The imperfect placing joint of concrete not only spoils the fine sight of a concrete structure, but has serious influence on the durability of concrete. In this study, the specimens of concrete which is used moderate heat cement and fly ash are prepared to have same compressive strength which is used normal portland cement, and the placing time interval and the placing method is selected as examination index. The quality of the placing joint of the concrete which is used moderate heat cement and fly ash is good as compared with that of ordinary portland cement.
This paper describes the study on the predicting method of the dry density for the shield concrete. A series of experiments was conducted based on the method considering materials and mix condition variability. The following conclusions can be drawn. The correlation between the density of fresh concrete and the dry density is high for all concrete materials and mixing conditions. From this result, it can be possible to estimate the dry density of concrete by managing the density of fresh concrete for the actual construction works.
Asbestos cement sheets used under outdoor condition may need surface treatment because of deterioration. Surface preparation of deteriorated asbestos cement sheets may cause asbestos fibers release during surface preparation. However, technical information about fibers release is not enough to design countermeasures for surface preparation of deteriorated asbestos cement sheets at present. In this study, airborne fibrous particles concentration was measured under several ways of surface preparation of existed deteriorated cement sheets containing asbestos, and asbestos fibers in waste water and dust were also analyzed in order to develop safe surface preparation methods for deteriorated asbestos cement sheets.
Considering the seismic hazard of locality and aging deterioration of a building is indispensable, to estimate the effectiveness of Earthquake countermeasures for a big earthquake assumed to occur dozens of years later, to investigate necessity of maintenance to make an building of high performance for long life. Therefore this paper suggest the idea of earthquake countermeasures for local wooden house through the case study for traditional wooden houses by using a previous seismic risk evaluation technique that can consider durability and deterioration of a building.
The methods of structural test and evaluation applicable to steel wall system were developed in order to verify wind-resistant performance of the system. They were incorporated in the Standard of Steel Wall (SSW2011). The authors developed the methods in the viewpoint of performance-based structural design so that the concept of structural verification using them follows Building Standard Law of Japan. This paper outlines the detail of the proposed methods along with technical backgrounds.
Force restriction of the tuned viscous mass damper is considered using a friction slider. From a series of shaking table tests, it is shown that the restriction mechanism can effectively reduce the damper maximum force, and the maximum displacement of a primary system incorporated with the force restricted damper is almost the same as that with a restriction-free damper. The simulation analysis results show good agreement to the experimental results, and the relationship between the ratio of the force restriction and the maximum displacement is examined by the analyses.
Response control using inertial mass element which gets inertial force due to the relative acceleration is recently studied by many researchers. The authors have proposed a new seismic response control system, the tuned viscous mass damper (TVMD), composed of arranging viscous damping element and inertial mass element which has an apparent mass amplifying mechanism to obtain a large supplemental mass effect in parallel and connecting spring element in series. This paper shows the application of TVMD to a high-rised steel building structure and response control effect of this system.
The 2011 off the Pacific coast of Tohoku earthquake generated the main shock with long-duration and long-period and the magnitude 7.0 class aftershocks many times in a wide range of eastern Japan. The horizontal displacement response of the isolated building caused by them was about 0.4 m. They damaged seismic isolated dampers such as steel dampers and lead dampers. This paper presents to evaluate responses of isolated buildings and the damage of seismic isolated dampers by results of response analysis using simple isolated building model under bi-axial horizontal loading in main shock and aftershocks observed at 6 points from Aomori to Tokyo.
The authors conducted a questionnaire survey to the residents of super high-rise residential buildings in Tokyo, on the responses of them due to the 2011 off the Pacific coast of Tohoku Earthquake. The important results are: (1) Due to the large shaking amplitude, residents’ behavior was considerably affected. (2) The furniture overturned or moved severely, especially on the upper floors of tall buildings which have less than twenty stories, in the conventional structures’ cases. In the base isolated buildings, the damage was much smaller than that of conventional ones.
