Recently progress on high quality recycled aggregate production techniques has been made rapidly. This paper deals with utilization of by-product powder generated during high quality recycled aggregate production for concrete admixture. Compressive strength and drying shrinkage of mortar containing large amount of the powder as a part of fine aggregate or cement were investigated experimentally.
Five kinds of advanced fivers, carbon, polypropylene, hydrophilic polypropylene, sepiolite, and aramid, were assessed for the substitutes of the asbestos that had been used as a standard fiber additive of extruded cementitious materials. Each linear line with the logarithm of the repetition number indicates the strains caused by the wet and dry repetitions. The amplitude strain and the residual one become stable at lower water content ratio in the early stage of the repetitions. The study found that treating the surface of the fibers like asbestos, mixing the fibers fully, and managing the extruding pressure were crucial to avoid the redundant shrinkage and expansion of materials.
There was a problem of always securing prevention of an initial frost damage and prescribed strength in construction in winter of housing foundation concrete. PTC ceramics were developed as a new technology to solve the problem and the heater element heat curing seat industrial method was developed. It is a safe, reliable care method because PTC ceramics are the resistance bodies into which resistance sensitively changes depending on the temperature, and the ambient temperature is detected and it controls the calorific value automatically. It was confirmed that it was a concrete care method with effective this care method from the care performance examination result and the construction data compared with the method of taking care of one's health the heating of the past etc.
The absorption factor of an Oya stone is very high, and it sexpands greatly when it absorb water. Moreover, the compressive strength in the wet condition quite falls less than in the dry condition. Furthernore, as compared with details of the stone, the specific gravity of rough-textured Oya stone is small, and its compressive strength is also low both in the dry and wet condition. The swelling pressure is hardly produced even if the Oya stone absorbs water for a long time, and then the internal structure is vulnerable. We are going to get behind the behavior of the Oya stone in this study.
Steel sandwich panels with polyurethane formed core and cold-formed steel surface have been widely used for the material of building walls and roofs. The roof panels that resitent to wind load is effective to meet the requirement for finishing materials. Authors have proposed roof panels for improving structural performance of steel sandwich panels, and also reports experimental results of reinforced washer with drilling-tapping-screw for steel sandwich roof panels.
It is necessary to examine the foundation, the T type wall, the corner wall, the brick beam, and the connection of floor and interior materials to actually construct it by the SRB-DUP method. In this .study, it was examined that the construction technique and detail of the SRB-DUP brick house to actually construct it. The conclusions are as follows. It was clarified to the SRB-DUP method that an original management technique that was to set up the anchor bolt in the foundation, placed the self leveling, and managed vertical accuracy of the brick wall by using leveling string at the bolt position etc. was necessary.
In this study, the logic of the brick and the plate layout to draw a working drawing was examined. The application to design automatically in a brick and plate layout drawing that greatly reduced the labor and time was developed. The developed CAD system to design a brick layout drawing was operated, and the brick layout drawing was made as a case study. The conclusions are as follows. In the plan to have done the case study, it was able to complete the brick and plate layout drawing in about four days. It became clear that it was able to shorten time to draw in the working drawing and to decrease the construction cost considerably.
When I repair it while using a building, as for the outbreak of the noise and vibration in quakeproof reinforcement work with underpinning construction of an established structure, it is very likely that I give the influence for the livability. Here, I show the nois/a vibration measurement result at the time of foundation work in the seismic isolation retrofit of the main building of the National Museum of Western Art main building which I carried out in 1997 and, about the noise, compare it with recommendation value of dB(A) of the occupied room noise by 1,988. Beranek and grasp noise environment by a measurement result of the noise in each floor by each work process. According to the encouragement value of dB(A) of the indoor noise of occupied by Beranek, 1988, it is thought that execution in the range that considered noise environment by being almost lower than 50dB(A) in a floor leaving more than the second floor is possible.
Applicability of high quality recylced aggregate to mass concrete of nuclear power plants was demonstrated using models simulating Pre-stressed Concrete Containment Vessel, measuring thermal and strength characteristics. Analysis on thermal cracking resistance for the reactor containment showed that the mass concrete using high quality recyceld aggregate was superior to ordinary aggregate concrete.
