We study the strength development of massive concrete using fly-ash. We propose a new idea of concrete strength control method. 1) Concrete mix proportion may be designed that the concrete strength of massive structures satisfies the specific design strength until 91 days of concrete ages. 2) In the case of the B-type fly-ash cement or substituting fly-ash for 15-30% of the cement, standard curing specimens are tested at 28 days for the strength inspection. 3) In the case of substituting fly-ash for 45% of the cement, standard curing specimens are tested at 91 days for the strength inspection.
The thermal effect of fiber reinforced concrete was estimated by using FEM analysis. As a result, fiber reinforced concrete has high durability on heat shock. And one of FEM analysis for fiber reinforced concrete was proposed.
Carbon fiber reinforced concrete, especially made by direct spray-up method was researched. Especially the effects of size agent and fiber properties were measured. Conclusively, size agents have much effect on the strength of carbon fiber and concrete composite.
Mass precast concrete elements for columns and beams have been developed in recent years to improve the quality of reinforced concrete structures and simplify their methods of construction. The object of this work was to study the temperature history of mass precast concrete elements in their production process. By heat curing from the outside and internal storage of the heat of cement hydration, the mass precast concrete elements showed different temperature history from the thin precast concrete elements for walls and floor slabs. The temperature history at the center of mass precast concrete elements was different from that at the surface of mass precast concrete elements. A larger section size of elements resulted in larger difference in temperature between the center and the surface of mass precast concrete elements.
Mass precast concrete elements for columns and beams have been developed in recent years to improve the quality of reinforced concrete structures and simplify their methods of construction. The object of this work was to study the strength of mass precast concrete elements. The mass precast concrete element showed different strength from the thin precast concrete element cured under the same heating condition. This is attributed to the difference in temperature history caused by the internal storage of heat of cement hydration in the mass precast concrete element. Using the maximum temperature as a parameter, the strength could be uniformly predicted regardless of the section size and the position of precast concrete elements.
Each column of the information hall is cross-shaped and prestressed concrete with approximate three-degree slope and notches at four corners. The inner parts of columns are made of PC steel wire, PC steel rod and high-density bar arrangement. This time, we used super workable concrete for construction of each column and got the satisfactory finish results for the designer.
Recently many new methods have been developed to prevent tilework fall-off. However, standard testing procedures have thus far not tried to determine the seismic resistance capacity of these methods. In this study, seismic tests were conducted using true-to-scale specimens of tile-covered walls in order to accurately determine the seismic resistance capacity of these methods. It has been concluded that, particularly, above a lst-story deformation angle of 1/250, a cyclic load leads to a loss of bonding strength. The seismic test also revealed differences in the performances of tiling methods, especially above a deformation ratio 1/250. The method utilizing a three-dimensional knitted fabric covers cracks in concrete walls remarkably well and resists cracking and delamination.
The products of each domestic structural steel makers may vary in the property and chemical composition. In this research paper, data of products actually used in a project were collected from inspection certificates received from suppliers. The chemical elements and mechanical properties of each product were categorized and statistical methods were taken to find out the distributions within the parameters specified in Japanese Industrial Standard (JIS). Our research showed that the chemical elements and mechanical properties of products of each plant were met by the standards defined in JIS with some differences in the form of statistical distributions in the results of each plant.
This paper deals with durability test results of tiling system adhered with elastomeric adhesives. Because the system is regarded as to be effective to prevent breakage of ceramic tiles on concrete wall, the durability of the system has to be cleard in order to apply on the actual wall. With tiled concrete specimens, tests such as heat aging, outdoor exposure, immersion in alkaline water and freezing and thawing were made. In addition to the tests, heat aging and hot water immersion were made with adhesive specimens formed in sheet. Changes of adhesive performance during the tests were detected in adhesive strength with tiled concrete specimens, and tensile properties with sheet specimens. And then, heat aging has been discussed based on the theory of chemical reaction rate.
The importance of quality control of welding in relation to heat input and interpass temperature is strongly indicated based on various experimental works done after 1995 Kobe Earthquake. This paper presents a most probable quality control method which can not only verify the conformity of the welding procedure but also be utilized for education/training of welding skills.
Basic study on the optimum seam welding of membrane made from titanium sheets for waterproofing roof construction has been carried out by means of various tests such as peal tests, water pressure tests, appearance tests, microscopic observations and sectional hardness tests on the welded specimens prepared in compliance with JIS H4600 Class 1. As a result, it has been confirmed that the specimen welded under appropriate conditions, including the area close to the clips' edges, has no issue for the purpose of use and has a sufficient peal strength over 62N/mm comparing with that required from the wind resistance performance.
