This book contains two parts. In each part, the use of carbon fiber reinforced polymer (CFRP) materials to strengthen existing, structurally deficient steel girder bridge is summarized. Two bridges were strengthened using these materials in an effort to improve the live load carrying capacity of the bridges. In one case (Part I), a bridge was strengthened using CFRP bars that were post-tensioned in the positive moment region. In the other case (Part II), a bridge was strengthened by installing CFRP plates to the bottom flange of girders in the positive moment region.