Joints for Diaphragm Walls prepared by Erwin Stötzer Nov. 2000

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 - 7.0 m Successive panel 1.0 m - 2.8 m 2.8 m Guide for the grab 2. bite 1. bite 0.5 m - 2.8 m 2.8 m Closing panel 2. bite 1. bite

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

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

Standard Joints constructed with Stopend Pipes lifting head bolted coupling

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 )

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

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

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

Joints constructed with Prefabricated Concrete Elements

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

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

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

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

Joints constructed with Endplate Reinforcement Cage

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

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

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

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

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

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

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

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

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

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