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The iconic Golden Gate Bridge was completed and opened in 1937, forever transforming transportation across the San Francisco Bay. Connecting the city of San Francisco to Marin County, it was considered an engineering marvel at the time and the longest suspension bridge in the world.
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00:00THE END
00:49San Francisco, metropolis of the west, seaport of the Pacific, glories in its calm, landlocked bay.
01:00As far back as 1856, men dreamed of linking the city of San Francisco with the east shore of the
01:06bay.
01:07The steady growth of San Francisco and the Oakland area emphasized the need of communication.
01:14As the years passed, many proposals were made, but it remained for modern science and engineering to overcome almost insurmountable
01:24obstacles and make the dream come true.
01:28Today, there are towers over San Francisco Bay, a realization of the century-old dream.
01:35A six-lane double-deck bridge, eight miles long, connecting San Francisco with the Oakland-Berkeley area, spanning the largest
01:44major navigable body of water ever bridged.
01:50The west bay crossing is a twin suspension bridge with an anchorage in San Francisco, a central anchorage, and another
01:59anchorage on Yerba Buena Island.
02:03This twin suspension span is the largest of its kind in the world and crosses nearly two miles of deep
02:10water.
02:13A tunnel through the island connects it to a cantilever span on the east side, which in turn is connected
02:21to the east shore of the bay by a number of through-trusts and deck-trust-type spans.
02:29Building the cantilever and suspension sections was a challenge to American ingenuity.
02:37A novel method of sinking the foundations was employed.
02:43Steel cutting edges, towed to location between working docks, were built up with hollow steel cylinders.
02:56Wooden walls, the work walls, encased the cylinders.
03:01New units were added at the top as caisson sinking progressed.
03:05This cross-section diagram shows the caisson in position between two working docks.
03:11Air pressure was maintained in the cylinders to control the sinking as concrete was poured into the spaces between them.
03:19On reaching bedrock, the mud was scooped from the cylinders and replaced by a 30-foot concrete seal.
03:32Thus were built the deepest foundations ever undertaken, some as deep as 242 feet.
03:40On these unique foundations, concrete bases were built to receive the superstructure.
03:46The huge steel towers rose like magic.
03:49After years of planning, the visions and blueprints of the engineers took physical shape under the skilled hands of the
03:56men of action.
04:00The bridge men, long experienced in this hazardous business, went about their work, sometimes in precarious positions, expertly guiding the
04:09steel into place.
04:10Some sections weighed as much as 79 tons.
04:24All the steel sections were fabricated at American Bridge Company's plants at Gary, Indiana and Ambridge, Pennsylvania.
04:32That clear there was only one of the biggest named
04:40...
04:45...
04:46...
05:06Looking towards San Francisco from the center anchorage in the West Bay, two of the 500-foot
05:11towers for the suspension bridge can be seen. Looking in the opposite direction past the
05:17other pair of towers, we see Yerba Buena Island, where the great East and West Bay sections
05:23of the bridge are connected by a tunnel. This tunnel, 63 feet wide and nearly as high, has
05:31the largest cross section of any tunnel in the world.
05:38Let's cross to the other end of the tunnel for a glimpse at the East Bay section. Two
05:44mighty piers will support the massive steel towers for the 1,400-foot cantilever span and
05:50its two 520-foot anchor arms.
06:05High above the waters of the bay, the fabricated steel sections swing into place with infinite
06:11care and precision. Building the third longest cantilever span in the world, the longest in
06:18the United States was the bridge men's toughest job.
06:46The last mighty section in the 40 million pound cantilever structure fitted perfectly in the
06:51world. The last mighty section in the 40 million pound cantilever structure fitted perfectly in the
06:51position, surprising to the laymen what expected by the engineers. The remainder of the East Bay crossing
06:59to Oakland consisted of through truss and deck type spans. Back on Yerba Buena Island, work is being completed
07:07on the cable anchorage for the second of the West Bay twin suspension spans. Steel eye bars and a wedge
07:14-shaped
07:14mass of concrete have been firmly embedded in the rock of the island. More eye bars sunk deep in 130
07:21,000 tons
07:22of concrete in San Francisco's Rincon Hill form the western anchorage. The 340,000 ton center pier with its steel
07:31A-frame and
07:31side bars is ready to serve as a common cable anchorage for the twin suspension spans. While signs and
07:38sentinel launches keep bay traffic away from danger, the catwalk ropes are drawn into place. A huge reel of
07:46USS American Tiger brand wire rope at a tower base feeds out above the water toward the center anchorage,
07:531,160 feet away. On the tower, 500 feet above the water, bridgemen adjust and secure the wire rope. To
08:22provide a firm
08:23safe footing, safe footing for the bridgemen, a special type of catwalk was designed. USS Cyclone
08:30chain-link fence was chosen for its light weight, low wind resistance and great strength. This bundle of
08:38cyclone fence will cover a distance of 100 feet.
