Advances in predictive maintenance and smart technology enable structural health monitoring (SHM) of critical infrastructure like bridges. Online SHM promises to optimize maintenance, extend lifespan, and ensure safety and reliability. This practitioner reference and textbook focuses on the use of SHM in a truss bridge management system, comparing calculated displacements, strains, and accelerations with calculated results. It emphasizes the use of SHM data for predictive asset management, and its universal applicability to a 50-degree of-freedom system, irrespective of structural configurations or instrumentation techniques. It outlines the instrumentation techniques and field loading testing for static and dynamic evaluation, pre-processing of raw data, theoretical and experimental modal analysis, indicators sensitive to structural damage, and the validation of numerical models. It introduces a decision support system for structure maintenance management, conducting a capacity assessment of structural members using a detailed steel truss railway bridge case study. This book is an essential introductory book for undergraduate structural engineering students while detailed enough to introduce SHM to practicing engineers.