I have taken raft as plate element and pile as embedded beam, the load applied is 100kN/m2. which output should i take to find the load shared by the raft and pile.
if we take axial force then the output is in terms of kN/m for plate how to take it in terms of kN/m2 or kN ?
Question 2 is when i applied uniform distributed load the soil has to settle uniformly right but i can see one side settlement is more other side settlement is less? what is the reason?
in the above figure there is no uniform displacement
Question 3 is as i said i applied uniform surface load but in the below figure even though i applied surface load i can see a single force direction what might be reason for this?
Hi,
1) Axial force in surface elements have the unit [force/length] because it's an axial force per meter width. Something with units kN/m2 is not an axial force but a stress, and units kN is an axial force in a 1-dimensional line element like a slender beam, not in a surface.
2) It's because the mesh is not symmetric. This leads to a non-symmetric stress and displacement distribution. Usually locally refining the mesh solves it.
3) In PLAXIS Input we don't draw all the arrows of a distributed load in order to not clutter the image too much. So usually one gets 2-3 arrows randomly placed, but sometims only 1 like in your case.
With kind regards,
Dennis Waterman
Answer Verified By: Niharika K
1.Is there any way to provide symmetric mesh?
2. raft size is 8mx8mx1m with 100kN/m2 surface load acting on the raft
the maximum axial load in raft is N1=104.9kN/m and N2=94.5kN/m
maximum axial load in each pile is 31.5 kN (i used 9 piles with 10m length, 0.4m diameter)
so how can i calculate the percentage of load shared by raft and pile
1) If you refine the mesh it will become more symmstric. It's not possible to enforce a 100% symmetric mesh as we use a random mesh generator.
2) I really don't understand why you're looking at axial forces in the raft when you're interesting in how much top load is carried by the piles and the raft. I recommend you lookup in the manual what axial forces are...If you apply a total load A on the raft, and you know that the sum of the pile forces is B ....what would you think is the load that is transferred from the raft directly to the soil? (Hint: A - B) With kind regards,
okay thank you so much
1. when i have given a pile data without any input for Tmax, Fmax i got so low axial load in pile which is around 31.5 kN in each for a uniform load of 100kN/m2 and settlements uz around 150mm under static loads
bottom & Fmax =10e3
uz has decreased to around 25mm and axial loads are around 1000kN
what is the reason for this?
2.
we can see maximum axial load value and also some other value in the figure
in this table we can see the variation of axial load along the pile data is given
how to find the exact axial load taken by pile when there is variation like can i go for avg of top and bottom value or can i go for avg of maximum and minimum axial load within the pile?
this was a question , since am applying 100kN/m2 on 8mx8mx1m pile raft i.e of 100x8x8=6400kN of load is applied
but if i take maximum axial load in each pile which is around 1000kN and find total axial load in piles will be 9 times the 1000kN =9000kN which is much more than applied load.
so how exactly should i take the axial load?
hope you get my question
1) Please thoroughly check the Reference and Material manuals on the meaning of Tskin and Fmax for embedded beams and you will understand why you get almost no force in the pile if you keep those values to zero.
2) I would suggest you find some literature on (design of) pile foundations to find out how they transfer load to the soil so that you understand why the axial force in the pile is not constant, but changes with depth.With the questions you ask I'm deeply worried about your understanding of pile foundations.