|
SW Ohio | Ken I am no engineer but Dad was. Our bridge spans 30' with the beams 32', we redid it the 80's with used 14" x 32#???, six beams for 16' width, 3x4 lumber on top 16' long. Turned out the beams came from a burnt building and were not perfectly straight, this led to the boards flexing with each other on every pass of a truck, put a 1/4" steel plate over the center 8' but after many years the boards kinda disintegrated. We (without Dad, he was gone) redid it again a few years back, bought four new 14W36 beams ( a little more than the old ones that dad said were twice what was really needed) and regular treated 4x4's, added a full steel plate over that just for overkill. The bent beams never failed but were rusting badly in places, had no cross connections except one 2x2 angle in center span at the bottom, this model had one load over it that grossed 130,000 on a 40' tandem flatbed (don't ask). This whole project replaced the bridge that I grew up with, it was 32x 14 with only four 10" by not very heavy beams in the middle and 10" C channels on the sides, covered with 3x10's and a three inch layer of blacktop on top of that. We would ship out maybe a couple semi loads a year but the tandem milk truck went over it every other day. When the webs of those 10" beams had light showing through them was when we decided to replace the whole thing, it never failed but was getting scary.
short version, you really need an engineer to calculate the sizes, it is not something found in a table. That said it sounds like your old ones were big enough, just replace with similar ( and throw some cheap paint on them!) | |
|
Where to find a steel bridge beam load chart?
