Floating BreakwaterPreparation of Design and Implementation in Indonesia

Presented by

Andojo Wurjanto

SEMINAR FLOATING OFFSHORE STRUCTURES TECHNOLOGYITB Bandung, 26 June 2009

Breakwater*) = a man-made structure protecting a shore area, anchorage, or basin from waves. A harbor work.

*) Coastal Enginering Manual 2002-2008

Terminology

http://chl.erdc.usace.army.mil/

Harbor What is to be protected?

http://www-svsarah.com/

HighwayWhat is to be protected?

Private archiveJalan Raya Pesisir Kalimantan Barat Jul 2004

Tourist DestinationWhat is to be protected?

Private archivePantai Kuta Bali Feb 2009

CommunityWhat is to be protected?

Private archivePantai Kota Padang 2007

Economic AssetsWhat is to be protected?

Private archiveSawah, Pipa Minyak Pertamina di Indramayu Jan 2009

Conventional BreakwaterBreakwater the Protector

Made of rock or concrete. Built on seabed. Strength (stability) from its heavy weight.

Inonventional Breakwater: FloatingBreakwater the Protector

Must have buoyancy. Not founded on seabed. Wave attenuation due to its large size or energy transfer

to seabed by means of tether.

BoxTypes of Floating Breakwater

http://www.fdn-engineering.nl/

Box Floating Breakwater for Port of Hercule, Monaco, shown here being constructed in Spain

Type 1

Pontoon:Example ofApplication

Types of Floating Breakwater

http://www.supflex.com/

Pontoon Floating Breakwater: Example of application

Type 2

Pontoon: ConceptTypes of Floating Breakwater

Nece, R.E. dan Richey, E.P., 1972. Wave Transmission Tests of Floatring Breakwater for Oak Harbor. Water Resources Series, Technical Report No. 32. Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA

Type 2

Mat:Example ofApplication

Types of Floating Breakwater

Simm, Jonathan; Wallis, Michael J; danCollins, Ken; ed, 2005. Sustainable Re-use of Tyres in Port, Coastal and River Engineering: Guidance for planning, implementation and maintenance. Report SR-669, HR Wallingford, Wallingford, United Kingdom

Type 3

TFB = Tethered Float Breakwater: ConceptTypes of Floating Breakwater

Mulvihill, E.L; Fransisco, C.A.; Glad, J.B., Kaster. K.B., dan Wilson, R.E., 1980. Biological Impact of Minor Shoreline Structures on the Coastal Environment: State of the Art Review. Volume I. Report No. FWS/OBS-77/51, Biological Services Program US Fish and Wildlife Services, USA.

Type 4

Manufactured BreakwaterTypes of Floating Breakwater

Whisprwave Floating Breakwater http://www.whisprwave.com/

Type 5

Manufactured BreakwaterTypes of Floating Breakwater

Wavebrake Floating Breakwater http://www.wavebrakefl.com/

Type 5

AdvantagesFloating Breakwater

a) Biaya awal PGT untuk perairan dalam (lebih dari 4 meter).

b) PGT efektif meredam gelombang moderat (tinggigelombang tidak lebih dari 2 meter).

c) PGT cocok untuk perairan yang memiliki kondisi tanahlembek.

d) Terhadap lingkungan PGT berdampak kecil dibanding PG konvensional.

e) PGT dapat mudah dipindahkan.f) PGT tidak menyebabkan scour.

DisdvantagesFloating Breakwater

a) Perairan tidak terlindung sepenuhnya.b) Umur PGT pendek.c) PGT memerlukan biaya perawatan besar.d) PGT tidak efektif meredam gelombang besar (tinggi lebih

dari 2 meter).e) PGT dapat rusak sewaktu-waktu tanpa indikasi dini.f) PGT tidak efektif meredam gelombang agak panjang

(perioda lebih dari 6 detik).g) Jika struktur PGT terlepas dari jangkarnya, komponen

terapung dapat menjadi sumber bahaya (hazard).h) Belum ada pedoman perencanaan yang mapan.

Kondisi UmumFloating Breakwater in Indonesia

Kebanyakan dibangun oleh pemerintah sebagaiprasarana umum.

Prasarana yang membutuhkan banyak perawatan tidaksesuai sebagai prasarana umum.

PGT (Pemecah Gelomban Terapung) tidak sesuai untukprasarana umum di Indonesia.

Dimana PGT Sesuai?Floating Breakwater in Indonesia

Organisasi yang kesehariannya beroperasi secarasistematis dapat memanfaatkan kelebihan PGT.o Biaya awal yang murah.

o Masa layanan pendek tidak membutuhkan bangunanpermanen.

o Dapat dipindahkan dengan mudah.

o Dampak terhadap lingkungan tidak signifikan.

Perawatan, bagi organisasi yang baik, merupakan bagiandari tugas keseharian yang sudah melekat.

No established design manual for design of floating breakwater, as opposed to conventional breakwater.

Design of Floating Breakwater

Client and consultant will chose types and shape of floating breakwater to be explored further.

Chosen types and shapes will be investigated in physical hydraulic laboratory.

Elements of DesignDesign of Floating Breakwater

Type and shape.

Materials.

Anchor / tether system.

Installation method.

Risk.

Hazard mitigation.

Floating BreakwaterCost (initial + maintenance + risk management) to performance ratio.

Will be compared to conventional breakwater

Assisted by laboratory experiment

Laboratory Testing of Floating Breakwater

Side View of Wave Flume Credit to Ajiwibowo and Yuanita

End of Presentation.Thank you for your attention.