In order to verify degradation with time for concrete wall of experimental building offered open during 31 years, the authors have investigated compressive strength, carbonation and moisture content with concrete core. As the result of several experiments, we confirmed that all compressive strengths of concrete core were higher than design strength Fc240kgf/cm2, carbonation speed for outside of walls was 2.58mm/√years, inside was 4.77mm/√years, and that the carbonation speed notably depended on moisture content of concrete surface in spite of outside or inside of concrete wall.
According to the AIJ inspection standards of steel welding using ultrasonic testing, the standard angles of the probe are either 65 degrees or 70 degrees, but there are no official rules which probe should be used. In practical use, the 70 degrees probe is often used even though it is said that the 65 degrees probe is much superior in flaw detection. We carried out an experiment to compare detection performance between “5MHz10×10A65” probe and “5MHz10×10A70” probe using AW specimen with internal flaw. As a result, we found out that there were no distinct differences between the probes.
The load of the classification process is one of big issues in the material recycling of used PVC window. This study aims to find efficient and accurate dismantling method used PVC window to recycle it. We dismantled used PVC window by the machinery and the manual methods and evaluated the quality of products using recycling materials. As a result, the large quantities disposal by the machinery process seems to be possible. But at the same time, contaminations of recycle material influenced products quality and productivity. By additional treatments for reducing contaminations in recycle PVC materials, products quality were improved.
We constructed the study from 3 steps to verify PVC sash recycling possibility. First, we confirmed the way and workload of removing PVC sash by hands. Secondly, we comprehended the workload of PVC sash and possibility of collect amount of rigid PVC in separation and selecting stage. Lastly, we comprehended influence of using recycled PVC in the consumption stage. We confirmed the productivity and formation and tested physical properties with collected recycled PVC. In each process, it shows it is possible to recycle PVC under certain amount even though there are some problems of workload.
Important in achieving a low-carbon of buildings, it is to understand the percentage of CO2 emissions at each stage of the life cycle. This paper reported on the results of the evaluation of the CO2 emissions associated with the construction of buildings by the CFP program. By using the CFP program, transparency and reliability can be obtained. Use the CFP program, to accumulate information of CO2 emissions of the various buildings, by it, and lead to the development of low-carbon construction method and material reasonable.
This paper presents results of full-scale loading tests of rocking type precast concrete curtain walls subjected to large out of plane story drift. From test results, the method to estimate the uplift behavior of the bearing support of a panel are proposed. This method extends the numerical analysis on collapse behavior of tall steel buildings. From the analysis, the rocking type precast concrete curtain walls must not reach the limit of accommodation to out of plane story drift before collapse of buildings.
In order to clarify the aging of interior finishing materials in residences, we carried out actual condition survey on stain of interior finishing in public apartment houses located in Sapporo city. According to the survey results, we found good correlation between duration of residence and brightness change as an indicator of the stain. We also observed that detergent or other cleaning methods for the interior finishing were not able to clean sufficiently after 10 years long residence.
New seismic standards for wide-area suspended ceiling have been in effect from April 2014 in Japan. In the new seismic standards, screw fastening to the connection of metal parts and a lot of bracings are required. Therefore, labor cost should increase. However, actual construction work of seismically designed ceiling based on new seismic standards is not investigated. In this study, construction of the full-scale gymnasium specimen used for the shake table experiment using E-Defense is surveyed and several construction issues are identified. Based on the construction survey, it is clarified that labor costs for construction of seismically designed ceiling need 3 times more than the labor costs for construction of non-seismic ceiling.
The expenses and the items of expenditure of exterior wall diagnosis were investigated about the building assumed for expense examination. Expense was estimated for the case where test hammer inspection or an infrared thermography inspection is used. As a result, it turned out that expense of temporary works expense forms about 30% of aggregate total costs (average), and the degradation grade is one of the factors which influence the working efficiency of investigation diagnosis. As others, the point which should be checked when a building owner requests diagnosis from an outer wall diagnostic contractor became clear.
In recent years, suspended ceilings were often damaged by earthquakes. Investigations on seismic capacity of ceilings have been conducted by some researchers. The new standard for ceilings against earthquakes requires a relatively large clearance around those to prevent collision with surrounding walls. On the other hand, there are still the needs for ceilings without clearance because of workability or room’s uses. In this paper, mechanical properties of steel furring suspended ceiling system for in-plane compression are clarified by static compression tests, using small and large scale specimen. Those properties are essential to evaluate the seismic capacity of ceilings without clearance.
