A disaster waiting to happen
By Rakesh Lohumi

A Gujarat-like earthquake could trigger off a "concrete avalanche" in Shimla where hundreds of high-rise buildings have come up on steep slopes.

Indeed, the manner in which some skyscrapers collapsed in Ahmedabad and Bhuj presents a frightening scenario for the hill town, which has over the years become a concrete jungle. The reinforced cement concrete structures are designed to be quake-resistant but the latest quake has exposed their vulnerability. Given the poor quality of construction and abject lack of concern for quake-resistant features, these structures are far from safe.

The destruction in this hill state will be much more than that was caused in Gujarat as the collapse of one weak structure atop a slope would spell doom for all others located downhill. There will be a "cascading effect" and the rolling debris will wipe out everything that comes in its way. In a state like Himachal Pradesh, which falls under seismic zone IV and V and where the probability of earthquakes of the magnitude of 8 points or more on the Richter scale is very high, high-rise buildings are the least desirable, However, in places like Shimla, Barog, Manali, Kasauli and Solan numerous six to twelve-storeyed structures have come up.

The situation is the worst in the state capital and its peripheries, particularly the cemetery and Kachighat areas. Here, buildings of all shapes and sizes have mushroomed, covering every inch of the steep slopes. Most of these buildings do not even have proper approaches and drainage. There are more than 9,500 structures in the old Shimla municipal corporation territory and another 12,000 in the newly merged areas. Out of these, more than 4,000 structures are unauthorised, while the total number of such buildings in the state is close to 11,000.

While the Public Works Department and the Housing Board take into account the seismic load while designing buildings, the same is not true for structures constructed by deputy commissioners, panchayats and other agencies. Nobody can guarantee the safety of private buildings as the municipal bodies and the town and country planning department do not examine the building plans from the point of view of structural safety. In fact, nothing has been specified in the building bylaws about structural design. The plans are examined only to ascertain whether or not they adhere to norms like floor-area ratio (FAR), setbacks, minimum size of rooms and the maximum number of permissible stores set by the government. Even these norms have been violated with impunity over the years. Successive governments made things worse by coming out with retention policies to regularise unauthorised constructions.

The architect-planner of the corporation, H.S. Kaushal, admits that the building plans are not examined for structural safety at any stage. There are just six junior engineers who examine building plans and regulate construction in 25 wards spread over 40 sq km. To get the structural designs of buildings examined in detail, a full-fledged design wing headed by an executive engineer and supported by assistant engineers and junior engineers is required.

"The seismic code for designing buildings comes into play in case of high-rise structures which have more than three storeys," says Avinash Mahajan, chief engineer, Public Works Department. Quake-resistant buildings need more steel reinforcements and bigger columns and beams. Mahajan maintains that all buildings and bridges were designed after taking the seismic factor into account.

However, the department has been guilty of not only constructing high-rise structures like the 10-storeyed High Court building, but also of using cantilevers in designs, which should be avoided at all costs in quake-prone areas. The most classic example is the High Court building itself which has long cantilevers on both sides. These cantilevers bring instability to the structure. Similarly, while the seismic code stresses on keeping the structures as light as possible, the department has been overloading the buildings by paving the floors, and even the outer walls, with marble, Kota stone and red sandstone.

The situation is worse in private buildings. The seismic factor is mostly not taken into account during designing. "Even in case of structures designed by architects, safety cannot be guaranteed," says Rakesh Mehta, a local architect, who has been designing buildings for the past two decades. A quake-resistant structure requires about 30 per cent more steel and cement, which adds to the cost.

However, ignorant about the technical nuances of the structural design, people tend to economise on the construction material. Moreover, the construction is actually carried out by petty illiterate contractors who neither have adequate technical knowledge nor the necessary construction machinery like concrete mixers and vibrators.

Besides, old structures, like the Gaiety Theatre, that are being protected as heritage buildings, could also collapse during an earthquake. To make the existing structures quake-resistant is not a practical proposition in view of the high cost involved.

The Gujarat disaster has woken up the government to the need for making quake-resistant features mandatory for all buildings, However, the move may have come a bit too late. Already much construction has taken place and most of the important towns have virtually become concrete jungles. In fact, construction activity has reached a saturation point in places like Shimla, Kulu-Manali and Dharamsala. Only recently, the government banned construction in some of these towns.

The engineers maintain that it will not be easy for the government to ensure construction of quake-resistant structures by amending building bylaws, particularly in view of its failure in enforcing the existing bylaws and checking the coming up of unauthorised constructions. The answer lies in creating awareness among people and evolving a number of standard structural designs to suit the requirement of the people. Moreover, proper training has to be imparted to contractors, masons and all other workmen connected with construction activity to ensure that safety measures like provision of seismic bands and proper detailing of joints to make the building quake-resistant become an integral part of building works.

At present there is no extension agency in the state for dissemination of knowhow and training the workmen. It is for this reason that no systematic effort has been made to introduce new materials to make the constructions safer.

It is not for the first time that the government has initiated a move to ensure construction of quake-resistant structures. A similar exercise was undertaken after the 1986 earthquake which caused widespread damage in and around Dharamsala. The Earthquake Engineering Department of Roorkee University had studied the impact of the tremor, which caused moderate to severe damage to about 35,000 houses. It had also prepared a comprehensive report which included suitable recommendations for new quake-resistant constructions, upgradation of existing buildings and measures for disaster mitigation in future. However, not much follow-up action was taken on the report.

One hopes that the Gujarat disaster will galvanise the government machinery into taking long-term steps to prevent loss of life and property in this quake-prone state.