Buildings should be constructed under suitable execution circumstances according to users’ requirement quality. From this concept, actual construction experiment of concrete slab was carried out. When quality grades of flatness were shown, the finishing worker replied execution circumstances to achieve them. Most of differences were ways of screeding. After approving by the construct superviser, slabs were constructed under these circumstances. Then they almost became slabs of demanded quality. But when the high quality was required, the grade was not achieved partly.
Technical feasibility to mix-in IC tags into ready-mixed concrete is discussed, focusing on RF communication performance under flowing conditions. Firstly, flowing conditions (i.e. flow speed, concrete thickness) at agitating truck chute and pumping pipe is summarized based on on-site measurement and standard specifications. Secondary, experimental method and RF communication performance index for RF communication is proposed. It has been estimated that 20-40% of IC tags could be found and captured, while non are data read-writable. On-site experiment result was highly consistent with the experimental estimation.
There are over 800 high-rise buildings of height exceeding 100m in Japan. Due to a growing performance requirement in buildings, the demand for demolitions and rebuilds are expected to rise. By anticipating future needs, we have developed a new technique for demolishing high-rise buildings. The roof is kept intact, creating an enclosure at the top of the building. Closing off the work area resolves the common concerns of demolition work while reducing the construction time. Moreover, this sophisticated, environmentally-friendly demolition technique utilizes power generated when the crane unloads dismantled materials.
Applicability of hydraulically expansive-type steel pipes as a linear or planar lift-up system for correcting irregular subsidence of detached housing has been experimentally investigated using two types of scale model foundation, i.e. of single or double reinforcement. The summary of this report is as follows: 1) These pipes successfully separate the model foundation from the ground about 20 - 30mm in height by hydraulically expanding of 25MPa. 2) Strains occurred inside the foundation with single reinforcement during lift-up by various patterns of pipe arrangement have been measured, and patterns to lift-up foundation without damage have been found.
A tracing survey to clarify the improvement feature of masonry garden walls ranked in the poor quality at 1980 (two years later from the 1978 Miyagiken-oki earthquake) was performed. The result of the inspection indicated a feature that over 80% of houses which had poor walls have been improved toward the safety. Some findings for studying how to evaluate the improving situation were also obtained. Investigation shows that a numerical method using the logit conversion could be a useful tool for the evaluation.
A questionnaire survey was conducted to makers of seismic isolators, the construction companies and design companies, aiming to grasp the situation of research of aged deterioration of seismic isolators. The seismic isolator under study is 3 types, lead rubber bearings, high damping rubber bearings and natural rubber bearings. According to the answers of the questionnaire, all of them admit the importance of the research, but they indicate that there are some improvements on carrying out it.
We performed benchmark tests for the strong motion prediction methods using stochastic Green’s function method. Previous papers (Parts 1 & 2) assumed hypothetical sources and subsurface structures. In this paper, the 1923 Kanto earthquake (M7.9) is considered as an actual source, and the Kanto sedimentary basin is used for structure model. All the results calculated by participants generally show a good agreement to each other, in spite of the complicated analytical condition such as oblique incidence of SH and SV waves. The results are also compared to those from an empirical attenuation model, and the discrepancy of the response spectra is discussed.
In recent years, the seismic observation records near the earthquake fault were obtained by development of the seismic observation networks. These seismic observation records show that the earthquake motion near the earthquake fault may far exceed the earthquake motion that is taken into consideration on the conventional design. Relative displacement may be set to 1 m or more to such an earthquake motion. It is necessary to design in consideration of the collision between a superstructure and a retaining wall. In order to use for the retaining wall collision analysis of the base-isolated buildings, design case questionnaire was carried out.
A simple evaluation method for amplification of response spectrum by surface strata is proposed. The proposed method does not require any time history of design ground motion. That means the proposed method can be utilized in response and limit capacity calculation. In the proposed method, the response spectrum of design ground motion is converted to equivalent power spectrum density. The transfer function of surface strata is evaluated by one dimensional elastic wave propagation theory. The power spectrum density at ground surface is converted to response spectrum using peak factor. The good accuracy is achieved in evaluation of response spectrum amplification.
Many seismic records were obtained during the 2011 off the Pacific coast of Tohoku Earthquake. It is very important to use them efficiently for the improvement of the buildings seismic design and the disaster prevention. In this paper, seismic simulation analyses of a SRC high-rise building located at Tokyo bay area were conducted based on the observer records. Nonlinear SR model was used for the analyses. The analysis results corresponded to the records well. Then, the efficiency of the soil-structure interaction and the variation of the 1st dominant frequency and the damping ratio during the earthquake were studied.
