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About additional investigation result concerning material test of polyethylene cylindrical tube used for prestressed concrete bridge

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April 4, 2008
East Nippon Expressway Co., Ltd.
Central Japan Expressway Co., Ltd.
West Japan Expressway Co., Ltd.

Regarding the marking, in the construction ordered by East Nippon Expressway Co., Ltd. /Central Japan Expressway Co., Ltd./West Japan Expressway Co., Ltd. (hereinafter referred to as NEXCO3 company), the PE sheath material test We would like to inform you that we have confirmed the following when conducting a survey on the companies listed in the test report of "Sheath JHS421" established in April 2004).

1 Status of manufacturing companies and sales companies surveyed

This survey revealed that the total number of affiliated companies related to JHS421 was 8 to 10, which was initially known. The breakdown is as follows.

Classificationcompany name
Manufacturing and sales companyTotaku Kogyo Co., Ltd., Steel String Equipment (Kogenkizai) Co., Ltd., Toyo Kako Co., Ltd.
Manufacturing companyTorii Kasei Co., Ltd., Osaka Steel String Equipment Co., Ltd.
Sales companyJapan Life Co., Ltd., Wex Japan Co., Ltd., Kurimoto Tekkosho Co., Ltd., Estee Engineering Co., Ltd., Asaba Seisakusho Co., Ltd.
  • Steel String Equipment Co., Ltd. closed in March 2006

2 Implementation status of JHS421

(1) The following are the companies and contents for which new facts have been discovered since the previous announcement.

company nameConfirmation status
Japan Life Co., Ltd.
(Atsugi City, Kanagawa Prefecture)
(Target construction 2 cases/2 bridges)
  • No test was conducted on φ55 products, and test data for other calibers from the same manufacturer were posted and reported. Some of the φ45, φ70, and φ80 test conditions (temperature, humidity) did not meet the standards.
  • Regarding the products of other manufacturing companies different from the above, we could confirm the test report by the Japan Society of Civil Engineers Concrete Standard Specification [Construction], but the test by JHS421 was not conducted.
Kurimoto Iron Works Co., Ltd.
(Nishi Ward, Osaka City)
(Target construction 2 cases/2 bridges)
  • It had posted and reported test data for products from other manufacturers.

(2) The additional survey results of Wex Japan Co., Ltd. and Totaku Industries Co., Ltd. are as follows.

company nameConfirmation status
Wex Japan Co., Ltd.
(Setagaya-ku, Tokyo)
(Target construction 1 case/2 bridges)
  • After confirming with the manufacturer, it was found that the manufacturer did not carry out the test.
  • Wex Japan Co., Ltd. posted and reported test data for products manufactured by different manufacturers.
Totaku Industry Co., Ltd.
(Yodogawa Ward, Osaka City)
  • No new facts have been confirmed.

(3) As a result of the survey, the following bridges have not been tested according to JHS421. (The Estee Engineering portion was announced on March 30)

 Bridge nameExtension
(M)		Construction namePE sheath
Sales company		location
Central Japan
Expressway
Corporation		Daini Tomei Expressway
  • Hamakita Viaduct
    (Take care of Hamakita)
    (Under construction)
1,414Daini Tomei Expressway
Hamakita Viaduct
(PC superstructure)
West In-bound line construction		Japan Life Co., Ltd.Shizuoka Prefecture
Western Japan
Expressway
Corporation		Kochi Expressway
  • Senbongawa Bridge
    (Senbon abashi)
    (In service)
223Kochi Expressway
(4 lanes)
Narukawa second bridge
(PC superstructure)
Construction		Japan Life Co., Ltd.Kochi Prefecture
Sanyo Expressway
Yamaguchi Junction
  • A ramp bridge
  • B ramp Daiichi Bridge
    (Under construction)
683Sanyo Expressway
Yamaguchi JCT
A/B ramp bridge
(PC/steel composite superstructure)
Construction		Wex Japan Co., Ltd.Yamaguchi Prefecture
Shin-Meishin Expressway
  • Ikeda Viaduct
    (Keiko Ikeda)
    (In service)
1,980Second Meishin Expressway
Ikeda Viaduct
(PC superstructure)
East (Part 2)
Construction

Second Meishin Expressway
Ikeda Viaduct
(PC superstructure)
Out-bound line construction		Kurimoto Iron Works Co., Ltd.Shiga Prefecture
Shin-Meishin Expressway
  • Asanogawa Bridge
    (Kawasaki Asano)
    (In service)
204

(4) The following are examples of JHS421 study conditions that were incomplete and the test report had not been submitted since the previous announcement.

company nameConfirmation status
Toyo Kako Co., Ltd.
(Otaru, Hokkaido)
(1 target construction/1 bridge)
  • Some of the test conditions (temperature, humidity) did not satisfy the criteria.
Asaba Manufacturing Co., Ltd.
(Minato Ward, Tokyo)
(1 target construction/1 bridge)
  • I was able to confirm the test report based on the JSCE Concrete Standard Specification [Construction], but the test report according to JHS421 was not submitted.
  • We confirmed the JHS421 test report this time, but there were some that did not meet the criteria for the test conditions (temperature, humidity).

The bridges corresponding to the cases of (5) and (4) are as follows.

 Bridge nameExtension
(M)		Construction namePE sheath
Sales company		location
East Japan
Expressway
Corporation		Hokkaido Crossing Expressway
  • Mukawa Bridge
    (Mukabashi)
    (Under construction)
396Hokkaido Crossing Expressway
Mukawa Bridge (PC superstructure)
Construction		Toyo Kako Co., Ltd.Hokkaido
Kan-Etsu Expressway
  • Oizumi Viaduct
    (Let's go to Japan)
    (In service)
2,056Kan-Etsu Expressway
Oizumi viaduct girder connection
Construction		Asaba Manufacturing Co., Ltd.Tokyo

3 Future response and recurrence prevention measures

(1) Implementation of emergency inspection
An emergency inspection is underway for all 342 bridges* under construction and in service that use PE sheath, and the inspection is scheduled to be completed by April 7, and the inspection is currently underway.

  • Breakdown: East Japan Expressway Co., Ltd.: 56 bridges, Central Japan Expressway Co., Ltd.: 158 bridges, West Japan Expressway Co., Ltd.: 128 bridges

(2) Ensuring the quality of the PE sheath

  • For the work of 2 (3), NEXCO employees will conduct JHS421 with the attendance and confirm the quality of the PE sheath. (In addition, all work related to PE sheath in the bridge under construction is completed.)
  • Regarding the construction under construction in 2 (5), the work related to the PE sheath will be temporarily stopped, NEXCO employees will conduct JHS421 with attendance, and will decide to resume the work after confirming the quality of the PE sheath.
  • In response to this event, we will promptly consider the test content and test conditions of JHS421.

(3) Immediate measures regarding the quality confirmation of JHS test specified by NEXCO3
As the immediate measure, we will not only confirm the test data to the construction contractor, but also obligate them to witness or submit the supporting documents, and we have already made known.

【reference】
The following are bridges that use PE sheath to which JHS421 is applied, which was ordered for construction after April 2004.

 In serviceNumber of bridges under construction
Number of bridgesExtension (m)Number of bridgesExtension (m)
East Nippon Expressway Co., Ltd.7About 4,30025About 8,100
Central Japan Expressway Co., Ltd.3About 1,00056About 24,300
West Japan Expressway Co., Ltd.25About 9,40029About 9,900

Note) The number of bridges is counted as one vertical line, and the extension is recorded separately for each vertical line.