## 3 Results and Discussions  
### Application of 1D Norton-Bailey Time-Hardening Power Law  
The parameters of the Norton-Bailey power law (time-hardening) in Equation (1) were obtained using an approach similar to the one presented by [PERSON] and [PERSON] [30]. Three locations were selected from the creep strain versus time relationship, and their corresponding strain values were selected at the given stress values, as shown in lines a, b, and c in Figure 3. Thus, the parameters were computed based on Equations (2) and (3). This approach assumes that the model parameters are stress independent [50,51]. By substituting the computed parameters m and n in Equation (1), the value of A was determined. \[\log\frac{\varepsilon_{\sigma 2,b}}{\varepsilon_{\sigma 1,a}}\ =\ \left(\log\frac{ \mathrm{t}\sigma_{2,b}}{\mathrm{t}_{\sigma 1,a}}\right)\mathrm{m}+\left(\log \frac{\sigma_{2}}{\sigma_{1}}\right)\mathrm{n} \tag{2}\]  
Figure 3: Typical experimental flexural creep strain of WPC specimens subjected to three levels of stress (7% Fb, 14% Fb, and 29% Fb) and the corresponding Norton-Bailey power low model prediction. \[\log\frac{\epsilon\sigma_{3,c}}{\epsilon_{\sigma 2,b}}\ =\ \left(\log\frac{t_{\sigma 3,c}}{t_{ \sigma 2,b}}\right)m+\left(\log\frac{\sigma_{3}}{\sigma_{2}}\right)n \tag{3}\]  
Table 1 represents: a summary to the experimental results obtained from the quasi-static testing, the applied levels of stress (flexural) to each group of WPC and the stress level applied to each WPC specimen in each group, the values of inserted in Equations (2) and (3), and the computed parameters. Figure 3 shows a typical relationship between the experimental creep strain versus time of three WPC specimens at three different stress levels (7% Fb, 14% Fb, and 29% Fb) and the selected lines (a, b, and c) on these relationships used to compute the Norton-Bailey parameters [19; 20]. The mechanical properties were: Fb = 41.2 MPa and E = 4.34 GPa. The applied stress levels were: \(2.98\pm 0.08\), \(5.88\pm 0.04\), and \(11.84\pm 0.1\) MPa. Modeling the Long-Term Deformation of an Aquacultural Geodesic Spherical Rigid Frame Structure Made from WPC Lumber  
WPCs showed a potential to be used in the construction of the rigid frame structure of the Aquapod in addition to its relatively high elastic modulus compared with HDPE lumber (approximately five times higher) [13; 14]. However, the WPCs time-dependent behavior is a subject of concern during the service life of the structure. Figure 4A,B shows the FEA time-dependent model of the aquacultural geodesic spherical rigid frame structure for 10 years and subjected to the weight of the structure distributed among the hubs (the points that connects the WPC struts). The maximum creep strain (in-plane strain at the hanging points shown in Figure 4A) was 0.002 which is 20% of the strain at failure established for this 3D model. In the design of conventional structures (steel or reinforced concrete) different methods are used to compute the factor of safety of the structure. Allowable stress design (ASD) method for instance, it is based on the design strength of the material at the lower 5 th percentile during the service life (10 years) [3]. The factor of safety which is the ratio between the design strength to the applied stresses (working stresses) for structures is selected based on the environmental conditions, the design factors, and the types of loads applied to the structure. In this method (ASD), it is assumed that the structure is linearly elastic and the deformation is computed accordingly. However, to consider the viscoelastic materials in structural application, the time-dependent deformation has to be computed during the service life of the structure (for instance 10 years) to be included in the total deformation of the structure.