Why was this done? (picture included)

[AndrewPatrol]

Could it be that 90 x 35 is treated pine ???????????? could it be that they are for the plinth boards and the round posts are for steps or deck as previously mentioned. I thought ant caps are only semi effective anyway, I'd imagine termites can build their mud tubes around quite easy.

[boban]

If you have a look the manner in which the 90x45 is fixed, you could only imagine it to be temporary. It has been used so that the post can be fixed at a certain height and plumb whilst the concrete has been placed.

The height of the posts indicates to me that a deck is to be placed there. I may be wrong, but we'll see. No chippie or builder would do that as a permanent structure.

[DvdHntr]

Treated only means they won't attack that piece of timber but it will still act as a bridge.