Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in
  • Congratulations waross on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

Disturbing bedding of existing RCP

Status
Not open for further replies.
oengineer

oengineer

Structural
Apr 25, 2011
705
US
I am working on a project were we are having to provide a foundation for a proposed manhole which has an existing RCP going through it (see image):

prop_mh_bs1msn.jpg


My concern is the width of the bedding for the existing RCP. With the foundations encroaching upon the foundation bedding, what is the acceptable bedding width to be maintained for the existing RCP?

The foundation will still need to be able to support the manhole above it. Assume a 48" dia Wall C (wall thickness 5.75") existing RCP.

The following image is from the Design Data 9 - Standard Installations and Bedding Factors for the Indirect Design Method:

design_data_9_dedjxv.jpg


Comments/suggestion are appreciated.
 
Replies continue below

Recommended for you

Sort by date Sort by votes
Is the "D[sub]o[/sub]/3" sufficient for the existing RCP bedding width or does a greater width need to be maintained?
 
Upvote 0 Downvote
To clarify, what is preventing you from temporary supporting the pipe and installing the manhole in a standard fashion? This is a typical method for the manhole over an existing pipe.

Screenshot_l5b0yn.png
 
Upvote 0 Downvote
I have been told that the pipe is old/delicate and that they would prefer to leave the existing pipe in place while building a foundation for the manhole.
 
Upvote 0 Downvote
The standard detail above is for leaving the existing pipe in place. The practice is to let the pipe span the excavation (provide temporary support as needed) and place the base slab under the existing pipe then install the doghouse section of the manhole. IMHO if the level of concern over the pipe integrity is so high that you can not temporarily support it then it probably means the pipe should be replaced.
 
Upvote 0 Downvote
Status
Not open for further replies.

Similar threads

Structural Matt
  • Question
Capacity of Existing Waffle Slab 2
Replies
8
Views
146
Structural Matt
Structural Matt
shacked
  • Locked
  • Question
Analysis of existing and new framing
Replies
5
Views
94
shacked
shacked
TBCENG
  • Locked
  • Question
Repair of Existing Dock
Replies
5
Views
45
LittleInch
LittleInch
mats12
  • Question
Reinforcing existing timber beam
Replies
6
Views
770
north_man
north_man
structuralengr89
  • Question
Framing a New Roof on Top of an Existing PEMB Roof 5
Replies
7
Views
167
bones206
bones206

Part and Inventory Search

Sponsor

Back
Top