The purpose of this study is to reveal conditional mixproportions of concrete for fluidity and segregation resistance. Therefore, we organized changes in conditional mixproportion of JASS 5. In addition, this paper showed preparation conditions such as unit cement content, unit water content, etc., for each target slump and target slump flow by literature surveys.
We have developed a method to reuse those used tiles using acid. In this method, we remove mortar from the tiles by dissolving mortar itself with acid. In this paper we report on three contents. The first is the test result of measuring the adhesion durability of the tiles reused by our method. The second is another test result of assessing our method through reproducing the used tiles that came from actual buildings. The third is an introduction of a case of which our method was applied to the construction project in Hokkaido.
Japanese traditional clay wall on bamboo lathing was investigated that damaged by Kamishiro fault earthquake in Nagano prefecture on November 22, 2014. We confirmed damage states and revealed materials, plastering methods and the lath configurations of the clay wall. As a result, the resistance mechanism against the earthquake was confirmed. Causes of the delamination of the front and back sides of the clay wall layers were revealed; without gaps between bamboo lath and timber framework, falling batten or bamboo lath from timber framework, and with weakness of the sticking force of clay wall layers.
Rigidity of joint with timber structure can be weakened because of the poor accuracy in its installation and the occurrence of backlash with the joint metal due to the timber shrinkage which is a property that material of timber materials have. In addition, due to the nature of natural timber, the mechanical properties of the joint are unclear which makes the mechanical analysis of the timber structure more complicated. In order to solve this problem, direct jointing method which applies adhesive to connect timber parts and joint metal is developed. However, such jointing method does not allow timber parts to be disassembled, same as the reinforced concrete construction. In this report, we propose connection method that provides high-intensity and can be disassembled even when using adhesive in order to enable the reuse of timber materials from the viewpoint of the environment. We also examine mechanical characteristics and confirm that it is feasible.
Polyurethane waterproofing membrane is constructed at the building site by applying liquid material to substrate. Therefore, the performance of waterproofing membrane depends on the quality of construction. In this study, we firstly indicated the way of thinking on process management methods on polyurethane waterproofing membrane, and secondly the experiment was conducted to verify how much process management methods have influence on its performance. Finally, effect of process management methods and problems to be solved were pointed out in conclusion.
In the Great East Japan Earthquake, many large-scale partition walls made of stacked ALC(AAC) panels were damaged. Those walls are constructed with intermediate sub-beams. Strong motion observations and shaking table tests by authors clarified that large vibrations in out-of-plane direction can occur in those walls during earthquakes. A countermeasure to suppress vibrations is to select stiff members enough to keep high frequencies. In the previous paper, a practical selection method of structural sub-members as in a tabular form was proposed. In this paper, validations of the proposed selection method are discussed by comparing the results by FEM.
In February 2014, some large-scale buildings around Tokyo were collapsed or damaged by heavy snow. For light-snow region, using amount of rainfall instead of ground snow depth is recommended to estimate ground snow weight. However, wind influences the amount of rainfall caught by gauges. In this paper, three factors are reported. 1) Survey of conditions at weather observation stations. 2) Analysis of difference between AIJ Recommendations for Loads on Buildings and this survey on conditions of estimating wind speed. 3) Estimation ground snow depth and weight based on this survey. Through this survey, strong effect of wind speed is elucidated.
A study of aging effects on natural rubber bearing that was installed in a seismically isolated building about 30 years ago was conducted. The dynamic properties of natural rubber bearing, physical properties and chemical properties of rubber were examined and there were no significant changes compared with original properties. The creep deformation of the natural rubber bearing was also measured. It was confirmed that creep deformation corresponded precisely to the prediction formula. It was assumed that aging doesn’t lead to any significant change of the rubber bearing characteristics.
The 2011 off the pacific coast of Tohoku earthquake and the 2016 Kumamoto earthquake shook many automated storage and retrieval systems and caused palletized goods to fall down from the storage racks. The authors have developed a seismic isolation system in the direction of rack opening for automatic warehouse to prevent goods falling. In this study, shaking table tests were conducted to evaluate a seismic isolation system using inclined rail bearings. As a result, it has been demonstrated that the newly developed seismic isolation system is effective in preventing stored goods from falling down from rack shelves.
In this paper, we conducted simulation analyses of collision experiments on retaining wall of base-isolated building model using the simple modeling method for lateral resistance of retaining wall with backfill proposed by us. As the result, although the number of collision was evaluated more and the displacement of the seismic isolation layer was a little different, the acceleration response value at the collision to the retaining wall by analysis was relatively well corresponded to the experiment result, and the effectiveness of the simple modeling method could be shown.