The seismic performance of mud walls is decided by the mechanical characteristics of wall clay. Viscous soil is mixed with sand and fiber material such as straw for wall clay based on the experience and intuition of craftsmen. In this study, the objective is to examine experimentally the effect of the mix proportion on the mechanical characteristics of wall clay, such as cohesion and angle of internal friction. It is shown that the mechanical characteristics of wall clay can be changed by the mix proportion of sand or bentonite to wall clay.
ALC panels become the building members with necessary strength and durability by the autoclave cure. Autoclave cure of ALC takes approximately 10 h under the temperature of 180℃ and saturated steam pressure of 1MPa. It is thought that strain difference between ALC and reinforcing bar, as a result of temperature change, causes the internal stress in ALC panels. This study was conducted to clarify the existence of the internal stress in ALC panels.
In this paper, the effective seismic input at strong earthquakes to the seismic design building and to the base-isolated building in Kanagawa University is evaluated. The effective seismic input based on seismic records is compared with the simple evaluation formula. Moreover, the effective seismic input on FEM analyses of base isolated building models is evaluated about the case of various response levels. As a result, in both of the structures, the input loss effect is confirmed in the low natural periods. Furthermore, the analytical results of base-isolated building models show the influence of inertia interaction in the case of small responses.
For the wind-resistant design of buildings, it is important to understand the fluctuation component of wind. In the AIJ Recommendation for Loads in Buildings (2004), the profile of turbulence intensity and turbulence scale are specified as constant up to a height Zb, beyond which they are expressed by a power function of height Z. In the present study, the relationship between turbulence intensity or turbulence scale and observation height are discussed again, including new observation data. The scatter of observation data is also investigated.
During 14th to 16th of February in 2014, the heavy snow and snowstorm caused damage to buildings in the capital region. This sequential snowfall featured the record snow in North capital region and heavy rain after snowfall in the capital plains. Based on the hourly meteorological records, the authors proposed the snow load estimations for the remaining snow and for the snowfall and rain afterwards. According to the estimations for the annual maximum snow load records of the capital region since 1961 to 2014, it turned out that the snow load was significantly influenced by the rain load after snowfall.
An earthquake disaster prevention system using onsite seismometers has been developed since 2009. However, ground motion intensities are underestimated for far-field earthquakes, such as great subduction earthquakes. In this paper, a general procedure to improve S-wave intensity prediction for far-field earthquakes is presented. The proposed method predicts S-wave intensity (peak ground acceleration) just before arrival of S-wave, using information of P-wave intensity as well as its duration. Finally, accuracy of the proposed method is validated with simulation using observed records. These results confirmed that S-wave intensity can be accurately estimated by the proposed method.
Change in dynamic characteristics of ten super high-rise buildings during the 2011 Great East Japan Earthquake was investigated through the analyses of strong motion data. The natural periods of two RC buildings obviously increased during the earthquake, and were not recovered after the shaking. On the other hand, change of the natural periods of eight steel buildings was extremely small. Amplitude dependency of the natural periods of the two buildings was examined. The dependency of the natural periods to the response amplitudes was clearly recognized and the trends were different between before and after the Great East Japan earthquake.
Currently, it has mandatory for seismically isolated buildings to apply earthquake motions in notification since the Building Standards Act was revised in 2000. There is a possibility the notification level exceeds an earthquake motions level had been applied before 2000. Moreover, it is concerned a long-period ground motion is occur. Therefore, it is necessary to assess difference of the response performance due to these ground motions. This paper shows one example of assessing each response performance for seismically isolated buildings designed before 2000. Furthermore, it confirms if improvements by using energy balance method can enhance performance.
This paper describes the earthquake response analyses for a high-rise building considering soil-structure interaction. The object building of 67.7m height is made of steel and concrete filled steel tube. Earthquake observation data are recorded by accelerometers attached to several stories of the building, ground surface and 30m under ground. The analysis model is multi-degree of freedom system considering sway and rocking of foundation. The response analyses of the building considering soil-structure interaction corresponded to observation records.
In the Great East Japan Earthquake, many suspended ceilings were damaged and fell down. Nonstructural components such as suspended ceilings having large response magnification factors should be designed taking account of resonance. In this paper, a simple direct method for floor response spectrum is proposed and verified comparing with time history analysis. Based on the method, seismic design force on nonstructural components is determined by use of representative values of participation vectors of multistory buildings.
