In this experimental study, we focus on the Ready-mixed concrete factory using reclaimed aggregate for concrete as building materials. In some Ready-mixed concrete factories, we mixed concrete using reclaimed aggregate, and tested fresh concrete and physical properties. The results show the following points: (1) concrete of using reclaimed aggregate until 20% is same as concrete using original aggregate in testing lab. and site plant (2) a reclaimed coarse aggregate kept for 1 month after collection can use ready-mixed concrete (3) a reclaimed coarse aggregate can be applied to strength class 45 in JIS A 5308.
In order to clarify the influence of corrosion of hot-dip galvanized steel on the structural performance for R/C beam, after corrosion promotion by the galvanostatic corrosion test was carried out, pull-out test for simple specimen and structural loading test for R/C beam were conducted. As a result, it was found that when the normal state, adhesion performance similar to that of the ordinary steel, when the corrosion occurred, the adhesion performance was improved. However, there is a possibility of cracking of the concrete due to corrosion of the plating layer, and in this case, the proof stress decreases.
In order to predict the tensile stress generated by drying-shrinkage, the influence of member thickness, ranging from 50 to 400 mm, on the drying-shrinkage was experimentally investigated on a set of specimens for 19 years. The effective thickness of concrete members was obtained by using diverse concretes of different drying-shrinkage rates, which depended on the mix proportions of concrete, such as unit water content, use of chemical admixture, and type of aggregate used, etc. As a result, it was found that, within each concrete type, the difference in the amount of shrinkage between members of different thicknesses and causing generation of tensile stresses depended on the drying-shrinkage rate and showed a decreasing tendency over time. Furthermore, even when the drying-shrinkage rates were different, the ratio of the drying-shrinkage strain by member thickness hardly changed. These observed tendencies were predicted relatively well using the corrected Rush’s ks value.
Analysis of climate characteristics and appearance research show that frost damage in Kyushu differs from that in cold regions. Conventional methods for calculating the risk of frost damage cannot be applied to warm Kyushu. It is confirmed that the number of freeze-thaw days is effective in evaluating the risk of frost damage by comparing it with the distribution of structures that had caused frost damage. By using climate mesh, Kyushu version frost damage risk map is created.
In the present study, the fundamental property related to thermal crack resistances of a high-strength concrete (BBFA) using blast furnace cement type B mixed with fly ash and heat control type expansive additive was experimentally examined. And the following results were obtained. The adiabatic temperature rise (K) of BBFA is same as or smaller than that of a low heat Portland cement concrete, and there is a possibility of remarkable restraint effects of adiabatic ascents. It is expected that excellent thermal crack resistances were obtained from restraint effects of heating values and autogenous shrinkages by heat control type expansive additive.
Scaffoldings falling-off accidents during demolition works of buildings exterior walls are one of the major issues in labor and public safety in construction. This paper proposes a new strengthening system for scaffoldings, which are inevitably in freestanding condition after the supporting wall have been demolished. Indoor experiment as well as on-site experiment at real demolition site are conducted to verify the strengthening performance of the system against wind. It has been shown that the developed system has sufficient performance at required wind conditions and effectively suppress the displacement of scaffolding so that the system enables to prevent the falling-off accidents of scaffoldings themselves as well as construction workers on the scaffoldings.
In this study, in order to grasp the structural characteristics of RC buildings under consideration of construction by the construction method of remaining some prop by received three-layer, structural specifications of each member were extracted and analyzed from the structural drawing. In this second part of the paper, we focused on buildings of RC slab with small beams continued to the previous paper. As a result, most of the buildings of RC slab with small beams were found to be multi-dwelling houses and were found to be 3 to 15 stories. Moreover, as a result of investigating about these structural characteristics, the standard range of structural specifications was almost the same as the case of RC slab without small beams.
It is well known that moisture condition of concrete is one of the factor that influence on compressive strength of the concrete and velocity of ultrasonic wave through the concrete. However the influence of the moisture condition on the above properties was not discussed sufficiently. In this study, a new method based on moisture condition by using pulsed electromagnetic force acoustic method was investigated to estimate the compressive strength of concrete. As a result, it was found that the linear equation using the acoustic velocity measured by the pulsed electromagnetic force acoustic method and moisture content shows high estimation accuracy.
