Hamid Bayesteh - High Performance Computing Lab, School of Civil Engineering, University of Tehran, Tehran, Iran
High Performance Computing Lab School of Civil Eng Jandaghi Alaee - Civil Engineering Department, Shahrood University of Technology, Shahrood, Iran

The liquefaction is response of loose saturated sand to cyclic loading of earthquake in which the sand loses its strength as a result of excess pore water pressure and tendsto liquefy. Accordingly, there is a high potential for lateral movement of soil on slop and severe damage to structures in coastal ports during earthquake as reported around theworld [1]. Generally, excessive pore water pressure in vulnerable soils during earthquake has twofold unwanted effects on structures as: • lateral and vertical strength reduction of soil• additional lateral load due to the lateral spreading/movement of soils on slope In this study, the flexural mode of failure in marine piled-structure, as one of the most important cases of maritime structures is investigate and local strengthening of vertical piles in a real case is examined. Upper and lower band of lateral strength of soil is considered to adoptstrengthening length of piles.