I-95 Near St. Augustine, FL

The Problem

The bridge, located on I-95 over SR-206 near St. Augustine, Florida, is 119 ft. long and has three simple spans. The bridge was opened to traffic in 1965 and was designed to carry two lanes of AASHTO HS-20 loading. The main span is 42 ft. long and consists of a 7 inch thick concrete deck on seven AASHTO Type II pre-stressed concrete girders spaced at 6 ft. centers.

The bridge was severely damaged when a vehicle transporting timber logs impacted the girders. The collision resulted in extensive damage to several girders.

The exterior girder of the bridge sustained the most damage. The girder exhibited severe shear cracking, section loss and damage to three pre-stressing strands. The strands were exposed in the location of impact for a distance of approximately 20 feet. Equally important to the loss of pre-stressing force was the change in section caused by the spalling of concrete in the web and the severe cracking along the bottom flange of the girder.

Load testing evaluation revealed significant reduction in flexural and shear capacities of the bridge requiring immediate attention. The severity of the damage and the location of the bridge created an emergency situation. The option of closing a traffic lane in order to replace the exterior girder was not feasible due to the heavy traffic conditions on I-95.

An innovative alternative to conventional repair techniques was to use a composite carbon laminated system. The MAS2000 Fiber Wrap System proved to be an economical and valid solution.


Views of Damage to pre-stressed Concrete Girders

The Solution

Restoring Concrete

The MAS2000 Fiber Wrap System was considered to be the best option for the situation. The repair system was designed to restore the strength of the girders to the original design level.

The damaged girders were analyzed using a non-linear finite element program developed by SDR engineers. The program was developed and calibrated through extensive laboratory and field testing and yields extremely accurate results. The results of the analysis were used to design the optimum restoration solution.

The cross sections were first restored to the original shape using high quality concrete capable of achieving full strength within 24 hours. The section restoration was followed by surface preparation according to SDR specifications. The specially designed composite laminates were then applied to the concrete girders over a distance of 25 ft., resulting in complete restoration of the girders.

The rehabilitation crew was able to apply the system and return the bridge to traffic in less than three days without disturbance to traffic on I-95.

The MAS2000 Fiber Wrap System provided a rapid and easy repair solution.

The original appearance of the structure was restored and enhanced by painting the laminates with a specially designed ultraviolet (UV) coating.

Sections

Load testing and inspection proved the structure to be sound and the original load rating for the bridge was maintained.


Application of MAS2000 Fiber Wrap System