The influence of the quality of silica fume on the workability and strength of high strength concrete was investigated, and the following results were obtained. (1) High strength concretes using 4 types of silica fume were all found to have good workability. (2) There was no difference in the strength of high strength concrete structures using the 4 different types of silica. (3) High strength concretes using silica fume as a mixed binder and as an admixture were both found to satisfy quality requirements.
Compressive strength of cores sampled from a full-scale model specimen of high-strength concrete, placed under normal temperature conditions, were compared with those obtained from the estimated temperature curing. A temperature history under low temperature conditions was estimated from the measured data, which was then applied to specimens subjected to the estimated temperature history in a thermostatic chamber. Compressive strength of the specimens were then compared with those of cores sampled from a structure built in the winter. Reproducibility and effectiveness of the estimated temperature history curing method was thus confirmed in experiments.
The concrete ground work often causes some troubles on the floor, because of a low quality of the concrete. As one of these backgrounds, it is enumerated to lack the evaluation method for the flatness, the surface strength and the moisture content that are important qualities for concrete ground work. So this study presents the rapid measuring methods, the evaluation methods and the draft of four stages grading using 2 m straightedge, the scratch tester, the humidity test paper and the moisture meter.
In order to know the seasonal variations of compressive strengths of ready-mixed concrete, test data on 7 day and 28 day standard cured compressive strengths of ready-mixed concrete obtained in three years from Jan. 1999 to Dec. 2001, were analyzed and discussed comparing with the past data in the literature. Concretes were made of Normal Portland cement and Type B Portland blast-furnace slag cement. The data indicated specified design strength increased linearly, the rate of increment being 1 N/mm^2 in 5 years. Standard cured compressive strengths affected with seasonal was remarkable ; standard cured compressive strengths at 28 days were 1.25 times of Nominal strength in summer, and 1.5 times in winter. The reductions in strengths in summer are considered to be affected with the increase of water content to compensate slump loss.
The life span of external insulation building which is related to the speed of concrete's neutralization has connection with the air permeability of external insulation method. This study generally measures the air permeability of external insulation method, and examines the restraint effect of neutralization in external insulation method from the accelerating test of concrete's neutralization. In addition, it described the relations between the air permeability of external insulation method and the restraint effect of neutralization.
The characteristics of wind pressures acting on a circular flat roof have been investigated, based on the data obtained from a wind tunnel experiment. A simple model of the pressure field is provided as a function of the geometric parameters of the building as well as of the turbulence parameters of the approach flow. A discussion is made of the application of the pressure field model to the wind load estimation, based on the gust effect factor approach and the LRC method. The gust effect factor and the equivalent static load distribution derived from the pressure field model are compared with those obtained from the time history of the pressures. The results indicate the validity of the pressure model.
The aim of this study is to find the minimum requirement of overturning moment capacity of rigid buildings due to real earthquakes. A two dimensional rectangular building model which is founded on elasto-plastic springs are analyzed against real earthquakes considering geometric non-linearity, so called P-Δ effect. The minimum uplift and subsidence strengths of the foundation springs which may not cause overturn collapse are obtained for several models with different aspect ratio. It is clarified that the minimum requirement of overturning moment capacity is determined by the subsidence ultimate strength than up-lift one, and this is approximately given by a simple formula derived from energy equation.
The high performance of seismically isolated structures during the 1995 Kobe earthquake revealed that seismic isolation systems are very effective on keeping the safety and functions of buildings during major earthquakes. In case of houses, it is generally difficult to elongate the period of the system to the sufficiently effective period by ordinary laminated rubber bearing isolators because of their light weight. In addition to rubber bearings, development and application of sliding and rolling isolators are needed for houses. In this paper, the mechanical characteristics of various kinds of seismic isolators newly developed and the effects on the response of seismically isolated houses are discussed by the shaking table tests of seismically isolated house models. The seismic performance and the validity of seismically isolated houses during strong earthquakes are demonstrated. It is shown that the seismic response of seismically isolated houses is definitely dependent on the mechanical characteristics of isolators, and that rubber, sliding and rolling isolators have their own distinctive features in the seismic response.
