Instant Bridge

The State Highway Administration plans to use a relatively new technique to replace two 63 year old bridges that carry West Nursery Road over the Baltimore Washington Parkway near the airport. According to an article today in BizWeekly the replacement spans will first be constructed in the median strip of the parkway and then moved “into place using specialized equipment called self-propelled modular transporters (SPMTs). The multi-axle, multi-wheel hydraulic SPMT can transport extraordinarily heavy loads.”

Okay, “instant” may be a bit of an exaggeration but the process is quicker and apparently safer than building the bridges in place.

“After building the 76-foot-long, 215-ton bridges in the median, crews will literally roll them into place at about four miles per hour,” said SHA Administrator Melinda Peters. “This innovative construction project is safer for drivers and crews because the work zone is out of traffic and the duration is shorter by nearly nine months.”

It’s a pretty cool process as evidenced in this animated video of a bridge replacement project in Utah.

The work is slated to be completed over two weekends this fall.