NBN ISO 20987:2021

This document refers to connections in precast frame systems, either for single-storey or multi-
storey buildings. The connections for all orders of joints are considered. Large wall panel and three-
dimensional cell systems are not considered.
According to the position in the overall construction and of the consequent different structural
functions, the seven following orders of joints are considered:
a) mutual joints between floor or roof elements (floor-to-floor) that, in the seismic behaviour of the
structural system, concern the diaphragm action of the floor;
b) joints between floor or roof elements and supporting beams (floor-to-beam) that give the peripheral
constraints to the floor diaphragm in its seismic behaviour;
c) joints between beam and column (beam-to-column) that ensure in any direction the required degree
of restraint in the frame system;
d) joints between column segments (column-to-column) used for multi-storey buildings usually for
dual wall braced systems;
e) joints between column and foundation (column-to-foundation), able to ensure in any plane a fixed
full support of the column;
f) fastenings of cladding panels to the structure (panel-to-structure) that ensure the stability of the
panels under the high forces or the large drifts expected under seismic action;
g) joints between adjacent cladding panels (panel-to-panel) possibly used to increase the stiffness of
the peripheral wall system and provide an additional source of energy dissipation.
Simple bearings working by gravity load friction are not considered. Sliding and elastic deformable
supporting devices neither, being all these types of connections not suitable for the transmission of
seismic actions.
The document provides formulae for the strength design of a large number of joint typologies.