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Concrete In Australia : March 2013
Concrete in Australia Vol 39 No 1 23 prepared horizontally and tested on the following day in a vertical position. In these situations, the concrete strength in its very early age represents a critical factor and governs the performance of the anchorage system. ree different types of anchors, shown in Figure 1, were tested in the experiments. ese are denoted as CA05240, SJH and EPA09. For each insert, four panel samples were prepared: two panels with no reinforcement placed in the vicinity of the anchor (this reinforcement arrangement is referred to as REO1 in Figure 2) and two panels with reinforcement covering the entire specimen (referred to as reinforcement arrangement REO2 in Figure 2). In total, 12 precast concrete samples were prepared to test the behaviour of the lifting anchors under tension. 2.2 Test specimens All concrete specimens were 2000 mm long, 800 mm wide and 150 mm thick. Each panel had one anchor placed at the centre of the panel long edge and its installation was carried out following standard industry practice. e extensive length of the longitudinal long edge was specified to minimise the possible influence from edge effects of the panels on the measured response of the lifting anchors. e details of the panels are illustrated in Figure 2. e two different reinforcement arrangements, ie REO1 and REO2, are shown in Figure 2. In the case of REO1, no reinforcement was present over the top 500 mm of the sample. For anchor types EPA09 and SJH, the upper longitudinal bar of the mesh was located as high as possible into the anchor specimens in between the hairpin legs. is detailing was specified to evaluate the influence of the reinforcement on the response of the anchor. Two small anchors were placed at the top side edges of the panel and were used for the lifting of the panel from the horizontal casting position to the vertical one adopted for the test. Four embedded inserts, located on the long edge opposite the edge containing the lifting anchor, were used to hold the panel down to the laboratory strong floor (as shown in Figure 3). e summary of the anchor and reinforcement details used in the tests is presented in Table 1. 2.3 Test setup Specimens prepared with reinforcement arrangement REO1 were cast at the same time with the same batch of concrete. e next day the specimens were loaded to failure. Similar to the first set of samples, specimens with reinforcement arrangement REO2 were cast at the same time with the same batch of concrete and tested to failure on the following day. e panels were lifted into vertical position and were anchored to the laboratory strong floor prior to testing using threaded bars screwed to the embedded inserts in the panel (Figures 3-4). Each lifting anchor was hooked to the appropriate lifting clutch. e lifting clutch was attached to Figure 1. Different types of anchors used in the experiments. CA05240 SJH (Swift Lift JAWSTM Heavy) EPA09 (EdjproTM) Reinforcement arrangement REO1 SL82 mesh N12 bars Reinforcement arrangement REO2 A A SectionA--AofEPA3&EPA4 SL82 mesh SectionA--AofCA4 500 mm SectionA--AofSJH3&SJH4 SL82 mesh SL82 mesh SL82 mesh SectionA--AofCA3 200 2000 800 CL 300 150 Hole for the threaded bar Embedded inserts for anchoring the panel to the laboratory strong floor during the experiment Inserts for lifting the panel from horizontal to vertical position Lifting anchor 250 Figure 2. Details of the layout and reinforcement arrangement used in the panels. Figure 3. Arrangement of the lifting anchors inserted in the panels.