fence wall structure

[joncle10]

Hello,

I have a fence wall (small concrete posts 200x200mm and 2 beams spanning between these posts. In between is filled with hollow blockwork. The blockwork aren't attached to the beams. They are just resting on them.
There are some areas in the site where the soil is not the same from the 2 parts of the wall (refer to the attached sketch).
I would like to replace the hollow blocks  by solid ones just in the area of soil height difference since he height difference is only 1meter. Do u think it is an acceptable practise ?
Thank u

 

[BSVBD]

joncle10,

Is your elevation drawing and section accurate, such that, is the height of individual hollow block units, that you typically work with really 0.5m high?

What i don't like is that you say, "The blockwork aren't attached to the beams. They are just resting on them." I believe you should provide some vertical rebar, through the hollow block penetrating at least 6" into each top and bottom beam. At 1m, you are certain to have "some" lateral force at lower course(s). Considering this, solid block would not be practical.

Also, be sure to provide weep holes at or near the bottom course.

Out of curiosity, are your end supports solid concrete columns resting on square footings? How are the concrete beams tied to the two end columns? This appears to be a unique retaining wall method.

 

[joncle10]

Hello BSVBD, thank u for your answer.
Regarding your questions, my sketch isn't accurate. the blockwork I am working with are the standards ones.
The concrete footings are square (the footings were designed to handle the axial load carried by the columns so yes they are centric but the nature of the site made that the soil is not at the same level from both sides.
I will not use solid blocks. i will go with hollow blocks, put some rebars which will be attached to the top and bottom beams and put some concrete in the holes to increase the weight of the blocks embedded part.
i want to check my footings versus overturning. what do you think is the tributary width for such system? span /2 from each side of the footing ?
thank u for the help

 

[BSVBD]

joncle10

Please see attached...

Would you consider a continuous retaining wall like what i've sketched?

Your method seems to be considerably more complicated both to design and construct.

If it's an aesthetic issue, you could install different faced block on the top course. Bottom course appears to be under grade, and, therefore not critical.

 

[oldestguy]

What BSVD is proposing is much simpler, much less cost and faster to build.

 

[joncle10]

BSVBD and oldest guy, thank you for your assist. however, the situation is the following :
Footings have been built and backfilled, columns has been casted with the bottom beam. The contractor is addressing this problem now while it is too late so I am figuring out something which is more or less workable. personally, I would have done a retaining concrete structure and not relied on blockworks.
I will demolish the structure in case the footings are not safe versus overturning or need additional reinforcement. So I am wondering about the tributary width for such a system. any ideas?

 

[BSVBD]

From the information we currently have:

The wall/beam system must be designed by applying your calculated lateral load to the earth side of the combination block/concrete wall/beam.

If this is a simple beam scenario, then, yes, your tributary area or length would be span / 2. But that depends on the varying, high-side, soil heights, and perhaps, other factors, unknown to us.

You then need to transfer your reactions to the cantilevered concrete retaining columns, and likewise, the footings, which, typically, you would have determined prior to designing the columns.

I wish you well...