This paper reports the fabrication and construction of the fixed roof of Toyota stadium. The fixed roof looks like a crescent moon and covers the main & back stands. It's composed of keel truss, sub-truss, combined beam and horizontal brace. This paper describes the control process of the fabrication, referring to drawing, casted steel, optimum method of welding, combination of various joint plates. Also this paper describes the erection process of the roof on site.
Durability design of concrete structures is now one of the main issues in the field of structural engineering. Since the durability depends mainly on the pore structures of concrete and the environment to which concrete is exposed, data of concrete temperatures and moisture content are essential for the durability design. For collecting the data, concrete specimens with different water-cement ratios were exposed in the open-air. In this paper, the experimental results of the temperatures and moisture content in concrete are reported and they are briefly discussed in relation to the climatic conditions, the sheltered condition and the pore structure.
A porous concrete block divided into small pieces for human handling was applied to the base of roof gardens. Effects of the surface shape of the block on the germination and growth of lawn were investigated. It was found that the plant growth on the porous concrete-based roof garden may be improved when the block has a surface layer with a total porosity more than 36 percent.
Greenery concrete using both coal clinker ash and fly ash was developed as a new technique for recovery of nature. It was applied on a part of steep slope at the construction site of Tachibana Bay power plant. In this paper, the overview of the project and the construction methods on the cut steep slope and the investigation results of growth of trees were presented. The pre-cast porous concrete block, which has holes for root balls of trees, was used. Then, water retainer was filled into the void of the porous concrete and the thin layer of soil was sprayed. Almost all the trees showed good growth on the greenery concrete.
This paper reports damage control design of flexible RC tall buildings using high-strength materials. This study first outlines the points of damage control design. Then, it further outlines experimental study to confirm the effectiveness on damage control design of flexible RC frame using damper and high-strength materials and to study the joints between damper and RC frame. Lastly it outlines comparison of the damage control design and ordinary design of a high-rise RC building. It was confirmed that the joints between damper and RC frames have enough capacity to create the damping effects and the damage control design is effective for economical aseismic design.
An FBG (fiber Bragg grating) accelerometer was developed for buildings and civil infrastructures. The accelerometer has a high sensitivity in low frequency range to cover the most important frequency components of the structural response, typically below 50Hz. The optimum design procedure to realize the maximum sensitivity under given constraints was developed considering two mechanisms. The proposed FBG accelerometer takes the advantage of an L-shaped angle element with its leverage effects. The lifetime of the developed sensor was also evaluated based on the crack theory. The lifetime of a sensor system consisting of ten FBG accelerometers was shown to be more than fifty years.
200kN MR damper was developed as a variable damper using two kinds of MR fluid. One is commercial product, and another is trial product. The experimental tests were conducted by excitation of sinusoidal wave, triangle wave, and random wave. As the result, the expected damping force was generated, and the basic characteristic of the damper was observed. In the domain of 0.15 [cm/s] to 20 [cm/s], force and piston velocity are in a proportional relation mostly, the fluid of trial product was understood that the ratio of force to piston velocity is larger and the width of the change to electric current is also larger compared with commercial fluid. When the period for the growth of the damper force by electric current was measured, it turns out that it has sufficient reaction speed.
A new smooth-curve hysteresis model for laminated rubber bearings, named 'Modified HD model' is proposed. Its simple formulation can be easily applied to both lead-plugged rubber bearings and high-damping rubber bearings, employing the parameters in widely-used modified bi-linear models. The hysteresis loops by the modified HD models have good agreement with those by loading test of laminated rubber bearings. The results of earthquake response analyses for a tall base-isolated building using the modified HD model are compared with those using modified bi-linear model.
We have examined the effects of heavy traffic on dispersion curves analyzed by the space autocorrelation method. In order to observe short-period microtremors circular arrays of six seismometers with radiuses of 5 and 20m were deployed at the position 200m away from a road on which traffic was heavy. We took out waveforms with durations of 10s from the array data, and estimated power spectral densities and spatial autocorrelation coefficients. Changing the start time of the waveform segments, we repeated this procedure over entire records. It is revealed that the phase velocities analyzed depend on the intensity of microtremors.
This paper concerns the behavior of the coal storage facility during the push up work using the pantadome system. The characteristic of the structure is the shape of the plane and the section. The plane is the heptagonal doughnut shape. The section is the mountain shape that three hinges line up on a nearly straight line upon completion. We focused on the transition of the reaction and the deformation at the push up points, transition of the movement of the hinges and the structure behavior. The analysis during the push up work and the measured results of execution are reported.
Main objective of this study is to structure database, to investigate the trend of timber engineering research, and to produce a retrieving system. New retrieving system on world wide web site is developed. This system is based on CGI and written by Peri which is program language. In this paper, the outline and the operating manual for this system is introduced.
