By applying the board elastic-plastic theory,the critical thickness of concrete cover is derived.

Based on concrete cover thickness and compactness measurement,construction quality of main structure is commented in Suzhou Dushu-lake Tunnel,and mass data are collected.

This paper introduces the problems in concrete cover thickness control and relevant countermeasures.

The issue of quality control of concrete protective layer thickness is done effectively,the design and construction need be combined each other.

The distribution of the radical force in the curved box girder and the influence of anti-collapse of steel area and the prestressed wire s protective layer thickness are analyzed.

Combining with theoretic analysis and numerical computing method,a formula is deduced to compute the minimum protective layer thickness of the prestressed pipeline under the disadvantageous stress.

The importance of steel reinforced concrete member protection course’s thickness and its control;

In order to know about the reinforcement protection layer thickness of prestressed concrete continuous box girders in China at present and provide the reference for calculation and test of structure,and on the basis of the field survey,a study is made on the reinforcement protection layer thickness of some prestressed concrete continuous box girders which are the background project.

By using reinforcement position detecting instrument based on electromagnetic induction principle,the steel bars protection layer thicknesses of structure are tested preliminarily when they deviate from correct position and the instrument probe is placed at different measuring points.