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Horizontal Point Load attributing to bearing pressure of a retaining wall

Horizontal Point Load attributing to bearing pressure of a retaining wall

Horizontal Point Load attributing to bearing pressure of a retaining wall

I am designing a segmented block retaining wall with a barrier on the top. The top of this retaining wall is a road and the barrier, according to TL-3, will have a 54K horizontal point load to account for the impact from a car. I have designed a spreadsheet that will calculate the bearing pressure if it were just a simple retaining wall with a simple back slope, but I am unsure how to handle the point load in the bearing calculation.

I currently have been attempting to add the vertical point load (Pveh) with the two other horizontal forces from the soils (Ps) and the surcharge loading (Pq) to get a total P. But this approach is giving me bearing pressures that are extremely high which makes me believe I am doing this wrong. If there is any code or material related to this, I would be more than willing to read but I have been unable to find anything so far.

Any help would be much appreciated!

Thank you!

RE: Horizontal Point Load attributing to bearing pressure of a retaining wall

Some questions:
  • What's TL-3? When you throw out publications or codes, not everyone knows what they are.
  • What are you distributing this load over? One foot? Ten feet?
  • You're going to have a hard time resisting a 54 kip load with a lot of your components. Is this hitting a bollard? A concrete wall?
  • Have you talked with the segmental wall manufacturers? They might have some recommendations.

RE: Horizontal Point Load attributing to bearing pressure of a retaining wall

What are the sizes of the "segmental blocks"? What height of wall? For a "high" wall and "small" blocks, you may be asking for the impossible.

RE: Horizontal Point Load attributing to bearing pressure of a retaining wall

-The TL-3 AASHTO code that is just a specific vehicular loading type which gives the horizontal point load.
-I am attempting to design just for a 1' strip but the load is being distributed over a "spread" which is also specified in the TL-3 loading. This gives a load that is distributed over 38' at the total height of
the retaining wall
-It is just a concrete barrier. I have not designed many walls with a concrete barrier on top and am not sure exactly how they are connected to the retaining wall and how they transfer loads.
-I have not yet but I will soon, I just wasn't sure if this was an easy solution that I was just missing.

We are using Recon blocks which are, as far as I understand, fairly large blocks for retaining walls. The total height of blocks is 6.67' but the total height (including concrete and barrier) is 10.5'
The base block has a depth of 45" and weighs about 2500 lbs

RE: Horizontal Point Load attributing to bearing pressure of a retaining wall

In my other post I questioned if the blocks were connected and how's come a vertical load of high magnitude. With that double posting, I mentioned inertia might be a factor, especially if the barrier is a long wall, possibly poured concrete wall. In that case, even with no connections between barrier and the blocks, all you will have going is inertia and that may well be sufficient. In addition the so called horizontal load may be at an angle to the wall, not 90 degrees.

Now if the above is correct as to construction, why not attach anchrage in he top row of wall blocks and then secure reinforcing in the wall to that anchorage. At least then you can substantially increase the inertia resistance to horizontal forces.

RE: Horizontal Point Load attributing to bearing pressure of a retaining wall

well, the horizontal point load will induce overturning and sliding - this should come from a basic statics analysis of the wall. 54K as in kips? Does that include the impact factor? If you bearing pressures are too high, your footing is probably too small. Also, segmented block? I intuitively do not see segmented block taking 54 kips - that sounds like it needs to be a cast in place wall

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