In this study, rotation rigidity and strength of the joint were evaluated through bending experiment of the joint using round bars and drift pins. Next, rotation rigidity (necessary rotation rigidity) of the joint of the timber frame structure which satisfied story deformation angle restriction of 1/200 and distortion angle restriction of 1/300 of the deflection of the beam was quantitatively grasped, and it was examined for the joint proposed here.
For rationalization of construction work, a new construction method for R/C column using a precast concrete shell was developed. By a new method of assembling tie-hoops and constructing inner forms, and using high fluidity concrete, four workers can construct two high quality cast-in-place precast concrete shells in a day. In the case of a high-rise building, when a unit construction method is adopted (unit consists of a precast concrete shell combined with column main reinforcement and beam reinforcement) installation expenses decrease with work efficiency increase, a 14〜25% reduction is possible over the conventional method in respect to the length of time for skeleton construction work, the number of mechanical joints for reinforcement is decreased by about 25%. This can reduce the cost for skeleton construction of 32-story building by about 3%.
In this paper, a simple column-beam joint in steel structures is experimentally studied. The joint is achieved by means of filling steel fiber reinforced cementitious composites at the gap. In the test, simple beam specimens are employed by filling both steel fiber reinforced cementitious composites and concrete at the joint, and unidirectional cyclic load is applied. The empirical results show that the specimens with steel fiber reinforced cementitious composites give enough stiffness and strength without prominent damage in comparison to the specimens with concrete. It is concluded that the simple column-beam joint with steel fiber reinforced cementitious composites is applicable.
For six years, We have performed comprehensive study on application of Steel plate reinforced concrete (SC) structure to buildings. It includes (1) experimental study on structural and fire-resistant characteristics of SC structure, (2) analytical study on evaluation of design method by using the experimental study and so on. Then, we have completed our study through many practical works and the results of the study are summarized as the earthquake-resistant design (including structural design) and fire-resistant design recommendations. Here, we report the typical earthquake-resistant design methods of SC wall among them.
The following were observed as the results of questionnaire survey for building users and experts. They all have a clear idea and they want to suppress hazard severity to a small level. This is more evident for "hazard to human life" and "loss of property value" than for "function of building". If the fuzzy relation is used, the membership functions with respect to the structural damage level can be obtained from the performance requirement level. The performance requirement level is determined by users and owners for "hazard to human life" and "loss of property value". It thus becomes possible to convert the performance requirement level determined by users and owners to a structural damage level.
The monocoque sandwich panel roof has been developed. The production process is called VARTM (Vacuum Assisted Resin Transfer Molding). The panel is composed of two facings with CFRP skin, core between the facings with phenol foam and ribs connecting the facings with GFRP. Experiments were conducted on the flat panel elements and the full-scale U-shaped shell. The experiments verified that local buckling (wrinkling) of facing was critical and the structural behavior was elastic till the local buckling was occured. Based on the experiments, the strengths and the safety factors for design were decided. The CFRP sandwich shells were applied to some gymnasium roofs.
The ball-void slab (B. V. S.) is a slab with the spherical void. Vibration measurements with the discrete calculation method on the floor impact sound insulation performance of ball-void slab were carried out. Four specimens of the full-scale section model were measured. One specimen was the ordinary solid slab and the other three specimens were void slab. The void was used rectangular type (one specimen) and sphere type (two specimens of 200mm and 240mm in void pitch). Through this study, it has been revealed that the ball-void slab has advantageous features on the floor impact sound insulation performance with increased void ratio of the slab.
JIS A 1418-2, which provides the measurement method of floor impact sound by standard heavy impact source, was vastly revised in January, 2000. It provides about the ball which has the different characteristic of impact force(II) from the tire before now. However, there has been a problem that big change of impact force by the ambient temperature, because the development has been executed for the ball made of rubber before now. Then, we tried to make the ball made of silicone-rubber, and examined the reasonability of heavy impact source from the point of view of impact force characteristic and floor impact sound.
We executed an questionnaire survey inquiring about engineering level on sound insulation of walls and floors of wooden apartment buildings recently built in Japan. (This questionnaire, however, was practically executed in 1994.) Answerers were Japanese researchers and engineers whose specialty was sound insulation of buildings. In this paper, we introduce the results of this questionnaire and give our opinion about sound insulation performance of walls and floors of wooden apartment buildings.
