All weathers temporary roof system, using three-step telescopic supports roof, was developed to cover workplaces with a roof, and to shelter operations from rain and snow. By carrying out an on site application trial, it was found that because of the protection provided by the sysytem, work could continue even during rain, leading to a considerable increase in productivity. It was also found that the system gave an even greater protection from direct sunlight than was initially anticipated, resulting in an overall improvement of the working environment.
Test methods for characterizing and evaluating waterproofing membranes were first described. They are a water-tightness test and eight performance tests such as static puncture resistance, dynamic puncture resistance, resistance to cyclic fatigue, stability of joints between roofing membranes, resistance to sliding on vertical walls, stability at corners in substrate, resistance to high winds and resistance to blistering. Then, we tested four types of roof waterproofing systems, including 4 built-up systems, 10 torch-on systems, 22 sheet-applied systems and 5 liquid-applied systems. It was found out that each systems has different levels in perfomances. On the best of the results, we discussed the character of each waterproofing systems.
To increase holidays and improve working environment, construction methods not effected by bad weather are worthy of attention. In many of existing methods, it is usual for a workshop not to get wet that a temporary or a practical roof is constructed first, and lifted up or jacked up. In the method reported in this paper, external aluminum panel walls set to hide equipments on the roof are assembled on the ground and slided up as steel frames are constructed. These walls are also useful for workshop not to be disturbed by winds in addition to rain.
Light Weight Stone Veneer Curtain Wall using elastic adhesive and mechanical ties to attach stone to a deck plate frame was developed. Prior to tral manufacturing, elastic adhesive durability, silicone infiltration from elastic adhesive to stone (causing contamination) and mechanical tie fatigue properties were thoroughly tested. Trial manufacturing of spandrel curtain wall panels revealed good productivity and economical merit. Wind resistance test showed these panels to satisfy external wall performance requirements. There are many applications for this curtain wall system.
We applied super workable concrete to concrete construction by upside-down method for the first time in this country. We made the best use of characteristics of super workable concrete that is superior in concrete flowability and stability and studied systematically concrete construction by upside-down method. As this result, we made it clear that this method is very economical from the points of less honeycomb, void and sand streak and small space at horizontal construction joint and furthermore rationalization of construction and elimination of laber.
To provide facility management service, the Building Maintenance Planning System, a comprehensive expert system supporting inspection and diagnosis of building elements, rehabilitation planning and proposal had been developed and is being introducing. By using the system, current deterioration level and deterioration projection of inspected building elements are diagnosed and appropriate renovation specification are selected automatically. And finally, a rehabilitation proposal with renovation cost and performance recovery information is prepared for building managers. The concept and main structure of the system are based on accumulated results of research and development in building maintenance area conducted in NTT for last forty years.
In this paper, design for installation of concrete form, concrete casting test and calculations of heat insulating performance were carried out in order to develop the heat insulating permanent form made of scraps of magnetic tapes. As the results, following conclusions could be drawn, (1) The panels could be designed for concrete form using lateral pressure described in JASS5. (2) The heat insulating performance of the panels satisfied the specification of insulating structure on the Government Housing Loan Corporation of Japan.
The basement of a sewage farm we mentioned here consists of 21 RC water-tanks with high-density reinforcement and high stories (5 m and 6.3 m). To get a good watertightness and to minimize the number of construction joints, we placed super workable concrete of about 600 m^2 in a day into walls and columns. In advance of construction we carefully made the best plan of placing division and placing order. As a result, a quality of the structure was satisfactory and a remarkable effect was obtained in productivity improvement, such as reduction in the number of workers and in the term of construction.
In a study using seven water-soluble polymers (two cellulosic polymers, three synthetic resins, and two natural gums), a nonionic cellulose ether was found to be the most suitable polymer as segregation controlling admixture for high-fluidity concrete. The evaluation was carried out by measuring the viscosity of cement paste, the deformability and resistance to material segregation of cement mortar. In addition, the concrete containing the nonionic cellulose ether had a superior fluidity and high resistance to material segregation, and its durability (shrinkage, freeze-thaw resistance and neutralization) was equivalent to that of ordinary concrete with the same water cement ratio.
Unitization of members is being carried out at a high rise building construction site to enhance work safety and tower cran's lifting efficiency. This paper focuses on the improvement of one such system, unit floor method. Main subjects include development of pre-application of semi-dry fireproofing and site automation of unit floor fabrication yard. These improvements considerably enhance efficiency of unit floor fabrication and of work at each floor after installation compared with the conventional unit floor method.
Green Concrete is a concrete on which plants directly grow. It consists of a continuous void concrete, a weter retentive material in the void and thin soil layer sprayed on the surface. The continuous void concrete is made of single sized crushed stone and low alkaline cement paste. Chopped peat moss containing fertilizer is used as the water retentive material. Seeds are mixed with the soil germinate. The optimum compressive strength of the concrete was approximately 10 to 15 N mm^2 when the void ratio was approximately 30 percent. It was demonstrated that herbaceous plants sufficiently grow on Green Concrete.
This paper describes a new construction method by which the top floor is erected first, then the other floors while pushing up the top floor by the height of the new floor one by one with oil jacks, to construct a building. This working method was tentatively applied in 1990, and satisfactory results were obtained. So, further improvements were made to the construction method and facility, and were applied in 1994. This paper first introduces the concept and working procedure of this process and then its application to a multi-story office building.
In the field of building materials, high fluidity concrete has been developed. High fluidity concrete consists of various materials and many combinations of these materials are possible, but the consistency and workability of these concrete is not clear yet. So, in this paper an investigation was made on the change of concrete properties through pumping, fluidity and pumpability, by placing four kinds of concrete into real-size wall and column mould using pumping method.
A damage tolerant structure consists of a primary structure such as beams and columns, and seismic members. The primary structure remains within the elastic strain range during an earthquake, and the seismic members absorb seismic energy. The experiment has shown that the realization of structures with high energy absorption is possible through early plasticization of seismic members. In accordance with this concept, we designed a high-rise building. The seismic members become plasticized even at the moderate seismic excitation level but not to the extent that repairs become necessary. At the large seismic excitation level, seismic members are extensively plasticized. Therefore, after a large earthquake, seismic members are replaced as required.
PHC nodular piles are considered to be a favorable foundation option for low to medium-rise buildings at deep soft ground sites. A comprehensive load test program was undertaken to evaluate the bearing capacity of these piles in different site conditions. A convenient and adequate approach to evaluate bearing capacity of PHC nodular piles is proposed based on the test results.