The number of maintenance work increases as the life span of buildings become longer. This study focuses on calculating the environmental load given by maintenance work of LCCM demonstration house mainly using Life Cycle Assessment(LCA) method for buildings, to compare with the environmental load given by the construction work, and to consider effective measures to reduce the environmental load given by the maintenance work in the future. The environmental load was calculated as 550 kg-CO2, which is 1.4% of the environmental load given by the construction work. 50% of the CO2 emission was given by the manufacture of materials and disposal of waste, and 45% was given by the transportation of workers and materials, so it is considered effective to lessen the CO2 emission by the manufacture, disposal, and transportation to reduce the total environmental load given by the maintenance work.
We clarified the resource circulation through the life cycle for 12 building materials used in non-structural parts (non-structural building materials). In many non-structural building materials, resource circulation was realized at the factory scrap level. In addition, in the intermediate processing company that performed advanced treatment, resource circulation was realized at the dismantling material level for some non-structural building materials. It was suggested that the factors determining the resource circulation of non-structural building materials were the reversibility of constituent materials and composite methods, and a recovery system that recycles waste materials.
We decided to investigate the correlation between the result of the enlarged indication pattern using the penetrant inspection test which is an auxiliary technique for visual inspection and the break position. As a result, except for weld fracture, the following was found about the correlation. (1) In the specimen in which the enlarged instruction pattern appeared, the vicinity of the heat affected zone breaks or the base metal fractures. (2) In the test piece without the enlarged instruction pattern, the base material breaks.
Three typhoons approached Gunkanjima one after another in early July, late July and early October in 2018. Dynamic behaviors of building 30 during three typhoons are evaluated by vibration sensor network using MEMS acceleration sensors. The relationships between global and/or local behaviors of building 30 and wave and/or wind conditions during three typhoons are investigated under the situation that missing data were gradually increasing due to sensor fault in the harsh environment.
During the 2016 Kumamoto Earthquake, wind turbine generator support structures were damaged. Before repair of structures to restart, damage investigation was conducted including damage analysis. The damage mechanism and the characteristics of the damage according to each support structure was explained by the analysis. The analysis showed that the input ground motion level was estimated to be 1.0 time of that at the nearest observation point.
We had already proposed general multi-mass shear models for super high-rise RC buildings using averaged properties of nonlinear parameters. This study investigates fluctuation of seismic response characteristics considering variation of nonlinear parameters, i.e., shear capacity and deformation of tri-linear skeleton points, based on statistical analysis of the 78 models used in the past structural design. Variation of natural period and cracking points has more influences on averaged height-wise distribution of maximum inter-story drift angles than that of yielding points.
Pile groups using steel pipe piles with wings are often constructed to support large-scale buildings. Soil around these piles is known to be loosened during construction. Therefore, to reasonably design pile groups using steel pipe piles with wings, it is necessary to investigate the pile group effects considering loosened soil around pile shafts. We conducted in-situ lateral loading tests on both single pile and two-pile groups with/without wings and discussed the differences in lateral soil resistances of their piles.
Concrete buildings in nuclear power plant (NPP) are often irregularly shaped box frame structures with reinforced concrete (RC) shear walls, according to equipment layout. Generally, these structures are designed in accordance with the NPP seismic design technical provision. However, the applicability of the provision to complex box frame structures has not been realized. In this study, the impact of the RC shear walls with irregularity on the seismic performance of NPP buildings is evaluated using a finite element model (FEM). Moreover, a correction method to apply the provision to those buildings is confirmed by comparing the FEM with the provision.
We verified the damping effect using shear link type of friction dampers on wood frame construction which are generally said to high stiffness. We firstly evaluated the basic performance of the devices by static loading tests, and then we evaluated the damping effect against earthquakes using shaking table tests. Moreover, using time history response analysis, the range of the analysis could follow the shaking table test value. As a result, the performance of the damper was stable in both static and dynamic tests, the analysis value and the experimental value showed high consistency up to the large range of deformation.
Authors develop the two-way flat slab system that is layered CLTs so that the strong axial direction of CLT (Cross Laminated Timber) is orthogonal. GIR (Glued-in rod) joint system is used for joining between CLT. FEM analysis for two-way flat slab using CLT designs is made based on element experiments and the validity of the analysis is compared with keyed beam and several actual measurements of two-way flat slab using CLT in the building.
Long spanned box beams constructed by standard timber of Japanese conventional housing and sheathed with structural panels are useful to construct medium and large scale wooden structures, but creep deformation tend to increase compared to single lumber beams. Therefore it is important to reduce initial deflections. In this study, full-size bending tests of several types of box beams are conducted to evaluate their utility by analyzing initial deflections and fracture behavior.
