This paper describes the result of long-term crack-inducing experiment on half-scaled four RC wall specimens. Compared to conventional crack control joints, the proposed crack control joints with crack-inducing bars could contribute to inducing shrinkage cracks within the joints more uniformly. As a result, the maximum crack width in the joints with crack-inducing bars was smaller than that in the conventional joints. A crack width estimation method proposed by Ohno et al. could accurately estimate the maximum crack widths of the specimens.
The floor slabs directly above footing beams are parts of a reinforced concrete building that require insulation. A construction method using thermally insulating extruded polystyrene foam, which does not require removal, is frequently employed to simplify slab formwork dismantling in the underground pit. Foam formwork has different mechanical characteristics to plywood formwork. However, these characteristics are still not well understood. In this study, the stiffness of polystyrene formwork is evaluated by conducting bending and bearing pressure tests using a component specimen. Moreover, a full-scale experiment is conducted under the loading conditions present during actual construction, to investigate whether the true deformation can be assessed based on the stiffness value obtained from the component tests.
This paper discusses a measurement method of unit weight and water content of concrete using radio isotope meter. Concrete members with different unit weight were measured them at the age of 7, 28 and 91 days. As a result, it was found the following things. If the unit weight of concrete is high, the measurement accuracy of the unit weight and water content using radio isotope meter is low. Inserting the radio isotope source a sleeve, it can reduce variations in measurements. The drying of concrete read from radio isotope meter. The calibration curve between the unit weight of concrete and the attenuation of radiation was created.
For a further improvement of formwork construction, it is necessary to know actual state because of the important role of the formwork contractor. Therefore, the purpose of this study is to reveal the actual state about component materials and erection of conventional formwork by the questionnaire survey targeted to formwork contractors of Kanto and Kinki area. As a result, this paper showed the actual state of formwork construction about structural calculation for strength and rigidity of formwork, erection type of formwork by studs and separators, regional characteristics of component materials of formwork.
A small-diameter drilling tester developed by the authors is one of the slight-destructive testers, with which the damage of materials tested can be very small. To apply the tester for checking the strength of compound materials e.g. Portland cement mortars, concretes etc., a series of experiments was carried out 1) to avoid the ill effect of cement powder discharged around a drill, 2) to avoid drilling coarse aggregates, and 3) to know the best magnitude of pressure for drilling. As a result, it is clarified that the testing method may be improved by considering the obtained data.
We have investigated three actual RC buildings, which were built about 50 years ago, to clarify the carbonation inhabitation effect of the finishing mortar on the progress of concrete carbonation. It is found from this investigation that the differences of carbonation progress between the concrete outside wall in one orientation and that in other orientations can be evaluated in carbonation rate coefficient. The investigation of durability of other actual RC buildings should become more accurate with the simplified analytical method described in this paper.
We have conducted a survey on one RC building that was built 53 years ago for such detail conditions as reinforcement corrosion, thickness of cover concrete, carbonation depth, and water content in concrete. These conditions of the building surveyed were sorted out by structural members, orientations of concrete wall and environmental conditions to understand actual conditions of the reinforcement corrosion, so that we can study the cause of the reinforcement corrosion.
In 2011 the Great East Japan Earthquake, many buildings prevented continued use by damage of foundation in spite of minor damage of superstructure. For continued use of buildings, seismic performance of foundation is important, not just seismic performance of superstructure. In this paper, I will report a case assumed that pile damage is caused by complicated dynamic characteristics of superstructure, and a study of the case used microtremor measurement, ARX model, and multi-degree-of-freedom system.
In this paper, characteristics of damping ratio of RC/SRC high-rise buildings are discussed from identification of strong motion data. The following results are shown: 1) From the identification result of strong motion, damping ratio type is similar to instantaneous stiffness proportional. 2) First viscos damping ratio from strong motion is from 1.5% to 3.0%. 3) Higher viscos damping ratios are almost same value as first damping ratio and are not proportional to natural frequencies.
Three scenario earthquakes, such as Nankai trough mega earthquake, the 1923 Kanto earthquake, and North Tokyo bay earthquake, are selected at Tokyo bay area, based on the seismic hazard analysis and so on. Earthquake ground motions at engineering bed rock are evaluated by the Hybrid synthesis of ground motions derived from the stochastic Green’s function method and the 3D-finite difference method. In addition to the conventional moderate and severe earthquakes (Level 1 and 2), extreme earthquake (Level 3) is newly defined, and their seismic design criterion are proposed.
