Recent content by BeFEA

Thank you for your answers. I don't know why, but think I had never heard of the Buckingham's Pi Theorem. I didn't go through it in detail but it seems complicated. I keep believing that there is a simpler solution. For instance, if someone has experience with the application of Similitude laws...

Hello! I have a question that I would like to share with you. Although there is little chance to encounter this problem in practice, I think it is good for a structural engineer to pause and ponder about it for a few seconds. For me, it is actually a real-life problem. Here it goes: - Let's...

Hi xeneize10! Your question seems too generic to me. You have to perform a structural analysis to determine the maximum displacements of the structure. Depending on the complexity of your structure, you might not be able to complete your task with hand calculations.

I think we reached a conclusion. I think the proof provided by KootK is correct and very nice. I tried to generalize it, and I reached to the conclusion that the drift ratios are related only by the ratio of the building heights, no matter what the mass of each building is! Again, this is valid...

Theoretically, a truss should not have continuous chords. Practically, the moment in the chords is zero when the structure is shaped like a stable "truss". The equilibrium of joints shows that there are no bending moments in such elements. Yours would not be a stable "truss" if you had full...

Do you have noticeable vibrations on your slab? If you don't, maybe you can use fiber reinforced polymers to increase the hogging and sagging moment capacities. It is not very expensive for the quantities you will need. Check with your local providers.

KootK, I am not 100% convinced for your analytical proof yet. Does your proof work if building 1 has distributed mass m1 and buildimg 2 has mass m2 (where m1 is different from m2)? Also, for the 6 storey building I think the highest drifts would be around mid-height.

Sorry, I answered before reading your reply.

The two buildings can have the same mass (OK, theoretically) but compensate with stiffness such that both buildings have the same fundamental period... Am I missing something here?

But wait, why is #5 true? Since both buildings have the same period, the spectral acceleration should be equal for both. You are assuming that the mass of building 2 is twice the mass of buildng 1, right? This doesn't have to be true, am I right?

Can someone think of a sound reason why the conclusion reached so far (larger drifts in the three storey building) can't hold for the general case?

Thank you for your precious time. I ran time history analyses (linear and nonlinear) and they all showed that the drifts in the building with 6 stories are smaller. Now I invite you all to find a single example/scenario in which the drift ratios would be larger for the taller building, and...

I think you should specify the country or code you are referring to. I had never heard that two concrete cylinders were sufficient. I guess it all depends on the country and specific rules for your country.

I need to make another clarification. When I say drift, I mean interstorey drift ratio.

In order to be able to solve the problem, let's focus on buildings with uniformly distributed mass along the height. Even simpler, let's focus on buildings with the same mass in each storey. Are the drifts in the taller building always smaller?