Engineering Know-How: Lessons from Earthquakes and Rules for Seismic Design - Dynamic Behavior of Concrete and Seismic Engineering - page 344

segment between two plastic hinges breaking under the influence of shear load, it
has to be designed for the maximum shear load that is obtained by expressing the
equilibrium using the following formula (Figure 9.18):

MM

DRd CRd

V J [9.3]

Sd CD , Rd

l

cl

V Sd,CD

M DRd

M CRd

Figure 5

Figure 9.18. Transverse load determined by capacity design

In this expression, M DRd and M CRd refer to the design resistant moment at both
ends, l cd is the segment length and J Rd is the over-capacity coefficient.

The V Sd,CD shear load thus obtained is used to design the beam segment and does
not have any direct connection to the shear load obtained by structure calculations
for the same element.

9.4. General design

9.4.1. Design principles

Eurocode 8 encourages designers to adopt layouts that ensure the good behavior
of the structure. These include using bracing that is continuous down to soil level,
and considering the symmetry, hyper-staticity, strength and stiffness in both
horizontal directions, strength and stiffness with regard to the vertical axis torsion,
the existence of horizontal diaphragms on different levels to distribute the seismic
loads on the bracing elements.

Regular behavior should be the goal. It is best achieved by implementing simple
and compact shapes, horizontally and vertically, and to achieve this, the structure
can be designed as a collection of dynamically-independent blocks, each of which
have regular properties. Regular structures simplify the process of performing both
action and behavior coefficient calculations.