With the development of internet marketing, logistics bases have been increasing recently. Under the influence of the 2011 Tohoku Earthquake, base-isolated steel warehouses are on the increase. As the roofs of most warehouses are made of steel plates and with small loads, the rooftops of most warehouses are light. However, the current story shear coefficient distributions of base-isolated buildings are based on the buildings with a homogeneous mass and stiffness. So, this report shows a verification on the story shear coefficient distributions of base-isolated steel warehouses with an inhomogeneous mass and stiffness.
In estimating the wind-induced responses through time-history analysis based on stationary random process, its responsive value must be dealt with numerous numbers of statistics. However, the designing value is often determined from the small number of samples because of limited time and expense in practice. So, it is important and necessary to estimate dispersion of wind response from small number of samples. In this paper, the influence on wind responses of elastoplastic multi-degree of freedom system model due to the difference in the number of samples used as an ensemble average is elucidated.
The Pacific coast of Tohoku Earthquake in 2011 caused destructive damages by not only itself but also tsunami in the coastal area. In this report, we propose evaluation techniques of structural safety of seismically isolated buildings (SIBs) against tsunami load by focusing on a characteristic of an effect of shear force on SIBs. In addition, we analyze story shear force and shear deformation angle on superstructure and structural behavior of laminated rubber bearings when tsunami load or seismic load is working on SIBs for the purpose of exhibiting applicability of the evaluation criteria.
This paper propose a method to estimate overall building responses during an earthquake using acceleration records from limited seismographs those have input-output relationship. The design model of the building is updated to a model closer to reality by applying Bayes’ theorem, to estimate building responses. The method is applied to seismic response analysis results, which shows extremely precise evaluation ability of the method. To evaluate the accuracy of the method, the method was applied to using large shaking table test where building responses of each layer have been recorded. The response estimation results substantially match the actual observations.
In order to evaluate the bearing capacity of steel piles with continuous helical wing fixed around a pipe shaft, full-scale loading tests were conducted on eight piles in sand & clay deposits. The results have shown that the shaft resistance of the continuous helix piles is significantly larger than that of the driven piles and/or the steel piles with a helical plate attached near the tip and it can be determined with the frictional resistance of soil acting along the cylindrical surface of pile having a diameter of Dw (Dw = continuous helical wing diameter).
An evaluation of the seismic performance of pile foundations by the structure experiment for the ensuring of safety and post-earthquake functionality is important. It is desirable to perform the structure experiments to estimate characteristics of the piles on a condition similar to the actual situation. In this study, the surveys on the actual applicable conditions of concrete piles in seismic design against severe earthquakes and the analyses of those data were carried out.
In this paper, inversed coefficients of subgrade reaction (kh) estimated from past horizontal load test data of single piles with wide range diameter in cohesive soil deposit are studied. As the result, reference kh (kh0) calculated with unconfined compression strength has good correspondence with inversed kh0. The inversed kh0 obtained from the values at y/B = 0.01 (y: pile displacement, B: pile diameter) has good correspondence with that obtained from the values at y = 1cm. Further, the variation of the calculated kh0 based on y/B = 0.01 and B-1/2 or B-3/4 is smaller than that based on the method of the AIJ recommendations.
In our previous study, we proposed the joint-making method for constructing temporary emergency buildings in areas affected by hazards using gaffer tape and rope to construct bamboo structure and discussed the allowable strength of joints. However, we have not examined the precise restoring force properties of joints. In this study, we first construct a restoring force model for a single joint based on experimental results. Next, we apply the model to a simple full-scale truss and conduct numerical analysis. Finally, we discuss the validity of the model by comparing the numerical results with the experimental results on the actual truss.
This paper presents the results of lateral shear performances and hysteresis characteristics of the mud walls that have been made by three plasterers in Kyoto. The specifications of the mud walls and the mixing preparation of materials are different in those ones, but the material of mud before mixing is the same. In the results of the test, envelope curves were almost the same until maximum strength. The coefficient of the effective wall length is about 1.8. In this tests, strength of the wall was reduced after tearing of mud wall.
In this paper, a new moment resisting joint for timber houses with narrow widespan is proposed. This joint is formed by putting one beam between two columns and these members are grooved with sawtooth-shape section in their panel zone area. To grasp the structural characteristics of this system, double shear experiments and bending ones were carried out. To compare the results with the ones of non-groove joints, it was found that this system demonstrated high rotation rigidity by meshing grooves each other in early stage. Ultimately share bolts worked in cooperation with the grooves complementarily and they realized high strength.
