Journal of Structural and Construction Engineering (Transactions of AIJ)
Online ISSN : 1881-8153
Print ISSN : 1340-4202
ISSN-L : 1340-4202
Volume 79, Issue 706
Displaying 1-30 of 30 articles from this issue
  • Toshihisa UCHIDA, Shigemitsu HATANAKA, Naoki MISHIMA, Akihiro MAEGAWA
    2014 Volume 79 Issue 706 Pages 1709-1715
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    Main purpose of the present research is to clarify the chemical deterioration mechanism of porous concrete by CaCl2 solutions as a deicer. In the present study, cement paste specimens were fabricated with ordinary Portland cement and soaked in high concentration CaCl2 solution. Observation of deterioration process and X-ray diffraction analysis were conducted on both chemical deterioration products and binder exfoliated from aggregate surfaces. As a result, it was found that CaCl2 solution penetrated into binder, then produced deterioration product either in the interfaces of binder and aggregates causing the interface peeling, or right under the carbonated surface of binder causing stratified peeling. In both cases, collapse of porous concrete structure has been finally found. Also, it was found that surface of binder has high resistance against the CaCl2 attack in the existence of CaCO3 which was produced from hydration product Ca(OH)2.
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  • Haruki MOMOSE, Tetsushi KANDA, Keiichi IMAMOTO, Chizuru KIYOHARA, Kohs ...
    2014 Volume 79 Issue 706 Pages 1717-1727
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    Applying blast-furnace slag fine powder blended cement is an important option to achieve low carbon emission due to concrete materials in construction, and concrete structure with this blended cement concrete (BFS concrete, hereafter) is in great demand. However, BFS concrete is revealed that cracking resistance decreases at high temperature. Scope of this study is to experimentally investigate the mechanism of these phenomena. Restrained cracking experiments were conducted in three levels of ambient temperatures, 10-30 ℃, which consist of restraint cracking test, shrinkage test with non-restrained, mechanical property tests, and compressive creep test. The experiments showed that shrinkage cracking resistance of BFS concrete diminished at 30 degrees much worse than normal concrete. We found three sources for the diminishing trends: i) strength increase retention at relatively early age, which appears due to lack of hydration water, ii) autogeneous shrinkage increase at high temperature, iii) and low creep.
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  • Hisashi SUGIYAMA, Kensuke MITO
    2014 Volume 79 Issue 706 Pages 1729-1739
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    The strength of precast concrete is tested at production process with the test specimen made by the same curing method as an actual precast concrete element. However, the temperature history of precast concrete column with the large cross sectional size is different from that of test specimen. The difference in temperature history causes the difference of strength development between the two. The purpose of this study is to propose new types of test specimens cured under the same temperature conditions with the actual precast concrete column. The test specimens are covered with insulation and formwork according to the position in the precast concrete column.
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  • Ryota TOBARI, Masato ISHII, Toshiaki SATO, Haruyuki KITAMURA, Keisuke ...
    2014 Volume 79 Issue 706 Pages 1741-1750
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    Response control devices are widely used at the design of high-rise buildings owing to reduce the seismic response considering about the influence of long period ground motion, but these performances are degraded by excessive bending deformations. In order to improve response control performance, this paper describes an analysis method of effective damper deformations and a new structural system which amplifies effective damper deformations. It is confirmed that this system is able to highly reduce responses, particularly in acceleration and shear force, with a small amount of damper owing to high damping effect.
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  • Trial for accuracy improvement by addition of causal hysteretic damping model
    Naohiro NAKAMURA
    2014 Volume 79 Issue 706 Pages 1751-1761
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    Since it is well known that the internal damping of many materials is comparatively frequency independent, the Rayleigh damping model is often used for such kind of analyses. However, the accuracy and the availability of the model are not high. The author has studied and proposed some damping models for time domain analyses which are almost frequency independent. In this paper, a new damping model which is corresponding to the upgrade version of Rayleigh damping is proposed, based on these studies. The efficiency of the model is confirmed by applying it to example analyses.
