Let's say that the problem b) is changed to "the non-structural elements are not likely to be damaged by large deflection", will you still use the summation from (Delta2+Delta3) to compare with the limit L/240 as stipulated by ACI Table 24.2.2? Some engineers have raised up an issue, due to the possible visually offensive sagging of the structural member, the total deflection (Detal1+Delta2+Delta3) should be used to compare with L/240 as this is the limit for preventing from visualizing the obvious sagging. Why does ACI only only focus on the damage of the non-structural elements and neglect the aesthetic issue? What is your opinion about the aforementioned point of view?
Are you sure that delta4 should be considered in the long term calculus? I think the sum for the total should be delta1+delta2+delta3 instead. Great video anyways.
I reviewed the problem statement and it is fine to consider delta4 since there is a 10 year pause in the middle (it could be because the construction is abandoned due to lack of funds or problems at work for example). Good practical example! I understand that it does not apply to the most common cases where the work continues directly and there are no long pauses of years.
why we do not use the Creep Coefficient to calculate the long term deflection ? or how to use Creep Coefficient to calculate the long term deflection ?!
You use "n-1" for the compression steel so that you can use gross section properties for your concrete region. This is taking 1*As and moving to Ac which gives you Ag.