The shear stiffness of steel-timber connections using high-strength bolt and steel pipes in direction perpendicular to grain was analytically and experimentally evaluated. The initial shear stiffness obtained by splitting tests of the connections by the authors was 3-4 times greater than embedment stiffness evaluated by using existing equations. Finite element analyses were conducted and it was found that the difference maybe generated by the embedment of washer and friction between the steel plate and timber.
This paper describes structural features in frames in the direction of a frontage of kyo-machiya which have three rooms in a line. In frames which have a column called ‘daikoku hashira’ or ‘syoukoku hashira’, about 50 percent of the houses have multi-story shear walls in their rooms. In frames of front or back of the houses, about 50 percent of the houses have a ‘through column’ excepting ‘through columns’ on both sides which pass straight through two stories. In addition, these frames have many openings and some houses have no walls at the first story in these frames.
Mimitsu in Miyazaki prefecture is selected to grasp the seismic performance of traditional wooden houses. Seismic performance of 8 houses is evaluated based on microtremor measurements and structural investigation. As results, there are 2 types of traditional houses. One is the type with rooms in a line, and the other is with rooms in 2 lines. The traditional houses have skip floor structure, and the vibration mode is complicated. Yield base shear coefficients of houses with rooms in 2 lines are lower than those of houses with rooms in a line.
This paper reports the results of evaluation on seismic performance of traditional wooden houses in Seki, where damage caused by future earthquakes is concerned, based on structural investigation. Our conclusions are as follows. a) There are many houses that have complex plan and structure. b) Yield base shear coefficients in ridge direction is small. Moreover, we find houses that falls below the value of 0.1 because the weights of house are heavy and there is no wall adequately in the first floor. c) We confirm termite damages at a rate of around 30 % of the target houses.
The properties of old concrete are important factors in the seismic evaluations of existing RC buildings. It is investigated that those properties of concrete in existing buildings are affected by deteriorations over long time periods, uncertainty of construction and several other important factors. 31 concrete cylinders were obtained from the structural members of an RC gymnasium planed for demolition. The mechanical properties of concrete are mainly discussed. The carbonation tests and the componential tests are also performed for the material properties.
This paper proposes grade beams made of H-shaped steel covered with plain concrete (SC) for superstructure made of steel. The SC grade beams have three merits over conventional reinforced concrete beams: improved construction accuracy, easier connection between grade beam and steel superstructure, and shorter construction period. Full-scale tests of SC and bare steel beams were conducted with different sections and spans. The initial stiffnesses of SC beams were two to three times of those of bare steel beam. The strengths of SC beams were three to seven times of those of bare steel beam, because torsional deformations were prevented.
On the retrofit of existing sub-standard RC building with buckling restrained braces (BRBs), the insulation of elastic steel frame around BRBs is effective for restraining the residual deformation and the distribution of damage to whole structure. On this paper, the non-linear hysteresis of steel frame member including the composite effect observed during the previous cyclic loading test is modelled to investigate its influence on the over-all structural response. Also, when the composite effect is unevenly distributed on each retrofit member, the worst distribution case of the composite effect is searched with genetic algorithm on the aspect of seismic performance is investigated.
When we used a conventional method about the “specific ceiling” because it is necessary to secure a performance established in Ministry of Land, Infrastructure and Transport technical standard, it was necessary to attach many braces. Therefore the conventional method was very difficult to plan the building equipment. The coauthor developed the new earthquake-resistant technique of the “specific ceiling” using a light weight steel frame established in Japanese Industrial Standards. It is the system which we named “Linear brace” and can secure very high rigidity and strength. It was recognized that the earthquake-resistant performance of the ceiling was largely improved.
The purpose of this research is to propose the intermediate-scale method of free-standing box test that could evaluate the fire safety performance of sandwich panel systems. ISO13784-1 (free-standing room corner test) and three types of free-standing box tests were performed. It was found that there is some correlation between ISO13784-1 and free-standing box test with respect to reaching flashover.
This study surveyed evacuees from Miyagi, Japan after the Great East Japan Earthquake to elucidate their living environments and intentions. Comparing living environments among various types of temporary housing, their levels of satisfaction differed. Over half of the residents of prefab housing were the elderly and economically vulnerable people, who were highly dissatisfied with their living situations. Among them were households living apart from their families due to space limitations. However, homeowners who wished to rebuild their damaged houses tended to be younger and have higher annual incomes than those who preferred to keep living in public housing for evacuees.
