ASTM A1034, ICC AC133, Hong Kong Building Department COP Clause 126.96.36.199 and ISO 15835 all have similar requirement for low cycle tension-compression fatigue for mechanical reinforcing bar splices. Industry norms which are typically utilized to calibrate the performance of mechanical splices are ASTM A1034, ICC AC 133, HKBD COP Clause 188.8.131.52 and ISO 15835.
The purpose of this test is to evaluate the performance of the splice reinforcement following significant inelastic stress reversal fatigue cycles which would simulate a seismic event. This includes a series of elastic stress reversal cycles followed by increasing inelastic stress reversal cycles out to 5 times the yield point strain of the reinforcement being tested.
During this cyclic excursion, movement across the splice is carefully monitored to determine if there is any excessive permanent motion, or slip, which could cause excessive cracking which could degrade the structure. RHINO technical experts helped to develop these rigorous tests that assure the mechanical splicing system will not be the weak link in the structural system.
Following this completion of the cycles the test specimen is then pulled to its ultimate strength. RHINO Mechanical Connections successfully pass this rigorous test, while developing the full strength and ductility of the reinforcement. The stages of this test are noted in Table 1.
Table 1 - low cycle fatigue test cycles.
Extensometers measure the strain in both the reinforcement and the coupler, sophisticated software records the strain and precisely controls the test regiment during the compression and tension cycles. Mechanical splices that meet the requirements of these norms are suitable for use when inelastic yielding may be expected. According to ACI 318, Type 2 mechanical splice is the only mechanical splice type permitted to be used anywhere in a structure.