This paper presents system identification of the vibration characteristics for a high-rise building using continuous seismic records. The building is 95m height, plan of a square 30m on a side and it was completed in November 1990. The records of seismic observation have been collected in two horizontal directions and vertical direction on each measuring floor in the building since September 2010. It is identified characteristics of natural frequencies and damping ratios based on continual observation under microtremor, strong wind, and seismic ground motion.
We performed a benchmark test for strong motion simulation methods using numerical methods (finite difference method and finite element method). We simulated four observed earthquakes considering a Kanto basin model. All the results calculated by six teams from different institutions generally show good agreement to each other. We found that the choice of grid space makes difference of allocation of soil parameters near the surface. It generates difference of waveforms.
We conducted a benchmark tests for the strong motion simulation methods using various theoretical methods (the wavenumber integration method, the discrete wavenumber method, and the thin layer method). For steps 5 and 6 in 2011, we conducted benchmark tests for actual sources in the Kanto sedimentary basin, such as the 1923 Kanto earthquake (M7.9). All the results generally show good agreements among simulations, but the surface waves seen in later part of observed ground motions were not reproduced well due to the limitation of use of flat-layered half-space models.
In this Paper, an analytical study using 3-dimensional FEM was carried out for the reinforced concrete shear wall tests under cyclic loading to estimate the damage index to the structure from the aspect of energy consumption. First, the validity of the analytical method was confirmed by the load-displacement relationship and the condition of the cracking. Next, energy division between re-bar and concrete is studied and it was suggested that there is a relation between damage of the structure and the strain energy of the concrete numerically. This damage index could be used to evaluate damage of the reinforced concrete shear wall instead of using shear strain of the wall.
In this paper, a static collapse analysis method for cyclic multipoint-loaded structures using the displacement control is proposed. Then, It is confirmed that this method can be applied to the post peak analysis and the cyclic loading analyses by an example problem. In this method, “loading element” is proposed. This element calculates inner forces so that given load ratio conditions are always fulfilled. For application to the existing analysis program, we only have to add this proposed loading element. So, application of this method is very easy and simple.
We introduced the new groundwater measurement technique using a SWS test hole, a foraminate pipe and an Alternating Current (AC) resistivity sensor. A number of in-situ experiment was carried out to examine the effectiveness of the new technique. Two dimensional seepage flow analysis (FEM) was also carried out in order to simulate the groundwater flow surrounding the SWS test hole numerically, and it was found that the new technique may become an effective tool for the simple soil classification.
The vertical bearing capacity of bored piles is examined by 4 full scale pile loading tests varying the strength of soil-cement in the enlarged base. Based on 3 failure patterns of the enlarged base, the end bearing capacity is estimated by the soil SPT values and the unconfined compressive strength of the soil-cement. The pile loading tests show that the relation between the strength of soil-cement and pile bearing capacity agrees well to the proposed failure condition by the simple analytical model.
This paper describes the development of cast-in-place concrete piles at the dawn of Japanese foundation technology. The first cast-in-place concrete pile was compressole pile imported from France in 1907. The compressole pile was formed by dropping a hammer on the casted concrete in an excavated hole. Those piles installed at those days still exist in a number of historical buildings during more than 100 years. Following the compressole pile, abbot pile was introduced from the United States in 1910. The abbot pile is same manner to compressole pile, but using a casing tube to make a drilled hole.
The N-value of soil in the pressurized sand tank was necessary for comparing the results of loading test on model pile and actual pile. The relationships between relative density after pressurizing the soil, vertical loading pressure and the N-value were obtained from the standard penetration test in the tank. Using these relationships, the relationship between the bearing capacity of the model pile and the N-value was determined. By comparing this relationship with similar relationships obtained from the loading tests of actual pile, the results of model loading test using the tank and those of the standard penetration test were validated.
This paper reports the result of case studies for a large scale dome structure with a diameter of approximately 300m. Schematic designs of a total of four domes are conducted to quantitatively evaluate the advantages of using high-strength steel and/or seismic isolation. It is shown that the unit structural weight of the dome with high-strength steel and base isolation can be as small as half of the one without the two.
It is well-known that the dowel plays the very important roles in the wood siding wall system in the traditional wood structures. In this paper, element experiments on the dowel of siding wall are performed under monotonous and cyclic loadings, and the influence of length, depth and the shape of the section of the dowel on the elasto-plastic characteristics as the transmission device are investigated and discussed. Also, the dowels composed of the wood and the lead are presented and examined, compared with the ordinary wooded ones.