Velocity-dependent dampers have high ability to control responses for not only large but also small vibration. The direction of deformation in these dampers is generally limited to one direction. In the case that direction of damper’s axis coincides with direction of excitation, damper dissipates energy most efficiently. However in practice it is relatively rare that the direction of damper’s axis coincides with that of excitation. This paper presents that the energy dissipation of velocity-dependent dampers that have nonlinear relationships between velocity and damping force is greatly influenced by difference in excitation.
The failure of the large suspended ceiling systems has been one of the most widely reported types of nonstructural damage in building structures in past earthquakes. The results of shaking tests at some input levels showed the dynamic characteristics of the suspended ceilings and some ceiling specimens were damaged in a form which will lead to a successive collapse of a large suspended ceiling. This paper discusses an effective method of the clip connections which are developed to reduce the likelihood of the ceiling failure.
The objective of this paper is to analyze the effect of deformation control systems against pulse-like ground motions. In this paper, we carried out time history response analysis for the models of the equivalent SDOF system and the MDOF system equipped with hysteretic dampers, viscous dampers and stoppers. As a result, the following conclusions are obtained. 1) Against the maximal pulse-like ground motion, it sometimes happens that the additional hysteretic dampers increase the maximum story drift angle. 2) In all the cases, the additional viscous dampers decrease the maximum story drift angle. 3) Equipped with stoppers, there is a possibility to control unreasonable deformation against maximal pulse-like ground motions.
There are few researches in the combinations of dampers with different performances in vertical direction. The authors proposed the “combination-system” which is constructed of hysteretic dampers arranged in the lower stories of the building and viscous dampers arranged in the upper stories. This paper presents earthquake response characteristics of “combination-system” based on time-history analysis results. In addition, this paper describes the effect of the arrangement pattern of dampers and an amount of each damper to vibration control effect of building. This system can absorb the seismic energy compared with the one type of damper system.
In this paper, a new outer-frame system is proposed to retrofit the existing building. The outer-frame system consists of a Visco-Elastic Damper and an Axial Force Transfer Mechanism. To make clear the mechanism of the outer-frame system, static tests of full-scale frame model were conducted. Additionally, the frame analytical model is proposed for structural design. As a result of static tests, the hysteresis characteristics of the outer-frame system show the stable characteristic, and energy absorption performance increases according to a deformation angle. The proposed analytical model can be approximated with sufficient accuracy compared with result of static tests.
In evaluation of 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. Therefore, it is important and necessary to grasp dispersion of wind response from small number of samples. In this paper, the dispersion of wind forces and wind-induced responses are investigated from wind tunnel tests. Then, the influence on wind responses due to the difference in the number of samples used as an ensemble average is elucidated.
Winkler model is widely used in the analysis of foundations. It is usually employed in the transfer matrix method for analysis of laterally loaded piles, but it is difficult to take account of the model in the stiffness matrix of the grid beam structures. On the other hand, since in the stiffness matrix the soil supporting beams is modeled by only concentrate springs, many elements are needed to obtain the correctness of calculated quantities. The authors present the convenient method transforming from the transfer matrix to the stiffness matrix for the analysis of the grid beam structure on the soil.
In this study, composite beams with timber and steel were tested and its strength was evaluated using superimposed strength and ultimate strength theory. Four types of specimens were as follows: (A) Timbers reinforced with lag screws(LS6) 50mm pitch, (B) timbers with steel plates (PL3.2) 3.2mm thickness put on top and bottom sides, and fasten with lag screws 50mm pitch, (C) timbers of (B) with cover woods on top and bottom sides, (D) no reinforced timbers. These specimens were experimented by three-point bending test. As the result of this experiment, it was found that 1)steel plates reinforced a timber beam effectively, 2)ultimate bending strength of B-series and C-series could be evaluated by superimposed and ultimate strength theory.