The car tire and the rubber ball are standard impact sources to measuring floor impact sound. Both impact sources have same impact time, but different frequency characteristics. Purpose of this paper is to examine the correlation of two impact sources by comparing with frequencies in each floor impact sounds, and clarify the compatibility of two impact sources. We found that both floor impact sounds are correlated with octave frequency of 63Hz and under, uncorrelated with 125Hz and over. Therefore, we can make equivalent evaluation of heavy weight floor impact sound at 63Hz band.
Sub committee on measurement and analysis of environmental vibration is accumulating building vibrations. The vibration caused by conventional railway in a two-story wooden apartment house has been measured since 2003. In previous paper show damping ratio of wooden house is high and vibration frequency caused by conventional railway is high. It is outside the scope of “Guidelines for the evaluation of habitability to building vibration”. In this paper considering to extend of application the guideline or to evaluate other methods with relation between the various vibration quantification and sensation.
This paper proposes a prediction method of floor vibration reduction by control system using film type piezo-electric device. The prediction method is based on the FEM. Detailed FEM models of piezo-electric device and floor structure can express the quite minute behavior of them, and vibration reduction can be calculated by the results of the FEM. Moreover, the validity of the prediction method was confirmed by an observation result of trial designing of a scaled floor.
Demand of thermal insulation renovation with an emphasis on cost is I considered to increase in the future. So, we went in the development of highly insulated wooden sash of thermal transmittance 0.5[W/m2·K]. In this study, we compare production when CO2 emissions, the CO2 emission reduction effect when attached to the actual housing for the model with three glass that reduce the number of models and the glass using four glass is, it is an object of promotion of low-carbon society by opening repair.
If an earthquake occurs, damage to sprinkler piping, thus need to be kept in working order, can lead to secondary damage such as water leaks, making it difficult for the building to be used. Therefore, a refurbishment plan need understanding the seismic performance around the sprinkler head and arm-over drop piping of sprinkler. So, this study what shaking table tests about flexible piping. It grasped vibration characteristic from vibration, and the effectiveness of the arm-over drop piping in shaking table tests, response value of the piping for structural frame with vibration characteristics, the basic date for the numerical analysis.
PMV control system was applied for a ceiling radiation cooling/heating system utilizing groundwater as heat source/sink. One of our main aims in studying a groundwater-based radiant air-conditioning system is to develop an equipment system and control method that make it possible to maintain a comfortable indoor thermal environment by circulating cold water cooled by heat exchange with groundwater without the need to use a heat pump in summer. This paper describes the differences of the indoor thermal environment and system energy consumption between ceiling radiation and floor radiation under PMV control in summer cooling case.
A questionnaire survey on building characteristics, energy consumption and energy saving behavior of occupants in both a rural area and an urban area of Japan was conducted in 2008 and 2009. The purpose of this survey is to grasp the characteristics of energy consumption in residential buildings located in a rural area from the viewpoint of home energy savings. This paper describes 1)housing characteristics of residential building such as equipments for a space heating and hot water, occupant’s behavior for space heating and occupant’s environmental consciousness, 2)annual home energy consumption in each area, and 3)analyzed results on relationship between regional characteristics and residential factors by multivariate analysis method.
The direction of the light which transmits a window is reversed in daytime and nighttime. It is considered that windows at night have the function to deliver internal various information to the outside. This research examined the psychological effects which window lights have on external pedestrians and neighboring residents. The experiment showed that the warm color window lights located in the first floor whose inside can be seen tended to improve various effects to the pedestrians who are in the street. The interaction was confirmed only by the position of the window, and the color of light. Evaluations of suppression of dumping garbage, etc. rose remarkably with the window of warm color light on the first floor.
The purpose of this paper is to focus on insulation of wooden Japanese house in 1950s, and to make clear how architects have adopted insulation to their designs. Studies on following subjects were made, through researching detailed section drawings and articles in Japanese architectural journals in 1950s; 1) Ratios of insulated elements and insulation materials, 2) Details and heat performance of insulated elements, 3) Architects’ remarks on insulation, 4) Architects who were highly conscious of insulation.
The purpose of this study is to figure out the organizational framework and operational method of local constructors’ alliances, which are formed after the Great East Japan Earthquake, for the construction of wooden public housing. This production system is based on contracts with local governments, which refer governmental procurement method, to purchase housing constructed by the alliances. This research categorized these alliances according to the characteristics of their key stakeholders, which are forestry companies, local constructors, and outside supporters. All alliances should afford the initial cost of construction by using their own resources or supports from outside.
