SERA Project
Blind Prediction Competition
Frequent doubts
Rod ends
Diagonals details
The cut of the diagonals have been designed on site, according to Literature references (Cangi 2012, Giacometti 2000)
The mortar joints thickness at the extrados was fixed at the value of 1 cm, controlled by timber small pieces.
The webs of the vault were defined as "principal" and "secundary" for construction purposes. The bricks of the diagonal (principal web) present two cuts:
1° - in contact with the scaffolding;
2° - to make its surface planar to substain the brick of the secundary web.
The angles of the cuts decrease with the heigth of the vault, along its curvature.
The system of the rod ends was designed in order to avoid the torsional behaviour of the supports and to induce the longitudinal one, associated to in-shear deformation of the abutments.
The same type of connection was adopted both in longitudinal and trasverse direction.
The U shape connection hosts the rod ends which are linked through a vertical bolt.
This steel element (U shape) is connected directly to the UPN profiles in contact with the fixed masonry piers. Along the other edges of the mock-up, the U shapes are directy welded to the steel masses of the movable piers.
UPN corrigendum
The UPN 300 profiles which host the rod ends are placed at a distance of 15 cm from their external surfaces and about 5 cm from the external profile of the masonry fixed piers, centered with the cables.
Frequently asked questions
Q1 - Did you build the wallets on the facility or somewhere else and you move it?
A1 - We moved the wallets. The wallets were built closed to the vault, in order to keep the same environmental condition as the test specimen. Then, we moved the wallets to be tested
Q2 - Diagonal compression tests. In ASTM E519 the equation to define the shear strength is given according to the vertical pressure and the area of the sample S = 0.707Pv/A. How did you define the tensile strength then?
A2 - We defined the tensile strength according to the relation ft = 0.5Pv/An.
Reference: G. Guerrini et al., “Material Characterization for the Shaking-Table Test of the Scaled Prototype of a Stone Masonry Building Aggregate,” in Proceedings of XVII Convegno ANIDIS “L’Ingegneria Sismica in Italia,” 2017, no. January 2018.
Q3 - Does the positive direction correspond to North or South?
A3 - Positive direction from South to North and from West to East. You can see it from the pics of the gallery and from the instruction pdf file (page 7).
Q4 - Internal friction coefficient. We are wondering if this value is the friction coefficient (0.785 which is the tangent of 38 degrees) or if it is the friction angle in rad (0.785 equal to about 45 degrees).
A4 - It corresponds to the friction coefficient thus to 38 degrees of friction angle
Q5 - Triplets. Is the thickness of the joints equal to 10 mm? Do the total dimensions (173x223x118 mm) of the triplets consider also the exterior levelling layers of mortar?
A5 - The triplets are made up of three rows of solid ceramic bricks with the nominal dimensions: 230 mm length, 45 mm high and 110 mm thick. The joints thickness is in average 10 mm per each joint. A thin layer of levelling mortar was placed on the faces where the precompressive force will be applied (side faces). The total dimensions given in the spreadsheet file also consider the levelling mortar layers.
Q6 - Regarding the file "total_masses_material_disposition.pdf". Is the mass of each part estimated from the equivalent density and the corresponding volume?
A6 - The parts related to masonry were estimated based on the assumption of the equivalent densities and the design volume (autocad model).
While the steel masses and RC. slab mass are known. The purpose of the document is to show the distribution of the materials and to have a general idea of the weight of the model.