Wall curvature tips, anyone?

iplogger1

The chap who is doing site clearance and landscaping for us
is interested in digging the foundations for our front wall.
Most of the frontage will run in a straight line taking a
14.5 inch minimum clearance from the public road as
a guideline. The wall runs roughly west to east as you
look towards the house. The gate entrance would be sited
at the tail of the east end. I've sketched out the curvature
of the wall as it slopes into the gate pillars. The desired
curving is convex.

A relative told me that a lot of folks use a regular circle
for their wall curvature and this gives a fairly acute bend
in the wall. He felt I'd be better to sketch it out as an
ellipse adjusting the minor/major axes to scale with
offsets we measured for the placement of the gate pillars.
I can draw this out with standard MS draw package.
I could take locus points every metre or less and give
those to the landscaper/wall foundation digger guy and
spray paint the guide points or use a bag of lime.

Does anyone know of a better approach ? What I am after
is a very slack curvature so that the visibility is maximised
as a car exits the property. I don't have autocad, btw.
My relative (who is a mine of historical information) told
me that in older days engineers uses piano wire to mark
out curved areas on account of it's flexibility,etc!!

~ipl

Qwerty?

Send on the measurements and I'll draw it up, and call round to show you haw to mark it out.

Q?

Alun

A common way of drawing ellipses that I use for marking ellipses on wood panels in preparation to cutting them on a bandsaw is to place two nails at the foci of the ellipse, take a loop of string and place it round the nails. Take a pencil and use it to make the string loop taut. By moving it along the string, keeping it taut all the time it will describe an ellipse. By varying the length of the loop of string you'll change the eccentricity of the ellipse.

Scale the whole thing up, and substitute stake for nail, rope for string and spray paint for pencil and I reckon you'd manage to draw a pretty good curve.

Mellor

There is a very simple way to do this. A circle is a simple ellipse, where every point on the curve is a set distance from the centre.
An ellipse has two centres called focus points. Every point on the curve is a set distance from these point combined.
Two stakes in the ground at each of the foci and a lenght of rope equal to the major axis and you can mark a near perfect ellipse.

If you still dont get it look here = http://johnbanks.maths.latrobe.edu.au/Games/Ellipse/

i can explain how to set it out if you like.

Mellor

damn, beaten by one minute

iplogger1

Declan, I've sent you a PM.

Thanks for all the replies.

~ipl

ircoha

iplogger1 wrote:

The chap who is doing site clearance and landscaping for us
is interested in digging the foundations for our front wall.
Most of the frontage will run in a straight line taking a
14.5 inch minimum clearance from the public road as
a guideline.
~ipl

That right?

iplogger1

ircoha wrote:

That right?

no, -- sorry should have read 14.5 feet - I meant to correct that.