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[dcrai]

Dear Participants,

During the last few days of the e-conference some very insightful comments
and useful suggestions for improvement have come forth. I am really
thankful to all the discussers for taking time to read the long document
and post their views on the e-conference.

In general, most comments are directed to the lack of adequate details in
strengthening/retrofitting portion of the draft code. This was very much
expected and we were very much aware of this discrepancy while drafting
the code. It is primarily due to the non-availability of the reliable
code-like provisions for most of the strengthening options. As a result,
not only in this draft code but in other international codes also, very
little is mentioned about the specifics. Often the reference to specialist
literature is sought.

Such codes for existing buildings lay most of the emphasis on the
systematic evaluation of the available resistance of the structure and
identification of deficiencies and their effect. A study of many
strengthening projects indicates that a variety of strengthening options
are generally employed to correct different types of deficiencies.
Considering vast differences across various buildings, it is not prudent
to specify a unique strengthening scheme. Therefore, individual
description of strengthening option appears to be more logical and it is
left to the designer/engineer to combine them to develop a strengthening
solution for each building project. In other words, the tailor-made
approach is preferred over a readymade, one-fits-all approach.

Further, it has been rightly pointed out that many strengthening
alternatives have not been included; for example, fibre-wrapping for
column jacketing. The reason is once again the lack of code-like
provisions. If the Indian design community feels that this is the most
attractive option, then the efforts should be taken up to develop a
consistent and reliable design methodology.

Field test are encouraged by the draft code for the reliable estimate of
the available capacity/strength of the existing structure, as it has
direct bearing on the future strengthening costs. In-place shear and
deformability tests have been recently developed for reliable prediction
of strength/stiffness of the existing masonry. Only with more tests,
uncertainty about the strength/capacity and, therefore, subjectivity
regarding the value of ‘mk’ can be reduced. Suggestion to expand the
section on field tests is certainly most welcome. Also, as suggested, a
general form or check-list can be prepared for collecting information
about the building.

I once gain thank you for your keen participation and useful discussion.

Durgesh Rai

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