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Minakata N.,Kyoto University | Nishiyama S.,Okayama University | Yano T.,Kyoto University | Tezuka H.,KUMAGAIGUMI Co. | Aoki K.,KUMAGAIGUMI Co.
International Multidisciplinary Scientific GeoConference Surveying Geology and Mining Ecology Management, SGEM | Year: 2013

This paper presents some results of studies on application of a monitoring system using Micro Electro Mechanical System (MEMS) sensors in order to measure deformations of a retaining wall. The MEMS sensors have three advantages which are compact, lightweight, and inexpensive. In this paper, the authors propose that using the supports system, the precision of the sensor network system gets higher than before. Using wireless communication between the transmitter and receiver in this system, the data observed by the MEMS sensor is transmitted to the base station directly, and the distance is approximately 500m with good visibility and about 300m with vegetation. The authors applied this system to monitoring an actual retaining wall under construction. It is concluded from the result that the MEMS sensor could measure very small deformations of the retaining wall and the small change of an inclination had been affected by a series of external factors such as rainfalls and an earth pressure from the back of the wall. © SGEM2013 All Rights Reserved by the International Multidisciplinary Scientific GeoConference SGEM.

Sato H.,Kumagai Gumi Co. | Miyazawa S.,Ashikaga Institute of Technology | Yatagai A.,DC Co.
CONCREEP 2015: Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures - Proceedings of the 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures | Year: 2015

Thermal stress in a gravity concrete dam was simulated by three dimensional FEM analyses taking autogenous shrinkage of concrete with full-sized aggregate into account. It is proved from experimental results that external concrete with blast-furnace slag Portland cement exhibits autogenous shrinkage of 130×10-6 at one year after casting, which is much larger than moderate-heat Portland cements with and without fly ash. Calculated thermal stress in upstream-downstream direction at the center of the concrete blocks near foundation rock is increased by autogenous shrinkage if concrete with large autogenous shrinkage is used. Thermal stresses in dam-axis direction at upstream and downstream surfaces are increased by the difference in autogenous shrinkage strains between internal and external concretes, if blast-furnace slag Portland cement is used. It can be said that autogenous shrinkage which simultaneously occurs with thermal strain should be taken into account in order to control thermal cracking during construction period which can adversely affect the stability, water tightness and durability of concrete gravity dams. © ASCE.

Mori T.,Kumagaigumi Co. | Endou M.,Kumagaigumi Co.
AIJ Journal of Technology and Design | Year: 2014

Pulling test was carried out in order to examine the pulling out characteristic of permanent ground anchors of compression type having a large diameter settled in hard clay and soft rock. It was found that the level of the ultimate frictional stress was equal to the value of anchors which has usual diameter in the past, and the ultimate frictional stress was possible to presume by using the value of undrained shear strength, and the displacement of anchorage zone at the pulling out time was about 10mm.

Mori T.,Kumagaigumi Co. | Ogawa A.,Kumagaigumi Co.
Journal of Structural and Construction Engineering | Year: 2016

We have carried out a long-term measurement of prestressing force in permanent ground anchor which were employed to buildings. On the measurement results, we confirmed the time change properties of prestressing force and analyzed the quantity of each decrease by three known factors, relaxation of pulling materials, creep of the anchor fixation ground and subsidence right under the foundation which was tense and fixed ground anchors. Furthermore, we inspected the prediction method that was assumed at the time of the design, of prestressing force which was held 60 years later.

Nishigaki S.,Mazaran Co. | Saibara K.,Kick Co. | Kitahara S.,Kumagaigumi Co.
31st International Symposium on Automation and Robotics in Construction and Mining, ISARC 2014 - Proceedings | Year: 2014

