Long-term strain measurements of traffic and temperature effects on an RC bridge deck slab strengthened with an R-UHPFRC layer

Abstract

This paper presents the results of 28-month-long monitoring of a slab portion of the Chillon viaducts in Switzerland using strain gauges and thermocouples. This post-tensioned reinforced concrete structure was strengthened with a layer of reinforced ultrahigh-performance fibre-reinforced cementitious composite (UHPFRC). The strain gauges are used to measure stresses in the bottom layer of reinforcement bars in the slab, while thermocouples explain the behaviour of the structure due to temperature variation. The response under both traffic and thermal actions is discussed. It is demonstrated that the stress variation due to the thermal action can be as large as the response due to traffic action even in such a massive structure. Furthermore, recommendations for analysing both traffic and thermal-induced stresses are given. The commonly used simplified method for calculation of fatigue stress is shown to be highly conservative, leading to overestimation of structural action effects by a factor of four.

Monitoring der Gerbergelenke im Erhaltungsprojekt Grenzbrücke Basel

“…Monitoring helps to detect damage of structures at an early stage and provides more safety for the users of the infrastructure [1][2][3]. It is reasonable to consider only neuralgic points to reduce the amount of the measured data and provide clarity.…”

Monitoring the Prestressed Rods in the Basel Border Bridge Maintenance Project: Data Analysis during the Passage of Trucks

“…The monitoring project started in 2018 and was set up as a first step that will continue for 10 years until 2028. Further examples of monitoring infrastructures in Switzerland can be found in [ 4 , 5 ] and a general overview in [ 6 ].…”

Performance of signal processing techniques for anomaly detection using a temperature-based measurement interpretation approach

“…Effective data interpretation approaches [1,2] are key to support decision-making based on long-term bridge monitoring systems [3][4][5]. Such systems typically collect dynamic [6,7] or quasi-static response measurements [8,9], alongside environmental data such as temperature, humidity and wind. The collected response measurements, while including the effects of live loads and weather-related loads such as wind, are mostly dominated by the effects of daily and seasonal variations in ambient temperature [7][8][9][10][11].…”

“…Such systems typically collect dynamic [6,7] or quasi-static response measurements [8,9], alongside environmental data such as temperature, humidity and wind. The collected response measurements, while including the effects of live loads and weather-related loads such as wind, are mostly dominated by the effects of daily and seasonal variations in ambient temperature [7][8][9][10][11]. Bridges have also been observed to have non-linear temperature gradients that often cause thermal stresses comparable to those due to live loads [12].…”