The external thermal insulation system for wooden houses is one of the popular thermal insulation systems in Hokkaido, Japan. We propose a bearing wall system for wooden frame houses to improve seismic and thermal insulation performance at the same work. The fastener to fix the external thermal insulation system is utilized also to fix structural board more tightly. And the foamed plastic board in the external thermal insulation system to improve thermal performance also improve seismic performance to keep clearance none between structural board and wooden frame. The system provides as almost three times of toughness as normal.
This paper presents the results of micro-tremor measurement of newly-built three-stories wooden pagoda. Five times measurements were conducted during construction and after completion. In each of the measuring result, it was able to confirm the first-order, second-order and third-order modes, respectively. At the last measurement, 1.6Hz of predominant frequency at the first-order mode was obtained. Also, the damping constants were measured by free vibration tests. Finally, the eigenvalue analysis was conducted by the lumped mass system. The ratios of second- and third-order natural frequencies to the first-order frequency obtained by measuring are the same as the analytical results.
Results of analyses on the deflection of slabs demolded early are reported. The analyses take the process of construction and creep of concrete into consideration. The long-term deflection of RC slabs demolded early is 1.6 times that of slabs constructed with the general process. The maximum axial force of the special support in the early demolding process is observed at the time that the supports on the floor two levels above excluding the special support are removed.
In this report, the structural performance of RC beams using modified fly ash slurry (MFAS) removed unburnt carbon by flotation method was clarified by simple beam experiments. The experimental variables were RC beams with MFAS and RC beams without MFAS. As results, 1) the maximum shear strength of the MFAS beam was larger than that of the normal concrete beam, 2) the MFAS beam and the normal concrete beam had almost the same characteristics with respect to residual deformation, strength reduction rate due to repeated loading, and strain degree distribution of tensile main bars.
Unbonded prestressed concrete (hereinafter, UBPC) structure have a high continuous use potential. However, there are few researches on the performance evaluation of structural members, and the low energy absorption ability, the application to main structural members is a little. In this study, we investigate the seismic performance of a frame with a UBPC beam structure and a viscoelastic damper added to the stud shape. Static and dynamic horizontal loading experiments were conducted on the frame specimens. As a result of experiment, the basic mechanical properties were gained. We also examined the energy absorption capacity of the viscoelastic damper.
In recent years, the braces and knee braces have been used for a seismic retrofitting of the steel buildings. Also, the reinforcement of sectional area for steel members has been carried out. So far, the authors have proposed a new friction-type joint device that is required at the time of these reinforcements. The advantage of the proposed joint device is that it does not require bolt-holes and welding in the joint. In this paper, the relaxation tests were carried out in order to confirm the long-term structural performance. As a result, the same results as high-strength bolt were obtained.
We conducted shaking table tests for steel 2-story frame structure in order to clarify seismic performance against earthquake beyond the current seismic design level. In the tests, JMA Kobe (near-field ground motion) and THU (long-duration ground motion) were input. The findings are shown as below. 1) Fracture at beam-ends occurs at a smaller story-drift angle in seismic response of THU than that in seismic response of Kobe. Local buckling of beam flange occurs more remarkably in seismic response of Kobe. 2) The fatigue performance evaluation method of beam-end considering the influence of yield stress can be applied to these tests, and shows good correspondence with past static loading tests. 3) The crack penetration of the beam flange were confirmed when the fatigue damage degree by the Miner’s rule were about 0.7 to 0.9.
This research focuses on deterioration behaviors of the unloading stiffness obtained from loading tests of beam-to-column joints of composite beams and steel beams, and discusses the applicability of numerical analyses. The Ibarra-Medina-Krawinkler model expresses degradations of the stiffness and load capacity based on the hysteresis energy. By giving appropriate parameters, a stiffness deterioration behavior at the positive bending of the experiment was efficiently represented. The difference in hysteresis energy due to the presence or absence of stiffness deterioration reached about 20 % when the value positive bending stiffness dropped to about 80 %.
Ferro-cement is a composite material, which could be easily utilized as a strengthening material for infilled masonry panel from the perspective of workmanship and economy. In this study, the effect of several parameters on shear capacity of Ferro-cement has been compiled from previous experimental test data. A simplified proposal to estimate expected lateral capacity of Ferro-cement lamination is presented.
