The Ministry of Urban Development, Government of India, has issued amended bylaws for the Delhi area to ensure the coming up of earthquake-resistant buildings. The incorporation of safety measures will be the responsibility of owners.
The amended bylaws are to serve as the model for the states which have been directed to enact similar bylaws. It has been made mandatory to provide a certificate along with building plans and an undertaking that the plans submitted for approval "satisfy the requirements as stipulated by the NBC (National Building Code).
The certificate, as also the building plans, will have to carry the signatures of the building owner, the architect and that of a structural engineer. A similar certificate will have to be furnished at the time of obtaining the completion certificate for the building that it has been built strictly according to the plans and design approved.
So, a person desiring to build a house will have to be fully aware as to what constitutes a safe design for an earthquake-resistant building. This write-up is an attempt to list the common pitfalls which make a building vulnerable to earthquakes.
An interesting publication on the subject has been brought out by the Indian Standards Institute (renamed the Bureau of Indian Standards), New Delhi, entitled "Earthquake-Resistant Design and Construction of Buildings". Several expert agencies have worked together in bringing out this book. The various recommendations listed in it have been verified experimentally on models tested on the "shake-tables tests".
The earthquake force imparted to a building is a function of mass. So, the building should be designed as light as possible, consistent with structural safety and functional requirements. Thus the roof and the upper storeys of the building in particular should be designed in this manner. The different components of the building should be tied together in such a manner that it acts as one unit. The concrete slabs should be rigidly connected or integrally cast with the support beams.
Additions and alterations to the building should be accompanied by the provisions of "separation" of the "crumple" section between the new and the existing structure.
Cantilever or projected parts should be avoided as far as possible. But where necessary such a construction should be properly reinforced and fully tied to the main structure and adequately designed. A prefabricated construction has been found, after the American earthquake of 1988, to be prone to collapse due to the post-tremor impact.
Ceiling plaster should be avoided as far as possible, but where necessary, such a plaster should be kept as thin as possible. Suspended ceiling should not be provided as such a construction is most prone to falling down during tremors. Where provided, suspended ceiling sections should be adequately framed and secured.
In order to minimise "torsion and stress concentration", a building should have a simple rectangular plan, and should be symmetrical, both with respect to the mass and the rigidity of the structure. The length of the rectangular section should be kept not more than three times its width.
The centre of rigidity is defined as the point where a lateral force, if applied, would produce equal deflections of its components as at any one level in any particular direction.
If the symmetry of the structure is not possible in the plan, elevation or the mass, provision should made for torsion and other effects due to an earthquake in the structural design, or parts of different rigidities should be "separated through the crumple section".
No structure should be founded on loose soil (such as fine sand, silt). In case loose fine soil or expansive clay soil cannot be avoided, we should either provide a "raft foundation" or a "pile foundation" with the piles transferring the load to the firm soil. The other option available is the "foundation improvement" by either "sand piling" or by "vibro-compaction" of the loose soil.
All the "individual footings", or the "pile caps" where adopted in soft soil, should be connected by reinforced concrete ties extending in at least two directions at right angles to each other.
For buildings with a basement, the ties be placed at the level of the basement floor. These ties should be designed to carry the load of the panel walls also if located on them.
Such ties will not be needed where the structural floor connects the columns at or below the plinth level. These ties should be designed to "tension" and "compression" loads, in addition to the axial load not less than the earthquake force acting on the heaviest column connected. While working out the "buckling strength" of the ties, the lateral support provided by the soil should be taken into account.
Where necessary a complete separation of different parts of the building should be made except below the plinth level.
The foundations have to be equipped to face the lateral force whose magnitude may be found from the "design seismic coefficient" or from dynamic model tests on shaking-tables.
It may be mentioned that the commonly adopted individual footings have virtually no strength to meet the lateral forces. But if the individual footings are tied together with structural members of adequate strength to transmit tension or compression forces, from one footing to the group, the chances of survival increase.
Basement walls provide a "thrust area" which reduces the lateral force required to be carried by the foundations. Raft foundations located on the well-compacted soil require less rigid lateral support to ensure greater "damping" and absorb a greater amount of energy.
Doors and windows in the walls reduce their lateral load resistance and hence these should preferably be small and centrally located. The top of all openings in any one storey should be at the same level so that a continuous band is provided.
Band of reinforced concrete or reinforced brick work, provided in the walls is to tie together and to impart horizontal bending strength, which is a desirable feature against earthquake forces. One such band should be located near the plinth level and other just below the roof. Such bands provide the overall integrity of the building so that all the walls act simultaneously together under the earthquake force which then get distributed on the walls.
The bands at the plinth level, the lintel level and the roof level should be joined by the vertical steel (MS bar of 12 mm diametre for a single-storey house, and an 18 mm bar located at the junction of the walls is considered adequate.
Le Corbusier design show opens in Liverpool
Exhibition will celebrate architect's multidisciplinary approach to design
An exhibition of le Corbusier's work will open on Tuesday in Liverpool as part of the city's European Capital of Culture events.
The show includes models of the architect's most influential buildings, from the arts-and-crafts houses in his native Switzerland to the Ronchamp chapel and his designs for Chandigarh in India.