Damage indexes are defined as physical values that can be well correlated to a critical damage in a device or a structure. A new sensor that can memorize such damage indexes is proposed. The mechanism to memorize the indexes relies on the pure plastic deformation of the sensing section. The pure plastic deformation is made possible by introducing a thin wire that is easily buckled by a small compressive force. In addition, the damage indexes can be retrieved wirelessly if desired. Introduction of LC oscillator into the sensor enabled wireless reading of the indexes. Power supply to the LC oscillator is achieved by an electromagnetic induction system. Theoretical and experimental studies are presented to show excellent performance of the proposed sensor.
In this paper, we are introducing a design method concerned with the shifting of shear force between twin-tower buildings. The twin-tower buildings, a base isolation retrofit structure, had been originally built separately. One is rectangular shaped and the other is L-shaped. In this project, they are base isolated and joined at foundation level. Since the upper buildings are different shapes, they vibrate randomly. Consequantly, an enormous shear force will be caused at the connecting part. In this paper we discuss the process of the above mentioned design method that is used to solve the problem.
The effect of a viscous damper on a dynamic response of a single story linear system with a uniaxial eccentricity is investigated. The main results are as follows : if dampers are installed effectively, torsional deflection can be made very small. Furthermore, as a result of examining the applicability of the CQC method, it turns out that the evaluation accuracy of a response is about 10%, when the elastic radius ratio became 1.2 or more. Moreover, the formula that gives the effective amount of arrangement of a damper is proposed.
Twenty years have passed since response control systems, which reduce structural damages caused by earthquakes or strong winds, were used in actual buildings. JSCA conducted a survey of response controlled buildings on design offices and construction companies, and made a database. Based on the database, first, this paper classified the number of the buildings which use response control systems by construction years, purposes of the buildings and types of device mechanisms. And, this paper analyzed the distribution of the applied damping forces, and their response reduction efficiency. Finally, this paper reports the result of this analysis, and discusses the present situation of response control systems in Japan.
This paper studies the strength of buildings designed by the calculation method of response and limit strength. Analyses are based on design study documents submitted to the committee of design investigation in General Building Research Corporation of Japan. The following conclusions were drawn. Consideration of the soil-structure-interaction effects does not have so big influence on strength. However, construction site, where surface-ground amplification is very small, may leads to low strength of buildings.
The purpose of this paper is to clarify the floor rigidity for the structural analysis. First, the ratio of the beam rigidity with floor for that without floor (the extra coefficient) was examined based on the results of finite element analysis of model composed of column, beam and floor. As the result, the extra coefficient in considering the slab effective width provided in the AIJ standard was approximate to that in considering the rigid zone proposed by authors in the end of members. Next, the equation that estimated the extra coefficient was proposed based on the results of calculation in considering proposal rigid zone.
In this study, the performance of non-fixation pile cap processing method using pile cap joint was investigated by using two series of experiments, past construction records and excavations. As the result, it is proved that the performance of pile using this method satisfied the performance requirements for small buildings.
A number of reports have been published on investigation of damage to pile foundation of buildings due to the 1995 Hyogoken-Nambu earthquake. The result of these investigations indicates the urgent need for development of techniques to enable quick and accurate assessment of damage to piles following major earthquakes. Authors have been conducting a series of researches on the development of monitoring techniques to detect damage to concrete piles due to earthquakes. The sensor using carbon fiber has already been proposed, and its applicability has been investigated by various kinds of experiments using PHC piles. In this paper, the examples of installation of the sensor to actual structures are described in detail to investigate the applicability to practical purpose.
The concept of a damage-controlled structure that reduces seismic response is effective to meet the requirement. Here, we applied to Takatsuki roof structure with axial yield hysteretic dampers arranged for flat system truss as a damage-controlled structure, in order to improve seismic performance. As results of response analyses, dampers can well work to keep roof structure within elastic response against large earthquake.
