The task of modernizing the Verdun forts began in 1887 with Fort Douaumont, whose prime position protected the approaches to the city from the north and east and, in particular, from Metz. It was a gigantic task. The earth covering was first removed and the masonry was strengthened with pillars and concrete supports before being covered by a buffer of sand approximately one metre thick. Then, using for the first time a ‘continuous pour’ process, a thick layer of special concrete was poured on top of the sand. The eastern side of the barracks, some of the artillery bunkers and the tunnel into the barracks from the main entrance were covered with one and a half metres of concrete. The western side of the barracks and the remaining artillery bunkers, which were intended to form a strong ‘keep’ or redoubt for last ditch defence, received a covering two and a half metres thick. After completion, the whole of the concrete carapace was covered with a layer of earth between one and four metres deep. In 1888 a thick layer of special concrete was also applied to the open southern façade of the barracks. All in all, between April 1887 and November 1888 the work of strengthening Fort Douaumont required approximately 28,000 cubic metres of concrete and a team of some sixty construction workers.
To protect Fort Douaumont further, earth was banked up around the lower floor of the barrack block, covering it completely and effectively burying half the fort. The upper floor was now at ground level. To make the ditch less vulnerable to bombardment, the scarp wall was replaced by a sloping earth bank. To defend the ditch, strong, concrete galleries were constructed in the counterscarp, facing the fort itself. Armed with revolver guns and light cannon and later with searchlights, these galleries – single at the northern corners but double at the apex of the fort – were designed to sweep with enfilading fire any enemy who managed to penetrate into the ditch. Connected to the barracks by long underground tunnels, the counterscarp galleries could be reinforced regardless of enemy fire. The original gateway was scrapped and a new entrance – an independent blockhouse protected by double flanking galleries and a drawbridge – was constructed in the gorge (south) side of the fort. From the blockhouse a tunnel ran under the rampart to an entrance on the lower floor of the fort.
The armament of the fort
The original plan for the armament of Fort Douaumont had provided for twenty guns mounted on the parapet but the revolution in high explosives and artillery in the 1880s meant that henceforward guns had to be protected if they were to remain operational at all times. As a first step, ten of the guns were dispersed in batteries outside the fort but the introduction of steel-reinforced concrete in 1897 made it possible to construct shell proof gun positions in the fort itself.
The first protected guns at Fort Douaumont were installed in 1902-1903 in a new type of strong concrete bunker known, from the experimental range on which it was first tested, as a Bourges Casemate (Casemate de Bourges). Embedded in the southwest corner of the superstructure and shielded from direct fire by a long wall forming a protective wing, this bunker was strengthened with a layer of concrete almost two metres thick. It was armed with two quick-firing 75mm field guns installed in two chambers placed in echelon, whose embrasures allowed for fire in one direction only. The fixed guns, which had a range of 5,500 metres, were sited so as to cover the southwestern approach to the fort and to cover with flanking fire the defensive works situated along the ridge between Fort Douaumont and the Ouvrage de Froideterre. An observation post and magazines completed the installation.
The construction of the Bourges Casemate marked the beginning of the period that turned Fort Douaumont into a modern, armoured fort of enormous strength. Between 1902 and 1913, further armament was provided in the form of guns housed in retractable steel turrets of very advanced design which, by rotating through 360°, covered all the approaches to the fort. The turrets were activated by a vertical movement that raised them into the firing position and lowered them again once the gun had ceased firing. Raising the turret exposed the gun embrasures and allowed the guns inside to fire. When retracted, the guns were hidden from view and entirely protected by a steel dome which, in the case of the bigger turrets, was strong enough to withstand even direct hits by the heaviest shells. The turret was set in a reinforced concrete unit that also housed the activating machinery, magazine, replacement guns and range-finding equipment. Each one was coupled with an observation post protected by a dome of steel twenty-five centimetres thick and connected to the gun by speaking tube or telephone.
Four such turrets were installed in Fort Douaumont and linked to the barracks by underground tunnels. Two lighter models housed twin eight millimetre Hotchkiss machine guns that were mounted one above the other and fired alternately to avoid overheating. Intended for the close defence of the fort, the machine guns were installed at the northeast and northwest corners of the superstructure where the visibility was best. On the eastern side of the fort a short-barrelled 155mm gun capable of firing three rounds a minute over a range of 7,500 metres protected the vital north and northeast fronts. An armoured observation post at the entrance to the turret communicated with it through a speaking tube while another some distance away communicated with the gun crew by telephone. Twin short-barrelled 75mm guns housed in a similar turret in the escarpment to the north completed the armament. The 75mm guns, which together were capable of firing more than twenty two rounds a minute over a range of 5,500 metres, were intended to sweep the intervals between the forts. Their considerable firepower more than compensated for the dispersion of the remainder of the fort’s artillery in external batteries. By 1913, all the gun turrets, observation posts and the Bourges Casemate had been linked to the barrack block by strong underground passages so that they could be accessed at all times without going outside.
