Need of controlling a Building collapse
If you look at the news papers these days, it is full of reports on building collapses. Let it be Bangalore, Kerala or up north of India, every where, everywhere, even in the US there has been some or the other report on a building collapse. Some of the collapses may be due to natural calamities. Still may be those could have been avoided if proper structural engineering was adopted. Mitigation of structural failures is the need of the hour.Let me try to include a few important steps that can avoid similar building collapses and failures in the future.
Need of Consultants on Board.
Many small and mid-scale Projects are done without qualified consultants, especially structural consultants on board. Also note that, many think that an architect takes care of entire points including structural designs. This is not correct. An architect’s role is to ensure the functional wellbeing and aesthetics of a building project. He might appoint a structural engineer, however there is a perception that if an architectural drawing is approved by the authorities, then it is safe.
A structural Engineer should be on board much before the Architectural drawings are finalized. This will enable a structural consultant to propose a proper structural scheme that will perform and meet all stability and strength criteria. If the structural scheme is not proper, there can be many undesirable compromises and adjustments that can become fatal. Also note that most of India is a seismic zone and it is very important to do proper seismic resistant design and detailing of all building projects.
By proper scheme of the building, I mean the below mentioned points
Proper geometry of the building – Common people are not aware that irregular and fancy shape and form of the building comes with higher seismic demand. This means that the chances of a building collapse are more unless it is attended carefully by an experienced structural engineer.
Proper column location, orientation, Shear wall positions and sizes – Common users are clueless about these requirements and only cares to see that columns do not clash with the functional requirement.
Certain amount of structural risk analysis and accident controlling measures shall go in to the design of a building.
As professionals, it is our responsibility to generate awareness among common people on the importance of all these aspects. Many still believe a smaller number of columns are more economic.
Similar to this, all buildings should have a Geotechnical engineer on board. Most cases, either SBC is asked to be assumed. Structural engineers are asked to double up as Geotechnical engineers and so on. Sometimes the role of a soil consultant ends with providing a soil report with SBC and the stability of slopes etc. are ignored. Many buildings collapsed are due to weak soil and lack of soil investigation. This will result in differential settlements and sometimes, failure of retaining systems. All these failures can be sudden brittle failure.
It is also important to avoid corner footings. In most cases the need of an eccentric footing arises due to compromises in setbacks.
Structural Scope
Many times, the structural engineer’s scope is limited to issuing structural drawings and occasional stage inspections. This should change and the scope of structural engineers and their fee should extend and cover a total supervision of the project. Alternatively, there shall be a Construction engineer/agency on record who is made responsible to ensure the adherence to structural drawings. It is always better if the structural scope includes this by also increasing the structural fees.
Structural Fee
Current Structural fee, in many cases are not adequate to cover the expenses of the consultants. This is surely affecting the quality of work. If a consultant has to use the best and leading software like ETABS, STAAD & REVIT and also spend enough time to validate everything, it needs a compensatory fee structure. It is high time that the professionals are paid well to ensure safety. The bylaws should include and enforce a minimum fee for professionals in addition to stating competence and roles.
Structural Approval
If you look at the approval mechanism in India, in most states and cities, it is pertaining to Architectural, functional approval. This will mostly look at if the setback rules are deviated, if the buildable area is exceeding, if the fire safety demands are met and so on. In many city bylaws, structural drawing submission is mandatory but not strictly enforced. This shall be strictly enforced. There are challenges for this enforcement.
If all construction drawings need to be submitted in advance, then the design development planning has to be meticulous. There shall be no much revisions after the designs. However, this only will improve the entire quality and the project time scales if there is a proper planning
The approval authority needs to have competent engineers to check and approve. Many times, this requirement comes as a hurdle. Many approving authorities don’t have experienced structural engineers on board to oversee approval of the vast number of projects. Proof checking can be an alternative which I have mentioned in one of the subsequent sections.
Structural Proof Checking
Peer Review of structural design and the methods shall be made mandatory. This will ensure capturing of design mistakes at an early stage. Either the approving authority should have a good technical knowledge and inhouse capability to check and approve the structural drawings or peer review shall be made mandatory. This is a good way to ensure adherence to code provisions and best consulting practices.
Enforcement of all building rules
The carefully drafted building rules shall be enforced strictly with out any compromises. There shall be no scope in getting a plan approved and build another one. A stringent verification of this by various agencies at different stages should be made mandatory.
Appointment of an experienced structural engineer and a peer reviewer shall be verified at the start of the project itself. The structural engineer, peer reviewer and the construction engineer shall sign off the drawings before commencement of construction.
Structural Alterations
There has been a lot of collapses in the past, when people do structural alterations in the building in the name of interior changes and functional changes. It is important to ensure that no RCC element in a building is punctured, drilled or removed in the name of changes. All these alterations need careful analysis and cross checks. In most cases, such drastic changes like removing a beam will not be possible. This needs to be verified by a qualified structural engineer. Approvals and checks should be made mandatory for any structural alterations.
Maintenance & Structural audit for Old Buildings
All buildings should have regular maintenance and this needs to be certified at a period of time. Maintenance record of all buildings need to be maintained inspected and approved. There shall be a structural audit of all buildings periodically and the old buildings need more careful monitoring and audit. In the recent past, there has been a lot of old buildings collapsing and it can be serious disaster if the collapse is disproportionate.
Summary
Most building collapses are avoidable. It is not so easy for a properly engineered building to collapse as there will be alternate load paths in the building. Following a robust design and checking process clubbed with enforcement of existing building rules and adding a few new rules to ensure maintenance and audit of existing buildings will almost ensure that our buildings will never collapse. It’s easy to achieve if there is a will to do it. It’s a collective effort between clients, consultant, authorities and the general public. We have realized the problem by seeing the collapses. Time to arise and awake!
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