The first purpose of this paper is the development of recycled PVC sheets which is applied as floorcoverings, and second purpose is development of fiber reinforced plastic sheets which containing fiber of the waste carpet-tiles. In this research, we deal with three kinds of waste PVC floorcoverings (Homogenias-tail, PVC flooring sheets, and carpet-tile) as the recycling raw materials. Tension tests and dimensional stability (bathed in hot air at 80℃, 6hrs.) tests on recycled PVC sheets specimen were performed. As a result, the influence of proportioning and fiber mixing rate on the quality of the recycled PVC sheets was clarified.
Aichi Prefecture has operated "Evaluation System for Recycled Materials in Aichi Prefecture (Ai Cle)" from FY2002. This is a new evaluation system aimed to expand the use of recycled materials in public construction. Ai-Cle adopted Evaluation Standard of Recycled Materials, "Ai-Cle" Material Qualification System and Aichi prefecture's "Ai-Cle" materials Priority Use Policy. These correspond to the material procurement of public construction. As a result, recycled materials are much utilized in public construction which needs a mount of construction supply. The number of authorized material is reached to 1,000 and is further increasing.
In this report, the stability and applicability of fishing bank made by large particle size porous concrete was examined in the large-scale waterway where wave and current can be generated. It has been found that void of fishing bank decreases power of current and wave, and the effect on wave is especially large.
Recently it is increasing that public concern about a surrounding landscape. The purpose of this study is to examine the relationship between the color properties of facades elements of the series of building and the impression evaluation. The method to improve the appeal of appearance and to harmonize the elements color of building facades was proposed.
There is now a demand for aesthetic qualities of buildings to be maintained for a long period. With the basis of such a background it is important to select the color of building carefully. The purpose of this study is to examine the relationship between color properties of roof material of sloped roof type apartment and the impression evaluation. Factors of colors, inclination of roof, building figures to improve and harmonize the appeal of appearance was cleared.
The purpose of this paper is to clarify seismic safety of ALC curtain wall under severe earthquake ground motion, and seismic deformation tests were performed about critical differential movements of the ALC curtain wall and fall-off capacity of tiles. In addition, adhensive strength test and a deformational performance test were conducted to compare normal tiling system and R-tile system which is supported of metal and mortar for renewals of external walls. As a result, the tile did not fall-off though adhesive strength of the tile was small inthe R-tile system. Therefore, it is thought that R-tile system can be used as a tiling system for renewals of external walls.
Insufficient cover thickness of concrete can cause corrosion of reinforcements in concrete members at earlier age. This earlier deterioration, such as carbonation and salt damage, is sometimes caused by enlargement of water-cement ratio at surface part of concrete cast in impermeable wooden sheaths used in general concrete works. However, this non-uniformity of water-cement ratio in concrete members is not considered in the standard specifications. Therefore, a design method for "effective cover thickness" was proposed. The effective cover thickness, considering this non-uniformity in concrete, was defined as the cover that could be evaluated to obtain equivalent durability, using uniformity of concrete. The effective cover thickness could be evaluated by the coefficient of carbonation rate and the diffusion coefficient of chloride content determined by the profile of water-cement ratio in concrete members. As a result of the evaluation, deterioration of concrete could be accelerated as cover thickness was thinner and water-cement ratio was larger.
Under the enforcement of several recycle regulations in recent years, the reception and demand of waste glass became in large quantities and great diversified. The demand for recycling method is increasing. Toward this situation, the investigation of the limit of reception towards waste glass and the method of making them become resources through utilizing their characteristic of framework became necessary for recycle treatment industry which aimed for other usages. Therefore, in this thesis, the nature of wide range waste glass is specified by its composition and the estimated melting point based on X-ray analysis and melting experiment.
This paper presents the effect of surface soil in the horizontal force distributions in earthquake responses along the height of mid-rise reinforced concrete buildings. It is dealt with a lot of surface soil models and artificial earthquake waves to input into these models. Surface waves filtered through surface soil are calculated. Then, we input those surface waves to the reinforced concrete buildings to obtain earthquake responses. Consequently, we investigate the horizontal force distributions in the earthquake responses of the buildings and propose an evaluation method of these distributions.
