1 00:00:00,160 --> 00:00:03,800 In the framework of the restoration of the amphitheater, what new approach are you considering? 1b 00:00:04,160 --> 00:00:08,579 Our work comes after some experimentations 2 00:00:08,579 --> 00:00:16,000 that enabled a scientific committee to raise some questions. 3 00:00:16,219 --> 00:00:19,150 As these questions were raised, 4 00:00:19,150 --> 00:00:21,400 studies were undertaken that opened some avenues of inquiry. 5 00:00:21,600 --> 00:00:23,800 However, none of them came up with a definitive response 6 00:00:23,800 --> 00:00:26,600 because the questions are fundamentally rather complex. 7 00:00:27,100 --> 00:00:32,400 I think everyone experienced the need to make a comprehensive study. 8 00:00:32,670 --> 00:00:35,500 Which is what we are doing today. 9 00:00:35,700 --> 00:00:38,500 And we're starting to see some elements emerge 10 00:00:38,500 --> 00:00:41,700 through which the studies that were conducted have been applied a particular situation. 11 00:00:41,900 --> 00:00:44,500 The diagnosis we made 12 00:00:44,500 --> 00:00:47,100 is one that concerns the entire amphitheater 13 00:00:47,100 --> 00:00:50,300 its outside facades, the interior of the cavea, 14 00:00:50,300 --> 00:00:55,800 the wide corridors for circulating, the staircases…All of that forms an ensemble. 15 00:00:56,300 --> 00:01:03,800 The conclusion of this diagnosis is that we cannot 16 00:01:03,800 --> 00:01:09,800 separate too distinctly the facade from the interior of the cavea. 17 00:01:09,800 --> 00:01:14,630 There's an outside block--a crown with the facade and 18 00:01:14,630 --> 00:01:18,800 the tiers that are below this crown, and an inside block. 19 00:01:18,800 --> 00:01:21,450 All of that houses the wide hallways for circulating within. 20 00:01:21,450 --> 00:01:25,580 This ensemble should be treated as a whole, 21 00:01:25,580 --> 00:01:27,800 part by part, given the scale of the monument, 22 00:01:27,800 --> 00:01:31,100 then, in a second phase, the remainder of the cavea. 22b 00:01:31,200 --> 00:01:35,160 What are the decisive factors in terms of the damage? 23 00:01:35,300 --> 00:01:40,800 The first observation we made immediately 24 00:01:40,800 --> 00:01:43,800 was of a very specific pathology: 25 00:01:43,800 --> 00:01:46,500 sorts of large flakes had formed 26 00:01:46,500 --> 00:01:48,500 and were continuing to form, 27 00:01:48,500 --> 00:01:51,250 including on the stone used for previous restoration. 28 00:01:51,250 --> 00:01:54,400 That's important because it's a process 29 00:01:54,400 --> 00:01:58,959 specific to this stone and in this configuration. 30 00:01:58,959 --> 00:02:01,500 We looked at what was happening on the amphitheater 31 00:02:01,500 --> 00:02:06,400 but also on other monuments built of Barutel stone. 32 00:02:06,420 --> 00:02:10,400 There's an ancient entrance in Nîmes that is built of Barutel stone 33 00:02:10,400 --> 00:02:15,800 and of which all that really remains is an arch, with not much of a load to support. 34 00:02:15,800 --> 00:02:19,000 So it's an arch with a light load. There's one facade that's nearly intact, 35 00:02:19,000 --> 00:02:24,000 and the other that has exactly the same kinds of degradation, the pathology 36 00:02:24,000 --> 00:02:27,100 we observe on much of the amphitheater. 37 00:02:27,100 --> 00:02:29,599 Which is linked to its exposition to rain. 38 00:02:29,599 --> 00:02:33,000 We made an overall list of all of the parts damaged 39 00:02:33,000 --> 00:02:37,000 and a map that sums up all of our observations. 40 00:02:39,800 --> 00:02:47,500 When we really observe on this map the location and the degree of this deterioration 41 00:02:47,500 --> 00:02:55,400 we realize that the most severely damaged parts are those that are the most exposed to wind and rain 42 00:02:55,489 --> 00:03:00,000 so there's an absolutely obvious correlation. 