Modal Analysis for the Rehabilitation Assessment of the Luiz I Bridge

Abstract

Dynamic testing in the condition assessment of existing bridges to support their rehabilitation and strengthening designs is becoming a common procedure, yet additional dynamic testing after rehabilitation is rare. Nevertheless, combining the results of dynamic testing before and after bridge rehabilitation produces unique and valuable information regarding changes occurred in a bridge's dynamic properties. Such dual testing would allow researchers to verify the behavior predicted at the design stage and to assess the stiffness variation, which would eliminate the need for mandatory field static testing. This article reports the modal analysis of a unique centenary steel-arch bridge that was recently rehabilitated and strengthened. The ambient vibration test conducted after the construction works is described, and the data are compared with those collected before the rehabilitation. Structural identification is completed by means of experimentally validated threedimensional (3D) finite-element (FE) models simulating both phases. The results bring to light important findings concerning variation in bridge stiffness, changes in the modal parameters, and the impact of support conditions and structure of decks in bridge dynamic properties.

Analysis of Stiffness of Clamped Joints versus Bolted Joints in Steel Structures by Means of Accelerometers and Shaking Table Tests

“…The use of natural frequency measurement from accelerometers as a means of measuring the variation in stiffness of steel structures has already been used in numerous works, such as the analysis on steel structure that had changes in its structural stiffness due to renovation processes [ 24 , 25 ]. It has also been used for the calibration of numerical models of actual steel structures and subsequent analysis of their behaviors [ 26 , 27 ], to the monitoring of the static and dynamic displacements of railway bridges with the use of inertial sensors [ 28 ], to measure the earthquake behavior of steel structures in the laboratory [ 29 , 30 ] and has also been used to dynamic assessment of masonry towers based on terrestrial radar interferometer and accelerometers [ 31 ].…”

Experimental and analytical assessment of 60 m steel truss bridge

“…Several researchers [5][6] have been conducted structural assessment and load testing in concrete and steel bridges. Old and historical bridges dominated all cases study that reported.…”

Structural integrity assessment and rehabilitating of Hercilio Luz bridge

“…Several structures are reaching their design life in Europe and America, which leads the engineers to a new concern: the need to develop rehabilitation projects aiming to guarantee structural integrity and design life increase [15]. Rehabilitation is usually an attractive alternative, once it represents between 10% and 30% of the total cost of a similar new structure for most cases [16].…”