# Macro-Modelling Approach for the In-Plane Cyclic Response of Cold-Formed Steel Partition Walls
## 4 Validation of the Proposed Analytical Model  
### Overview of CFS Partition Wall Experiments and Their Analytical Models  
In order to validate the suggested analytical model of CFS partition walls, two full scale specimens were prepared and tested for this study, as shown in Figure 9a. CFS partition wall specimens erected according to the Korean construction practices consist of single bay with 1.8 m of length and 2.1 m of height without return walls at each end. Symbols of ST600 and ST450 shown in Figure 9b were named according to stud spacings of 450 mm and 600 mm of the specimens considered as a main experimental parameter for quasi-static tests. GBs and studs of the specimens were screwed to the top and bottom tracks. To evaluate the drift sensitive partition wall, a quasi-static test loading protocol [32] was used with a total of 15 steps. The loading protocol consisted of repeated cycles of stepwise increasing deformation amplitudes. The first displacement level corresponding to 0.15% drift ratio was determined as the specimens remain in the elastic range. Other displacement levels consisted of an increase up to 1.4 times the amplitude of previous step. Two cycles were repeated for each amplitude. The maximum displacement level was considered to be 5% of lateral drift. Figure 10 presents the loading protocol in terms of drift ratios. In order to identify the physically observed damage, visual inspection was carried out after each loading step.  
Figure 8: The hysteresis of the Wayne–[PERSON] model (from [PERSON] [31]).  
Figure 10: Loading protocol for the quasi-static loading test.  
Figure 9: Test specimens: (**a**) Test setting; (**b**) Distribution of studs and gypsum boards of ST600 and ST400 specimens.  
The analytical models for the specimens were constructed using RUAUMOKO 2D [32]. The material properties of studs were determined from coupon test results [33] and the elastic modulus and yield strength were 208 GPa and 395 MPa, respectively. The structural properties of screw connections erected were determined from test results performed by [PERSON] and [PERSON] [27], of which the specimens had been constructed with two layers of GBs attached to CFS studs with 300 mm spacing of screws, as presented in Figure 11.  
Figure 11: Material test results of the screw connection (after [PERSON] and [PERSON] [27]): (**a**) test specimen; (**b**) test result.  
According to the procedure mentioned earlier, the backbone curves of the screw connections, GBs, and studs employed into the specimens were established, as shown in Figure 12. The ST600 and ST450 specimens consist of two GB panels (denoted as GB1 and GB2 in the figure) and three GB panels (denoted as GB3, GB4 and GB5 in the figure), respectively. Each GB panel is comprised of three spring assemblies. For example, the GB1 panel consists of e1, e2 and e3 spring assemblies which represent the screw connections, GBs and studs. Of these spring assemblies, e2 and e3 spring assemblies include the primary spring and contact spring, as mentioned earlier. All three spring assemblies are parallelly-connected in the horizontal direction. For the screw connections, the monotonic behavior of an e1 spring element is obtained from combining the monotonic behaviors of several screw connections comprised of a partition wall. The idealized trilinear curves are then implemented for the e1 spring elements. Gaps are included into the monotonic behaviors of e2 and e3 springs due to the presence of contact elements.  
Figure 12: Determination of monotonic behavior of elements consisting of specimens: (**a**) distribution of elements; (**b**) backbone curves.