A History of Research and a Review of Recent Developments

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Response, safety and evolution
The great military engineers of the time developed the ‘star’ fortress, with
five or six bastions each shaped in plan like the ace of spades, so that the
defenders’ artillery could ward off the assault forces and at the same time give
covering fire to adjacent bastions. However, as we saw earlier in the
Introduction, the dominance of this form was threatened in the seventeenth
century by systematic methods of attack developed by Vauban. He developed
fortress designs to withstand the new attack methods, and thus became the
outstanding figure in both siegecraft and in fortress defence of his time. It has
been said that a fortress built by Vauban was impregnable, and that one besieged
by him was doomed. His contribution has been discussed by Harris [9.1].
By the early years of the twentieth century concrete began to be used in
increasing quantities, and concrete roofs of 2 or 3 metres thick were built over
revetments. Major cities in Europe were ringed with fortresses and in the
years leading to the outbreak of the First World War the ideas of the Frenchman
Brialmont were used in the construction of defensive systems. He used steel
armour to protect guns, and devised retractable cupolas and turrets; his ideas
were used by the French in developing their fortress system along the German
frontier.
Reinforced concrete now became the standard material for protective
structures, and was used in conjunction with the application of ballistics to
the design of fortifications. Individual forts were often triangular in plan, and
by 1914 the Brialmont system had been used to build this type of fort at
Antwerp, Namur and Liege in Belgium. At the beginning of the First World
War the Germans attacked through Belgium, using the Krupp 420 mm Howitzer.
Liege fell in eleven days, Namur in four and Antwerp in ten, and apart from
the success of the fortress of Verdun as a very strong point in the battle of the
Marne, it was generally concluded at the end of the war that the cost of the
fortifications was not justified.
In spite of this, as the Second World War approached, the French built the
celebrated but ill-starred Maginot line, the Germans built the Siegfried line,
and the Russians the Stalin line. On the Dutch/Belgian border a fort very
similar to the Maginot line design was built to dominate the River Meuse. It
was thought to be impregnable. On 10 May 1940 this fortress was apparently
taken in a few hours by less than one hundred German glider-borne engineers.
They are said to have landed directly on top of the fortifications and used new
shaped hollow charges to blast into the cupolas, although the accuracy of this
report has been questioned. After the breakthrough the Maginot line was
outflanked, and the huge construction of mutually supporting positions
stretching from Luxembourg to Switzerland, which involved 100 kilometres
of tunnels, 12 million cubic metres of earthworks, 1.5 million cubic metres of
concrete and 150 000 tonnes of steel, was of no value. The fortifications have
been described by Taylor [9.2].
In the period since the Second World War there has been a change in the
protective structure requirements of military operations, brought about by