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  • Ryosuke OKUNAKA, Yuji MIYAMOTO, Hisatoshi KASHIWA, Syotaro WATANABE
    2014 Volume 79 Issue 706 Pages 1763-1771
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    When large earthquake beyond the input level in the aseismic design occurs, a base-isolated building may collide with surrounding retaining wall. Then superstructure and base isolator are severely damaged and the building doesn't keep its performance. To address this subject, we study response of a base-isolation building in collision including oblique impact to retaining wall. This paper discusses experiments of base-isolated building model taking oblique collision into account. Based on the results of experiments, we analyze oblique collision in detail by 3D-FEM. Furthermore response of a real-scale base-isolation building is studied when building collides with retaining wall. As a result of these studies, we show the influence of oblique collision on response of base-isolation building, retaining wall and surrounding soil during extra-large earthquake.
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  • Takumi KOMIYA, Makoto KANDA, Hiroki KOBAYASHI
    2014 Volume 79 Issue 706 Pages 1773-1781
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    This paper describes fundamental characteristics of wind response control of structures using the inertial mass. The change of mass, damping parameter, natural period, Scruton number are defined using the inertia mass ratio γ. Using a condensation single-degree-of-freedom model of a super high rise building, the response is simulated under white noise and external wind force. From the results, reduced effect of the acceleration response is found. The aerodynamic stability of structures by the inertia mass is investigated by means of modified hybrid vibration technique. It is found out that the inertial mass has effect of aerodynamic stability of structures.
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  • Kenji FUJII
    2014 Volume 79 Issue 706 Pages 1783-1793
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    The applicability of equivalent SDOF model for the prediction of nonlinear peak response of multi-story asymmetric building subjected to bi-directional excitation is discussed in this paper. In the first part, the formulation of two independent equivalent SDOF models representing the first and second modal responses is summarized, and the critical conditions of which the asymmetric building should satisfy are discussed. In the latter part, nonlinear time history analyses of three four-story torsionally stiff (TS) and three torsionally flexible (TF) asymmetric buildings are carried out and these results are compared with the predicted results. The results show that the proposed procedure satisfactorily predicts the peak response displacement of a only TS asymmetric building. Therefore the applicability of equivalent SDOF model discussed in this paper should be limited to TS buildings. The classification of TS buildings can be made from the torsional index defined based on mode shape.
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  • Hiroaki YAMANAKA
    2014 Volume 79 Issue 706 Pages 1795-1803
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    Applicability of Markov Chain Monte Carlo (MCMC) method in Rayleigh wave phase velocity inversion in shallow soil is examined. Numerical examination was conducted using synthetic phase velocity. Frequency distributions of S-wave velocities and thicknesses of the sampled models were used to estimate optimal model and its uncertainty. The shallow S-wave velocity model was well reconstructed from the inversion. The uncertainties of the parameters are linearly related with the observational errors. The sampled models were used to estimate uncertainty of 1D amplification factors. We furthermore applied the inversion method to actual data from microtremor explorations in damaged area during the 2007 Noto-Hanto earthquake. It is concluded that the MCMC inversion method is effective to estimate optimal model together with their uncertainty.
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  • Kensaku KANEKO, Shojiro MOTOYUI
    2014 Volume 79 Issue 706 Pages 1805-1815
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This paper proposes the practical evaluation methods for the natural period and the vibration mode in one story steel structures with a roof not considered as rigid. The roof consisting of beams and braces is regarded as one dimensional continuum beam with the elastic supports. The vibration characteristics are solved based on the Rayleigh-Ritz method and summarized with the ratio of two kinds of stiffness and mass ratio. The proposed methods are verified comparing with the finite differential method and applied to the frame analysis for a gymnasium with end planes stiffened by braces.