The objectives of this paper are to analyze nonlinear response and establish the method of evaluating the maximum response of base isolated buildings against the pulse-like ground motions. To achieve the objectives, we consider the pulse-like ground motions as the sinusoidal pulse input and propose the prediction method based on the theoretical solutions and energy balance with single-degree-of-freedom system. The proposed method in this paper evaluates approximately the maximum response against the pulse-like ground motions.
In this paper, the theoretical and approximate formulas are shown that can quantitatively evaluate the lateral stiffness and end rotation angle of laminated rubber bearings applied for column top isolation. An analytical model where a rubber bearing and a column are placed in series is used, and the rubber bearing is represented by a linear model based on Haringx’s theory. Numerical calculations are conducted using the proposed formulas in which the rubber bearing diameter and the column size considering practical column top isolation are adopted as parameters. It is confirmed that the proposed formulas can estimate the validity of the column size in column top isolation.
Based on an earthquake insurance experience, the relationship between seismic ground motion intensity and the damage ratio of wooden houses is examined. In addition, vulnerability functions are evaluated from numerical simulations, in which houses are modeled with engineering judgment based on the experts’ discussion as well as statistics of the insurance experience. The vulnerability functions have a ground motion intensity index as an explanatory variable, which are defined according to construction year and degree of loss to be covered in earthquake insurance, so as to reflect that ground motion frequency which is more correlated with damage ratio is different by structural characteristics of houses and degree of loss.
According to past researches, partial retrofitting which install steel dampers into lower stories of existing high-rise building as vibration control method for long-period ground motion is suggested. This paper reports the seismic response and response characteristics of the analysis models partial installed oil dampers or steel dampers aimed at enhancing the adaptive range of partial retrofitting. The analysis result shows effectiveness of oil damper and some points of attention to design such as the increase of deformation in the damper installed stories and the damper non-installed stories.
We study how pulse period influence response reduction effect due to base uplift. Following results are obtained. 1) We can expect response reduction effect if base uplift occurs when pulse period is nearly equal to or larger than fundamental natural period of buildings. 2) We cannot always expect response reduction effect if base uplift occurs when pulse period is smaller than fundamental natural period and higher modes upper structure and base response are not in the same phase are excited. 3) We cannot expect response reduction effect if maximum shear deformation angle appears before base uplift occurs when pulse period is much smaller.
The deep-mixing soil stabilization method creates improved soil-cement columns. The quality of the improved ground must be evaluated constantly. The conventional methods are applied a considerably long time after the completion and depend on the results of tests, necessary for reworks. The applicability of resistivity methods have been developed and studied for evaluating the quality variations of improved ground immediately after the construction. This resistivity method is based on the axial resistivity changes of a cone sensor inserted in the hardening body. As a result, it was proven to be effective in the evaluation of soil-cement columns.
In this study, two kinds of experiments were performed to clarify the appropriate construction method of foot protection part of the tip of pile. From the first experiment, it was found that infusion of the cement milk in the lower part of the model pile was very important. From the second experiment, it was shown that the increase of the quantity of infusion of the foot protection part was very effective.
SWS test is widely used as a research method to evaluate the residential sites. Advantage of SWS test is possible to evaluate the bearing capacity of residential sites. On the other hand, a disadvantage of SWS test is to determine soil and groundwater level. Suppose that if it is possible to incorporate the determination method of the soil by electrical resistivity using SWS test holes, a lot of information will be gained. As an ideal way, the electrical logging method by the electrode to the SWS test hole, is effective. Based on the above background, it was cleared that the evaluation of fine fraction content of soil was possible by electrical resistivity from the laboratory test. And the estimation equation was completed. In this study, field experiments of the six sites were performed to confirm the accuracy of the estimation equation from the laboratory test.
A practical method estimating both ground amplification and displacement is proposed for liquefied site during earthquake. This method consists of the 1D equivalent linear analysis, evaluation of liquefaction potential with an equivalent effective-stress concept, and estimation of shear modulus ratio for liquefied soil. The shear modulus ratios of liquefied soils are then estimated from inverse analyses using strong ground motion records at four sites in Japan. The estimated results lead finally to a simplified formula evaluating the shear modulus ratio of liquefied soil, which can be determined by the adjusted N-value derived from the standard penetration test.
The purpose of this analysis is to show the transition of member end loads of laminated rubber bearings with end rotations and to analyze the stress influenced by displacement and rotation angle. We analyze member end loads of laminated rubber bearings by using a formula that expanded stiffness matrix of laminated rubber bearings are simplified. In this study, analysis is performed by using a coupled model assumed base isolated buildings with inclination of pile top. In addition, we analyze the movement of the inflection point of bending moment distribution of the laminated rubber bearings.
