I-95 North of West Palm Beach, FL

The Problem

The bridge is located on I-95 near West Palm Beach, Florida and consists of four simply supported spans. Each of the two middle spans are 55.5 ft long and consists of nine AASHTO Type II pre-stressed concrete girders spaced at 5.75 ft. on centers. The girders support a 7-inch thick concrete deck carrying three lanes of AASHTO HS-20 loading. The bridge was opened to traffic in 1967.

Several girders sustained severe damage due to repeated collision by heavy vehicles with heights exceeding the clearance limit. The girders exhibited localized damage, pre-stressing loss, flexural cracks, concrete spalling and severe shear cracking. Also, cracks extended horizontally along the interfaces between the web and both the top and bottom flanges.

Load testing of the bridge revealed the extent of the structural damage. It was determined that two girders lost up to 30% of their strength and required immediate attention.

The size and type of cracks caused concern with regard to the fatigue and shear performance of the girders. Conventional repair methods were considered; however, this would require the closure of two lanes under the bridge and one lane on I-95. This solution was undesirable due to the heavy volume of traffic both on I-95 and on the road under the bridge.


Views of Damage to Flanges of the Girders

Alternative innovative solutions were required to perform this repair effectively and to minimize the amount of time without disrupting traffic.

The MAS2000 Fiber Wrap System was chosen as the preferable method of repair. The estimated total time for performing the repair was 24 hours over a six-day period. The work was performed during the hours of 11:00 AM and 2:00 PM to avoid periods of heavy traffic. The MAS2000 system also represented the most economical method of repair.

The Solution

Restoration of Concrete

The MAS2000 Fiber Wrap System involved the application of carbon/epoxy laminates capable of resisting applied fatigue stresses and of restoring the girders to their original design strength. The girders were analyzed utilizing 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 girder cross-sections were first restored to 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 MAS2000 Fiber Wrap System was then applied to the girders over a distance of 20 ft., resulting in complete restoration of the girders.

Work was performed during daytime hours without the shutdown of any part of I-95, and with only minor interruption to local traffic. Total time for rehabilitation took less than 12 hours during a three-day period, which was half the amount of time originally expected.

Sections

Application of MAS2000 System

One week after completion of repair, a specially designed coating was applied to the structure to provide ultraviolet (UV) resistance and improve aesthetic appearance.

Load testing was performed on the bridge shortly after the completion of repairs. The results of the tests indicated that the girders were restored to their original design strength.

The bridge was rehabilitated in 1993 and periodic inspections indicate no signs of any structural deficiency or deterioration.

The MAS2000 Fiber Wrap System proved to be economical, quick and easy to apply.


Repaired Girders Prior to Final Finish Coating	Load Testing of Repaired Bridge