Long-term weathering test of carbon fiber reinforced plastic (CFRP) plates is ongoing. CFRP is made of PAN type carbon fiber and epoxy resin, and two types of test piece, unidirectional fiber reinforced composite plate and woven fabric reinforced composite plate, are used. Outdoor exposure test began in 1986, after which several series of tests were added. In this report, part of the results of observation and testing of CFRP plates carried out up to 33 years outdoor exposure are arranged and shown.
Hyperacusis, that is, unusual intolerance to ordinary environmental sounds, poses a health risk to a certain number of ordinary people. In particular, developmental disorders tend to have hyperacusis, but their difficulties in daily life are not socially recognized. In this paper, a questionnaire survey on hyperacusis for developmental disorders is carried out, and the actual conditions, what kinds of sound and situation cause the symptom, are figured out.
In this research an evaluation of windows to realize the optimal heat balance according to the regional climatic characteristics and bearings was performed, focusing on the heating load of PVC windows in cold regions. In order to carry out this investigation the Taguchi method for trial calculations was used while studying appendage of windows, the thermal transmittance of windows, the solar heat gain coefficients of windows and the air permeability of windows, and examining their influence on heating load of windows, as well as demonstrating the reduced configuration of heating load of windows.
Appropriate large-eddy simulation (LES) guidelines for pedestrian wind environments are being established by the working group of the Architectural Institute of Japan. We conducted LESs for a flow field around an isolated building to clarify the influence of computational conditions on turbulent statistics. We performed a cross-comparison study by examining both experimental and LES results for various computational conditions such as grid arrangements, subgrid scale models, spatial derivation schemes for convection term, and convergence criterion for a coupling algorithm of flow and pressure fields. Results can be used to provide LES guidelines for predicting the pedestrian wind environment.
Indoor air environment audit in school classrooms with open-space, classrooms with semi-open-space, and traditional classrooms without open-space was conducted seasonally in six elementary schools in Tokyo city area, Japan. During the summer season measurement, CO2 concentrations in the classrooms with open-space tended to be lower than those in the traditional classrooms without open-space, since the open-space type classroom had rather larger air volume. In French school IAQ study, the ICONE (Indice de CONfinement d’air dans les Ecoles) index was used to evaluate air stuffiness during occupied periods. The ICONE index might be useful for estimating the difference on air environmental factors among different classroom types.
In recent years, not only the residence but also the effort of health promotion by improving the social environment including the working and the regional environment has attracted attention. This paper introduces a subjective assessment tool of the work environment, referred to as “CASBEE- Office Health Checklist”. This tool is an assessment tool for workers themselves to evaluate satisfaction for office environment where workers spend a lot of time. By using this tool, people are aware of factors that affect health and intellectual productivity, and it is expected that they can conduct health management strategically, which leads to environmental improvement.
The study focuses on three-story townhouses to clarify their condition of non-residential use. We interviewed four main townhouse developers and researched three typical development sites. The main result are: 1) change from residence to non-residential use is done by each residents, 2) the business types are divided into two-broad area customers oriented and neighborhood customers oriented. 3) the attractiveness for residents are low price, good location, good environment and flexible use. In the other hand, the three-story townhouses varying with time may run into bad condition because of insufficient maintenance and lack of appropriate management as housing area.
The purpose of this paper is to clarify the current situation of housing damage and living space in the initial period toward recovery after the Lombok earthquake which occurred in July and August, 2018. Our field survey was conducted on Bayan village, northern part of Lombok one month after the earthquake. While many houses of masonry structure were damaged, only a few wooden houses were damaged. Especially traditional building types such as bale and berugak were not damaged at all. Berugak are utilized as main space of their living towards recovery. Utilization of natural resources and community bonds have the power for their recovery.
‘Open type preservation and maintenance’ means the situation that maintained soundly by utilizations of the privately-owned houses as tangible cultural property. The purpose of this study is investigating the possibility of it. By the analysis results of interviews to twenty owners, it was cleared as follows. 1) By opening the houses, the connections that substance utilizations are made at inside and outside. 2) The owners place visitors as outside evaluations and motivation of continuous actions. 3) Workshops that develop participants to supporters are effective as utilizing technics for preservations. This shows accelerations of utilizations are one of important preserving measures.
This study aims to report the differences in childcare environment at a child care facility. The focus is on the composition of the supporting spaces and the places for children’s independent activities. The research methods are the questionnaire and the interview survey in child care facilities. By composition of the supporting spaces, it was found the type comprised of one nursery room, corridor and one multipurpose room was most common, but there were the cases where the range of children’s independent activities was small even though the composition of the supporting spaces was diverse.