As a significant percentage of forestation problems in Japan can be traced to young trees not being properly or selectively culled, their effective utilization contributes to maintain a forest in prime condition. The goal of our research project is to utilize effectively medium and small sized timbers as value added material. Wooden space truss system using those timbers is one important application developed by us. In this paper, pullout performance of lag screw used in joint unit of the truss system is verified through a theory of pull-out properties parallel to the grain, experiments and FEM analysis.
This paper proposes evaluation methods of the connection bending moment (M) - rotational angle (θ) relation, which changes according to the axial force of a beam (N), based on the static loading tests of the column-to-beam joints of traditional timber houses. The experimental M-θ relation was generally evaluated, although it may be small evaluated depending on the loading direction. When there was no split in a pillar, N and the influence from which M changes according to N increased in proportion to θ.
In order to maintain a large space for buildings constructed by Post-and-Beam, a large section is required. If sawed up logs or laminated wood which distribute as construction materials for housing can be used, it will be a large contribution to promote the construction of public buildings using local wood as well as stabilizing the management of lumber industry and forestry. This is a report of a full-size bending test and other tests of physical properties in order to estimate the efficiency of plywood box beams with tensile joint of flange based on Post-and-Beam Construction.
A splice joint system for timber members was proposed and its performance was evaluated experimentally. The joints are composed of a steel plate and high-strength bolts. Bending moments in the timber members are converted to coupled bearing forces in the bolted connections between the steel and timber. The bearing strength of each bolt is enhanced through the use of doubly placed steel pipe sleeves. Experiments for the connections and splice joints were conducted. The bolt connections were found to have sufficient bearing strength to allow for yielding of the steel plates as the primary failure mechanism of the splice joints.
In this study, the development of wooden shear wall with oil damper was described. The purpose of the development is to reduce a maximum story drift in 20% by the addition of two shear walls during severe earthquakes. The main flow for achievement of this purpose is to design joints resisting high shear strength, to develop and verify the high performance oil damper and to assess the shear performance and story drift using time-history analysis. The dynamic shear wall tests were also carried out to confirm the analytical study.
The restoring force characteristics and destruction properties of the different type of column-beam joint were grasped by the experiment. Since the cotter pin joint is hard to produce damage on a column, it is safer than the tusk tenon joint. Restoring force characteristics change a lot with the form and the kind of a pin. There is no difference in the restoring force characteristics by tenon length. When the restoring force characteristics were evaluated based on past research, the experimental results were evaluated in general.
This paper reports the results of study to develop potentialities of polycarbonate as structural materials for fitting type joint of traditional wooden structures. Major findings from the research are as follows: (1) Replaced wooden cotter pin with tusk tenon by polycarbonate, restoring force of joint had nearly equal as that with wooden cotter pin, and cotter pin was hardly breakage. (2) Replaced wooden oblique nuki by polycarbonate, nuki didn’t break and shear force of frame was higher than that with wooden oblique nuki in large deformation. (3) It had high reproducibility in analysis, because of heterogeneous and no anisotropic material.
Static shear loading tests of framework with a jointed column using Kanawatsugi joint were conducted and their structural performance was evaluated. The results show that, in the strong-axis direction, the maximum load and the maximum deformation angle are same as un-jointed column, but, in the weak-axis direction, the maximum deformation angle is less than that of un-jointed column. Then, push-over analysis of frameworks with mud-plastered wall was performed. It was found that, for a jointed column, the maximum load and the maximum deformation angle are same as un-jointed column, so Netsugi maintenance does not affect structural performance of framework with mud-plastered wall.
Recently, a lot of research works on the base structures have been conducted. For example, the research on the influence of the connection conditions at piles heads on the seismic response of superstructures is one of a major theme of these researches. However, ground conditions are limited and the peeling between soil and piles which occur during earthquakes was not considered in these researches. This paper studied the seismic response of superstructures considering the various ground conditions and peeling. As a result, the influence of the peeling on the response was found to be remarkable particularly when superstructures are elastic.
Numerous reinforced concrete super high-rise buildings have recently been constructed. In order to build even higher buildings and simultaneously minimize the cross section of columns and increase the span, reinforced concrete columns using Fc150N/mm2 super high strength concrete are being developed. No adequate studies have, however, yet been made of the structural performance of reinforced concrete columns against shear failure. In this study, three types of Fc150N/mm2 reinforced concrete columns that were reinforced conventionally, with steel fiber and plate jacketing were subjected to static loading to identify structural performance and evaluate shear strength.
