Structural damage is a typical local phenomenon

which commonly leads to the abnormality in the local strain.Monitoring the structural damage in a distributed manner

as well as extracting the damage-sensitive feature

is an effective way to detect and position the damages in the long-span bridges.However

monitoring the distributed strain may not truly reflect the damage state of the structure due to the effect of environmental noise.Therefore

a multi-scale analysis for the distributed strain signal is proposed by wavelet transform.The proposed method alleviates the noise effects on the strain signals and averaging effect

thus determines the exact location of the singular point of the spatial signal accurately and conveniently.Meanwhile

a cablestayed bridge model with scale ratio 1:150was built in the laboratory.Both of the numerical simulation and model tests were carried out on a cable-stayed bridge model to testify the effectiveness of the proposed method.