Arena models (2) – raising stairway

This second model will be filmed for integration with other footage as for the first (main stage ramp) model but, in addition, model details are planned to become “stars in their own right” — showing what the audience never saw behind the scenes — “below the surface“.


Technology: SOUND/VIDEOmain RAMPSTAIRWAYSoverhead CABLES
Models: main RAMP, STAIRWAY
Project: home.


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Raising stairways are located at the north and south ends of the arena; the south is more complicated with a vehicle down-ramp from stage level to exit level, and below that is a foot access to the ramp of the LED central stage (for the soldiers for example).

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The two main elements are (1) the supporting girder structures and (2) the two-section stairway which provides normal entry (shown in the image above) and very high entry when the two parts are opened together.

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Construction of all these models begins with critical measurements and learning how things were put together, taken mainly from photographic material.  Our video and photographs were taken on 20 or more visits to the construction site, the actual show, and four months extra of de-construction. Published aerial photos shot directly above the arena provide useful macro ratios and dimensions.
Below, ⬇ a cross section from the beach at the south end to the main stage ramp at the arena center — the photo shows the raising stairway at the center of this cross-section. ⬇

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The main stage ramp pit was dug December 2018 then covered up until January: this shot, taken over that holiday period, along with parking space markings as an embedded scale, provides quite accurate size information.  ⬇

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Next images show base of the large south stairway support  (we can just make out foot entrance to the main stage ramp), and to its right a view underneath the stairway construction.  ⬇

Comparing reality with our model: we do not model the scaffolding, only the major structural elements.  ⬇

Foundation for this model is “ground level” the raising mechanism will be below ground, as will visibly be the foot entrance to the main stage ramp. We begin by precisely placing blocks for the two support structures, as was done very early in the real construction. These blocks are sturdy — our estimate by comparing relative height with the girder structures they support, is that they are each 75cm high and 3 meters long. ⬇

As we researched our photos ready to build the stairway model,  we uncovered the complex nature of the pedestrian entry to the main stage ramp.⬇ Necessity for this re-enforced concrete shape became clear once we realized just how much supporting scaffolding was required to build up the arena seating and stages — we thus believe that the primary purpose of this groundwork was to maintain a clear space and to guide performers onto the ramp — particularly for the 200 soldiers who needed to enter quickly in formation, four across, and with tall staff rods. This method would have allowed them to assemble and enter the ramp two from each side. In one scene, they entered five across – extra complication.

The vehicle ramp below the stairway is integrated with the support girders (grey) and the arena’s metallic framework structure (rust). ⬇ The main stage ramp is visible in the background.

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At times construction of the model’s working parts feels like watch-making ! ⬆
Tolerances for the pivots are quite tight to correctly position the stairway and to avoid any side-ways movement. On the prototype this part is relatively small and seemingly inadequate – our model pivot is perhaps minutely over-scale, but it works well. 

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The heavy steel counterweight  is prepared. ⬇ Each weight of the model weighs 350g (700g the pair), which corresponds to the weight of the combined upper and lower stairways. Each weight is made up from 4mm steel, 3cm x 12cm, a sandwich of three plates. ⬇

It turns out that the tiny supports for the counterbalance weight took more care than expected:

— Stairway model, construction highlight —

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“Pistons” installed on the lower stairway – shown above ⬆ in the “up” position. In this view we see the quite complex access options of the arena “south end”: the two-section raising stairway with a vehicle down ramp below it, and the pedestrian entry to the main stage ramp.

With the enclosing sides added to the vehicle down ramp, we compare here the real (left) with the model. ⬇ The tiny Sony RXOII camera is used to navigate inside the structure.

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Lower stairway “pistons” shown ⬆ in the “up” position. This moment in construction is a special one, being the very first time that the lower stairway is self-supported and to note that the model is very stable with no side-ways movement; due in part to the close-tolerance pivots used on both sides. ⬇ This stairway opening height can be adjusted by turning the “pistons”. ⬇

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Under-stairway view ⬆ showing both “pistons” raised – still a lot of work to do but already giving some ideas for video integration.

And a first view ⬇ of the fixed stairway surrounding the raising portions – the stairway now awaits the “steps” on top of the supporting structure. This view is taken from the top of the main LED stage ramp, thus now connecting the main stage and stairway models.  ⬇

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Another first during the model construction: both upper and lower stairways raised together.  ⬇  The lower stairway remains in its own down position, the two are raised together when the upper pistons are activated. The upper stair “pistons” are now in place – first images below. Manual smooth lifting for filming the raising motion is also tested.

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Comparing “north” and “south” ends of the arena.

Our model is of the “south” end which is the more complex of the two stairways. Here we see structural differences (move the cursor to compare). The “north” stairway construction has two support sections above ground level versus three for the south. Due to the land slope, the north stage is closer to ground level, has a very short down-ramp and no beneath stage access.

Left: South — Right: North

Technology: SOUND/VIDEOmain RAMPSTAIRWAYSoverhead CABLES
Models: main RAMP, STAIRWAY
Project: home.