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  • Kazuhiro KANEDA, Shoichi TSUKUNI, Tsuyoshi HONDA, Akihiko UCHIDA
    2014 Volume 79 Issue 706 Pages 1817-1824
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    For liquefaction countermeasure based on grid-form deep mixing walls, the grid interval has conventionally been designed using the excess pore water pressure ratio or the FL value, and conditions under which liquefaction does not occur in the ground within the grid. However, in the case of seismic motions with a long duration, such as that which occurred during the 2011 earthquake off the Pacific coast of Tohoku, used as a design seismic motion, the increase in the excess pore water pressure in the ground within the grid becomes greater than that for a seismic motion with a shorter duration and an equivalent acceleration level. Centrifuge model vibration testing and numerical simulations were conducted to obtain the knowledge required for a performance design focused on settlement occurring in the ground within the grid. The sands with different relative densities are usually in a structured, overconsolidated and anisotropic state. The Super/subloading Yield Surface Cam-clay model with rotational hardening (SYS Cam-clay model) is powerful for incorporating these features. We found that the numerical simulations reproduced the experimental data well. It is indicated that there is the possibility of settlement evaluations under earthquake.
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  • Masatoshi WADA, Kohji TOKIMATSU, Masamichi SAWAISHI
    2014 Volume 79 Issue 706 Pages 1825-1833
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    In order to evaluate the bearing capacity of closed end screwed pile with spiral wings, installation and loading tests were executed in uniformly graded sand in a calibration chamber. The experimental factors include the spiral wing diameter Dw (Dw/Dp=1.4-1.7, Dp :pile diameter) and the spiral pitch P (P/Dw=0.8-1.2). The test results and discussions have shown that : (1) The bearing capacity of the pile can be determined by the shear strength of cylindrical surface whose diameter is Dw, (2) There is a fairly-well defined correlation between skin bearing capacity and installation torque, and (3) The skin bearing capacity can be estimated using the torque acting on the pile shaft.
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  • Naoko SUZUKI, Takuji HAMAMOTO
    2014 Volume 79 Issue 706 Pages 1835-1845
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    A monitoring-simulation combined method is presented to evaluate the structural performance of building foundations. The proposed method has been applied to an existing piled-raft foundation. The continuous evolution of consolidation settlement is monitored at limited measurement points of interest using four kinds of sensor: differential settlement gauge, strain gauge, thermometer and optical level surveying. The monitoring resolution in space is refined through settlement simulation analyses using global and local models. The global model is concerned with the spatial distribution of soil settlement over the foundation mat, whereas the local model deals with the change in axial force of each pile and the dissipation process of excess pore water pressure induced by settlement. Based on measurement and analysis results, the usefulness and limitations of the proposed method are discussed.
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  • Kenji YAMAMOTO
    2014 Volume 79 Issue 706 Pages 1847-1856
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This paper proposed a technique of shape modification of single-layer reticulated shells for increasing linear buckling loads. The sensitivity analysis of the linear buckling load of a single-layer reticulated shell with respect to the nodal coordinates was performed, and the distributions of the sensitivity coefficients were examined. As a result, it was found that the distribution of the absolute value of z direction component of each buckling mode resembles the distribution of the sensitivity coefficients corresponding to the buckling mode. This tendency was utilized, and the technique of adding distribution of the absolute value of the buckling mode to a shell shape was proposed. The proposal technique was applied to several reticulated shells with various forms, and the efficiency was confirmed.
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  • Toshio TAKAGAKI
    2014 Volume 79 Issue 706 Pages 1857-1867
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    A cantilever-supported shell that is cut out from a circular cylinder is investigated. It is found that the shell with the specified boundary shape has a membrane stress field, which is obtained by solving analytically the differential equations. In order to confirm the results, typical examples are solved numerically using FEM based on Galerkin type weak form. Then, the effect of the plate bending neglected by membrane theory is investigated. Furthermore, it is verified that the influence caused by difference between the idealized boundary condition of the membrane theory and the exact fixed boundary condition of FEM is very small. Therefore, this shell is said mostly in membrane stress state, and has shell-like advantage on shape, space and ecomomy.
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  • Rokhyun YOON, Yasushi SANADA, Takumi AKAHORI, Suguru SUZUKI, Hiroshi K ...
