Common use of Conceptual Design Phase Clause in Contracts

Conceptual Design Phase. It is assumed that Natural Bridge Road will be closed at the structure during construction. Staged construction or a temporary bridge bypass will not be used. A signed detour using public streets will be provided to maintain vehicular traffic. Sidewalks do not extend across the existing structure therefore pedestrian access will not be maintained during construction. A. Hydraulic Analysis/Design 1. Perform a hydraulic study and analysis for the 15-, 25-, 50- and 100-year event floods for the existing, natural, and proposed conditions (various options) at the structure along Cowmire Creek. 2. Summarize hydraulic results for each option. B. Road & Structure Option Review 1. Review proposed Natural Bridge Road vertical and horizontal alignments. It is anticipated that existing horizontal and vertical alignment will be closely matched, and that replacement structure/roadway will overtop during flood events, similar to existing. 2. Review conceptual structure alignment and replacement types to include multi-cell culvert and single or multi-span solid slab concrete bridge options. Voided slab or prestressed box beam superstructures are not recommended due to overtopping conditions. Prestressed concrete or steel beam/girder and slab superstructure would require a significant increase in superstructure depth with associated grade raise. 3. Prepare limited concept drawings, as needed, to illustrate various options. C. Prepare comparative conceptual cost estimates and pros/cons for viable options. D. Perform QA/QC review of Conceptual Design information. E. Meet with the City to review conceptual options. F. Obtain City approval of preferred option before proceeding to Preliminary Design Phase.