Need to propose new design to owner!!

[projectEST]

Hey all,

I need to propose to an owner, Turner Construction, a new design for a deep pier/footing that is originally seated on-top of rock.

Bear in mind that I'm a foundation contractor with a civil degree. Im not as well versed as I'd like to be due to the fact that I'm relatively new.


Basically, there are 3 footings near a railroad that seats on-top of rock(elevation 2) The water table kicks in around elevation 15. The soil is very unstable, i had one machine sink today and another had to pull it out. We can either set-up a comprehensive dewatering system and install cofferdams as our means to perform the work.

We dont want to do this, I propose that we install Mini-piles and create a pile cap as the new design.

Now do you recommend that I contact my engineer to create the design and then submit. Or shall I contact the owner first without a design.

We've dug test pits to confirm our beliefs of the water and soil structure.

The mini pile method will be slightly cheaper than the original design which of course is a plus.

Please shine your knowledge this way.

Thanks.

Joe
Project Engineer

 

[DaveAtkins]

Don't waste your company's money on a full blown design prior to getting everyone on the team to buy in. Just make sure that what you are stating, IN CONCEPT, is correct.

DaveAtkins

 

[csd72]

And if you claim anything regarding it being cheaper make sure it is correct. Probably basing your proposal on time savings may be a better option.

As it is bearing on rock, piles, with their smaller end areas will not be as strong as piers. You will probably need more of them.

Notify the engineer of your problems first, they may have a solution that you have'nt thought of. If you dont get any satisfaction there then contact the owner.

csd

 

[TDAA]

Talk with your boss first (if needed - perhaps to get different concepts or to CYA).
Talk with who you are contracted with second.

Explain the problem.
Provide alternatives.
Describe the benefits /drawback of the options (costs/time/constructability/performance)
Provide a recommendation for the alternatives.

Work with the team to implement the solution.

 

[DRC1]

Mini piles are a specialty. If you have a contractor in mind, I would review it with them and they should be able to get you a preliminary design and estimate. Remeber working around the railroad, he may need to consider restricted hours, work restrictions, additional submittals and worker safety training. In addition you may need to figure costs for supplying water, providing support, such as moving tools and materials, removing spoils and replacing contaminated ballast. Not that the minipiles are not a better alternative, just that some of these factors can sneak up on you if you are not careful.
I would clear the concept with your management and then present it to Turner. If they are good with it, you will probably have to pitch it to the railroad. You may want to bring your minipile contractor along to that meeting

Good Luck!

 

[projectEST]

Great responses thus far.

Our company has performed mini-pile jobs before, so creating the estimate is the easy part.

We are already working near the railroad ROW(right-of-way) so training, pre-cautions and other misc items have been taken care of.

We're currently putting a proposal together for the re-design. The owner will accept this design as long as the loading capacity will be equal to or greater than piers to rock.

Joe
Project Engineer

 

[csd72]

The structural engineer still needs to be made aware of this change. There may be consequences to the structural behaviour of the building above that you havent realized.

csd

 

[projectEST]

When i said owner, I shouldve said:

Owner, CM, Architect, Engineer, Structural contractor.

Joe
Project Engineer

 

[fattdad]

Where is the job, what is the surface elevation and how great are the loads acting on the pile cap? The instability of the ground surface will affect any/all construction equipment, so I'm not sure why that would render the use of driven piling more difficult.

My concern with mini-piles in wet and soft soils has to do with the quality control on maintaining the diameter. I'd not rule out driven piling (h-piles with rock shoes) if you are just talking about a 30 ft length.

Then again, maybe I don't have the full story. . . .

f-d

¡papá gordo ain’t no madre flaca!