Hole Rescue #2

In the “Hole Rescue” part 1 blog I talked about an alternative tactic for lip safety at trench incidents where ground pads can not provide adequate protection.  We call the tactic a Lip Bridge.  The pictures below shows scenes from a trench rescue in Bay City, Michigan. This trench (repair hole) was about 6’ wide, 9’ long and 16’ deep.  Three of the four walls had sloughed creating large overhangs.  More than 15,000 pounds of unsupported soil hung ten feet above the victims head.  Stepping on the lip would have surely caused the overhangs to break off and land on the victim.  Traditional ground pads would have distributed the weight (distributed versus  concentrated loading)  of the rescuers but would have still had the load directly on the overhangs.  Our goal was to transfer  the load away from the overhang areas to solid ground.

Photo #1

We accomplished this goal by creating a bridge system.   The foundations for the bridge were 4×4 cribbing which was set on solid ground about 5’ away from the lip.  The cribs elevate the first bridge (fire service ladders) which span the short walls of the trench.  Other ladders or lumber can be used to span from the short wall bridges at each end of the trench.  The result is that rescuers can install shoring material on all four sides of the trench without ever loading the lip.

 

Note:  At the Pompano rescue I don’t see this type of cave-in pattern (slough-in) however, beach sand is very susceptible to cave-in caused by surcharged loads on the lip.  A lip bridge may have made thing safer.

Photo #2

The patient was a city utility worker with more than 30 years on the job.  When I arrived he was buried to his armpit level with his arms also buried.  This picture shows our initial digging effort which freed his arms and relieved pressure on his chest.  At this point we have him on oxygen with an IV in place.  We had one of our USAR task force Medical Managers (E.R. physicians) on scene and as the incident progressed crush syndrome considerations were examined.

Photo #3


This photo shows the completed shoring system.  “Cross shoring” was needed to protect all four walls.  Giant low pressure airbags from a tow truck company were used to manage the voids created by the slough-ins.   Supplemental shoring was installed as we dug the victim out.  He was standing when the cave-in occurred so we had to dig more than five feet below our initial panels and shores.

Time Frame:
Primary shoring (protect the victim) was completed within 40 minutes of our arrival.  Secondary shoring (completed system) was done in less than two hours.  A vac truck was used to help dig the victom out of the moving/sandy soil.

 

Speak Your Mind