The purpose of this paper is to carry out a response evaluation of passive control structure with viscous dampers considering its performance decrement under long-period ground motion. An analytical model of the viscous damper that considered the performance decrement caused by long-period cyclic loading was proposed in this paper, and its accuracy was confirmed by comparing with test results. The time history response analysis using 20-storey model with the proposed viscous dampers was performed. It was verified that the response of the passive control structure with viscous dampers increases under some long-period ground motions.
Hanging type cable rack system partially had serious damage during the Tohoku-oki Earthquake, March 11, 2011. The objective of this paper is to understand the seismic performance of the cable rack system and to propose passive control scheme for the system. Monotonic loading tests of the cable rack and shake table tests of hanged cable rack are conducted. Performance of the specimens is discussed by referring to maximum deformations, displacements, absolute accelerations, relationships of damper force and damper deformation.
Structural health monitoring is a method of estimating the presence of the damage of the structure, and its position and degree by the change of static and dynamic characteristics before and after the secular change or the action of external force. However, the static and dynamic characteristics of the actual structural fluctuate on daily, seasonal and diachronic variations basis without depending on damage or not. These characteristics of reinforced concrete lighthouse were observed for about one and a half year by the authors. This paper presents long-term variations of crack widths, inclination angles, temperatures and natural frequencies of this lighthouse.
This report describes simulation and evaluation of long-period ground motions in the Kanto plain using the two source models, i.e., the SMGA and SPGA models, for the 2011 Tohoku earthquake. The two source models are validated by comparison with recorded motions using the 3D finite difference method. Amplitude level of long-period ground motions in the Kanto plain are discussed by using a hypothetical source model assuming that rupture of the 4 SPGAs off Miyagi Prefecture occur at off Ibaraki Prefecture, resulting in larger long-period components between 2.5 to 4 s than those estimated in the previous studies.
The purpose of this paper is to propose the evaluation curve of human senses to seismic vibration based on subject experiments. In this study, following results are obtained. 1) More than 50% of people feel in danger and attempt to take refuge action in SI (instrumental seismic intensity)=5.2 and feel anxious in SI=5.6. 2) When determining an evaluation curve by using probability distribution functions, using acceleration and SI are most suitable to the experiment results. Therefore, two kinds of the evaluation curves which use acceleration and SI are proposed.
To reduce the cost of jet grouting, we invented a new technique to construct rectangular-like columns instead of circular columns and set them in a row. This technique reduces the total number of columns, the production time and the production cost. Some field tests were conducted to construct the new columns. We succeeded in constructing the new columns and confirmed that the qualities and the construction efficiencies of the rectangular-like columns are not less than existing columns.
Bearing capacity of piled raft foundations in clay soils was studied using elasto-plastic three-dimensional FE analysis. Additional parametric analyses varying pile spacing to the previous study were conducted. Moreover, the bearing capacities of piled rafts obtained from the numerical analyses were compared with the published results from six loading tests of model piled rafts. Based on the previous and present study, it was found that a formula for evaluating ultimate bearing capacity of piled raft foundations, which is approximately equal to 0.8 times the sum of bearing capacities of raft alone and pile group, would be appropriate for practical use.
The objective of this study is the evaluation of the lateral ground resistance around a steel pile with wings subjected cyclic loading at a pile cap. This paper presents the ground deformation and subgrade reaction - pile displacement relationships observed in situ tests under cyclic loading. The hysteresis curves have slip characteristics in case of steel pile with wings. The lateral ground resistance of a steel pile with wings can be evaluate in a limited depth by simplify method using solutions of elastic pile equation.
In past research, elasto-plastic behavior of structure with cables under earthquake load and the snow load was reported. Although specific stress-strain relationship of cables was assumed in such research, reliable data is currently available in limited diameter and wire constitution. In addition, the elongation distribution in the tensile test along overall length has not been reported. The goal in this research is to grasp characteristics until ultimate state (fracture), and to propose reliable stress-strain relationship model generally adaptable of structural cables.
We develop a new type of deployable bar structure that simulates the folding process of rigid origami called Yoshimura-pattern. Since Yoshimura-pattern origami has multi-DOFs (degrees-of-freedom), it can be folded symmetrically and asymmetrically with respect to parallel valley fold-lines. In our proposal, additional revolute joints are assigned to restrict asymmetric motion of the mechanism and reduce DOFs. To confirm the deployability, we evaluate the DOFs of the mechanisms in various states using singular value decomposition of equilibrium matrix. The size of bars and the offset of joints are rigorously considered. Small-scale physical models are also assembled to confirm the deployability.