The lattice shear wall consists of the combination of square section lumbers. In this paper, authors developed the lattice shear wall which is composed of logs as columns and steel pipes as nuki. Its structural performance was estimated by mechanical model and confirmed by strength tests. Due to the high transversal compression stiffness of the steel pipe nuki in compared to the lumber nuki, the developed shear wall showed the higher mechanical properties than the general lattice shear wall. In addition, it was possible to make initial slackness relatively smaller without using wedges by laterally compressing steel pipes after assembly.
The system enabling to build the shear walls using Japanese cedar planks more ductile, resistant and easy than the conventional method, was studied. New fasteners to connect planks on shear walls were developed by utilizing the compressive strength of wood in parallel to the grain and four types of shear walls were made for the full-scale shear tests. As a result, S.R.F with 1P-size shear walls were found to be 2.4, 3.2 and 2.5 and also Shear Resistance Factor with 2P-size one was 2.7. All the shear walls have been found with the high ductile performance of over 1/15 radian.
It is well known that timber buildings often suffer damages under maximum earthquakes and some problems of existing non-conformity buildings in Japan have to be solved. In this paper, we choose a certain temple in Tokyo, for which a base-isolated retrofit is constructed, to reveal its own structural properties. We make seismic diagnoses including limit strength calculations. We also conduct micro-tremor measurements and earthquake response analyses.
In Japan, whenever the severe earthquake occurred, many residents were injured or died by the collapse of old wooden houses with poor seismic strength. However, the seismic strengthening for existing wooden house is not carried out in Japan. The reasons why the resident dose not carried out seismic strengthening are high cost, long work period and so on for retrofit works. We developed the new seismic strengthening method by the thick plywood with openings; the high wall strength performance was obtained by the proposed strengthening method. In this study, the horizontal loading tests for some kinds of thick plywood with openings were carried out.
Research and development on a new precast concrete system that beam-column joints are manufactured as the precast concrete has been conducted for the purpose of more efficient use of precast concrete technology. In this study, the loading test is conducted for beam-column joint specimens to investigate the structural performance. From the test results, no large differences between precast and cast-in-situ specimens can be found out in terms of failure progress, shear force - drift angle curve, deformation components and damping factor. It can be recognized that the structural performance of precast beam-column joints shows the same performance of cast-in-situ joints.
In the 2011 off the Pacific Coast of Tohoku Earthquake, many seismic retrofitted buildings were subjected to strong motion. The 10-story residential building that was retrofitted using damping system with amplifier mechanism was one of these buildings. In order to verify the effect of seismic retrofitting, we investigated the building condition and calculated story drift angle by seismic response analysis. As a result, the safety of this building was confirmed. Furthermore, we verified when partial walls were in failure using the modified compression field theory. It is concluded that the effect of partial walls on structural performance was less.
In regions with heavy snowfall, such as Akita, the primary load on the structural design of school gymnasiums is the snow load. However, for recording heavy snowfall, the regional distribution of the snow load is modified. As a result, the amount of snow load to be considered in the seismic diagnosis of gymnasiums is not clear. Occasionally, these gymnasiums are unable resist the long-term load during heavy snowfall. In this study, the annual transition of the snow load on a structural design was investigated using the past records for a prefecture and a self-governing body.
The authors designed an innovative steel skin roof, of which considerable amount of tension is introduced into the surfaces. By conducting the structural experiment of two stages, inflation test and loading test on a specimen of a practical size (span:10.8m), structural performances of the roof are evaluated in this paper. The principal conclusions are as follows: 1) A simple formula was proposed to express progresses of tensional stress during inflation. 2) The specimen showed strength increase as well as considerable deformability even after the backup folded plate suffered local buckling. 3) Structural feasibility was showed by carrying out an allowable stress design on temporary load.
The authors have proposed mid-floor leveled column base system. The first story columns consist of the reinforced concrete downside column and the steel topside column, and their joints with the anchor bolts and the shear plates are supposed to be pinned. In this paper, the building designed by using mid-floor leveled column base system of applicability and seismic performance are studied. In order to compare mid-floor leveled column base system and conventional column base system, the building designed by using exposed type column base and embedded type column base are studied.
