Bridge Layout Question 1

[Drumchaser]

I used to do layout early in my career, before I got lazy.
I have always dreaded skewed bridges, and has been quite some time since I have visited this. The Plans include a Begin Bridge Elevation at each end (Fin. Grade) and include the bearing seat elevations. (this is standard in our plans) Excluding the use of Microstation or a CAD type system I have always used triangles to check the seat grades and calc. the top of shaft or piling elevations. The problem is this is very time consuming and apparently not too exacting. The PGL rise or fall vs. the cross slope of the structure...and of course the CL of rdwy. is not the CL of the Bridge. There has to be an Excel spreadsheet or program where data is input and the relationships between the angles and distances are expressed more easily. I hope I have made this clear as mud.

 

[graybeach]

Drumchaser,
You should make your own spread sheet so are you crystal clear about what you are doing. Here are some hints from one I did for a bunch of curved skewed bridges:
-input your vertical curve and cross slope info in a table with each different segment labeled with a number.
-input the TGL station and offset of each bearing point.
-use nested if statements to identify the corresponding vert curve/cross slope segment
-use VLookup to extract the info needed to calculate your top of deck el over each bearing.
-subtract the structure depth

 

[crossframe]

I agree with graybeach. I made my own spreadsheet 8-10 years ago. I now have several different versions to handle metric, two-spans, etc., and have expanded it out to include blocking distances, haunch depth, shear stud heights, and wingwall and approach slab elevations in addition to beam seat elevations. I have even used it during construction to check as-built conditions. I also use it an "independent check" of our Geomath runs.

The best thing is... I know what every single cell does.

 

[twopie56]

Drum Chaser,

If your looking for a sofware that can do all the Geometry
of a Bridge Try Geopak since you mention Microstation.

Although you have to learned to used it first, This one is worth your time to learn because you desire automatic and
precise calculation....

Any kind of Bridge is peanuts with this Software....

 

[Drumchaser]

Good comments.....thanks. I do not have access to Geopac. Think I'll just trudge along with my HP.