Engineering Know-How: Lessons from Earthquakes and Rules for Seismic Design - Dynamic Behavior of Concrete and Seismic Engineering - page 332

Figure 9.7. Rupture of a silo column with formation of a plastic hinge
Figure 9.8. Rupture of a column showing the influence of the shear load
As shown in Figure 9.8, bending failure is influenced by shear loads. As it takes
place, the column suffers the influence of insufficient transverse and longitudinal
reinforcements, and failure combines both effects.
In the case depicted in Figure 9.9, longitudinal reinforcements have allowed the
embedding section to withstand the moment quite well, but failure due to the shear
load started before a plastic hinge could form, because of insufficient transverse
reinforcements. This case highlights the importance of the sequence in which
plastification and failures occur - if the shear load-generated brittle failure had been
delayed beyond the onset of bending plastification of the embedding section, a
plastic hinge could have formed, which would have increased the chances the
column could have withstood the earthquake (see section 9.3.4).