This research examined air-permeability of concrete mock test piece uses various kinds of binding material. The parameter of the experiment was various kinds of binding material, water binding material ratio, and an age of demold. When the water-cement ratio is small and the hydration is slow, the air-permeability is small. Influence of the age of demold was admitted only by the rapid air-permeation speed. The relation between the depth of neutralization and the air-permeability coefficient was able respectively to be shown by Portland cement, Portland blast-furnace slag cement, and Portland fly-ash cement in one line. However, coefficients of determination were smaller than the researches in the past.
Portland cement production dominates a major part of CO2 emission generated from construction materials and its reduction in terms of concrete is of particular significance. As a technical solution, the authors have been developing an HS concrete with a granulated blast furnace slag content as high as 65 percent for underground mass concrete constructions. In this paper, aiming at wider dissemination of massive HS concrete, the standard correction values of concrete compressive strength in structure (28SM91 value) were verified. The correction values of concrete strength in structure 28SM91 is 3N/mm2 through all season examined by statistics study.
The aim of this study is to experimentally investigate shrinkage properties of blast-furnace slag blended cement concrete (BLS-concrete, hereafter). For this purpose, restraint cracking tests for concrete were conducted at three ambient temperatures, 10 °C, 20 °C and 30 °C. The experiments showed that shrinkage cracking resistance of BLS-concrete was better than normal concrete regardless of ambient temperatures, and BLS-concrete had the same concrete strength development as normal concrete.
We previously reported on the required mechanical characteristics and a deformation evaluation method for thermal insulators used in floor slabs directly above footing beams, and for formworks composed of extruded polystyrene foam that don’t require removal. In the present study, bending and bearing pressure experiments were conducted on a component specimen, focusing on (1) the bending stiffness of the formwork when the polystyrene foam extrusion direction is perpendicular to the formwork bearing span, and (2) the bearing stiffness against a square pipe used as a joist member. Moreover, a full-scale experiment was conducted using loads equivalent to those during actual construction, and it was confirmed that the foam formwork deformation during construction can be assessed based on the stiffness obtained from the component experiment. In this paper, the scope of the evaluation of foam formworks in the previous report is expanded based on the results of these experiments.
In this study, influence of revibrating conditions on bond strength by changing diameter of steel bar were investigated. Parameters included diameter of steel bar, timing of revibration, duration of revibration and duration of contact between steel bar and internal vibrator. As a result, bond strength showed a decrease when diameter of steel bar is larger. And the influence of revibration and contact between steel bar and internal vibrator showed an increase when diameter of steel bar is smaller. This paper also proposed an appropriate method of revibration including difference diameter of steel bar.
Exterior wall tiling using organic adhesives is expected to prevent tiles from separation because of its high elasticity, but generally mortar with poor elasticity has been used to smoothen irregularities of the concrete surface. We have developed an organic surface preparation material with higher elasticity than mortar, so that the tile layer could consist of all elastic materials. Various tests were carried out to evaluate mechanical properties and durability of the surface preparation material and the tiles adhered using this method. Test results showed that the material had enough strength and elasticity to meet JIS A 5557 criterion value. Test results also proved that the tiling had adequate deformational and fatigue property to improve the separation prevention performance.
The weatherability evaluation with outdoor exposure test for building exterior materials is the most essential. The most standard outdoor exposure test site throughout the world is considered to be South Florida, US. Also the accelerated weathering test that gathers plenty of sunlight in dry condition is carried out in Arizona. The investigation into the actual conditions of these sites was held. The actual conditions of the tests and weather conditions in both sites have been grasped. Furthermore, outdoor exposure tests in Florida and Miyako Island, Japan had been carried out. All evaluated powder coating had been more notably deteriorated in Miyako than in Florida.
In this research, the applicability to the concrete of the echo chip was examined in the beginning. The content was examination of difference, influence of direction of measurement, and influence depth. The following examination is a method of presuming compressive strength from Equotip hardness value. The method of the estimate of compressive strength was requested from the relation between Equotip hardness value of flat test piece and compressive strength of cylinder test piece.
In recent years, it is necessary to secure the non-structural material in the event of a disaster. Lathing plaster ceiling of the traditional building is no exception. It is necessary to a healthy degree to properly evaluate respect for the value of such as culture, history, design, technology and authenticity of the traditional building. In this study, we have developed the repair method of existing ceiling by the acrylic resin. This technique does not require traditional skills. Therefore, to improve the health of the building at a low cost, it is possible to protect the history, culture, technology and safety.
