1. SELECTION CRITERIA FOR PIPELINE CONSTRUCTION
Mohamed Darwish, PhD, PEng
Aly Attia, BSc. 
Mohamed Yossef, BSc. 
Kirilos Yossif, BSc.
Ihab Khalil, BSc.
Presented by:
Mohamed Darwish, PhD, PEng

2. Introduction Pipeline Materials Iron (Cast Iron) Plastic (UPVC)
Steel (Stainless Steel)
FRP
Concrete
Aluminum
Ceramic
UPVC
Stainless steel
FRP
Ceramic
Concrete
Aluminum

3. Pre-Construction Phase Post Construction Phase
Construction Stages
Three Phases:
Pre-Construction Phase
Construction Surveying.
Grading, Cleaning and preparing the Right-of-way.
Topsoil Stripping.
Stringing.
Bending and welding
Construction Phase
Trench Method:
Open Trench
Plough technique
Trenchless methods:
Pipe Jacking methods
Utility tunneling
Horizontal Earth Boring methods
Pipe Ramming (PR)
Horizontal Directional Drilling (HDD)
Post Construction Phase
As Built Surveying
Hydrostatic test
Cleanup and restoration

4. Trench Method Open Trench
In the open trench method the crews begin to:
1- Excavate the trench
2- Positioning the pipeline
3- Install the valves
4- Finally backfill the trench.
If the pipeline is planned to be underneath a street or crossing water ways or if it is deep to the extent that trench side protection is expensive it will not be economical to use the trenched method.

5. Conventional Pipe Jacking (CPJ)
Trenchless Methods
Pipe jacking Methods
Conventional Pipe Jacking (CPJ)
Micro-tunneling
Method steps :
Drill the shaft (jacking pit) to place the jacking machine and another one at the end to be the reception shaft.
If a tunneling machine is used, it is connected to the control and the slurry container through the slurry discharging unit and the segment pipe is being fixed to the tunneling machine to start the installation process.
The first pipe is installed and jacked creating a tunnel then the other pipe is installed.
Then welding or connecting (depending on the pipe type) the first pipe with the second pipe takes place and the process continues and the pipes being jacked one by one after each other and welded/connected.

6. Trenchless Methods: Utility Tunneling
Similar to pipe jacking however, a liner (a support structure) is constructed as the tunnel excavation advances.
The liner is made of steel, concrete or wood.
After completing the utility tunnel, the pipe sections are inserted inside in their positions.
The space between the liner and the pipe is usually grouted.
This method is a two-phase operation as the phases of liner and pipe installations are separate while pipe jacking is considered as a one-step operation.
The pipes are designed and manufactured to take only permanent loads which saves a lot of pipe thickness reflecting lower costs.

7. Trenchless Methods: Horizontal Earth Boring Methods
As all trenchless methods, entry and exit pits are excavated first then the equipment are installed.
Within this family of methods, workers may work in the shaft or pit, but they do not enter inside the installed pipe. Therefore, these methods can be used for small diameter pipes.
This technology envelopes several methods including:
Horizontal auger boring (HAB)
Pipe ramming (PR)
horizontal directional drilling (HDD)
Pilot-tube micro-tunneling (PTMT).

8. Horizontal Earth Boring Methods
Horizontal auger boring (HAB)
Pipe ramming (PR)
A steel casing is jacked from a drive pit while the spoil is being removed through the steel pipe using a rotating continuous flight auger.
After fully installing the casing, the product pipe is installed using spacers and the annular space is grouted.
Due to the limitation of the auger size, the maximum recorded casing diameter was 1.5 m with a length of 240 m.
Sequential segments of steel casings are hammered using a pneumatic hammer then the pipeline is sequentially installed in the casing.
Due to limited hammering capacity, the maximum length of the rammed pipe line is 150 m.
Rock boulders could stop the process.

9. Horizontal Earth Boring Methods
Pilot-Tube Micro-Tunneling (PTMT)
Horizontal Directional Drilling (HDD)
A remotely guided machine drills from the access point till the reception point then pulls the pipe case through fixing a back reamer to it to the access point again.
Mini-HDD rigs can handle pipes with diameters up to 30 mm and are used primarily for urban utility construction.
Maxi-HDD rigs are capable of handling pipes as large as 1.2 m diameter having larger pullback forces.
Drive lengths that could reach 1800 m
The installation process is similar to that of HDD through the use of pilot boring followed by reaming and product pipe installation..
Utilizes a slant faced steering head for directional control similar to that used in HDD.
Adopts its accurate guidance system from micro-tunneling.
Similar to auger boring as both methods use jacking systems and auger flights for spoils removal.

