USAFE TAB-VEE shelters and their genesis


Hahn photo by ? (source lost)

I've always been intrigued by the idea of building a 1/72 scale version of a USAFE TAB-VEE shelter, like I had seen at bases like Spangdahlem, Ramstein, Hahn and others. In 2020 I started looking for open sources on the subject, and found many documents with detailed information. They also tell how the US aircraft shelter evolved, and I found it fascinating. Hence this report starts in the early 1960s. Since these shelters are now 50 years old, and open to the public in many cases (think of Bitburg, Soesterberg, Hahn), I don't think they still are military secrets.



Wonder Building Corporation

The 'Wonder Building Corporation of America' was located in Chicago (IL). The company is sometimes called 'Wonder Trussless Building Cooperation' but I think the 'trussless' part comes from a logo used in advertisements. Wonder Building Corp produced a line of steel arch elements that were used to build roof structures, usually called a 'Wonder arch' or a 'Wonder roof'. They were used to build small factory halls, warehouses, swimming pool halls, aircraft hangars, etc. The archived Wonder buildings - assembly and specification manual (PDF) from 1960 gives a great overview of the civilian applications of this type of structure. Unfortunately, the manual does not describe the arch elements themselves.

More specialized applications of 'Wonder arches' were found on the South Pole, see US Arctic Program Photo Library and Amundsen-Scott South Pole Station. Wonder Buildings also tapped into the private fallout shelter market. In 'Oppenheimer Is Watching Me: A Memoir', writer Jeff Porter states: "The Chicago Wonder Building Corporation was selling two hundred fallout shelters a week by 1961, at a thousand dollars a crack, and had become famous for their 'trussless' form (erect it yourself!)"

I think Wonder Building Corporation no longer exists, but I found a Spanish video of the Erection of a Wonder prefabricated steel building

Although the word is never used to describe the Wonder structures, they are true monocoques, because the 'skin' is the only structural member. I think the idea compares to the Nissen hut, although these had a wooden semi-circular frame (purlin) each 1.6 m, and are thus not true monocoque structures. Similarly, the 'Romney hut' and the 'Quonset hut' have frames / purlins too, and on the Quonson hut the corrugations are mostly horizontal, meaning it does not contribute to the strength and merely serves as covering.

One of modern equivalents of the Wonder Arch is the K-Span. The single-piece arches are made on site, starting with a roll of flat steel sheet. Here's a video of a K-Span in Afghanistan, and another in Czech Republic: Construction of production arched hall. Chinese versions can be seen too: K-Span forming machine and K-Span machine maxine [sic]. Another modern version of the Wonder Arch is Quick Span Arch Building Machine.



Aircraft shelters in Vietnam

Starting in 1968, some 500 aircraft shelters were built in South-Vietnam, to protect the aircraft against ground attacks. These shelters had been developed since 1962 under 'Project 1597' ('Protective Shelters for Tactical Aircraft') and 'Project Concrete Sky', and used the Wonder arch structure as a main component. A number of articles and books contain solid information about these Vietnam shelters. But first a quick view in three pictures how the Vietnam shelters were built.

First, the sheet metal arch elements are bolted together. The pictured elements were produced by US Steel (USS), whose logo is printed twice on each element. Element length varied per manufacturer, and these look rather short to me. The bolting, with 33 bolts per arc element connection, made construction a laborious process.

Source: Wonder Arch Aircraft Shelters photo series on Flickr by 'manhhai'
A set of three half-rings is built up and then erected. I roughly calculate a weight of 5500 lbs / 2500 kg. The set flexes a lot during the lifting.

Source: Wonder Arch Aircraft Shelters photo series on Flickr by 'manhhai'
With the wonder arch structure ready, concrete is poured in 4 feet heights, alternating left and right to avoid too large asymmetric loads on the arch. The top section is not poured inside a casing, but apparently shaped by hand. The rod ends that stick out are probably used to indicate the concrete layer thickness.

Source: Wonder Arch Aircraft Shelters photo series on Flickr by 'manhhai'

The book Southeast Asia: Building the Bases. The history of construction in Southeast Asia (PDF) reports on pages 388-390 that:



The Checo Report: The Air War In Vietnam 1968 - 1969 reports on page 73:



The four-page article Protective aircraft shelter (Air Force Civil Engineer, Volume 10) from May 1969 gives a nice overview of the shelters built in Vietnam. Here's a summary of the technical aspects:

As an addition to the article, I see two different types of concrete covering. Most shelters have a smooth exterior, others have a corrugated exterior. The reason for this difference is unclear.

