DESIGN OF BREAKWATERS - · PDF fileNorth Alsukhna Port Breakwaters ... Requirements: quay facilities (access, warehouses, sheds) ... R.C. Wall (caisson)

Design of Breakwaters

BY Dr. Nagi M. Abdelhamid

Department of Irrigation and Hydraulics

Faculty of Engineering

Cairo University

2013

Purpose for construction Breakwater A breakwater is a structure made of natural

stone or concrete elements which gives

shelter to a shoreline, harbour, anchorage, or

basin from the direct impact of incoming

waves.

To provide a safe, suitable accommodation for

ship refuge, supplies and transfer of cargo.

Protected navigation channel

Prevent deposition in entrance channel

Prevent erosion inside the harbour

2 Dr. Nagi Abdelhamid

Breakwater design

Port Said East Port

Breakwaters - Problem definition


Breakwater design

Port Said Port



Breakwater design

Alexandria Port



Breakwater design

North Alsukhna Port



Breakwater design

Tartous Syria



Breakwater design

Shinas port Oman



Breakwater design

Marina at Beirut



Breakwater design

Port and Marina at Beirut



Breakwater design

Requirement: limit overtopping and transmission

Dr. Nagi Abdelhamid

Breakwater design

11

Requirements: acces (harbour workers, traffic, oil piping)


Dr. Nagi Abdelhamid

Breakwater design

12

Requirements: quay facilities (access, warehouses, sheds)


Durres Port (Albania)


San Stefano Marina and Private beach 13 Dr. Nagi Abdelhamid

Breakwater design

Breakwater Types

1- Permenent breakwater Rubble Mound Breakwaters

Vertical Wall Breakwaters

Vertical composite type

2- Temporary breakwater Peneumatic and hydraulic breakwater

Floating Breakwaters


Breakwater design

Permanent breakwater

Rubble mound and vertical breakwaters.

.

Rubble mound breakwater Vertical composite type

breakwater

Vertical type breakwater 15 Dr. Nagi Abdelhamid

Breakwater design

Rubble Mound Breakwater


Breakwater design

A rubble mound breakwater normally

consists of a core of small size rock covered

with large [heavy] rocks or concrete

elements. This outer layer is called the

armour layer. An under-layer of rock is

provided between the core and the armour

layer.

Outside layer large enough to resist wave

action.

Inside layer small enough to prevent

removal of native fine material in between.

Rubble mound breakwater


Breakwater design

Advantages of Rubble mound breakwater:

Failure of the armour layer is not sudden

but gradually;

It allows high energy dissipation due to its

slope and transmission through porous of

mound;

It can be used for weak soil;

Easy maintenance and construction;

Small wave reflection;

Minimum overtopping less than Vertical

Breakwater.


Breakwater design

Rubble Mound Breakwater

breakwater types Advantages Disadvantages

Rubble mound breakwater

1- Suitable for irregular bottom 1- Required material increases rapidly with increased water depth

2-Suitable for weak soil (distributed load) 2- High maintenance cost

3- Progressive damage 3- Large base cuts into basin area

4- Low toe scour

5-Simpler construction

6-Simpler maintenance


Breakwater design

Cross sections of the breakwater


Breakwater design

Vertical Wall Breakwaters - Types

breakwaters with vertical

concrete block

breakwater types Advantages Disadvantages

vertical breakwater

1- Material savings 1-Requireds firm Soil

2-control water depth clearly defined

2- High Construction requirements

3-Repair difficult

breakwaters with vertical

R.C. Wall (caisson)


Breakwater design

Composite Breakwaters

concrete superstructure founded on a rubble substructure.

composite breakwater

1- Suitable for deeper water with less firm soil

1- More Complicated construction

2- More Susceptible to breaking waves

The caisson ( or concrete blocks) is placed on a high

rubble foundation.


Breakwater design


TYPES (continued)

• Semi-circular caisson Well suited for shallow water

situations with intensive

wave breaking

Due to the dissipation of

energy both the wave forces

on the caisson and the wave

reflection are reduced


Breakwater design


• Perforated front wall

Dr. Nagi Abdelhamid

Breakwater design

24

Dieppe (France)

The front wall is perforated by

holes or slots with a wave

chamber behind.

Due to the dissipation of energy

both the wave forces on the

caisson and the wave reflection

are reduced

Documents

DESIGN OF BREAKWATERS - · PDF fileNorth Alsukhna Port Breakwaters ... Requirements: quay facilities (access, warehouses, sheds) ... R.C. Wall (caisson)