As a new kind of seismic materials, superplastic Zn-Al alloy has been studied and proposed. This alloy has a few advantages such as low work-hardening rate and high ductility over a conventional seismic material, for instance, a low-yield-point steel. In this work, a superplastic Zn-Al alloy seismic damper is developed to improve the seismic performance of traditional wooden structure. In order to verify the effect of developed dampers, fundamental performance tests and dynamic loading tests were carried out. Results of these tests indicate that this damper shows stable hysteresis loop from small to large deformation and a traditional wooden structure with this damper has large damping capacity.
The general method for strengthening unreinforced concrete foundation beams of wooden houses against earthquakes is to arrange reinforcing bars and to cast concrete along the existing foundation beam. The construction cost of this method accounts for major percentage of the total construction cost for strengthening. A new method for flexural reinforcement with steel channel attached to one side of unreinforced concrete foundation beams was developed, which can reduce the cost. Bending moment tests were carried out to check the structural performance. A formula to predict the flexural capacity was obtained as a result of experimental and analytical studies.
A buckling-restrained brace showing the effectiveness in earthquake-resistant and vibration-controlled technologies of steel structures is applied for RC structures. In this case, the technology development for the most suitable connection is required to solve problems of existing connections. The authors have proposed a new connection method. In this paper, 1/3 size specimens of the new connection method are tested. The good structural performance of the specimens has been confirmed.
In this paper, the influence of multiple web openings on RC footing beams is investigated. Three-dimensional finite element analysis considering the non-linearity of both concrete and rebar is used. Simulation analysis of previous experiment is firstly conducted for the evaluation of the accuracy of our analysis. Stress conditions and crack distributions between experiment and analysis are compared. Further analyses are conducted with new model with different arrangement of small unreinforced openings. Finally, the influence of small web openings to the beam stiffness and strength is discussed.
A reconnaissance of steel school buildings damaged by the 2011 Tohoku earthquake has been conducted by the Architectural Institute of Japan. This paper discusses the various types of seismic damage to vertical braces observed in 129 school buildings. The braces of pre-1982 buildings which were either unretrofitted or not seismically evaluated suffered more damage, compared to either pre-1982 retrofitted or post-1982 buildings. Most of the damage to connections in older buildings are caused by either old design practice, where the connection strength does not exceed the brace strength, or improper construction.
A reconnaissance on the damage to school buildings caused by the 2011 Tohoku earthquake was conducted by the Architectural Institute of Japan. This paper focuses on reporting the damage induced by the tsunami along the Pacific coast of Northeast Japan. Excluding 2 collapsed gymnasiums, the rest of the buildings suffered none or slight damage to the structural components such as cracking of the base concrete or slight bending of the vertical braces. Most of the severe damage was observed in the nonstructural components such as the exterior walls which were caused from either the dynamic water pressure or floating debris.
The authors have been developing low-rise reinforced concrete masonry buildings with the wall thickness of 150mm, for the purpose of the increase of inner space of buildings, the decrease of building weight, and the usage of the standard building module of 300mm. In order to realize the buildings, compressive behaviors of fully grouted masonry prisms, using small-size concrete units with a strength of 40N/mm2 class and various grout materials with a strength more than 50N/mm2, were investigated. The used materials are concrete, mortar and non-shrink grouts with or without aggregate.
We report the changes in out-of-plane vibration characteristics due to the seismic retrofit of historic masonry buildings based on the result of microtremor measurement. Major findings from the research are as follows; (1) Natural frequencies increase nearly 1.1 to 1.9 times by reinforcement. And, the increasing rate of natural frequency becomes smaller as it becomes high order. (2) Using steel frame for reinforcement, out-of-plane deformation of masonry wall is restrained. And, using shear wall, it is restrained greatly. (3) 1st damping factor doesn’t change remarkable by reinforcement.
Sprinklers are the most popular and reliable system for controlling fires. But the studies on smoke behavior with sprinkler activation are hardly studied. In This paper, smoke behavior with sprinkler activation was studied. Experiments were conducted on a full scale and the following results were obtained; the temperature of the upper layer was decreased, and the lower layer was raised by effect of water spray. As amount of water increased, CO2 density of the upper layer was decreased and lower layer was increased.
Regarding scattering coefficient that represents acoustic scattering of wall surfaces, a reverberation room method for measuring the random-incidence value has recently standardized by ISO 17497-1. The scattering coefficient is widely used in geometric room acoustic simulation, however, there are few measured data available. In this report, a variety of rib and block structure walls are tested by the reverberation room method in order to provide a database of scattering coefficients. Furthermore, characteristics of the scattering coefficients are investigated, especially regarding the effect of surface profile and absorbent finish for rib structures, and that of arrangement for block structures.
