The quality of structures has been evaluated from various standpoints. The large majority of evaluations are mainly made based on the strength, but that on the durability is necessary too.
Reinforced concrete is the most suitable material for a wide range of structures in saline environment, typically for off-shore structures. In saline environment, corrosion of reinforcing steel in concrete must be considered first to guarantee the durablity of concrete structures.
This paper summarizes briefly general problems about chloride corrosion of reinforcing steel-corrosion mechanism, influencing factors and methods of testing.

View full abstract

This describes the features of damage mainly to the concrete civil engineering structures by the Miyagi-ken-oki Earthquake of June 12, 1978 and discussion those points which may require caution in design of concrete structures referring the damage by the earthquake. The structures examined include the prestressed concrete water tanks, concrete frame aqueducts, and large cross-sectioned piers, girder seats and shoes of long span bridges.

View full abstract

For construction of Naha Municipal Hospital a new industrialized method using precast prestressed concrete members was applied. This method developed by Naito Architectural Firm is a unique system in which the skelton of structure is constructed by the use of prestressed hollow-core concrete pile as a column and prestressed and reinforced concrete beam, and other precast concrete members such as curved surface slab panel and room-sized wall panel are fixed to the frame.

View full abstract

The report describes the soundness investigated and deck repair undertaken in civil engineering structures of Kanmon Tunnel. The twenty years old, Kanmon Tunnel, a submarine traffic tunnel, has now shown many defects.
A series of investigation including concrete quality test (carbonation tests, chemical analysis, dynamic modulus determination, specific gravity test, compression test, etc.), nondestructive test (concrete solidity test by Schmidt hammer, ultrasonic wave test), water examination, investigation on the cause of stripped footway tile, and macroscopic observation on other damaged places, were carried out respectively, to obtain the data for safety control of the tunnel and to compare with those data of investigation and analysis which had been done. After analysis of these data, it was found that immediate repair was necessary at a place of the decks, and replacement of 23 square meter (7.5×3.0m) of the deck was undertaken. The results of above investigation and the repairing works are described hereunder.

View full abstract