Geo-Structural Shoring Design

[Geotech_Pavement]

Hi. Is there anyone here who does or has done before both geotechnical (investigation report, recommendations, pressure distribution, passive resistance, etc)and the structural aspects (draw the force diagram and design the structural member)for shoring design ?

I am a geotechnical engineer and interested to get into the structural design aspect of shoring. It seems very interesting and also lucrative since it is so specialized and high risk. I practice in California, and the norm in the industry here is to have a specialized small structural engineering company doing the shoring design. I have never seen the geotechnical engineers do the structural shoring design.

I want some tips from experienced structural shoring designers for advice to get into the design and business. Is this something I can learn on my own ?

I actually did my undergraduate degree with strong emphasis in structural engineering, so the concepts are not foreign to me and I have a strong engineering background.

I really appreciate your input.

Thanks

Alex

 

[DaveAtkins]

With a good textbook, you can learn the basics of shoring design (sheet piles, walers, tie backs, etc.). However, it would be better if you had a mentor, or perhaps an independent engineering firm, to review your calculations.

DaveAtkins

 

[EireChch]

Geotechnical firms regularly do the structural design of shoring systems. Its very common.

 

[Geotech_Pavement]

So what softwares do geotechnical firms use on a regular to perform structural design of shoring?

PyWall by Ensoft?

 

[EireChch]

Things like DeepEx are used un the US I think. but the US guys will need to advise.

In the UK we use Oasys software, GRETA, ADSEC etc.

Or many just use excel spreadsheets. The calculations are very straight forward so structural software are often not needed. You definitely need geotech software to extract your bending moments, shear force, prop loads etc.

 

[DaveAtkins]

For cantilever and tied sheet pile walls, cofferdams, and soldier pile and lagging walls, I use SPW911, a program developed by PileBuck.

DaveAtkins

 

[MTNClimber]

On the East Coast, it is more common to do both traditional geotechnical and temporary/permanent shoring design, although not everyone does both. When I worked in Colorado, the shoring design was considered “for structural engineers only.” Geotechnical engineers didn’t want to touch it with a 10’ pole.

You can learn about the fundamentals on your own. There are plenty of free online resources. US Steel Sheetpile manual was my bible in the early days. FHWA has some good guidance on soil nails. You’ll need a solid background in steel and concrete design. Timber design pops in occasionally on smaller applications.

We use SupportIT and CT Shoring for sheet piles and soldier pile walls. We prefer Snail for soil nails over the rest (and we have tried the rest). For the record, are not a fan of DeepEx’s software.

 

[MTSOE]

There are many free online (American) resources which can give you good insight to shoring design. These include, but are not limited to:
-California Trenching and Shoring Manual
-NAVFAC Design Manuals 7.1 & 7.2
-FHWA Lateral Support Systems and Underpinning
-FHWA Geotechnical Circular No 4-Ground Anchors and Anchored Systems
-FHWA Design Manual for Permanent Ground Anchor Walls
-USS Steel Sheet Pile Design Manual

Of course there are many aspects of geostructural design which work very well in practice but would never appear in a manual. Opinions will differ from firm to firm.

I know plenty of geostructural designers who started with geotechnical backgrounds, and I know designers who started with structural backgrounds. People from both backgrounds have been very successful in the industry. Perhaps more important than either of these is an understanding of the construction techniques used to install the structures you would design. The techniques often influence/dictate the loads, boundary conditions, and properties you assign to your structures.

Good luck.

 

[PEinc]

When doing geo-structural design for a contractor, it is important to know the contractor's abilities and experience. Just because you can design it, that doesn't mean the contractor is able to safely build it. Designing for incompetent contractors is a fast way to get in big trouble.

http://www.PeirceEngineering.com

 

[Smoulder]

@PEinc Have you been bitten a time or two?

 

[EireChch]

PEinc - that can be a difficult thing to assess. Especially if you are in the early stages of working with a contractor! but valid point nonetheless

 

[PEinc]

Smoulder, we are very careful about doing work for companies that we do not know their capabilities. The bigger problem jobs are the smaller underpinning jobs. Too many contractors claim to be underpinning experts but are really clueless - clueless but usually lucky! YouTube is full of incorrect, dangerous underpinning videos. We try to hold the hands of the less experienced, sheeting and underpinning contractors or we refer them to more experienced contractors. We visit job sites and talk to the field supervisors. Most don't hesitate to call us if they have a question or problem. A geo-structural designer who has proper construction experience can usually foresee and help the contractors avoid problems.

http://www.PeirceEngineering.com

 

[SlideRuleEra]

Contractors who (successfully) perform this type work tend to accumulate an inventory of assorted structural steel shapes and sizes. Keep an open mind when selecting members. For example, your engineering calcs may indicate that a certain W10 (which have to be purchased or rented) is the best choice... the contractor may have plenty of "free" HP12s that will work nicely, perhaps with some change in your design.

Just because an inventory member has been used many times before (getting "banged-up" along the way), don't discount using it again... down rate allowable stress to account for it not being new.

When designing, remember that how the temporary structure is taken down is just as important has how it is erected. The contractor will NOT want to go in with a cutting torch and slice-up nice temporary structural steel that he could have reused another time.