According to the investigation of research thesis, this paper describes the cement effectiveness factor of fly ash of concrete using fly ash cement (type-B). As the result, the main conclusions are as follows. The cement effectiveness factor of fly ash tends to increase as the unit of portland cement increases. The cement effectiveness factor (K) of fly ash are 0.7～0.9 in case of hydration heat, 0.25～0.5 in case of strength of 28 days, 0.6～0.9 in case of strength of 91 days, 0.4～0.55 in case of carbonation with outdoor exposure, 1.35～1.6 in case of salt penetration.
200 MPa class ultra high strength concrete is easy about brittle fracture and explodes on fire. As their countermeasures, the steel fibers are used to suppress brittle fracture and polypropylene short fibers are used to suppress the explosion in fire. However, the previous studies have reported that the strength of concrete is affected by steel fibers. And the fluidity of concrete is reduced by polypropylene short fibers. In this report, the influence of steel fibers, polypropylene short fibers and their combination on the fresh and mechanical properties of 200 MPa class concrete is introduced.
The properties of old concrete are important factors in the seismic evaluations of these buildings. For this study, concrete pieces were obtained from an existing RC building constructed at 1969. This paper mainly discussed the mechanical properties, carbonation rate and mix properties of the concrete. The compressive tests, tensile splitting tests, pull-out tests, componential analysis of concrete, and carbonation tests were performed. In addition, the observed values were compared with the present standard and various estimation equations.
As a selecting method of ceramic masonry units recommended for environmental conditions, a method using its strength and water absorption is shown in JASS7, but the reason of the method is not clear. In this paper, various evaluation methods of the quality of the ceramic masonry units (Burny’s method, JIS R 1250 method, three kinds of freezing-thawing test) and an accelerated chloride deterioration test were carried out, and the results were compared with the method described in JASS7. As a result, the evaluation method described in JASS7 is considered to be appropriate.
The authors focused on blowholes caused by the anticorrosive paint for the groove. The parameters are the assembly method of the backing strip and the presence or absence of the mill scale on the surface where the backing strip and the base metal contact. As a result, many blowholes were generated depending on the assembly method of the backing strip without completely removing the mill scale. By the assembly method of the backing strip from the groove side, the blowholes were reduced to the same extent as the complete removal of the mill scale without removing the mill scale.
This report examines the effect of temperature up to 3 days after casting on the standard curing strength. When cured at low temperature up to 3 days of age, the standard curing strength increases, and when curing at high temperature up to 3 days, the standard curing strength is low. In the high strength concrete, the structure strength correction value will be underestimated if the early curing is in summer temperature. In hot weather concreting for general strength range, if the early curing is in summer temperature, the structure strength correction value will be underestimated by about 3N / mm2.
We conducted a crack survey of floor slabs in distribution warehouses up to 5 years old. As a result, the crack coefficient at 5 years of age was about 70 × 10-6 to 100 × 10-6 on the 2nd and 3rd floors, and about 30 × 10-6 on the 4th floor. The reason why the 4th floor is smaller than the other floors is that it is used less frequently than the other floors and is less affected by external forces such as vehicle running, and the slab is less restrained than the other floors.
This study describes the methodology for measuring the thermal deformation of concrete specimens. Specimens should maintain a saturated state for preventing strain change by moisture content and we conducted strain measurement with temperature changes considering the underwater environment. The strain gauges were waterproofed to protect from moisture. To calibrate the thermal output of the strain gauges, we corrected the strain measured on the specimens by using additional dummy gauges. In addition, to obtain the strain of cement paste itself accurately, the measurement location of the specimen should be considered by the distribution of aggregates and the shape of the specimen.
To verify the measured accuracy of the snow depth on the roof by SfM-based photogrammetry using aerial images, the authors performed aerial photography by UAV and measurement of the roof snow depth for the gymnasium of Hokkaido University of Science. Phantom 4, Phantom 3, and Mavic Pro were used for aerial photography. As a result, it was found that the RMSE of the roof snow depth was 30 to 40 mm. In addition, it was found that it is necessary to secure the number of images that satisfy the conditions of 90% overlap ratio and 60% side overlap ratio.
When a base-isolated building collides with a moat wall, there is a possibility that the building may collide with the moat wall with torsional impact due to the effects of unavoidable eccentricity caused by the performance variation of the seismic isolation devices. However, the effect of torsional impact on building response has been insufficiently studied. This paper reports on the response characteristics and impact force of buildings and moat walls by using analytical models which can evaluate torsional response at each moment.
