This report presents the results of experiment which aime is to establish the test method for water content of fresh concrete based on the heat dry method with microwave range. Water content of fresh concrete is expressed as follows. W=W_d+W_c+W_a where W: water content of fresh concrete (mortar) W_d: weight of water which is evaporates by drying W_c: hydrated water with cement W_a: weight of absorbed water in aggregate Various factors which would affect the duration and accuracy of the measurement were investigated in this experiment. The results are as follows. 1. The duration of the period required for the water to be evaporated by drying was about 40 minutes. 2. The weight of the water which is hydrated with cement during heat-drying is 1 to 1. 5 % of the weight of the cement. 3. The accuracy of the test when the heating time is 20 minutes is -5 % -0.5 %.

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As fracture is separating material, so it is possible to appreciate that fracture is chemical reaction of solid. Chemical thermodynamics is used for a fundamental theory of chemical reaction, so it is posible to predict the effect on applying the thermodynamics to the analysis of fracture of hardened cement paste. The purpose of this report is to analyze the breaking phenomenon of specimens by the application of the two big laws of thermodynamics. The outline of results is as follows. (1) It is proved that the potential energy of the steel ring breakes the hardend cement paste ring. (2) It is proved that the potential energy of the hardend cement paste ring is going to react on decleasing. (3) As the results of the experiments, quantity of breaking energy of mortar is concerned with quantity of sand in mortar.

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The phenomena of crack development as it relates to reinforcement near the corners of window openings in reinforced concrete walls was researched and a design method for determining the relationship of crack width and quantity of reinforcement was developed. The results were based on the data of experiments with full scale specimens (which contained various types of reinforcement and were observed over a period of two years and seven months) and other existing documents. In experiments with full scale specimens, many types of reinforcement were compared. Ladder type reinforcement resulted in the na-rrowest crack width and diagonal bar reinforcement had the next narrowest and the other samples had considerably wider cracks width. Ladder type reinforcement and diagonal bar reinforcement was used in opening corner on external walls of reinfoced concrete in M. building. The cracks width was measured 2 years 1〜2 monthes after concreting. Ladder type reinforcement resulted in the narrower average crack width than diagonal ber reinforcement, so ladder type reinforcement is more effective another reinforcement.

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As one of the factors which influence long-term deflections on reinforced concrete slabs after being cracked, the slippage of tension steel at fixed edges has been generally accepted. From previously published test data, it is obvious that the influence on the slippage of tension steel is so large that it can not be disregared when compared with the influence on creep and shrinkage of concrete. However, a method for the quantitative estimation on the change of slippage of tension steel with time is still not clear. In this paper, the formulation is shown on the basis of bond stress-relative slippage relation and then the validity of this formulation is examined by comparing analayzed results with experimental results. Finally, even though equations solved by elastic analysis are used as the equation for the calculation of the slippage of tension steel under sustained design loading, it is shown that the analyzed results which are given by these equations are sufficiently useful for structural design when the results of elastic analysis are compared with the results of elastic-plastic analysis. Furthermore, it is shown that L=35 d may be used as the anchorage length in the case of utilizing a calculated equation for the slippage of tension steel on pull-out specimens.

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A method is proposed to analyze beam-collapse R/C interior joints under seismic actions. Stresses along the periphery of the joints are modelled as shown in Fig. 2. Shear resistant mechanisms are considered as shown in Figs. 3 through 12. The tensile stress of horizontal shear reinforcement in a joint shall be the maximum when the bond of the top beam bars is at the border of enough or not.

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The authors have carried out an investigation in Sendai City and throughout Japan of the results of tensile tests on a random sample of gas-pressure-welded joints and have reported the ratio of the test pieces that failed at the joint, the distribution of tensile strengths of these test pieces, and other items. However, although the construction categories of all of the test pieces were known, according to the test organizations involved the history of all of the test pieces had not been investigated, and there was the possibility that among the test pieces there were some whose history was unknown. To eliminate any uncertainty resulting from this, it is important to carry out an investigation on the results of tensile tests on test pieces whose history is known. Accordingly, the test pieces of known history used for this report were tensile test pieces produced in the "Gas Pressure Welding Operator's Skill Qualification Test" by Japan Pressure Welding Society. The report covers the test results of 36 297 test pieces between 1982 and 1986. Because all of the test pieces investigated in this report have knwon histories, the data obtained can be considered to provide new information which was not available from previous research on the estimation of the reliability of the tensile strength of gas-pressure-welded joints. Furthermore, it is considered that because the conditions under which joints are produced in the qualification test are presently considered to be close to the ideal, the results of this investigation provide fundamentel data on the estimation of the reriability of the tensile strength of gas-pressure-welded joints produced under ideal condition.

