Someone have modeled a pile for lateral loading in PLAXIS 2D software
he asked: In the output file, one table we can check for the results.
Could anyone please tell me what is meant by Nmin,Qmin,Mmax ?
Answer: Old version of Plaxis 2D definitely CANNOT be used to model the laterally loaded pile. In the newest version there is a pile element. But even with this element provided, it is not for calculation of laterally loaded pile. It is a 3D problem, analysis sholud be done in Plaxis 3D.
Q, N, M refers to shear, normal (axial) and moment.
A graduate student from Texas A&M University asked:
I’m currently working on a project related to Rail Embankments. How a repetitive/ cycling loading can be simulated in a typical FEM model (I’m using PLAXIS 2D) considering the effect of fatigue.
Use HS small soil model, cyclic loading can then be simulated by choosing dynamic analysis and the loading vs time can be created by making a text file first in Notepad (left column is time, right column is magnitude of loading).
The problems faced by engineers in dealing with soils lie not only on the fact soils are particulate material which have much more complex behavior compared to concrete and steel, but it is also lie to the attitude of those engineers who have no enough “respect” toward the soils they faced.
Soils need to be understood and to be well treated, just like we try hard to understand and to treat a lady. There are four aspects of geotechnic that we need to learn and to understand, those are:
– The soil profiles (type and distribution)
– The ground water table, i.e. , its position, indication of ground water flow, existence of perched water table and artesian water pressure.
– Characteristics and behavior of the existing subsoils
– The right soil model to be taken for designing the planned geotechnical structure.
For all the above, time and money need to be invested. Ask the rich and successful peoples, whether they “invested” time and money to chase for the ladies that eventually became their wives?
Like those ladies, in order to understand the soil behavior, time and money also need to be given (invested) to the soils,
If the engineers understand the above four aspects well, then “comfort” will be belong to the engineers, and ultimately will also belong to the owner and the end users of the said structures / buildings.
On the other hand, if we treat the soils badly, and only give the soils unreasonable amount of time and money, just like cruel parents treat their step children badly. Then: “just wait for the retaliation” of the step children.
You don’t believe me? Look back to the failure of Sano Tower at Pluit area, North Jakarta, in 1991; or to the current “failure” of “S tower” near Cawang, South Jakarta; or to the badly settled “GB tower” at Pluit, North Jakarta. Look back to the Nicoll highway deep excavation (for MRT station) failure in Singapore in 2004; and many other geotechnical failures.
One of the causes of the those failures is the attitude of IGNORANCE or DO NOT CARE or “ASSUMED” TO KNOW BETTER than any other engineers. The over insistence of saving money, all the owner know is only SAVE, SAVE and SAVE. They do not want to spend time and money for soil investigation, and the engineers involved failed to convince the owner to spend the money!! The owner even want to save more, by using bidding process, to suppress the consultant!!! They forgot the words: “You buy peanuts, you get monkeys!”. They feel they are so clever and so able to get cheap price!!! They only want to higher engineers with low fees!!! They forgot CHEAP is not the same as ECONOMICAL. Indirectly, they treat the soils, where their structures shall be built, as step children!!
Then, one day, the step children will retaliate, and when they do so, the retaliation can be so destructive and fatal!!
So, go and tell the owner of the money:
TREAT THE SOIL AS A LADY, THEN THE COMFORT IS YOURS.
TREAT THE SOIL AS A STEPCHILDREN, THE REVENGE IS WAITING FOR YOU!!
Written by Gouw Tjie Liong(English version: April 12, 2015)