The ultimate capacities of natural rubber bearings are defined by compressive stress, shear strain, and stabilized restoring force. The experimental study about these capacities was reported in the previous paper. In this report, the experiments were additionally conducted under the higher pressure for rubber bearing. Considering with the added results, the ultimate capacities were more clarified. Based on test results, the added ultimate capacities of rubber bearings for designing was proposed.
The authors have been developed a series of teaching materials showing vibration test, which are called 'bururu', for educaiton of dynamics in University and the enlightenment of disaster prevention consciousness in the society. Here, the 1/10 scale wooden house model placed on hand cart, which is a kind of shaking table, are developed in order to demonstrate the seismic weakness of wooden house for the promotion of seismic retrofit. This model easily show the difference of collapse due to the amount and the balance of seismic resistant member, joint of members, weight of roof, soil stiffness etc.
Lumped mass model is often used in nonlinear dynamic analysis for its simplicity. But it may not be appropriate for estimating the response of the frame model, because it is difficult for the lumped mass model to evaluate the effect of increasing plastic members. Improved lumped mass model with multi-springs is proposed in this paper to provide more accurate load-displacement relationships. This study demonstrates that proposed model provides good estimates of the response of the frame model.
In this paper, we have proposed the new construction method of pre-cast post including the panel, made of ordinal strength steel, as a hysteretic damper for the RC frames consisted from pre-cast members. To confirm that the proposed method would be surely capable to be constructed and have a sufficient structural ability, we carried out grout pouring test and loading test. The results show following facts, 1) The proposed post with the panel type stiffener attached to the panel shows sufficient abilities of deformation and energy absorption. 2) Working shear force between main frame and post is transferred.
Demand for monitoring systems applied to structures for quality assurance and for evaluating seismic risk is stronger than ever. Here, a monitoring systems to assess structural integrity was developed in which the damage-detection strategy uses two methods to first identify the damage sites globally (i.e., detect whether the damage occurred or not, and detect the story level) and to then evaluate the damage sites locally. It is shown that the local damage identification used the wave propagation method to analyze a concrete bar. Results showed that these two methods are practical and effecive in assessing structural integrity of a structure for seismic safety.
This paper presents that development of a cost-effective method of seismic isolation system for residence. This perticular construction method makes use of seismic isolators with compact and simple bearing and damping materials. With an RC structured base isolation story, the entire construction method, including installation of the seismic isolator, was possible using conventional construction techniques. Development of this construction method required construction and structural experiments. Results from construction experiments proved that the method developed is satisfactory in producing the base isolation story, while structural testing proved that there is positive capacity for vertical loads in the base isolation story, and that satisfactory earthquake protection was present
In this paper, the authors studied the characteristics of simulated long period earthquake ground motions and their effects on the responses of base-isolated buildings. Analytical structural building models for response analyses were generated based on the data about exisiting base-isolated buildings. Earthquake response analyese were carried out for the building models subjected to long period earthquake ground motions to find how the design parameters and the input motions affect the maximum earthquake responses and the margins of seismic safety. The response analyses indicate that the design earthquake motion for base-isolated buildings should be provided as an energy spectrum as well as a response spectrum.
A dual vibration monitoring system of a base-isolated building is developed to observe both strong earthquake response and continual long-term ambient vibration. The advantage of the monitoring system is to obtain a complete set of an earthquake record and the ambient vibration records before and after the earthquake, which are useful to establish vibration-based techniques for structural heslth monitoring (SHM). This paper presents the detail of the monitoring system and its recent results on SHM studies by the authors. The results show that the day fluctuations in the first and second natural frequencies are mutually independent, and slight change of the modal parameters between ambient vibration tests conducted at the different time, which can be introduced only by the long-term vibration monitoring.
This paper describes development of the new hybrid aerodynamic vibration system and verification of the developed system for simulating aerodynamic vibration of structures. Simulation of aerodynamic vibration of a square prism in 3-dimensional flow is conducted. Unsteady aerodynamic force can be estimated in this simulation. From the results, the accuracy of developed system is satisfied and the hybrid aerodynamic vibration technique suggested some possibility to analyze aerodynamic vibration of structures from other angle.