This paper presents the seismic response characteristics of viscous dampers in extremely small excitation. Real-time on-line tests were conducted using viscous dampers to examine the influence of sliding resistance force on the extremely small excitation. In addition, the damping characteristics of the viscous dampers are compared with a linear model. This paper shows the importance of accurately modeling the characteristics of viscous dampers in the extremely small excitation.
This paper proposes a simple mechanical on-off damper that can change the damping force depending on the response displacement and response velocity. The on-off damper reduces the damage to seismic-isolated structures that undergo excessive deformation during huge earthquakes, without lowering the performance of the seismic-isolation system during design earthquakes. A numerical analysis method for base-isolated structures in which the isolation layer is equipped with our on-off damper, and also considers collisions with stoppers, is expatiated. A shaking table experiment was conducted, and the results were compared with the numerical analyses. The test results agree approximately with the numerical analysis results.
There are only few available studies about wind response of base-isolated high-rise buildings. Conventional design wisdom for wind response is to consider peak responses. However, according to observed wind speed and acceleration of a base-isolated high-rise building, the acceleration peak factor is larger than the expected design value. As such, the authors carry out analysis considering two typhoon records for wind speed and acceleration stability. Results show unstable characteristics of wind speed and acceleration, and in certain time duration, unstable characteristics even for 1 minute.
The placement and number of passive dampers employed in building greatly affect the response reduction, thus, must be considered in designing. In the previous study considering only one damper layout plan and constant damper ductility demand, the effective damper deformation ratio of optimal shear coefficient to be the median value was confirmed. In this paper, several damper layout plans and different damper ductility are considered, and the effective damper deformation ratio of optimal shear coefficient and of maximum equivalent damping ratio in order to clarify the relationship between the effective damper deformation ratio and damper ductility demand are compared.
In the current wind-resistant design code, buildings are designed to remain elastic. As they become taller, however, wind force on them tends to increase drastically thereby making them more susceptible to plastic deformation. It is, therefore, vital to evaluate the elasto-plastic response of high-rise buildings to wind forces. As such, this paper proposes an elasto-plastic wind-induced multi-degree-of-freedom response prediction method for a passively controlled high-rise building with hysteretic dampers, and examines the accuracy of the proposed method.
Axial force of CFT column and steel column embedded into cast-in-place concrete pile were measured in top-down construction method. In addition, measurement results were accurately simulated by FEM analysis. Axial force transfer mechanism from CFT column to pile is analyzed according to field measurement and FEM analysis results. At the pile head, axial force of concrete transferred from steel column is increasing and becomes stable due to slipping between steel column and concrete. Besides, it was found that shear strength of stud connectors at the pile head are 60% of design shear strength.
This paper describes with experimental study on in-situ test and thermal stress analysis of cast-in-place pile using high-strength concrete. This investigation led to the following conclusions. 1) a belled pile with a maximum width of 6.7m was carried out, and no cracks occurred in the pile body. 2) From the results of the thermal stress analysis, temperature difference between center and outer circumference of the pile can be suppressed to be smaller in the ground than in the air, because of the heat preservation effect. For this reason, it was found that thermal cracking is unlikely to occur in the ground.
A sloping ceiling produces a response in the direction out of the ceiling plate surface only with horizontal force, so the mechanical properties are more complicated than with a horizontal ceiling, and quantitative grasping is difficult. Knowledge and experimental results are also limited, therefore, proper seismic design methods for sloping ceilings are not well established. The authors quantitatively grasped the mechanical characteristics of the sloping ceiling by adopting a ceiling method, that can simplify the horizontal force transmission path by using a diagonal member that directly connects the ceiling plate and the floor slab of the building.
In this study, I presented the experimental results of four 1P mud walls, which two damage levels of the walls, the experienced maximum deformation angle and the accumulated one, are known. The strength characteristics after the restoration were examined, based on the results of the cyclic loading test of these walls. In the restorations, I took care to ensure that there was no gap between the practice and the research. The experimental formulas for the stiffness reduction factor and the strength reduction factor after restoration compared to before restoration were shown by comparing the envelopes of the restoring force characteristics.