This report examined torsional response of a seismically isolated building on inclined bedrock using strong motion records. Ground motions increases the amplitude and produces time lag to propagate in according to a layer thickness of the surface ground. We also evaluate the torsional response using ratio of it. In result, torsional response of floor on seismically isolated layer is reduced to half by effect of it in comparison with basement.
Variation of 1st natural frequency of super high-rise residential buildings were investigated by using strong motion records during the 2011 off the Pacific Coast of Tohoku earthquake and ambient vibration records. Non-linear characteristics of two SRC buildings were similar to other super high-rise residential buildings. Based on analysis using intermediate floor records, inter-story stiffness at the lower layer has decreased from the increase of modal amplitude ratio of the middle floor to the top floor. Possibility for height-wise damage estimation is presented by performing microtremor measurements at plural floors.
This paper addresses the developing of response reduction device of a detached house during earthquake. Reduction devices are composed of shear key and improved composite soil material, which are arranged between the seismic-isolated layers. The mechanical properties of the improved composite soil material are investigated by laboratory tests. Then we confirm the hysteresis characteristics of this system by shaking table tests. Furthermore we investigate the response reduction effects of a house with this device during earthquake by analytical studies.
In shake table experiments of structures, a lot of accelerometers are generally used to identify structural response while only a few displacement transducers are installed because large stiff frames are generally needed to measure displacement. Theoretically, displacement can be calculated from integrations of acceleration. However, low frequency components of measurement errors, noise and drift components resulted from permanent drift are amplified and unrealistic large displacement can be observed. To reduce low frequency errors, low-cut-filters are empirically used. This report discusses about errors of measured displacement and evaluates accuracy of the displacement resulted from integration of measured acceleration.
The standard requires seismic design of specified ceilings under linear response of main frames caused by occasional earthquake motion. But it is preferable to check safety under non-linear response of main frames caused by rare earthquake motion. In this paper, a direct estimation method for non-linear floor response spectrum is proposed. The method is adapted one of linear modal analysis, composed of empirical formulas of non-linear response. By comparing seismic design forces for specified ceilings with those caused by rare earthquake motion, it is shown that specified ceilings with high natural frequency can avoid damage even under severe earthquakes.
In this paper, we present the experimental results of a series of microtremor measurements of a RC building during demolition work (reduction process) in order to clarify their properties in dynamics. The RC building was reduced from 5 stories + 1 story penthouse to 4 stories. We conducted microtremor measurements before, during and after reduction process. Natural frequencies of the RC building were increased in accordance with its reduction process and strengthening works. Based on the equivalent single degree of freedom system, influence of weight reduction and stiffness increment on natural frequencies by reduction process and seismic strengthening is clarified.
Method to investigate the vibration characteristics of building by sequential two-point measurement of microtremor is proposed. The purpose of this method is to reduce the measurement cost compared to the conventional simultaneous measurement. By taking several patterns of two-point microtremor measurement and multiplying each transfer function, the elevational vibration mode is derived. By using the rotational spectrum of two-point on the same floor the rotational vibration mode is identified. Microtremor measurement is carried out on 9-storied office building in Yokohama, and the proposed method is verified to obtain the same result as conventional simultaneous measurement.
Static load increment analyses were carried out for the investigation of the cause that the damage of piles occurred in Chiba prefecture during the 2011 off the Pacific Coast of Tohoku Earthquake. Results similar to the real damage was obtained, using an analysis models considering the nonlinearity of piles, pile head connections and soil springs and assuming progress of graded destruction and distribution of axial loads.
The roof of the Teshima Art Museum’s main building in Teshima, Kagawa Prefecture, is a reinforced concrete shell with a freeform curved surface in the shape of a water droplet, having a maximum span of 41.2m, a maximum rise 5.12m and thickness of 250mm. This paper discusses the structural planning, design and construction methods for implementing such shallow, thin RC shells with freeform curved surfaces. Especially, we described in detail about the building summary, the form-finding of shells by computational morphogenesis and the policy of structural design.
This paper describes a new developed wooden sliding panel wall inserted in wooden frame. In-plane shear tests for two types of these panel walls were carried out compared with the typical plywood sheathed wall. The main results are as follows. The rigidity and strength of the new developed walls are about 20% and 50% of those of contemporary bearing walls under the horizontal deformation of 0.05 rad. Although, beyond this deformation, the rigidity and strength of new developed walls gradually improve and withstand large load.
