3.1.2. Five Design Assumptions

3.1.5 Design Assumptions
Part
No design assumptions were needed in the modelling of the bolt, only that the base plate and bolt are connected with no weld area. The concrete structure was initially made with a width, breadth and height of 1m. The area where the bolt would be placed was cut out using the cut extrusion function in ABAQUS. Due to the large design of the concrete block, it is difficult to define a workable size mesh for the problem, as can be seen in Figure 24 and 25. Figure 24:Assembled concrete block and bolt showing concrete area compared to the bolt area

Figure 25:Assembled concrete block and bolt with mesh

During the pull-out of the holding-down bolt, the area under the bolt is not affected by the bolt, due to another
In test one, the concrete strength for both, the ABAQUS model, Experimental model and design failure were at 26 MPa. There was no need to make any adjustments to the existing data in order to get realistic comparisons with data. Both concrete models consisted of a concrete strength of 26 MPa (ABAQUS and experimental data). The data shows that the design failure (As predicted by The Green Book) is designed very conservative, because the ABAQUS failure was 23.38 kN and the design failure 21.7 kN. When the experimental data is compared with the ABAQUS data, it can be seen that the failure rate off all the different samples tested are much higher than the ABAQUS analysis. The Experimental data averages a difference of 9.72 kN higher than the data collected in ABABAQUS. Failure force in the test samples varied from 26.2 kN to 40.1 kN. More sample tests would have been preferred in order to get a more accurate experimental prediction to compare with this study data. By comparing the design force with the ABAQUS force, it can be seen that the ABAQUS data fails at a 7.74% higher force than predicted by the design failure force. By comparing the Experimental data with the ABAQUS data, it can be seen that the ABAQUS data fails at a 29.37% lower force than predicted by the experimental failure
This is due to the fact that the concrete model used in ABAQUS has a concrete strength 26 MPa and the concrete strength for the experimental and design failure data is 22 MPa. By analysing the experimental data, the concrete strengths used in the tests varied from 22 MPa to 31 MPa. With this data it will be easy to get an adjustment factor that can be used for a more accurate prediction of the correct failure in the ABAQUS data. For the purpose of this study it is assumed that extrapolation can be used to get the correct failure strength for the ABAQUS failure data. Also, in the first test is could be seen that the failure force of ABAQUS was 29.37% lower than the average experimental force. With all this in consideration, it will be assumed that the ABAQUS failure force can be adjusted by a factor of 0.896. The adjusted failure force for ABAQUS in test two is 36.88 kN for a concrete strength of 22 MPa. By comparing the design failure data with the ABAQUS failure data, it can be seen that the ABAQUS failure data fails at a 25.44% higher force than the predicted failure force. By comparing the experimental failure data with the ABAQUS failure data, it can be seen that the ABAQUS failure data fails at a 41.09% lower force than the experimental failure