In smart cities, infrastructures, such as bridges and buildings, are equipped with smart sensing and actuator devices interconnected via wireless links composing a wireless sensor and actuator network (WSAN). The WSAN nodes are able to measure a variety of environmental parameters, process the sensing data locally, work in a collaborative way, make decisions on the occurrence of relevant events, and react to such events performing local control actions or sending warnings to remote operators. The unprecedented capabilities of monitoring and responding to stimuli in the physical world of wireless sensor and actuator networks (WSAN) enable these networks to provide the underpinning for several Smart City applications, such as structural health monitoring (SHM). In those applications, civil structures, endowed with wireless smart devices, are able to selfmonitor and autonomously respond to situations using computational intelligence. A decentralized algorithm for detecting damage in structures by using a WSAN. As key characteristics, beyond presenting a fully decentralized (in-network) and collaborative approach for detecting damage in structures, our algorithm makes use of cooperative information fusion for calculating a damage coefficient. The algorithm in terms of its accuracy and efficient use of the constrained WSAN resources. Keywords: Decentralized Algorithm, Information Fusion, Structural Health Monitoring, Wireless Sensor and Actuator Networks, Smart Cities I. INTRODUCTION ADVANCED detecting systems play a major role as empowering technologies to construct brilliant urban areas. In urban areas, infrastructures, such as flyovers, bridges and buildings are furnished with smart sensing and actuator gadgets interconnected by means of wireless connections creating a wireless sensor and actuator network (WSAN) [1]. The WSAN hubs can able to measure a variety of natural parameters, process the detecting information locally, work cooperatively, make choices on the occurrence of significant events, and respond to such events performing nearby control activities or sending notices to remote administrators. Applications running on top of WSAN can give a wide assortment of services to the citizens. The SHM is a rising innovation, managing with the improvement and execution of continuous and reliable monitoring frameworks for civil foundation structures using a thick WSAN. The detecting devices normally utilized for SHM applications are strain gauges, anemometers, thermistors, and accelerometers. These gadgets gather information from the monitored environment, for example, vibration estimations using accelerometers, and convey them as advanced information. In this manner, by preparing this information, the SHM techniques permit the identification, localization and degree of extent determination of harm in structures. Most of the SHM algorithms found in the literature employ centralized architectures with sensing nodes transmitting messages to a centralized entity wherein the damage detection processes effecti...