Mighty though it was, Fort Douaumont formed only one element in a strong and extensive ‘centre of resistance’ which also included Douaumont village, six ouvrages, five combat shelters, six concrete batteries, an underground shelter for reserves, two ammunition depots and a whole series of concrete infantry entrenchments. A revolving turret for twin 155s on the slopes to the south of the fort and another for a 75mm gun on the ridge to the east should have completed the defence but neither emplacement was complete when war broke out. A machine gun was mounted in the observation post on the ridge, while the incomplete 75mm gun turret became a shelter.
Access to the fort
Fort Douaumont was an immense structure, measuring almost 300 metres from north to south and 400 metres from east to west. It was protected on all sides by an open glacis offering wide fields of fire in every direction and surrounded by a belt of wire thirty metres deep, which was attached to metal picket posts set in concrete. At the top of the glacis, a line of stout spiked railings two and a half metres high ran along the counterscarp. On the floor of the ditch – approximately six metres below the top of the counterscarp – a further line of railings was set at an angle along the base of the scarp. The outer wall of the ditch was strengthened by a facing of masonry on three sides of the fort, but on the south side, where the inner wall was strengthened and provided with flanking blockhouses, it consisted of only a bank of earth.
The fort was accessed by means of a wagon road that led up the glacis on the south side of the fort, passed a guard house and came down in the ditch close to the main entrance or ‘peacetime gate’. The road then ran across a drawbridge and entered a tunnel under the rampart. This led to the ‘wartime gate’, which allowed direct entry to the lower floor of the barracks. At the end of the tunnel, two ramps provided access to the upper floor of the barracks and to the covered wagon roads that passed through the barrack block at each end. Emerging from the barracks on the north side, the wagon roads became the Rue du Rempart, which served the adjoining artillery shelters and ammunition depots. Access to the fort on foot was also possible by means of steps cut into the rampart, which led to a footbridge spanning the gap between the tunnel and the wartime gate. On the top of the rampart, two light steel domes allowed for observation over the south side of the fort
The barrack block was a two storey building. The lower floor, known as the ‘wartime barracks’, comprised the fort’s administrative services, siege headquarters for the commandant and his staff, depots, magazines and two groups of cisterns each holding 520 cubic metres of water. The upper floor, or ‘peacetime barracks’, provided accommodation for the garrison of 850, workshops, magazines and kitchens as well as a bakery and an infirmary. Staircases or metal ladders linked the two floors and on each level the barrack rooms opened onto a principal corridor. On the upper floor the corridor ran throughout the whole length of the barracks and joined the covered wagon roads at either end of the building.
One year before the outbreak of the war, Fort Douaumont was complete. The strongest and most modern of all the forts around Verdun, it was the cornerstone of the whole defensive system. Its construction, modernization and armament had required a total of twenty eight years and had cost 6,100,000 gold francs.
As early as September 1914, Fort Douaumont’s 155mm gun was in action against German positions to the north of the sector. The Germans soon replied with a barrage of medium and heavy calibre shells that caused some slight damage but left the fort’s vital organs unscathed. The operation was observed by a prominent guest, Crown Prince Wilhelm of Germany, who had been invited by the commander of V Reserve Corps, General Erich von Gündell, to view the shooting from his newly built observation tower, the ‘Gündell-Turm’. The French were not impressed and the tower soon became a favourite target of French gunners.
In December 1914 the 155mm gun was again in action, this time against the Jumelles d’Ornes, two hills that formed an important German observation post to the northeast of the sector. That brought retaliation from the Germans in February 1915 in the form of a ‘shooting match’ (Wettschiessen) between two of their biggest guns – a 420mm Krupp mortar and a 380mm ‘Long Max’ naval gun – during which thirty four huge projectiles were hurled against the fort and its immediate surroundings. Despite a great column of smoke which rose above the glacis and at first led the Germans to believe that the fort had been put out of action, only limited damage was done. On the eastern side of the barracks where the concrete carapace was only one and a half metres thick, three shells falling close together brought down the roof of the bakery and a nearby corridor, while the blast from a fourth fissured the floor and walls of the gallery leading to the 75mm turret. The guns, however, were unharmed. One 420mm shell striking the reinforced concrete collar of the 155mm turret left a deep hole but only slightly affected the turret mechanism and repairs were carried out within a day or two. Another fell without exploding close to the Rue du Rempart, where it was defused and sent to Paris for exhibition.
The fact that such a shell had hit the concrete covering of the fort and failed to explode probably encouraged the French High Command in its comfortable belief that the most powerful of the forts around Verdun was impregnable. Indeed, had the whole mighty system not been disarmed in the second year of the war, that belief might well have proved correct.