Mechanized earthworks for post-disaster reconstruction largely forks into unmanned construction at hazardous working sites and manned one at less hazardous sites. In order to avoid secondary disasters, it is significant and required to compensate operator's realistic sensation in order to enhance spatial awareness in the mechanized earthworks. The mechanized earthworks consist of a series of discrete works, which are sometimes independently and at other time interactively performed by different workers and managed by small and medium contractors. Generally, a variety of construction machines made by different manufactures are used there. On the other hand, diverse machine guidance systems come from different vendors. Most of them are self-contained and constitute an independent unit in and of itself. Here, are demanded inexpensive and easy-to-use software systems with sensors capable of easily mounting and demounting. The software systems of those should be not embedded in specific construction machines but available to multiple ones. To overcoming problems like those, our primary efforts target on fabricating information modelling system for mechanized earthworks by utilizing open source software. The information modelling here means a process involving acquisition of field data and feedback of relevant digital representations of physical and functional characteristics of works in progress. This paper presents framework of field data acquisition and exploratory spatio-temporal visualizations, enhancement of spatial awareness, enhancement of communication, and conclusions with a discussion of the contributions included in this paper. Finally, some open problems are also pointed out.

Mori T.,Kumagaigumi Co.
AIJ Journal of Technology and Design | Year: 2010

Measurement of prestressing force in permanent ground anchors, which was used in order to prevent the building from floating by the lift of ground water or in case of an earthquake, was carried out over the long period of time. When the prestressing force of 60 years after was presumed based on the measurement result, the effective prestressing rate was set from 0.84 to 0.95, and was around 0.9. As a result of comparing the calculated value and measurement value, it was found that the adoption value at the time of a design was appropriate.

Nishigaki S.,Kick Co. | Saibara K.,Kick Co. | Kitahara S.,Kumagaigumi Co. | Iwasaki H.,Kumagaigumi Co. | And 2 more authors.
Proceedings of the 28th International Symposium on Automation and Robotics in Construction, ISARC 2011 | Year: 2011

This paper describes the ICT-based work management to enhance collaborative works and interactive communication, and to grasp significant information in order to support unmanned construction for post-disaster restoration. Firstly, this paper reports the unmanned constructions that have been and are being done in the Unzen restoration project. Secondly, are presented the collaboration, communication, construction and intelligent management (C3IM), which is a comprehensive, web-enabled system to enhance collaborative works and interactive communication, and to grasp significant information in order to support the unmanned construction. Thirdly, are described staple functions of the ICT-based work management Fourth, are reported applications of the ICT-based work management to the unmanned construction of multilayer sediment control dam using sediment forms in the Unzen restoration project. Finally, it shows remarks.

Japan Atomic Energy Agency and Kumagai Gumi Co. | Date: 2011-12-09

A sensor with aging function is provided wherein installation space for an apparatus to perform an aging process and the number of apparatuses can be reduced which enables easy and reliable aging processes and can improve measuring accuracy and enhance measuring reliability of the sensor. The sensor with aging function 10 is attached, through a bonding agent 15, to a high temperature measuring object 14, comprising a block body 12 constructed by integrally forming a sensor main body 11 and an electric heater 13 disposed in a manner to be close to the sensor main body 11 using a molding process, wherein a bonding surface on which the bonding agent 15 is applied is formed on the measuring object 14 side of the block body 12.

Japan Atomic Energy Agency and Kumagai Gumi Co. | Date: 2011-12-09

A sensor and bonding agent for the sensor wherein thickness of the bonding agent interposed between the sensor and measuring object can be kept uniform to maintain uniform bonding force of the bonding agent and a peeling phenomenon of the bonding agent occurring due to a difference in thermal expansion between the measuring object and bonding agent and/or between the bonding agent and the sensor can be prevented. The sensor is attached, through the bonding agent, to a high-temperature measuring object, include a sensor main body having a detecting section, a block body constructed by integrally forming the sensor main body using a molding process. The block body is made of a ceramic-based bonding material that the same as a material forming the bonding agent and, on a side of the measuring object of the block body, a bonding surface of the bonding agent is formed.

Kumagai Gumi Co., Japan Atomic Energy Agency and Fibex Co. | Date: 2010-08-25

A reinforced sensor with an optical fiber woven into a fabric, comprising a fabric formed in a manner that a weft yarn is woven thereinto in a direction substantially perpendicular to a warp yarn, wherein an optical fiber is included in at least either one of fibers of the warp yarn and the weft yarn. The optical fiber may function as a FBG sensor.

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