Dynamic Characteristics And Damage Detection Of Concrete-Filled Steel Tubular Bowstring Arch Bridge

The advantage of strong leap ability and easy construction make the concrete-filled steel tube arch bridge toward large span day by day. With the increase of the span, a lot of questions are following , among them the security question is particularly outstanding. Engineering structures serving in complicated environment often suffer different kinds of damages , accumulation of such damages easily results in catastrophes, so it is very important for safety of structures to detect the early damages of structures.Based on the curvature mode, the cantilever beam with multiple damaged locations was presented on the paper. Curvature mode can perfectly reflects local characteristics variety of structure. It can be obtained through series modes of structure, whose sensibility excels mode and frequency. The easiest method to obtain curvature mode is to work out the displacement mode first, then calculate the curvature mode by displacement difference method. Theoretically speaking, certain crack or damage in structure will result in reduction of stiffness in this part, which in turn increase the curvature rate and bring on mutation of curvature mode numerical value. Damage can be detected according to this principle.A new method, called flexibility curvature method, to localize the damage in structures was presented. The method is not only highly-sensitive to damage, but also able to identify the damage location in structures without baseline modal parameters. Furthermore, the method has advantages of involving a small quantity of calculation and being simple and easy in use. The damage in structures can be detected with satisfactory precision by using only a few lower modes.The wavelet transform may present the local properties of signal in time-frequency domain, and can zoom up and recognize the mutation signal of structural response under different scales. Based on mode curvature and wavelet transform, this paper presents a recognition method for structural damages. The structural mode curvature curves before and after damage are transformed in biorthogonal wavelets. The structural damage index is presented with the change and...