An influence of edge bonding between laminae, edge gaps between laminae without edge bonding, and edge distance from LSB to egde of a lamina, on pull-out properties of LSB joint embedded into CLT parallel to the grain direction was investigated and confirmed following characteristics. 1. Edge bonding was no effect on pull-out properties. 2. Pull-out properties of LSB embedded into a gap decreased with increasing width of the gap. 3. The edge distance was no effect on pull-out properties, if it is more than 0.7 times of a top thread diameter of LSB or the gaps is below 0.5 mm.
To estimate the Young’s modulus or internal defects of wood with a non-destructive test using an ultrasonic velocity, the factors contributing the velocity need revealing. The detailed distributions of the ultrasonic velocity, measured with a measuring instrument and particular pointed sensors, show as follows: Of the three directions of wood grain, the ultrasonic velocities increase in the order tangential, radial, longitudinal directions. In the longitudinal direction, the velocity around the pith is slower remarkably. A slit between two sensors extends the transmission path, and thus slows the ultrasonic velocity.
This paper describes the results of the structural survey on wooden traditional row houses in Kyoto including vacant houses. Through the investigation, the structural features including the seismic performance of the row houses were revealed. We analyzed the influence when only one house of the same row house was demolished or reinforced. Finally, we investigated the differences in transition of temperature and humidity between the occupied house and the vacant house of the same row house.
We studied and developed 9 meters to 12 meters span wooden king-post trusses and others using circulated timber and pre-cut system for framework of wooden house, which can be adapted in low rise buildings such as school buildings and so on. Upon developing, we had conducted full-scale static loading test and grasped the characteristics of those. In 2015, a revised edition of JIS A 3301-2015 (Design standards for wooden construction of school buildings), adopting these trusses, was released.
Wooden trusses are effective method for constructing long span beams using standard size timber for residential use which is under six meters long. In this research, in order to create the standard drawings, the full-size bending test of parallel chord truss which took up three tree wood and was consisted by typical metal fittings and joints that can be produced by pre-cut system was carried out. As the results, it indicated structural property of each wood species and calculation formula to estimate the yield strength and the rigidity was established.
We conducted tension and shearing tests on lath and plaster ceiling in order to reveal the structural mechanism about the adhesion of plaster to wooden laths. In addition, we developed a mechanical model and a structural design formula for lath and plaster ceiling. Through the tests, it was found that whether plaster is pushed out to the rear of wooden laths or not, has the most important influence on the adhesion of plaster. We could develop the formula to accurately evaluate the strength of lath and plaster ceiling.
In order to reduce the time and labor in damage investigation, post-earthquake damage evaluation method in real time for RC buildings using observed ground motion and building response is proposed. First, capacity spectrum of the building is adjusted according to observed acceleration response records since the capacity spectrum using only current analytical method is not always accurate. Adjusted capacity spectrum not only can estimate the building response at the time of earthquake, but also can estimate response for larger earthquake that the building has not experienced. Then based on the estimated response and adjusted analysis model, the damage level and residual seismic capacity are determined and post-earthquake damage is evaluated. The proposed evaluation could estimate accurately the damage level. However, the accuracy decreases at the point just between the borders of damage level.
This report verified the bond splitting strength of lap splice of concrete beams using reinforcing bar and metal grid. Cyclic loading test was carried out on 5 specimens in which all reinforcement were spliced at the same section. The variables of specimens of metal grid were four kinds of different types of thickness and shapes, such as expanded metal grid and square metal grid. Measurements were the maximum crack width and ultimate cracking pattern and failure mode of splices. From this investigation, it became clear that the bond splitting strength of concrete beams using metal grid fell compared using reinforcing bar.
The buckling-restrained braces using the steel mortal planks (BRBSM) is applied to reinforced concrete structure (RC structure). In general, it is difficult to design and construction for buildings that integrated RC structure with the buckling-restrained braces. Therefore, in this paper, we report the anchor-less structural system using bedplates and wedges. Structural performance of this system is confirmed by the experiments using specimens of low strength type and high strength type. According to the tests, the effectiveness of this system is verified. However, the improvement of the steel frame is necessary to more follow for the deformation of the RC structure.
After 2016 Kumamoto Earthquake, we investigated 80 two-storied damaged houses of light-gauge steel structure by microtremor measurement and visual check. We analyzed the relationship of natural frequency of the houses by microtremor measurement and average displacement response spectrum (0.2 - 0.3 seconds) of construction area. As a result, natural frequency of the houses decrease as the displacement response spectrum increase.
This study proposed a construction management system, which is based on in-situ measurement method using ensemble averaging (EA method), for examining whether the constructed interior materials perform expected absorption performance. First, the reproducibility of the system was confirmed through the round robin test, in which the absorption characteristics of commonly-used single-layer materials were measured in three different rooms. Then, an experimental study on more complicated multi-layer materials revealed that the system is measurable the difference of absorption characteristics due to the slight difference of structure in materials. Finally, the system was applied to the development phase of materials, and the availability was demonstrated.