We reported the results of a structural survey of one traditional townhouse in Furumachi, Kumamoto City, which was not largely damaged by the 2016 Kumamoto Earthquake. In addition, considering the effect of continuous columns by simple models, we performed the time history response analysis with the seismic observation, and examined the difference in the maximum response drift angle with and without consideration of continuous columns. From the above, it can be inferred that one of the reasons why the house did not collapse in the 2016 Kumamoto earthquake was that the continuous columns worked as a load bearing element.
We developed a timber semi-rigid frame construction system composed with coupled glulam members jointed by screws with steel side plate and high-tensile bolts. Firstly in this paper, we designed the interior and exterior beam to column joints and the frames consisting of the joints of beam end joint precedent yielding type. Secondly, we conducted the bending tests for the frames to confirm the characteristics of the failure behaviors and the estimability of their mechanical behaviors from single screwed joint properties.
Seismic diagnosis has been carried out to improve the seismic safety of residential houses including those of traditional wooden houses by Kyoto municipal government. In this paper, we compiled the seismic evaluation data of 882 traditional wooden houses. Then, we statistically analyzed the structural characteristics indices of houses such as equivalent natural period and equivalent damping coefficient. We also analyzed the seismic performance indices such as the base shear coefficient. Finally, a seismic evaluation method of traditional wooden houses is also analyzed.
The purpose of this paper is to verify the accuracy of a density estimation method for columns of traditional timber buildings and to improve applicability of the method to actual buildings in repair site. In this paper, a specimen with hanging walls is used and the density of column is estimated from the changes of its fundamental frequency before and after adding weight. In the proposed method, the accuracy of density estimation increases as added weight gets heavier. Microphone measurement can estimate the density as well as accelerometer measurement although the accuracy is slightly lower.
Column-to-nuki connections are important to evaluate the seismic performance of traditional timber shrines and temples. These connections include several joint types, one of which is the oblique scarf joint. However, few previous studies have examined the column-to-nuki connections of the oblique scarf joint and no design equations exist for them. Thus, this study aims to evaluate the structural performance of column-to-nuki connections in traditional timber shrines and temples based on the full-scale tests. It is shown that the theoretical value of 50 % continuous nuki can safely evaluate the experimental value of the oblique scarf joint.
Self-tapping screws are often used in the joints of wooden buildings in Japan. It is useful to use the EYT formula to estimate the shear strength of screw connections. To estimate the shear strength of screw connections, it is necessary to apply the embedding strength to EYT equation, but there is little knowledge on the embedding strength of timber by screws. In this paper, embedding test methods of timber by screws were compared, and then was conducted. Furthermore, the evaluation method of embedding strength based on the results of the test was proposed.
In order to develop precast concrete pile which has compressive ductility, static uniaxial compressive test was conducted using precast concrete pile specimens. Some of the specimens are precast concrete solid pile with unbonded steel pipe. In the result, precast concrete solid pile with unbonded steel pipe had ductile behavior, ultimate strain of specimens was more than 4.0 %. Furthermore, compressive capacities of the specimens are evaluated using existing formulae. In the result, the existing formulae underestimated the compressive capacities of test results.
During an earthquake, the members surrounding the damper are subjected to combined bending moment and axial force produced cyclically by the actions of the damper and frame, respectively. Damper force and damper deformation have shifted phase, and the latter is in-phase with the frame story drift, which makes phase difference between the bending moment and axial force. In this paper, we propose data analysis method. It will be used to obtain internal bending moments and axial forces of all beams and columns damped frame, they are obtained based on the phase difference of the frame and damper actions.
This paper presents experimental data of material testing of lime plaster joint of some historical brick buildings on the same site. The data of shear strength, tensile strength and compression strength were obtained through the test. The following observations are notable: 1) The lime plaster joint of some buildings which were built at a different time indicates the different capacity; 2) The shear, tensile and compression strength clearly correlate one another. As tensile strength is low, shear strength and compression strength are also low; 3) The relation expressions of tensile strength and shear strength were proposed in this paper.
Masonry walls are widely used as infill in RC buildings even in the countries with high seismicity and affect the seismic performance of buildings. Due to the vulnerability of masonry infill walls to earthquakes, out-of-plane collapse should be considered when their effects on the seismic performance of buildings are discussed. Hence, this study was performed to experimentally investigate the out-of-plane behavior/performance of a typical brick masonry infill wall in Bangladesh and to propose a simplified analytical model to estimate the out-of-plane resistance. Findings from this study will contribute to the performance evaluation of RC buildings with masonry infill walls.
