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Kanazawa L.,Okumura Corporation | Yasui K.,Okumura Corporation | Yaginuma K.,Okumura Corporation
Journal of Environmental Engineering (Japan) | Year: 2017

We developed an active noise control (ANC) system which could be operated stably to the noise of moving (working) machineries. To the ANC system, we applied the feedforward control method with reference signal and without C. The control method estimated a predominant frequency in time domain and calibrated the phase delay. We checked the ANC by numerical simulation and laboratory experiment. The results are as follows. 1.By the numerical simulations, we confirmed the proposed method performed more stably and had the shorter convergence time of calibration, than the methods of general feedforward control and general feedback control. 2. Through laboratory experiments, we confirmed the ANC system with the proposed control method reduced the noise of construction machinery by about 10 dB.


Shahin H.M.,Islamic University of Technology | Nakai T.,Geo Research Institute | Ishii K.,Kajima Corporation | Iwata T.,West Corporation | Kuroi S.,Okumura Corporation
Acta Geotechnica | Year: 2016

To investigate the realistic ground behavior during tunneling, a new device has been developed. With the new device, model tests of tunnel excavation considering an existing tunnel and an existing building were carried out. Non-linear finite element analyses corresponding to the model tests were also conducted using FEMtij-2D software where an elastoplastic subloading tij model was used to describe the mechanical behavior of soil. Earth pressure distribution around the tunnels and ground movements during tunnel excavation depend on the distance and position between the twin tunnels. There is a significant effect of tunneling on the existing foundation of building even in the case where the tunnel is constructed in deep underground. The numerical analyses capture well the results of the model tests. © Springer-Verlag Berlin Heidelberg 2016.


Shahin H.M.,Nagoya Institute of Technology | Nakai T.,Geo Research Institute | Kuroi S.,Okumura Corporation
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability | Year: 2015

Two-dimensional model tests of shallow tunnels and the corresponding numerical analyses were carried out to investigate the interaction between the tunnel excavation and the adjacent foundation. The existing building loads are applied on the ground considering pile foundation. Here, the interaction effects are investigated varying the lateral distance between the tunnel and the foundation. The model tests were conducted using a newly developed device to simulate circular tunnel excavation. Non-linear finite element analyses corresponding to the model tests are also conducted using FEMtij-2D software where the subloading tij model is used as a constitutive model of soil. Surface settlement and shear strain of the ground, and earth pressure around tunnel are investigated. It is found that tunneling influences on the existing foundation when super structure exists within a certain distance from the tunnel.


Sasaki S.,Tohoku University | Shimada K.,Tohoku University | Yagai T.,Tohoku University | Tsuda M.,Tohoku University | And 3 more authors.
Physica C: Superconductivity and its Applications | Year: 2010

We have devised a magnetic levitation type superconducting seismic isolation device taking advantage of the specific characteristic of HTS bulk that the HTS bulk returns to its original position by restoring force against a horizontal displacement. The superconducting seismic isolation device is composed of HTS bulks and permanent magnets (PM rails). The PMs are fixed on an iron plate to realize the same polarities in the longitudinal direction and the different polarities in the transverse direction. The superconducting seismic isolation device can theoretically remove any horizontal vibrations completely. Therefore, the vibration transmissibility in the longitudinal direction of the PM rail becomes zero in theory. The zero vibration transmissibility and the stationary levitation, however, cannot be achieved in the real device because a uniform magnetic field distribution in the longitudinal direction of PM rail cannot be realized due to the individual difference of the PMs. Therefore, to achieve stationary levitation in the real device we adopted a PM-PM system that the different polarities are faced each other. The stationary levitation could be achieved by the magnetic interaction between the PMs in the PM-PM system, while the vibration transmitted to the seismic isolation object due to the magnetic interaction. We adopted a copper plate between the PMs to reduce the vibration transmissibility. The PM-PM system with the copper plate is very useful for realizing the stationary levitation and reducing the vibration transmissibility. © 2010 Elsevier B.V. All rights reserved.


Takeda A.,Okumura Corporation | Yamamoto H.,Hiroshima University
AIJ Journal of Technology and Design | Year: 2011

This paper presents the results of pile construction work for two steel-frame buildings. These buildings incorporate a method proposed by the authors in which the bottom end of a steel column is directly connected to the top end of a precast concrete pile. This method, which was developed for the construction of low-rise, long-span, steel-frame buildings, obviates the need for pile caps and underground beams. This method, however, requires greater accuracy pile construction than is required with conventional construction method. Hence, a stringent construction control value was specified for the work, and the outcome satisfied this value.


