Tuesday, November 20, 2007

Re: Expansion Joint in Tunnel

Sirs,
 
        I agree with Bill's assessment that expansion and shrinkage will probably not be a problem and that EXPANSION joints are probably not required.
 
        Never-the-less, the use of large raft foundations suggests to me that differential settlements in the vertical direction are very likely.  This may require construction joints designed to accommodate differential movements between the various structures.  I would suggest that you have a discussion with the geotechnical engineer familiar with your site.
 
        As an aside, the differential cost of expansion joints is relatively inexpensive for a project of the magnitude that you describe; such problems can safely be left to the design stage for solution.  I think that the presence of a high water table on the project site presents a much much more expensive problem than expansion joints.  I would personally not even think of presenting a proposal for this project without a comprehensive and detailed plan for dealing with the water problem.  You could easily spend hundreds of times the cost of construction joints in dealing with the water problem.
 
        Good luck with the project.
 
Regards,
 
H. Daryl Richardson
----- Original Message -----
Sent: Tuesday, November 20, 2007 12:00 AM
Subject: Expansion Joint in Tunnel

Dear Sefiant,

 

We are having 50m long tunnel connected between two buildings at raft foundation level. Building sizes are approximately 50m x 50m and building has one basement hence tunnel is connected between basements and entirely buried in soil.   And water table is 3m above bottom of tunnel as per geotechnical report.   We are not providing any Expansion Joint, is it acceptable or not?

 

Also We are having underground car parking structure approximately 500m long, 60m wide and top of roof slab is 1.5m below ground level. We have not provided any expansion joint in raft but expansion joint is provided every 50m c/c above raft.  Request you to comment on the proposal whether it is ok or not?

 

Can anybody having the design experiences share some knowledge?

 

Thanks in advance.

 

Regards,

S.Srinivasan,

J.Surendra

 


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