43 00:03:00,000 --> 00:03:02,029 So that's for the water that comes from the exterior. 44 00:03:02,029 --> 00:03:05,939 The second element, which is really new, 45 00:03:05,939 --> 00:03:10,000 is that by drilling core samples at the joint lines, 46 00:03:10,059 --> 00:03:11,889 which we opened up like a book 47 00:03:11,889 --> 00:03:16,200 we realized that the interior of these joints 48 00:03:16,200 --> 00:03:19,800 was covered with calcite brought by the movement of water 49 00:03:19,800 --> 00:03:25,500 within the masonry that was pieced together with no mortar. 50 00:03:25,500 --> 00:03:28,500 If the masonry had been put together with mortar, the mortar would have been a sponge 51 00:03:28,500 --> 00:03:30,789 and the water wouldn't have circulated. 52 00:03:30,789 --> 00:03:35,800 Here, it circulates as if it were in a karstic network. 53 00:03:35,800 --> 00:03:38,500 Then from time to time there are resurgences. 54 00:03:38,500 --> 00:03:41,900 It functions like a limestone plateau. 54b 00:03:42,000 --> 00:03:45,800 What are the aggravating factors? 55 00:03:46,000 --> 00:03:48,400 There's a very clear relationship with water. 56 00:03:48,400 --> 00:03:52,600 Stone does not deteriorate if it is sheltered from water. 57 00:03:52,600 --> 00:03:56,800 There's also a relationship with the load: the more substantial the load is, the more the stone deteriorates. 58 00:03:56,859 --> 00:04:03,000 But ultimately, it's a factor that's not that important. 59 00:04:03,000 --> 00:04:09,500 There's another element that comes into play, but it's role is not absolutely clear: 60 00:04:09,500 --> 00:04:11,669 the susceptibility to frost. 61 00:04:11,669 --> 00:04:14,739 Nîmes may well be in the South of France, 62 00:04:14,739 --> 00:04:18,500 but there are quite a few days per year below freezing. 63 00:04:18,500 --> 00:04:22,100 We did some freeze cycle studies 64 00:04:22,150 --> 00:04:27,000 and we observed that there is deterioration, but which remains relatively reasonable. 65 00:04:27,069 --> 00:04:32,500 So frost is only an aggravating factor, and not a decisive factor 66 00:04:32,500 --> 00:04:35,600 because the damage is quite general, 67 00:04:35,650 --> 00:04:38,199 and more or less serious according to the exposure. 68 00:04:38,199 --> 00:04:41,800 If there were certain stones that were sensitive to frost and others not, 69 00:04:41,800 --> 00:04:44,200 a certain type of stone would be damaged 70 00:04:44,200 --> 00:04:51,100 while a whole other series of stones would not be affected by that pathology. 71 00:04:51,189 --> 00:04:57,900 We focused our set of hypotheses 72 00:04:57,900 --> 00:05:03,129 around a combination of causes that would lead to that pathology. 73 00:05:03,129 --> 00:05:08,000 We haven't yet established in what order 74 00:05:08,000 --> 00:05:12,300 the succession of factors produces the result. 75 00:05:12,300 --> 00:05:15,349 We're advancing 76 00:05:15,349 --> 00:05:19,800 but we haven't yet exactly reached our destination. 77 00:05:19,800 --> 00:05:23,100 We know that if we block off the entrance of water from the outside 78 00:05:23,100 --> 00:05:25,100 and the water running inside 79 00:05:25,100 --> 00:05:27,200 we will have resolved, I believe, 90% of the problem. 79b 00:05:27,500 --> 00:05:31,200 Are there any other factors for damage? 80 00:05:31,400 --> 00:05:38,800 The laboratory that worked with us looked at these stones very attentively. 81 00:05:38,849 --> 00:05:44,000 It noticed that there were stone facies 82 00:05:44,000 --> 00:05:47,000 that is the appearance of the stone, 83 00:05:47,099 --> 00:05:51,179 which were geologically different: 84 00:05:51,179 --> 00:05:54,330 some stones contained seashells of a certain kind. 85 00:05:54,330 --> 00:05:56,900 That implies different quarries 86 00:05:56,900 --> 00:05:59,869 or areas in the same quarry that were different. 