Takeda A.,Okumura Corporation | Yamamoto H.,Hiroshima University
ISEC 2013 - 7th International Structural Engineering and Construction Conference: New Developments in Structural Engineering and Construction | Year: 2013

The authors' previous report suggested the directly connected method in which a steel column is directly connected to a pile head and conventional pile caps and underground beams can be omitted. Laterally loading tests were conducted to study the behavior of the proposed connection. The relation between bending moment and rotation angle of the connection was expressed as an approximated curve. On the other hand, structural properties of a frame without underground beams are significantly affected by soil characteristics and are different from those of a frame having such beams. In order to compare the structural properties in these two situations, this paper analyzes an incremental load on a pile-ground-building frame by applying different parameters for ground conditions. Copyright © 2013 by Research Publishing Services.


Takeda A.,Okumura Corporation | Yamamoto H.,Hiroshima University
ISEC 2013 - 7th International Structural Engineering and Construction Conference: New Developments in Structural Engineering and Construction | Year: 2013

A construction method in which a steel column is directly connected to a pile head without pile caps and underground beams, is sometimes adopted for buildings over railroad tracks. The authors proposed the connection of a steel tube column and pile in which the bottom of the steel tube column is directly connected to the top of the pile head and where conventional pile caps and underground beams are omitted. The previous paper reported on the laterally loading tests that were conducted in order to check the behavior of the pile-column connection under lateral loading. In the other paper, the results of the tests were analyzed, and the property of bending deflection of the connection was expressed as an approximate function. In this paper, we conduct a finite element analysis in which test specimens for laterally loading tests are modeled, and the comparison is made between the results of the analysis and the tests. The purpose of this paper is to provide information required to determine an M - θ relation for the connections that are not tested, based on the results of the comparison. Copyright © 2013 by Research Publishing Services.


Okihashi T.,Okumura Corporation | Masuda Y.,Utsunomiya University
Journal of Structural and Construction Engineering | Year: 2012

Integrity of the tile finish on existing buildings is usually evaluated by the investigation of the exfoliation area and bond strength test. However, exfoliation sometimes occur again within the wall evaluated healthy by investigation. Therefore, we propose a method toassess the possibility of future exfoliation by measurement of the strain of existing wall tiles. The strain can be measured by strain gauges were affixed to the surface of the tile to be stripped. The results of the indoor and outdoor environmental test have confirmed that strain in bonded tiles can be estimated by the proposed test method.


Otsuka Y.,Okumura Corporation | Katsumi T.,Kyoto University
15th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering, ARC 2015: New Innovations and Sustainability | Year: 2015

Management of disaster debris treatment may include (1) progress in several work with over 100 laborers, (2) control of various mechanical equipment and machineries, (3) operation of more than 200 trucks. In order to properly support this management, Okumura Corporation has developed the "Disaster debris Treatment Support System (DTSS)" in 2011. DTSS has been accumulated a large amount of integrated data on disaster debris treatment in Yamada town, Iwate prefecture. 240,000 unit data obtained by the DTSS were analyzed to reveal the physical properties of debris and tsunami deposits. These data were too huge to analyze effectively. Spreadsheet software usually cannot be calculated 100,000 or more data. We solved this problem by applying a practical analysis software. The software called "Tableau" can be efficiently analyzed 100,000 or more data. The huge data was analyzed with Tableau. Results of the analysis of applying the Tableau revealed several weight characteristics of the transport phase in the debris and tsunami deposits. The results obtained will be expected to effective use as an experience to the time of future catastrophe.


Kurimoto M.,Okumura Corporation
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C | Year: 2010

Open loop control for the tower crane whose length is time varying is proposed to reduce the residual response amplitude. Different from traveling crane, because the system is described as 2 degrees of freedom system even in the case without variation of the length, a special strategy is required in the design of the acceleration pattern for the open loop control. By introducing the nonlinear time scales, we modify the acceleration pattern in the case without time-variation of the length proposed in our pervious research. We carry out the open loop control by applying the proposed acceleration pattern. We perform the numerical simulation for the analytical model whose validity is experimentally verified. The comparison of the residual amplitude under the conventional method and the proposed method shows the effectiveness of the proposed control method for the practical use.

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