In this paper, we describe the example of the tunnel-shaped form building that was designed by structural morphogenesis and constructed. The genetic algorithms(GA) is applied to the structural morphogenesis of the framed construction of this tunnel type. In the numerical result, we show various solution forms of the arch shape by giving some design constraints. An effective structural form for the structure, the design, and the function is searched from the combination of the obtained arch shape. This simple structural morphogenesis procedure will become the hint of the design tool that decides the building shape.
In our research, we aim to provide a document that enable designers to easily recognize concerns which affect aseismic capacity of Kyo-machiya without carrying out frame analyses. To achieve the aim, we carried out frame analyses of typical frames to clarify concerns which affect their aseismic capacity in this paper. We revealed that the breakage of the through-column at the height of the beam or being pulled out and falling off of the beam may be caused depending on the deformation of the frame. These concerns can be solved by making the deformations of the first and second story uniform.
The new two type Massive Holz shear walls which doesn’t glued and can only be constructed with electric tools used by carpenters. In addition to the racking test results of the shear walls, a numerical analysis model of the walls with pillars stacked with nails or screws was considered, and a design formula to estimate the allowable strength by the performance of nail or screw joints was proposed. And the new type shear walls showed that they can be used for real wooden construction.
CLT is a structural material laminated and glued such that grain directions are orthogonal to each adjacent layer. Since CLT has an orthogonal layer, it seems that there is a possibility that buckling properties differs from lumber and glue laminated timber. It is not certain whether calculation formula of buckling strength used for lumber or glue laminated timber can be applied to the calculation of buckling strength of CLT. In this study, the calculation formula of buckling strength of CLT was proposed and the validity of the formula was examined.
This paper presents the results of bending experiments of traditional timber column joints reinforced by carbon fiber. The traditional timber column joint, which is called Kanawa-tsugi joint, is used for the test specimens. The unreinforced specimens broke at the joint and the maximum strength of the unreinforced specimen was much lower than the standard strength calculated on the assumption that the specimen is the uniform member without the joint. On the other hand, the maximum strength of the reinforced specimen was much higher than that of the unreinforced specimens. As the results, the reinforcing effect was verified.
In order to propose the opening reduction coefficient of the 5layer 5ply CLT wall panel, in-plane shear tests of the CLT wall panel with openings were tested. The knowledges are (1) the maximum shear unit stress of the CLT wall with opening excluding the opening area is from 2.0 to 2.2 N/mm2, (2) the relationship between the opening coefficient of the CLT wall and the stress ratio, the relationship of F=ϒ/(10-9ϒ) (at the real deformation angle) and F=ϒ/(5-4ϒ) (at the apparent deformation angle) are the best to predict these relationships.
Waki-machi Minami-machi in Tokushima prefecture is designated as the important preservation district of groups of traditional buildings, which is close to the Nankai trough and the Median Tectonic Line fault zone. Our structural investigation of traditional wooden houses there shows the seismic performance of several houses is not sufficient because of heavy weight and less of wall. Some houses have tilted pillars which are considered to have been caused by the residual deformation of former ground motions. Yield base shear coefficients correlate with natural frequency, and the houses with low yield base shear coefficient have low natural frequency.
The load carrying capacity of shear walls can be strengthened by increasing the number of nails or screws to the structural panel elements. However it will be difficult to secure the ductility as the strength increases. Therefore, in this research, a design method for a true wall type shear wall to ensure high strength and ductility was proposed. The shear walls were examined for case of using CLT or thick plywood as a structural panel elements.
To clarify the failure mode, the shear strength and the deformation capacity of the mortar finishing external wall which constructed by ventilation method, static shear loading tests of the specimens with 910mm of wall length were conducted. The maximum shear strengths of the specimen with orthogonal walls and the one with a plywood as a shear wall were remarkably high. The maximum shear strengths during the tests were observed at from 1/75 rad to 1/30 rad, and the shear strengths disappeared over approximately 1/20 rad. However, the mortar layer did not fall off.
This study involved the collection and analysis of data concerning the structural characteristics of approximately 600 high-rise RC buildings in Japan constructed from 1972 to 2015. The structural characteristics were analyzed focusing on differences in seismic resistant structures, seismic response control structures, and seismic isolation structures. The construction ratio of seismic response control structures and seismic isolation structures to all high-rise RC buildings increased with time. The number of floors and spans was increased because of the strengthening of construction materials and development in the technologies concerning seismic resistant structures, seismic response control structures, and seismic isolation structures.