This research examined measuring method by questionnaire survey with presenting a hypothetical measurement example of vibration induced by traffic vibration in room. Results obtained by the survey were the followings. (1) For the measurement of magnitude of the vibration, basically use of traffic vibration source. However, in order to compare after other buildings and measures, it was found that the input is used together with known vibration source. (2) For the measurement of magnitude of vibration, many respondents select the center of the room and the middle of floor surrounded by large or small beams.
Through the opportunity to plan lighting for platform of a train station, this research aims to determine the requirements and design a new LED globe light to meet it. In order to increase brightness where there is no wall or roof, as well as gaining flour brightness, sandblasted globe was attached to LED spot light. Considering the public nature of the station, design code was driven from images of the region. Practical utility such as no light pollution and decrease in energy usage were verified.
In magnetic shielding with the opening of the magnetic material around the electric power line, I confirmed the difference of effect in various opening conditions by an experiment. The results are as follows. The shielding effect was low under conditions of opening rate more than 30%. The difference by opening pattern was small, but the effect with the staggered pattern was high in a specific condition. By the method to increase area of each opening, the effect decreased in the neighborhood of the power line, but there was not the difference in the distant place.
In previous studies, we developed a phase-change material (PCM) plastered wall, which is a novel finishing material with high thermal storage capacity. The PCM-plastered wall exhibited significant improvements in indoor environments and energy saving through an experimental module. This paper presents measurement results of tests conducted to determine the physical property of the PCM plastered wall under several Japanese Industrial Standards (JIS). The workability of the PCM plastered wall was evaluated using our subjective test to encourage the widespread use of PCM microencapsulated building thermal storage materials.
In this study an ability to improve thermal insulation properties of steel shutters installed at factories was considered. At the first stage heat transmission coefficient of a steel shutter with inward air layer constructed using thin vinyl sheet, were calculated with measured data of air temperatures in and around a steel storeroom and amount of heat flow. And also the effect of inward air layer to prevent the dew condensation on metal components’ surfaces in a factory was verified with measured data of winter thermal environment.
“ENEMANE HOUSE 2015” was held as a part of business for promotion in Zero Energy Houses (ZEH). Waseda University collaborated with enterprises and proposed “WASEDA LIVE HOUSE”. A real size WASEDA LIVE HOUSE was built in Yokohama and its environmental performance was measured for seven days starting October 23rd to 29th 2015. This paper shows design of WASEDA LIVE HOUSE and result of its operation.
This paper discusses about an examination on adequate capacity for multi-sprit type air conditioner using centralized controller with a function of gas rate proportional division. The objective system is a gas heat pump air-conditioner of an agricultural research building. The effect of energy saving was analyzed by LCEM tool using the estimated actual thermal load under the assumption of retrofit / renewal for air-conditioning equipment. The energy savings from the current situation was that the case of proper capacity repair is 5% reduction, and the case of renewal can be reduced 15% of the operation energy consumption.
It is important to effectively utilize the waste heat from the electric generator in order to achieve high overall energy efficiency of cogeneration system (CGS). To examine the energy conservation efficiency of CGS on the actual situation, we have researched the operative situation of the PAFC-CGS that has been installed in the new building in the university. As a result, the primary energy consumption of the building was found to be 52.8% less compared to the benchmarks of DECC. And the annual average of the thermal efficiency of the PAFC-CGS was found to be 0.54.
We compared the energy simulations of a Zero Energy Office Building (ZEB) at the design stage to its energy consumption during operation. The ZEB was located near San Francisco, California. This comparison was difficult because simulations used different categories than energy data collected through sub-metering. Overall, actual net energy was higher than simulation by 47%, while actual HVAC & lighting energy use were lower than simulation by 34% and 26% respectively. Actual plug energy use was more than 800% higher than simulations. Water heating energy disappeared as a separate end use because decentralized, plug-in units replaced a central unit.
This paper focused on the effects of outdoor temperature upon the fatigue due to temperature changing in the urban area. We conducted the questionnaire survey at Osaka Prefecture in 2010 through the winter from summer. As a result, a positive correlation to fatigue against outdoor temperature in summer and the negative one in winter were found. And the statistical significance were found in the score of DCF between the case of using air conditioner and not.
