Answers to the most frequently asked questions (FAQ) will be posted here. Questions can be submitted to the organisers via the email: blind-prediction@uclouvain.be
In Table 1 of the “Test Description” pdf file, the steel reinforcement properties are given. What was the length of the steel reinforcing bars used for the tension tests that provided these values?
The length of the reinforcing bars were 500 mm. The gauge length used to measure the strain (i.e., the extensometer) was 100 mm.
What were the prestressed force applied to all the vertical and horizontal bars in the foundation of the wall and the two additional foundation blocks?
For unit UW1, the vertical threaded bars in the foundation of the wall were prestressed to 300 kN. The remainder of the vertical and horizontal bars in the foundation of the wall unit UW1 and foundation blocks were prestressed to 500 kN. For unit UW2, all horizontal and vertical bars in the foundation were prestressed to 500 kN. It is noted that all of these bars are Φ36 mm.
Are the threaded rods used horizontally in the head/collar of the wall, connected to the blue beam used for applying the horizontal loads, pre-stressed; and if so, what force has been used?
The Φ24mm threaded rods in the collar of the wall were prestressed using a small pneumatic nutrunner to a minimum force of approximately 75 kN. For unit UW1, the beam and applied load to the collar/head of the wall was snug and rigid. For UW2, a very small opening could be observed between the loading beam and the collar/head of the wall for the actuator under traction. This gap did not exceed ∼5mm and overall did not affect the loading protocol, since displacements are measured and imposed with respect to a fixed reference system.
For the loading protocol of UW1, are the displacements measured from the strokes of the actuators, or measurements on the wall surfaces?
The displacements of the wall were measured by two string pots (i.e., potentiometers) that were connected to the center of the steel plates on the boundary ends of the collar (head) of the wall. These string pots measure the displacement of the wall at a height of 2250 mm above the foundation, and at the centerline of the flange end surfaces, with respect to fixed external columns independent of the test setup. For UW1, the measured displacement was taken as the average of the two string pots to coincide with the warranted displacement via the loading protocol. This is illustrated in Figure 2b of the “Test Description” document.