87 00:05:59,869 --> 00:06:04,219 We're going to continue this advanced research 88 00:06:04,219 --> 00:06:09,100 to see if there's a correlation between the facies of the stone 89 00:06:09,100 --> 00:06:12,700 and the extent of the damage. 90 00:06:12,700 --> 00:06:16,300 But those are all secondary factors. 91 00:06:16,300 --> 00:06:19,539 If there were a certain type of facies that gets damaged and not the others, 92 00:06:19,539 --> 00:06:21,500 we would have noticed that long ago. 93 00:06:21,500 --> 00:06:25,200 It's clearly not the case. 94 00:06:25,279 --> 00:06:29,900 I think that it's really a combination of factors, 95 00:06:29,900 --> 00:06:33,800 which in certain conditions cause this damage. 95b 00:06:34,000 --> 00:06:37,800 What factors have you dismissed? 96 00:06:37,900 --> 00:06:41,040 Yes, there is one element, which is the constraint, 97 00:06:41,040 --> 00:06:44,039 the load on the stone. 98 00:06:44,039 --> 00:06:47,889 At one time, it was thought that the Barutel stone, 99 00:06:47,889 --> 00:06:51,029 which is very strong and can bear a heavy load 100 00:06:51,029 --> 00:06:54,300 when it is wet, the lower part for instance, 101 00:06:54,300 --> 00:06:59,900 would lose 30% to 50% of its load-bearing capacity. 102 00:06:59,900 --> 00:07:05,200 In the work on the first section, some stones were changed, 103 00:07:05,200 --> 00:07:08,900 which exposed the beds of the stone. 104 00:07:08,900 --> 00:07:11,900 On these beds of the stones, there was a kind of edge for adjustments, 105 00:07:11,900 --> 00:07:15,900 and the inside part was hollowed out. So the load was concentrated on these edges. 106 00:07:15,940 --> 00:07:22,500 The accumulation of all of that, along with the stone that expanded due to the effects of humidity 107 00:07:22,580 --> 00:07:24,900 could explain according to some studies which concluded 108 00:07:24,900 --> 00:07:31,000 that this stone 109 00:07:31,000 --> 00:07:34,000 which was weakened by all of these factors 110 00:07:34,000 --> 00:07:37,300 and bearing a significant load 111 00:07:37,300 --> 00:07:40,500 but far from its load-bearing capacity, 112 00:07:40,500 --> 00:07:43,339 that this stone would break. 113 00:07:43,339 --> 00:07:46,300 But the reality we discovered 114 00:07:46,300 --> 00:07:51,349 is that the margin of the bearing capacity is huge, so that can't be the explanation. 115 00:07:51,349 --> 00:07:54,410 We see examples of stones bearing little weight 116 00:07:54,410 --> 00:07:56,499 that are nevertheless very damaged. 117 00:07:56,499 --> 00:08:00,400 There may be perhaps a correlation: 118 00:08:00,400 --> 00:08:03,440 if the stone is bearing a heavy weight, it can be a bit more damaged. 119 00:08:03,440 --> 00:08:06,500 However, it does not get damaged because it's bearing weight. 119b 00:08:06,800 --> 00:08:10,500 How do you define a restoration? 120 00:08:10,600 --> 00:08:16,189 We worked with an Italian restorer, Carlo Usai, 121 00:08:16,189 --> 00:08:19,700 with whom we had worked at the Louvre 122 00:08:19,700 --> 00:08:21,819 and on the tomb of the kings in Jerusalem. 123 00:08:21,819 --> 00:08:25,400 He came to do a cleaning test, 124 00:08:25,400 --> 00:08:28,400 which we could observe because it was done at the ground level. 125 00:08:28,499 --> 00:08:32,700 He also performed joint sealing tests and others with mortar. 126 00:08:32,700 --> 00:08:38,000 That gives a rather good idea of the spirit in which we wanted to carry out the work. 127 00:08:38,000 --> 00:08:40,000 It's a technique. 128 00:08:40,000 --> 00:08:43,800 But it goes beyond the technique: we're trying to manage the image. 129 00:08:43,890 --> 00:08:48,000 The cleaning consists in removing the black, 130 00:08:48,000 --> 00:08:50,500 but we don't remove what are called the oxalates 131 00:08:50,500 --> 00:08:55,000 that is these somewhat orange traces 132 00:08:55,000 --> 00:08:58,200 which are at the same place as the black traces. 