Since the monsoon has hit us, it has become a daily affair to read about news of fatal construction failures.
A lot of buildings that have collapsed in rains appear to be made from the wonder material, i.e. reinforced cement concrete (RCC) that Indian architects have fallen in love with since modern architecture arrived on our shores.
As we have never believed in questioning climatic appropriateness of anything that we import, RCC has replaced every traditional construction technology we once had, so today most Indian cities are full of 40-50 year old RCC buildings, and it seems that we are now in for a disillusionment that is likely to cost us dearly.
Since its invention, RCC has become engineers’ darling because it has allowed integration of tensile strength of steel with compressive strength of concrete, and as mild steel and cement concrete have very similar coefficient of thermal expansion, the problem of differential expansion is also solved. This has led to a situation that most of our buildings now use RCC as the sole structural support system.
For structural designers, steel has served like steroid injections to a body as it increases the strength of a structural element hugely, but there is a catch in the game that we have failed to see, i.e. RCC works only till the steel encased within concrete has not rusted, and unfortunately this is where our location on the globe comes into the picture.
If we look at climate of Ahmedabad, a building in our city will expand under 47 C heat in summer and contract under 7 C chill in a year. Though this expansion-contraction doesn’t lead to structural failure in RCC, it leads to concrete developing microscopic cracks.
When rain or drain water gets an opportunity to penetrate RCC through these cracks, it leads to rusting of the steel bars. As these bars get eaten away by corrosion, the RCC member loses its strength leading to the collapses that we are seeing now.
As people who love to be self-critical, we may like to argue that there is nothing wrong with technology and problems are caused because of crooked contractors using substandard materials and poor execution, the fact is we had not anticipated that our love marriage with RCC will require constant maintenance it needs because of the very nature of its design.
It is clear that our obsession for RCC will cause us a lot of pain in terms of loss of human lives or cost us a lot of alimony that we can’t afford because we are far too committed to the relationship to turn back now. So, we need to start a slow but deliberate process to curing us off this toxic relationship, at least in one sector.
As we are on a spree of making cheap homes for economic weaker section, we need to ensure that they don’t turn into death traps after thirty years as the ones that we have inherited have now become.
We need to stop trying to save space by opting for thin non-structural walls but instead, ensure that walls are thicker and participating in the load bearing, whereby ensuring that RCC is not the sole structural system.
It may mean more costly and a bit low rise buildings as self-weight of structural walls will increase even the RCC design requirements, but it will give us buildings that will not collapse like house of cards, even during an earthquake.
On the other hand, we also need to work on improving our relationship with RCC by engaging in research to make it more suitable for our weather.
Like any one-way love affair, the onus is upon us to uphold it before it turns foul.