'Aircraft Shelters in Vietnam' in The Military Engineer (PDF) gives another overview of the project, and adds that 'Each shelter is composed of 324 panels (with a total weight of 31 tons) bolted together into 36 rings with 15,141 bolts'.



From Aircraft Shelter Explosives Quantity-Distance Evaluation, Concrete Sky, Phase IXB (PDF) we learn some more details of the spacing between the Vietnam shelters:



The book Engineers at War reports that the US Air Force had planned 408 shelters in Vietnam, at six bases, but 392 were actually built: 98 at Da Nang, 75 at Bien-Hoa, 62 at Tan Son Nut, 40 at Phu Cat, 61 at Phang Rang and 56 at Tuy Hoa. The book reports on page 452:

Yet another source is the book Air Base Defense in the Republic of Vietnam.



Navy / Marines 'Wonder arches' in Vietnam, 1969 and on

According to the articles below, Seabees construction engineers built forty-five shelters at Da Nang in 1969, then twenty at Marble Mountain Air Facility (a.k.a. Da Nang East), and finally forty at Chu Lai. They were open at both ends. In Google Earth I count 106 (this includes USAF shelters), 21 and 33 respectively remaining at these airfields. Here are two accounts of the building process, with photos:

The shelter sizes are not mentioned, but they were most likely identical to the 48' USAF shelters. In Google Earth, I measure approximately 51.5' / 15.7 m exterior width, taking the shelters in the north-west corner of Da Nang for the measurements. As far as I could find out, the Air Force used the east side of the base, the Marines the west side.

Another source is: Building the Navy's Bases in Southeast Asia (PDF), pages 388-390.



The USAFE TAB-VEE shelter

TAB-VEE is short for 'Theater Air Base Vulnerability Evaluation Exercise'. Note that TAB-VEE is also written as 'TAB VEE', 'TAB/VEE', 'TAB-Vee' or 'TAB-V'. This program was started in 1968, following the Arab-Israeli war of 1967, and the Vietnam war experiences. Its aim was to provide better protection for USAFE airfields. It involved better protection for aircraft, runways, ammo storage and other aspects of air bases. Judging from reports online, the design was designed for a conventional bomb to explode near it, but not for a direct hit with one. A submunition or a rocket could be sustained. It could definitely not withstand a nuclear attack. Building for peace: United States Army Engineers in Europe, 1945-1991 (PDF) (page 160-161) reports that construction started in 1969, and by April 1972 324 TAB-VEE aircraft shelters had been constructed at Ramstein, Sembach, Bitburg, Spangdahlem, Hahn, Erding, and Zweibrücken (all in Germany), Soesterberg (Netherlands), Aviano (Italy) and Incirlik (Turkey). Air Force Engineering & Services Quartely, November 1977 article reports that the grand total of TAB-VEEs built at USAFE air bases was 396, but so far I've counted 335 (see census below). I also learned that not all shelters were used for aircraft, some were used for ground equipment or weapons. Note that the TAB-VEEs built in Korea had no doors.

As far as I understand, these first generation shelters were identical to 'Concrete Sky' shelters built in Vietnam, with the addition of a back wall and internal clamshell doors, which required an increased length, from 72' to 100'. The internal length was appr. 90', and the inside width was 48'. However, the clamshell doors reduced the last number to 42' or 43'. The shelter was suitable for all then-current TAC aircraft: F-4E (length 63'0", span 38'5"), F-111A (length 73'6", span swept 32'0") and A-7D (length 46'2", span 38'9"), plus any smaller aircraft of course. A small cutout in the inside of the shell had to be made to make room for the upper hinge of the clamshell doors. This was compensated with two concrete patches on the exterior (see opening photo).

During the construction process, it became clear that the F-15, that was under development (length 63'9", span 42'10"), would be an extremely tight fit in the clamshell door opening, leaving one inch on either side. I've read that floor rails were fitted to guide the aircraft, but I haven't seen photos that prove this. The height of the double fins (18'8") might also present a problem, but in a sketch I measure around 1' clearance. To solve the problem, a new door was designed, moving the clamshell doors to the front edge of the shelter, where they were welded together and made to slide sideways. This design was built at a few air bases: Bitburg, Incirlik and Soesterberg. These shelters are called '1st generation (modified)' shelters.

