RESEARCH ARTICLE Fiber optic health monitoring and temperature behavior of bridge in cold region Feng Xiao 1 | J. Leroy Hulsey 1 | Radhakrishnan Balasubramanian 2 1 Department of Civil Engineering, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA 2 State of Alaska DOT&PF, 3132 Channel Drive, Juneau, Alaska 99801, USA Correspondence Feng Xiao, Department of Civil Engineering, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA. Email: xfeng2@alaska.edu Funding Information Alaska University Transportation Center, Grant/Award Number: 510015 Summary The objectives of this research are (a) to establish a structural health monitoring system for bridge safety evaluation that is suitable for cold, remote regions and (b) to identify the bridge responses under variations in temperature. To achieve this, fiber optic sensors with temperature compensation were selected that were suitable for cold regions. This technique allows monitoring equipment to operate far from the sensor installation site, which avoids exposing much of the equipment to extremely cold temperatures and makes a power supply more accessible. The bridge tempera- ture behavior is studied based on the real‐time field measurement data, and the relationship between the thermal loading and the bridge response is presented. KEYWORDS bridge response, cold regions, fiber optic, structural health monitoring, temperature measurement 1 | INTRODUCTION Bridge health monitoring systems can provide an early warning for bridge safety issues and are used to monitor struc- tural conditions and changes in real time. [1,2] They can also provide engineers with valuable data for asset management plans and bridge service life studies. Structural health monitor- ing (SHM) systems have been widely applied for use in bridge condition evaluation. [3–8] However, the application of these systems in cold regions is lacking, and very few quantitative studies have examined the temperature behavior of large‐scale bridges. [9] The modern transportation system has been extended to both cold and hot extremes; thus, bridge research in those areas should attract attention. The core theme of this paper is to establish a SHM system for bridge safety evaluation that is suitable for cold, remote regions and to identify the bridge response from the variations in temperature. Bridges in Alaska are subjected to extremely low temper- atures. During the first decade of the 21st century, most of Alaska experienced a cooling shift that modified the long‐ term warming trend. [10] Bridges may be located in permafrost areas, where there can be excessively deep snow, strong winds, and even seismic events. Bridges in these harsh conditions are often located in remote areas, and difficulties arise when monitoring such bridges because the harsh environment affects the reliability and durability of SHM equipment, sensors, and data communication tools. This study applied a fiber optic real‐time monitoring system for a highway bridge located in Alaskan permafrost. Based on a2‐year, real‐time monitoring project (from fall 2012 to spring 2014), this system proved that it can provide stable and reliable data for bridge evolution and is suitable for cold and remote conditions. The first part of this research provided guidelines for the implementation of bridge health monitor- ing in cold, remote regions. In addition to the effect of cold temperature and remote locations, Alaska experiences a polar day and night. This phenomenon contributes to the unusual solar radiation condi- tions in this area. The bridges are subjected to continuous temperature variations primarily due to solar radiation and ambient air temperature. Because of Alaska’ s high latitude, there is a large variation in daylight between summer and winter, which produces unusual solar radiation conditions. The effects of cold temperature, remoteness, and the polar day and night in Alaska may induce changes in conditions that are not typically found elsewhere. Received: 25 September 2016 Revised: 14 January 2017 Accepted: 14 March 2017 DOI: 10.1002/stc.2020 Struct Control Health Monit. 2017;e2020. https://doi.org/10.1002/stc.2020 Copyright © 2017 John Wiley & Sons, Ltd. wileyonlinelibrary.com/journal/stc 1 of 11