Long-term monitoring method based on beam-type bridge cross section neutral axis safety index

Abstract

The invention relates to a long-term monitoring method based on a beam-type bridge cross section neutral axis safety index. The method comprises the following steps: step S1: designing and installinga dynamic strainmeter assisted by a long scale distance bracket at the top and bottom of a bridge monitoring cross section, receiving and collecting obtained structure strain of the bridge; step S2: searching and preprocessing collected dynamic strain signals once so as to eliminate noise and interference in data; step S3: based on a setting threshold section, extracting an amplitude value causedby same living load and forming a binary array by wave crest values and wave trough values exceeding the threshold section, to obtain a strain response amplitude value; step S4: fitting strain distribution based on plane cross section assumption, and calculating to obtain a neutral axis index; and step S5: performing data integration on the neutral axis indexes within a period of time, analyzing distribution characteristics thereof by using a statistic model, and judging structure safety. Compared with the prior art, the method has the advantages of strong pertinence, stable long-term performance, easy popularization and the like.

Description

technical field [0001] The invention relates to the field of structural safety monitoring, in particular to a long-term monitoring method based on the safety index of the neutral axis of the beam bridge cross section. Background technique [0002] Beam bridges occupy an unshakable main position in highway bridges. With the increase of bridge service life, a large number of newly built bridges are gradually entering the "aging" stage, and various forms of structural degradation inevitably occur. It can be seen that it is urgent to carry out research on safety monitoring of girder bridges under operating conditions. By selecting reasonable and common safety indicators for long-term monitoring, the structural degradation process of the target bridge can be effectively grasped, so as to judge the safety reserve of the target bridge and carry out preventive maintenance. [0003] Bridge strain monitoring has been plagued by many problems in engineering practice. For example, th...

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Problems solved by technology

For example, the traditional strain gauge monitors the strain of structural points, the spatial resolution is too low, resulting in insufficient damage recognition rate, and at the same time affected by the disturbance environment temperature, the strain signal will drift with time, so the traditional monitoring method cannot be very accurate Reflects the structural state of the design

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