In this paper, the ultimate horizontal resistant force of Japanese wooden houses considering the stiffness of both floor and non-structural walls is discussed. The analytical model has the restoring force characteristic composed of the floor, bracing bearing walls and non-structural plaster board walls. The results may be summarized as follows : The increase of floor stiffness does not make the ultimate horizontal resistant force increased efficiently. The easy calculation method gives the lower limit of the ultimate horizontal resistant force.
This paper focuses on the joints of failure mode in traditional timber structures. These joints have strong influence on the strength and performance of timber buildings. The purpose of this paper is clarify the strength and failure mode of pegged, mortise and tenon joint. Static shear loading test of the joint was operated. The combination of bending, shear and compressive failure of the peg within the joint was observed through the experiment. The deformation of all the members of each phase is documented in detail. The failure model of the joint was found to be similar to that of the bolt joint for double shear connections.
A dual-layered wooden HP-shell was used for the Yamadera Post office. The layers, crossed relative to each other, are constructed of white wood boards connected with lag screws and further reinforced by aramid fiber sheet. Due to the complexity of this construction, the structural characteristics are not obvious. Therefore, the white wood material and the laminated wood panel of the HP shell were tested. The results of these experiments are as follows. 1. The bending performance of a laminated wood panel is equivalent to the performance of the one layer of the directions of an axis. 2. It is possible to increase the shear strength and the rigidity of the laminated wood panel by aramid-fiber reinforcement.
In this paper, we evaluated the effects of vibrational characteristics of slab on void Rahmen structures. Vibraton tests were carried out for the one way void slab for 3 apartment houses in Shizuoka city. The experimental values were compared with the analytical values. On the analysis, we used a beam element model with a vertical spring for the partition walls. As the result, the vibrational characteristics of void slabs with the partition walls are evaluated by the beam element model with a vertical spring.
Reinforced concrete columns subjected to shear and high axial forces typically fail due to the crush of concrete after flexural yielding. In this paper, the design equations for the deformation capacity of these columns, which have been proposed in the authors' previous papers, are examined using the experimental data with a very wide range of structural parameters. It is concluded that the design equations give a lower boundary of experimental data, and that they are useful to predict the deformation capacity of the columns subjected to a varying axial force as well as a constant axial force.
We analuze the structural characteristics of buildings designed by the calculation method of response and limit strength based on design study documents submitted to the committee of design investigation in General Building Research Corporation of Japan. In this paper, the tendency of characteristics was mainly investigated about the maximum story drift angle, natural period, and base shear coefficient at the two limit states. As results of consideration, it becomes clear that base shear coefficients of buildings by the calculation method of response were smaller than those by the conventional design method. In addition, validity to check the true responses of the maximum drift angle and shear coefficient was confirmed.
For the steel structures, semi-rigid connections which permit deformation have studied by many researchers. This is expected that seismic energy is absorbed by the earlier yield of angle members and possibility that seismic response of steel frame are reduced. However many reports are only presented concerned with member test and plane frame analysis so far and these semi-rigid connections are not apply actual design yet. This paper presents allowable stress design method corresponding angle plate and bolt yield earlier than beam.
This paper describes results of the structural investigations on Onoda Bottle Kiln in Yamaguchi, which was constructed with brick masonry in 1883. The fundamental dimensions of the kiln, the material properties of the brick used, the soil conditions under the kiln and the vibration characteristics of the kiln are presented. Furthermore, a lumped-mass system model and a FEM model of the kiln are presented herein, which are to be used for earthquake response analysis and stress analysis to investigate the structural stability of the kiln.
This paper discusses the seismic performance of Onoda Bottle Kiln in Yamaguchi, which was constructed with brick masonry in 1883. The results of the investigation on seismic activity around the located area and the earthquake responses of the kiln obtained from the analysis using the lumped-mass system model representing the dynamic behavior of the kiln are presented. The stress distributions in the wall of the kiln subjected to the equivalent earthquake load are also investigated using FEM analysis, and compared with the strength of the brick masonry.
