1 00:00:05,640 --> 00:00:07,920 Today, damage to the monument that is a cause of concern 2 00:00:07,920 --> 00:00:10,850 is the splintering of the limestone used 3 00:00:10,850 --> 00:00:14,790 which is resulting in a progressive decrease in the amount of matter in the outer pillars. 4 00:00:15,200 --> 00:00:19,160 We may ask ourselves to what extent it is necessary to replace some of the damaged blocks. 5 00:00:20,940 --> 00:00:25,040 People with various skills were brought together to come up with the best solutions. 6 00:00:25,050 --> 00:00:28,650 Archeologists, architects, engineers, scientists, stone cutters, 7 00:00:28,650 --> 00:00:32,850 and surveyors were invited to participate in the reflections, so that their mastery of today's tools 8 00:00:32,850 --> 00:00:35,350 could serve to save the amphitheater. 9 00:00:38,000 --> 00:00:40,120 For instance, the very latest 3D laser 10 00:00:40,120 --> 00:00:44,160 scanner digital technologies were used to establish a precise 11 00:00:44,160 --> 00:00:46,660 record of the current state of the structure. 12 00:00:48,160 --> 00:00:50,420 The comparison of the ideal digital model, 13 00:00:50,420 --> 00:00:53,020 created in respect of the rules of the art of the Roman builders, 14 00:00:53,020 --> 00:00:54,820 revealed the amount of damage there is. 15 00:00:57,160 --> 00:00:59,300 The degradation occurring at the surface of the stone 16 00:00:59,300 --> 00:01:02,080 is probably due to the combined action of several factors. 17 00:01:04,720 --> 00:01:06,700 The first factor is linked to the technique 18 00:01:06,700 --> 00:01:09,880 of installing large blocks on top of each other 19 00:01:09,880 --> 00:01:11,240 with no mortar. 20 00:01:13,020 --> 00:01:15,960 Other factors may be linked to the progressive deterioration of the building. 21 00:01:16,460 --> 00:01:18,840 For example, the remarkable rainwater drainage system, 22 00:01:18,840 --> 00:01:21,300 built by the Romans, no longer functions as in the past. 23 00:01:24,460 --> 00:01:27,800 As a result, water tends to seep into the structure where is stagnates. 24 00:01:27,810 --> 00:01:31,970 When Barutel limestone, which is found in the pillars of the facade, absorbs water 25 00:01:31,970 --> 00:01:35,250 it expands and loses a significant amount of its mechanical resistance. 26 00:01:37,840 --> 00:01:40,700 Before arriving at the level of the base blocks, we must first quantify the forces 27 00:01:40,719 --> 00:01:44,009 that transit through the structure by calculating the load capacity. 28 00:01:44,500 --> 00:01:49,320 We focused on 5 of the 60 sections, which already represents a model of 5,000 blocks. 29 00:01:49,860 --> 00:01:52,120 The discreet element method we used, 30 00:01:52,120 --> 00:01:55,540 computes the movement of each block while taking account of the external loads 31 00:01:55,540 --> 00:01:58,760 and the contact forces exerted with the neighboring blocks. 32 00:01:59,020 --> 00:02:00,940 By calculating the load capacity, 33 00:02:00,940 --> 00:02:03,840 the forces exerted on each block can be evaluated more precisely. 34 00:02:03,840 --> 00:02:06,869 We can then focus on the most severely damaged blocks 35 00:02:06,869 --> 00:02:09,229 and study more precisely what exactly occurred in the material. 36 00:02:09,229 --> 00:02:11,769 By using a finite element method 37 00:02:11,769 --> 00:02:14,940 we were able to study the roles of the various factors already mentioned. 38 00:02:14,950 --> 00:02:18,580 Here, we are viewing the impact of an irregular contact surface 39 00:02:18,580 --> 00:02:20,980 qdue to the imprecision in cutting the stone. 40 00:02:20,980 --> 00:02:25,050 Now we are taking account of the expansion of the stone when water is present 41 00:02:25,050 --> 00:02:27,760 and seeps into its two very exposed faces. 42 00:02:27,760 --> 00:02:32,220 The blue tone expresses tension in the humid outer layers, 43 00:02:32,220 --> 00:02:37,900 which exceeds the limit the material can support. In reality, this situation would lead to the appearance of cracks. 44 00:02:37,900 --> 00:02:41,760 These cracks get bigger, which causes the splintering of the stone we have observed. 45 00:02:42,500 --> 00:02:46,620 These factors of degradation were probably already known by the Roman builders, 46 00:02:46,620 --> 00:02:51,060 because many elements in the design of the monument seem to have been imagined to avoid them. 47 00:02:51,460 --> 00:02:53,460 However, their effects on the durability of the Arena, 48 00:02:53,460 --> 00:02:56,040 after 2000 years of history, can be better understood 49 00:02:56,040 --> 00:03:01,519 thanks to this multidisciplinary project. The tools developed provide decision making aid, 50 00:03:01,519 --> 00:03:04,760 which offers constructive input in the thorny debate about 51 00:03:04,760 --> 00:03:06,630 the restoration of a historic monument.