743 DeJong, Schooling and Viggiani ISBN 978-0-7277-6466-9 https://doi.org/10.1680/icsic.64669.743 Published with permission by the ICE under the CC-BY license. (http://creativecommons.org/licenses/by/4.0/) International Conference on Smart Infrastructure and Construction 2019 (ICSIC): Driving data-informed decision-making STRUCTURAL HEALTH MONITORING OF AN INTEGRAL BRIDGE S.A. Skorpen 1 , E.P. Kearsley 1 and C.R.I. Clayton 2 1 Department of Civil Engineering, University of Pretoria, Pretoria, South Africa 2 Department of Civil Engineering, University of Southampton, Southampton, United Kingdom ABSTRACT This paper gives an overview of almost three years of monitoring data obtained from instrumentation installed in a 90m long reinforced concrete integral bridge in South Africa. The main objective of this structural health monitoring project was to assess the effect of environmental factors on integral bridge abutment movement, with specific focus on thermal effects. The data obtained from the instrumentation enables designers to compare real and assumed effective bridge deck temperature, earth pressure and abutment movement. Analysis of the data seems to indicate that the deck cross section shape (defined as the ratio of surface area to cross sectional area) has a significant effect on the effective bridge temperature, abutment movement and earth pressure. This hypothesis was tested using the preliminary SHM data, and conclusions were drawn as to whether an increase in deck thermal inertia might be used to mitigate the effects of increased deck length. Notation L = Bridge deck length; R = Horizontal reaction force on integral bridge footing; T = Deck temperature;  = coefficient of thermal expansion 1. Introduction Integral bridges are favoured by bridge authorities and road agencies because they eliminate the use of bearings, providing a simpler form of construction, with reduced maintenance costs. Most existing integral abutment bridge (IAB) research focused on the behaviour of IAB substructures, and as a result, the design limit states considered by many road authorities are largely based on substructure considerations, usually as a function of soil properties at the abutment and pile foundation. This focus has been motivated by the significant increase in substructure demands for integral construction. Integral bridge behaviour during construction and service life however remains poorly understood. As integral bridge decks become ever longer, and working environmental conditions become harsher, there is a need for monitoring and the development of design tools to support the use of this type of bridge. Recent research indicates that a better understanding of the bridge deck behaviour can benefit integral bridge designers. LaFave et al., (2016) has shown that integral abutment construction also affects superstructure behaviour and demands, and that superstructure properties can directly influence on substructure behaviour. Parametric studies by Kim et al., (2010) indicate that the bridge deck factors with the most significant influence the structure are the deck length and coefficient of thermal expansion of the deck material. England et al., (2000) shows that smaller bridge deck thermal movements results in lower lateral earth pressures and reduced settlement of the fill behind the abutment. Understanding the effect of changes in deck temperature is thus crucial to the efficient design of durable integral bridges. While temperature effects in conventional jointed bridge structures are often negligible (as the thermal movement is accommodated at the expansion joints), integral bridges cannot be designed without taking thermal movement into account. Work done by Elbadry et al. (1983), Emerson (1976) and Black et al. (1976) on reinforced concrete decks shows that the changes in effective bridge deck temperature are dependent on the ratio of the deck cross sectional area to deck width. Thus the response of any structure to environmental climatic variation is dependent on the structure geometry and material. 2. Bridge Deck Temperatures Changes in the ambient shade temperature and solar radiation result in changes to the bridge deck temperature. In reinforced concrete decks, the low thermal conductivity of concrete and a variation in the depth of the deck across its width has a significant effect on the temperature variation in the deck. The temperature variation in the deck affects the effective deck temperature, which governs the change in length of the deck due to temperature variation. The effective bridge temperature is defined by Emerson (1973) and Roeder (2003) as the weighted average bridge temperature. Downloaded by [] on [01/07/20]. Published with permission by the ICE under the CC-BY license