Knapsack Placing of Blocks Assess on Wall Stability in Seismic Regions and Proper Section Recommendation

Concrete block quay walls consist of solid or hollow concrete blocks sitting on each other to form the wall section. In this type of walls geotechnical conditions, design calculations and the ability of contractor determine the blocks dimensions. In these walls, resistance against applied loads is provided by wall weight. To reduce active soil pressure and increasing the wall stability in seismic regions, a hunchback section is formed by placing a protruding knapsack to the landside. In the knapsack formation, wall stability will be increased. For knapsack section special considerations such as trimming the blocks, more accuracy in setting the blocks and consequently increases in construction costs should be considered. In this article, by conducting pseudo-static analysis in different earthquake levels and for various wall heights relative comparisons have been evaluated between knapsack and simple (vertical front face) sections. Finally suggestions about proper section of quay wall have been recommended.