The Housing Secure Law was executed on April the 1st in 2000 in Japan. This law regulates the new official labeling system about dwelling performance. To execute the system practically, the labeling standards of some building performance (i.e. earthquake resistance, fire prevention, heat insulation, sound insulation, etc.) was promulgated on July the 19th in 2000, and this official system was started on Oct. the 1st. In this paper, we introduce the sound insulation standards of wall, floor and window opening of dwelling buildings (especially apartment buildings), that are regulated in this law.
Recently, due to deeper interest in the problems of global environment, the low energy and/or low impact buildings were started to be built in Japan. It is very important not only to design several demanded performance, but also to evaluate these buildings by the residential data. In this paper, data of 30 residential houses designed in considering of energy efficiency, were collected. These houses were evaluated from the viewpoint of indoor thermal environment and energy efficiency.
It is too difficult to evaluate cross ventilation quantitatively. In this report, the effective volume index, which shows the diffuse degree of tracer gas, is applied to the steady cross ventilation. And then the effective volume index is examined by using CFD analysis, spatial characteristics are decided by such volume. In conclusion, it is confirmed to be able to evaluate whether the cross wind passes through the room without most mixing air or it mixes room air immediately.
We have been applying the fluid analysis to predict an indoor thermal environment and an outdoor air flow. In this report, we describes the development of a virtual simulation system for housing environment using the Rapid Prototype method. As a target of the development of this system, a number of days to simulate the environmental performance of an individual residence was set to a period less than three days subject to the condition that the relating CAD data is presently available.
This paper presents the development of warm air heating system using crawl-space as heating chamber for single family house. To establish proper system, required opening area for air convection on the floor and air convection wall, is discussed through simulation. Developed system is applied to the practical house and their performances are measured. The results indicate that this system creates comfortable indoor thermal environment in the heating season.
Wastewater treatment systems using garbage disposers, for breaking garbage to piece and treating, make a contribution to a decrease in quantity of garbage. Not only for house, systems for business use are effective, because of treating a large quantity of garbage. The past reports were about systems for house, but this report is about system for business use. This study proposes performance evaluation method, and examines measurement results by setting up it in practical building.
This study was conducted focusing on communication of elderly people. Using multimedia equipment makes closer communication between elderly people and their family as well as other people. The result shows that people in the community can share the sense of assurance.
Thermal environment, especially air temperature distribution, inside the semiclosed arcade located at Nagasaki was investigated on field observations both in summer 2000 and in winter 2001. Air temperature at the height of 1.0 meter in the occupied zone was a little higher than outside air temperature both in summer and in winter. In the daytime of summer, vertical distribution of air temperature showed a slope of high temperature in the upper part and low temperature in the lower part. However, both in the nighttime of summer and winter, vertical distribution of air temperature did not show a slope.
A house with passive ventilation system in Morioka City was surveyed relating with indoor thermal environment. It was proved that indoor temperature was kept at about 18℃ all through the day in winter. Indoor thermal environment at the living room in winter was good. But the cold draft from the second floor flowed into the living room in the night. And relative humidity in the room was low in winter. Air change rate in winter was much, and it was necessary to adjust air change rate. Energy consumption was more than the average energy consumption in Tohoku district.
A breathing wall using rice straw charcoal was applied to the solar house, which had a floor heating and cooling system using outdoor air. In order to investigate the possibility of practical use of the wall, thermal and moisture characteristics of the wall were experimentally examined using the actual sized walls installed in the solar house, which was situated in suburban Tokyo. As a result of the outdoor measurement, it was found that high humidity condition in the walls did not last longer than a day from winter through summer. Moreover, in spite of high wind velocity condition in summer, the difference of temperature between the walls inflow-surface and the room showed less than 3K.
We held a workshop of Klimaatlas on 5th March 2001 in Kobe. This workshop was held for an examinations of making process of the recommendation map besed on climate analysis data. Through the workshop, we could extract the three points that are conjectured to be important when we design the city structure and the buildings considering the local climate's characters.
Planning promotion room, Chiba university has developed Facility Management Database System (FMDS) in order to promote effective facilities use. It consists of CAD-based system and network-based interactive system. Latter was designed considering cost-benefit in databese construction and maintenance. It enables any users to input and revise the relevant data at any time from any terminal via Internet. With its functions of retrieve, aggregation analysis and publication, it will be helpful in various decision-making situations. In this paper we introduce the history of our FMDS development, examine problems we found and finally discuss the direction of the future FMDS.
Wayo Women's College, Konodai campus project, is a 10-year redevelopment of an old existing campus. It's planning process acknowledges the surrounding environment with its vital connection to the site and the ability to reach a level of sustainability in relation to the design goal and function on the campus. A well-coordinated approach in research, education, and facility initiated a systematic master program and plan which is characteristically obvious and effective to all parties concerned. It has also become the base and essential concept in the redevelopment of the city as well.