## 4 Comparison of Design Specification Provisions
### Numerical Comparison of Provisions at the Positive and Negative Bending Moment Region  
The effective flange widths of continuous spans are calculated based on \"equivalent spans\" and \"basic provisions\", as discussed. In this section, the numerical values of the effective flange width are compared. Effective flange widths are calculated at the internal support regions of three-span continuous frames with the same exterior spans and solid concrete slab. The first calculation background and conditions are that the beam end span equals its mid-span, and the actual width of the concrete slab, \(2b\) of EN 1994-1-1 and AS/NZS 2327, \(S_{0}\) of GB50017, will change the ratio of \(S_{0}\) to beam span \(L\) (column distance) from 1 to 1/6. The second calculation background and conditions are that the beam end  
Figure 6: Equivalent span length ratios. span \(L1\) equals 1.5 times mid-span \(L\) (\(L2\) is in Figure 6), and it changes the ratio of \(S_{0}\) to \(L\) from 1 to 1/6. For example, the range of the regular column space or the beam span of SMRFs is about 7.5 m-12 m, and the scope of the usual supporting span of a solid concrete slab is about 1.8 m-6 m, so the ratio of 1-1/6 can cover them. Regarding \(b_{0}\), this is the distance between the centers of the shear connectors (Figure 4), and in this paper, we made \(b_{0}\) equal to the value of 0.01\(L\), where \(L\) is the beam mid-span. According to the regular column space or the beam span of SMRFs, \(L\) is about 7.5 m-12 m, and the value range of \(b_{0}\) is 75 mm-120 mm, which can cover the common distance of the shear connector in practical engineering structures. The value of \(b_{0}\) of EN 1994-1-1 is somehow different from that of GB50017, but the difference is slight. The resulting \(b_{\rm e}\) and \(L\) in the positive bending moment zone are listed in Table 2; the negative bending moment zone values are listed in Table 3. It can be seen in Table 2 that although the equivalent span length of the end support is greater than the mid-span when \(L1=L2=L3\), the effective width \(b_{\rm e}\) of the end support is less than the mid-span in Eurocode4 and AS/NZS 2327, and the reduction is between 8% and 18%. GB50017 is just the opposite, and improvement ranges from 0 to 32%; the two values are the same for AISC360. The reason for this is that EN 1994-1-1 and AS/NZS 2327 consider reducing the effective width at the end of the span and use a modification factor \(\beta\)i, Equation (3), which is applied to the one-side effective width at the end supports. However, GB50017 does not consider the reduction of the effective width at the end supports, and AISC 360 does not consider the difference in the slab's effective width at the end supports and mid-span. Moreover, the equivalent span length ratios of GB50017 are less than those of EN 1994-1-1 (shown in Figure 6). Still, both effective slab widths of GB50017 at the end supports and mid-span are larger than EN 1994-1-1 in Table 2, except \(S_{0}/L=1/6\). Among them, the maximum increase for the mid-span is 14%, and the top growth for the end support is 64%. The main reasons for the above differences are the effective width of the concrete flange on each side is taken as \(L_{\rm e}/8\) in EN 1994-1-1 and AS/NZS 2327, and is taken as \(L_{\rm e}/6\) in GB50017, where \(L_{\rm e}\) is the equivalent span according to Figures 4 and 6. When \(S_{0}/L\) takes a value between 1/6 and 1/3, both effective slab widths of AISC 360 at the end supports and mid-span is smaller than EN 1994-1-1 and GB50017. Compared with EC4, the maximum drop for the mid-span AISC360 is 53%, and the maximum reduction for the end support AISC360 is 42%. It can be seen in Table 3 that the variation rule of the effective width of the slab in the negative bending moment region considered is basically the same as the positive moment region in Table 2, and the reason is the same as well.