Delhi NCR under severe Seismic Zone

Seismic Zone_indianbureaucracyv
Seismic Zone_indianbureaucracy

As per Bureau of Indian Standards [IS-1893 (Part- 1): 2002], based on the past seismic history, Delhi lies in Zone-IV that has fairly high seismic city where the general occurrence of earthquakes is of 5-6 magnitude and occasionally of higher magnitude. Delhi lies among the high-risk areas.

A state-of-the-art 16 station Seismic Telemetry System is already in operation by National Centre for Seismology (NCS) to detect and locate earthquakes in and around Delhi.  The data generated by this network is useful in understanding the changing profile of seismicity and seismotectonics of the Region.  NCS has also completed the seismic microzonation of Delhi-NCR on 1:10,000 scale, that provides additional inputs relating to the effects of the underlying soil in the assessment of damage potential. These seismic microzonation maps have become useful in land use planning and formulation of site specific design and construction criteria for the buildings and structures towards minimizing the damage to property and loss of life caused by earthquakes.

In a pilot mode, studies have been taken up for Delhi region through rapid visual screening (RVS) of assessing the structural safety of buildings due to existing complex socio cultural and built environment encompassing vide range of dwelling units from non engineered units with traditional skill to the most modern buildings. Essentially RVS procedure considers different building types that are most commonly found in India. Whereas the building categories considered for the purpose includes Type A, Type B, Type C and Type X categories as detailed in Annexure-1.

By imparting professional training to the Engineers of the civic bodies, Delhi Government is enhancing the technical capabilities of field engineering wings to survey potentially weak buildings. Guidelines for improving Earthquake Resistance of Low Strength Masonry Buildings (IS 13828:1993) that covers the special features of design and construction for improving earthquake resistance of buildings of low-strength masonry are already in force to supplement these efforts.

Guidelines have also been published by the Bureau of Indian Standards (BIS), Building Materials & Technology Promotion Council (BMTPC) and Housing and Urban Development Corporation (HUDCO) etc. for the design and construction of earthquake resistant structures to minimize the loss of life and damage to property caused by earthquakes (Annexure II). These guidelines are in wide circulation amongst the public and the administrative authorities responsible for the design and construction of earthquake resistant structures in earthquake prone areas.

Ministry of Home Affairs has taken steps to see that all new buildings constructed under various National and State schemes should be made earthquake resistant (as per the Bureau of Indian Standards detailed at Annexure-III) in the first instant so that no new additions to the stock of existing unsafe buildings are made.

Central Public Works Department (CPWD) has prepared a Handbook of Siesmic Retrofit of Buildings for existing buildings that do not meet the seismic strength requirement.

This was stated by the Union Minister for Science & Technology and Earth Sciences, Dr. Harsh Vardhan in a reply to a question in the Rajya Sabha today.

Annexure-I

Building Category

Type·A Rural structures bamboo reinforced Biomass wall cladding, thatched/CI Sheet roof, un·burnt brick house, Assam Type Houses in timber frame.
Type·B Brick Masonry Wall 6″X6″ to 10″X10″ Corner columns with lintel bend and tie, timber trussed CI sheet roof, buildings of the large block and prefabricated type, half-timbered structures, building in natural hewn stone.
Type·C Reinforced Concrete Building- Engineered & Non-Engineered With beam, column & slab construction, well built wooden structures.
Type·X: Other types not covered in A, B,C.

RDS/ss

Annexure-II

Brochures and Guidelines published by Housing and Urban Development Corporation (HUDCO) & Building Materials & Technology Promotion Council (BMTPC)  for construction and retrofitting of buildings:

  1. Brochure for mitigating damage to dwellings (in English, Hindi, Tamil, Telugu, Oriya and Bengali by HUDCO).
  2. Brochures on house construction in Jabalpur and Chamoli earthquake-affected areas (in Hindi, by HUDCO).
  3. Retrofitting of stone houses in Marathwada area of Maharashtra, (BMTPC), 1994.
  4. Guidelines for repair, strengthening and reconstruction of houses damaged in the 30 September, 1993 earthquake in Maharashtra (Government of    Maharashtra), 1994.
  5. Earthquake and Building, A guidebook to understand the relationship between the two, (TARU), 1994.
  6. Build Your Home with Earthquake Protection, (BMTPC), 1995.
  7. Guidelines 1 – Earthquake-resistant construction of houses in Jabalpur earthquake-affected areas (in Hindi, English, BMTPC), 1997.
  8. Guidelines 2 – Repair and retrofitting of damaged houses in Jabalpur earthquake-affected areas (in Hindi, English, BMTPC), 1997.
  9. Guidelines 1 – Visual Damage Identification for Chamoli earthquake-affected areas of Uttar Pradesh (in Hindi, English, BMTPC), 1999.
  10. Guidelines 2 – Repair and retrofitting of damaged houses in Chamoli earthquake-affected areas of Uttar Pradesh (in Hindi, English, BMTPC), 1999.
  11. Guidelines 3 – Reconstruction and New Construction of Buildings in Chamoli earthquake-affected areas of Uttar Pradesh (in Hindi, English, BMTPC), 1999.

Annexure-III

LIST OF RELEVANT INDIAN STANDARDS ON EARTHQUAKE RESISTANT DESIGN AND CONSTRUCTION

S.No. IS No. Title
*1 IS 1893: 1984 Criteria for earthquake resistant design of Structures
2 IS 1893(Part 1): 2002 Criteria for earthquake resistant design of structures: Part 1 General Provisions and buildings.
*3 IS 1893(Part 4) : 2005 Criteria for earthquake resistant design of Structures: Part 4 Industrial structures including stack like structures.
*4

IS 436:1993

Code of practice for earthquake resistant design and construction of buildings5

IS 4991:1968

Criteria for blast resistant design of structures for explosions above ground6

IS 6922:1973Criteria for safety and design of structures subject to underground blasts7IS 13827: 1993Improving earthquake resistance of earthen building – Guidelines8

IS 13828:1993Improving earthquake resistance of low strength masonry building – Guidelines9IS 13920:1993

Ductile detailing of reinforced concrete structures subjected to seismic forces- code of practice.10

IS 13935: 2009Seismic evaluation repair and strengthening of masonry buildings – Guidelines

* Under Revision

FINALISED DRAFTS UNDER PRINT

S.No. DOC Number Title
1

DOC.CED 39 (7231)Criteria for Earthquake Resistant Design of Structures; Part Liquid Retaining Tanks2

DOC.CED 39 (7620)Seismic Evaluation and Strengthening of Exiting Reinforced Concrete Building – Guidelines.3

DOC.CED 39 (7620)Earthquake Resistant Design and Construction of Building – Code of Practice (Third revision of IS 4326)4

DOC.CED 39 (7739)

Draft Indian Standards criteria for Earthquake Resistant Design of Structures: Part 3 Bridges and Retaining Walls.

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