As hundreds of residential facilities for the elderly are built in China every year, the necessity of providing private bedrooms for Chinese seniors remains controversial. This study investigated facility residents’ preferences for bedroom types through a questionnaire survey in Shanghai. The results suggested greatly separated preferences for private bedrooms and double bedrooms, which were significantly related to respondents’ gender, former occupation and marital status. Moreover, elders’ opinions on bedroom sharing indicated distinct values regarding collectivism and individualism. The results are expected to further the understanding of Chinese elders’ concerns about spatial privacy, thus benefit the architectural planning of relevant facilities.
“Immersive Virtual Environment (IVE)” could be useful for the field of architecture. This paper focused on the factors for a grasp of an accurate distance in the IVE. A total of 10 normal sight subjects were individually asked to match up their image distances to the standard distances, which were between the sphere and the subject in the IVE. We conclude that the image distances are close to the standard distances, when “3m” is the standard distance or the subject attention to the distance that is between the sphere and a floor.
The thatched house is ecological and beautiful architecture. However, for being easy to burn, most thatched houses disappeared. Therefore, we investigated the conservation reality of thatched houses constructed by Geishu style in Kamo area. The result is as follows. There were 188 thatched houses in 2002, but decreased to 105 houses now. In addition, we grasped the house placement and inhabitants’ evaluation. There are many thatched houses in the district where a professional of thatched house lives in. Then some houses will be conserved in future. However, these houses may disappear because a professional became old.
This study aims to clarify reality of projects, effectiveness of base places, and problems through study of three projects for dual-habitation without own a home. Findings are as follows; 1) A host of place running dual-habitation business by meeting a particular need. 2) Base place have the effect of reducing the economic burden, cutting down on a burden of maintenance, and showing the variety of dual-habitation styles. 3) A host of place acts as a mediator and creates a weakly link between guests and local residents. 4) It is effective to incorporate regular usage business with temporary usage business.
The purpose of this paper is to determine the optimum location of the fire station based on the actual data of fire and ambulance in Utsunomiya City. The result of the analysis, we found that the large population area is in high demand of emergency transportation and the ambulance service can’t handle a plurality of demands at the same time in such areas. The result of the optimal location analysis indicated that they can correspond to both demands by locating 8 or more fire stations. It showed the guidance for the locational planning of the fire station.
This research aims to compare the conservation situation and the features of existing walled cities in Europe and China. Following are the results of 48 walled cities selected for this study. After considering the extended form of the city wall and the urban form of each walled city, cluster analysis was carried out for each walled city using city wall space, urban scale, and urban form as variables. The 48 walled cities were typified into 4 groups and finally, suggestions for the future conservation of each group were given based on the features of them.
This study purposes to obtain the knowledge about “Closed schools utilization system in Miyoshi city, Tokushima prefecture, Japan”. The main success factors of this utilization system found out in this study are as follows. 1) Assignment of designated staff. 2) Constructing the cross-functional system between local government organizations. 3) Setting of utilization guideline. 4) Free loan of facilities. 5) Setting of utilization standard based on the actual status. 6) Establishment of business scheme where local government, business utilization entity, & local residents are coordinated. 7) Proactive promotion activity, and so on.
The purpose of this study is to document refugees’ attitudes using a questionnaire survey and estimate the condition of shelters during the start-up period. The results of this survey provides estimates of the number of evacuees, the local councils’ preparations, and refugees’ attitude. Prominent issues were categorized into four types: 1) Shelters having a high risk of overflow shortly after the earthquake 2) Shelters in areas having a high proportion of house collapses and fires and inactive shelter-operating councils 3) Shelters with inactive shelter-operating councils and poorly informed inhabitants 4) Shelters that have to consider numerous stranded commuters
This project challenged to stress the characteristic of natural environment, such as the Tama River, abundant green and strong wind peculiar to the location at the Futakotamagawa Rise's pedestrian passage. 2,000 swinging sheets reflecting ambient lights were attached to the trees or the stairs. The road surface was illuminated with the blue lights which remind the Tama River, and the ripple of water was projected on the bridges. As a result of the implementation, sensational evaluations of natural environment have been improved. In addition, where the visitors have conducted a workshop to install lights, emotional attachment to the place has increased.
We developed the landscape resource map for the discovery and sharing of landscape resources by local residents and reported process and the result of evaluation by local residents. Landscape resource map is but also basically be applied in other districts, there are points to keep in mind. First, in the case of new town or uniform residential area, it is necessary to devise an analysis of landscape elements. Second, although majority of students in Shiroko Machidukuri course are the elderly of more than 60 generations, it is desirable that the various generations participate in development of landscape resource map.