CHARLESTON, SC (WCSC) - An accumulation of rainwater from extreme and unexpected thunderstorms is being blamed for the July tarp failure on the Don Holt Bridge.
SCDOT has completed its final review of the report on the tarp that fell on the Don Holt Bridge on July 19.
The report was conducted by a licensed professional engineer representing Applied Building Sciences (ABS).
ABS's report indicates the weight of the rainwater on the tarp most likely caused the tarp support chokers to fail. The chokers were used to support the suspended platform beneath the bridge's superstructure.
Maximum wind speeds at the top of the bridge were likely to have reached 58 mph on the day the tarp fell, according to certified meteorologist Lee Branscome, Ph.D.
In addition, 1.68 inches of rainfall was reportedly recorded within five miles of the bridge between 5 and 6 p.m., the same timeframe the tarp fell.
The report concludes the primary load that resulted in the failure was caused by rain and not the winds.
Reports further state Eagle Industrial Painting, the contractor hired to paint the bridge, did not have access to the tarp during the day to monitor the rainwater because SCDOT only authorized lane closures at night.
However, while SCDOT had not authorized a permanent daytime lane closure during the day while the bridge was being painted, SCDOT says in a news release they would have authorized the lane closure for tarp repairs or de-watering had it been requested.
Among the motorists whose cars were damaged by the tarp, Eagle Industrial Painting reports 12 car owners filed claims. 10 of those car owners have received payment.
SCDOT and Eagle Industrial Painting continue to evaluate ways to reduce or eliminate the possibility of another tarp failure.