1. Joints for Diaphragm Walls
prepared by
Erwin Stötzer
Nov. 2000

2. Standard Joints constructed with Stopend Pipes
Excavation with
Grab length 2.8 m
Reinforcement and Concrete
Primary panel
2.8 m
1. bite
2. bite
2. bite
2.8 m
2.8 m
2.8 m
6.4 m m
Successive panel
1.0 m m
2.8 m
Guide for the grab
2. bite
1. bite
0.5 m m
2.8 m
Closing panel
2. bite
1. bite

3. Standard Joints constructed with Stopend Pipes
stopend pipe extractor
stopend pipes with coupling

4. Standard Joints constructed with Stopend Pipes
stopend pipe extractor
concreting primary panel with two stopend pipes

5. Standard Joints constructed with Stopend Pipes
lifting head
bolted coupling

6. Standard Joints constructed with Stopend Pipes
Method of Construction:
Features
excavation of the trench with the
grab or cutter
installation of the stopend pipe at
the end of the trench
installation of reinforcement cage
pouring concrete into the trench by
the tremie method. A sample from
every concrete batch will be taken
to monitor the curing process of the
concrete in the trench.
when the concrete starts hardening
pulling out the pipe by hydraulic
operated casing extractor.Adjust the
speed of extraction to the hardening
time of the concrete.
system is used for a trench depth down
to 25 meters
guide wall has to be designed for the
forces from the casing extractor
a job site with one grab unit two sets of
Stopend pipes and two casing extractors
and for two grab units three sets of pipes
and two extractors are required.
the watertightness of the joint is sufficient
for a water pressure of 4 to 6 m.
this system requires experienced staff on
on site
after finishing the concrete operation the
extraction procedure requires at least 6
hours more ( usually night work )

7. Joints constructed with Prefabricated Concrete Elements
waterstop
gravel
fill
to avoid
concrete
flow
primary panel
secondary panel

8. Joints constructed with Prefabricated Concrete Elements
precast element
waterstop
core through precast element and
cast in situ concrete panel
installation of the precast element

9. Joints constructed with Prefabricated Concrete Elements
with waterstop
exposed diaphragm wall with precast element

10. Joints constructed with Prefabricated Concrete Elements

11. Joints constructed with Prefabricated Concrete Elements
Method of Construction:
Features
excavation of the trench with the
grab or cutter
installation of the prefabricated concrete
elements at the end of the primary
trench
installation of reinforcement cage
pouring concrete into the trench by
the tremie method. To avoid concrete
flow behind the PC-element gravel dia
30 to 50 mm will be installed between
the end of the trench and the PC-
element
construction of secondary element under
the guidance of the PC - element of the
primary panel
system is used for a trench depth down
to 25 meters or the lifting weight of of the
PC - element of 25 tons
for greater depth the PC- element can be
installed in several pieces and connected
together during installation procedure
the PC - element guides the grab during the
excavation of the secondary element
the watertightness of the joint can be
improved by placing waterbars in the PC-
element

12. primary panel Joints constructed with Endplate Reinforcement Cage
excavation
concreting
300 mm
2200 mm
300 mm
waterstops fixed to the steel plate
grab width 2800 mm
Geotextile sheet fixed at the steel plate to prevent
concrete flow behind the
plate, overlapping 0.5 m
H - beams to keep
cage in position
during concreting,
be extracted during concreting

13. length of secondary panel
Joints constructed with Endplate Reinforcement Cage
excavation of secondary panel
excavated primary panel
concreted primary panel
H - beam
6.5 m to 7.5 m
length of secondary panel
Gravel
geotextile sheet
covers the
reinforcement cage
steelplate embedded 50 cm into soil

14. Joints constructed with Endplate Reinforcement Cage
lifting head sheeted reinforcement cage
filling with gravel behind endplate before concreting

15. Joints constructed with Endplate Reinforcement Cage

16. Joints constructed with Endplate Reinforcement Cage
Method of Construction:
Features
excavation of the trench with the
grab or cutter
installation of the of the H - beams on
both sides of the trench
installation of reinforcement cage equip-
ped with endplate and geotextile sheet
fill gravel 30 to 50 mm between steel
plate end of the trench
pouring concrete into the trench by
the tremie method. During concreting the
gravel and the H - beam will hold the
cage in postion.
construction of secondary element under
the guidance of the of the steelplate of
the primary panel
system is used for a trench depth down
to 80 meters
the endplates guides the grab during the
excavation of the secondary element
the watertightness of the joint can be
improved by placing waterbars at the end-
plate

17. Joints constructed with the CWS ( contignous waterstop)
primary panel
CWS steelform
waterstop
primary panel
secondary panel

18. Joints constructed with the CWS ( contignous waterstop)
exposed joint with two waterstops
system with one or two waterstop

19. Joints constructed with the CWS ( contignous waterstop)
steelforms for CWS system: single waterstop
double waterstop

20. Joints constructed with the CWS ( contignous waterstop)
exposed CWS joint

21. Joints constructed with the CWS ( contignous waterstop)
Method of Construction:
Features
excavation of the trench with the
grab or cutter
installation of the of the CWS steel form
with the waterstops on both sides of the
trench
installation of reinforcement cage
pouring concrete into the trench by
the tremie method.
construction of secondary element under
the guidance of the of the CWS form
located in primary panel
during excavation remove the CWS form
by vibrator or hooks at the grab (Patent
by Bachy )
system is used for a trench depth down
to 20 meters
the watertightness of the joint is improved
by the waterstops of the CWS system
in every primary panel two CWS forms
should be placed, they only can be removed
during excavation of the secondary panel

22. Joints constructed by overcutting the Primary Panels
H - beam
primary panel
cutter

23. Joints constructed by overcutting the Primary Panels
cutter
secondary panel
primary panel
primary panel
H - beam to be removed
during concreting

24. Joints constructed by overcutting the Primary Panel
cutter wheel with teeth
shape of the cuttingjoint

25. Joints constructed by overcutting the Primary Panel
Method of Construction:
Features
excavation of the trench with the
cutter
installation of the of the H - beam to keep
the reinforcement during concreting in
position
installation of reinforcement cage
pouring concrete into the trench by
the tremie method, pull the H - beam out
of the soft concrete
system is used for a trench depth down
to 120 meters
the watertightness of the joint is improved
when cleaning the overcutted joint before
installation of the reinforcement cage by
brush