Although heavily redacted, Military Construction Appropriations for 1975 give an impression of the era of transition from the TAB-VEE to the next shelter designs.

I think that the F-111 actually required a shelter where it could be parked with the wings swept forward (span 63'). Therefore, the introduction of the F-111 in USAFE lead to the 2nd generation shelter, that was probably no longer called TAB-VEE, but Hardened Aircraft Shelter (HAS). Its 124' x 82' internal dimensions more than doubled the floor area. The shelter's cross section has a compound radius, by combining arch elements of two radii. The second generation retained the 18-inch concrete roof covering; therefore, the shelter still did not protect against direct bomb hits. The design was not intended to defeat precision attack, nor nuclear attack. The doors were 1' thick concrete, sliding sideways, with a steel spaceframe for stabilization. A strange aspect of the door is that they are smaller than the shelter; there is a partial front wall to fill in the remainder (see Quintin Lake photos). The original design (not built) had a different recessed door system, consisting of four hinged sections, operating like Dutch doors (as in German shelters). This type was only built at Upper Heyford, 31 pieces, around 1976-1977 I believe. See Air Force Engineering & Services Quartely, November 1977 article.

For reasons I haven't been able to reconstruct, the 2nd generation shelter was very quickly replaced by the somewhat smaller 3rd generation shelter. It shares nearly all design details with the 2nd generation shelter, but internal dimensions are 120' x 71' instead of 124' x 82' (i.e. 84% floor area). For this type we know how the compound radius was made: the middle has a radius of approximately 45' radius over a 66 degrees arc, that connects to 24' radius arcs on either side, that connect vertically to the floor. The third generation shelter was also easily big enough for the next type to be added to the USAFE inventory, the A-10 (length 53'4", span 57'6"). All USAFE shelters constructed after the 2nd generation shelter were of this type. For the fiscal years 1976 to 1978 350 shelters were to be built according to Air Force Engineering & Services Quartely, November 1977 article; I counted 31 + 367 = 398, but this includes shelters for the A-10 Forward Operation Location program that did not yet exist in 1977. Protection levels were the same as before, see High Explosive Testing Of Hardened Aircraft Shelters (PDF), with an interesting observation that the inside steel exhaust doors went flying in one test. DoD 'Approved Protective Construction (Version 2.0)' (PDF) also discusses the same shelter tests.


From: Tech Order 00-25-172 'Ground Servicing Of Aircraft And Static Grounding / Bonding' (PDF)



     Internal dimensions     


     External dimensions @    


Features

1st generation (unmodified) length 100' / 30.5m *
width 48' / 14.6m
door width 42' or 43'
length
width ~53.4' / ~16.3m
* internal length with doors closed appr. 90'
Clamshell doors inside the shelter
Personnel entrance through door in left-side clamshell door
Patch on the exterior
I think different types of exhaust deflectors were used, maybe even on one air base
1st generation (modified) length ~100' / ~30.5m
width 48' / 14.6m
length
width ~53.4' / ~16.3m
Single sliding door, made from repurposed clamshell doors
Personnel entrance through sliding front door, left side
Usually no patch on the exterior
I think different types of exhaust deflectors were used, maybe even on one air base.
2nd generation length 124' / 37.8m
width 82' / 25.0m
length
width ~88' / 27m
Personnel door on the right side
Inverted J type ventilation tubes on top of shelter, usually alternating left and right
Concrete apron for ground equipment on the right side, with possibly a lead-through in the shelter wall
Partial front wall, since the doors are smaller than the shelter
3rd generation length 120' / 36.6m
width 71' / 21.6m
length
width ~77' / ~23.5 m
Personnel door on the right side
Inverted J type ventilation tubes on top of shelter, usually alternating left and right
Upward-pointing 'wings' on the exhaust deflector
Concrete apron for ground equipment on the right side, with possibly a lead-through in the shelter wall
However, ground equipment is often seen inside the shelter too

@ external dimensions are of the arch only, without foundation, door support, annex building and / or exhaust


I found some photo reports showing USAFE TAB-VEE shelters:

Google Earth also has lots of excellent photos of shelters made on air bases that are no longer in military use.