Loaded fire resistance tests are conducted on five different 1-story tall speciments of Japanese traditional timber frame soil wall construction commonly used for historic townhouses in Kyoto. The test result show good prospect for single-side plastered soil wall commonly used for party walls to be rated as Fire Protective Construction by reasonable improvement and effectiveness of the cedar panel covering on the external wall surface for the improvement of the fire endurance.
Visually handicapped persons can recognize a wall or obstacles in traveling by hearing sense (called obstacle sense). However, they cannot detect small or thin obstacles, these often cause crash accident. In the present work, the development of an acoustic reflector for tapping sound by a white cane, which is attached to above obstacles, is studied. Through the cognition test by the hearing on the acoustic reflector consisting of membranes and a space, it became clear that this reflector developed has sufficient possibility for a practical application.
We carried out the experiments of the influence of some ceilings of the multiple dwelling houses on heavy-weight floor impact sound in the experimental room. This paper mentions the results of the experiment. According to the results, we acquired useful information for the acoustical design of the ceiling of the multiple dwelling houses. For example, the thickness of the air layer between the ceiling and the concrete slab has much influence on heavy-weight floor impact sound level. Furthermore, the interval of the hang bolts of the ceiling also has much influence on that.
School rooms have large window, which size is over one fifth of floor space of the room. But it can be expected that lighting is depend on artificial light in school rooms. In this papers, the actual state of curtain and artificial light use, and the reasons for use of these tools are studied, by means of survey at schools in Hokkaido.
The purpose of this survey is to know the actual conditions during the summer of the residential indoor environment in urban area in China. The apartment houses under investigation were sited in urban area of Changsha, and Beijing. The questionnaire survey and the measurement of indoor temperature and humidity were carried out in the summer of 2002. The questionnaire survey revealed the life style of summer season and the way of use of air-conditioner. The measurement showed that indoor temperature and humidity in Changsha and Beijing were relatively high. In some houses, it was found that the concentrations of formaldehyde and acetaldehyde were relatively high.
Ceiling radiation heating using solar heat system that makes use of hot water produced in a solar heat collector, kept in a heat storage tank and sent to ceiling radiation panels above a living room. Tests have been conducted not only on ceiling radiation heating but also on the joint heating with floor heating and heating by a conditioner, as the heating capacity of ceiling radiation heating dependent solely on solar heat was insufficient. The authors have obtained information on assessment of comfortableness of ceiling radiation heating by residents in an experimental house through a questionnaire.
The cross comparison of CFD results of flowfield around a building model with 4 : 4 : 1 shape using various k-ε models were carried out, in order to assess the accuracy of CFD prediction of flow around a high-rise building including the velocity distribution at pedestrian level. The results of the analyses were compared with the experimental data under the same computational conditions.
The evaluation of outgassing emission rate from cleanroom construction materials is an important technology to control the concentration of airborne molecular contaminants in the clean room air. The CR-ADPAC system (Clean Room-ADvanced Pollution and Air quality Chamber system) was developed to evaluate the outgassing emission rate in consideration of an actual cleanroom for electronic device fabrication. The CR-ADPAC system is consisted of a small stainless steel chamber equipped with an inner circulation fan and purified air supply unit which supplies humidified controlled air. It is able to control temperature, humidity, ventilation rate and the air velocity on the surface of test piece. The measurements of outgassing emission rates from sealants were performed using the CR-ADPAC. It was clarified that the air velocity on the surface of test piece influenced remarkably on the outgassing emission rate.
VOC concentration measurement in 6 hospitals was conducted in order to obtain information on the IAQ, using passive samplers. Almost all of toluene, xlen, ethelbenzene and styrene concentrations obtained from 158 points were lower than the trace. Concentrations of the formaldehyde and toluene measured at each point exceeded the their guideline values and those of xlene obtained from 2points also exceeded it's guideline value. TVOC concentrations obtained from 53 points out of 55 were lower than the detective limit, 200μg/m^3.
