Repair and reconstruction of engineering structures - Assessment and Refurbishment of Steel Structures - page 276

solution; such a method has already been discussed in several publications, e.g. [83],
[84], [85], but the results of expansion operations have only been judged subjectively—
no measurements were carried out before and after, such as by filling the tanks with
water.
The case described below is a notable example due to the fact that despite the shortage
of time (the tank was to be put into operation as quickly as possible), the survey of the
shell shape was carried out for three stages:
• After an emergency deformation
• After filling the tank with water
• After the tank had been emptied.
Comparison of the three surveys gives an idea of the effectiveness of the hydraulic
expansion technique when used in an emergency repair to a shell damaged by negative
pressure generated in the tank.
Figure 6.115 Shell deformation of a
tank of volume 196 m 3