This paper proposes new joints between column bases of steel superstructure and Steel Concrete (SC) grade beams that make moment transfer possible with large stiffness. Three types of joints are devised: (a) reinforcing the H-shaped steel in the SC grade beam by stiffeners, (b) reinforcing the upper flange with T-shaped steel, and (c) connecting the base plate and the bottom flange with screw bars. Full-scale tests were conducted using simply supported SC beams with cantilever columns. The stiffnesses of the proposed column bases were 3 to 4 times that of the conventional exposed-type column base.
It takes time to carry out the post-earthquake quick inspection of many damaged buildings after large earthquakes. As image classification method of damage level after earthquake, deep learning with convolutional neural network is applied to reinforced concrete columns. We achieve a classification accuracy of 77% by AlexNet and 80% by VGG16 in case of transfer learning. To show the reason of classification, Grad-cam is utilized.
Flexible wooden boards with new sound absorption characteristics have been developed to improve the indoor acoustic environment of buildings. These sound absorption characteristics, achieved with a Helmholtz resonator, vary depending on the cross-sectional shape and surface shape of the boards. Also, the sound absorption performance is confirmed in an actual building. The results will lead to the development of sound-absorbing wooden as interior materials and also promote wooden interiors of public buildings.
This paper describes the results of CFD analysis and measurements regarding indoor climate in winter and summer in a wooden office with a hyperbolic paraboloid roof. In winter, the air from the underfloor space heating was circulated whole the room by the temperature difference ventilation. In summer, the first floor was cooler than the second floor by cool radiation from the floor surface by cold storage in the underfloor space. Furthermore, the average temperature of the room from winter to summer was 25°C. The staff have cultivated their cognitive temperature scale for comfortable sensation in winter and summer, respectively.
The last year our report describes the results of thermal environment settings about a cool spot installation in the radiation cooling/heating office through the subject examination of fitness and going-out action. In this research, we attached fine mist spraying area to cool spot. And the effectiveness evaluation was carried out considering “restoring time” from after-exercise sensation to original sensation. The feature of this research is that the attachment of the fine mist spraying area can reduce the number of the restoring time regardless of thermal environment settings of cool spots.
Thermal storage air-conditioning system is a highly efficient technology for peak load reduction and load leveling of electric power. Therefore, the thermal storage systems have been widely applied since 1960s mainly to office buildings. Currently, many of these buildings are reached the time of renovation. Dealing with existing building renovations, we have to take actual building usage into consideration in remodeling plan and design appropriately from the point of further reduction of carbon dioxide emission or energy saving. In this paper, we report an investigation study on actual energy efficiency renovation with a water thermal storage system.
District heating and cooling is one of the important ways to promote efficient energy use. In the district heating and cooling area, cooperative operation between the supply side and the demand side and advanced control are indispensable to further improve the energy use efficiency. In this study, we conducted a questionnaire survey of DHC operators nationwide to investigate the actual status of supply and return water temperature. This study describes the results.
We conducted an outdoor experiment using mannequins wearing different colored clothes to clarify the effect on surface temperatures. Experimental results showed temperatures of dark-colored clothes were higher than that of light-colored clothes by 10℃ during the daytime. Referring to ISO 7243, we also examine the heat balance equation of human body from the viewpoint of metabolic heat production caused by changing colors of clothes. Temperature differences of clothing colors in WBGT were very large, up to 5℃, and wearing clothes of light colors are strongly recommended from the view point of the prevention of heat stroke.
The purpose of this paper is to examine the results of the “Residential environment check and improvement program” in the Edamitsu-ikku district. Launched in 2006, the program consists of neighborhood associations, regional councils and laboratories that exchange information by surrounding maps and records. As a result of continuous program for more than 10 years, improvement activities have been widely carried out by residents in each neighborhood association. In addition, in 2016, the Administrative Committee was started to promote improvements in areas that had long been problematic. Since then, improvements have been made in public roads, houses and vacant lots.
This research focuses on public housing management in Muroran city and clarify how the management status affects evaluation of living environment by residents. The results of this study are as follows: 1) there is 15% of public housing without manager, 2) evaluation of living environment is related to the management status, 3) intent to move from public housing is related to the management status, too.
Through analysing the history of the transition of the Nakagin Capsule Tower design by Kisyo Kurokawa, this paper gives a new understanding of the transformation of housing for one-person households and the challenges that so-called ‘one-room mansions’ in Japan may face in the future. The transition is explained from three features; utilisation, ownership and management. The relationship between the three features gradually separated, which eventually led to the decay of the building. Even after the owners’ association started to function, technical and legal challenges and the difficulties in settling the interests of the owners hinder taking effective measurements.
