In order to fulfill the growing needs for effective and efficient monitoring of construction and maintenance records, many challenging proposals are found to install RF devices (i.e. IC tags and wireless sensors) inside reinforced concrete (RC) members. This paper presents RF communication performance indices for these RF systems, focusing on the influences of steel-rebar and concrete located near the RF devices and reader-writer. Experimental evaluation using the above indices has shown that RF communication performance of RF device installed inside RC members does not hold addition rule for performance degradation caused by existence of concrete and re-bars. The results have also implied a possible method to assure RF communication performance before concrete placement. Repeatability of these results is assessed by comparative measurements of magnetic field strength under various conditions; communication distance, rebar arrangement , reader-writer types and RF device types.

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Mortar spreading methods, containing high density lithium nitrite, were applied on actual size concrete substrates and had been exposed along the coast of Okinawa for 19 years. During the above years, repression effects of flying salinity infiltration had been evaluated. It was found that nitrite ions permeated concrete structures promptly from mortar containing lithium nitrite. Understanding permeability of nitrite ions, lithium ions and chloride ions to concrete, authors provided diffusion equations to evaluate correlation between actual measurement and simulation derived values. It was inclined to show that diffusion coefficient of nitrite ions was greater than that of chloride and lithium, and that coefficient of lithium ions far much smaller than chloride: nitrite ions>chloride ones>>lithium ones. As a result it was shown that little flux rate and small diffusion coefficient of nitrite ions produced continuous supplying into concrete.

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This paper presents a seismic response control design method considering robustness on building structures with inter-story rotational inertia mass dampers. The proposed method employs normalized contour maps of H2 norm (root mean square) or weighted H2 norm of transfer functions of systems. The concept of interval analysis methods is applied to deal with structural uncertainties which are assumed to be bounded. The influence of variations in parameters has been easily evaluated by these contour maps.

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This paper presents the basic theoretical background of frequency domain decomposition (FDD) technique considering the estimation error caused by close modes. On the basis of the background, a FDD technique for proportional damping systems is proposed. The technique identifies the modal parameters from only the real part of the power spectrum density function matrix of response. In order to validate the proposed technique, numerical simulations with the conventional FDD technique and the proposed technique are carried out. The results show that the accuracy of the proposed technique is higher than that of the conventional one.

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This paper discusses on a control method of vertical micro-vibration of a beam using film type piezo-electric devices at the lower flange of the beam end. First, the actuator and the sensor characteristics of the film type piezo-electric device are shown. Secondly, the simulation method of estimating actuating force due to the device is shown using finite element analysis. Excitation test of the beam model using the device shows the validity of this simulation method. Finally, the experiment of controlling vertical micro-vibration of the beam using the film type piezo-electric devices as the actuator and the sensor is conducted, and effectiveness of the control system is proven.

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We develop the rupture directivity model and the correlation model with different periods for empirical envelope model of strong motions. The frequency-dependent envelope model is constructed using average and variance of group delay time from horizontal and vertical records of crustal earthquakes and subduction-zone earthquakes. The rupture directivity model for envelope is developed by the same modeling with that for response spectra by Satoh(2011). In order to solve the problem that the duration simulated by the envelope model is underestimated, we develop the correlation model with different periods for envelope by revising the correlation model for response spectra by Baker and Cornell(2006).

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The applicability of equivalent SDOF model for the prediction of nonlinear response of single-story asymmetric buildings is discussed in this paper. In the first part, a torsional index is defined based on each mode shape, and the relationship of parameters of asymmetric building model (eccentricity ratio, radius ratio of gyration torsional stiffness) and proposed torsional index is investigated. In the latter part, the applicability criteria of the procedure to predict the largest peak displacement of flexible-side frame of asymmetric buildings by using equivalent SDOF model is investigated. The results show that the predicted results agree well with that of nonlinear time-history analyses, only if the first and the second modes of asymmetric building model are predominantly translational mode; the torsional indices of the first and the second modes are smaller than unity. The contribution of the first modal response to the whole response is also discussed in this paper.

