sewerage, storm water and irrigation network

Hi Sunil

It depends on your work pattern.

Are you putting the manholes in first and connecting the pipes or laying the pipes and coming back to straddle the manholes.

Either way you will need a small cascade for each manhole detailing the sheet piles with soft logic (resource based) linking the switch of the piles between manholes.

If you are also using sheet piles to support the trenches treat that as a seperate issue with its own dedicated piling reource.

Rafael and Vladimir will tell you resource level your pile usage resource but then you will lose control of your network.

If you have enough surrounding space consider a cut - batter - backfill method.

Best regards

Mike Testro

Hi Mike,

Thank you for your quick response, our pattern of work is laying pipes first then construction of Manhole (In deeper areas).

Pipe laying in deep areas are by the method of microtunneling and prior to micro tunneling we have to do

sheet piling in the manhole area that occupies the TBM. Also manhole areas ranging 2.5 to 14m depth are

covering with sheet piles (as there are no pipe trenches in these area, only tunneling for pipe laying). All the deeper

manhole areas sheet piles are there, my question is how effectively we can make a schedule to do the re-using of sheet piles.

For every 40m -to 50m intervals there are manholes.

With Regards,

Sunil.

Hi Sunil

Now everything depends on how flexible your software is.

P6 is not ideal for this type of linear project (my position is that P6 is not suitable for ANY project).

In a 14 metre deep hole the sheet piles will need to be at least 20m long.

This will require the strongest grade of sheet piles which come in standard lengths of 9m.

Using the "excavate & push method" of pile installation there will be the need for at least one weld for installation and a cut on removal.

On a spreadsheet calculate the number of piles for each type of manhole using standard 9 m lengths - this will give you the total pile deployment.

Now ascertain the total number of piles you are going to purchase and that will show you the number of manholes that can be piled at any one time - add a 20% contingency for spoilt pile sheets.

If you have enough pile sheets to install (say) 5 manholes at any one time then set up a resource named "Pile Set 1" through to "Pile Set 5"

Apply resource Pile Set 1 to manhole 1 - 6 - 11 - 16 and so on.

Pile set 2 will be allocated to manhole 2 - 7 - 12 - 17 etc

Now you can link all manholes with each Pile Set in sequence to show optimum re use.

I would imagine that these "Manholes" are chambers for Air Release Valves and/or Drain Down Points at peaks and troughs allong the trench.

If that is the case the "Manholes" are best placed after the micro tunnelling drive has stopped in that section.

Best regards

Mike Testro

Hi Mike,

Thank you for your timely reply. In this type of project we have to set a critical path based on these

piling schedule and manhole construction. Hope this schedule will work out fine. Which software is

your preference for this type of projects and why are you prefering that ?

Best Regards,

Sunil.

Hi Sunil

Linear projects work best with a dedicated Time - Distance software such as Tilos.

I achieve similar results with Asta Power Project in "Task per Line" mode where you can generate a "Line of Balance" view.

Another method you might consider is to use an adaptation of the old "Hong Kong Piling" method where precast concrete circular manhole rings are laid on a steel ring base that sinks into the ground as the inside is excavated and other rings are piled on top.

This would have to be done before the pipe line is in place but it is very quick and cheap.

Best regards

Mike Testro

Mike,

when resources are limited time-distanse software is not efficient though Time-Location charts are very useful.

Hi Vladimir ,

In this type of linear projects  the time location plan will be more effective compared to other plan,

what i understood from your statement is that we have to divide entire project into zones or areas then proceed accordingly is it?

Expecting your comments.

Regards,

Sunil.

Hi Sunil,

time-location chart is certainly very useful presentation of the project schedule.

But the schedule shall be calculated taking into account all existing constraints like limited resources, supply restrictions, space restrictions, resource calendars, etc. So it is necessary to create schedule model, not just draw the lines. The result of resource constrained scheduling may be presented as time-location chart, Gantt Chart, Network diagram, etc.

Regards,

Vladimir

Hi Sunil

Every linear project has to broken down into sections for programming.

In your case the length that can be micro tunneled in one push.

Best regards

Mike Testro

Hi Mike,

As you commented , we are proceeding in area wise sections also microtunneling zones are seperated with sheet piling works .

Other areas having depth less than 5m comes under cutting trench and laying pipes logic following.

Best Regards,

Sunil.