Holdfast Training Services Trial Blog

I am beginning to dread Monday mornings!We are just about to backfill the core and are in the middle of a commercial minefield.  We have 50% of the footings complete and 30 % of the slab on ground, with the southern half of the site still bare rock and some more excavation to get down to bulk.

I am dealing with the restraint of the secant pile retaining wall on my site and I was asked to look at a build sequence to remove the anchor waler, that is going through the strip retaining wall.  The very helpful wall designers then told me that I had to build the slab above then remove waler. Now this is designed as a slab on ground and the area in red needs to be backfilled.  So I challenged that I only had to backfill to the bottom of the waler with compacted fill- They conceded.

Hurrah – smug for no reason, I go about my business until one of my cadets asks me how the wall is tied into the central core as there are no details of the connections.  Now I am not in charge of this wall as it belongs to the ‘lone ranger’ but, he wasn’t interested in what cadet had to say (the cadet is exceptionally bright).  I also know this wall is 18 m long and nearly 3 m deep and cannot be supported by the lift core and the secant pile wall.  So how is it supported?

Smelling a rat -I check with the Project Engineer who tells me it doesn’t need to tie into the core as it is supported by the slab on top and bottom.  What did they miss and how should I solve the problem?  I look forward to hearing your suggestions.

Plan view here S-CD-10-001_3-Markup Retention wall

New proposed build sequence