Hello everyone,
I have a question regarding the total of P-Delta analysis for building with two tower
The building is as follow:
The 1st Floor to 5th Floor is connected as podium
6th Floor to 25th Floor is separated as each tower
26th to 28th Floor is connected again
and another 2 floor separated for each tower
This building is located in low seismic area but the seismic load is still the governing lateral load rather than the wind load. The lateral load Cs = 1%
Resulting in P-Delta governing the structure building design
Based on ASCE 7-22
For seismic mass, the load is 1.0 Dead + 0.25 Live
For P-Delta Analysis, the load case is 1.0 Dead + 1.0 Live (Assembly Live Load) + 0.5 Live (Residential Live Load)
Checking on the P-Delta analysis, that the maximum stability coefficient (θmax), with Cd = 4.5 (Intermediate Moment Frame & Ordinary Shear Wall), with conservative β = 1
θ max = 0.5 / βCd
θ max = 0.111
the stability coefient equation
θ = (P ∕ hsx) / (Vx ∕ Δxe)
If I am using the P (Vertical design Load) of the total building weight for checking, the result of instability P-Delta ( > θmax), at detached level of tower 1 and tower 2 especially at 6th-12th floor
But If the load is calculated as each tower (for example P1 for tower 1 and P2 for tower 2), resulting in θ < θmax
I appreciate your comments for this
I have a question regarding the total of P-Delta analysis for building with two tower
The building is as follow:
The 1st Floor to 5th Floor is connected as podium
6th Floor to 25th Floor is separated as each tower
26th to 28th Floor is connected again
and another 2 floor separated for each tower
This building is located in low seismic area but the seismic load is still the governing lateral load rather than the wind load. The lateral load Cs = 1%
Resulting in P-Delta governing the structure building design
Based on ASCE 7-22
For seismic mass, the load is 1.0 Dead + 0.25 Live
For P-Delta Analysis, the load case is 1.0 Dead + 1.0 Live (Assembly Live Load) + 0.5 Live (Residential Live Load)
Checking on the P-Delta analysis, that the maximum stability coefficient (θmax), with Cd = 4.5 (Intermediate Moment Frame & Ordinary Shear Wall), with conservative β = 1
θ max = 0.5 / βCd
θ max = 0.111
the stability coefient equation
θ = (P ∕ hsx) / (Vx ∕ Δxe)
If I am using the P (Vertical design Load) of the total building weight for checking, the result of instability P-Delta ( > θmax), at detached level of tower 1 and tower 2 especially at 6th-12th floor
But If the load is calculated as each tower (for example P1 for tower 1 and P2 for tower 2), resulting in θ < θmax
I appreciate your comments for this
