3 m thick bunkers

[der bunkermann]

Yes, but maybe that is because the L409a are built on a high first dunerow vulneralble for low incoming enemy aircraft? (Edit: and navalartillerie)

[der bunkermann]

Above text make no sense, the L485 lies also high on the dunes.. i mistaked the location for that of the L487

[dirk Peeters]

The l 487 is standard 2 meter also
Dirk

[pierrot]

Hello Dirk

In Belgium we find both options: some bunkers with 3 sides 50% verstarkt and some with 4 sides.

The bunkers inside the divisional HQ of Dixmude (Diksmuiden) are 3m thick all sides (2x 117a, 1x 618, 1x 502, 1x halb 134 Sanität). Only the 622 is in Baustarkte B (2m). Note that the VF2a still existing there is also 50% verstarkt (wall of 1.50m).

Some other bunkers are also built with 3m wall like the 2x 669 from Stp Kolberg (Steene).
The R633 from PzStp Hafen (Ostend) has 2 or 3 walls 50% verstarkt I think.
The 502 that was used as HQ command post for the Flak battery of Mariakerke (Stp Boëlcke) has 3 sides 50% verstarkt, the entrance side stayed 2m

The bunkers built alongside the mole of Zeebrugge have all their wall against the mole itself 50% thinner than the other walls: the marine Luftschütz with walls of 1.1m have the wall against the mole only 0.55m thick and the 2 Luftwaffe bunkers from Stp Mölders built there (1x L402 and 1x L413) are built with walls of 3 m except the wall against the mole that is only 2m. In this case the 2m wall is one of the side of the bunkers, not the entrance side.


Gr.

Pierrot

[dirk Peeters]

thanks Pierrot
nice info

[pierrot]

Hey Dirk

Here the plans of the 502 from Stp Boëlcke and L413 from Stp Mölders.

L413 Stp Mölders.JPG (117.74 KiB) Viewed 1917 times

Gr.

Pierrot

[dirk Peeters]

thanks

[AvB]

Here's the document. (T-78 Roll 773).

[BunkerOwner2]

Hi Dirk, according to the germans bunkers that could not be completely be built underground, and thus be vulnerable for horizontal fire should recieve 50% thicker walls on the side that were most likely to be attacked.
Most bunkers have the entrance on the safe side so ticker walls were not neccesery.

In Scheveningen we have al ot bunkers with ticker walls due to the high groundwaterlevel.
Our 608 and 622's at the verteidigungsstab have 3 meter walls on all sites.
Dont ask me for the document right now.. but i have it from german doc
Gr, Tim

C'mon Tim?

None of the bunkers with 3m thick walls were build because of 'high groundwater level'....
Concrete vs water doesn't make any difference between 2 - 2,5 or 3m think walls...
Otherwise all the thinner bunkers and FA-works would be floated all the time?

Apart from the fact that most bunkers (if not all) in Scheveningen-Clingendael are all above sea level, and surely above groundwater level.
All earth-covered bunkers were 'sealed' with melted tar. And that was not to keep water out, but to prevent water in little cracks getting frozen and with that 'crack' the concrete. Just like trees do.

It was just that 'generation' of new bunkers and the demands they had when it came to protection-level against explosives...

[der bunkermann]

Hi Guido, you obviously you interpret my post wrong:

In places were the groundwaterlevel was to high, the bunkers could not be built completely underground.
Meaning the walls were vulneralble four horizontal fire and nearby bomb hits. in that case they could decide to built the wall(s) 50% thicker. This is made up by the festungpioniere, not by me.
Back/sidewalls that were in a dune or completely covered for another reason did not receive 3 meter walls.. this has tot nothing to do with "newer generations
of bunkers."
"Land above sea" level has nothing to do with the groundwaterdlevel at the landfront.
At some places in Scheveningen/ Den Haag groundwater level is very high. In the bundesarchiv there are wehrgeologen rapports that support this thought.
For instance: at WN 318 the groundwaterlevel is around 5.18 meter below the surface. If they want to built a ST bunker completely underground they had a serious problem:
At least 0.5 meter stampfbeton (sohle), 230 meters inside hight, 2 meters of roof and at least 50 cm ground above it. That means wet feet and a floating concrete boat..

The feldmaßige bunker were also built for a part above ground and later covered, these had 50cm roof and ditto floors so no problems with groundwater.

In the same period the landfront bunkers were built with 3 meter walls there was alot of bunker building going on at the seafront, with normal wall thickness.

Tar was very common, and used allmost on every bunker i've seen for the reason you mentioned above: waterproofing.

If you seriously want to investigate german bunkers you should stick to the facts and don't make assumptions.
Greetings, Tim

Edit: i misread your post about tar:
Do you know that the frostline in Holland is around 600 mm below the surface? That means even in the most extreme case the Frost never penetrates deeper than 600 mm, and the earthlayer above the roof is also minimal 500. Therefore i doubt frostprevention is the main reason for tar on the bunkerroof. But a german doc about that can change my mind very fast

[dirk Peeters]

At pointe du hoc de germans made this to reinforce the bunkers already build
they made extra walls at the enemy side

even the 636 was reinforced there this way

[der bunkermann]

Cool Dirk,
Were the bunkers built in formsteine or normally poured?

[dirk Peeters]

Good question
Look it up monday . Sorry
Family time now

[AvB]

All earth-covered bunkers were 'sealed' with melted tar. And that was not to keep water out, but to prevent water in little cracks getting frozen and with that 'crack' the concrete. Just like trees do.

Concrete absorbs water. The idea was to make it as dense as possible to keep the water out. Otherwise it would get moisty inside the bunker. Never read about water freezing underground in regards to bunkers.
Here's the official German document for your archive:

It was just that 'generation' of new bunkers and the demands they had when it came to protection-level against explosives.

Document I placed earlier in this thread posting.php?mode=quote&f=70&p=2172066#pr2142885 is from 1940. So no new generation of bunkers but already 100- and 500-series.

[dirk Peeters]

Cool Dirk,
Were the bunkers built in formsteine or normally poured?

normally poured