This paper reports on the investigation of thickness of cover concrete through nondestructive test for a quantity of member samples from 18 buildings of reinforced concrete structure constructed actually in standard methods as well as on the analysis of its distribution and fluctuations. While the preceding paper reported on the actual state of deviation within a member and that among members, this paper analyzes the influences of “additional cover concrete in design phase” and “that in construction phase”. As a result of this, it has been disclosed that any free movement of reinforcing bars due to the said influences leads to increase in deviation within a member as well as that among members.

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This paper proposes a mix design system of vinylon fiber-reinforced porous concretes with exact continuous voids and fiber content. The voids and the fiber content in mix proportions are proposed as factors of the mix design. The correction parameters of the fiber content in the mix proportion are also investigated in consideration of the target voids and water-cement ratio. The applicability of the proposed mix design system is confirmed in the case study of the concrete with the target voids of 20% and the fiber content of 0.5% using vinylon fiber having the length of 40 mm.

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The corrosion of reinforcement is fatal risk for structures, but is difficult to observe the state of corrosion on the concrete surface at an early stage. In this paper we have employed electrochemical noise measurement and Mahalanobis-Taguchi system to develop a non-destructive technique for corrosion detection. Electrochemical noise measurement is a technique involving the acquisition processing and analysis of electrochemical noise data. Mahalanobis-Taguchi system is a technique of pattern recognition. Electrochemical noise was measured and then analyzed by means of Mahalanobis-Taguchi system.
As a result, it was found that changes in the corrosion state agree with rust amount could be monitored by electrochemical noise measurement and Mahalanobis distance. These parameters are therefore found applicable as indices for corrosion diagnosis.

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We proposed a procedure to establish a model of dynamic fault rupturing for predicting strong ground motions under the constraints by empirical relations among fault parameters of the surface and subsurface faults such as the fault length, the dislocation on the surface, the ruptured area, the seismic moment, and the short-period level of the acceleration source spectrum. As an example, given the depth of the seismogenic layer 4 to 18 km deep and the earthquake magnitude of 7.2, we evaluated 14 model parameters of the dynamic fault rupturing. We confirmed that the results of the dynamic fault rupturing simulation based on this model satisfied the empirical relations adopted prior to the simulation.

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Shaking tables have limitations for the maximum displacement, velocity and acceleration. This paper proposes a shaking table test technique to expand the reproducible high frequency range of the table and realize large acceleration. This technique uses two systems: one is the pounding system and the other the high-frequency system. The pounding system hits the high-frequency system first and a free vibration occurs on the high-frequency system. Repeating the pounding, the free vibration of the high-frequency system continues and large amplitudes can also be achieved. To validate this technique, a shaking table test was conducted, and the test results show the efficiencies of the proposed technique.

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The present paper discusses on a dynamic seismic performance index of structure, _d I_s, and a dynamic ductility index, _d F, of a brace installed in the longitudinal direction of sport halls. Based on the result of the elasto-plasitc dynamic analysis depending on various input levels, _d F and _d I_s are re-studied. As numerical parameters, a yield base shear coefficient of braces of substructure, C_y , and a capacity limit deformation of braces as well as hysteresis types are considered, and their effects on _d F and _d I_s are investigated. Furthermore, the method of estimation for _d F is proposed using an absorbed energy principle, and the validity of the proposal method is proven by comparing the responses of the dynamic response analysis with those based on the proposed method.

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For bolted connections in timber structures, calculation method based on European yield theory is well known and widely used in the world. On this equation, we need some material properties, embedment strength of wood, yield strength of bolt and each size of specimens. Based on some test results, the strength on the latest standard in Japan announced in public. On the other hand, failure modes in wood aren't considered enough. On this study, we conducted bearing tests based on BS EN 383 and 3-point-bearing test, using end-distance, bolts diameter and wood species as tests parameter. We arranged the specimens with or without clearance between specimen and loaded-steelplate to observe crack behavior. Additionally tension-loaded bolted specimens were analyzed by failure modes and the bearing strengths were calculated according to EYT equation.
As a result, 2%off-set strength was corresponding with the crack-starting-strength on bearing tests. The cracked-strength of bolted connection was almost the same with the calculation result with 2%off-set strength.

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Full-scale shaking table tests were carried out at E-Defense to evaluate the seismic performance of a traditional wooden residential structure. The specimen was a post-and-beam frame with a plan dimension of 5.91 × 11.82 m and height of 7.53m. A key feature of the specimen was the oversized beams and columns. The design seismic load resistance was provided entirely by mud plaster walls. The beam-to-column joints were achieved by an oak peg using no metal fasteners. Under BCJ-L2 shaking, the first story exhibited a story drift of 3.7%, and one of the corner columns cracked. At that stage, many of the mud-plaster walls had crumbled. The maximum recorded base shear coefficient was 0.5.