    2014 Volume 79 Issue 706 Pages 1869-1878
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This paper reports cyclic loading test results of three one-story, one-bay reinforced concrete moment resisting frame specimens. Two of the specimens have secondary walls which are monolithically constructed or structurally isolated by seismic slits. Consequently, the isolated wall as well as monolithic wall increased the strength of moment resisting frame. This was caused by a small amount of tie bars which were provided for the isolated wall at the wall/frame boundaries. Therefore, a calculation procedure is presented based on the principle of virtual work mainly to evaluate the lateral strength of moment resisting frame with the isolated wall.
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  • Hideyoshi WATANABE, Motoi TAKEDA, Atsushi HATTORI
    2014 Volume 79 Issue 706 Pages 1879-1886
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    In this study, flexure and shear tests were conducted to clarify the structural performance of reinforced concrete beams formed by joining together two full precast beam-end elements at the mid-span using grout mortar with splice-bar joints of longitudinal bars. A total of seven specimens were used in the tests. The parameters were the strength of the longitudinal bars, the transverse reinforcement spacing, and the length of the lap splices. This study revealed that current evaluation formulas can be used under the proposed full precast joint system to evaluate the bond splitting strength of the lap splices.
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  • Yasuji SHINOHARA, Kazuhisa MURAKAMI
    2014 Volume 79 Issue 706 Pages 1887-1897
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    Experiments were performed on ten reinforced concrete beams having second layer-cutoff bars to study the influence of the bond reinforcement upon bond splitting strength and cracking behaviors. The second layer bars have three different cutoff lengths and been reinforced by transverse bars of various configurations including opened type for easy construction. Test results showed that the bond stress at the tip of second layer bars were increased rapidly and degraded before peak loads, and that reinforcement effect of opened type bars were reduced to 60% of closed type bars. FE analyses for three type transverse bars were also carried out to investigate reinforcement effect against bond splitting only due to the wedge action of deformed bar, and provided valuable information about the effect of the transverse bars on the bond splitting behaviors.
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  • Kikuo IKARASHI, Yuki OHNISHI
    2014 Volume 79 Issue 706 Pages 1899-1908
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This study aims to develop approximate formulas to calculate the elastic buckling strength of H-shaped beams with continuous complete restraint on the upper flange by theoretical analysis, and to examine the coupled effect between plate local buckling and lateral buckling under restraint. As a result, the following conclusions are reached: (1) The elastic lateral buckling strength of H-shaped beams with continuous complete restraint on the upper flange is expressed by the equation proposed in this study. (2) The effect of continuous restraint to plate local buckling strength is little. (3) Continuous restraint on the upper flange increases lateral buckling strength but the coupled effect between plate local buckling and lateral buckling under restraint can decrease buckling strength.
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  • Kosuke SATO, Kikuo IKARASHI
    2014 Volume 79 Issue 706 Pages 1909-1918
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    The purpose of this study is to present approximate formulas for elastic local buckling strength of square hollow section members under biaxial bending shear force and axial force. For this purpose, buckling analysis considering coupled effects of plate elements and complex stress conditions by bending, shear, and compression is conducted using energy method. Effects of determinants of the buckling strength, boundary conditions, aspect ratio, and stress conditions of the plate elements are understood. Simple approximate formulas for the coupled local buckling strength corresponding to boundary conditions at both ends, shape and stress distribution with respect to the members are presented.
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  • Hitoshi OZAKI, Yoshinao KONISHI, Ryota MATSUI, Toru TAKEUCHI
    2014 Volume 79 Issue 706 Pages 1919-1929
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    Buckling restrained braces (BRBs) are widely used in seismic regions as ductile seismic-resistant and energy dissipating structural members. On the other hand, the risk of overall flexural buckling under cyclic axial loading with initial out-of-plane drifts simulating the bi-directional effects of a ground motion has been pointed out. In this regard, series of formula for securing the BRB out-of-plane stability has been proposed in previous studies. However, the actual ranges of each index that make up this series of formula are not clear for practical engineers. In this paper, these index values are clarified by carrying out the research studies of various BRBs and their connections that have been used in actual design. Based on these results, a simple method that can evaluate the out-of-plane stability condition of BRBs with various connection conditions is proposed.
