Schuilplaats, Fort bij Tienhoven Tienhoven (Stichtse Vecht 26)

English translation

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Description

Cluster 20. Group shelters type P.

NEW HOLLANDIC WATERLINE Introduction

GROUP SHELTERS TYPE P as components of a decentralised defence system added to the existing fortifications. The examples on and near the Fort at Tienhoven can be recognised fairly well in the field. Group shelters type P were built according to more or less uniform or standard design (especially) in the years 1939-1940 in multiple locations in the Netherlands. The total number of built examples is approximately 700, of which approximately 570 are in the New Hollandic Waterline; the majority (approximately 400) of these still exist. The building programme for group shelters Type P was not completed when the Second World War broke out and a number of examples are known never to have been completed. Type P (also called 'the pyramid' because of its distinctive form) is presumed to be the most well-known type of concrete defensive structure in the Netherlands. The type originated from the so-called VIS 77 (Regulation for the Construction of Positions no. 77), from 1928, and had among other purposes the function of forming part of the defence of a number of existing and new accesses, including especially (motorway) roads and (electrified or to be electrified) railways. The group shelter Type P was usually constructed in the immediate vicinity of already existing or simultaneously constructed casemates, gun positions, fortifications or trenches. Because the trenches and other earthworks were later almost everywhere levelled or demolished, the concrete shelters nowadays often lie partly below ground level. The traditionally completely closed front or facing side of the group shelters Type P was in many cases covered by earthworks that could form part of a glacis to protect the trench or a covered way. These earthworks are now mostly no longer present or only recognisable with difficulty, but particularly on forts or in otherwise broken terrain they are sometimes still present.

There are various variants of Type P, both in terms of dimensions and protection class as in execution and detailing. For instance, examples were built in protection classes W 15-21 and W 21-28 in sizes varying 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 examples of Type P were built in inundatable areas, in a number of cases with a visible pile foundation applied, while often a revetment wall and occasionally a trough with stairs to contain inundation water was inserted in the then elevated, square entrance and in others again a concrete foundation slab projecting all around is present.

Description

GROUP SHELTERS TYPE P, located at multiple locations on the Fort at Tienhoven and in its immediate vicinity. 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 at protection class W 12-15 or W 21-28. On the Eastern front most of them belong to the heaviest class. The group shelters Type P were built on a rectangular ground plan, with dimensions varying 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). The visible height above ground level varies, however. Both blind side walls and the rear side are executed vertically to approximately 3.00 m height. Above that these walls bend inward at approximately 45 degrees, then changing into a flat roof. On the right in the rear side is an access opening at locally varying height above ground level, usually square, but also rectangular. The entirely vertical, closed front side reflects the 45 degree angles and thus ends as a 'truncated pointed gable'. In a number of cases iron hooks or brackets were cast into the gable(s) which could serve to attach camouflage material. A characteristic component on top of the shelter type P is the conical concrete 'outlet', which was intended for the application of a periscope. These periscopes were rarely or never actually installed in practice. The interior of the group shelters Type P consists of a short corridor (usually with a concrete revetment wall or balustrade and normally several descending steps) and from there a 'lock' directed to the left which had to be closable by a (consisting of multiple parts) heavy, steel door with bolts. Via a second, similar door the space to the right could be reached, a rear-lying, almost square room, the actual shelter. The entrance could be swept from this room by a loophole for rifle fire. The steel doors are however rarely or never installed and the entrances were later often sealed with brick and plastered. 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 the firearm to sweep the entrance. The examples on and near the Fort at Tienhoven can be recognised fairly well in the field.

Valuation

GROUP SHELTERS TYPE P at and near the Fort at Tienhoven are of general interest because of:

* Cultural-historical values as part of the New Hollandic Waterline as designed by C.R.T. Kraijenhoff and constructed in first instance from 1815 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 arts, which is based on: a. the system of inundation and access defence (19th and 20th century), b. the race with increasingly powerful offensive weapons (20th century) c. the system of 'living' field fortification in depth (20th century)

These are components from the period 1939-1940, which are examples of reinforced concrete personnel shelters (Type P / Pyramid).

* Ensemble value and situational values as part of the New Hollandic Waterline. Also because of the functional and physical connection with the other components of the complex.

* The components are representative (characteristic) because they are clearly recognisable as part of a decentralised defence added to the existing fortification system.

* The components are reasonably well preserved and can still be easily recognised as built components in the field.