To enhance the usable life of existing steel buildings, a strengthening method with bonding continuous fiber reinforced plastics (FRP) plates has been developed by authors. Deep corrosion was observed in a chemical plant frame bleached in chemical atmosphere for a long term. 40% lack of beam thickness was confirmed in the frame. The frame is appointed in an explosion-protection area, and a constructer cannot use fire during rehabilitation and repair. Therefore a strengthening method with bonding CFRP was adopted. In this paper the progress of rehabilitation by bonding CFRP plates are introduced. Also, this paper reports the results of bending tests conducted on secondary beams in chemical plant frame before and after rehabilitation using CFRP plates.
Concrete encased steel composite column with steel jacket using recycled concrete is proposed by the authors, and is being conducted continuous studies to make it practical. This paper discusses how to evaluate the axial strength of full scale columns. It is revealed based on the test results that the AIJ design formulas for SRC structures can be applied for evaluating the axial strengths of these columns. Furthermore, improved design formula to estimate the axial strength is proposed for these columns considering scale effect of concrete and local buckling of steel jacket.
Our research group members mainly consisting of university researchers and students have done strenuous volunteer activities for the KAGUTENBOU to provide furniture fixing service for homes. The major factors of the human damage in the previous earthquakes were attributable to the building collapsing and furniture tipping. Fixing furniture is the minimum environmental improvement that has to be quickly undertaken against future major earthquakes. This paper reports the questionnaire survey that we conducted on the residents’ awareness of and preparation for disasters, and the analysis of the survey result, the extracted issues and our activities to solve them.
A significant amount of research on Tohoku earthquake in 2011 reported the damages to nonstructural components. However, the survey on structural characteristics and seismic performance of nonstructural partition wall is scarce. In this paper, we carried out anti-plane static loading tests on partition walls with light-gauge steel and confirmed their behaviors and strength. In addition, their dynamic properties were estimated based on the results.
A questionnaire survey about shaking and damages of the super high-rise RC buildings during the 2011 off the pacific coast of Tohoku earthquake was conducted for the residents. The survey was conducted for 15 super high-rise residential buildings in the Kanto and the Kansai areas in late July 2011, about 4 month after the main shock. The following conclusions were reached; (1) The anxiety during the main shock tends to be higher than the action difficulty with same questionnaire seismic intensity. (2) The relationship between questionnaire seismic intensity and the damages to the interior materials and the concrete member showed an inverse correlation. (3) The questionnaire seismic intensity and the action difficulty, the tendency of damage situations to the interior materials and concrete member differ between 2 buildings which are close to each other. (4) The building that built at an area where significant liquefaction had occurred suffered relatively-great damages. (5) At the lower part of the buildings, many residents heard a squeak sound of building during the main shock or the aftershock.
To reduce the global environment load, a sustainable building structure system (SBS), which is one of the damage control structures, has been researched and developed. However it is difficult for this system to apply conventional facade panels in case of a huge earthquake. In this study, the authors propose a new facade panel system that suits to large story deformation angle of the SBS. Basic performance of the proposed system is confirmed by experiments using scale-down model that have rotational pin and slipping connections.
In this report, it was proposed the method of using existing mechanical smoke exhaust system as pressure relief in lobby pressurization smoke control. It was shown that the case study of the method of the dilution in the crosscut duct and the method of the dilution in the exhaust gas setting up duct was done, and there was a possibility that the existing exhaust gas equipment was able to be used.
8 designs of traditional style bare timber eaves reinforced with conventional building materials to block penetration of an external fire into the building are proposed for the restoration and renovation of historic townhouses in Kyoto. The full scale fire resistance tests on the integrity and the thermal insulation of these designs against external fires revealed that these designs should be rated as either Fire Protective Construction or 45-60min Quasi-fireproof Construction.
