TEMPORARY STRUCTURAL MODELING DESIGN ON NATURAL BEACH PROTECTION SYSTEM ON INDONESIA WAVES CONDITIONS
Ocean waves can carry a large amount of energy so that it has the potential to damage the coastal area. Therefore, it is necessary to make a coastal protection to prevent such damage. One of the natural coastal protection is a mangrove forest. However, in the process of planting and growing mangr...
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| Format: | Final Project |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/43352 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Ocean waves can carry a large amount of energy so that it has the potential to
damage the coastal area. Therefore, it is necessary to make a coastal protection to
prevent such damage. One of the natural coastal protection is a mangrove forest.
However, in the process of planting and growing mangrove seedlings it is necessary
to have a protection to keep the mangrove growing properly so that it can function
optimally. Mangrove seedlings protection usually called temporary coastal
protection which are geobag structures, bamboo piles,and other kind of protection.
Geobag structure is an effective temporary coastal protection and can be physically
modeled.
This final project will discuss the test of physical models of coastal protection
systems in the form of geobag structure models and mangrove models. Research
scenarios in the form of variations in weight and slope of the geobag structure and
wave variations with random wave types. This study reviews the effect of variations
in weight and slope of the geobag structure on transmission in coastal protection
systems.
The standard used in testing physical models of geobag structures is the book
Physical Models and Laboratory Techniques in Coastal Engineering (Hughes,
1993.). The scale used is 1:10. There are 3 types of geobag weight variations
modeled, which are 0.5 kg, 1 kg and 2 kg. Geobag is stacked to form a structure
with dimensions of the width of the upper part of 24 cm, width of the bottom of the
structure of 144 cm for a slope of 1: 1.5, and the width of the bottom of the structure
of 184 cm for a slope of 1: 2. The height of the structure is right at the MSL of 40
cm. The mangrove model uses a laying configuration 10 cm apart.
Random wave variations are variations in significant wave height (Hs) and peak
periods (Tp). The steepness of the wave is adjusted to the wave conditions in
Indonesia of 0.0005-0.006. Significant wave heights used in this study were 15 cm,
10 cm and 8 cm. The peak period ranges from 1.2 seconds to 5.5 seconds. In this
study there are 8 structural scenarios with 9 wave variations.
The effect of geobag weight on the wave transmission on the coastal protection
system is quite significant, the average value of the transmission coefficient on the
slope of the structure 1: 2 for a weight of 0.5 kg, 1 kg, and 2 kg are 0.78, 0.69, dan
0.53, respectively. While the value of Kt on the slope of structure 1: 1.5 for a weight
of 0.5 kg, 1 kg, and 2 kg are 0.71, 0.65, dan 0.82, respectively. Geobag weight of 1
kg is more effective to reduce wave height than 0.5 kg and 2 kg in certain conditions.
The slope of the structure affect the coefficient transmision under certain conditions
where the slope of the structure 1: 2 is better in reducing the wave height in geobags
weighing 2 kg compared to the slope of 1: 1.5, but the slope of the structure 1: 1.5
is better at 0.5 kg and 1 kg weight than the slope of 1: 2 . The average Kt for geobag
weight 0.5 kg for 1: 1.5 structure slope and 1: 2 structure slope are 0.71 dan 0.78,
respectively, for 1 kg geobag weight are 0.65 dan 0.69, and for 2 kg geobag weight
are 0.82 dan 0.53. A structural slope of 1: 1.5 produces an average Kt better than
a slope of 1: 2 in 2 of 3 variations in the weight of the geobag.
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