THE BERLIN IRON BRIDGE COMPANY,
FOR MANY years it has been the practice of engineers, when wishing a permanent bridge, to build a stone arch. Often stone
arches have been built over streams where they contract the water-way so much as to cause great damage, and sometimes the
bridge itself has been completely washed away. It is not always possible to get sufficient water-way for a stone arch, and it
becomes necessary to use an iron bridge. Many towns and cities object to iron bridges on account of the wooden floor which it is
necessary to renew occasionally, owing to decay and wear. After a large number of experiments during the past twenty years, we have
succeeded in designing an iron bridge which overcomes the objection to a stone arch, viz: narrowing the water-way, and at the same
time overcomes the great objection to any bridge with a wooden floor which will wear out. We have designed a bridge as shown in the
illustrations on pages 51, 53 and 55, which has no wood work about it in any part to wear out or to decay.
These bridges have now been in use in some places for over 15 years, without a single dollar being spent on them for repairs of any
kind. They are in every way equal in wearing and lasting properties to the stone arch, and we see no reason why they should not
practically last forever. The only possible objection to be urged, is that the iron work on the underside will occasionally require painting,
but as the corrugated iron arches which we use are heavily galvanized especially for this class of work, we see no reason why these
should not last indefinitely and never require painting.
These corrugated iron arches used by us are much superior to buckle plate, notwithstanding buckle plate is thicker, for the reason
that the vibration of the buckle plate tends to crack the concrete covering, and as soon as this cracks the bridge is ruined.
In the case of the corrugated iron arch we have no such vibration, and even if the corrugated iron arch should rust out in years, we
have a concrete arch remaining to carry the load of the bridge, which is amply sufficient.
For small concrete bridges, up to 25-foot spans, we place the stringers lengthways of the bridge, as shown on page 51, resting
directly upon the abutment. Between these stringers, and resting on the lower flange, we place corrugated iron arches, as shown in
the cross section, and above the arch we fill in with concrete, The beams are fastened across the bridge by wrought-iron rods secured
to the lower flanges, so as to keep the iron work in position while the concrete is being put in place. On the outside we put an
ornamental lattice railing, as shown, securely fastened to the outside girder. On the top of the concrete covering we put a wearing course
or pavement made of Trinidad asphalt.
EAST BERLIN, CONNECTICUT, U. S. A.