Whats being fenced in a prison or a scrap-yard?
You need to take earth pressure, water pressure, and surcharge load for surface loads applied to the retained soil. Assume the earth and water load the wall with a 45 degree triangle of load, and the earth load is further reduced by its angle of friction (usually around 30 degrees). Best to assume a worst case of non cohesive soil (gravel).How do I actually calculate what is required.......it seems like a bit of guess work but there must be a simple calculation that allows me to design a wall that is actually suitable.
I'm a mechanical engineer by trade and understand the principles, but how do I come up with an exact number I need to acheive.
Thanks,
Ant
In total it cost about £6.5k some £14k cheaper than standard retaining wall we were quoted for.
You need to take earth pressure, water pressure, and surcharge load for surface loads applied to the retained soil. Assume the earth and water load the wall with a 45 degree triangle of load, and the earth load is further reduced by its angle of friction (usually around 30 degrees). Best to assume a worst case of non cohesive soil (gravel).How do I actually calculate what is required.......it seems like a bit of guess work but there must be a simple calculation that allows me to design a wall that is actually suitable.
I'm a mechanical engineer by trade and understand the principles, but how do I come up with an exact number I need to acheive.
Thanks,
Ant
Once you've done that you can work out the moment to the wall, and design it to resist that moment.
Then you should check bearing pressure (axial load to base plus pressure induced by the moment.) Should usually be limited to around 100kN/m2 maximum.
Then check overturning by assuming it will rotate about the front of the footing due to the moment. But the self weight of the wall and any other load directly over the footing will resist overturning. A factor of safety of at least 2 is usually assumed.
Then you should check for sliding. You've got the horizontal loads from the applied pressures resisted by the axial load to the footing. A frictional coefficient of 0.4 is about right.
It would be difficult to calculate the effect of the horseshoe by hand but it will definitely help.
I would think 12mm bars at 200mm crs would be sufficient for a 1340 high wall, and I'm sure Tony's 1m long base would be enough, but if you do want to try the calc I can send you an example.
Friend request me and I'll email it to you, althoug at 900mm high in clay they are usually not designed, and it's just ensured that the depth is 4 x the height and the foundation is adequate.Please send an example it well worth knowing for the future. I did some level checks the other night wall needs too be 900mm high and the ground is clay. When I dig I can hardly shovel it cause it comes out in big lumps. I have to hand ball into the wheel barrow!
There really impressive! I like the idea.
What's behind the fence? Did you have a structural engineer design it?
Ant
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