Mohammad Hadi Moeini - PhD in Coastal Eng., Pouya Tarh Pars Cons. Eng. Company, Tehran, Iran
Mahmood Pourali - PhD St. in Hydraulic Structures Eng., K. N. Toosi Uni. of Tech., Tehran, Iran
Majid Jandaghi Alaee - PhD in Coastal Eng., Pouya Tarh Pars Cons. Eng. Company
d Mohammad Rahim Ravan-Bakhsh - Omran-Sahel Insitute, Tehran, Iran

Although rock is the most popular material for construction of the coastal structures, such as breakwaters and various types of shore protections, there are difficultiesin providing appropriate rock materials in some areas based on the economic and environmental conditions. In these cases, substitute materials such as concrete blocksand sandbags could be the alternatives of rock materials. In the plentitude of sand, for example when a project includes dredging, the sandbag is one of the best options fromeconomic and environmental viewpoints. Due to development of various types of the geotextiles, these materials have become one of the best selections tobe used in making sandbags. In such cases, determination of the type of geotextile, technical specification of it and dimensions of the sandbags are very important. Specification of the final product mostly depends on the bag size and texture quality. In this study some experimental tests have been designed and conducted to examine effective parameters. On this basis some recommendations have been proposed for the geotextile properties and size of sandbags for using in breakwater and shore protection structures.