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The flexible-stiff mixed structure is a frame which consists of stiff elements with high rigidity and a high energy absorption capacity, and flexible elements with low rigidity and a large elastic deformation capacity. The rigid elements can be a source of energy absorption, whereas the flexible elements allow a structure a stable development of deformation. Thus, this type of structure can be a preferable structural form against earthquakes. When the first story of a multi-story structure is so designed as to absorb the total energy input exerted by an earthquake, the other stories can be released from restraints required for securing the energy absorption capacity. It is demonstrated that the seismic response of flexible-stiff mixed structures with energy concentration in the first story can be simply predicted by taking account of the energy balance of structure.

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It is an important trial to observe hydrogen induced crack (HIC) initiation and propagation after welding and to analyze accumulation of diffusionable hydrogen around crack tip under stress by finite element method (FEM). Specimen of HT-80 was deposited with a low hydrogen type electrode, and welded specimens was loaded under the optical microscope observation. The HIC initiated at the center of weld bead and propagated into weld metal and heat affected zone. The HIC propagated intermittently through HAZ in a brittle manner.

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Plastic hinge models based on the concept of flow rule and a yield surface represented by generalized stresses are often used for elastic-plastic analysis of steel space frames. However, since the plastic deformations in plastic hinge are obtained directly by flow rule in those models, it is impossible to introduce distinctly the generalized strain hardening modulus which relates the infinitesimal generalized stress increment to the infinitesimal generalized strain increment as the strain hardening modulus in the finite element analysis of a continuum. This is a main factor that reduces the accuracy of the analitical results. A procedure to form an elastic-plastic tangent stiffness matrix of tubular members is presented in this paper. The generalized strain hardening modulus can be used directly to estimate the behavior of plastic hinge in the procedure and the effect of finite deformations of a frame are taken into account also. Numerical examples are made for two kind of tubular beam-columns and the results are compared with available theoretical and experimental results to verify the proposed method.

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The values of annual maximum windspeed measured at the weather stations in Japan have been decreased from 1960. Several investigators explain that this is due to the decrease of the number of severe typhoons afflicting Japan. However, this explanation is suspect because the reduction of windspeed also appears in the values of annual mean windspeed and daily maximum windspeed. The authors hypothesize that this tendency to reduced windspeed is closely related to the increasing of ground roughness. We investigated the total volume of the building around the weather stations in Japan and we assert that the yearly variation of the ground roughness is greater than we expected. We show that the building density has increased radically since I960 and is closely correlated with the yearly variation of windspeed. We suggest a possibility that the reduction of windspeed is mainly caused by the increasing of the ground roughness. Then the annual maximum windspeed is corrected taking into account the variation of the ground roughness, and the values for any return period are discussed.

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A series of tests were performed on steel cylindrical shells subjected to internal pressure, bending and shearing forces. Conclusions are summarized below. (1) The lower limit of buckling load can be described as follows. When σ_h/σ_γ≦0.3, _bσ_m=_bσ_o+(0.56 _0σ_<cγ>-_bσ_m)(σ_h/σ_γ)/0.3…(10.1) When σ_h/σ_γ>0.3,_bσ_m=0.8 _0σ_<cγ>(1-σ_h/σ_γ)…(10.2) where _bσ_m: the maximun extreme fibre stress at the bottom of shell σ_h: hoop stress due to internal pressure σ_γ: the yield point stress _bσ_<mo>: the lower limit of buckling stress without internal pressure _0σ_<cγ>: compressive buckling stress without internal pressure in the axisymmetric mode (2) The _bσ-θ curve under the monotonic horizontal loading is simply identified to be a skelton curve as shown Fig. 3, where ba is the extreme fibre stress at the bottom of the shell and θ is the overall inclination of the shell. The stationary value termed by _bσ_<0.02> in the range of large deformation can be calculated by using equation (6). _bσ_<0.02>=50 σ_γ/(γ/t)…(6) where _bσ_<0.02>: _bσ at the point of θ=0.02 γ: external radius t: wall thickness (3) Under repeated loading, the relation between _bσ and θ is easily costructed from the skelton curve on the basis of the same hysteresis rule as is applied to the case without internal pressure.