High-panelized shear walls in which steel sheets with burring holes aligned along the vertical direction are fastened to frame members and are applied to low & mid-rise buildings in seismically active regions. The wall that receives the in-plane shear force allows shear stress to concentrate in intervals between the holes. Finite element analyses and in-plane shear experiments revealed that all intervals between the holes of the wall were simultaneously deformed, and shear buckling areas were limited in the intervals by ring-shaped ribs of the burring holes.
This paper reports an outline of a reconnaissance result of 185 steel school buildings including 102 gymnasiums damaged by the 2016 Kumamoto Earthquake. The reconnaissance has been performed by the Damage Evaluation Working Group of the Subcommittee on Seismic Performance of School Buildings, Architectural Institute of Japan. The structural, non-structural and overall damage has been ranked based on the “Standard for Post-earthquake Damage Evaluation of Damaged Buildings” published by the Japan Building Disaster Prevention Association. The damage rank of investigated buildings is shown and discussed in terms of building type, year of construction, whether seismically reinforced or not, etc. Some of characteristical damage of structural and non-structural components are also presented in this paper.
In light of the global environment, the authors proposed a building system comprising steel and timber (Hereafter referred to as CSTS), which consist of rolled section steels and timbers. A design method of the CSTS uses the concept of a damage controlled structure and its mechanical model is established based on the previous tests. In this study, we propose floor structure adapting for the CSTS using cross laminated timber. In-plane shear test of the joint which are consisted of unheaded studs or bolts for joint of the CSTS beam and floor structure is conducted. Structural performances of joint of the CSTS beam and floor structure are evaluated. The findings obtained from tests indicate that the joint of the CSTS beam and the floor structure has a high stiffness and strength.
The authors have proposed concept to realize beam yielding mechanism of a steel moment-resisting frame by applying a pin support system to midpoints of the first story columns. As a pin connection, an encapsulated-rubber rotational bearing is newly proposed. Seismic performance of the system is examined by a static cyclic loading test of a partial frame, consisting of the first story column and the second floor beams with an proposed rotational bearing. Test results showed a frame with a proposed rotation bearing had stable hysteresis behavior up to a story drift of 0.03 rad.
The main hall of Ohtaniha Hakodate Betsuin, which was completed in 1915, is the oldest temple architecture using reinforced concrete structure in Japan. The temple has been designated as an Important Cultural Property of Japan in 2007. In this paper, structural characteristics of the temple based on previous studies were described. Furthermore, evaluation of vibration behavior of the temple by micro-tremor observation and eigenvalue analysis using numerical 3-D frame models were presented. From the results, natural frequencies of the analytical model with decreased concrete Young’s modulus considering aging and construction situation showed a good agreement with the micro-tremor observation results.
Numbers of commercial buildings built before WWII are now considered historic monuments, yet most of them scarcely comply with current prescriptive fire safety requirements. This report shows an example of fire safety design for the preservation of Nihonbashi Mitsukoshi Main Store as cultural asset. The building features various weakness in fire safety including large open void penetrating five floors, staircases not satisfying the evacuation requirement etc. The proposed design utilizes existing fire shutters dividing each floor into three fire compartments as temporary fire refuges to overcome the weakness without changing any important historic elements of the building.
This research is to develop a new wooden hybrid column composed of laminated wood and concrete-steel. This hybrid column is called the EWECS column. EWECS column is made by covering steel with concrete and arranging laminated timber on the outside. However, this EWECS column uses laminated timber for the outer shell, but its fire resistance performance has not been clarified. Therefore, a fire test was conducted on a full size EWECS column specimen. As a result, it was confirmed that the EWECS column covered in this study has fire resistance performance of 2 hours as a column member.
Periodic inspection reporting system is the one which the inspector makes an inspection to the building equipment and the owner reports the result to the specific administrative agency in accordance with Building Standard Law. Our laboratory gathered the data of buildings about the emergency electric lighting system and smoke exhaust apparatus along with the administrative agency on 2013 and 2014. The reliability of these apparatus can be calculated using the data and the result will be very useful to maintain these apparatus for fire safety.
This paper reports a case study of performance-based fire safety design for a large scale underground car-park which was conducted by us; voluntary fire safety engineers of Japan Association of Fire Protection Engineers (JAFPE) for the international conference of Society of Fire Protection Engineers (SFPE). We constructed fundamental fire safety strategy which well take advantage of the characteristics of space arrangement, burning behaviour of cars and supposed occupants. And through analyses of smoke movement, evacuation behaviour and fire-fighting activity by combination of well-known methods and progressive methods, safety of occupants and fire-fighters are confirmed. We also report the other country’s proposals to investigate the possibility of different design approach.