To examine humidity influence on stability of pu-sensors, we applied calibration and the ensemble averaged surface normal impedance method (EA-Method) under controlled relative humidity (φ=35-60%) in a reverberation room. Experiments revealed that calibration results (i.e. correction values) changed as humidity levels varied. A comparison of standard deviations on absorption coefficients generated increasing value as the humidity difference between calibration and measurement increased (Δφ=0-25%). Repeatability was demonstrated by using two identical pu-sensors in four set measurements. Furthermore, a partial correlation test demonstrated the dominance of humidity over other environmental factors influencing sensor sensitivity.
The purpose of this report is to clarify the effects of sound insulation achieved by installing partitions on a counter. From the results of numerical experiments, the following aspects were clarified. When two parallel partitions are installed on both sides of a speaker and a listener, the sound pressure level at the waiting area is raised. When some booths are compartmentalized on a counter using parallel partitions, the sound insulation to other booths cannot be achieved in the case of partitions with a low absorption coefficient but can be achieved in the case of partitions with a high absorption coefficient.
In this paper, we have examined the forecast of heavy-weight floor impact sound level in the housing using the Finite Element Method (FEM). Analysis object is a heavy-weight floor impact sound of dry double floor construction to the laboratory wall construction. 63Hz band analysis results is included in 65% (within ± 5dB) the difference between the measured and analysis value, the result was good correspondence. In the evaluation of the L-value, prediction of heavy-weight floor impact sound of dry double floor using the FEM is a sufficient prediction accuracy.
We used a full-scale model floor to investigate the impact of edge fixing on the impedance characteristics of wooden floor structures. Our investigation yielded three key conclusions: 1) Joists in wooden floor structures essentially function as simply-supported beams held at both ends. 2) When the wooden joists have standard cross-sectional dimensions, edge fixing increases the driving-point impedance in impact time since the driving-point is very close to the end of the joist. 3) The use of adhesive in addition to screws on structural members in the floor delivers no significant benefit in terms of the impact of edge fixing.
The attic in a house can be utilized for storage space but the thermal condition may not be suitable for such usage. In order to keep temperature in attic within a moderate range, it is well known that improvement of insulation and solar reflectance of roof are very effective but the combined effect of roof insulation and solar reflectance has not been discussed. In this study, such combined effect is examined on the basis of measured data in full scale house models and results of numerical simulations. The simulated results show good correspondence to measured data and numerical simulations under various conditions are conducted. This paper also gives the charts in which appropriate insulation performance and solar reflectance of roof can be selected according to requirement for attic space.
An enclosed demolition method for high-rise buildings is developed by the authors. It is expected that this method improves the thermal environment of demolition work-space by blocking direct solar radiation. This paper describes the results of a thermal environment evaluation based on field measurements and numerical simulations. Blocking of direct solar radiation significantly decreases WBGT in the work-space. Moreover, openings that are designed to promote natural ventilation help exhaust high-temperature air from work-space efficiently. Based on the results, it is believed that this enclosed method decrease the risk of heat stroke for demolition site workers.
Many investigations have been performed concerning energy consumption of individual households. However, there are few surveys on energy use of common equipment in multiple dwelling houses. The purpose of this study was to clarify the energy consumption characteristics of common equipment in multiple dwelling houses. We measured the electric energy consumption of common equipment such as common space lighting units, elevators, water pumps and domestic waste water treatment units at 4 high-rise multiple dwelling houses in the Tokai district. We presented the annual and daily variation in electric power consumption of each usage.
The main purpose of this study is to evaluate thermal comfort levels in traditional Malay houses based on a field measurement, with an interest to apply its traditional passive cooling techniques to modern houses in Malaysia. The results reveal that indoor air temperatures are 1-2°C higher than the corresponding outdoor air temperatures throughout the day except for a few morning hours around 9 a.m. Air movement obtained by open windows or ceiling fan is required to lower the SET* and improve thermal comfort. Solar heat control and a cool microclimate might be two fundamental traditional cooling techniques for these lightweight houses.
Residential and commercial building sector accounts for more than 30% of final energy consumption in Japan and an increase from the past is remarkable. In order to realize a low-carbon society, further strengthening of energy saving measures is essential. Japanese government is considering a mandatory policy scheme which forces all residential and non-residential buildings to meet the energy efficiency standard by 2020. This research aims to marshal trends on regulations for energy efficiency of residential and non-residential buildings within countries which implements advanced measures, and to obtain referential knowledge for Japan’s energy efficiency measures.
