Application Report - Demolition of Rock and Natural
Stone
Rock demolition - demolition
of a hazardous rock overhang above a post office
The Job: The North American town of Pomeroy stands on the
Ohio River. Pomeroy is dominated by a steep rock wall which runs parallel
with the river and features an overhang near the top. The local post
office building, positioned directly beneath the overhang, had already
been damaged on a number of occasions by falling rocks. Customers
using the building were also at risk. As a result, it was decided
that the overhang must go. It measured about 15 m in length by about
8 m in width and was located at a height of 21 m above the river.
The requirements: Since the overhang was difficult to get at, both
from above and below, it could not be tackled with large demolition
equipment. Explosives were too dangerous. A Darda hydraulic rock and
concrete splitter was therefore used.
The solution: Observing the strictest safety precautions, workers
were roped down to the rock face, where they drilled the necessary
holes with hand-held hammer drills. The hydraulic power unit for the
splitter remained in position on top of the overhang and was connected
to the splitting cylinders by long hoselines. The workers split out
pieces of rock and dropped them into a trench. In this way, the overhang
was demo-lished quickly without any vibrations, flying stones or falling
pieces of rock.