## Combining Local Flange Bending with Longitudinal Bending

## Combining Local Flange Bending with Longitudinal Bending

(OP)

Hello, I am designing an underhung crane that we will use on a bridge project. the runway beams will be attached to the floorbeams that run transverse to the roadway with Lindaptor Clamps. I am using CMAA 74, AISC dg 7, AISE rpt 13, and a few others along with osha. my question is combining the longitudinal bending stresses (fbx,fby,fb torsion) with the local flange bending generated by the lindaptor clamps clamping onto the runway beams. In the past I have used sqrt(sum of squares) in different applications. This approach seems like an average of the von Mises method, with shear almost dropping out. with von Mises, the +/- (fbx)*(fby) value adds or subracts depending on which side of the flange you are evaluating. Any thoughts? i am thinking the sum of squares method is acceptable.

i have attached a page from a Lindaptor data sheet that shows how these clamps can be used.

Thanks.

i have attached a page from a Lindaptor data sheet that shows how these clamps can be used.

Thanks.

## RE: Combining Local Flange Bending with Longitudinal Bending

CMAA 74 has a very detailed calculation for evaluating these effects. Be careful to watch your signs since normally these calcs are combining the tensile bending stress with the local bending stress from the wheel load. In your case you'll likely have compressive bending stress since your clamps are on the top flange.

Our friend Alex Tomanovich at STEELTOOLS.ORG has developed a pretty nice spreadsheet that will do most of your leg work. I have never checked his spreadsheet but it gives identical results to a spreadsheet I developed for the same purpose.

Go to www.steeltools.org and search "Monorail"

## RE: Combining Local Flange Bending with Longitudinal Bending

## RE: Combining Local Flange Bending with Longitudinal Bending

So, The crane girders have the clamps connecting their top flanges to the bottom flanges of the bridge deck girders. Then the bottom flanges of the crane girders support the wheel loads from the under hung crane/trolley.

Essentially there are loads on the top and bottom flanges on the crane girders.

## RE: Combining Local Flange Bending with Longitudinal Bending

## RE: Combining Local Flange Bending with Longitudinal Bending

Again, I don't think you need to go Von Mises on this (not that you can't or shouldn't).

The calc laid out in CMAA 74 covers all the stresses you are concerned with in pretty good detail.

It incorporates the major axis beam bending stress, shears, and the local bending effects from the wheel loads or clamps.

The difference I am noting is that the major axis beam bending stress on the top flange will be compressive, the top flange local bending will also be compressive on the top surface of the top flange. Normally the calc is for the bottom flange where the major axis beam bending stress is tensile so you'll have to watch your signs.

## RE: Combining Local Flange Bending with Longitudinal Bending

## RE: Combining Local Flange Bending with Longitudinal Bending

## RE: Combining Local Flange Bending with Longitudinal Bending

## RE: Combining Local Flange Bending with Longitudinal Bending

## RE: Combining Local Flange Bending with Longitudinal Bending