0 00:00:08,505 --> 00:00:10,797 - So I mentioned that the Bayonne Bridge was the longest 1 00:00:10,797 --> 00:00:13,326 spanning arch bridge in the world when completed, 2 00:00:13,326 --> 00:00:17,333 but so was the George Washington Bridge, right behind me. 3 00:00:17,333 --> 00:00:21,332 How is it that we got to this span of 3,500 feet, which was 4 00:00:21,332 --> 00:00:24,132 an enormous span, remember that the Brooklyn Bridge, 5 00:00:24,132 --> 00:00:27,823 that we just spoke about, was 1,600 feet in span, 6 00:00:27,823 --> 00:00:30,765 and that was tremendous, that was just unbelievable 7 00:00:30,765 --> 00:00:34,344 for the people at the time to see a bridge of that span. 8 00:00:34,344 --> 00:00:37,246 Now at the time that proposals were being put forward 9 00:00:37,246 --> 00:00:40,614 for crossing this Hudson River, the longest spanning bridge 10 00:00:40,614 --> 00:00:43,095 in the world was the Benjamin Franklin Bridge, 11 00:00:43,095 --> 00:00:46,938 and that span was 1,750 feet. 12 00:00:46,938 --> 00:00:51,895 So we needed to go from the longest spanning 1,750 feet, 13 00:00:51,895 --> 00:00:56,011 to on the order of 3,500 feet. 14 00:00:56,011 --> 00:00:58,835 I have a great colleague, Steve Buonopane, 15 00:00:58,835 --> 00:01:01,702 at Bucknell University, and he put together this plot 16 00:01:01,702 --> 00:01:03,989 that I'm showing on the screen right now, 17 00:01:03,989 --> 00:01:08,722 which shows the different span records for the years. 18 00:01:08,722 --> 00:01:13,073 So we see that every year, the record span increases just 19 00:01:13,073 --> 00:01:16,440 a little bit and a little bit more and a little bit more. 20 00:01:16,440 --> 00:01:20,566 So we have the Brooklyn Bridge reached record, 21 00:01:20,566 --> 00:01:22,190 and then the Benjamin Franklin Bridge 22 00:01:22,190 --> 00:01:24,544 reached the world's record, 23 00:01:24,544 --> 00:01:28,021 but to get to cross this river, we see the tremendous jump 24 00:01:28,021 --> 00:01:32,167 that we need to make, so it was a huge leap in engineering 25 00:01:32,167 --> 00:01:36,984 to jump from on the order of 1,700 feet to 3,500 feet. 26 00:01:36,984 --> 00:01:39,944 Ammann had to essentially double the record 27 00:01:39,944 --> 00:01:42,316 for the world's longest span. 28 00:01:42,316 --> 00:01:44,845 So how did he do that, and what was he thinking? 29 00:01:44,845 --> 00:01:47,551 Well here's an image of his vision 30 00:01:47,551 --> 00:01:50,021 for the Hudson River crossing, it was a vision 31 00:01:50,021 --> 00:01:54,441 of a suspension bridge with stone towers. 32 00:01:54,441 --> 00:01:56,022 But how did he get there? 33 00:01:56,022 --> 00:01:58,355 He was working for Lindenthal at the time, 34 00:01:58,355 --> 00:02:00,927 and Lindenthal had put forward proposals, remember he had 35 00:02:00,927 --> 00:02:04,566 a proposal in the book by Wilhelm Ritter in 1888 36 00:02:04,566 --> 00:02:07,573 for crossing this, and in 1920, he'll put together 37 00:02:07,573 --> 00:02:10,268 another proposal, but all of these proposals were 38 00:02:10,268 --> 00:02:14,027 for railroad bridges, Lindenthal was in the railroad age 39 00:02:14,027 --> 00:02:16,687 and he wanted a railroad bridge. 40 00:02:16,687 --> 00:02:20,165 And this bridge that Lindenthal was proposing to put forward 41 00:02:20,165 --> 00:02:23,902 was going to be very large and very expensive. 42 00:02:23,902 --> 00:02:26,708 So as I mentioned, in 1888 Lindenthal put together 43 00:02:26,708 --> 00:02:29,168 a proposal and then there were several other people 44 00:02:29,168 --> 00:02:32,735 who put proposals, there was another one in 1889 by others, 45 00:02:32,735 --> 00:02:37,607 others, 1893, another proposal by others in 1894, 46 00:02:37,607 --> 00:02:42,123 1896, another one, 1913, so you'll see these images 47 00:02:42,123 --> 00:02:45,447 of the different ideas and different proposals 48 00:02:45,447 --> 00:02:48,626 but they were all very long spanning bridges 49 00:02:48,626 --> 00:02:51,063 crossing the Hudson River. 