Seismic risk management for water pipeline networks - Seismic Risk Analysis and Management of Civil Infrastructure Systems - page 622

Nut

Bolt

Spigot

Lead Yarn

Fixing ring

Insert sleeve

Rubber ring

(a) Old type-CIP (b) Old type-DCIP

Rubber ring Centering rubber

Spigot

Locking ring

Y

Y : Effective gap

Insert sleeve Stopper

(c) New type-DCIP

23.3 Old and new types of CIP and DCIP joints.

Table 23.2 Seismic performance of old-type and new-type joints

Resistance of joint (mm)

Type Major Moderate Major

Mean
Old joint 5 10 15

New joint 30 45 60

Coeffi cient of variation
Old joint 0.2 0.25 0.3

New joint 0.05 0.05 0.1

Source: Wada et al. (2010).

even in the case of large displacement induced by an earthquake. The
seismic performances of these joints are compared in Table 23.2 in terms
of acceptable displacement in the axial direction.
Figure 23.4 shows a restraining mechanism of the new-type DCIP joint.
If the ground displacement is larger than Δ joint that can be accommodated

by a single joint, the other two joints neighboring the fi rst one can move
together to absorb the remaining ground displacement over the interval of
l eff as shown in Fig. 23.4b.