FOOTBRIDGE BUILT BY ENGINEERS ACROSS CANAL DE L'EST NEAR THE VILLAGE OF BRIEULLES, FRANCE.
This bridge was constructed under heavy fire from enemy guns.
Meanwhile the efforts of the Engineers were being directed to the development of standard ponton equipment strong enough to carry tanks and the ponderous artillery of the present day. The old ponton bridge was first strengthened to carry loads of 5 tons on each of two axles spaced 10 feet or more apart. The standard prewar equipment would support only 3 tons similarly spaced.
The next step was to develop a bridge that would hold up axle loads of 10 tons with a distance of 12 feet or more between axles, although in actual use this bridge showed itself capable of supporting a load of 15 tons concentrated on one axle. As soon as these developments were made, the plans were mailed to the American Expeditionary Forces, so that the Engineer Corps abroad could provide the beams and metal parts at its own mills and shops in France. When the fighting ceased, the Engineers were designing a raft capable of transporting the heaviest portable ordnance then under manufacture in the United States.
In 1917 the Engineer Department made designs for a standard sectional steel bridge, consisting of short latticed steel truss sections capable of being assembled to form trusses varying by increments of 11 feet up to a maximum span of about 90 feet. Two of these trusses with the span mentioned were capable of supporting a load of 30 tons, and they could be erected in a matter of hours over abutments prepared in advance or extemporized from the ruins of a demolished structure. These bridges had been manufactured in quantity in this country and were ready for shipment when the armistice was signed.
In the Argonne push Army bridge troops repaired and replaced the bridges destroyed by the retreating enemy as fast as material and labor could be provided at the points needed. For this work much heavy timber was utilized, and, in general, trestle structures were erected as best meeting the conditions of relatively soft crossings and soft river bottoms.
The fighting in the French terrain with its numerous narrow but deep streams and canals indicated to us the desirability of a portable floating footbridge. Such a bridge was designed and produced by the Engineers in France. Many of the crossings of the Meuse River and near-by canals under machine-gun and artillery fire from the high hills on the eastern side were made possible by the use of these bridges.
CAMOUFLAGE.
While camouflage has existed in nature since the beginning of time, its application to warfare on a grand, scientific scale was almost solely a development of the great war. Camouflage, due to the great developments of aerial observation and aerophotography, as well as of air bombing and indirect artillery fire, became a vital necessity for every branch of the service, far back in the rear as well as at the front. Any matériel or personnel the position of which was observed was at the mercy of the enemy, but, further, such observation might betray strategic plans. The need for camouflage became universal.