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When large earthquake beyond the input level in the aseismic design occurs, a base-isolated building may collide to the surrounding retaining wall. Then superstructure and base isolator are severely damaged and the building doesn't keep its performance. To address the subject, we are developing retaining wall of improved soil which reduces the response of the superstructure. This paper discusses collision experiments of base-isolated building model to developed retaining wall of improved soil. Furthermore analysis results by a lumped mass-spring model and 3D-FEM are also discussed to clarify the effect of modified retaining wall to response of building in a collision.

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Local damage of concrete structures, i.e. spalling, scabbing, perforation, would occur when concrete structures are impacted by high velocity projectiles. Scabbing and perforation must not occur in order to protect people and other properties inside of the structure from fragments scattering from the impacted structure. To reduce the local damage such as scabbing and perforation, it would be an effective measure to reinforce concrete with short fibers. Therefore, an experimental study on short fiber reinforced concrete plates impacted by a high velocity projectile was carried out, where the length, diameter and mix proportion of polypropylene short fiber were taken as main experimental parameters. As the result of study, it is confirmed that the local damage is effectively reduced by reinforcing concrete with polypropylene short fibers, and that the number of short fibers in a unit volume of concrete and the compressive toughness of concrete could be effective parameters on the reduction of local damage.

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The purpose of this paper is to describe the theoretical analysis for the shear stress distribution and the shear deformation with warping of orthotropic elastic beams of symmetrical cross sections. Especially, the shear deformations proportional to the shear force and inverse proportional to the shear modulus without minor terms in relation to bending stress in a Poisson's ratio is analyzed in this paper. For this purpose, introducing in-plane rigidity of the cross section with infinity, a number of degree of freedom of analytical models decrease considerably, and as a result the analysis is became easy. Thus, the general analysis technique about the symmetrical cross section of beams was able to be proposed by using this method. Furthermore, it is proved that assumption of the shear stress uniformly distributed along the horizontal direction of the cross section is equivalent to deal with the beam of G_zx=∞, the upper and lower bound of the shear deformations are obtained by applying to this model. As the example, the solutions of circular and square rhombic cross sections of beams, which are the shear stress distribution, the warping deformation and coefficients of Timoshenko's berm, are shown.

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With a recent development of computer technology, various kinds of excellent algorithms have been developed for optimization problem and new concepts in computer science have been successfully introduced into structural optimization such as genetic algorithm, simulated evolution method, simulated annealing method, dynamic tunneling algorithm, Boltzmann machine method, neural net work, artificial life and so on. In the field of structural design, much more attention on those structures with high redundancy has been focused from the viewpoint of safety as well as sustainable structural design, which in general requires a high cost. In this paper, the control design method of structural baring capacity is proposed to realize the low cost structures having precisely aimed baring capacity characteristics by using genetic algorithm (GA) as optimization tool.

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In this paper, the particle swarm optimization (PSO) and the artificial bee colony (ABC) are applied to the structural morphogenesis for free surface shell structure. In general, the structural morphogenesis is treated as the optimization problem. However, searching of the decent solutions to maintain diversity on the design variable space and the objective function space is important in the structural morphogenesis. The decent solutions have comparatively high evaluation containing a global optimal solution and local optimal solutions, and diversity of the design variable space. These solutions are a lot of free surface shell forms satisfying the design constraint, and a designer's idea will receive stimulation from those forms. Therefore, PSO and ABC implementing a manipulation for decent solution search are proposed here. First, the proposed procedures and these computational properties are described. Next, our schemes are applied to the structural morphogenesis for free surface shell structure. Here, the single-objective optimization problem is treated. The objective functions are the total and the bending strain energy. From numerical results, a lot of free surface shell forms with diversity and structural stability are shown. Finally, we show evaluation scheme for robustness concerning the structural form, and the relation between the decent solution forms and the structural robustness forms is clarified.

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The thick plywood has been developed in recent years, a new application method for architecture or other area is expected. In our past study, the sandwich panel with plywood and steel member is proposed for a new structural member. Then, we studied the compressive performance of that whole member. For expansion of versatility, all mechanical characteristics of thick plywood should be cleared. The bending or shear stress is cleared and enough for designing of the architecture, but the other values aren't enough.
In this study, we analyzed the buckling strength of thick plywood. Then we conducted compression tests with some slenderness ratio, λ, and experimental results were compared with some estimation methods.
As a result, over the 100 in slenderness ratio, the buckling strength could be estimated with Southwell-method or yield-strain-criterion. And the compression stress behaviour is expressed by Euler equation. In the case of under 100 in slenderness ratio, yield-strain -criterion is useful for estimating the plastic buckling strength. And the compression stress of lower limit is expressed by Tetmajer-method.

