Load-bearing walls structures
By suitably modulating the quantity of reinforcement, where the shape of the building allows it, it is also possible to obtain buildings which, from the point of view of their resistance to vertical and horizontal loads, shape up to be “lightly reinforced extended wall structures or “concrete structures with small amount of reinforcement” or “Large Lightly Reinforced Concrete Walls” (LLRCW) in accordance with the Eurocodes. The sections of the Eurocodes relevant to the subject are listed below:
Eurocodes: EC2 – “Design of Concrete Structures, Part I: General Rules and Rules for Buildings” – Chapter 12: with reference to partition systems in place called “Large Lightly Reinforced Concrete Walls” (LLRCW); EC8 – “Design of Structures for Earthquake Resistance, Part I: General Rules, Seismic Actions and Rules for Buildings” – Chapter 5: with reference to the partition systems in place defined “Large Lightly Reinforced Concrete Walls” (LLRCW).
DESCRIPTION OF THE DESIGN CRITERIA
In structures with “load-bearing walls” or “lightly reinforced load-bearing walls”, the box-like behavior of the structure must always be guaranteed so that in the presence of horizontal seismic actions, the walls come to work on their plane. To achieve this condition, it is advisable that: – The floors are capable of creating a rigid surface that allows the horizontal actions to be distributed among all the bracing elements (the perforated walls due to the inevitable presence of doors and windows). The horizontal actions are distributed among the various bracing elements proportionally to the stiffnesses and shear bending of the walls; in order to carry out this task, the floors must be considered as wall beams in their own plane and it is essential to verify that the reinforcement of the chains is sufficient for this purpose or if, on the other hand, it is necessary to increase it. – The load-bearing walls develop along the two orthogonal directions. – The orthogonal walls are properly connected.
It is therefore of fundamental importance to carefully distribute the structural elements, so as to ensure effective overall behavior as regards both vertical and horizontal actions: a correct arrangement of the walls and openings ensures the stability of the building more than any other structural artifice.