pressuremeter or other magic instrument

[capablanca]

Telecom towers usually are overloaded with new antennae that increases the wind forces and reactions.Overturning of
the towers is one problem.The other is soil bearing stresses.For checking these last effects it is needed an in situ soil strenght evaluation that normally shall be done for many towers.Does anybody has experience in this problem;thus approx. evaluate the soil capacity using instruments such a pressuremeter or other magic? Does exists new generation technology for this?With electronic displays and so on.It seems not but
that is my question!

 

[BigH]

There are many means to determine or gain an appreciation of the ground - as most experienced geotechs would be able to advise. Some initial thoughts.

The actual tests to be run depend on (1) available equipment and drilling equipment (2) types of soils encountered (always best if you know likely substrata before mobilizing) (3) level of sophistication in analysis -how critical/how complex do you want to be (4) methods of analyses you will use. No sense putting rudimentary soils data into a sophisticated computer analysis; vice versa, no sense putting sophisticated in situ testing into rudimentary or back of envelope types of analyses.

I would consider the following:
SPT - especially in sands (correct to energy levels)
vane shears, field - in clays of firm consistency or less
piezo-cone: very nice; get a nice read computer readout
of data; very valuable.
dutch cone - the older version; tip and friction values
pressuremeter - could use self boring or the one put into
hole after boring.
Good quality undisturbed samples (then let DirtDoc1
advise of the testing!!)

For important towers; consider a lateral load test on an installed pile (assuming that you will use piles) - or, if the piles will be used in tension, a tension pile load test. These give large scale field values that are not as sensitive to size effects. Similarly, if using soil or rock anchors for guy wires, can do pull-out tests of anchors.

Get a good geotechnical consultant who has worked in the area or experienced in towers. He'll be able to provide you specific info to your problem. Money well spent.

Best of luck.

 

[Focht3]

I'd be surprised if the bearing capacity of a monopole communication tower is more critical than the lateral (wind, earthquake (if applicable)) loads. Unless you are using very long (tapered) precast concrete poles. What prompted this request?

If your geotechnical engineer can provide you with design guidelines for lateral loading, then surely he/she can do the same for bearing capacity. (Note: bearing capacity design is a lot easier than lateral design - from a geotechnical standpoint.)

If you are looking for a tool that will allow you to bypass hiring a geotechnical engineer, or you intend to dictate the tool(s) to be used in the geotechnical study, you're barking up the wrong tree. Hire a qualified, experienced geotechnical engineer - and let him choose the tools and test methods appropriate for the site and problem.