Re: No consideration of the piers, abutments and foundations! Re: Lobato Trestle Report

Chris,
You say that the engineers "ignored the dynamic loading." But in the HDR, it says that Hammering Effect was ignored, but Rocking Effect of engine, tender and train are included in the analysis. So isn't that rocking motion a dynamic load?

Could it be that the hammering effect isn't very large since the bridge is nearly level (engine not working hard) and the train is moving slowly? Seems to me that the hammering load (vertical motion) is balanced on the bridge, where as the rocking motion is much more asymetrical (loading one side while unloading the other). Am I missing something?

Phil

Chris Webster Wrote:
-------------------------------------------------------

> The "superstructure" are the spans between piers.
> HDR did a structural analysis of these spans and,
> even though HDR ignored the dynamic loading from
> the locomotive drivers and cars, the spans still
> failed the analysis.
>

Quote:
HDR
During the field inspection the General Manager Marvin Casias of the Cumbres & Toltec said that the trains coast over the bridge at a speed of 8 mph because the bridge sits in a sag vertical curve. HDR utilized this information and did not include the impact due to the hammer blow of the engine in the rating analysis. Impact due to the rocking effect of the engine, tender and eight (8) viewing cars was included in the load rating analysis.