The Weight-bearing Capability of Victoria

by Li Shu-juan
Xi'an Botanical Garden, Xi'an, China
Click images to enlarge

In 2005 at Xi'an Botanical Garden, we proved that a Victoria pad could bear the weight of a lady and two children! Let me tell you how we did it.

I had heard, even before I worked on the cultivation of Victoria, that someone calculated that a pad of Victoria could bear 75 kg (165 #) by "the experiment of overspread sand". When I set a child weighing 25 kg (55 #) on the pad, the place under the buttocks of child broke. Why could the pad bear 75 kg but not a child weighing 25 kg?

Analyzing the reasons, I thought "In the experiment of overspread sand, the sand was distributed evenly, but when the child sat on the pad, he only touched the pad with his buttocks and feet -- his weight pressed on only 400 cm2 (62 "2) of the pad. The main reason for the damage to the pad was that pressure was too great on one part of the pad, but that should not affect the overall weight-bearing capacity." So, I devised a method of distributing the pressure.

I found a circular foam plastic board, with a thickness of 5 cm (2") and diameter of 120 cm (47"). I swathed it with yellow-green cloth to prevent the board and feet of children from injuring the pad and also to match the yellow-green of the pad. We put the board on the center of pad, then took each person onto the pad one at a time. First, we took the child weighing 25 kg onto the pad, which was not damaged. The diameter of this pad was 180 kg (71").  

Several days later, a lady weighing 45 kg (99 #) stood on a pad with a diameter of 189 cm (74.5"). This time we put a small foam plastic board under the feet of the lady. Water soon infiltrated onto the pad because of the added pressure in the center.


Grand total weight
79 kg (174 #)
After about 20 minutes, a lady weighing 46 kg (101 #) and two children both weighing 16 kg (35 #) were placed on same pad, for a total weight of 79 kg (174 #). The pad was still unscathed. Only a little water infiltrated onto the pad after five minutes.
We had succeeded, because the weight of the people and the board were dispersed to a larger area of about 1.13 m2 (12'2). However, when a lady weighing 60 kg was taken onto the pad, the board was about to break.  

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