Our purpose is to clarify the present conditions of medical aid stations (triage area and medical-examination area) for the taking in of casualties at the time of a seismic disaster and to examine requests concerning construction and necessary equipment, based on hearings with 34 key disaster institutes throughout Japan. From a series of analyses, we evaluated the current conditions for setting up medical first-aid stations in each hospital and determined requirements and factors for disaster casualty intake that should be considered at the time of institution design.
The purpose of this study is to clarify the motion space necessary for assistance around the bed, such as excretion assistance, bed bath assistance, position change, sheet exchange, and transfer assistance from a wheelchair to bed. 1.In the cases other than transfer assistance: The motion space required when the bed is placed parallel to the wall is 3200mm × 1883mm, and when placed vertically, it is 2578 mm × 2924 mm. 2.For transfer assistance: The motion space required for transfer assistance is 3054 mm × 2361 mm.
This study aims to clarify the management situation and facility planning of medical centers for dementia in Japan. We analyzed by the following two aspects. 1. We analyzed the management and facility plan from questionnaire survey for designated medical institutions in Japan. 2. We grasped facility plan of three kinds of medical centers for dementia by visit hearing investigation. We grasped that medical centers for dementia use existing spaces in medical institutions and need spaces for differential diagnosis.
Reconstruction of government building is increasing. Attention is being paid to creating a space for the residents in the government building. On the other hand, another attention is paid to the coproduction where the administration cooperates with the residents. In this research, we focus on the secretariat of the federation of neighborhood association and show the possibility of city hall with corporation space.
The city of Hjørring, Denmark carried out an overall public school consolidation/closure, closing 12 out of 27 schools. This paper presents a case study of planning methods and outcomes of the reform. Small rural schools were closed and those that were not were organizationally consolidated to form school-systems together with a number of schools. This method allowed to increase operational efficiency while maintaining local schools. In several areas where public schools were closed, parents and residents established a private school (friskole) to maintain a local school. Complementing the closure of public schools by self-established private schools was a characteristic phenomenon.
This research focuses on the relationship between the spatial self-position-detection with landmarks and the function of the visual field. 28 college students participated in the experiment were asked to move the center of the landmarks in virtual environment. By measuring the difference between the stopped positions under each condition and the exact central point of landmarks, the accuracy of the spatial position detection was quantified. The results indicate that the central visual field within 5 degrees and the visual field of 15 to 20 degrees of vision centered on the fixation point play a large role in the self-position-detection.
Attractive city night views often contain various window lights patterns. They seem to have characteristic charm different either from illuminated building views or from city bird’s-eye views at night. This research examined the physical formation of window lights patterns that influenced the impression. Using an originally developed program, the authors simulated window lights patterns in two-dimensional monochrome pictures and asked 54 subjects impressionistic evaluation questionnaire. It revealed that the ratio of the area recognized as light to the whole façade has an effect on the sense of security, but not that the more the light the safer people feel.
A T-corner and a step were constructed in the virtual environment. Three experimental conditions were created by changing the distance between the step and the corner, 0 mm, 700mm, and 1400mm. In conditions of 0mm and 700mm, the subjects tend to gaze the pedestrian by decreasing the gazing duration to wall rather than step, and foot tracks tend to become inefficient. Since this tendency could not be found in the condition of 1400mm, it was suggested that the step can be safely and efficiently walked.
This paper reports on the effectiveness of “user participation” conducted during the design, construction and completion stage with the disability group in refurbishing the public facilities. With development of law, “universal design” concepts have been widely adopted in the construction of public facilities. Though mandated criteria have been met, disabled individuals have encountered difficulty in using some public facilities. To address that problem, it was hypothesized that user participation conducted with disabled individuals may be effective. It is shown that there are four vital aspects to interactions between client, designers, constructors and disabled individuals: conditions adjustment, confirmation/decision, improvement understanding, and consensus-based decision making.
Brand building and marketing are known effective value creation means for companies and businesses. This paper reports on the innovative application of such brand building methods (Brand Value Creation) in a large scale redevelopment project for Shibuya Sakuragaoka, and provides an assessment of its benefits: the architecture becomes distinctive brand symbols, achieving synergies with other brand marketing symbols, and delivers higher income and return on investment by delivering higher customer value.
In urban redevelopment project of Fukui station west exit central area, several measures have been taken to establish development in local cities. One of them, the construction of a plaza by original method is contributes to improvement of business profitability and creation of public space. Report this case as an advanced example of public-private partnership in local cities.