Damage detection on bridge structures based on static deflection measurements of a single point

Abstract

The principle of structural health monitoring of the bridge is the assessment of the structure performance or safety level comparing with a reference system. The most used technique is the dynamic methods which are employed to determine the structural dynamic characteristics and thereafter to locate the damages or changes in some zones of the structure. While static methods are not widely used although they are simpler than dynamic methods and also they do not require sophisticated equipment. In the last decade, some recent researches develop the interesting deterministic or probabilistic methods to evaluate the flexural rigidity or stiffness on a beam, a structure or a bridge and thus detect any damage.

The idea is to analyze the static deflections of one selected point or cross-section of a beam or a bridge with a variable position loading. The developed numerical approach uses an inverse method to solve the static equilibrium equations of a variable positions loading in the structure using the finite element method. A Matlab code is developed to solve this static inverse problem. By knowing the deflections amplitude of a selected point in the structure corresponding to several positions of a load, then the stiffness reduction factor in the bridge can be estimated.

Some examples for a beam are treated to test this new method for assessing its rigidity.