VOID Forming Spiral Tubes

Product Information

GP SPIRA-VOID tubing has, on account of its special corrugations, a very high radial stiffness well adapted for use as void formers in concrete structures. It is also being used as culverts and forms for concrete piles, plinths and columns. As void formers SPIRA-VOID tubes are used to reduce the cross section area and thus the weight of the structure. The weight reduction will amount to approximately 40% and thus produce a favorable effect on foundation, wall and slab construction.


On many construction projects like apartment buildings, parking garages, office buildings, industrial buildings, bridges, and docks, schools and hospitals, the introduction of SPIRA-VOID tubes will make it possible to use very long spans. The reduction in weight allows large areas and fewer columns which in turn will give technical economical and esthetic advantages.


GP SPIRA-VOID tubes meet with structural design specifications for void former. It is a very rigid but yet light weight sheet metal tubing that without excessive deformation, withstands existing forces during the pouring of the concrete. The Spiro seam is tight and no water from the concrete will enter the tubing. The low weight of the tubing makes it easy to handle.

Technical Data


SPIRA-VOID tubes are manufactured exactly to specifications.

Length is limited only by transportation. Standard diameter and thickness are shown in Table below. Other dimensions are available on request.

Cat No. NominalOutside
Diameter MM
Thickness Weight
150 154 0.5 2.06
200 201 0.5 3.34
250 252 0.5 4.17
300 302 0.5 5.01
350 351 0.5 5.85
400 402 0.5 6.71
450 453 0.5 7.55
500 504 0.5 8.40
600 605 0.5 10.00
700 706 0.7 16.47
800 807 0.7 18.82
900 909 0.7 20.80
1000 1010 0.7 23.12
1200 1213 0.7 27.80
1500 1521 0.7 34.45


Two different tubes corrugations are manufactured.

Type 6-8/3C with three 6-8mm deep corrugations between seams.

Type 15-20/IC with one I5-20mm deep corrugation between seams.


GP SPIRA-VOID tubes are made of cold rolled steel and hot dipped Galvanized Steel.

End Cones And End Caps

To close the ends of the GP SPIRA-VOID tubing, end caps or end cones can be used. Dimensions and total lengths are shown in the sketch below.

Jointing System

GP SPIRA-VOID tubes joined together by slip joint coupling

Note : Mobile Machine is available where the quantities and location warrants