Tímarit Verkfræðingafélags Íslands - 01.05.1922, Blaðsíða 18

40
TÍMARIT V. F. I. 1922.
should be filled up, and a protecting mole built
from there with a mole-head at 5 m water. The
top to be 3 m wide and 5,5 m above low-water level.
Along the outer end of the mole should be built a
quay-wall, 30 m long, of concrete sinking-blocks.
Along the inner side of the mole should be con-
structed a quay-wall of 30 m length for the use of
smaller vessels at high-water. A boat-bridge should
also be built from the south-eastern corner of the
filling-up. The total cost of these constructions is
estimated at about Kr. 1,064,000.
4 5. Hellissandur, map XVII. Hellissand-
ur is lying nearer to the fishing-banks than Ólafs-
vík, but the natural conditions are not so favour-
able, nor will it be possible for the same cost to
procure as good a harbour. A protecting mole as
shown on map XVII, top 4 m wide, inclining 1: 1
and 1: 2, will cost about 1 million Kr., not including
construction of quays etc.
4 6. S t a p i. The natural conditions are unfavour-
able for harbour constructions, the fore-shore is
very narrow with steep rocks behind it, and the
depth of the water outside the place increases very
quickly. The cost of harbour constructions would
be too high in comparison with the advantages
gained.
4 7. B ú ð i r. Búðir is lying at the mouth of a
small river. The approach is difficult, the landing-
bridge is dry at low-water, and on the whole there
is very little water in the river. The waters out-
side the mouth of the river are also difficult, and
the place cannot therefore be considered to be fa-
vourable for harbour constructions.
VII. The Faxe-Bay (the northern part).
4 8. Borgarnes, map XVIII. This is a fair-
ly large trading-station with a considerable through-
going trafic between Reykjavík and the northern
and western part of Iceland, and a large export of
agricultural produce. The firth, Borgarfjörður, is
broad, but full of rocks and very shallow. The en-
trance is winding and so shallow that even srnall
steamers cannot pass at low tide. There is no quay,
and at low tide the work cannot be carried out
with lighters, as the existing bridges are not long
enough. The difficulties are further increased by
the strong current, and in winter by floating ice
from the large river, Ilvítá, which has its outlet in
the firth. On account of the importance of the
place it is, however, greatly to be desired that the
prevailing conditions should be improved upon. Mr.
Kirk has, therefore, sketched the constructions
shown on plan XVIII. These consist of a jetty or a
bridge across Brákar-Sound, a landing-bridge on
the south-western side of Great Brákar-Island with
a swinging-place deepened to minus 3 m, and the
deepening of an entrance-canal to 3 m at low-tide.
It will have to be examined whether it is possible
to carry out this deepening all the way, but if the
rocks do not prevent the deepening, the cost of
these constructions is estimated to come to about
Kr. 130,000. In this amount is included the con-
struction of a jetty across Brákar-Sound, if an
arched bridge of concrete is built the cost will be
increased with about Kr. 70,000.
4 9. Akranes, map XIX. Akranes is an im-
portant fishing-place, but the conditions are unfa-
vourable, and it will not be possible to improve them
to any very useful extent. The anchor-place for the
fishing vessels is at Krossvík, where there is a
landing-bridge, but when gales are blowing straight
from the sea, vessels cannot lie here. Another small
creek, „Lambhússund“, is therefore generally used,
as it is safe, being protected by rocks in the sea,
but the entrance is very difficult and in storm im-
possible. Careful soundings show that the bottom
of the creek is so full of rocks and shoals that it
is impossible to improve the conditions. The only
construction which it would be possible to make is
to build on the reef „Vestur Flös“ on the north-
western side of the creek. The top-edge of the reef
is almost in the high-water line, but in a couple
of places it is cut through to about 2 m over low-
water line. A wall of concrete, 5 m above low-
water level (1 m above high-water) would give
bettei' cover for the creek, and it would protect the
reef which seems to decrease during later years.
The cost of constnicting such a wall of concrete
would be about Kr. 35,000.
With regard to the estimates the following wages
and cost of material have been used as basis for the
calculation:
laying lai'ge stones . . Kr. 8—15 per cubic m
filling-up with gravel
and small stones . . — 4,00 — —
brickwork . . .
concrete ....
reinforced concrete
regulating stones.
timber...........
iron.............
cement . . .
— 60—80— — -
_80 — — -
— 250—300
— 8,00 per square m
— 200—250 per cubic m
— 800 per ton
— 40 per barrel.
Mr. Krabbe points out that, as prices have been
falling since the calculations were made, the esti-
mated costs must be accepted with great reserva-
tion, and are in reality only of interest in comparing
the various constructions.
-o-