Civil Engineering Association

Indian Standard SEISMIC EVALUATION AND STRENGTHENING OF EXISTING REINFORCED CONCRETE BUILDINGS — GUIDELINES

This Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by the Earthquake
Engineering Sectional Committee had been approved by the Civil Engineering Division Council.
This standard is intended to reduce the risk of death and injury that may result from the damaging effects of
earthquake on building which predate the current seismic codes [IS 1893 (Part 1) : 2002 ‘Criteria for earthquake
resistant design of structures: Part 1 General provisions and buildings’, IS 4326 : 1993 ‘Code of practice for
earthquake resistant design and construction of buildings’ and IS 13920 : 1993 ‘Ductile detailing of reinforced
concrete structures subjected to seismic forces — Code of practice’] or have not been designed for earthquake
forces.
This standard describes a set of key steps and procedures for the assessment of the expected seismic performance
of existing building in the event of a design level earthquake and where found necessary, strengthening of existing
structural systems and elements for improved seismic performance.
Seismic forces for evaluation criteria of existing buildings are different from those meant for the design of new
buildings. Appropriate modifications are made to address the issues of reduced serviceable life and acceptable
risk for higher importance. Further, to account for uncertainty in the reliability of available information about the
existing structure and the condition of structure components, strength calculations need to be suitably modified.
For deficient buildings, a broad outline for the design seismic strengthening measures has been developed and
the interface with current design codes in general terms has been identified.
In the formulation of this standard, assistance has been derived from the following publications: