This is sheet number 1 of Leon Moisseiff's 39 sheet blueprints for the 1940 Narrows bridge. The title sheet lists the entities involved with this design, and the descriptions of what was on each sheet.
Sheet 4 of Moisseiff's plans is of the General Layout, with overall dimensions of the Towers placement, length & width of the bridge, and the look of the Narrows channel bottom with each shore & hillside. Looking at the top (overhead) view of the bridge deck in the upper part of this plan gives an idea of just how long, and extremely narrow the bridge was.
An interesting elevation is contained on sheet 28. It shows Tower #3, which is still in existance on the Gig Harbor shore. This is what it used to look like when it supported the 1940's 2-lane road deck. The conversion from this to a wider 1950 4-lane Tower #3 is shown near the bottom of the page.
Sheet number 29 of Moisseiff's design for the superstructure shows details of the immense sized cable saddles that held the main cable on top of Towers #4 and #5, and part of the cable bands that held the main cable together, as well as holding the suspension cables which were connected to the road deck.
Another plan, this one being number 30, shows more details of the various sized cable bands and accompanying brackets which the suspension cables & cable ends were fastened to.
Sheet number 35 features the overhead view & elevation view of the Tacoma anchorage structure. The 2-lane road from the bridge leads onto the anchorage, where the road widens as it approaches the Toll Booth facility. As the driver exists the toll area (or before entering depending on which direction of travel) the structure had a driveway all the way around it which led to the viewing area, and parking lot. The morning of Gertie's collapse in 1940 there were several cars parked in this viewing lot. Fortunately, nobody was injured, but if people happened to be in their car, and were under the span at the time- they must surely have feared for their lives.
Towards the end of his set, and the last of this selection of Moisseiff's plans presented, is sheet number 38. It contains some of the electrical plans, including a lamp post design that was never to be. His vision was to have graceful arcing poles leading to sodium vapor fixtures. Instead, by the time his plans were revised for the superstructure, and it was finally built; the poles ended up being straight gothic/neo classical style, though Moisseiff's thought of sodium vapor fixtures was utilized.
The next group of plans are from Clark Eldridge. They are technically called "Linens" rather than "blueprints" because they were not run thru a blueprint machine. If you have never seen an original drawing turned into a blueprint, it is really interesting. An architect or draftsman (now we have AutoCad and other computer programs that do this step) produces an ink plan on drafting paper. This plan is placed into a blueprint machine that reproduces the drawing on thicker paper with a blue background, and white linework. Blueprints can be made in any quantity desired. These linens were not produced from a blueprint machine, but rather copied from the original line drawings.
This an overhead view of the Tacoma & Gig Harbor area, with the Narrows waterway which the bridge spans.
As compared to Leon Moisseiff's 39 sheets, Clark Eldridge got down to the smallest details with his plans totalling 158. This represents thousands of hours of work just to design the bridge on paper.
The plan seen above shows the road deck construction, and assembly details at the main span of the bridge. The 1940 construction was made easier than the 1950 bridge, in part because the deck sections were pre-made, and then lifted & fastened in place. Much of the plan useage was at the steel manufacturers plants. The 1950 bridge was more difficult to build due to the fact that it was assembled from mostly stock pieces.
Seen here is a plan of the large cable saddles that held up the main cable, and one of the larger size cable bands.
A detailed plan of the large & small cable bands, as well as their placement position along the main cable.
Several plans were necessary to show all the fine details, which not only told the manufacturers the exact specifications of the components, but also told the construction men how & where to install them.
This interesting plan is of the Gig Harbor supports, which are called Bents No. 1 and 2. The term Bent refers to a shorter support that does not require the same structural complexity as a Tower does. These Bents still exist where they have been since they were built in 1939, though the members & fasteners have been improved & replaced to support the 1950 construction.
The plan seen above shows the placement of Bents 1 & 2, and Tower #3 on the Gig Harbor hillside. All 3 supports have concrete footings that are similar to the foundation of a building. A hole is dug first, then rebar is placed, then the concrete is poured, with the shape being footings and the base rising above the ground level- just like a building's foundation.
The Tacoma and Gig Harbor anchorage structures were very much influenced by graceful angles & lines of the 1930 era. The plan of the Tacoma side's anchorage & toll facility structure seen above shows the combination of sweeping horizontal & vertical lines in the concrete.
The original intent for the landscaping, as seen above, was very beautiful; with rows of hedges and trees in manicured planter beds. Unfortunately, right after the bridge was completed in July, the focus was diverted from finishing the landscape to stablizing the Galloping part of Galloping Gertie. The landscape work never was finished, and soon after the fallen bridge was dismantled the entire anchorage structure, along with these plans for landscaping- were torn up.
The landscape design was meant to be low maintenance. This plan was for an in-ground sprinkler system. Again, this was never installed. This concludes the selection of Clark Eldridge's plans.
The next group of linens & blueprints are from Bethlehem Steel. This was & is one of the largest manufacturers of many components. They have been involved in the construction of many bridges across the country, and for many decades. The linen seen above shows the details of the turnbuckles, which kept tension on the numerous cables across the bridge.
Another highly detailed plan shows various stanchions, a hand rope support, and a suspender clamp. Every single part has an important task in keeping the bridge together.
The above torpedo shaped parts are cable sockets. At the end of each suspension cable these sockets were placed, and the sockets in turn would be fastened to girders or supports. Many hundreds of these were made- most all of them ended up at the scrap metal recycling during World War II after the bridge fell.
This plan is of the all important bases of the main Towers; #4 and #5. Each Tower leg was a cross shape, with an elevator inside one of the four sections of each leg. The cross-members seen between the Tower legs provided strength and stability, as well as a platform for the road deck.
The Tower top is seen here, with the cable saddles on the top of each leg. In addition to the saddles, a safety beacon light was placed on top of each, and it was necessary to keep those lights in working order so airplanes did not hit the bridge. Keep in mind that the Tacoma Airport is located just to the southwest of the bridge, so air traffic in the area is common.
This is a neat look at the cable splay layout, which is not seen by anyone but the maintenance workers- as the main cable ends are located under the bridge, and inside the anchorage structures. Each of the main cable's strands are separated from the last cable band, and attached to the anchors where they can be adjusted for tension.
The above plan identifies where each main cable's hand "rope" stanchions & brackets were to be fastened on. The term "rope" really refers to the cable that the workers held on to as they travelled on the main cables. The material was not really "rope" as that would have deteriorated in a short time.
Here is the roadway design. The span's deck was made in sections of I beams fastened together, with diagonal bracing, and the solid sides that caused so much turbulence from the wind hitting it, that it could not withstand the continued wind.
The cross section above shows the road deck. It includes the roadway of two lanes width, a sidewalk on each side of the road, and the hollow space between the large framing below the road. Picture this flimsy construction traversing a mile's distance. Not a sound idea for stability.
Girder placement is seen at the top of this plan, with the framework of Bents 1 and 2 in the middle of the plan. At the bottom is an interesting look at the girder sections as they were to be put together; with the center sagging- near the ends were raised, and the very ends were dropped at a low angle. This is how it really happened, and when the load was put on it, the sections levelled out. After the road received the concrete surface this level ended up as a gentle arch.
If you were to dive down into the water, this is what you would see around Pier 4 during the construction. The above plan shows the anchors placement for the caisson as it was being lowered into the water, and settling into the bottom. It is astounding how precise this process is, given the immense size and weight of each caisson.
The caissons were (and still are) massive size covertable bases that hold each pier. They started out to be floating shells, so that they could be calculatingly lowered into the exact spot they needed to be. Once they were correctly placed, the bottom was filled with concrete, and the rest was flooded with water. The top of each was capped with concrete, which became the pier tops you see above the waterline. They still to this day, are hollow inside, but made so strong that they should not fail. This is the end of the Bethlehem Steel selections.
Switching now to Pacific Car & Foundry's plans for the Pacific Bridge Company, the above blueprint shows the anchor placements around a caisson. Other details are also shown on the plan, including a part of construction that was voided. Any and all plans were subject to modification or change, depending on the jobsite needs.
The above plan is of a work trestle located around Pier 3. Even various things such as this platform, and other important working structures that were not part of the bridge- but needed to build it, were designed & made from plans.
The last of this group is somewhat hard to make out, but it is the excavation plan for what would become Pier 3 on the Gig Harbor shore. Again the construction involved digging a large hole in the ground, but this location, being right next to the tide, and sometimes under the tide- meant it was filled up with ocean water as it was dug. Another difficult accomplishment was building a pier base in the water. The original Pier 3 base built in 1938 is still there, but it was built up with more concrete in width, depth & height to support the 1950 version of Tower 3.
This plan shows the changes that were made to Tower 3. The solid outer lines are how the Tower concrete base is today, i.e. the modifications that were made in 1949. The inner lines show the smaller version of the same Tower base from the original construction. Interestingly, the original base was left in place at the very bottom, and in the 1949 additions the base was only excavated down to a point, then stopped short of reaching the full depth. Also note that the Tower legs received an additional cross-member halfway up, and at the top too, as well as receiving additional width at the top.
Though the Tower has seen nearly 70 years of use, it still remains intact. The photo on the left is from about 1942, taken by Frank Owen Shaw, and provided courtesy of the Harbor History Museum in Gig Harbor, Wa. This was right after the middle span was removed, and it shows the stark void left behind from the Gertie bridge removal. The photo on the right was taken in 2007, to show viewers the differences on the same tower. The chain link fence is there to keep people from attempting to climb up, as well as protecting the access door near the bottom of one leg, which leads to the ladder inside.
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