In-the-wall Joint Jacking Pipes

Concrete pipe jacking is a method of installing pipelines without disrupting existing surface facilities or activities. With the increasing growth in South African cities and towns and the consequent need to refurbish, renew and upgrade existing services, pipe jacking is seen to be a growing industry. Although the basic methods of concrete pipe jacking are similar for all pipeline applications, South African contractors have developed their own individual tech-niques to achieve accuracy during jacking, to lengthen the jacking distance and to control varying ground conditions.

Installation method

Concrete pipes are jacked from a jacking pit to a receiver pit usually located at a manhole or access chamber. The main jacks are installed in the jacking pit and are used to push the concrete pipes into the cavity excavated ahead of the progressing pipeline. The main jack capacity depends on the size of pipe, length of the line and the type of ground in which it is being jacked. There are typically two or four jacks with capacity of up to 300 tonnes.

The jacking forces are resisted by the thrust block in the jacking pit and applied to the pipeline end through the steel thrust ring. The concrete pipe end is protected against spalling by soft wood or woodchip joint packers between the thrust ring and the concrete surface. The steel cutting shield fitted to the lead pipe gives protection to workers and allows steering and alignment adjustments. Intermediate jacking stations may be required in long lengths and hard ground conditions. Alternatively bentonite injections may be used to reduce the friction between the pipes and the soil.

Pipeline alignment is continually monitored and adjusted during jacking by laser from the jacking pit to a target fixed to the inside crown of the lead pipe or shield. Gradual adjustments are continuously made to avoid over-stressing the concrete pipe joints.

Jacking Class 100D - SABS 677 Type SC
Nominal
Diameter
Inside
diameter
Outside
diameter
Wall
thickness
Standard
lead
Length Mass
(mm) (ID mm) (OD mm) (T mm) (mm x mm) (mm) (Kg/unit)
840 Butt 810 1034 112 50 x 10 2260 1878
900 880 1100 110 200 x 20 2500 2190
1050 1030 1250 110 200 x 20 2500 2523
1117 1117 1375 129 424 x 20 2260 2922
1200 1150 1390 120 200 x 20 2500 3065
1350 1350 1600 125 200 x 20 2500 3708
1473 1473 1780 154 560 x 20 2260 4540
1500 1460 1720 130 200 x 20 2500 4158
1800 1760 2120 180 200 x 20 2500 or 2300 7025
1880 1880 2236 178 756 x 20 200 5760
2000 Butt 2032 2432 200 80 x 12 2000 7000
2100 2100 2500 200 200 x 20 2000 7400
2350 2350 2950 300 200 x 20 2000 12795
2400 2400 2800 200 80 x 12 1000 4180
2500 2500 3000 250 200 x 20 1500 or 2440 13493

Nominal length 2,5m.

Pipes available in half lengths by arrangement.

Details of larger diameter pipes available on request.

SI on request.

Dimensions and thus the mass of the pipes are subject to change without notice.

For details of pipes from any particularfactory, please contact our sales office.

All dimensions in mm.

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In-the-wall Joint Jacking Pipes
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In-the-wall Joint Jacking Pipes