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In this paper, we introduced a new earthquake-like random excitation model with non-stationary amplitude and with non-stationary and non-white spectral characteristics. In view of the non-predictability of earthquake excitation, we placed emphasis on realizing its model in terms of the mean value and variation, and developed a new analytical technique for the mean value and variation of the 2nd order statistical moment response and the displacement response spectra of linear structural systems. Numerical calculation was carried out as an example. The predominant angular frequency parameter has had a remarkable influence on the structural response to such a degree that the c. o. v. of the structural response was the same as or more than the c. o. v. of the predominant angular frequency, while very little influence of the shaping factor parameter has been observed on the structural response. The convergence of a variation response calculation was examined, and the poor convergence was recognized only over the resonant frequency of structural systems.

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This paper is dealt with the analysis of the in-plane elastic buckling of regular polygonal frames which are supported elastically in member directions and subjected to inward concentrated non-follower loads uniformly at all the joints, as approximate models of cylindrical lattice shells under the action of external pressure. The buckling type of this case is bifurcation from uniform prebuckling state because this structure is symmetric to periodic rotation. So, in this paper, the periodic property of the polygonal structures is utilized for the buckling analysis. The main conclusions are as follows. 1) The buckling mode and the buckling load can be expressed in simple formula if the number of members is infinity or members are perfectly rigid. 2) On the condition the number of members is constant, the variation of the ratio between the elastic spring constant and the effective bending rigidity of frames gives all the periodic buckling modes. Especially, in the case of pin-jointed frames, buckling modes are zigzag for the case of stiffer member, and member buckling modes for the other case. 3) The buckling load determined by rigid body rotation, wavy buckling or zigzag buckling, is not affected by the ratio of the member bending softness in the effective bending softness, and the case of rigid members gives the almost lowest limit value of the buckling load. On the other hand, the buckling load determined by member buckling can be estimated by the Euler buckling of pin-supported column. 4) In the condition the effective rigidity of frames and the circumcircle radius of frames are constant, rigid body rotations or lower wavy buckling is scarcely affected by the variation of number of members, but zigzag buckling or higher wavy buckling is considerably affected by the variation of number of members. The zigzag buckling load of the pin-jointed frames can be expressed in Eq. (57). 5) For practical design, the buckling load of frames composed of elastic members can be estimated by member buckling or the buckling load formula for the case composed of rigid members with Eq. (54) for the value of Eq. (55) and Eq. (57).

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In the tensile structures, configuration stability of structures depend on the existence of the initial tensile stress. Therefore the initial stress is situated as an important structural member in the structures. But in the traditional structures, an initial stress is not regarded as an important structural members except pre-stressed or post-stressed concrete structures. However there are such structures in the traditional structures which depend on the presence of the initial compressive stress and they must be regarded as the stress to be an important structural members. So we call these structures "Compression Structures" in this paper. This paper is described with the stability of configuration of compression structurs. And the purpose of this study is that we survey the trditional structures from the stand point as initial stress is an important structural member, and specially, we investigate the effect that self-weight of the structural member gives the configuration stability of structures. If we classify the structures by the sort of initial stress, we can understand the structures well as ever, and we will be able to expect the posibility of finding new structural system through the concept of this procedure.

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The purpose of this paper is to clarify dynamic properties of a hilly area with topographic irregularity and a reinforced concrete structure (4-stories) located on that area, by observational and analytical approaches. In the observational approach, microtremores installed on a real fill ground with topographic irregularity, were observed along a measurement line. On the other hand, in the analytical approach the real fill ground is idealized into a visco-elastic body by boundary element method. This model ground is composed of a half space with a cavity, and the cavity represents the fill ground. The structure is also idealized as a visco-elastic body. For incident SH waves, frequency response analysis is carried out in this system, and frequency response properties of the model ground and structure and obtained. Results are summarized as follows: (1) The hilly area has a local amplification effect. Namely it has some uni-predominant frequency and the amplitude factor increases according to the thickness of a hilly area. (2) The stiffness of the hilly area is greater than that of the equivalent horizontal soil layer. (3) Frequency response properties obtained by boundary element method well correspond to results of microtremor observations. (4) In the case of the structure on the hilly area, stress concentrations are created in each part of the structure on boundaries of the fill ground by the local amplification effect.

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