Stiff Pilecap + Pile reactions

[mustruct]

Hello!

I am trying to do hand check reactions of what STRAP gave me. But its a 3D solid model and I am finding hard time to get reactions by hand because it involves huge pile cap stiffness too. Can anyone throw some light on how it has to be done?

Really appreciate your time.
Attached: Pile cap, loads and dimensions.
All dimensions are in millimeter.

Thanks,

 

[ron9876]

P/n +/- M/S

 

[oneintheeye]

not sure what your trying to determine, is it pile loads? If so I typically use strap by using a flat plate and springs at the pile locations. This always confirms with hand calcs. Be careful on the spring value you take and don't make it to flexible. Also be careful that if you have horizontal loads that you either convert this to an equivilent moment (H X depth of cap) or use a 3D model.

 

[abusementpark]

There is a hand method for an elastic distribution of loads on a RIGID cap to RIGID pile supports. See the link below.

http://www.ce-ref.com/pile_cap.htm

 

[asixth]

Have the two loads of 2475kN been positioned on the pile to take into account? (i.e. load position away from the centroid of the pile cap).

 

[hokie66]

Why are the piles arranged in that fashion? It looks to me like practically all the load will go down the 10 battered piles.

 

[mustruct]

Thanks guys, i was now able to check the results from my 3D strap model and its is precise.

Really appreciate.

 

[mustruct]

By the by, if anyone interested to see the 3D result from strap and hand check let me know i can post it here..

 

[oneintheeye]

yes i would only because this is not how I normally do it.

 

[CTW]

I'm curious like Hokie66, why are the piles arranged that way?

 

[mustruct]

There you go guys...

Those are batter pile...A pile driven at an inclination to the vertical to provide resistance to horizontal forces... because its an abutment for one of the bridge..

Thanks,

 

[CTW]

I guess I should have posed my question differently. What was the reason for including the interior or middle set of battered piles versus not using that interior set and battering the vertical piles shown?

I don't do a lot of pile design but the ones I have been involved with used battered piles on opposing sides of the cap.

Just curious. I enjoy learing from others why they chose to do things certain ways.

 

[hokie66]

My query about the arrangement was different from CTW's. I was wondering what is the purpose of the section with the vertical piles. There is no load on that section, and it only serves to make the distribution of pile loading irregular. Without the four piles, all piles would see essentially the same load, about 500 kN.

 

[mustruct]

Hello!

Its an abutment and i just considered only one loading to cross-check the strap results with my hand calculations. Actually I have loadings in all directions.

Thanks,

 

[westheimer1234]

so what is the rule of thumb when to model it as "solid rigid" as opposed to plate element flexible?

if you model it as "solid rigid" how were you designing the rebars?