Gabion as a coastal protection structure: a case study in Panjang Island Indonesia

Abstract

Panjang Island is a small island in Jepara, Indonesia which is very vulnerable to coastal damage due to crashing waves. Therefore, presence of coastal protection structure is essentially important. Gabion structure was constructed to protect this coastal area. Considering the age, the existing gabion structure needed assessment and analysis to ensure its performance in term of protecting the coastal area. This study aimed at assessing and analyzing the performance of the existing gabion structure. Data of the study were collected through observing the condition of the structure. Assessment was carried out by scaling 1 (minor) to 5 (severe damage). Results of the analysis showed that the value of stability to overturning was 3.96, while the stability to shearing was 2.07, the structure stability was in safe category. Soil pressure under the structure in σ max. was 0.39 kg/cm2, while σ min was 0.16 kg/cm2, which means safe. The condition of gabion as a coastal protection structure in section 1 was partially damaged with a moderate level of damage, in section 2, the damage was revealed to be a minor level of damage, while in section 3, the damage was in a minor level of damage.