It will also explore Le Corbusier's multidisciplinary approach to design, combining art and film with urban planning and architecture.
The exhibition will be the first ever staged in the crypt of Liverpool's Roman Catholic cathedral. It will remain there until 18 January, then move to another UK location – the Barbican Arts Centre in London, where it will be on view from 19 February to 24 May.
An exhibition of le Corbusier's work will open on Tuesday in Liverpool as part of the city's European Capital of Culture events.
The show includes models of the architect's most influential buildings, from the arts-and-crafts houses in his native Switzerland to the Ronchamp chapel and his designs for Chandigarh in India.
It will also explore Le Corbusier's multidisciplinary approach to design, combining art and film with urban planning and architecture.
The exhibition will be the first ever staged in the crypt of Liverpool's Roman Catholic cathedral. It will remain there until 18 January, then move to another UK location – the Barbican Arts Centre in London, where it will be on view from 19 February to 24 May.
Construction World Awards India's Top Builders, Architects
The 3rd Construction World Architect & Builders Awards were distributed by the Governor of Maharashtra to recognize exceptional work done by Architects and Builders in various aspects of infrastructure and real estate industry.
The awards for the first time used the perception mapping process and conducted an exhaustive survey to select the winners.
The winners included Niranjan Hiranandani, Managing Director of Hiranandani Developers, Milind Korde, Managing Director of Godrej Properties, J C Sharma, Managing Director of Shobha Developers, architects Hafeez Contractor, Noshir Talati, Abhin Alimchandani and I M Kadri among others.
The awards were organized by ASAPP Media Information Group and supported Builders Association of India (BAI) and Maharashtra Chamber of Housing Industry (MCHI) and represented by national and international firms.
LIST OF WINNERS - ARCHITECTS (Alphabetically)
1. Abhin Alimchandani - Stup Design Forum
2. Arunjot Singh Bhalla - RSP Architects Planners & Engineers (India) Pvt Ltd.
3. Hafeez Contractor - Architect Hafeez Contractor
4. I M Kadri - Kadri Consultants Pvt. Ltd.
5. Kamal Malik - Kamal Malik Architect
6. Noshir Talati - Talati & Panthaky Associates Pvt. Ltd.
7. Prem Nath - Prem Nath & Associates
8. Raja Aederi - Raja Aederi Architect
9. Sanjay Puri - Sanjay Puri Architect Pvt. Ltd.
10. Shahrukh Mistry - Mistry Architects
LIST OF WINNERS - BUILDERS (Alphabetically)
1. Brigade Group - M. R. Jaishankar, Managing Director
2. DLF Group - Rajiv Singh, Vice Chairman
3. Godrej Properties - Milind Korde, Managing Director
4. Hiranandani Developers - Niranjan Hiranandani, Managing Director
5. K. Raheja Corp - C. L. Raheja, Chairman
6. K Raheja Universal - Ashish Raheja, Managing Director
7. Kalpataru Constructions - Mofatraj Munot, Chairman
8. Shapoorji Pallonji & Co. - Cyrus Mistry, Managing Director
9. Sobha Developers - P N C Menon, Chairman
10. Unitech - Sanjay Chandra, Managing Director
The awards for the first time used the perception mapping process and conducted an exhaustive survey to select the winners.
The winners included Niranjan Hiranandani, Managing Director of Hiranandani Developers, Milind Korde, Managing Director of Godrej Properties, J C Sharma, Managing Director of Shobha Developers, architects Hafeez Contractor, Noshir Talati, Abhin Alimchandani and I M Kadri among others.
The awards were organized by ASAPP Media Information Group and supported Builders Association of India (BAI) and Maharashtra Chamber of Housing Industry (MCHI) and represented by national and international firms.
LIST OF WINNERS - ARCHITECTS (Alphabetically)
1. Abhin Alimchandani - Stup Design Forum
2. Arunjot Singh Bhalla - RSP Architects Planners & Engineers (India) Pvt Ltd.
3. Hafeez Contractor - Architect Hafeez Contractor
4. I M Kadri - Kadri Consultants Pvt. Ltd.
5. Kamal Malik - Kamal Malik Architect
6. Noshir Talati - Talati & Panthaky Associates Pvt. Ltd.
7. Prem Nath - Prem Nath & Associates
8. Raja Aederi - Raja Aederi Architect
9. Sanjay Puri - Sanjay Puri Architect Pvt. Ltd.
10. Shahrukh Mistry - Mistry Architects
LIST OF WINNERS - BUILDERS (Alphabetically)
1. Brigade Group - M. R. Jaishankar, Managing Director
2. DLF Group - Rajiv Singh, Vice Chairman
3. Godrej Properties - Milind Korde, Managing Director
4. Hiranandani Developers - Niranjan Hiranandani, Managing Director
5. K. Raheja Corp - C. L. Raheja, Chairman
6. K Raheja Universal - Ashish Raheja, Managing Director
7. Kalpataru Constructions - Mofatraj Munot, Chairman
8. Shapoorji Pallonji & Co. - Cyrus Mistry, Managing Director
9. Sobha Developers - P N C Menon, Chairman
10. Unitech - Sanjay Chandra, Managing Director
Subscribe to:
Posts (Atom)