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  • Study on web-clamped beam-to-column connection Part 1
    Keita ARAKI, Jun IYAMA, Piao SHIWAN
    2014 Volume 79 Issue 706 Pages 1931-1940
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    A new type of beam-to-column connection, named the "web-clamped connection", has been proposed by the authors as an alternative to conventional welded connections. This connection is designed to transfer all the stress from the beam to the column via the specially designed attachments and the shear plate. In this paper, the internal stress distribution in the attachments and the shear plate is numerically investigated to clarify the internal force transfer mechanism in this connection. A parametric study of the connection is carried out through finite element simulations with various strength ratio of the panel zone strength to the attachment strength. The results show that both bending moment and shear force are mainly transferred by the attachments whether the connection has the shear plate or not.
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  • Toru TAKEUCHI, Xingchen CHEN, Ryota MATSUI
    2014 Volume 79 Issue 706 Pages 1941-1949
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    Recently, various controlled rocking systems have been proposed in seismic design to prevent damage concentration and to achieve self-centering against a wide range of input ground motion intensities. However, there are several obstacles to overcome before they can be applied to actual buildings, such as the requirement of large, self-centering post-tensioned (PT) strands and special treatment at uplift column bases. This paper proposes a non-uplifting spine frame system with energy-dissipating members without PT strands; its self-centering function relies on envelope elastic moment frames. The system is applied to an actual building constructed in Japan. Conventional shear damper and uplifting rocking systems with PT strands developed in prior studies are applied to the same building structures, and the performance of the three systems, including damage distribution, energy dissipation, self-centering, robustness against severe earthquake, and irregular stiffness, is compared and discussed through numerical simulations.
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  • Takaya HONDA, Shunya ONO, Minoru YAMANARI, Koji OGAWA
    2014 Volume 79 Issue 706 Pages 1951-1960
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    This paper presents a seismic design procedure to estimate the residual deformation of steel frames with hysteretic dampers when main frames do not yield under earthquake excitations. Dynamic response analysis was carried out on single-degree-of-freedom systems with various structural parameters. The authors have already proposed two methods to estimate the residual deformation, we examined these two methods and proposed a new method through numerical work. Finally, the paper concludes that the proposed new method is also applicable for multistory frames as well as one mass-spring systems.
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  • Kazuhiro FUJISHITA, Ryota MATSUI, Toru TAKEUCHI
    2014 Volume 79 Issue 706 Pages 1961-1971
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
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    In retrofitting multistory RC buildings which have uniaxial eccentricity, it is important to control torsional displacement to assure safety of structure under seismic input. In this study, elastic response of each frame of uniaxial eccentric three dimensional model is evaluated by using a pair of equivalent independent lamped mass models. The easy damper distribution method proposed for plane frames in previous paper is applied to these pair of lamped mass, and damper distribution in each plane frame are determined. The validity of proposed method is confirmed by applying to three-dimension model of typical Turkish RC building which has uniaxial eccentricity and weak stories.
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  • -In case of one-sided sliding type-
    Tomohiro KINOSHITA, Yosuke KANESHIRO, Yuji KOETAKA, Keiichiro SUITA, K ...
    2014 Volume 79 Issue 706 Pages 1973-1982
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This paper presents conditions to prevent global buckling of pin-ended tube-in-tube buckling restrained braces. When one end of the restraining member is rigidly connected to the pin joint and the sliding joint is adopted at the other end, the deflection of the brace makes an asymmetric curve and the local deformation of the restraining member may occur at the sliding joint. The method to calculate deflection of the core member and bending moment of the buckling restraining member is led theoretically. Validity of proposed methods and conditions to prevent global buckling are verified through parametric study on cyclic loading tests and FEM analysis.
