_REVISION - M1981302 ‎(94)‎

• Permit No: M1981302
• IBM Index Class Name: Revision
• Doc Name: VISUAL INSPECTION
• Type & Sequence: TR6
• Media Type: D
• Archive: No

• • 25
COVERAGE 4.7 RECORD KEEPING
The inspection is conducted by walking along and A dated report should be filled out for each periodic
over the dam as many times as is required to see every inspection.This report should be filed along with any
square foot. From any given spot a person can usually pictures that were taken.The pictures should be dated
gain a detailed view for a distance of 10 to 30 feet in to keep them identified with the correct inspection
each direction, depending on the smoothness of the date. Inspection observations can be recorded on the
surface or the type of material on that surface, i.e.• report format at the end of this chapter.
grass, concrete, riprap, brush. Two items are especially important to note during the
An inspector can view from 10 ft. to 30 ft.,depending inspection to allow the observations to be evaluated
on cover. properly.
THE INSPECTOR MUST BE CAREFUL TO
�k it ��� ���\ RECORD:
1. GAGE ROD READING
1 2. WEATHER CONDITIONS THAT INFLU-
FIGURE4.5.1 SIGHT DISTANCE ENCE OBSERVATIONS ESPECIALLY RE-
To cover expansive surfaces properly, several walk- CENT RAINS, EXTENDED DRY SPELLS,
ings are required. SNOW COVER, ETC.
In addition to the inspection observations any moni-
toring measurements should be recorded in a useful
format and made a part of the inspection record.
} 4.8 EVALUATION OF INSPECTION
OBSERVATIONS
The record of periodic inspection observations is used
to develop a mental picture of the dam's performance.
FIGURE 4.52 SUCCESSIVE PASSES The accurate measurements pay off here because
Adequate coverage can be achieved using a parallel or small changes, which would go undetected if simply
zigzag path. looked at,will show a pattern or trend and the owner
can begin addressing any potential problem before it
becomes a threat to the dam.
Immediately following the inspection the observa-
tions should be compared with previous records to see
if there is any condition, reading, or trend that may
indicate a developing problem. When a significant
i change is seen,design drawings for the dam should be
examined carefully to see if an obvious reason for the
DOWNSTREAM SLOPE DOWNSTREAM SLOPE change can be found. If a questionable change or
trend is noted, the inspector should not hide it. He
FIGURE 4.53 COVERAGE PATH should contact oneoftheprofessional engineers in the
On the downstream slope a zigzag path is recom- Inspection Unit of the State Engineer's Dam Safety
mended to assure that any cracking is detected. Branch or his own consulting engineer. The engineer
STOP AND LOOK—At several points on the slope, will determine if any action, such as increased moni-
the inspector should stop and look around for 360'to toring or detailed investigation of the condition, is
check alignments and to be sure he has not over- required.
looked some important feature of the slope. This cooperative action will help assure the safety;
jSEQUENCE safe operation; and long, useful life of the dam.
s A productive sequence of inspection that has been 4.9 SUGGESTED PLANNING
used with favorable results is: Getting the most out of an inspection requires some
UPSTREAM SLOPE preparatory work:
CREST I. The previous inspection report should be reviewed
to note any areas which will require special
DOWNSTREAM SLOPE attention.
ANY SEEPAGE AREAS 2. If the purpose of the inspection is to re-evaluate
OUTLET questionable conditions discovered during the
SPILLWAY last inspection, available design or construction
drawings should be examined to see if they might
Following a specific sequence will lessen thechanceof explain the situation.
an important condition being overlooked. Reporting .
Inspection results in the same sequence is recom-
mended to allow consistent records. i
it