3.1.1 Testing and Evaluation
One 6 metre long sample wire was removed from each groove and was tested in a local laboratory . The majority of the testing was tensile , with each sample providing ten tensile specimens . A total number of tensile tests was 704 .
A few wires exceeded the upper specified strength limit . A large proportion ( 31 %) of the test samples lies below the minimum specified tensile strength ( 100 Imp ).
One specimen from each sample wire was measured up for the stress-strain relationship . Zinc coating tests were carried out .
The cable strength was evaluated with focus on the proportion of the wires that have cracks . Of the 46 Stage 4 wires tested , 11 found to have cracks . They all lay within the outer 6 rings of wires . It was recommended that the current strength loss was between 8 and 10 %.
Loads in the main cables were reviewed . It showed that the bridge was somewhat lighter at opening than expected , but subsequent additions and modifications added up the weight near the original intention . The dead load is about 158 kN / m in the main span and 210 kN / m in the side spans . Live load was also assessed . However , the cable force is dominated by the dead load .
3.1.2 Cable Safety
Given the limited nature of a first inspection and the inherent lack of certainty in the results , it was agreed to set the minimum acceptable factor of safety as 2.0 .
After confirmation that the cables were safe , further investigation focused on future predictions .
The predicted changes in cable loading and strength with the corresponding factor of safety are given below :
Figure2 : Predicted changes in cable loading and strenths , with the corresponding factor of safety
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