FAQ

Q1: With reference to test A could you please specify the reference points for the output displacements (points A4a and A4b of the required results)?

  • A1: The displacements of the centre of each floor.

Q2: Could you please specify where the RC walls are placed on the building plan (side A or side D)?

  • A2 The walls are considered connected on Side D

Q3: With reference to the connection between the RC wall and the slab, is it a stiff brace with rotation released?

  • A3: The rotation is released, the only contribution of the wall is related to the horizontal movement of the slab (see Annex 2 "The linear model of the walls works in parallel to the flat slab part of the structure in resisting horizontal forces")

Q4: With reference to the Test B points 1) and 2) could you please clarify what do you mean with "damage state at the first punching"? Do you mean at the total loss of bearing load capacity of the first member achieving the punching or at the development of shear cracks due to punching?

  • A4: The request of "Lateral drift capacity of the structure, evaluated as the drift of the two floors at the first punching of a connection" means "provide the the drifts of the two floors in correspondence of the reaching of the maximum unbalanced moment in the first connection in the structure with a punching failure"

Q5: Lateral loads in test B1

  • A5: For test B the forces F2 imposed on the second floor slab where equal to twice the forces F1 on the first floor slab: F2 = 2 x F1

Q6: Gravity load distribution

  • A6: See attachment ‘Added Gravity Loads on Slab’ in the Blind Competition section

Q7: Test B1 and B2

  • A7: Experimental activity beyond test B1 is not included in the blind competition activities

Q8: Concrete testing results

  • A8: See attachment ‘Concrete Testing results’ in the Blind Competition section

Q9: Regarding the hybrid simulation, the damping matrix of the system is only due to the wall (Ceff on page 8 of “Models of the walls”, correct? And the mass matrix corresponds to the total system frame+walls (M on page 7)? So when we perform our dynamic analysis we have to have the same mass and damping matrices.

  • A9: The stiffness and damping matrix with which the walls were modelled in the pseudodynamic tests are are reported at page 8 of “Models of the walls”. The mass matrix of the total system (frame+walls) is reported at page 7. In modelling the pseudodynamic test as a transient dynamic analysis it is important to use the mass matrix in page 7 as the mass matrix of the total structure (since the inertia foreces during the pseudodynamic tests were computed with this matrix) and the stiffness and damping matrices in page 8 to represent the walls.

Q10: For the calculation of the base shear (prediction requested for test A), are you calculating it as mass*absolute acceleration at each floor, or from the reactions in the columns and walls?

  • A10: From the pseudodynmic test, we obtained the forces in the actuators (that is the shear in the column). You must find the shears in the columns without adding the damping forces.

Q11: Do we have to include the damping forces when reporting the base shear?

  • A11: The damping forces and the inertias create part of the forces balanced from the columns shear (the others are balanced from the walls).

Q12: You are always testing the same structure: first test seismic test (serviceability and design) and then cyclic test to failure of the previously damaged structure. So in our simulation we have to do the same, dynamic analysis followed by pseudo static.

  • A12: The structure is the same undergoing seismic service and ultimate tests, and cyclic testing. The ways to carry out the simulation are your choice.

Q13: 2. Test A point 2.2: Prediction requested, we have to report global shear force, does this include the walls or only columns?

  • A13: For test A, report the values for the columns only, without the walls.

Q14: Test B point 3.2: Predictions requested, should we report shear, axial force and moment at the maximum lateral load or first punching, or both? 

  • A14: For Test B, report the shear, axial force and moment at the maximum lateral load.