01 April 2001
Supporting Structures. Consideration of the supporting structure is a
critical component of planning a hardware test. Personnel responsible for carrying out
the testing program must determine the following:
The structural adequacy of the system to support the test load.
General condition of the supporting structure.
Once it is determined that the supporting structure was designed to handle the fitting
and the condition of the structure is sound, the test can be carried out.
Failure Modes. There are various modes of failure associated with
mooring hardware. In most cases of failure under in-service conditions occur in the
fasteners. When the fitting is embedded in concrete and does not utilize a bolted
connection the fitting will generally fail by cracking in areas of high tensile stress or
excessive bearing stress. It has been observed that some failures of mooring hardware
do not result from mooring line loads. These failures result from overload due to
vehicular impact, cranes accidentally setting loads upon the fitting, and other
miscellaneous incidents. This type of failure should be observed prior to conducting a
load test and should be grounds to abort the test. Mooring hardware with obvious
distress should be taken out of service immediately.
Failure under load test is generally associated with corrosion of the fasteners or failure
of the supporting structure. The following methods should be used for detection of
Visual observation of distress or movement.
Measured permanent yielding or displacement following release of
SECTION 5. METHODS
General. The purpose of a hardware test is to ensure that mooring
hardware is capable of holding its design load. Several general methods exist to test
Pull Testing. There are four methods of pull testing:
Pull test with a test rig, which may include jacking equipment.
Pull test with a land based crane or winch.
Pull test with a water based crane or winch.
Pull test similar mooring hardware one-against-the-other to test two
pieces of mooring hardware at once using hoisting equipment to
apply the load. Note: If fitting fails, take out of service immediately
and replace or repair as soon as possible.
Bolt Testing. Bolts transmit the load to the structure and are often the
critical component in many fittings. Therefore, consider testing the bolts in lieu of
testing the entire hardware. Bolts act in tension and shear to resist loads applied to
mooring hardware. Since most hardware is set in a grout or concrete base and have