Reinforced concrete construction, one of the most popular construction method in Japan, has been developed during the past several decades as that is excellent in the fire and earthquake proof property.
Further, it was felt at the Niigata earthquake in 1964 that superiority of the earthquake resistant property of this construction was proved.
However, such several buildings as schools of reinforced concrete were severely damaged at the Tokachi-Oki earthquake in 1968 and also several hospitals etc. collapsed at the San Fernand earthquake in 1971.
In the result of these experience, the neccesity for re-examination for deformation ability of reinforced concrete structure became to be emphasized.
In this report, the experimental results of the synthetic research on ductility of reinforced columns being carried out during the past three years were summerized.

View full abstract

Shortage of good quality river aggregates and rapid increase of construction works put forward the development of untouched resources and aggregates for concrete are now produced in so many sphere such as river, sea, field or mountain. But course and fine aggregates are going to be mainly composed of crushed stone and sea sand respectively.
Although it has been considered to be dangerous for the corrosion of reinforcement to use sea sand in concrete, the great demand for aggregates in our country accelerate the use of sea sand ignoring its unknown influences. Main problems on quality of sea sand should be single grading and presence of shells and chloride. Especially the effect of chloride on the corrosion of reinforcement has not been fully examined.
The authors carried out the examination on the corrosion of reinforcement in concrete containing chloride at the Laboratory of J. H. P. C. In this research, effect of sodium chloride, calcium chloride cement content, cracks in concrete and corrosion inhibitor were examined by the accelerating test. Influence of chloride on the setting and the strength of concrete was also examined.
This report descrives the results of the examination and point out the risk of chloride in sea sand.

View full abstract

The construction work of the new buildings of the Supreme Court was one of the largest in scale carried out in this land in the recent years. Because of its gigantic scale and mass, numerous and various tests on materials and members were carried out prior to the initiation of the undertaking. Among these, reports are herewith summarized on the followings:
1. Test of shear strength of the building frame by mini-scale model.
2. Loading test (vertical) of cast-in-place reinforced concrete pile.
3. Loading test (horizontal) of an identical east-in-place reinforced concrete pile.

View full abstract