## 3 Results and Discussion
### Fragility and CMR Analysis  
The seismic performances of the transmission steel tower under Far-Field (FF), Near-Field (NF) and Repeated ground motion records were determined using fragility curves by recording the damage for three performance limit states (IO, LS, and CP) in terms of possibilities of damages at two different intensities of spectral acceleration Sa(T1, g), which  
Figure 13: Deformation and failure mode for three seismic scenarios at life safety/repairable stage; (**a**): Far-Field, (**b**): Near-Field, and (**c**): Repetitive earthquakes. were chosen at 1.0 g and exceeding 1.0 g for observing the dynamic behavior of the selected tower as shown in Figure 14.  
Figure 14: Fragility curves for three seismic scenarios based on the relation between Sa(T1, g) and P[Damage]; (**a**): Far-Field, (**b**): Near-Field, and (**c**): Repetitive earthquakes. At intensity measure 1.0 g, t the three performance levels, IO, LS and CP, for the three seismic scenarios intersect at the Sa(T1, g) = 1.0 g, having the same possibility of damage which roughly equals 30%. Nevertheless, before reaching the inflection point of 1.0 g, the probabilities of damage in the case of far-field seismic scenarios for the three performance levels are substantially greater than the near-field and repeated seismic scenarios. However, beyond 1.0 g as the inflection point in this study, the probabilities of damage for the three performance levels at the far-field ground motion become significantly lower than the near-field and repetitive ground motions. For example, at intensity measure 2.0 g, the possibilities of damage for reaching or exceeding the IO state are 70%, 90%, and 100% for far-field, near-field, and repeated ground motions, respectively. However, at the same intensity measure, the structure showed the possibility of damages during far-field 45%, and 40, for LS and CP states, respectively. The possibility of damage becomes more significant when near-field ground motion has impacted the tower by reaching (60%, and 50%), and during repetitive events 80%, and 70% for LS and CP states, respectively. The occupancies of structures are considered to be critical and must be monitored during earthquake events. When considering near-field ground motions and multiple scenarios, it can be seen that the structures rapidly lose their occupancies as the intensity measures increase; in the case of near-field, the structure possibility of damage to be complete in-occupant of 100% occurring at 2.50 g, which vanishes earlier compared to the far-field events that achieved this stage at 5.0 g, and earlier at 2.0 g during repetitive ground motions, which is clearly showing in the radar graph between Sa and probability of damage as shown in Figure 14.  
Furthermore, a structure's life safety is threatened during seismic events, and it is considered an important stage after the structure occupancy stage that could help in estimating the need for repair. In this study, the three seismic scenarios have different life safety states. However, considering the 50% possibility of damage as half-life threatening structures is the key for monitoring the tower structural behaviour. Starting with the far-field seismic events, the structure can be retrofitted if the intensity measure does not exceed the 2.50 g spectral acceleration. On the other hand, during near-field seismic events, the structures can be repaired if the intensity measure equals 1.50 or less, and 1.20 g in case of multiple seismic scenarios. According to the collapse margin ratio (CMR) initially proposed by FEMA P695, the intensity measure (I\({}_{50\%}\)) for reaching 50% of the structural collapse for the far-field, near-field and repeated earthquakes are 3.50 g, 2.0 g, and 1.40 g, respectively. From these values and the Maximum Considered Earthquake (MCE) value of 0.30 related to the Lebanese seismic hazard map, the CMR is established.