Hi all, I'm looking at an old bridge pier foundation, with a pile cap supported on H-piles. The piles go mostly through sand and are tipped in shale. On the structural capacity side, using allowable stress design, the AASHTO Std. Specs (which I'm less familiar with compared to the LRFD) limit...
Hi all,
I just had a general question about the calculation of the AREMA rocking component of impact in beam spans, particularly as shown in an example of John Unsworth's "Design and Construction of Modern Steel Railway Bridges." As shown in the attachment (hopefully), the cross-section in...
In the final condition of the bridge with piers in water where they've performed cofferdam construction, would you typically assume that your piles are carrying the weight of the tremie seal ? My tendency would be to conservatively assume the weight of the tremie seal can be transferred...
I’m looking at designing anchor rods at a fixed pier of a 3 span continuous bridge (E-F-E-E) to meet AASHTO 3.10.9.2 requirements of the horizontal design connection force of 25% of the vertical reaction due to tributary permanent load and live load assumed to exist during an earthquake...
This is the first project I've worked on with a non-unity factor (eta=1.05/0.95) where I've also been tasked with designing joints and bearings. I think the answer is yes, but thought I'd get some confirmation -- do the eta factors apply to deformations/movement ranges?
Thanks!
Hi all, I'm struggling to find guidance relating to typical assumptions made for thermal force and movement calculations and was hoping to find some references or thoughts/reassurances as they relate to:
1. Design displacements for bearings
2. Design displacements for joints
3...
Suppose you have a steel box sitting on a steel plate with a force applied at the top perpendicular to the box. The box is heavy enough that the load doesn't cause overturning and the friction force is large enough to prevent sliding.
Now suppose you fillet weld the sides of that box to the...
Hey guys, I had a question about laying out design trucks for DF calculations using the lever rule. The attached picture comes from Barker and Puckett's Design of Highway Bridges, an LRFD Approach. I just wanted to verify that what they are showing violates AASHTO's 2' minimum from the design...
Hello,
I'm designing a bridge connection that ties a concrete deck to a steel arch below it at the crown (preliminary phase of a project). I plan to embed a steel plate in the underside of the deck, anchored by shear studs (7/8" dia.). The stud plate will be welded to a vertical plate...
Salmon and Johnson seem to do a pretty good job, but I was wondering if there were any other references you've found useful (papers, books, manuals). I'm an EIT with little background in designing connections and would like to become more competent.
Thanks.
I'm sure these will be trivial to many of you, but...
1. Will buckling occur in slender columns (steel is probably easier to think about for me as an example, but I guess infinitely well confined concrete or something may work too) even if the column itself is ideal (no imperfections, is plumb...
For a structure that I believe to have passed its stability point (based on load-deflection behavior that has passed a point with zero tangential stiffness/went through a maximum) can anyone confirm that at that I should be able to verify the stability point has been reached using energy output...
Hello everyone,
I'll be finishing my M.S. in Structural Engineering this semester and preparing to join the workforce when that time comes. Obviously the job market is pretty tough right now with limited new design (although from my perspective the bridge design market and forensics...
Hello,
I have a quick question regarding live load reductions for columns. The question is similar to the one found here:
http://www.eng-tips.com/viewthread.cfm?qid=142628
but I'm not sure I understand what JAE says and I just want to make sure I'm applying this correctly. For a typical...
Hello, I'm new to FEA/FEM and was wondering if anyone has encountered the following problem with mesh density sensitivity before:
For some background, I'm using ABAQUS to model seismic isolation bearings to determine stability/critical behavior at various displacement levels.
Anyway, I've...
Does anyone here have experience designing elastomeric seismic isolation bearings with bolted connections (or doweled) I guess? If so, I was wondering how you go about checking stability at design/maximum displacement levels. For doweled connections you have rollover to consider as well, but I...
