Sunday Times 2
Dusting off collapses with the rumble of regulation
There is no need to elaborate that the collapse of buildings or any other structure will result in very grave consequences. It may lead to loss of life and serious injuries not only to the occupants but to the neighbours and the people around when the collapse occurs. These will be in addition to the loss of valuable physical assets and further legal claims.
A building which collapsed in Wellawatte on May 18.
We frequently hear about building failures in crowded cities across the world. However, until recent times there were not many building failures reported in Sri Lanka. It is possible that the main reasons were,
(a) No major loss of life
(b) Most of the buildings in the country were low rise structures
(c) Building failures do not catch the eyes of the media.
It is common knowledge that the failures
of buildings is mainly due to:
(a) Inadequacy in the structural design and unsuitable ground conditions
(b) Serious shortcomings in the construction phase
(c) Upgrading of existing buildings such as construction of additional floors without proper engineering assessment.
In Sri Lanka, during the last decade construction activity has been moving in a rapid phase. We could note that many new buildings with multiple storeys are being built in practically all the towns and along major roads. Now there is also news that plans are afoot to build a tower block in Colombo that will be world’s tallest.
Unless these buildings are designed and detailed by competent engineers, and built under their supervision, we could expect many non-compliances to the relevant structural engineering standards. Non-compliances may result in failures during the construction phase as well as during the occupation. To prevent such man made disasters, it is imperative that the roles of the Government and the local authorities who approve the projects need to be strengthened.
Construction of a building will go through two stages, i.e. design phase and construction phase. As I understand, at present the local authorities in urban areas need to approve the design documents and issue a building permit to allow the construction phase of a building. In this process, if the plans submitted involve a specific engineering design, it is mandatory for a chartered civil or structural engineer to sign and approve the plans.
Here the questions will arise,
Whether the local authority has access to the register of chartered civil/structural engineers maintained by the Institution of Engineers, Sri Lanka?
Are the chartered engineers who sign the plans experienced in the type of structural design, to allow them to vet and approve them?
What will be the responsibility of the structural engineer if the building fails during or after construction?
As I am aware, in the present system, the engineer who designed the building could become responsible only if it could be determined through a lengthy legal process. As we know, such a process will be too arduous and there will be many loopholes that will permit an unscrupulous person to shun the responsibility.
In many countries, there are built in regulations to prevent such failures in all the stages of a project, including investigation, design, construction and the maintenance phase.
These rules impose the total responsibility for the design to the design engineer. To make the process transparent, the design engineer issues a Design Certificate or a Producer Statement identifying all the relevant design standards. It is mandatory for the design engineer to have an insurance policy for his professional works. The purpose of this policy is to indemnify the owner of the building if any failure happens. Generally the producer statements are in a format approved by the local institution of engineers in the country. Council can approve the building applications only on vetting the acceptability of the said documents.
Such a process needs national regulations that will clearly cover all the stages of the building permit process and identify the responsibilities of the relevant parties. I believe that the Urban Development Authority (UDA) will take the responsibility of drafting the regulations on this issue that is very critical to the country. The Institution of Engineer Sri Lanka will also have a role to play to make sure that the engineer who signs the design documents will take the total responsibility for the design.
As notedd earlier the failure of a building may be the result of non compliance with the engineering standards at the construction stage. It may be due to the wrong selection of materials or the adoption of erroneous methodology. Simple examples are the use of low grade steel reinforcements or using weak structural concrete, or untreated low-grade timber. It may also be due to the adoption of inappropriate technology or using short cuts during the construction stage. There are many examples in Sri Lanka where the wrong methodology used in construction will result in serious inadequacies and failures during usage. One example I could recall is the leakage from concrete walls and the basement floor in a medium rise building built in Rajagiriya for a very important organisation in the country. It was found that the concreting in the basement walls went ahead although the poker vibrators broke down in the middle of the process. Here the construction was carried out by a prime structural engineering contractor, but without adequate supervision by the consulting engineer.
It is not an exaggeration that the specifically designed structural work needs to be supervised by a qualified engineer who very well understands the design methodology and the controls needed in the construction stage. However, there is no mandatory requirement under the building approval conditions in Sri Lanka that the building owner needs to obtain the services of the design engineer. Therefore, the design engineer’s involvement in the construction phase will depend on the contractor or the owner that will be mainly decided by the financial implications. Such decisions may affect the compliance to the design standards in the construction phase.
If the structure fails during or in the post construction stage, the design engineer cannot be held responsible as he had not been involved during construction. Therefore, the need arises to impose conditions under the building approval to obtain the services of the design engineer or another chartered engineer to supervise the construction phase and to certify it. In many countries, this is facilitated by the need for the supervising engineer to issue a certificate such as a Producer Statement – Construction at the completion of the construction phase. In format, this is similar to a certificate issued to the cover the design but will only cover the construction stage. Naturally the issuer of the Producer Statement – Construction needs to carry an insurance policy that will cover the value of the structural work in the building to indemnify the owner in the event of a building failure.
Finally, it needs to be noted that all the matters discussed above are relevant to any built-up structure, whether it is a building, highway bridge, water reservoir, tunnel or an irrigation dam. I hope that this article will attract serious attention from the engineering profession as well as the central government and local authorities who will have to face the consequences when the structures fail.
(The writer is an engineer)