STABILITY ANALYSIS OF CONCRETE SEAWALLS AGAINST EARTHQUAKE FORCES

Seawalls are commonly constructed to prevent landward erosion of shorelines and maintain configuration of the area behind them against wave action. Recently, rising of sea levelparticularly in the northern coastline of country, has caused special attention to design and construction of seawalls in that region. One of the important factors in design of seawalls and stability control of such structures is their safety factor (S.F.) against overturning. Present studyconsiders all effective parameters on stability of seawalls; appropriate equations are presented for calculation of the safety factor against overturning. The equations are presented in such a way that designers can easily use them. Furthermore, different design curves are also obtained bysensitivity analysis of seawall stability. Using the presented equations can be a great help for optimum design of seawalls against different loads combination, particularly for earthquake forces. The results of present study clearly indicate that the optimum dimensions for a typical rectangular or trapezoidal concrete seawall, as far as the stability of such structure is concerned, highly depends on the slenderness of the wall (ratio of the wall height to wall width). Increasing this value from a critical range of 1.5 to 2 results in drastic drop of the safety factor against overturning. Also the presence of earthquake forces enhances this reduction leading to a narrowbound confidence interval for the safety of concrete seawalls.

Keywords:

Seawall , Wave , Stability , Safety factor , Optimum Design , Earthquake Force , Overturning