04-06-2010, 11:20 AM
Aslam writes:-
I think Graph of distance VS settlement is of only one software and not for all software.
Regarding values of settlement,
settlement/bearing pressure under raft depends also on type of soil (clayey, sandy c-@ soil etc) in addition to magnitude of load. And settlement/pressure distribution may be concave or convex depending upon type of soil which may be modelled in FEM software using soil subgrade for raft and soil spring for raft.
Comment:-
Please note that there were 2 issues raised in my post (one deals with the load distribution and the second with settlement). The first part does not refer to settlement but to load distribution on piles/raft and the soil spring (for raft).
As to the graphs, I have same hunch as you. It is supposed to be a contour graph traced by only a soft ware; but from the footnote (encircled), it seems obvious that the writer was comparing some soft wares (refer to the footnote). Excerpts are:-
· The difference between the pile load distributions could be attribute to a number of reasons including:-the FE REPUTE and PIGLET models take account of the pile-soil-pile interaction whereas SOM modeled the soil as springs connected to the raft and piles using an S-Frame analysis.
· The HCL FE analysis modeled the soil/rock using non-linear responses compared to the linear spring stiffnesses assumed in the SOM analysis.
· ………
This clearly shows that comparisms were being made as to the outputs of some soft wares (not only a soft ware since it will make no sense for one to compare the output of a soft ware with itself). It is for this that I was doubting the relevance of the statements if the graph displayed is that of the output of but only one soft ware (for which you are in agreement with me).
Again, settlement is proportional to load and the soil characteristics. Since we are talking of a relatively limited area (a very small one indeed), the issue in variation in soil characteristic does not play any part since it is most probable that the soil within the space occupied by the foundation has an assumed uniform characteristics (the graph confirmed this since the soil could not have such a well defined, sharp and regular variation as traced in the settlement graph). Based on this, I do not see the reason why the piles subjected to lesser load should suffer greater settlements.
What do you think about it?
Regards
Teddy
I think Graph of distance VS settlement is of only one software and not for all software.
Regarding values of settlement,
settlement/bearing pressure under raft depends also on type of soil (clayey, sandy c-@ soil etc) in addition to magnitude of load. And settlement/pressure distribution may be concave or convex depending upon type of soil which may be modelled in FEM software using soil subgrade for raft and soil spring for raft.
Comment:-
Please note that there were 2 issues raised in my post (one deals with the load distribution and the second with settlement). The first part does not refer to settlement but to load distribution on piles/raft and the soil spring (for raft).
As to the graphs, I have same hunch as you. It is supposed to be a contour graph traced by only a soft ware; but from the footnote (encircled), it seems obvious that the writer was comparing some soft wares (refer to the footnote). Excerpts are:-
· The difference between the pile load distributions could be attribute to a number of reasons including:-the FE REPUTE and PIGLET models take account of the pile-soil-pile interaction whereas SOM modeled the soil as springs connected to the raft and piles using an S-Frame analysis.
· The HCL FE analysis modeled the soil/rock using non-linear responses compared to the linear spring stiffnesses assumed in the SOM analysis.
· ………
This clearly shows that comparisms were being made as to the outputs of some soft wares (not only a soft ware since it will make no sense for one to compare the output of a soft ware with itself). It is for this that I was doubting the relevance of the statements if the graph displayed is that of the output of but only one soft ware (for which you are in agreement with me).
Again, settlement is proportional to load and the soil characteristics. Since we are talking of a relatively limited area (a very small one indeed), the issue in variation in soil characteristic does not play any part since it is most probable that the soil within the space occupied by the foundation has an assumed uniform characteristics (the graph confirmed this since the soil could not have such a well defined, sharp and regular variation as traced in the settlement graph). Based on this, I do not see the reason why the piles subjected to lesser load should suffer greater settlements.
What do you think about it?
Regards
Teddy