Based on the data of strength obtained from experiment, corrections of proportioning strength of mass concrete using lowheat type cement are studied. In case that the age for quality control of the strength of concrete in structure using low-heat portland cement is 28 days, curing under low temperature makes the strength of concrete in structure be lower than expected strength. And for several combinations of the age for proportioning strength of concrete and the age for quality control of the strength of concrete in structure, influence of difference between the two methods of proportioning design is clarified.

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Visco additives are one of the indispensable substances for performing the actual procedures of cementitious materials production by extrusion moulding in factories, which are also the most effective in determining the cost of the products. This paper deals with a series of experiments for examining the effects of viscosity of the additives. As a result, the following technological items are clarified from the viewpoints of reducing drying shrinkage strains; 1) The medium viscosity, that is four thousands MPa・s is the most appropriate in comparison with the lower and higher ones. 2) The residual strains after moisture and drying repetitions inversely appeared in case of the lower viscosity and higher one. 3) Increasing trend of drying shrinkage strain amplitude is experimentally related to that of residual strain.

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There is no end of poor surface layers of concrete ground works with insufficiency of the execution circumstances and using soft concrete. In this case, even highly efficient finishing materials cannot make floors come up to the requirement performance. Essentially, it is the reason which is given no clarification to the quality due to the characteristics of concrete and the execution circumstances. This report describes results of field investigations on the characteristics of concrete and the execution circumstances. It shows the concept of the quality index on the surface layers of concrete ground works with giving an instance.

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Evaluation methods of formaldehyde emission from building materials have been standardized in both JIS A 1460:2001 (Desiccator method) and JIS A 1901:2003 (Small chamber method). Although the desiccator method can not give formaldehyde emission rates directly, it has been applied to wood-based building materials and wallpaper in their product standards. On the other hand, the small chamber method can give formaldehyde emission rates directly; however, it needs costlier apparatus and longer time for measurement in comparison with the desiccator method. In this context, formaldehyde emission from coating materials and wallpaper were evaluated by using the two methods and the data obtained were compared with each other. It was confirmed that there was high correlation between the data obtained by the two methods. Therefore, the formaldehyde emission rates obtained by using the small chamber method can be estimated from the data obtained by the desiccator method.

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The effect of weathering on fatigue resistance of a repaired area in a concrete crack by epoxy resin was studied Mortar specimens repaired by two kinds of epoxy resins were exposed in Yokohama for 3 years to make clear the actual degradation by weathering. The effective weather elements on decrease in fatigue resistance were discussed and heat and moisture were extracted as effective ones. Two kinds of accelerated degradation tests composed of solo element of heat and complex ones such as heat and moisture were carried out. The results showed the complex degradation test is needed for accelerating actual degradation, and the test conditions was furthermore discussed.

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In this paper, the response in the earthquake of the seismic isolated building with the U-shaped lead damper is examined. Effect of the difference of the method which models restoring force characteristics of the damper on the response characteristic of seismic isolation structure is examined by carrying out the numerical analysis, and the features are clarified. It is considered that as a result of the numerical analysis, it is possible that the restoring force characteristics of the U-shaped lead damper estimates the necessary response by modeling at the simple bi-linear, for the design at the enough accuracy.

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This paper describes an analytical evaluation of strong ground motions in Kobe City during the 2000 Tottori-ken Seibu earthquake. A numerically efficient finite-difference technique combining nonuniform and discontinuous grid spacing is applied for the 3D wave propagation analysis. The entire soil region is divided at particular depth into two regions modeled by different nonuniform grids. Grids in the bottom region for bedrock are coarser than the top region including sediments, which largely cut down on the number of grids. The computational steps for calculation can be reduced to one-sixth by the coupling effects of the grid reduction and variable time steps. Three-dimensional analysis simulates well the velocity seismograms recorded in both mountain and sedimentary sites in the Kobe area. The PGVs in sediments gradually amplify from the basin edge to Osaka bay, which can be seen in both observed and synthetic motions. Site amplification near the basin edge is found to be different for the predominant period of the incident seismic wave.

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This paper discusses accuracy of a global damping model for approximate analysis of the structural system with either viscoelastic damper or oil damper. The model utilizes equivalent period and damping ratio of the system specifically determined at the resonant state, and, unlike the original system, it possesses neither frequency-dependency nor localized damping mechanism. By using different ground motion records, accurate time-history analyses are conducted using numerous one-mass systems with the dampers, and the results compared to those using their global damping models. With some modifications depending on the damper type, the global damping model is found to produce reasonably accurate results, thereby warranting its extended use for a conventional response spectrum analysis or simplified time history analysis.

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This paper shows two methods of reducing from a multi-story building to the equivalent single degree of freedom system (ESDOF) to improve the capacity spectrum method used in the calculation of response and limit strength provided in the Building Standard Law Enforcement Order of Japan. One is a mode-adaptive pushover analysis method, which uses a stiffness-dependent lateral force distribution at each loading step without the eigenvalue analysis, and the other is a method using modal decomposition procedure together with earthquake response analysis. Applying both methods for 4 and 12 story RC buildings, the validity of the methods and the earthquake response characteristics of ESDOF system are examined. Based on the latter method, an evaluation method of the higher mode effect in story responses is also proposed.