A practical technique for simulating room acoustics parameters is proposed. The technique comprises Subsystems 1 and 2, each of which uses photographic images. Subsystem 1 uses a Gray Level Co-occurrence Matrix and a Feed Forward Neural Network to identify material surfaces. Subsystem 2 uses a Dimension Vision Predictor with the author’s “ruler method” to identify the dimensions. Examinations conducted in practical rooms revealed good correlation coefficients of r ≥ 0.90 for Subsystem 1 and r ≥ 0.99 for Subsystem 2. Finally, simulations of reverberation times were conducted using Finite Element Analysis (FEA) with identified parameters. Sufficient agreement was confirmed.
In Japan, it pays attention to a traditional lifestyle that harmonized with nature. A residence using natural energy is one of the effective measures against the global warming issues. Therefore, the proposal of a sustainable design of house and the lifestyle becomes more important to reduce the negative environmental impact. Measurements were conducted in an environmentally symbiotic house with double-deck engawa, the sustainable design laboratory that had adopted a passive technique. In this paper, measurement of natural ventilation effect in summer.
Characterization and emission of indoor sub-micron aerosols have been of great interest. This study aimed at investigating for characteristics of particle concentrations for size distribution in office buildings. The number of size distributions, PM2.5 and SPM (less than 10 μm) mass concentrations were measured in 15 large office buildings that were over 3,000m2 of total floor areas and had central HVAC systems. As a result, the mass concentration shows a bimodal distribution at around 0.2-0.3 μm and 4 μm, while the number concentration has a smaller peak at 0.02 to 0.05 μm. The results of other buildings have the same trend of particle size-distributions. Every mass concentration was relatively low, except for the building, which had smoking area inside. PM2.5 ratios (PM2.5/SPM conc.) were around 0.8, and therefore SPM forms the greater part of PM2.5. The peak of mass concentration distribution around 0.2 μm has a great effect on PM2.5 concentrations. The sub-micron particles might penetrate through filter media in HVAC systems from outdoor air.
Toilets with an uroflowmeter are used in hospital facility. When experimenting on the drainage load before and after the completion, we verified effect of the examination method of the previous report. As a result, if the loop ventilation method of SHASE-S206 was performed, the jurisdiction pressure fluctuation became ±200Pa or less, too. Therefore, the measurement precision was maintained. Moreover, we presume that it can also contribute to lighten the work load of the nurse by the research of usage frequency.
The effect of multiple absorption by the shape of corrugated roof coated with high reflective paint was studied. It is largely affected by multiple absorption in the case of 0.5 to 0.7 solar reflectance of the roof material. If the high reflectivity paint is applied to the corrugated roof, urban heat island measure effects and energy saving effects should be evaluated by using the solar reflectance which is considered the effect of multiple absorption noted in this study.
We studied the actual condition and problems of energy conservation refurbishment projects utilizing the national subsidy system by questionnaire survey and interviews. One of the features of this study is to have grasped the actual condition about frame refurbishment of non-residence buildings with few repair examples. The refurbishment projects are implemented together with replacement of the existing equipment in many cases. And most of them are partial frame refurbishment. One of the subjects both the building owner and the construction builder pointed out was that the unclear cost-effectiveness of frame refurbishment.
In the past two decades, CO2 emissions in Taiwan have sharply increased, but models for forecasting the future trend are still insufficient. In this study, based on the energy consumption of residential sector from 1990 to 2010, CO2 emissions were estimated up to 2050 using the macro simulation method. The model presents the final energy consumption and CO2 emissions by category of fuels and final usages. Several scenarios were applied to examine the possibility of achieving the goal set by the government; the most effective result shows 27% reduction by 2020 and 64% reduction of CO2 emissions by 2050.
Qilou, built in the 1920s and the 30s, and the neighboring urban residence both make particular landscape of old Guanzhou city, China. The study clarified those residential conditions including experiences of rebuilding or restoring as well as residents’ living consciousness. As the administrative authorities have already become aware of the Qilou’s historic values, they made efforts to preserve the Qilou and to regenerate the Qilou district. We made a proposal of rebuilding and restoring on a small scale, in spite of several serious problems preventing residential regeneration in the district.