Zweibrücken TAB-VEE drawings

Larry Engesath very kindly sent scans of basic construction drawings, that he saved from his years at Zweibrücken as a camera technician. They clearly show the original 1st generation type, unmodified, with the doors inside the semicircular shelter. Measurements are in SI units.







CAF Lahr 3rd generation shelter drawings

Many years ago, I found a brochure for a 'shelter for rent' at Lahr, formerly used by the Canadian Air Force. As far as I can see, this shelter design is identical the the USAFE 3rd generation shelter. The 3rd generation shelter is often called a NATO standard in official documents, so it's not strange that they are identical.







Soesterberg TAB-VEE shelter construction, 1969

The Royal Netherlands Air Force took fantastic aerial photos during the construction of first generation (modified) TAB-VEE shelters at Soesterberg in 1969. I found the photos on the website of the Nederlands Instituut voor Militaire Historie, and put them in an order that shows the construction process from start to finish.

  Start of construction of the foundation. Lots of rebar. Photo courtesy of NIMH.
Concrete edge foundation is cast. The shelter floor has not been laid yet. The function of the black beam across the shelter is unclear. Photo courtesy of NIMH.  
  Casting of the rear wall in progress, using what looks to me like a rather primitive casting mold of narrow wooden planks. Photo courtesy of NIMH.
Rear wall with a 'lip' to connect with the arches. The rear wall has unusual exhaust gas openings. I'm not 100% sure, but I think we're looking at the single shelter that was built with a 150' instead of 100' length. See three photos down for a better view. Generally you will see one of these in each TAB-VEE shelter area. Possibly these unique shelters were not meant for operational use? Photo courtesy of NIMH.  
  Some shelters were built with the shelter floor and ramp constructed first. The foundations for the two shelters themselves are also visible. Photo courtesy of NIMH.
A taxiway is used to assemble the arches. First, the arch elements are bolted together to a single span, then more elements are added until three rows of elements are bolted together.

Since the combined weight of a three-row arch is probably around 5500 lbs / 2500 kg, a crane is most likely used to move the arches to the shelter site. Photo courtesy of NIMH.
 
  The first three-ring arch is positioned against the back wall. Interestingly, this photo shows the extra long (~150' length) version. Photo courtesy of NIMH.
The complete arch roof has been built up here, against the concrete back wall, that still lacks the exhaust channel. It's not clear what the workmen are doing here, possibly tightening all the bolts? There is no rebar visible on the Wonder roof, but there is rebar for the future exhaust. Photo courtesy of NIMH.  
  Another photo of the same stage. The standard exhaust opening in the rear wall is clearly visible here. It's about the size of the VW bus. Photo courtesy of NIMH.
The outer casing for the concrete pouring is being assembled here. A crane is on its way with the one but last casing element. Each side gets six casings. The casing elements connect to the small dark rectangles on the foundation. On the top side, they connect to the opposing element with a framework. Note that the casings leave the very top of the shelter open; it seems that area is flat enough for concrete to be shaped by hand. Photo courtesy of NIMH.  
  The same situation from a different angle. There is no casing yet to close the semi-circular slot on the front side of the shelter. We can see that there is no concrete floor in this shelter yet. Photo courtesy of NIMH.
It looks like the concrete has been poured on this shelter. Again it seems to lack a concrete floor. Photo courtesy of NIMH.  
  In this photo the exhaust channel has been added, blowing upwards. You can also see multiple edges of the cancrete casting molds. Photo courtesy of NIMH.
In this photo, construction of the ramp that connects the shelter with the taxiway is underway. I think I see leveled and compacted sand with vertical wooden (?) planks, ready for pouring concrete. Again, no rebar is in sight.

On the shelter itself, the upper edges of the pouring casings can be seen, they leave two ridges on the top of the shelter. Photo courtesy of NIMH.
 
  The shelters were fitted with a single sliding door, that is being sandblasted or painted here. As far as I can tell, the strange shape of the door is explained by its former intended use as two swinging doors mounted inside the shelter. For the doors to opening inside a semi-circle, they required this unique shape. The two doors of the original design were simply welded together. A new semicircular part was added, probably steel sheet filled with concrete.

While closing, the door slides in a quarter-circle channel on the left side of the shelter. This probably also explains the small step in the circumference of the door. Interestingly, none of the photos show a guide rail on the ramp, possibly this was an afterthought?

