SIGNIFICANCE OF VERTICAL LEG IN A LEDGER ANGLE WHEN IT IS ANCHORED TO THE WALL 4

[waren1991]

Hi Gentlemen,
I havea situation in a project where I used L4x4x3/8 angle(Toe down) with post installed anchors for a precast landing support.But the engineer later changed the size to L6x4x3/8(Toe down)which I missed to pickup.My Question is,with the vertical leg anchored to the wall(@250mm on centre) does it have any impact whether it is 4" or 6"? & What reason the engineer may say to keep the vertical leg 6". Please help me on this as I have this scenario at significant locations.Thanks. (The offset of anchors from top of horizontal leg(2") & the anchors dia,spacing remains same in the engineer's design.)

 

[GeorgeTheCivilEngineer]

The angle will span between fixing points, but that is not usually significant.

Ease of drilling the hole, putting in the fixing and bolt edge distances are more likely the reasoning.

 

[XR250]

Less prying force on the bolts?

 

[kipfoot]

as xr250 suggests, there will be tension on the anchors. The vertical force on the horizontal leg imparts the tendency for the angle to rotate away from the wall. This tendency is resisted by tension in the anchors.

In a simplistic analysis, the magnitude of the tension force is related to the distance between the anchor centre and the bottom tip of the angle. When you go from a 4" leg to a 6" leg, this distance goes from 50mm (2") to 100mm (4") and the tension is cut in half.