Compared with in Japan, where study on energy-saving technique started in as early as the 1970s, in China the study has just started in recently years, and has still got some incomplete techniques; moreover, the orientation of technique promotion is different as well. Therefore, the research objective is to find out the problems and propose reasonable suggestion on the basis of survey on the current status of environmentally-responsible technique of housing in China. In addition, it’s expected to put forward the development core issue of the new environmentally-responsible technique in the future by case study with correlated technique in Japan. Moreover, it is respected that through the research, there would be a further realization on the environmentally-responsible technique of housing in China, increasing the technique communication between the two countries, and give a good lesson for the new technique development in the future.
This study reveals the floor plan trend in Fukui, Iwate, and Oita through the research of advertisements in the newspapers and magazines. Viewing 25 years’ trend in the main newspapers in 1980, 1985, 1990, 1995, 2000, 2005, the trend from 2001 to 2007 including the town magazines was also researched. This mainly shows; 1. On the 1st floor, the traditional “DK+Tsuzukima” changed into “LDK+Washitsu”, and on the 2nd floor the Japanese and Western styles “Washitsu+Youshitsu” unified to “separated Yoshitsu”. 2. However, after 2004 the new trend “Passing through public room to the 2nd floor or bath and toilet” appeared.
This study, we got a handle on the characteristics of spatial from relation between children’s activities and spaces. As a result, it became obvious that the variety of children’s activities in after-school daycare centers is not necessarily secured. And, many facilities were not space to ensure free and dynamic children’s activities. It is difficult to each of the activities of static and dynamic can be done without risk. On creating an environment at the facilities, it is important that plan to be expanded the possibility of further activities after securing the floor space depending on the number of people.
This study shows when wheelchairs and baby carriages begin to move at a gentle slope in a certain angle of inclination. We used a swing road to experiment with wheelchairs and baby carriages for an angle of inclination to see when they begin to move. Results of Experiment: 1. Wheelchairs and baby carriages will not move if the frame sat down cross position from incline. 2. If the frame is moved in the direction of the incline, the angle of 1-2 degrees begins the wheelchair to move downward and 2-3 degrees for baby carriage.
This case study examines the seat selection at the time of arrival in a small-scale non-territorial office. The questionnaire to the workers reveals that 23% of workers consider that their seat selections affect their business and 67% of workers prefer to change their seats to avoid other worker’s voice. The observation of the seat selection at the office shows that many workers tend to fix their own seats. Even when they miss the seats, they select another seat in the same area (table). Some particular areas are hardly used while the other areas are frequently selected. And the seats at the corner of each area are occupied first. Some workers select the area where the particular worker sit.
This paper is a study on renovation to make a new skin on building envelope by dry method. The discussion about countermeasures how to fix fall troubles of external finishing which covers GRANDSHIP in Shizuoka City is examined as a case study, the followings are pointed out: firstly scope of consideration to add a new skin to existing envelope is clarified. Secondary the risks of modifying works to envelope are categorized to two types: one can avoid them by modifying design, the other can’t. Finally the process model to compare means of renovating building envelope is proposed.
A trace of the trial and error to then earthquake resistance is kept as modern wooden architecture which was built from 1891 in about 1950 before the Building Standard Law establishment. And we think that there is historic value in a structure technology to be left there. This study aims to obviously the earthquake-resistant structure of modern wooden architecture. The research method adopted surveying and microtremor measurement of the government office institution which was built in 1927. Based on the findings, we analyzed the evolution of the how to structure of brace by a comparison with the documents findings.
This paper aims to obtain the appropriate policy about Harvested Wood Products in the way to clarify the movement of carbon in the life cycle of wooden detached houses. This study revealed that: 1) The amount of the carbon of the wooden house is 20-40% of the log cut down from the forest. And, as for the component ratio of carbon emission by wooden house construction, the circulating carbon in a short span exceeds 50%. 2) The circulating carbon in a short span emissions are greatly affected a yield rate of timber production. So it is important to use the wood of a high yield rate of production to achieve an efficient carbon storage.