10. Selection Criteria

11. Case Study 1: PEPSI Bottling Plant, Newport News, VA, USA
The purpose of this project was to install a new reverse osmosis water filtration system involving a 203 mm diameter drain pipeline instead of the existing 152 mm diameter pipeline .
The waste water in the facility has changeable pH levels that could cause rapid pipe deterioration requiring the use of a chemically sound pipeline.
1 m sections of 203 mm Vitrified Clay Pipe (VCP) was used in this job because of its highly resistive chemical properties.
The PTMT technique was used.
The entire job took two weeks to excavate and shore the pits, launch the pipe and restore the warehouse floor. The guided boring machine pilot tubing process and the pipeline installation was done in three days.

12. Case Study 1: Construction Procedure
The entry and exit pits were constructed.
The pilot tubes (with a diameter of 108 mm and a segment length of 750 mm) were installed on line and grade.
The dual-walled pilot tube utilized an illuminated LED target directed by the guidance system and prepared the route for the larger diameter casing.
After installing all of the pilot tubes, the 279 mm casings and augers were driven along the same route that was previously taken by the pilot tubes.
With the addition of each section of casings and augers in the entry pit, a section of pilot tube is removed in the exit pit.
Finally, each section of the VCP advances a section of casings and augers into the exit pit until the process is complete.

13. Case Study 1: Method Evaluation
Using a trenched method in an industrial facility like the one in this case would have caused this facility to be totally closed for several days which consequently would have caused significant financial losses to the owner. Hence, using a trenchless method was the right choice in such a case.
According to the selection criteria only pipe ramming, HDD and PTMT could be used to construct a 203 mm diameter pipeline .
HDD could not be used as the VCP is not flexible enough while the HDD could only be used when installing flexible pipes.
Pipe ramming could not be used as it involves hammering activities that could harm the substructure of the facility itself in addition to needing entry and exit pits that are larger in size due to using larger equipment.
Hence, the only choice left was the PTMT technique that was used in this project.

14. Case Study 2: The Santa Ana River Interceptor Relocation, Yorba Linda, CA, USA
This project (also known as SARI project), involved relocating 1433 m of sewer pipes in five segments including two siphon crossings and two curved segments.
One of the main challenges within the project was the ground conditions that included a mixture of cobbles and boulders within a weak sandy soil in addition to the presence of groundwater at a level significantly above the pipeline elevation.
Another challenge was the S-shaped curvature (double curvature) of one of the segments in addition to the depth of the crossings that forced the excavation to be significantly deep.
The method chosen was micro-tunneling in which a casing of a 2578 mm diameter was installed in four of the segments while the fifth segment had a casing that was 1956 mm in diameter.
Due to the soil type slurry shield MTBM’s were used in the project.

15. Case Study 2: Construction Procedure
Entry and exit shafts for each of the five segments were excavated.
For the S-shaped segment an intermediate shaft was constructed at the inflection point of the S-curve in order to perform the job in two drives (each with a curve having a constant radius).
The MTBM’s were lowered into the drilled shafts at both ends then the MTBM boring started.
As the machine rotates, the spoil is taken through the slurry circulation, the slurry is refined in its bentonite slurry unit and returned again.
Meanwhile, the casings were jacked using hydraulic jacks.
RC casings were used in 3 of the 5 segments while steel casings were used in the other 2.
The installed sections were then connected to the previously installed ones to form the micro-tunnel lining.
Finally, the PVC sewer pipes were installed and grout was injected between the casings and the pipes.

16. Case Study 2: Method Evaluation
The fact that the pipeline was crossing two siphons and was 19 to 20 m deep made it impossible to construct any of its segments using the trenched method.
According to the selection criteria, CPJ, MTBM’s, UT and PR are the only methods that could construct a pipeline with the diameters specified for this project.
Of these four methods only the micro-tunneling method was capable of constructing single drives within the order of 300 m that is needed in each of the project drives.
On the other hand, choosing a slurry shield MTBM was dictated by the soil conditions due to the presence of high ground water pressure and due to the soil type as using an unshielded open face MTBM would have been catastrophic and using an EPB shielded MTBM would have been inefficient due to the cohessionless nature of the soil.

17. Conclusion
The most governing factors of choice are the pipe diameter, length, the soil conditions and material.
When examining the methods applied in the two cases discussed in this paper against the developed selection criteria, the selection criteria proved that it covered the different aspects governing the selection of the most suitable methods for different pipeline construction cases.
It is highly recommended when using the selection criteria matrix to take all the factors governing the method selection into account as neglecting some of them could cause real problems.

18. Acknowledgements
Department of Construction Engineering in the American University in Cairo.

19. References
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20. Thank you