Statically Indeterminate Plate Test

In addition to the statically determinate beam tests, the long term behaviour of SFRC and PFRC plates on continuous support has been investigated (Table 4). The focus of this investigation is directed to the analysis of the long term behaviour of tunnel linings under rock pressure around an anchor bolt. For this purpose, a long term test setup is built so as to load cast panels according to EN14488-5 [3]. Per tested series, 3 FRC square plates of 600 mm x 600 mm x 100 mm are centrally loaded in a displacement controlled manner as shown in Fig. 2. The pre-cracking test is ended at a specified 5_pc (Table 4) of the centre point of the panel. The maximum load and thus the relevant crack pattern are usually achieved at deflections from 2 to 3 mm. But while in some cases 2 mm deflection is sufficient to

Table 4 Overview of centrally loaded plate tests

Fig. 2 Setup of EN14488-5 creep test method reach this level, a deflection of 3 mm is preferred. Otherwise the specimen could still be in the phase of initial cracking, not having developed the final crack pattern.

The load-deflection curve is recorded and F_r is registered. The deflection recovery was not measured. The plate is then moved to the permanent setup of a rigid steel square loading block having a contact outline of (100 ± 1) mm x (100 ± 1) mm and where F_creep is applied, equivalent to 40-60 % of F_r. F_creep in program B2 was adjusted over time up to 80 % F_r as shown in Fig. 7. The deflection is measured at regular intervals. 5_creepm (Table 6) is, similarly to the beam tests, the average of the individually registered deflections due to creep at failure or last measured point. The fibres which are taken up in programs B2 and B3 are fibres commonly used in shotcrete applications. Specimens with 25 kg/m³ 3D 65/35BG and 7 kg/m³ PF-73/65, were loaded with similar F_creep as shown in Table 7.

Table 5 Overview of statically determinate beam tests

Fig. 3 Program A1: 4-point bending on 150 mm x 50 mm x 500 mm at 50 % F_r (S_pc = 5 mm)

Fig. 4 Program A2: 3-point bending on 1500 mm x 870 mm x 40 mm at 60 % F_r (S_pc = 3 mm)

Fig. 5 Program A: 3-point bending test (based on EN14651) at 60 % F_r (CMOD_pc = 0.5 mm)

Table 6 Overview of statically indeterminate plate tests

Fig. 6 Program B1: EN14488-5 on 600 mm x 600 mm x 100 mm at 60 % F_r (S_pc = 3 mm)