Eurocode 8-1 Design of
New Buildings
Eurocode 8-3
Strengthening and
repair of buildings
Eurocode 8-1 Design of New Buildings
The seismic design of the building determines how the
(roughly) given peak global displacement and peak kinetic
energy are distributed to the various elements of the building.
To distribute them just to those elements best suited to
withstand these demands, current seismic design codes use
“capacity design” as the main instrument. In the detailed
design phase “capacity design” works with and on the strengths
of individual elements to ensure that all-along the load path of
inertia forces, from the masses to the foundation, the strength
of the structural system is governed by the ductile elements.
Although capacity design is used during detailed design, its
effectiveness depends strongly on the layout and sizing chosen
early on, during conceptual design.
Eurocode 8-1 Design of New Buildings
- Strong column and weak beam design;
- Shear failure after ductile “failures” Capacity design;
- Three levels of ductility:
- Low ductility level (q=1.5 for R.C. buildings);
- Medium ductility level;
- High ductility level;
Eurocode 8-1 Design of New Buildings
Eurocode 8-1 Design of New Buildings
Eurocode 8-1 Design of New Buildings
- Design for low dissipation capacity
recommended for low seismicity cases;
applying only the rules of Eurocode 2;
- Design for medium and high dissipation capacity
provide an overall ductile behavior;
ductile modes of failure (e.g. flexure) should precede brittle failure
modes (e.g. shear) with sufficient reliability;
Eurocode 8-1 Design of New Buildings
- Design for medium and high dissipation capacity
Structures designed, dimensioned and detailed according to
earthquake provisions, enabling the structure to develop stable
mechanisms associated to large dissipation of hysteretic energy under
repeated reversed loading, without suffering brittle failures.
Eurocode 8-1 Design of New Buildings
- Capacity design
Prevent brittle or undesirable failure mechanisms:
- Concentration of plastic hinghes in columns of single storey;
- Shear failure of structural elements;
- Failure of beam-columns joints;
- Yielding of foundations or of any element intended to remain
elastic;
Eurocode 8-1 Design of New Buildings
- Subsection 5.2.3.4 of Eurocode 8-1 defines rules for local ductility condition;
- Section 5.4 defines rules for DCM design:
- Minimum compressive strength level of concrete;
- Minimum dimensions for beams, columns and walls;
- Rules for indirect supports;
- Rules for design action effects.
Eurocode 8-1 Design of New Buildings
- Rules for design action effects for DCM:
- Bending moments and axial forces obtained from the analysis for
seismic design situation;
- Redistribution of forces according to Eurocode 2 is permitted;
- The design values of shear forces of primary seismic beams, columns,
ductile walls and lightly reinforced walls are determined according
specific rules of Eurocode 8-1 (5.4.2.2, 5.4.2.3, 5.4.2.4, 5.4.2.5);
Eurocode 8-1 Design of New Buildings
- Beams:
- In primary seismic beams the design shear forces shall be determined
according to capacity design rule:
- Shear forces are not obtained from the analysis but as a function of
the resistant bending moments:
Eurocode 8-1 Design of New Buildings
- Beams:
Eurocode 8-1 Design of New Buildings
- Beams:
Eurocode 8-1 Design of New Buildings
- Columns:
- In primary seismic columns the design shear forces shall be determined
according to capacity design rule:
- Shear forces are not obtained from the analysis but as a function of
the resistant bending moments:
Eurocode 8-1 Design of New Buildings
Eurocode 8-1 Design of New Buildings
Eurocode 8-1 Design of New Buildings
- Shear walls
Eurocode 8-1 Design of New Buildings
- Shear walls