This paper represents the hybrid technique for verifying the interactions between the structural model and the surrounding air flow. In this technique, the external wind force is measured using the multi-simultaneous air pressure sensors, and the values of the pressures are transmitted to the computer, and then the response deformation is calculated by the numerical calculation. Based on the results of the calculation, the model is moved forcibly. The interactive phenomena can be reproduced on this technique in this way. To verify the accuracy of the technique, the simulations for aerodynamic phenomena are performed on this sytem. The wind tunnel tests for an oscillating square cylinder in the 2D flow are simulated and examined.
This report describes about new vibration control system using resonance of water sloshing in a U-shaped water tank whose natural period is adjusted to that of the main structure. One challenging issue is to control the structural responses in both horizontal directions with a single water tank. This paper proposes a design formula for calculating the natural period of the system by examining the measured results of devices installed in an office building. The damping effect of water sloshing, including fluid resistance of the water tank and supplemental damping devices submerged in the tank, is also examined analytically. Finally, advantage on the system is confirmed using observed response of actual building with earthquake and strong wind.
This paper presents the evaluation of first mode damping ratios, first mode natural frequencies and amplitude dependences for a steel building based on measuring data. The building is 50 m height, rectangular plan and it was completed in March 2004. Many data are simultaneously collected in two horizontal directions at optional points on the roof floor since April 2004. We investigate the center of rigidity on the roof floor based on microtremor measurement. It is clarified characteristics of first mode damping ratios, first mode natural frequencies, and amplitude dependences on the center of rigidity based on microtremor, man power exciting, strong wind, and earthquake measurement.
Dynamic characteristics of buildings are key issues in the seismic design technology. From this point of view, Building Research Institute is operating the strong motion network for buildings since 1957. In this paper, dynamic characteristics of actual buildings are estimated using acceleration records of the BRI strong motion network. For an instance, the transition of natural periods and damping ratios of the slightly damaged buildings by an earthquake are examined using the moving time window technique. The change of dynamic characteristics depending on displacement amplitude can be verified. Relation among natural periods, damping ratios and building heights is also discussed.
This paper presents a new practical approach (named "CEM") for quickly and easily calculating the settlement of piled rafts in layered soft soils. We introduce the new concept "the equivalent column" for pile and surrounding soils in the method. Calculating the settlement of piled raft using the CEM provides a close approximation to results observed from the 5-story and the 3-story buildings in Tokyo area, as well as obtained from parametric studies bv the three-dimensional finite element method.
A falling mass type of rapid loading test, referred to as FM test, suitable for small diameter steel pipe piles has been developed. The loading test method is adopted for piles installed in clayey soils and simple method to evaluate pile performance from the FM test, including the use of accelerometer record to evaluate the pile head displacement, is proposed. The pile head displacement obtained from acceleration record during loading tests conducted on small diameter screw pile is compared with directly measured values and the agreement is fround to be satisfactory for practical purposes. The effective use of the FM loading test method for quality assurance of small diameter steel piles is suggested and the evaluation of the bearing capacity of piles installed in sandy soils are also reported.
This report presents an effect of phase characteristics of seismic wave on earthquake damage of building and pile foundation. Seismic responses of a soil-pile-structure system are calculated for six waves whose phase characteristics are different. Soil non-linearity caused by soil strain and liquefaction is considered in calculations. Coefficients of variation about structure and pile damage for six waves are estimated. The non-linearity of liquefaction makes large the coefficients of variation because non-linear responses are influenced by phase characteristic of seismic wave.
Wind load was critical for the design of tele-communication tower than earthquake load so far, however, recently expected earthquake load become more critical than wind load according to the latest researches. In these cases, some towers could be damaged with member buckling, so these members need to be reinforced. However, very few retrofit methods have been put in practice for such existing towers. In this paper, a seismic retrofit method for tele-communication towers using buckling restrained braces is discussed, and analytical evaluation of the effect and practical construction record are reported.
In this paper, the static loading experiment on the two story timber frame structure using drift pins are reported. The experiment was carried out in two construction stages. The first stage is the one in which the columns, the beams and the floors were constructed, and the second stage is the one in which the bearing walls were added to them. The contribution to the stiffness of this wooden structure by the frame and the bearing walls are examined experimentally.