Because of its high processing accuracy, laser cutting is capable of not only contour cutting but also hole drilling. However, notches generated by welding loss at cutting start positions as well as hardening in the vicinity of the hole due to heat are negative characteristics of laser drilling. On the basis of a high-strength bolt friction joint experiment, which aims at applying a laser processing hole to a high-strength bolt, we report a slip coefficient and maximum tensile strength for laser drilling, which are equivalent to those of ordinary drilling.
In surveys on the damage of buildings caused by the 2011 Tohoku-Pacific Ocean earthquake, it was reported that damages such as cracks were detected in a number of lead dampers used in seismically isolated buildings. After investigations of the damaged dampers in detail, it was confirmed that these cracks were generated by accumulation of small-amplitude loading like middle-small earthquakes or winds rather than by large-amplitude loading like large earthquakes or strong winds. From this background, fatigue characteristics of a lead rubber bearing (LRB) under repeated small-amplitude were evaluated by cyclic loading tests of scaled models. The shear-strain amplitudes of the testing were 1%, 10%, 20%, and the maximum number of the cycles for each level of amplitude was 4000000, 59000, and 17000, respectively.
The story drift angle has been recognized to have a close relationship with damage in the building. Several methods have been proposed using displacement sensors or corporative marker. However, they are costly. In this paper, a method using optical flow to estimate story drift angle is proposed. This method is simple and less costly. It was verified that the story drift angle was accurately obtained from the simulation tests.
U-shaped steel damper is a type of commonly-used damping device for seismically isolated structures. After earthquakes, it is necessary to quickly evaluate the damage of U-dampers to find out if they need to be replaced. However, current evaluation method can only be used when the deformation history of the U-damper is known. In this paper, a damage evaluation method based on the area covered by the recorded orbits of the base-isolated stories is proposed. The damage of the damper during aftershocks is proved to be small enough to be ignored. The conclusions of this paper are checked against experimental data.
Authors have been developing computational software for the life-cycle design of structures through utilization Genetic Algorithm. Present paper proposes application examples of the actual building in planning phase as a step for practice use. For practice use, calculation and setting method for numerical model as well as design parameters have been improved. The obtained results can be considered reasonable showing useful knowledge about structure in solution space. The two-step usage method of software on the basis of the knowledge is proposed, which can be said much more suitable for practical use.
This paper compares the temperature and velocity predicted by Large Eddy Simulation (LES) with those by the experiment, in order to grasp the effectiveness of the smoke flow reproducibility by LES. Tunnel scale characteristics of the smoke flow and the temperature are also examined with the macro evaluation model based on the LES results. It is shown that LES results correspond well with the experimental values, and that the tunnel scale characteristics can be described by the macro model. In addition, Cumulative Thermal Value was used as the thermal index of evacuation safety in the tunnel fire.
In this study, the fireproof performance of high-density ALC floor panels was investigated. High-density ALC panels designed in accordance with the allowable stress under the design condition of 2,500mm less length, 3,500N/m2 less live load and 100mm more thickness have the fireproof performance which is necessary for Building Standards Act as a floor panel of fireproof construction. The fireproof performance of the floor structure using the high-density ALC panel can be evaluated by the parameters of the maximum load, the maximum length and the lowest thickness obtained by the fireproof test.
In an open-plan elementary school, a field study to make better use of sound environment was conducted by collaboration between school teachers and researchers in architecture. For the conservation of sound environment in the open-plan classrooms, workshops were held and handouts for children to understand the manners required to prevent noise problems were produced. Besides, educational practice to take advantage of various room reverberations in the school was suggested and two types of learning program were performed. In this report, the processes and effects of the activities are presented.
Impact source be used in the rating of floor impact sound are the tapping machine and the tire. L grade is generally using single-number quantity. However, the ball was introduced for standard heavy weight impact source in JIS A 1418-2:2000, and single-number quantity by the A-weight floor impact sound level has been studied. In this report, we compared each single-number quantity. As a result, there is no correlation A-weight floor impact sound level using the boll and L grade using the tire.
The purpose of this study is to develop a method for “Zone-controlled” blind using radio frequency identification in an open-plan office with a large window. A numerical simulation and a subjective experiment were carried out to identify how glare is affected by the following three variables: the distance between the facade and the observation point, the viewing angle and the width of the blind control zone. The results showed that independent “zone-controlled” blinds could reduce the discomfort glare as much as “globally-controlled” blinds when the control-zone is greater than 100 degrees of arc in the subject’s horizontal field of view.