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In this paper, we propose the mechanical model of mud walls with initial failure in shear based on soil mechanics to estimate the relationship between strength and deformation. We also perform the full-scale static lateral loading tests of mud walls to grasp the fracture mode and the relationship between lateral loading and deformation. Finally, compared with the full-scale test results, the accuracy of estimation results is examined. From the results of these tests and estimations, it is found that the relationship between lateral loading and deformation of mud walls can be estimated with the mechanical model proposed in this paper.

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The structural system with the rotational foundation due to uplift at pile heads has an excellent seismic performance. However, in this structure, the weight of the structure has great influence on the restoring force characteristic. So, it is conscious that vertical ground motions may affect on the response of the superstructure. Also, the vertical acceleration due to vertical input motion may be important subject to be considered because the horizontal response of this structure causes the vertical acceleration due to uplift.
The purpose of this study is to research the influence of vertical ground motions on the vertical and horizontal response of the superstructure by the dynamic analysis. The effect of the shock absorber at the head of the piles on vertical acceleration is also investigated. The paper concludes that the influence of vertical input motion on horizontal restoring force characteristic is slight and the vertical acceleration of the structure is given by sum of those due to horizontal input motion and vertical input motion, respectively.

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The objective of this study is to clarify the relations between the effective length of a flange portion and bracing stiffness of beam-columns subjected to axial force and bending moment. The member is restrained against sway and rotation at the center. The buckling equations are derived by using the Rayleigh-Ritz method, and the effective lengths of members are calculated, taking the bracing stiffness ratio, loading condition and coefficient R as analytical parameters. After discussing the relations between the effective length and bracing stiffness, the effects on the effective length of loading condition and coefficient R are described.

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This paper analyzes the maximum relative displacement of adjacent structures in coupled vibration control structure. The ratio of the maximum relative displacement between two structures of damper connection and non-connection (R_d,rel) is focused and a reduction effect of the relative displacement by the connection of the oil damper is evaluated. Two mass models using coupled vibration control structure are analyzed and the trends of R_d,rel based on the period and mass of two structures and performance of the damper are clarified. Thereafter, the method of prediction of R_d,rel based on the least square method is presented and the accuracy of this method is verified by comparing the prediction results with the results of time history response analysis.

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Wave response experiments were performed to estimate the performance of three kinds of coupled system consisted of an elastic plate, a rigid plate and a fixed plate respectively. Vertical displacements, accelerations and wave pressures were measured on each plate model subjected to harmonic waves. The vertical displacements were measured using laser type sensor, acceleration responses were measured using high-sensitivity sensor for elastic and rigid plates at 9 locations respectively. And wave pressure distributions were measured using very small type pressure sensor that was built to order. Especially, regarding wave pressure, first of all wave pressure distributions on rigid and fixed plates were measured and compared with the past results. After that characteristics of wave pressure distributions on elastic plate were investigated from various point of view.

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System identification of structures set on shaking tables moving in horizontal direction with some pitching (rocking) motion is discussed about the following items :
1) The reason why the spectral ratio which uses, to calculate the input, the height of the response measuring point instead of the equivalent height is inappropriate for the transfer function of the structure.
2) The relation between the input for the transfer function and the equation of motion which controls the dynamic phenomenon of the structure.
3) Other references than the ones listed by the author.
4) What kinds of systems correspond to the transfer functions presented by the author?

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The method proposed by the writers is based on the pioneering work of the discusser who earlier proposed a different system identification method. The validity and usefulness of the writers' method are accepted by the discusser. However, the writers' comments on other possible methods are criticized by the discusser. The present answer clarifies contrasting difference of concepts by both parties, and provides a challenging opinion: the writers consider importance of accuracy of the method, justifying the use of the input/output relationship not necessarily qualified by the discusser as the true “transfer function”. Other points are also answered.

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