Rigid Bodrum Earthquake Load Calculation with Modal Analysis Method

[civilmehmetkara]

In the modal analysis, the earthquake load coming to the basement in the x direction is 14,269 tons, but according to the equivalent earthquake method (Fbk = Ao I wbk / 1.5) it should be 54,858 tons. Since VtB<0.9xVt in X and Y directions, the internal forces were increased by 0.9xVt / VtB as per Equation 2.16 of Earthquake Load found by modal analysis on all floors (except the rigid basement). However, this enlargement process was not carried out in the basement where the rigid basement curtain is located, the Earthquake Load found by direct modal analysis was taken into account in the calculation. The program automatically accepts 14,269 tons of earthquake load that it finds in the dynamic analysis result. The same is true for the Y direction. There must be something I missed in the regulation. What is your opinion on this issue? (0.9xVt / VtB =1, 1541 )

 

[HakanŞahin]

In the modal analysis, the earthquake load on the basement floor in the x direction is 14,269 tons, but according to the equivalent earthquake method ( Fbk = Ao I wbk / 1.5) it should be 54.858 tons. VtB<0.9xVt in the X and Y directions Earthquake Load found by modal analysis on all floors (except rigid basement) was increased by 0.9xVt / VtB as per Equation 2.16. However, this enlargement process was not carried out in the basement where the rigid basement curtain is located, the Earthquake Load found by direct modal analysis was taken into account in the calculation. It automatically accepts the 14,269 tons found in the dynamic analysis result as earthquake load. The same is true for the Y direction. There must be something I missed in the regulation. What is your opinion on this subject? (0.9xVt / VtB =1, 1541 )

Hello, in the Regulation It says "internal force and displacement magnitudes" will be enlarged. The magnification process is applied to the element end forces obtained from earthquake forces. You can see the results/design results by clicking on The incremented value is shown in bold. In the design results, there are also 2.75 30% increase and buckling coefficient increases, if any. The subject you mention is left to the initiative of the engineer. If you want the beta boosting process to be applied in the basement floors, you must select the relevant option in the analysis settings. You can also see that 2.8.5 is applied in the column report.