This paper reports the results of full-scale structural experiments to clarify the seismic performance of a skeleton-infill type house constructed by semi rigid joint frames using Akita-sugi. Both of static loading and vibration tests were performed for the case of four building stages such as 1) bare skeleton, 2) skeleton with roof and floors, 3) after inserting bearing walls, and 4) after finishing all construction. The results show that although the bare skeleton was slightly insufficient to satisfy the required seismic performance, it was successfully satisfied through the introduction of a few bearing walls. It is also shown that the building rigidity increased greatly after the perfect construction of outer and inner walls.
New moment resisting timber joints has been developed, and has been proposed timber frame structures with through beam type joint using large diameter bolts for houses. This paper presents the construction for this structures system, and the mechanical model for estimating the inelastic behavior of the moment resisting joints. The joint elements were modeled into the spring elements evaluated by one-way loading tests, and numerical resuluts using this spring model traced the bending experimental results of the joint with sufficient accuracy.
In this study, a static shear loading test of the real-size wall model and full-scale model was operated. In addition, pushover analysis using the joint model consisted of the spring elements based on simple test results was carried out, and test results were compared to numerical results. Major findings obtained from the tests and analysis are as follows; 1) According to the evaluation method of shear walls, a first floor pillar has performance of about 35kN/m, 2) The energy absorption performance of the first floor pillar depends on the transformation performance of a washer and an anchor bolt, 3) It is necessary to consider the placement of pillars to evaluate structural performance, 4) The perpendicular wall effect is not so clear, 5) By the joint model consisted of the spring elements, the elasto-plastic behavior of the frame is predictable, 6) The behavior of a real building is predictable by the elasto-plastiac analysis of a plane frame model.
By evaluating the shear strength using the seismic capacity index, the necessary shear strength from existing earthquake-resistant standard and the suitability of seismic evaluation were investigated. The results indicate the following: 1) All buildings before strengthening and buildings with Qu≧Qun after reinforcement seem to be a strength type building. Buildings with Qu<Qun seem to be a ductile type building. 2) For the buildings with Qu<Qun, the base-shear coefficient is higher than 0.4, and there is no significant difference with the base shear coefficient of buildings with Qu≧Qun. 3) Referring to the seismic strengthening plan, the seismic performance of buildings with Qu<Qun is estimated to be more than Ds=0.5 and for buildings with Qu≧Qun, it is estimated to be equivalent to less than Ds=0.5.
Responses of a high rise reinforced concrete building with 20 stories were determined subjected to earthquake and impact load due to collision of Cessna airplane. Three collision points were adopted, that is, the higher floor 19, the middle floor 12 and the lower floor 7. The impact load was obtained based on knowledge from the full-scale aircraft impact test and impact velocities for cessna was selected as two levels. Consequently, the deformation and force due to collision of Cessna airplane with impact velocity of 400km/h was 1/10 to 1/30 those subjected to design seismic waves and therefore it was proved that the collapse of the building would not occur.
Application of seismic isolation techniques for slender tall steel building requires several attentions in structural design. One is the horizontal stiffness of superstructure to maintain seismic isolation effects, and another is the uplift effect of the isolation bearing with overturning moment caused by earthquakes. In this paper, a practical design of the tall seismic isolated steel building with high aspect ratio is reported. To satisfy the above conditions, single-span moment frame structure with mega-braces on both sides are introduced, and their efficiency is discussed.
Fire resistance tests were conducted for the developed braces restrained and protected by a pair of steel channels filled with mortal, namely, steel mortal planks. Four isolated braces, which were subjected to an axial compressive load simulating long-term-load effects, were tested as specimens during fire. A set of round steel bars was provided along with both edges of core brace member so that the position of the steel channels was fixed in the standard type of specimens. Measured steel temperature histories of specimens show that filling thicker mortal, instead of round steel bars, as well as further protection covering steel channels is effective at developing higher fire-resistant performance. A static loading test in the normal temperature was also carried out for one of the standard type of specimens. The test results are compared with those of buckling-restrained braces in previous papers.