Limitation of construction time in each day was written in law and
it is from 8:00a.m. to 6:00 p.m.
When there is heavy rain or typhoon signal no.3 or above, all site
works should be terminated until the weather become fine again.
Safety Measures
When worker go down to ther bottom of caisson towork, there may be
methane gas or other poisonous gas. In order to provide sufficient fresh
air and take away the poisonous gas, a compressor is used to pump the air
down to the bottom.
Besides, a water pump is also set up to pump away any water which may
cause danger to worker.
Before further excavation is continued, a supporting frame about 2m
high is erected on the ground surface above and across the caisson opening.
This frame acts as a support for up loading of the worker from the bottom
level of caisson. During construction, worker is provided with a ' life-string
', an alarm switch on the alarm and sufficient lighting. Sufficient lighting
can enable the worker to visualize the condition inside thecaisson opening.
Life-string is connected with the supporting frame. If there is any accident,
worker can switch on the alarm and hold the life-string. Thus, people on
ground level cab know it and pull out life-string to rescue immediately.
The piezometer point and settlement point are useful for checking against
the effect of excavation on the underground water level and ground settlement.
It is very important to the safety of adjacent structures.
