This is relatively short post, construction, or non equipment bridging uses construction materials rather than pre –manufactured equipment like a Bailey or Medium Girder Bridge.
As bridging equipment evolved, the need to use construction bridging techniques has lessened but it is still a subject that is taught to all combat engineers. As weights of vehicles increased the ability of these locally constructed bridges to carry those loads decreased and build times increased although in some operations there has been little alternatives.
The image below shows a very basic bridge over the River Narin in modern day Iraq.
Another example here, complete with cans of petrol should the Germans get close.
With the usual great video from British Pathe here
World War II operation in Burma for example, made considerable use of local building materials such as timber, bamboo and vines because Bailey or Floating Boat Equipment was in short supply.
Making do was the order of the day.
This image shows a construction bridge in Burma at the site of a large Bailey build but using local materials.
Even in later conflicts, non equipment bridging, especially in jungle terrain is the norm rather than the exception.
In 1982 in the Falklands the bridge between Fitzroy and Bluff Cove had been blow by the Argentine forces and was repaired by 9 Squadron Royal Engineers using locally obtained steel girders and timber.
More images here
Even in Afghanistan, non equipment bridging is still in use as this news story from the MoD shows;
Soldiers from 9 Parachute Squadron Royal Engineers (RE) carried out the repairs on the bridge after being alerted to the damage and resulting problems by soldiers from 2nd Battalion The Parachute Regiment (2 PARA), who regularly patrol the area. Following an initial assessment of the damage and the work required to make the crossing capable of carrying tractors once again, the necessary materials for the job were transported to nearby Checkpoint Perkha by the Paras. To do this, they made several journeys by quad bike – the only vehicle capable of getting through the series of narrow tracks running between irrigated fields. A team of six engineers, led by Lieutenant Keith McDougall, then began the task of building the new bridge. Firstly the abutments were shored up with pickets and corrugated iron sheeting, then a deck was constructed, consisting of timber baulks held together with a giant iron staple and resting on sandbags.
Returning back the beginning, this image shows that non equipment bridging does not have to be simple.
There are a small number of equipment’s that have endured in the building of ‘non equipment’ bridges, beyond the normal hand and power tools.
Developed in the inter war period, the Christchurch Crib is deceptively simple yet incredibly useful. It is nothing more than a skeletal steel construction used as a kind of Lego building block to form bridge supports, abutments and other devices.
Although the 3ft Bridging Crib had been used in WWI the evolved Christchurch Crib was not introduced until the mid-thirties. The Crib, properly known as the Bridging Crib 20 ton, was widely used in WWII in place of trestles and piers.
The key to their utility was their uniform dimensions and the ability to be joined together with simple bolts and nuts and used vertically or horizontally.
The 20 ton crib was developed further in the fifties to become the bridging Crib 50 Ton, but the design was essentially the same although there were some important differences such as being hot dipped galvanised instead of painted. Although they are interchangeable the position of the welds dictated which was up.
They were also used extensively to build water tank supports, especially for the common S Tank and Braithwaite tanks although cuplock scaffolding is now the norm.
Christchurch Cribs are still in service today, arguably one of the oldest pieces of military equipment still in service in their (more or less) original form.
An unusual use of the Christchurch Crib was in the construction of the prototype Harrier ski jump.
Sometimes called the Tirfor Winch, it is a uniquely useful piece of equipment, nothing more than a hand operated winch but its main feature is something it doesn’t do. Instead of drawing the steel wire onto a drum the Tirfor uses an opposed set of jaws to clamp directly onto the specially constructed wire rope.
The Tirfor can be used to pull, lift or apply tension when using appropriate anchors or block and tackle, without needing external power.
It has many uses outside bridging but when using a gin and shears to create a rope bridge it is used to tension the ropeway.
Click here for a brochure.
Tensioning the cables in any bridge construction is vital, especially rope bridges!
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