Experiments on ventilation efficiency were performed using a test house in summer. In this system, outdoor air supplied from the crawl space goes through inner space of the walls to the attic space. The air of inner space of the walls is supplied to room through air inlets between inner space of the walls and rooms. The parameter of experiments is number of the air inlets. As the result of experiments by step-down and step-up method, it was found that the outdoor air reached to the rooms as expected and the air inlet is useful for supplying the air.
Since beginning of 1990's, environmental assessment methods have been developed and implemented in many countries to enhance energy conservation building, green building and high performance building. Meanwhile, some environmental assessment methods and tools have not been used practically for its difficulties, and loss of time and cost. The purpose of this study is to develop a simplified assessment tool on a web site and to implement assessment, to know the possibility whether it works or not in practical. Major goal of developing web based assessment tool is to increase the awareness of designer, engineer and building owner about building environmental assessment tool and green building.
This study targets on a challenge to build some sort of de facto standard program for design training class in a university where the environmental conscious concept aiming sustainable design is strongly emphasized. MCDM, developed in the circle of TEA SHCP Task 23, is embedded in the program to support students' decision-making process. This paper reports on our first step. A field survey, where students studying architecture and professors in a certain university are involved as samples, was conducted shedding some light on how to apply MCDM in case of selecting process for dwellings. The result implies, for example, that there is a difference on how important among decision-making criteria depending upon how to be inquired.
We held a workshop of Klimaatlas on 10th September 2002 in Kitakyushu. This workshop was held for examinations of making process of the climate analysis map and the recommendation map based on climate analysis data. These maps were overlaid by ones using geographical information system. Through three sub-committee meetings, the climate analysis maps and the recommendation maps at Kokura, Kurosaki and Orio were made using aerial photograph, land use data, altitude data, weather survey data and city planning data. After that, the examined results were presented and future problems for applying Klimaatlas to building/city planning were cleared.
A simplified calculation method of resource and energy consumption, and CO_2 emission is proposed. These intensities are based on 1995 input/output table in Japan. This method is applied to sample buildings. The results of material consumption calculated by this simplified method and detailed method are almost in substantial agreement in one of the buildings, and disagreement in the other. The reason is that the consumption of temporally road construction of sample building is different from that of intensity calculation. The resource consumption in structure work is 80% of total consumption and in mechanical and electrical work is only 7% of total consumption.
Energy consumption of apparatuses and thermal environment were measured in an all-electrified house in Sendai, and energy consumption characteristics of some apparatuses was clarified. Numerical simulation with the programs "SCHEDULE" and "TRNSYS" was carried out. The accuracy of the numerical simulation model was verified by comparing with a measurement result. Furthermore, the energy saving effect by change of a life style was examined using the model. It was found that about 20% of the total amount of energy consumption could be cut down by change of a life style.
In northeast China, a master bedroom is used variously, and various furniture has set in the master bedroom. In recent years, the area of a residence increases and living room is also large in connection with it. On the other hand, there is little change of the area of a bedroom, is the size which can set various furniture. A bedroom is used when receiving the customers in the good friend of relations. Thus, the bedroom is properly used by the merit of a visitor's relations, and the time zone. In northeast China, it is important to take that space is used for multiple purposes into consideration, when considering the life style of future northern countries.
A physically handicapped child is in the tendency for the action range to be restrained and for a going-out opportunity to decrease. If a spread of a life of a physically handicapped child and family, it will be thought that the home which took in outside environment is required. Then, in this study, while clarifying the life actual condition in a sitting-room which a physically handicapped child passes for a long time except for sleeping hours, a care attendants consciousness to viewing from a physically handicapped child's room or outdoor space around the house is grasped, and it aims at exploring the state of the residence of the future physically handicapped child which took in outside environment.