Also, the concrete looks very weathered already. Just maybe the doors were fitted some time later? Two ramp lights have also been fitted to the shelter. Photo courtesy of NIMH.


USAFE shelter census

I used Google Earth to do a rough count of shelters on USAFE air bases. The stand-alone version of Google Earth includes historical imagery, that was often needed because of demolitions. If you have more accurate count(s), please let me know. Air bases indicated # are deployment air bases, only used in exercises. Air bases indicated % are A-10 Forward Operating Locations, used irregularly by 81TFW.


     1st generation     
unmodified
     1st generation     
modified
     2nd generation           3rd generation                Comments
Ahlhorn % 0 0 0 17
Alconbury 0 0 0 26 * * all thirteen on the south side were demolished to make room for Alconbury Weald with 5000 new homes. One random shelter on the north side was also demolished
Additionally 13 super-wide shelters for TR-1 / U-2R
Aviano 15 * 0 0 35 * including one 125' and one 150' versions
Bentwaters 0 0 0 21
Bitburg 0 66 * ** 0 0 * an accurate count is impossible since reconstruction is well underway in the oldest Google Earth photos (2009). For example, I see two empty spots that could have been shelters, but I can't be sure.
** at least two 125' and three 150' versions
Boscombe Down # 0 0 0 18
Erding # 18 * 0 0 0 * one 150' version.
This is probably the most undisturbed set of first generation shelters
Gilze-Rijen # 0 0 0 16 constructed in 1976 and 1977
Hahn 43
* **
*** ****
0 0 2 ***** * I count 18 in the south shelter area and 25 north shelter area
** one more in the north-west of the north shelter area, not connected to taxiway
*** one 150' version in each shelter area
**** five demolished in the south shelter area
***** one each in both shelter areas, but the one in the south area was demolished
Incirlik 0 28 * 0 21 * including two 150' versions and one 125' version
Jever # 0 0 0 23 constructed in 1976 and 1977
Lakenheath 0 0 0 60
Leipheim % 0 0 0 10
Norvenich % 0 0 0 10? 3 remaining
Ramstein 74 * ** 0 0 12 * * in the east shelter area, five 1st gen shelters closest to the taxiway-turned-runway, and a new apron, were demolished between 2000 and 2010, plus one 2nd gen between 2010-2015. In the west shelter area, the two 3rd gen shelters closest to the taxiway-turned-runway were demolished between 2000 and 2010. In the north-east shelter area, 11 first generation and 1 third generation shelters were demolished between roughly 2005-2015
** including two 150' versions and one 125' version
Sembach 0 0 0 13 * * one demolished in west area, looks like more will follow
Soesterberg 0 18 * 0 17 ** *** * 5 remain, rest demolished. One 125' and one 150' version. Area not open for public.
** area open for public, some shelters are open
*** constructed in 1977
Spangdahlem       48 * 0 0 24 * including two 150' versions
Upper Heyford 0 0 31 27 * * 9 north side, 18 south side
Woodbridge 0 0 0 17
Zweibrücken ~41 * 0 0 0 * 10 of ~23 remain in the north shelter area, all 18 in the south shelter area are demolished
Total 241 112 31 369 Grand total 753 so far. RAND Research Report 968 says: 'By the end of the Cold War, the United States had constructed roughly 1,000 such shelters in Europe and the Pacific'.


Other countries

The air forces of many other countries built the same type of 1st generation TAB-VEE shelters. So far I've identified Greece, Italy, Spain and Iran. As far as I can see, they all built the 1st generation TAB-VEE shelter. Maybe the size was slightly different, for example at Villafranca I measured ~18 m width, instead of ~16.3 m for the USAF TAB-VEE.

When measured in Google Earth, RAF (not RAFG) shelters have the same dimensions as the USAFE 3rd generation shelters, and a similar door design, but other annex buildings and probably a different exhaust. I do not know how much they have in common with the USAFE shelter - to be investigated.



Crew recollections

Some collected recollections:



Modeling details

Some remarks to help construction of a scale TAB-VEE:



Models

Barrie Raterink (NL) was probably the first to use the above information for a scale model. He made a 3D CAD model of the 3rd generation shelter in 1/144. He went to the former Soesterberg air base to take a better look at the door frames and the concrete ballast blocks. He plans to print the main parts on a filament printer, and the detailed parts on a resin printer.







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