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  • Hiroyuki TAMAI, Fumitaka SEO
    2014 Volume 79 Issue 706 Pages 1983-1990
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    A shear panel dampers consisting of stiffeners and a panel surrounding four flanges are used as aseismic dampers for buildings in Japan. Cracks can easily form in a shear panel damper when the panel undergoes shear buckling during cyclic loading caused by a severe earthquake. The damper's plastic deformation capacity can be enhanced by installing several vertical and horizontal stiffeners on the panel. Plastic deformation capacity means the amplitude of cyclic deformation angle under which the damper's strength keeps its designed yield strength. Overall shear buckling of the panel causes sudden deterioration of the damper's strength. Hence, overall shear buckling in a panel must be prevented to ensure that the shear panel damper maintains its yield strength up to an assumed deformation angle. Chusilp and Usami proposed an optimum stiffener flexural rigidity ratio, which defines the stiffener's sectional properties in which subpanels divided by stiffeners reach shear buckling before the panel undergoes overall shear buckling. However, the terms of the Fourier series in the Reghleigh-Ritz method were 6x6, and the accuracy of the plate buckling coefficient is not satisfactory. The torsional rigidity of the stiffener is not taken into account in the analysis. Application conditions are restricted so that the vertical and horizontal stiffeners must be the same. Hence, we derived an equation for the shear buckling eigen value problem considering the effect of the stiffener's torsional rigidity from the principle of virtual work. Then, the optimum stiffener flexural rigidity ratio was calculated by the regula-faisi method using various combination numbers of vertical and horizontal stiffeners. Then, the required sectional properties of the stiffener are clarified for a shear panel damper.
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  • Reiichi SUZUKI, Ryu KASAI, Tetsuo SUGA, Tadao NAKAGOMI
    2014 Volume 79 Issue 706 Pages 1991-2001
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    It is suggested asymmetry detail which has the non-scallop (access hole) method for upper side and the reinforcement welding around toe of the scallops for lower side of the beam. The purpose is to develop the detail and joint method has easiness to product and high capacity of plastic deformation suitable for on-site. In addition, new developed backing-less method which is overhead welding and overlay using the special consumable was combined instead of the backing plate which is jointed to groove bottom of the end of beam flange. Full-size beam-to-column assemblies applied these methods had high capacity of plastic deformation. This improvement mechanism is regard as reduction stress concentrations and controls of these balances by shape of overlay metal formed by arc welding. As the leg length of reinforced weld become increase, strain ratio of outer against center become decrease in the groove weld width of the beam end.
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  • Shigeru TAGO, Masaomi TESHIGAWARA, Akihiro NAKAMURA, Ayumi OHNISHI
    2014 Volume 79 Issue 706 Pages 2003-2011
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This study proposes the evaluation method of arrangement and the strengthening effect of the steel framed brace for existing middle to high rise I-shaped apartment complex buildings designed before 1981. The proposed method considers the displacement and strength ratio of flexural to shear. The applicability and effectiveness of the proposed method is verified by static load incremental analysis and dynamic response analysis of an example model building.
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  • - Model of restoring force characteristics -
    Toshiyuki FUKUMOTO
    2014 Volume 79 Issue 706 Pages 2013-2021
    Published: December 30, 2014
    Released on J-STAGE: January 30, 2015
    JOURNAL FREE ACCESS
    This paper proposes a new practical model of a restoring force characteristic on the panel zone within steel beam-to-concrete filled square steel tube column moment connections for predicting the elastoplastic behavior of the panel zones including strength reduction after ultimate strength. The proposed model for a skeleton curve is provided as a multi-linear model having a cracking strength point, a yield strength point, an ultimate strength point and strength reduction points for 95%, 90% or 80% of ultimate strength. The skeleton curve model up to the ultimate strength point is based on the previous shear force-deformation model proposed by the writers, while the deformations of these strength reduction points is provided as new regression formulations obtained from previous test results. The writer proposes a new hysteresis loop model including stiffness reduction. The proposed models agree approximately with experimental results up to large deformations.
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