PIV is an attractive experimental method for investigating turbulent flow around building model in a wind tunnel. However, it is difficult to obtain data with high accuracy in large size wind tunnel. In this paper, first we give an overview of PIV technique and organize the experimental conditions of past PIV in urban climatology. Then, we consider a technological problem which is called peak locking. We explain the mechanism of the generation of peak locking and how it affects the final output. Avoiding peak locking is difficult in general experimental condition, but it is mitigated by a simple image processing.
In recent years, as the need for development of low-carbon architecture increases, practical use of the natural energy that surrounds buildings is attracting attention. Heat/cool trench systems make use of one such natural energy, subterranean heat. These systems reduce the fresh air load by introducing outside air through trench that pass beneath the bottom floor-slab before blowing the air indoors. This study involves a year-round measurement survey of outside air and indoor outlet temperature and humidity at school building. The effectiveness of using subterranean heat in a building is examined by calculating heat extraction in summer and heat addition in winter.
In this study, several energy retrofit subsidy systems offered by local governments in Japan are investigated. Using the results, subsidy systems are classified into retrofit techniques, number of subsidies for each technique and subsidy rates. Moreover, energy conservation performance of each retrofit technique is analysed using a computer program for calculating home primary energy consumption. The effects of the combinations of energy retrofit techniques, such as ceiling insulation, LED and latent heat recovery gas water heaters, which are selected from the view point of both energy conservation performance and subsidy performance, are shown.
In this study, totally 370 design data of newly built timber houses in Shikoku, which has been obtained from FY2013 to FY2015, is analysed on estimating energy consumption, energy reduction rate and employing rate of elemental technologies using LEHVES design process such as heat control technology of building envelopes and energy-efficient equipment technology. 265 design data has been obtained in Zone 6, which is called mild climate region, of the Energy Saving standard and 105 data has been obtained in Zone 7, which is called hot humid climate region. Moreover, 50 existing houses’ data, built in mild climate region, is evaluated to compare the differences with newly built houses.
The authors have researched hot air floor heating system with a wood pellet fan-heater. This paper describes its space heating effects of the first house with the system. Indoor vertical temperature difference was less than 1.5°C except the date with outside air temperature below 0°C. The globe temperature in the living room varied from 15°C to 25°C within the range of comfort globe temperature and that in the second floor’s room 11°C to 22°C. Temperatures of the lower surface of wooden floor surrounding the hot air outlet were kept below 43.1°C.
In a series of studies regarding failures and troubles (F/T) in 6 hospitals, the contents of F/T and the repair were presented targeting on the air-conditioning-systems, the sanitary systems, the electric systems and the building elements. This study gives results of the security systems, the fire protection systems, the manlifts and the container vehicles to cover our studies. This report shows the total number of F/T and the number of each device. In addition, the mean time to repair of each system and its detail which repair was prolonged are presented. These results give information regarding operation plan for maintenance workers and reliability of the subject systems.
This paper reports the results of a field survey on the indoor air temperature and relative humidity environments of a traditional courtyard house in Old Delhi and a modern apartment in Gurgaon, India, in winter, summer and monsoon. The modern apartment showed more suitable indoor temperature than the traditional courtyard house though its heat loss was not negligible under cooling conditions. The traditional courtyard house had quite stable indoor temperature because of the large heat capacity from thick brick walls. The courtyards worked as buffer zone between the outside environment and the mild interior temperature.
Japan Building Maintenance Association has recommended use of the questionnaire sheet for evaluation of cleanness. However, about half of building maintenance companies use self-developed questionnaire sheets. Therefore, a better inspection system is expected for quality control of janitor service as a whole. In the present study, qualified inspectors and monitors participated the field survey to evaluate cleanness of the buildings using three questionnaire sheets. The important items for each location such as an entrance and a restroom were then chosen among many items and a close relation of total scores of cleanness to number of years since construction was found.
“Silver Sheared Living (SSL)” is one of the new choices of the dwellings at home for the independent old man who wants to continue living individually in his local community with his friends. SSL is located on the centre of private house and elderly apartment house. On this study, the ideal images, the problems for realization and the importance as a dwelling of SSL were defined through the workshops with the old men and women. For elderly people that want both to save their privacies and to hinder the isolations, SSL has the possibilities as the elderly houses after this.
The purpose of this study is to grasp the local development of the nongovernment apartment houses supplies on the early stage in Tokyo area after the war. The sources of information for the analysis are advertisements of real estate on Asahi newspaper morning (Tokyo) (1952-1973). The analysis by locations and times proved that the local development was dynamic as follows. 1) The rental apartment houses supply went ahead earlier than the condominiums supply. 2) Later, the condominiums supply passed and spread throughout Tokyo area. 3) The high level technical and architectural attempts were proposed.