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Dimensioning of the Internal and External Carrying Capacity
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Internal Carrying Capacity |
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Internal Carrying Capacity
The material for the production of CTS/TITAN injection piles is approved micro alloy constructional steel StE 460 or StE 355 - depending on pile type - acc. to approval no. Z-30-89.1 of the Institute for Construction Technique, Berlin.
In the thread production process the material strength of the micro alloy steel is increased by cold forming without causing brittleness.
The advantage of this process is published in the technical data sheet.
The technical data are based on load test in the MPA NRW and the FMPA in Baden Wuertenberg. The cross section of the CTS/TITAN injection piles is determined by its weight. The yield and ultimate stresses are calculated from the tested yield and ultimate loads. Basically a safety factor of 1.75 to the yield is being applied acc. to German standards for safety/design loads, in the case mentioned on this page.
The internal carrying capacity is influenced by friction behaviour, crack width limitation and corrosion protection.
As with reinforcing bars, there has been a similar development for piles, from smooth to threaded tubes. The reinforcement type thread of the CTS/TITAN injection piles conforms to DIN 488, ASTM-A-615 and other international standards and can be calculated by the geometry of the ribs.
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The related rib area for the CTS/TITAN injection piles with 0.13 is very close to the maximum values for reinforcement bars. Consequently there is an optimum bond achieved like in reinforced concrete.
As with reinforced concrete these ribs include an equal crack distribution in the grout. Measuring these cracks widths at the geotechnical department of the University of Munich on excavated pile grout bodies reinforced with CTS/TITAN injection piles 30/11 have shown that up to 1.25 of the design load characteristic crack widths are below the permissible value of 0.1 mm as required for reinforcement to DIN 1045 16.8.5, Eurocode EC 2, ASTM-A-615, as well as BS 8081 1989 8.1.2.2.
This proves that the system complies with DIN 4128 9.2 and that single corrosion protection of minimum 20 mm cover, as with reinforced concrete, is sufficient. The internal carrying capacity derived from the yield load can be fully utilized for permanent tension piles. The internal carrying capacity for example can be determined by the yield load of 525 kN divided by the safety factor of 1.75 producing a safe or design load of 300 kN for the CTS/TITAN 40/16 (acc. to DIN standards).
---> External Carrying
Capacity
---> Calculation Example
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©Con-Tech Systems 31-May-2005 |
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