The requisite to increase the capacity of an existing building as per safety policy for earthquake proof buildings, to survive against the seismic forces rises typically from the indication of the caused damage & bad performance during an earthquake. It can also arise from computations or by evaluations with some similar buildings that have been damaged at other spots. In the first case, the landlord can be relatively convinced easily for taking up some earthquake protection actions, for improving the strength of the building. Whereas in the second case residents that have much more stringent day-to-day needs are generally hesitant to spend money for improvement of seismic safety as a part ofÂ earthquake preparedness.
The hurdles during repairs, restoration & seismic strengthening of buildings are concisely listed below:
(i) Before the occurrence of a likely earthquake, the essential strengthening of seismically weak buildings is to be identified by a survey & examination of the structures.
(ii) Just after a destructive earthquake, emergency repairs & temporary supports are to be conceded so that hazardously standing buildings may not fall during aftershocks & the less damaged ones could be quickly brought back into routine.
(iii) The actual repair & strengthening difficulties are faced at the stage once things start settling down, after the earthquake. At this stage difference has to be made in the type of action required, that is, repairs, restoration & strengthening, since the cost, time & skill required for them may differ.
Strengthening of existing masonry (Small cracks)
Large cracks & crushed concrete
Strengthening RC Members
Strengthening an arched opening in masonry wall
Strengthening with wire mesh & mortar
Strengthening of Foundations
Connection of new and old brick walls (T-junction) & Connection of new brick wall with existing stone wall