Calculation module A 161 / GW 312 for jacking pipes
The calculation module A 161 is used for the static calculation of jacking pipes and is based on the 2nd edition of the worksheet DWA-A 161 / DVGW worksheet GW 312, March 2014 edition. This worksheet is the first set of rules for the static calculation of pipes with partial safety factors according to Eurocode (semi-probabilistic concept).
The contents of worksheet DWA-A 161 and DVGW worksheet GW 312 are the same.
With our software for pipe statics IngSoft EasyPipe we offer a powerful program for the design of jacking pipes.
Scope
With this software you can examine all jacking methods (shield jacking, flush drilling, HDD *), burst lining etc.) of the rules and regulations on straight and curved routes or as curves.
*) Horizontal Directional Drilling, HDD: Horizontal directional drilling method → See below for details
Multi-stage pressure transfer rings (PTR) in preliminary design and CSV import of PTR tests are available. Drifting in loose rock and bedrock or mixed soils / transition area can be investigated. The calculation module iteratively determines the allowable tunneling force for the construction condition and performs the interaction check.
Verifications
All required verifications for the operating condition are performed automatically in parallel, if necessary, e.g.
- Fatigue check: check against not predominantly static load, dynamic check
- Road traffic load Load model 1, LM1: 2x10^6 load cycles
- Railroad traffic load Load model 71, LM71
- normal case: 1x10^8 load cycles
- steel pipes >1,5m covered: 5x10^6 load cycles
- Deformation proof
- Strain proof
- Stability check, buckling check
Load-independent boundary conditions such as minimum reinforcement, minimum internal forces and minimum wall thickness can be checked elegantly with IngSoft EasyPipe.
This allows you to design the press-through pipe or media pipe for the specified actions.
State of the art
Specifically, the program for pipe statics takes into account
- DWA-A 161 / DVGW GW 312 edition 2014
- Corrections to DWA-A 161 / DVGW GW 312 in May 2017
- Corrections to DWA-A 161 / DVGW GW 312 in October 2017
- Technical Note 4-2019 of DB Netz AG (Special regulations for steel press-through pipes for railroad crossings)
- Corrections to DWA-A 161 / DVGW GW 312 in September 2020 (material characteristics, via worksheet DWA-A 127-10)
- Corrected version March 2021
Our calculation module A161 covers regulations that are outside the worksheet DWA-A 161 / DVGW GW 312 or supplement it:
- TM 4-2019-10xxx I.NPF 2 to Ril 836.4501 and Ril 877.2203-Fatigue of steel pipes in the pressure range of railroad traffic loads: TM 4-2019 of DB Netz AG with steel pipes in notch case 71, KF 71 in the fatigue check.
- Technical guidelines of the DCA (Drilling Contractors Association, Verband Gueteschutz Horizontalbohrungen e.V.)
- DIN EN 1992: Eurocode 2 - Design of reinforced and prestressed concrete structures
- Pipe-specific and material-dependent codes wien DIN V 1201 and DIN EN 1916
Horizontal Directional Drilling (HDD)
Basically, the DWA-A 161 worksheet distinguishes between the following in the longitudinal direction during installation
- Pulled pipes, for example using the HDD method, as well as
- Pressed pipes (almost all other methods)
For HDD, the consideration of the Pressure Transfer Ring (PTR) and the verification of axial buckling in the construction state are omitted. The permissible force in the longitudinal direction is a tensile force. The program therefore determines the permissible force taking into account the permissible (axial) tensile strength. For some materials, this value is lower than the compressive strength. For examples, see DWA-A 161 Appendix E or DVGW-GW 321 Table 1f.
For longitudinal dimensioning during the pull-in, the calculation module uses the DCA guidelines (Technical Guidelines of the DCA (Drilling Contractors Association): Information and Recommendations for the Planning, Construction and Documentation of HDD Projects, 4th edition 2015. Verband Güteschutz Horizontalbohren e.V. (DCA), Aachen - DCA Technical Guidelines). The required and maximum tensile force determined in this way is superimposed on the smallest axial curvature of the pipe string at the most unfavourable point. The combined stress from longitudinal bending and longitudinal tension during construction is verified in the longitudinal direction.
During operation, all verifications required by A161 / GW312 are performed, including stability failure (buckling verification) and, if applicable, internal pressure, for time-dependent materials based on long-term material properties.