A Damage Analysis of Steel-Concrete Composite Beams Via Dynamic Methods: Part II. Analytical Models and Damage Detection

Abstract

This paper is the second part of an experimental-analytical investigation on the dynamic behavior of damaged steel-concrete composite beams. In the first part of the research, we presented and discussed the experimental results of a comprehensive series of dynamic tests performed on composite beams with damage in the connection. Experimental observations suggested the formulation of a composite beam analytical model, where the strain energy density of the connection also includes an energy term associated to the occurrence of relative transversal displacements between the reinforced concrete slab and the steel beam. A comparison with experimental results shows that the model enhances accuracy in describing the undamaged state of composite beams and that it is also appropriate to accurately predict the dynamic behavior under damaged conditions. A damage detection technique based on the measurement of variation in the first flexural frequencies was then applied to the suggested model and gave positive results.

A variational approach for an inverse dynamical problem for composite beams

“…In the following applications we shall refer to the specimen T 1P R of steel-concrete beam analyzed in the experimental study [5]. In particular, the case of a damaged composite beam having initial constant elastic and inertial properties will be closely examined.…”

“…The numerical algorithm is based on the complete form of the differential of J determined in Theorem 3.1. The identification technique is tested on dynamic test data coming from a real specimen of steel-concrete composite beam studied in [5]. A more comprehensive study of the proposed numerical algorithm for solving this inverse dynamical problem will be presented in a forthcoming paper.…”

“…Here "d" means the physical dimension. Table 1: Physical constants of the steel-concrete beam T1PR [5]. …”

“…A steel-concrete composite beam is obtained by connecting two beams, a metallic one and a reinforced concrete beam, by means of small metallic elements (connectors) which are welded on the top flange of the metallic beam and immersed in the concrete, in order to hinder sliding on the concrete-steel interface, see see [5]. Under the assumption that the system is at rest at t = 0, that is | x=L = 0, u 1 | x=0 = u 1 (t), u 2 | x=0 = u 2 (t), v 1 | x=0 = v 1 (t), v 2 | x=0 = v 2 (t), ∂v 1 ∂x | x=0 = ϕ 1 (t), ∂v 2 ∂x | x=0 = ϕ 2 (t).…”

Condition Assessment of Shear Connectors in Slab-Girder Bridges via Vibration Measurements

“…As a matter of fact, examples of condition assessment of shear connectors are very rare in literature. To the authors' best knowledge, only one study has attempted to detect the damage in connectors between steel-concrete composite beams in laboratory Dilena and Morassi 2003). In their study, steel studs were used as connectors to link a concrete slab and a steel girder.…”