The objective of this research project is to investigate the performance of a full-scale High Performance Concrete (HPC) bridge.
In October, 1996, FHWA entered into a cooperative agreement with NCDOT through which funding was provided for a joint project between NCDOT and North Carolina State University to instrument the HPC bridge on US 401 and monitor its behavior. The project included the following four primary tasks:
Specification of expected properties and associated quality control procedures for HPC concrete produced in typical plant and field conditions, including testing of specimens taken from full scale batches. Requirements regarding production and quality control of HPC materials were included in the special provisions for the project.
- Internal and external instrumentation of four girders at the plant, and monitoring of temperature and behavior of the girders at the plant. Work included evaluation of transfer lengths of strands at both ends of at least two girders.
- External instrumentation of the same four girders after erection at the site, as well as instrumentation of cast-in-place connections between girders. Following instrumentation, performance of the bridge was to be assessed by monitoring short-term behavior through the period immediately following opening of the bridge to traffic.
- Long-term evaluation of the structure.
This project was begun as Research Project 1997-08 ""The Implementation of HPC in a Set of Dual Four Span Bridges on US 401 in Wake County"".
By using HPC, designers can take advantage of not only its structural efficiency but also its enhanced durability. The investigation will focus on the following goal: validating analytical models assumed during design, with a specific emphasis on girder stiffness and deflection calculations, creep and shrinkage effects, and thermal effects.
In order to accomplish these objectives, it is proposed to conduct a live load test on the fully instrumented bridge after it is completed, but prior to its opening to traffic and to follow this with short and long term monitoring for thermal and traffic load effects. Additionally, after the bridge is opened for a full year, a second live load test is proposed to assess if there is any significant change in performance.