It is necessary to consider measures to promote well insulated houses toward the reduction of CO2 emissions in residential sector. However, it is difficult to determine effective measures since residents’ attitude toward introducing insulation differ from one by one. Therefore, in this study, a model for predicting the diffusion process of well insulated house was developed taking residents’ attitude toward introducing insulation into account. The model enables us to consider effective measures for promoting well insulated house. As a result of case study, presenting energy benefits and non-energy benefits was more effective than giving economic incentive in the study.
Umeda River was a city river of Sendai city. This river had become ditch for the urbanization of the basin in the short term number ten years ago. It was improved to some extent now. The authors start the investigation of the Umeda upper part of a river basin in 2006 and investigate the distribution of the small branch and the present conditions and the water. These work were aimed at getting the judgment that was necessary for the aim setting of the environmental safeguard of the Umeda upper part of a river basin.
Main purpose of this paper is to investigate the improvement in energy-saving performance by comparing before and after rebuilding or renovation of the public rental housings based on statistical approach. For this purpose, actual data and information related to annual energy consumption, environmental awareness and lifestyle are collected through the questionnaire to the tenants. Electric power, city gas and water consumptions are decreased more than 10% by introducing latent heat recovery type hot-water supply machine and water-saving toilet system and shower kit etc., although living comfortable level after rebuilding is improved by bathtub enlargement and three-place hot-water supply system. We also accepted the weak correlation between the environmental awareness level and energy consumption volume. We believe that this correlation strongly suggests the further energy-saving potential without additional facilities installation.
In the local city area, many historical districts have subjects such as growing aging and vacant houses. The multi generation residence style is useful for the improvement of these subject. This study aims to consider the residential environment and the case study for multi generation residence in historical district. In questionnaire for householders in Hirose, 50% hope living together, and 22% hope living of short distance. In case of research for multi generation residence, old store spaces are utilized young generation’s private space, and how to make the common spaces require considerations to the difference in the lifestyle between generations.
The purpose of this paper is to examine the actual use of fumarole gas fixtures in Takenoyu and Tsuetate areas, Kumamoto Prefecture; Kannawa area, Oita Prefecture; and Unagi area, Kagoshima Prefecture. Some features were discovered by conducting field investigations, interviews and questionnaires for residents in each area. The variety of geothermal energy potential and appearance causes the difference of fumarole gas use and expansion process of these areas. Investigating some features of the actual use of fumarole gas fixtures is useful for creating the low environmental load and high-quality living environments.
Many modern planned residential area, especially new town do not have original souvenir and picture postcard which support identity of community. From 2002, we developed the 850 picture postcards which express the attractive scenery and history of the Senri new town, first large-scale new town in Japan. We found these community picture postcard are useful as 1) communication media of residents, 2) indicator of important landscape, 3) record for change of town, and 4) fund for local NPO group.
This paper mainly clarifies subdivision of the east shrine town in Miyajima. The acquired knowledge is shown below. Miyajima’s town composition was converted to a row-shaped configuration of the composition centering on a street parallel to the coastline from the composition centering on an alley. Miyajima formed a neighborhood association and disaster prevention space in the residence area. In Miyajima, the town area is intentionally formed based on marine reclamation.
The purpose of this study is to investigate the space which has a role of encouraging users’ independence in Self-Support Home. A variety of building types and capacities were found which relate with staff’s concepts of supporting. As a result of comparing with a child welfare facility, we found it important to prepare enough public spaces for talking with staff as well as user’s single room for privacy. Also, it is required to choose appropriate room for each activity in order to realize the concept.
Occurrence frequency of rainfall with wind is important data for design of external building system. This report is considered in the point through data processing of 1 hour rainfall and 10 minutes mean wind speed for about 20 years in 98 surface weather stations in Japan. Then it shows maximum wind speed occurred once a year according to 4 kinds of rainfall by each station, and trial proposal classified stations by this maximum wind speed and the point data of occurrence frequency of rainfall with wind.
The study revealed following results about the change of the relationship of the spatial composition of plumbing area in two houses, main house and boathouse, in the ine coastal village. Although the connection about a toilet exists, it is a decline tendency. The connection about a bathroom and a kitchen does not exist. As time passed, two houses become independent each other, because of a addition tendency for a toilet in a main house, a addition tendency for a bathroom in a boathouse and a tendency for a kitchen to be installed in both of two houses.