In this research work, the goal is to elicit evaluation structures of the environment which is difficult to recall by memories or usual elements used in the original procedure of Evaluation Grid Method, such as pictures. Therefore, the new procedure is proposed, that is, experiencing selected actual environments as elements before judging preferable environments. This method including the procedure of experiencing actual environment is named the “Real-experienced-elements based Evaluation Grid Method”. The new method is applied on 3 kinds of environments which is difficult to recall by memories or pictures and their evaluation structures were effectively elicited.
A field study to improve sound environment was conducted in a nursery facility that worked on the reduction of its high sound level. First, sound absorbing materials onto the walls and ceilings, which shortened the reverberation time by half, was installed. Second, management efforts aiming for children to lower the loudness of their voices was conducted. These were performed with a demonstration of proper voice levels with animals of different scales and the generation of a music box sound during lunch. The effects of these trials were physically analyzed by sound recordings and subjectively evaluated by nurses.
A questionnaire survey on the children playing noise in nursery schools was carried out as a target for general citizens in Tokyo and the other prefectures. The survey collection rate is 17.7 % and the number of questionnaires collected is 341. The results show that a rate of the persons opposing the construction of nursery schools is about 10 %, and the reason of opposition for the construction is only feeling of an anxiety for the children playing noise. If the anxiety can be then dispelled, it is possible to resolve this problem.
This project suggested incorporating lighting into a lattice installed on the outer wall of a detached house. Because the light resembled light leaking from inside of the house, it was expected to improve the walkability, landscape lighting and crime prevention of the street. First, a lattice mockup was created and various lighting methods were examined. Next, simulation images of the night residential area were prepared and the psychological effects on the streets were evaluated. Based on the experimental results, this lighting method was applied to actual new distribution sites, and it was confirmed that the expected effects could be achieved sufficiently.
The thermal performance of Phase Change Material (PCM) is generally evaluated by itself. This paper aims to evaluate actual building envelopes including PCM, inputting interior and exterior thermal changes from an innovative experimental apparatus to both sides of the envelope. We conducted parametric study on PCM, interior surface and insulation, and evaluated the impact of these parameters on PCM performance.
Since adjusting the amounts of clothing worn within the home is an effective way to cope with increasing or decreasing temperatures, we conducted questionnaire surveys in summer and winter in order to gain an understanding of how heating and cooling equipment are used as well seasonally, as well as how the amount of clothes worn changes with indoor climate conditions. The results show the following points: (1) there were differences in preferred air-conditioning temperature settings among age groups, (2) clothing amounts worn within the home differ for males and females, and (3) the amount of clothing worn affects air conditioner usage.
In this paper, analysing result of indoor environment and air conditioning load properties based on real measurements to contribute capacity design of the air conditioner obtained in important equipment rooms is shown. As an analysing result, it is clarified that the grasping the amount of the heat generation is necessary for designing of air conditioning load even in the important equipment rooms. Therefore, data of important equipments’ heat generation obtained by real measurement are organised and shown.
This paper discusses about an examination of an energy management method for multi-sprit type air conditioner using centralized controller with a function of gas rate proportional division. The objective system is a gas engine heat pump air-conditioner installed in an agricultural research building. For energy conservation of multi-sprit type air conditioning system, comprehension of focal points in measures and identify on priority target rooms were carried out by analysis of factors which contribute to heating and cooling energy consumption using actual data. In addition, examples of an analysis method for the operating situation and estimating performance of air conditioner were specifically shown.
The current study was conducted as a response to the need for clarifies the influence that Rokko Mountains give to the water depth of the Toga River using information from the iRIC program and rainfall observation results during the local concentrated heavy rain. The water depth using information from the iRIC program for only an urban area in Kobe city is the almost same as the rainfall observation results. Our information results from iRIC program showed that rainwater infiltrated the ground of Rokko Mountains during the local torrential rain.
In 1989, district heating and cooling system using river water heat was introduced for the first time in Japan, at Hakozaki. And this system was improved with a renewal in 2012~2014. It was improved the washing method of the heat pump tube and the control method of river water intake. This paper presents a study on improvement effects with a renewal of DHC system using river water heat.
Recently, the number of renovation with external thermal insulation for energy-saving has been increasing. This report shows four experimental studies on external thermal insulation system for apartment houses. First, based on noncombustible certification test, it was found that the system was composed of noncombustible materials. Second, as the result of test for tensile strength, the system turned out to have the durability to wind load and strain. Finally, strain test and exposure test were carried out. The result showed that strain was within the permissible range in the system through changes of temperatures and weather conditions.