133 00:08:58,200 --> 00:09:01,490 We try to not to remove everything. 134 00:09:01,490 --> 00:09:07,200 If you "rewhiten" all of the facades 135 00:09:07,200 --> 00:09:10,500 and in Nîmes, there's lots of sun 136 00:09:10,500 --> 00:09:14,200 all of the hollow parts appear to be very dark 137 00:09:14,200 --> 00:09:18,800 they are accentuated by the shadows created against a white background. 138 00:09:18,820 --> 00:09:25,000 We're tempted to fill in the holes that cause these shadows 139 00:09:25,000 --> 00:09:27,300 and break the architectural lines. 140 00:09:27,300 --> 00:09:35,000 As a result, we slide quite naturally toward increasingly significant reconstitutions. 141 00:09:35,000 --> 00:09:39,700 Whereas, if we don't completely clean the facade, 142 00:09:39,700 --> 00:09:43,000 it appears rather naturally 143 00:09:43,000 --> 00:09:48,000 with lines that compete a bit with the architecture, 144 00:09:48,000 --> 00:09:51,700 but not too much. Which means that we can leave some shadows. 145 00:09:51,700 --> 00:09:54,500 We will work then on the hollow parts of the shadows, 146 00:09:54,500 --> 00:09:59,900 not by filling them in, but by working with the mortars, 147 00:09:59,900 --> 00:10:07,300 in a way that creates an image that it a bit "tighter" than 148 00:10:07,300 --> 00:10:15,500 its current appearance that is distorted by the black and the white traces. 149 00:10:15,500 --> 00:10:23,000 Our goal is to achieve something more homogeneous, while changing the minimum number of stones. 150 00:10:23,000 --> 00:10:27,000 When I say minimum, it's really as few as possible. 150b 00:10:27,200 --> 00:10:31,000 How are your actions inscribed in time? 151 00:10:31,160 --> 00:10:35,000 Of course, in an ancient monument, one must feel the thickness of time. 152 00:10:35,000 --> 00:10:39,500 If the restoration cancels that effect, 153 00:10:39,500 --> 00:10:44,700 you remove a great amount of the value from the monument. 154 00:10:44,700 --> 00:10:48,209 That is even truer when the building is 2,000 years old. 155 00:10:48,209 --> 00:10:54,200 Our analysis has always taken account of time. 156 00:10:54,200 --> 00:10:58,510 For instance, we tried to understand if the areas that were long protected 157 00:10:58,510 --> 00:11:01,200 by the presence of houses, 158 00:11:01,200 --> 00:11:02,800 which had protected the facing materials, 159 00:11:02,800 --> 00:11:11,400 were more exposed to the forces of decay. 160 00:11:11,400 --> 00:11:13,500 It's not completely obvious. 161 00:11:13,500 --> 00:11:22,000 Or rather, was it when the outer arches were re-opened 162 00:11:22,000 --> 00:11:27,500 and these areas were exposed to the rain? 163 00:11:27,500 --> 00:11:29,500 We also tried to understand that. 164 00:11:29,500 --> 00:11:35,500 It's similar for the lower part of the buttresses, which were buried under 1.5 m of debris. 165 00:11:35,500 --> 00:11:38,700 In the photographs taken shortly after the excavation of the Arena 166 00:11:38,700 --> 00:11:44,200 to its original level, we can clearly see 167 00:11:44,200 --> 00:11:47,900 whether or not these stones had been severely damaged. 168 00:11:47,900 --> 00:11:52,300 Apparently, they were not. Yet today, they have been replaced. 169 00:11:52,320 --> 00:12:00,500 Which means that in 100 to 150 years, stones that were relatively well preserved, 170 00:12:00,500 --> 00:12:08,200 because they were buried--thus protected from the cold and the wind--, 171 00:12:08,200 --> 00:12:12,900 as soon as they were unearthed, they deteriorated very quickly. 172 00:12:12,900 --> 00:12:18,500 So we see there is an interpretation of the pathologies over time. 173 00:12:18,550 --> 00:12:22,000 And time is not counted in decades, but in centuries.