## 5 Results
The average values of normalized ultimate capacity, as well as standard deviations, are also provided in Table 4. It was observed that in terms of thickness effect, as the cross-section area of this type of upright is smaller than the area of 2.5 mm thick upright, the ultimate load is significantly reduced. Figure 13: Failure modes of upright frames with 2.5 mm thickness. Figure 14: Load displacement curves for 1.6 mm thick specimens. \begin{table}
\begin{tabular}{l c c c} \hline \hline  & & **Normalized Buckling Load (\(\frac{f}{\delta_{\varphi}\times A_{\mathbf{z}}}\))** \\ \cline{2-3}
**Test Specim** & **Without Bolt** & **Reinforcement at 400 mm** & **Reinforcement at 200 mm** \\ \hline
1200L-1.6T-Test 1 & 0.471698 & 0.54236 & 0.646223 \\
1200L-1.6T-Test 2 & 0.483321 & 0.50473 & 0.665111 \\
1200L-1.6T-Test 3 & 0.476235 & 0.52041 & 0.650512 \\ Ave. & 0.476231 & 0.52247 & 0.653952 \\ Std. & 0.005916 & 0.01870 & 0.009901 \\ \hline
1800L-1.6T-Test 1 & 0.451874 & 0.503868 & 0.576726 \\
1800L-1.6T-Test 2 & 0.444332 & 0.503357 & 0.610181 \\
1800L-1.6T-Test 3 & 0.440257 & 0.485003 & 0.593035 \\ Ave. & 0.446066 & 0.497177 & 0.590108 \\ Std. & 0.005901 & 0.010733 & 0.017146 \\ \hline
2400L-1.6T-Test 1 & 0.440072 & 0.454801 & 0.525893 \\
2400L-1.6T-Test 2 & 0.450944 & 0.475199 & 0.504333 \\
2400L-1.6T-Test 3 & 0.451272 & 0.482727 & 0.484913 \\ Ave. & 0.446066 & 0.469298 & 0.501824 \\ Std. & 0.006552 & 0.014544 & 0.020863 \\ \hline
3000L-1.6T-Test 1 & 0.472318 & 0.492159 & 0.513533 \\
3000L-1.6T-Test 2 & 0.469112 & 0.46586 & 0.533885 \\
3000L-1.6T-Test 3 & 0.455033 & 0.468322 & 0.485468 \\ Ave. & 0.464652 & 0.473945 & 0.50647 \\ Std. & 0.0092 & 0.014637 & 0.024905 \\ \hline
3600L-1.6T-Test 1 & 0.308389 & 0.303046 & 0.346258 \\
3600L-1.6T-Test 2 & 0.320749 & 0.328183 & 0.339846 \\
3600L-1.6T-Test 3 & 0.33046 & 0.342123 & 0.349139 \\ Ave. & 0.32061 & 0.325256 & 0.343842 \\ Std. & 0.011059 & 0.019794 & 0.004972 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The average normalized ultimate capacity of uprights with 1.6 mm thickness. Figure 15: _Cont._As shown in Figures 14 and 15, the load-displacement trends and failure mode patterns for uprights with 1.6 mm thickness are somewhat similar to those observed in the tests for uprights with 2.5 mm thickness. Nevertheless, the normalized ultimate capacity for 2.5 thick upright is higher compared with the corresponding values of lower thickness uprights. For the 1.6 mm thick specimens, distortional buckling was the primary buckling failure for specimens with 1200 mm and 1800 mm length, while for the specimen with 2400 mm the failure was followed by flexural buckling or flexural-torsional buckling mode. For specimens with 3000 mm and 3600 mm length, the primary failure was flexural-torsional buckling of upright about the weak axis. Similar to uprights with 2.5 mm thickness, the failure mode observation reveals that the reinforcement has a slight influence on the ultimate load-bearing capacity of uprights with 3000 mm  
Figure 15: Failure modes of upright frames with 1.6 mm thickness. and 3600 mm and the best application of reinforcement method is for lower lengths of 1200 mm and 1800 mm due to the improvements in local and distortional buckling modes.