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The large deformation/post-peak behavior analysis method of concrete beams and columns considering bond-slip of reinforcement is developed. The analytical procedure is capable of predicting the response of concrete beams and columns under axial force and biaxial bending in the material and geometrical nonlinear domains, including post-peak behavior using the incremental arch length method. The paper gives an outline of the nonlinear analysis method which includes the effect of bond-slip of reinforcement to handle the large deformation region, and three numerical examples are given to illustrate the use of the proposed procedure.

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In general, the mechanical characteristic between concrete and reinforcements can be assumed to be perfectly bonded in the analyses of concrete members in elastic region. However, the asumption is not appropriate for concrete members with un-bonded tendons. To date, there has been little research considering the vibration analysis of concrete members with bond-slip. This paper deals with the free vibration analysis of reinforced concrete beam members considering the bond-slip of reinforcements. In this paper, first, the authors derive differential equations governing bending vibration of reinforced concrete beams in elastic region based on principle of virtual work. Then, the finite element formulation of the problem is implemented. Finally, several numerical examples with various bond moduli are shown to examine the effects of the bond-slip on the bending vibration of concrete beams.

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An optimal design method considering effects of spatial variation of input ground motions is applied to structural design of space trusses. Wave passage effect, loss of coherence (incoherence effect) and variation of local soil condition (local effect) are investigated in this paper. The optimal design problem is formulated for finding optimal cross-sectional areas of members so as to minimize the total volume under strain constraints. After the optimal design method is outlined, optimization is carried put for doublelayer space trusses under different local soil conditions. The effects of the soil condition, soil spring stiffness at supports and types of structural foundation on the optimal solutions are revealed. The effects of wave passage and incoherence are also discussed. Accuracy of optimization results is examined through time history response analyses.

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In the failure of R/C L-shaped shear walls in buildings, a bi-directional displacement and rotative distortion are generated. A shear force also affects the columns not only in the loading direction but also in the loading right-angled direction as they resist the displacement in both the loading direction and right-angled direction. In this paper, the loading right-angled direction shear force which affects the column-induced flexure failure of L-shaped shear walls in the building is examined. As a result, it was found that the evaluation method of this paper and 3-dimensional frame analysis almost correspond with each other.

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This paper proposes the new reinforced concrete structural members, which have excellent deformation capacity without severe damage. The structural members have steel sleeves covering longitudinal reinforcing bars of almost the same length as the depth of members, at the edge parts of members. In the area of about one forth of the length of steel sleeve, where is far from the fixed end of a member, the longitudinal steel bars are integrated with the steel sleeve by joint mortal. In another area, the longitudinal steel bars are free inside steel sleeves. The seismic tests of seven reinforced concrete beams verified their splendid seismic performance.

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Collapse or severe damage has been observed in many RC residential buildings with soft story at the previous earthquake disasters. Hence development of an effective structural control technology is one of the urgent tasks for residential apartments in the urban area. However, most of the conventional structural control methods for soft story buildings stuff a space with structural elements such as RC walls or response control dampers. This paper proposes a new technique for structural control of RC buildings with soft story by using ductile short columns as response control devices placed beside the existing columns at the soft story. The objective of the response control is upgrading safety as well as reparability for damage mitigation without partitioning off the spaces at the soft story. The main role of these devices are to increase story shear capacity to reduce response drift of the soft story, and to support axial force due to overturning moment in order to reduce axial force acting on the soft story columns. Results of the inelastic earthquake response analysis indicate that yielding of the soft story column can be successfully prevented since the response control devices work effectively.

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A lot of applications such as FEM have been developed by many investigators, and served for the precise analyses. Although the small structural elements can be analyzed precisely, it is hard to analyze whole structure in the same precision. If we can unify precise applications under internet environment, we can analyze not only huge structures so precisely, but also can analyze coupling effects of various phenomena. As the first step to realize above plan, this paper deals with the elasto-plastic structural analysis of a steel braced frame by networking several personal computers. The results including buckling behavior were shown.

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This paper presents the results of analytical studies in order to evaluate flexural strength demand for beam-to-column connections in earthquake-resistant design. The authors have developed a computer program based on the one-dimensional finite element method in which a generalized constitutive relationship considering isotropic hardening and kinematic hardening is incorporated. Numerical analysis of steel wide-flange beams is carried out under various loading sequences similar to seismic response. The results are summarized as a method to predict the maximum bending moments of beams, taking into account the maximum story drift angles.

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As an important keyward, the authors use "allowable stress of the ground" which can not be found out in any publications of AIJ excepting regulations such as Notification No.l 113. About 30 years ago, there was a hot argument between members of AIJ and a government official on introducing this term into the former Notification No. 111. The opinions of members were almost as follows; Different from artificial member, there does not exisist allowable stress in the case of the ground. So that, by using the concept of allowable bearing capacity divided the ultimate bearing capacity by a certain safety factor, or allowable bearing power considering settlement, the base area of footing is calclulated. But the government official slicked his opinion that it is allowable stress because permitting stress per unit area, and the argument broke down. Under the state of this situation continues until today, the discusser wants to ask why the authors use " allowable stress of the ground" which is not a scientific term and does not exist actually?

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The investigation was made for how to use the two technical terms of the allowable bearing capacity and the allowable stress in analysis of the foundation on the multi-layered ground. The allowable bearing capacity disappears in Recommendations for Design of Building Foundations of 2001; however, the three limit states in a load-settlement curve are defined in limit states design. The allowable stress is derived from the ultimate bearing capacity in taking account of the safety factor.

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