As the Boer War drew to a close most of the Royal Engineer units returned to the UK and a period of re-organisation followed that culminated in the formation of three bridging Companies, allocation of Field Companies to Divisions and additional units to take responsibility for searchlights, air, works and telegraph signals.
A number of additional organisational recommendations were made before 1914 but many of these were not implemented before the outbreak of war.
Pontoons, trestle bridges and rafting equipment were the main equipment held but construction bridging was also a large part of the RE repertoire. Lord Haldane ensured that the British Army of 1914 was probably as best prepared for conflict as any but bridging equipment and the Corps was arguably not prepared for the nature and duration of what was to follow for the next 4 years.
Rapid expansion of course followed, at its peak, the Corps was over a quarter of a million men.
It was during this period that it became obvious that time consuming construction bridging was impractical and the majority of gaps to be crossed were not suited to floating or pontoon bridges. Thus came to the fore, equipment bridging; stock spans, canal bridges, the Hopkins Bridge and the Inglis Bridge (the forerunner of the Bailey Bridge) were all developed during this period.
With the introduction of the tank, the need for assault bridging also became apparent and rapid advances were also made in this area.
Europe
One might not immediately envisage static trench warfare having a great deal of need for bridging, the majority of engineer tasks were fortification, infrastructure, tunnelling and the myriad of other duties that the Royal Engineers had, let’s not forget the Royal Engineers were the birthplace of the modern RAF, REME and Signals.
For an extensive look at the Royal Engineers in the Great War click here
During the initial German advance and retreat, as positions stabilised, there were a number of bridging operations including the famous Pont des Anglais. The crossing over the River Aigne was called the Pont Saint Waast and this was destroyed by German forces as they retreated on September 13th 1914.
During the following days a number of pontoon bridges were constructed and the main crossing at Sousson finished on the 1st of October. The bridge in question was designed and constructed under the supervision of the commander of 9 Field Company, consisting of locally available materials including floorboards from the local houses!
The bridge was subsequently named the Pont des Anglais, a name which is still used today.
The 1933 account of Military Operations in France and Belgium 1914 written by Brigadier-General Sir James E. Edmonds described the efforts of the bridge builders as such;
A wooden girder bridge to replace the broken span of the existing bridge was begun at Soissons on the 1st October and completed on the 9th. It was then handed over to the French, as the British were leaving the locality; it was known hereafter as the “Pont des Anglais,” (The permanent bridge built after the war perpetuates the name.) and was in use continuously until destroyed in the German offensive in 1918. In addition to all these bridges, barges equipped with roadway were prepared, ready to be swung instantly across the river to form additional bridges if required.
This bald enumeration, however, gives but a slight idea of the strain borne by the engineers during the weeks that the Army was on the Aisne. Nearly all of the bridges were within known range of the German guns; most of them were constructed, and at different times all of them repaired, under fire. At Vailly, where a permanent bridge was much needed, the German shells prevented even attempts to build one. The rise of the water necessitated frequent changes and modifications of level; and the incessant rain made the task of keeping the approaches in order most difficult and trying. Yet the engineers contrived not only to maintain the bridges, but to make bridgeheads and to entrench positions against the possibility of a retreat. In the course of the operations on the Aisne, the divisional Field Companies R.E. which had done the work were reinforced by the 1st and 2nd Bridging Trains, and by the 20th and 42nd Fortress Companies from the Line of Communications; but even with this assistance the burden of work thrown upon them was very heavy.
It was also reported that the Chief Engineer of III Corps was seen hanging on a rope at one stage, such was the maximum effort required.
Another crossing point is shown in the image below.
The Somme offensive of 1916/7 was the next major phase in bridging operations; the majority of the initial operations were confined to improving lines of communication to enable the huge volume of stores to be brought forward in preparation.
During the offensive the Germans commenced a withdrawal back to the Hindenburg Line and during their movements destroyed all the bridges across the Somme and a number of canal bridges.
Click here for a map.
The Field Companies from 1 Division were given the job and despite all stores having to be carried forward by horse because of the state of the roads would not support trucks construction commenced in short order. 6 heavy bridges were completed ahead of schedule.
Although equipment bridging was not carried out on the same scale as in WWII there were still over 60 bridges completed any many were successively improved to take extra weight, especially with the advent of the tank.
The final stages of the war, where battles were less static, saw the pace of bridging activity markedly increase; over 300 heavy equipment bridges and 200 timber bridges had been constructed.
The final advance of 1918 saw increasing use of the new Inglis Bridge and in particular the ability to rapidly erect and dismantle this type of bridge provided a glimpse into the future and the Bailey Bridge.
Although the advance saw many bridging operations carried out by British, Canadian, New Zealand and other Commonwealth nations engineers one of particular note was the crossing of the Canal du Nord in October 1918 by New Zealand and British engineers at the Hermies-Havrincourt Road.
Designed to link the Canal de La Somme at Peronne and Canal de La Sensée, Canal du Nord was still under construction at the outbreak of hostilities and the Germans would use much of the uncompleted works as part of their defences, some parts were flooded and others were not.
The image below shows an RE bridging party on the canal near Moeuvres in September 1918.
The most notable bridge though was elsewhere on the canal, the Hermies to Havrincourt Road goes over a deep cut. The image below shows the site before the arch bridge was destroyed, although later pictures show the canal bed was devoid of water and the actual bridging site was a little South as clear in the images later in this post.
https://www.flickr.com/photos/73614187@N03/6996187106/
https://www.flickr.com/photos/73614187@N03/6996184292/
There are a couple of good images of the cutting and bridge here
The final offensive needed the bridge across the canal at this location and the combined New Zealand and British force of engineers used large Hopkins bridge, which at the time was the longest bridge available. The slight problem was that the bridge had a maximum span of 120feet and the gap was just over 180ft, 85ft in the air. Building piers was out of the question so two bridges were joined, something that was easier said than done.
Working in two shifts the engineers constructed wooden towers on the East side to pull the bridge over the gap from the West side using cables and ropes that would also support the free floating bridge. A 20 tonne counter weight was also used to lessen the strain on the ropes and towers but because the weight was greater than normal because of the extended span there were several during the construction. Despite these problems the bridge was ready for trafficking only a few days after construction.
On the site today are a pair of one way bridges.
https://www.flickr.com/photos/73614187@N03/7142273377/
The bridging party consisted of 14 officers and 310 men from the New Zealand Tunnelling Company, 565 and 577 Army Troop Companies Royal Engineers.
There is a dedicated website for the New Zealand Tunnelling Company that is well worth a visit, click here
The Middle East
Whilst it is easy to forget anywhere but North West Europe when discussing WWI it should be remembered that the conflict touched many other parts of the world and the need for bridging was just as apparent. Italy, Palestine, Egypt and Iraq all saw significant bridging operations.
An interesting one was a steel girder bridge over the River Jordan, actually completed just after the Armistice and called the Allenby Bridge, but which saw daily use until it was destroyed in 1946, it was however replaced with a Bailey Bridge until repaired.
https://www.flickr.com/photos/73614187@N03/6996194376/
The repaired bridge was destroyed, properly this time, in 1967 by Jordanian engineers during the 6 Days War.
Many bridges were built in Mesopotamia (modern day Iraq) up and down the Euphrates and Tigris Rivers.
Think Defence 
