| This report serves three purposes: (1) to determine the best suitable alternative and the practicality of a stress-ribbon, (2) to learn about the design of stress-ribbon bridges, and (3) understand the effects of prestressing on stress-ribbon bridges. This report describes the design requirements, architectural and structural design, and static analysis and structural behavior of the bridge.;A stress-ribbon bridge was chosen as the best bridge design for Popolopen Creek after evaluating six other alternative designs. The alternatives included trusses, arches, and cable supported structures. Factors that attributed to a stress-ribbon's appeal include its minimalist appearance, case of construction, low cost of construction, low environmental impact, and minimal long-term maintenance.;The stress ribbon structure being proposed will be a total length of 336 feet between abutments and will accommodate pedestrians or a maintenance vehicle. The stress ribbon will be an assembly of 21 precast concrete segments suspended on bearing cables and prestressed with post-tensioning tendons. The bridge was designed in accordance to AASHTO guide specifications for pedestrian bridges along with the appropriate steel and concrete codes from RISC and ACI respectively and complies with all requirements stated.;SAP2000 structural software was used to statically analyze a model of the proposed structure and to investigate the effects of prestressing the deck. The model verified the functionality of the bridge in terms of deflection and load carrying capacity. Prestressing of the deck also shows increased rigidity of the deck and reduction in maximum deflection but resulted in increases to external lateral forces. Varying of tendon eccentricity and prestressing forces also revealed other behavior trends in stress ribbon bridges. |
