The heaviest wear on a bridge is usually the deck boards.
On site over hung with trees the deck boards may build up wet debris and rot if they are not maintained.
When the boards become a concern, some folk replace the bridge, but a more economical solution is to replace the deck boards.
We can supply deck boards to match whatever you have but often supply more satisfactory boards than the originals. Grooved, tanalised boards are standard and we can supply boards with a variety of anti-slip treatments.
The most common are in Softwood but we also supply hardwood (both ekki and o... Read More
Kerbs on bridges
When operating any kind of wheeled vehicle on a bridge deck it is prudent to fit kerbs
These are continuous raised edges to the deck to “train” wheels and prevent them from inadvertently leaving the bridge.
The kerbs will also protect the parapet from damage by the vehicle.
In the image above a particularly wet site required a drainage gap under the kerb and it has been integrated in the parapet. This is only possible in this case because the parapet is made from a very strong hardwood. If it was softwood it might seriously damage the parapet due any impact. Read More
What is Ekki?
Ekki is the most popular hardwood used for making bridges.
It comes from The Gabon in West Africa but is usually sourced via Holland. A Francophone nation – interesting fusion of African and French cultures!
It is a Tropical Hardwood. It is however grown in accordance with the Forestry Stewardship Council processes and is FSC Certified.
There are ethical issues to do with the carbon used to deliver the material to Europe. The oil used in marine transportation is the dirtiest and most polluting – used by shippers because it is cheap.
It is suspected that virgin f... Read More
What are the best fixings for wooden deck boards?
What are the best fixings for wooden deck boards?
When fixing Deck Boards we need to ensure they are securely fastened down and that they cannot be easily removed by vandals.
However we also need to make it possible for the deck boards to be lifted (by authorized people) in order to inspect the bridge at regular intervals and if necessary to be able to repair or maintain it.
Wooden deck boards are invariably fastened to timber. This will either be wooden beams or wooden Stringers fastened to the top of steel beams. It is important that these stringers are not damaged by the fixing.... Read More
On scaffolds, on building sites, kick boards are quite rightly mandatory. They prevent tools or materials being knocked off to fall on people working below.
When bridges cross rivers this is not relevant
When bridges cross other paths it is good practice but is not always observed.
If the kick board is in direct contact with the deck it will trap debris. Soil will build up and plants establish. The combined effect will keep the wood permanently wet and the life of the timber will be reduced,
On equestrian bridges The British Horse Society recommends high kick boards -&n... Read More
Anti Slip Treatment
Bridge users regularly slip when surveying older bridges. It is only their agility which saves the day
Leaf litter, algal growth, dog-mess and dampness can reduce untreated decks to an ice rink. Especially on hardwood decks.
The introduction of grooving was a great help
Clearly grooves are only effective if they are not over laid with litter,
As anti slip treatments became available the question of the most effective use of it arose. In the first instance the material was spread across the entire surface and before it cured aggregate was sprinkled onto it.
Handling t... Read More
What is cladding on a bridge?
Occasionally we are asked to make a bridge with steel beams look like a timber one.
It Surprises us how people feel galvanized steel finish is out of place in the countryside. virtually every field gate and kissing gate is galvanized.
We don't have these feelings as Engineers.
Ever eager to supply what our clients want, we naturally conceal the beams. This process is called cladding.
in order to inspect the bridge, the cladding needs to be capable of being removed.
This can be a costly process involving scaffolds and the disturbance of wildlife (bats).
B... Read More
Steel and Timber Bridges
The name of our firm is misleading!
We are one of the major supliers of bridges with steel beams
As bridges get longer the use of timber beams becomes an issue
The stiffness is achived as the span increses, by increseing the thickness of the beams and/or incresing the depth of the beams.
The beams get huge and are difficult for our kit bridge useres to manage on site.
our prefered installers mutter darkly when given bridges with huge beams.
In softwood we run into 3 issues.
Fi... Read More
Two kinds of timber is commonly used by bridge engineers. Softwood and Hardwood.
Softwood is more economical. It comes form Scandinavia and the Baltic States. It is farmed there on a massive scale and absorbes huge amounts of carbon.
The two most common species used are Douglas Fir and Redwood. Douglas Fir is stronger and has a natural preservative in it. Redwood is used for the parts which come into contact with the user as it planes up better than the Douglas Fir.
All our softwood is stress grades C24 and it is all tanalised after machining to maximise its life.... Read More
It is simply wrong to delberately place plastics in the environment. Paticularly those places we need to keep un poluted. They will eventually break down and perneantly degrade our world.
Some misguided people believe it is "green" to use recycled plastic instead of timber for access provision. We are actually using our special places as a store for waste plastic
It uses lots of energy and more polymer to convert the waste into a "usable" form. In this form it is variable in quality and performance.
Laughably these recyced plastics are much more expensive... Read More