08:49When sufficient flooring had been placed to reach the next tower, it was stretched into position. This job calls for
08:59iron nerves for the bridgemen ride the catwalk during the stretching operation. But after the precarious footing during
09:07tower erection, this 10-foot catwalk was a cinch. Fun, but with a serious purpose, to keep the wire mesh
09:23sliding freely as it is stretched over the steel rope. San Francisco Bay looked like this from the catwalk. Far
09:33below, the old ferry boat plows
09:34solidly along, soon to be replaced by trains of electric cars, automobiles and trucks, rolling in an endless stream across
09:43the bridge that soars above.
09:50At dinnertime, the bridgemen lose no time hitting for home. A run along the catwalk to whet the appetite, then
09:58the sky ride, and down the escalator helter-skelter.
10:04It's a hard, dangerous job, that of the bridgeman, but he loves it. With catwalks in position, the spectacular job
10:16of cable spinning is about to begin. Giant reels of special bridge wire, supplied by American Steel and Wire Company,
10:24rise majestically to the top of the anchorages.
10:30These huge reels, each carrying 60 miles of wire, were assembled at the nearby Columbia Steel Company warehouse. High above
10:40the water, the spinning wheels begin to travel.
10:4318,000 tons of galvanized wire will be used to bind together two neighbor cities, Oakland and San Francisco. This
10:55cable will consist of 37 strands, each made up of 472 galvanized steel wires as thick as a lead pencil.
11:03In making a cable of this size, the individual wires are not twisted in any way, but laid parallel for
11:10the entire length of the bridge.
11:12From San Francisco to the center anchorage, more than a mile away, and from there to Yerba Buena Island, nearly
11:17another mile away, the spinning wheels work with ever-increasing speed.
11:23This model will illustrate the principle of cable spinning. The end of the wire is anchored temporarily and passed around
11:33the strand shoe.
11:37Then, the spinning wheel takes the loop across to the other side. There, it's removed from the spinning wheel and
11:45looped around that strand shoe.
11:49This is repeated until a sufficient number of wires have been laid. Then, the wire is cut and spliced to
11:58the beginning end.
12:08Day and night, spinning continues. Down plunged the spinning wheels toward the island anchorage.
12:21There, Bridgeman removed the wire and rethread the wheel.
12:41Four cable wires are placed on every trip.
12:45Let her go!
12:51The end of a coil of wire is joined to the beginning of the next coil,
12:55by means of a turnbuckle type splice. Each wire is beveled, so that when they are drawn together by the
13:02turnbuckle sleeve, the ends fit snugly.
13:05The two wires are gripped in separate vices, as a workman draws them up with a wrench applied to the
13:11turnbuckle sleeve.
13:13The beveled ends form a lock, and will not become loose, unless they are again placed in vices and unscrewed
13:20with a wrench.
13:25Two spinning wheels operate on each hauling rope. Halfway between the anchorages, they meet and pass.
13:34A clanking cowbell warns the bridgeman of the wheel's approach, as it continues to spin its web of steel against
13:42the sky, far above the traffic of the bay.
14:04When spinning was completed, the compactor went into action.
14:08Six 75-ton jacks in this machine squeeze and bind the strands into a mighty cable 28 ¾ inches in
14:18diameter.
14:28Special steel castings are spaced at intervals along the cable. Each carries two pairs of steel suspender ropes, cut to
14:37length and pre-stressed to support the bridge deck.
14:45Barges controlled by radio phones carry the massive prefabricated truss units, some weighing 200 tons, out into the bay to
14:54be hoisted into place by traveler trains.
15:00Barges controlled by radio, before crossing the edge of the bay to be hoisted with the bay to be hoisted
15:04with a different vessel,
15:05with a little bit of a trick.
15:18Barges controlled by radio, the flat-like ball from the bay to be hoisted with an important wall.
15:24Barges controlled by radio, the inside and of the bay to be hoisted with a tiny band.
15:39Soon, hundreds of sections had been guided accurately into place in the structure.
15:44An amazing example of coordinated engineering, manufacturing, fabrication, and transportation.
15:55The work of the bridge men is completed.
15:58The rugged men of steel are ready to move on to the next job, wherever it may be, of drawing
16:04together the people of the world.
16:07When they leave, the romance of bridge building leaves with them.
16:12These men of skill and courage are the adventurers whose work and sweat and toil have constructed
16:20a mighty edifice, woven a web of dreams into a web of steel.
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