Page 211 - Handbook of Materials Failure Analysis

5 Case Study 207

FIGURE 8.7
The general view of Sikh Oumedour tank.

The tank is located in Sikh Oumedour village, on the valley of Sebaou, bounded on
theNorthbythemainstemoftheSebaouriverandonthewestbyatributarynamedAissi
river (Figure 8.7). Reading the geological report shows that the valley is composed of
quaternary alluvial deposits sitting on bedrock of tertiary Eocene marnes. This alluvial
layer about 50 m thick, characteristic of the middle Sebaou, consists of deposits of sand
and very dense gravel. This soil is identified as soil category type S2 (firm soil), accord-
ing to the Algerian seismic code. This parameter is classified as class B.

5.5 REGULARITY IN PLAN
The seismic movements result in overall torsion of structures when their center of
mass does not coincide with the center of rigidity. Torsion is an important factor
in vulnerability; its limitation should be systematically required. For this reason,