Saturday, January 15, 2011
November 26th, 2008
Kaluga, Russia (date listed is the date that the video was uploaded). A crane on rails found a support problem. It's an interesting problem. The crane was working when the underlying support under the bogies with the counterweights gave way. The crane was able to remain standing and I have every confidence that they were able to lift it and get it properly supported again. In the short term they added ecology blocks and wood under the counterweights to prevent it from sinking further.
But what was the cause? I'm actually not going to suggest that it was improper soils, but I'm not a geologist or soils engineer and I haven't seen the ground used because it is covered in snow. I'm going to suggest something else. Water combined with regular freezing and thawing can weaken soils. The water infiltrates the ground, then it freezes which causes the water to expand. As the water thaws and is able to escape, voids are created. Much in the same way pot holes are created in roads, the freezing and thawing cycles of Russia can pose a real problem to be addressed.
The best solution in climates like this is to have a reinforced foundation under the whole of the tracks. That's a bit of a dream solution for many projects around the world. Under cranes on rails for long term installations, I would certainly recommend a complete foundation under the rails. For construction, we just won't get to that level of spending everywhere in the world. Most contractors will have the supports designed to support the rails adequately for typical scenarios and not worry about the "what if's" as much as a professional complainer like myself.
When it comes to setting up cranes, "what if" should be your motto in the planning phase. Just like construction safety in general, always know your escape route before you get into a bad spot. In this case, you should know what your weather extremes are. The most common failure in tower cranes is knowing that wind maps exist, but putting up max free standing cranes in areas with high winds. It would be more appropriate to build it a bit shorter, tie in and climb it to final height if you are exposed to high winds. The point being, consider the weather in the planning phase and you'll save money over time. Safety isn't a sprint, it's a marathon.
You can see a video of the scenario here.
поддержка Калужской кран
Posted by Gaytor Rasmussen at 9:44 AM