he says, “We have very skilled technicians and skilled engineers and technocrats, the only thing lacking is loyalty to institute and society. This percentage is very few but due to their negligence, everyone has to suffer.
The importance of structural safety is taken for granted hugely even in the presence of strict framework. The rise of unauthorised and illegal structures across the country can’t be ignored anymore. Architects, engineers, builders must come together and work collaboratively towards creating safer, stronger buildings that could stand the test of time.
ROLE OF MATERIALS IN STRUCTURAL SAFETY
Ancient structures were not just strong and built carefully but intelligently. In those days, there were hardly any methods to compare the material strengths but still the choices were so excellent that many of the ancient buildings are still standing tall, while new ones are collapsing like paper structures.
Speed and cost constraints are leading to increasing choice of poor quality materials for construction. These materials are bringing lot of risks to the buildings constructed using them. The potential risks include water ingress (access of moisture into the fabric of a building), fire hazards etc. Use of materials such as asbestos, synthetic mineral fibre (SMF), polychlorinated biphenyls (PCB) and lead in building paints are also hazardous.
Recently, many accidents happened due to use of flammable external cladding as part of the building structure. For instance, research shows that the polymer core makes ACP products dangerous in a fire, and the amount of polymer core should be limited to a maximum of 10 per cent. A safer option is to use ACPs which are fireproof.
To have stronger buildings, it is advisable to use steel-reinforced concrete because the embedded steel increases the ductility of the material. Buildings made of structural steel offer the highest ductility, allowing buildings to bend considerably without breaking. Wood frames are more prone to fire hazards, so to improve fire safety, it is advisable to choose brick, stone masonry, precast concrete panels or structural insulated panels.
It’s time to accept the fact that if new products and processes aren’t tested in labs, citizens in the real world will have to pay the price. Laboratory tests such as fire safety, water ingress protection and structural performance can significantly change the way building cladding is built, look and perform. Building products that are prefabricated, lightweight, have good thermal and acoustic properties and require minimum on-site processes are the way of the future.