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According to the moment resistance frame substitution model, the assumed stress state about the N value calculation method to estimate the required tensile force of column's top and bottom joints was explained. The general solution about the tensile force of column's top and bottom joints was derived with the moment resistance frame substitution model and the shear panel substitution model in which the bending stiffness of the beams and the axial stiffness of the joints were considered. It was found by using the general solution with these substitution models that the coefficient “Bi”, which is multiplied by the shear wall magnification factor in N value calculation method, was affected by the bending stiffness of the beams and the shear wall length. As a result, the validity and coverage of the coefficient “Bi” became clear. In addition, the approximated values of “Bi” corresponding to each shear wall length were shown in Table 3 for the practical structural calculation as the result of this theoretical study.
The tensile force of column's top and bottom joints in various conditions can be obtained accurately by the calculation method of this theoretical study.

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Formulae to predict shear force-drift angle relations of compressive bracing shear walls with arbitrary wall length are proposed in this paper, taking into consideration the equilibrium of forces and friction acting on end of the braces. These formulae are derived assuming the major component of deformation of compressive bracing shear wall is the compression of both ends of a brace into a girder and a sill. These formulae are verified with element tests of brace ends and tests of bracing shear walls.

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This paper extends a kinematic model named nine DOF model proposed by one of the authors which could predicts the moment capacity and moment at balanced failure of reinforced concrete beam-column joints. The original model is applicable to interior beam-column joints of which the geometric and loading conditions are equal and symmetric about a diagonal line of the joint. The extension reduced the limitations and allows for different sectional dimensions and reinforcement of beam and column and different forces on the beams and columns. The results from the extended model compared to experimental results and the model gave accurate prediction.

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The shear failure of reinforced concrete shear wall brought by diagonal strut inside of wall panel can be classified into two types regardless of before or after flexural yielding: 1) shear failure of wall panel; and 2) compression failure of concrete at the bottom of boundary column. In reinforced concrete shear wall, transition of neutral axis which has greatly effects on the shear strength under plastic deformation is not considered in evaluation of deformation capacity on present standards. This paper presented a method to evaluate the deformation capacity of reinforced concrete shear walls considering failure mode based on following assumptions: 1) area of compression field is being reduced in accordance with increasing plastic deformation; and 2) shear failure occurs when the stress of the compression field reaches to the compressive strength of concrete at the wall panel or boundary column. The presented method was verified by applying to 33 test results; however, evaluation of confined effect by the boundary columns and ultimate strain of concrete should be considered.

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Elastic buckling strength of columns in steel moment resisting frames had been studied for uniform vertical loads by many researchers. But in Japan where seismic loads are significant, the axial forces corresponding to overturning moment due to seismic loads should be considered in design. In such load conditions, the column that suffers larger compressive force can be laterally supported by other columns which sustain moderate or tensile axial forces. This paper proposes a method to estimate elastic buckling strength of columns in moment resisting frames under anti-symmetric vertical loads on beam-to-column nodes. The accuracy of estimation is confirmed by comparing to the results obtained by geometrical non-linear analyses or eigenvalue analyses for portal frames.

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A new-type hysteretic damper composed of a slitted steel plate and buckling-restraining wood panels is proposed. Cyclic loading tests on five damper element specimens, including one without buckling restraining panels, are conducted. The buckling-restrained specimens behave in a stable manner with the equivalent viscous damping ratio ranging from 0.3 to 0.4, while the hysteresis loops after the ultimate strength are pinched due to the steel plate's local buckling in the vicinity of slit ends. In the specimen with the thinnest wood panels, large kinks are formed close to corners of the steel plate, and in another specimen, where cracks are formed between the slits, strength deterioration is observed. Associated FEM analyses that represent the specimens show good agreement with the test results.

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In this paper, composite beams reinforced by cover plate partially attached on the lower flange are proposed in order to save steel weight. To avoid distortion raised by welding and minimize the fabrication cost, the cover plate is welded to the lower flange only at both ends and two intermediate points. Design formulae for calculating strength and elastic stiffness of such composite beams are developed based on equilibrium of stress and compatibility of deformation.
Full-scale vertical loading tests are performed on three composite beam specimens. The cover plate of the first specimen is welded at both ends and two intermediate points, while that of the second one is welded continuously. The last one is a conventional composite beam without a cover plate. The test results show that the welding types give little effects on strength and elastic stiffness of the beams. The proposed formulae show good agreement with the test results.

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The authors are studying a facade system which is integrated architectural, environmental and structural engineering. The system consists of not only structural elements, but also architectural or environmental elements such as claddings. Therefore, some structural system which secures the seismic performance of claddings will be needed. In this paper, a new structural system, called as the trigger system which enables that two seismic performances both of structure and claddings, is proposed, and the efficiency of the system is discussed. The trigger system consists of a trigger mechanism and buckling-restrained brace. First, the outline of the trigger system is described. Next, a seismic performance of a building with the trigger system is analyzed. The trigger system is effective in keeping seismic safety. And, a detail of the trigger system is shown. Finally, an actual size test of the trigger system is conducted to confirm the performance.

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