The proper Work Breakdown Structure (WBS) is very important in project planning so that deliverables and project work can be broken down into smaller components, more easily to construct and costs can be better controlled. Construction of concrete precast bridges is the dominant type of bridge construction used in Indonesia because it provides many advantages over the other types of construction. Although the project is unique, the works on the construction of Precast bridges and their elements are relatively similar, so they can be standardized and used as a basis for project control. This study aims to create WBS Precast Bridge construction standards and identify risk variables on the work packages, activities and resources on the construction of concrete precast bridges for improved project cost performance. This study provides results that the WBS standard of concrete precast bridge construction consists of 6 levels, with 13 dominant risk variables and 5 risk response recommendation groups against project cost estimates as the development of WBS standards.