## 3 Characteristics of Ice Accretion on Diverse Members
### Ice Accretion on Section Steel  
The ice shapes of the medium-size section steels at various \(\gamma\) are shown in Figure 18, and the side views of ice accretion for L100 and \(\gamma=90^{\circ}\) at different \(N\) are shown in Figure 19. The mean ice sizes of the section steel at \(N=80\) are listed in Table 2.  
Figure 19: Side views of ice accretions for L100 and \(\gamma=90^{\circ}\). The key observations are summarized as follows:  
1. [label=(0)]
2. Figure 18 shows that two rows of icicles formed on the two sides for each section steel, and ice was produced on the surfaces facing the droplets. The icicle length and spacing had significant non-uniformity. The size effects of \(B_{t}\), \(B_{b}\), and \(B_{s}\) were non-significant, as shown in Table 2.
3. For the angle steel, the ice thickness on the top wall (\(\gamma=90^{\circ}\)) was smaller than that on the bottom wall (\(\gamma=0^{\circ}\)). This was due to some of the droplets being prevented from flowing down by the lateral wall for \(\gamma=0^{\circ}\), and consequently, \(B_{b}>B_{t}\). \(l_{s}\) for \(\gamma=0^{\circ}\) was much larger than that for \(\gamma=90^{\circ}\). For the U-steel and I beams with \(\gamma=0^{\circ}\), most of the icicles were connected to the bottom wall, and therefore, the \(l_{t}\) values in Table 2 were inaccurate. 4. As shown in Figures 18 and 19, the icicles on all components could be simplified as circular truncated cones with \(s=2\)-\(52\) mm. The \(d_{b}\) of the icicle was about \(5\) mm, while \(d_{t}\) increased with increasing \(N\), and the adjacent icicles would connect after \(d_{t}>s\), therefore the individual icicles begin to merge into an icicle curtain. At the early stage, ice on the lateral wall was in the form of flat icicles, and only some local areas accreted ice. The whole range was almost uniformly covered by ice when \(N\) was large enough. The major observations are summarized as follows:  
1. The ice thicknesses and ice shapes on the pipelines of the section models were roughly the same as those on the circular cylinders described in Section 3.1. Only one row of icicles was formed under each guardrail of girders A and B due to its small diameter (\(D\) = 10 mm), which agreed with the results for ice accretion on transmission lines [37]. 2. The ice shape of the truss stiffening girder was related to the \(\gamma\) of its components. A large amount of ice accumulated on the upper surface for the horizontal and inclined bars, while only a slight amount of ice with a rough surface grew on the surfaces of the vertical bars, and the other surface of the truss stiffening girder had little ice. The areas and thicknesses of the components facing the droplets were increased by the ice on the truss stiffening girder. These results agreed with those in Section 3.3. Therefore, the above results for pipelines and section steels could be used as references for simulating the ice accretion on pipeline girders. 3. Since the grate plate was composed of interconnected slender elements, the ice accretion on adjacent elements connected, which resulted in a decreased porosity and an increased thickness, respectively (Figure 21). Meanwhile, a large number of icicles were produced under the grate plate, which was like a large icicle matrix. However, the sizes of the icicles under the grate plate had upper limit, and they would stop growing after the porosity of the grate plate became zero. 4. For girder C, due to the obstruction of the upper pipeline and truss, the \(\delta_{0}\) of the upper layer (5 mm) was much larger than that of the lower layer (2 mm), and the \(l_{\text{mean}}\) of the upper pipeline (85 mm) was larger than that of the lower pipeline (59 mm). \(B_{t}\) of the middle horizontal trusses (13.6 mm) was larger than that of the top ones (10.5 mm), while the average \(B_{t}\) of the bottom section steel was the smallest one (7.7 mm).