Damage Identification Method Research Of Frame Structure Based On The Change Rate Of Strain Mode

Reinforced concrete frame structure as a whole, and good durability, fire resistance and good benefits, has become of the most extensive form of the building structure. However, as reinforced concrete frame structure themselves larger cracking poor performance, once in the use of the process, because of the role of factors such as load, the environment, possible injuries,so that the structure can not meet the requirements of functional use, and even lead to the overall structure damage . Therefore, the reinforced concrete structure to assess whether the damage occurs, a broad and far-reaching significance, namely, the use of quantitative method determine the existence of damage, the extent of damage and the location of damage, then carrying through a general assessment of the overall situation to the structure.Structural damage detection based on the dynamic is one of the hot spots that researched by scholars at home and abroad. The dynamic characteristics of the structure itself only with its inherent nature, and the external conditions such as load and has nothing to do, by analyzing the dynamic structure inherent characteristics (natural frequency, damping and mode shape, etc.), test structure under dynamic load response , then the location of structural damage and the extent of damage , thus make accurate assessment to the safety of the structure.In this paper, using theoretical analysis, numerical simulation mutual authentication research programme. Mainly advanced a new damage identification method against reinforced concrete frame structure: damage identification method based on the rate of change of strain mode. To verify this method in the reinforced concrete structure of the overall system damage detection sensitivity of the area.The main task of this paper is as follows:(1) Introduced the damage identification technology at home and abroad the development of the current used by the various damage detection method to a simple classification, the identification methods of damage problems and improving methods.(2) Summary based on the frequency of displacement modes and modal response of several common methods to identify structural damage to the basic tenets of this and several methods are used to identify damage to the basic tenets of its comparative advantages and disadvantages, and verify its framework for the recognition of structural damage and sensitive. (3) Introduced a strain mode change based on the rate of structural damage identification method to the basic theory of the definition of strain modal concept of the rate of change, and the formula is derived from the theory identified strain modal rate index for the damage identification feasibility.(4) Reinforced concrete frame structure for the study, using the element stiffness change simulate structural damage, applicating strain modal, the rate of change of strain mode and the rate of change of strain mode based on external power to do numerical simulation of damage identification method, and compared. The conclusion to be drawn: The reinforced concrete frame structure, the using of structural damage identification method of strain modal can be judged Structure of damage, and can be used to judge damage location, but could not determine extent of damage, And need to make use of other methods judge synthetically; the mothod of rate of change of strain mode has the effect of better in damage identify, more complex components to the overall system of identification and diagnosis of the damage.