This blog article is related to the recent post of Creep Analysis 1. Feel free to access the previous article via this link: Creep Analysis 1. The same problem can be solved more elegantly, as shown in the same paper by Dr. El-Badry.
The stiffness equation between time t1 and t2 is
Here, the displacement changes which would occur between time t1 and t2 without any support changes are
The stiffness equation at time t0 is
Substitute Eq(5) into Eq(2)
Substitute Eq(6) into Eq(1)
Substitute Eq(8) into Eq(7)
We know the fixed end force changes between time t1 and t2, and we can calculate the reaction changes between the same time intervals. Not all commercial programs can handle these fixed end forces, but we can convert fixed end forces into nodal loads and do the post-processing easily.
This method is more elegant and faster than the previous method and very helpful to understand the concept of creep analysis. However, the computational quantity is no longer a problem with modern 32-bit computers. The author believes the previous method is also a good one to implement with computers once the reader fully understands this method.