Bomvrij militair object, Werk aan de Groeneweg

English translation

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Description

Cluster 62. Group shelters type P.

NEW HOLLANDSE WATERLINIE Introduction

GROUP SHELTERS TYPE P as part of linear and access defence with trench systems, casemates and the like. Within the Werk aan Groeneweg numerous group shelters Type P are located. Of the still existing specimens, most were created in linear arrangement, the majority of which are situated on the front side or east side of the existing defence line with group shelters types 1918/I and 1918/II. Of any former earthwork, wooden or concrete structures, such as covered roads, trenches and the like, little or nothing remains recognisable on the surface. An unknown number of specimens of group shelters type P in this complex have been lost over the years through dyke relocation, settlement expansion and the like.

(Concrete) group shelters were a response to the arrival of heavy projectiles and explosive grenades. The latter carry a high-explosive charge. According to the weight of the grenade and the protection against it, a classification in resistance or protection classes has existed since 1928, consisting of two numbers, for example W 12-15. The first indicates that the protection is sufficient for impacts of projectiles up to that calibre (in cm); the second that protection also exists against one or at most a few impacts up to this higher calibre. The earliest types of group shelters offered only protection against grenade fragments and were called 'shrapnel-proof'. Group shelters type P were, according to a more or less uniform or standard design, built in multiple locations in the Netherlands especially in the years 1939-1940. The total number of built specimens amounts to approximately 700, of which around 570 in the Nieuwe Hollandse Waterlinie; the majority (approximately 400) of these still exist. The construction programme of the Type P shelters was not completed by the outbreak of the Second World War and a number of specimens remain visibly unfinished. Type P (also called 'the pyramid' because of its distinctive shape) is presumably the best-known type of concrete defence work in the Netherlands. The type derived from the so-called VIS 77 (Regulation for Establishing Positions no. 77), from 1928, and had among other purposes the aim of forming part of the defence of a number of existing and newly realised accesses, including in particular (motorway) roads. The group shelter Type P usually came into being in the immediate vicinity of existing or contemporaneously realised casemates, gun emplacements, fortifications or trenches. Because the trenches and other earthworks were later levelled almost everywhere, the concrete shelters nowadays sometimes lie partly below ground level. The originally completely closed front or frontal side of the group shelters Type P was intended to be covered by earthworks, which could form part of a glacis for protection of the trench or a covered road. These earthworks are now mostly no longer present or barely recognisable, but particularly on forts or in terrain otherwise characterised by relief there is sometimes still coverage. Various variants of Type P exist, both in terms of dimensions and protection class as in execution and detailing. For example, specimens were built in the protection classes W 15-21 and W 21-28 with dimensions ranging from approximately 5.50 x 7.20 x 4.70 m to 6.50 x 8.20 x 4.90 m (w x d x h). Numerous specimens of Type P were built in inundatable areas, in a number of cases with a (later visible) pile foundation, while often a retaining wall and occasionally a trough with stairs against inundation water was incorporated in the then elevated, square access. In yet other variants of type P a concrete foundation slab projecting all around is present.

Description

GROUP SHELTERS TYPE P are single-storey, usually reinforced, approximately 100 to 180 cm thick cast concrete, splinter-proof, military shelters, which could provide protection for 10-12 infantrymen / artillerymen. On the access of the Houtense Vlakte and the Kromme Rijn most group shelters type P belong to the heaviest class. The group shelters Type P were built on a rectangular ground plan. The visible height above ground level varies; this is also a consequence of the fact that not all specimens are completed. Both blind side walls and the rear side are executed vertically up to approximately 3 m in height. Above this these walls slope inward at approximately 45° before passing into a flat roof. On the right in the rear side is an access opening at locally varying height above ground level, later either closed off or left open. The entirely vertical, closed front side reflects the 45° angles and thus ends as a 'truncated pointed gable'. In a number of cases iron hooks or brackets were cast into the facade(s) which could serve for attachment of camouflage material. A characteristic component on top of the shelter type P is the conical concrete 'outlet', which was intended for the use of a periscope. These periscopes were never actually installed in practice. The interior of the group shelters Type P consists of a short passage (usually with a concrete retaining wall or balustrade and generally a few descending steps) and from there a 'sluice' directed to the left which could be barred by a (consisting of several parts) heavy, steel door with bolts. Via a second, similar door a rear, almost square room could be reached to the right, the actual shelter. The entrance could be covered by loophole fire from this room. The steel doors are often no longer present outside of the terrain still used by Defence even after the Second World War, or they are invisible as a result of the sealing off of the group shelters with brick or concrete. The ceilings located at approximately two metres above floor level are flat and rectangular. In a number of cases interior components are still present, such as (remains of) wooden benches or a support for a hand firearm for covering the entrance. Most specimens within the complex Werk aan de Groeneweg lie clearly recognisable in the field - in a number of cases in a fairly disturbed context - but some stand in difficult of access or poorly recognisable places, such as in gardens, and in vulnerable places, such as in the floodplains of the Lek.

Valuation

The GROUP SHELTERS TYPE P of the Werk aan de Groeneweg are of general importance because of:

* Cultural-historical values as part of the Nieuwe Hollandse Waterlinie as designed by C.R.T. Kraijenhoff and initially from 1815 realised by him, Jan Blanken and major-engineer Willem Offerhaus and subsequently strengthened and improved by others for approximately 125 years.

* Architectural-historical values, in particular as an expression of military-strategic building, which is based on the system of: a. the system of inundation and access defence (20th century), b. the race with increasingly strong offensive means (20th century), c. the system of 'living' field fortification in depth (20th century).

These are components from the period 1939-1940, namely dozens of group shelters of type P (pyramid).

* Ensemble value and situational values as part of the Nieuwe Hollandse Waterlinie in general and because of the mutual functional, functionally-spatial and physical coherence with the remaining components of the complex.

* The components are representative (characteristic) because they have been preserved in large numbers and clearly recognisable in the field.

* The components are reasonably well preserved because the principal physical characteristics have remained recognisable.