50 00:02:51,063 --> 00:02:54,735 In 1920, Lindenthal put forward another proposal 51 00:02:54,735 --> 00:02:58,528 and he and Ammann worked on this proposal 52 00:02:58,528 --> 00:03:00,569 for several years. 53 00:03:00,569 --> 00:03:03,098 Lindenthal needed to raise money for this proposal 54 00:03:03,098 --> 00:03:06,205 for this bridge to be built, so he put together a company 55 00:03:06,205 --> 00:03:08,399 called the North River Bridge Company 56 00:03:08,399 --> 00:03:11,619 and started raising money privately for the design 57 00:03:11,619 --> 00:03:13,690 of his proposal for this bridge. 58 00:03:13,690 --> 00:03:15,673 So Ammann is working with Lindenthal 59 00:03:15,673 --> 00:03:19,103 from 1920 until 1923 60 00:03:19,103 --> 00:03:22,813 on Lindenthal's plans for this gigantic proposal 61 00:03:22,813 --> 00:03:25,300 of the Hudson River crossing. 62 00:03:25,300 --> 00:03:28,834 But Ammann grows concerned, he's concerned because, first, 63 00:03:28,834 --> 00:03:33,101 of the huge cost of this bridge, Ammann knows that the cost 64 00:03:33,101 --> 00:03:36,679 of Lindenthal's proposal is tremendous and is not optimistic 65 00:03:36,679 --> 00:03:39,534 that Lindenthal will be able to raise the funds 66 00:03:39,534 --> 00:03:41,683 for this massive bridge. 67 00:03:41,683 --> 00:03:44,914 Also there is a reluctance from the railroads to committ 68 00:03:44,914 --> 00:03:48,750 to using the bridge, and then finally, there's opposition 69 00:03:48,750 --> 00:03:51,401 of the Manhattan businesses, because there would be 70 00:03:51,401 --> 00:03:54,041 twenty lanes of traffic entering mid-town, 71 00:03:54,041 --> 00:03:57,162 which was the proposed site of Lindenthal's bridge, 72 00:03:57,162 --> 00:04:00,007 Lindenthal proposed that the bridge be built at mid-town. 73 00:04:00,007 --> 00:04:03,826 So many businesses were concerned they would need that 74 00:04:03,826 --> 00:04:07,987 land space now for that railroad to pass by. 75 00:04:07,987 --> 00:04:10,593 So for these reasons, Ammann was concerned. 76 00:04:10,593 --> 00:04:13,309 What did he envision, what did Ammann want? 77 00:04:13,309 --> 00:04:15,885 He wanted an automobile bridge, he was trying to convince 78 00:04:15,885 --> 00:04:19,100 Lindenthal that the time was now to build an automobile 79 00:04:19,100 --> 00:04:21,640 bridge not a railroad bridge, and to build it 80 00:04:21,640 --> 00:04:24,904 in northern Manhattan where land was less expensive, 81 00:04:24,904 --> 00:04:26,700 not in mid-town Manhattan. 82 00:04:26,700 --> 00:04:29,070 So he tried to convince Lindenthal of these ideas 83 00:04:29,070 --> 00:04:32,865 but Lindenthal was still supportive of his own ideas, 84 00:04:32,865 --> 00:04:36,579 his proposal for a railroad bridge in mid-town. 85 00:04:36,579 --> 00:04:39,713 So Ammann can't convince Lindenthal of his ideas, 86 00:04:39,713 --> 00:04:44,024 and in 1923 he leaves Lindenthal's company 87 00:04:44,024 --> 00:04:46,356 and begins a period of unemployment 88 00:04:46,356 --> 00:04:49,353 and during this period of unemployment, Ammann continues 89 00:04:49,353 --> 00:04:53,481 to work on his ideas for the design of what we now know 90 00:04:53,481 --> 00:04:56,443 to be the George Washington Bridge. 91 00:04:56,443 --> 00:04:59,715 So next, let's look at the scientific, social, and symbolic 92 00:04:59,715 --> 00:05:02,505 aspects of the George Washington Bridge 93 00:05:02,505 --> 00:05:06,395 and see how Ammann was able to not only design this 94 00:05:06,395 --> 00:05:09,873 from an engineering perspective, but also, from the social 95 00:05:09,873 --> 00:05:12,634 part of the story, convince the politicians 96 00:05:12,634 --> 00:05:15,057 and the community about this bridge 97 00:05:15,057 --> 00:05:18,702 and this idea that he had.