The preliminary mortar pumping has been recommended so as to assure lubrication between pipes and concrete slurry. However, technical parameters for the mortar actually employed in practice have not been surveyed so far. Research on the state-of-the art of the preliminary mortar pumping was made on the basis of 267 respondents over the country in addition to our own experiments. As a result, method, material and amount of the preliminary mortar pumping were reexamined, and the possible means to reduce it is presented.
"J-up construction system" is developed by SEKISUI HOUSE Ltd. as a new construction method of a prefabricated house. This system is as fO ows. First-roof-framing and roof-fnishing are completed on continuous footing. Second-jacks push up this roof, and the second floor is constructed Thirdpush it up again and the first floor is constructed. As every work is done on the ground in this system. Scaffolding is unnecessary and safe work is acconplished easily.
Taking full advantage of the Carbon Fiber Reinforced Concrete (CFRC), new steel-framed curtain wall panel with CFRC with uniform thickness and high dimensional stability without autoclave curing was developed, while conventional CFRC has been designed to have perimeter rib which leads to a complicated cross section, heavy weighted and complicated manufacturing. It was found that the new steel-framed CFRC curtain wall panel with a natural stone surface could be manufactured in practice, and confirmed to have sufficient performance whereby an application to building constructions was executed.
We havedeveloped the "Ultra-Lightweight Thermal-Insulating Mortar", which replace the organic-type materials. The new material is an inorganic material having a thermal-insulation performance similar to that of the organic thermal-insulating material and also has non-combustibility, high strength, high durability, high adhesion, and cracking resistance as a part of its features. We have also made possible a thermal-insulating and dewing-prevention construction method, which effectively uses the unprecedented features of this new material.
The purpouses of this paper are the development and estimation of floor tile unit for balcony. This unit consists of cushion edge ceramic tile and flexible plastic flooring tile. They are united with using organic adhesive. It is not necessary to grouting and dust portland cement in the setting tile. Using this unit, it is easy and quick to set tile on the floor of balcony. This unit has space between ceramic tile and subfloor. The water of rain can flow through this space.
To promote urban revegetation and to create comfortable living and working environments, the authors developed a unique system for the purpose of greening building rooftops and verandas without using soil. This greening system can be used to grow not only grass but small trees. This repor first describes the background to the development, then the outline of the system, and finally various achievements reached by the system, such as cooling through evaporation.
Conventional method of driving steel pipes likely cause nuisance such as noise, vibration, etc. To mitigate such nuisance, steel piles are installed in bore-holes and concrete is placed into the bore-holes. The construction cost of this pile is high. Removal of soil from boring and spoil area for the removed soil from the pile construction cause another nuisance. The steel pipe-soil cement composite piles proposed here cause less noise and vibration than driven piles, and less removed soil than bored piles. The point bearing capacity of the steel pipe-soil cement composite pile was analyzed and confirmed by pile loading test in construction sites. Test results show a high coefficient of the point bearing capacity.
This paper describes the results of earthquake response analysis of rigid frames with RHS columns allowing for deformation of joint panels. The major objective of this analysis is to investigate the inelastic response of member in the frames under strong earthquake ground motions. From the results of the response analysis, maximum story deformation anale of the frames and cumulative plastic deformation of members can be obtained. The effect of energy absorption by joint panels and the influence of vertical earthquake around motions are also discussed in this paper.
The elasto-plastic damper consisting of four spiral steel bars has been developed to use with low damping bearing like natural rubber berings and adopted to about ten seismic isolation buildings. Sufficient experiments and analysis have been conducted to qualify the damper for actual applications. However, the fatigue characteristics of the product have not been fully demonstrated. Therefore, we carried out an experimental study to evaluate mainly fatigue characteristics of the damper, and confirmed that the damper can sufficiently stand against repeated excitations which are generally used in actual design and the rapture of the damper subjected to earthquakes input can be estimated by applying Miner's rule.
A hysteretic damper installed in a K-braced frame using low yield stress steel was proposed by the authors. To investigate the mechanism, restoring force characteristics and energy absorbing capacity of the proposed K-braced frame, a lot of loading tests and numerical analyses were performed. From these results, the proposed K-braced frame was found out to be effective as a damping device. In this paper, a seismic design procedure for tall buildings, where the hysteretic dampers are installed in lower stories, is proposed, and followed by seismic response analyses to investigate optimum design parameters of the tall buildings.
A retrofitting method for existing reinforced concrete chimney and columns of building using carbon fiber was developed. In comparison with steel, carbon-fiber is a light-weight material, combining high tensile strength and durability. In this paper, the outline and the design concepts of this new retrofitting method are presented. And the evaluation methods of the maximum load of bendind and shear and the deformation capacity of column are suggested. The applications of this retrofitting method are increasing since the 1995 Southern Hyougo Prefecture Earthquake broke out.
A new base-isolation system consisting of elastic sliding bearings and laminated rubber bearings has been developed and the effectiveness of the new system is investigated by dynamic response analyses. It is remarkable that the elastic sliding bearing has the function of a damper due to the friction force of sliding. The new system makes it possible to control the yield shear force and to increase the isolated period by adequately arranging the two types of bearings. Therefore, the response shear force and the response displacement of the isolated structure can be minimized by using the new base-isolation system.
The Kansai International Airport, opened on September 4, 1994, is the world first full-scale airport built on a reclaimed land off the shore. The passenger terminal building, the main facility, is 1700 m in length and approx. 300000 m^2 in total floor area. Since the site is a large scale reclaimed land, due cares were exercised in the structural design to cope with on-going land settlement. This paper firstly outlines ground conditions of the airport island and the structural planning, then reports the seismic design for the huge structure having a large span roof frame, and the records of the structure's vibration due to Hyogoken-Nanbu Earthquake occured on Jan. 17, 1995.
A new continuous basement wall called SRC basement wall, which has steel encased reinforced concrete has been developed. SRC wall has higher shear strength and ductility than reinforced concrete wall and can serve as a basement wall, a shear wall and an earth retaining wall. This paper discribes strength test results and actual size construction test results conducted on SRC wall. An example of a large scale excavation on soft around enabled by using SRC wall is also described.
This report presents the results of the microtremor observation of the school building in Kushiro city carried out to investigate the relation between the damages of buildings occurred by 1993 KUSHIRO-OKI earthquake (M=7.8) and the dynamic soil-structure interaction effects. The response of the school buildings doesn't amplify because the natural frequencies of the buildings are higher than the predominant fequencies of the soil-structure interaction systems. This tendency is outstanding at the alluival low land sites and correspond to the damages of the buildings.
This paper discusses the vibration test of the 256m-height high-rise building built on the filled ground. This building is made by the steel structure, and it has a very slender proportion. We measured the natural period and the damping factor of the building. The measured natural period in the transversal direction is 1.09 times as the calculated one. We suppose that the sway and rocking motion of the around has a great influence in the aforementioned condition. The damping factor in this direction is 0.72%. Otherwise, the natural period in the longitudinal direction is 0.91 times as the calculated one. The damping factor is 2.91%. This condition is influenced by the finish of the building.