I have been asked to monitor approx 5,200 feet of a block retaining wall. I need a point at the top and a vertical point near the bottom of wall. I am looking for suggestions of what kind of vertical point to use. I was going to use a small thread rod with a hex bolt.
Couple of questions first. How high is the wall? Is it concrete block or keystone block or gabion? On a couple I have done we used all weather prisms, glued bicycle reflectors on the wall or building or set points on the structure and located with prism. If you can set permanent targets on structure and then initial base line control, it becomes a one man operation for monitoring over a period of time.
Concur and add that the placement of base line control needs consideration.
RADU
See the thread a while back about reflective tape
> Couple of questions first. How high is the wall? Is it concrete block or keystone block or gabion? On a couple I have done we used all weather prisms, glued bicycle reflectors on the wall or building or set points on the structure and located with prism. If you can set permanent targets on structure and then initial base line control, it becomes a one man operation for monitoring over a period of time.
There is a total of 11 keystone block walls on site that vary in height, the tallest being 25'
Done a fair share of this stuff here.
Have they conveyed exactly what they are expecting you to monitor and what outcomes they are hoping to achieve?
I'd ensure I fully understand what they are needing, not what they 'think' they want.
That has always been my first question and it does pay to ensure they and you both have same understanding.
(one real problem I encounter is third party involvement where someone in 'the office' requests the work on behalf of an engineer and that's when I ask to speak to the bod that asked for and will be using the information.)
We had one site that the weight of what we were monitoring actually made the whole area, not just the immediate site sink. It was well off a river but an old flood plain.
We soon realised, but our control was going down too. Very helpful.
As Radu said, and in light of my previous comment I'd give serious attention to any baseline, referencing marks etc.
That's a very long line.
Just out of interest. How do you/ others report an ongoing monitoring survey?
I had one job where I had to monitor cracks in a brick house and the changes varied across the building and in time.
Wasn't easy to report. Easy to survey.