This study defines cases of living base places formed on the moving process to the villa area in Hara Village, Nagano Prefecture. The followings are the main findings. In addition to single-track migration in which “only one main base”, there are patterns with “secondary bases” and “temporary housings”. Staying in the area before migration helps to imagine the lifestyle after migration and to prepare the house and jobs. Transitional housing styles like rental houses are important for people who want to move to a new location.
Depending on the disaster situation, it is necessary to prepare in advance a plan that considers the use of the corridor space for medical aid stations in consideration of the possibility that areas originally intended for such purposes may not be useable. We conducted a survey using a model in order to gain knowledge about the facility design that makes it easy to construct a medical aid station in the corridor space of a hospital. The survey was aimed at clarifying the characteristics of the set-up contents and problems during set up when accepting casualties in planned corridor space.
This study analyzed the impact of the physical environment of a hospital on cognitive abilities. Using random forests, we analyzed the effects of the number of room changes and room type (private rooms or multi-bed rooms) on cognitive ability. The results showed that the physical environment (number of room changes and room type) was the fifth least important factor in assessing the degree of influence.
In the past, Japanese temporary housing was supposed to be prefabricated light-weight steel building because of the production speed and amount in emergency. However, since the Great East Japan Earthquake in 2011, timber temporary housings have been provided. For 2017 Northern Kyushu Heavy Rain, Fukuoka prefecture constructed 107 timber temporary housings in Asakura city and Toho village. In three of four sites, timber community houses were also built. Our laboratory at Kyushu University cooperated with Fukuoka prefecture to design these community houses. We describe these details of the design and the process of construction in this report.
The “Wintering plan”, which enables short-term institutionalization for a few months, is a way to live in a home and an institution in combination. This paper aims to clarify how the “Wintering plan” contributes to the smooth relocation, and extract the effectiveness and the issues of it. As the findings, it became clear that the wintering plan functions as a base for returning home from hospital, a long-term trial stay, and a safety net for those who find it difficult to live at home and securing stable vacancies will be a key issue for the continuation of the initiative.
This case report was conducted in an acute care unit with a distinctive plan to examined the relationships between: 1) amount of nurses’ activity and nurses’ burden-feeling, and 2) plan characteristics and nursing burden. The survey consisted of a questionnaire and three-day-activity survey using a general pedometer. Results showed that the amount of activity in the nursing hall type tended to be lower than that in the middle corridor type. Furthermore, no clear relationship was found between amount of nurses’ activity and the nurses’ burden-feeling. These results suggest that nurses’ burden-feeling is an independent indicator.
In the case of emergency that requires all the occupants to evacuate from a high-rise building, a method of “phased evacuation” is said to be effective for avoiding congestion in the staircase. However, some occupants will feel anxiety because they are requested to stay there until the other occupants in different floors finish evacuating. This study examines how giving information of phased evacuation influence mental state of the occupants. As a result, disseminating the scheme of phased evacuation and giving detailed information to whole the building decrease anxiety while waiting time, and lead to evacuation as planned.
The main halls of temples throughout Japan have undergone a variety of changes in the times through history, and analysis of the changes in the form of their foundations by region and by era of completion chowed that there was a significant change in the foundations of main halls when comparing pre-war and post-war periods. Furthermore, kamebara foundations were expected to be used for long periods.
The purpose of this paper is to examine a house reconstruction system by local builders from a large-scale tsunami disaster. Through the activity of the house reconstruction in Rikuzentakata-city, following knowledges were provided: (1) In early stage of reconstruction, it is efficient to set up a system in a logistical support place. (2) For the development stage, it is better to organize by resident’s association with expert support in order to sustain the community. (3) In spread period, it is effective to organize by the construction industry association in order to deal with specialized issues.
The conservation and revitalization design of Modern Architecture in NANZAN UNIVERSITY is considered based on the design concept of Antonin Raymond and the authenticity of the original buildings. It is also important to take into consideration the basic principles as follows; minimum intervention, harmonization and distinction of old and new design, reversibility to original condition. The most difficult task of Modern Architecture is how to keep the surface of exposed concrete finish and how to design replaced interior space including new machines and lightings. This report verifies the design principle and process for utilization of 20th-Century Architecture as Living Heritage.