Recent content by koo

guys, got a pricing question about additional charge if I am asked to stamp the calculation and drawings for connection design. I didn't stamp them before and only submit calcs. for others to stamping (EOR). Now they want me to stamp it. What price diff. does it make on an hourly rate basis...

looking for a AISC based connection design program, better have dimmension and calc. sheet output. Which one is most commonly used?

VOD, That's what I thought first, but after checked my models and have Staad, Sap tech supports checked them. I couldn't find any problem with them. But I am not sure Ed's end release method is correct in modeling a composite section. (there should be large axial load since NA of the section is...

Ed, I tried MPZ, MPY, but no effect. Then I used MZ, MY, indeed, the links become a connection rod taking only compression. But the total moments at beam and slab still didn't add up to AASHTO value. I think by using MPZ or MP, the deck and girder effectively become non-composite, right? The...

ed, 1. Can you clarify if it's MPZ or FPZ? Your two posts gave them differently. Are you sure it's correct command? Member release has FX(full release), KFX(spring) and MP(partial), which one are you trying to tell me? Partial momement release in Z? 2. Is 0.999 an arbitrary number? how did...

ed1, glad you are here. I was looking for you. I modeled a simple steel composite bridge in both Staad and SAP with the method you described before( plate for deck, frame for beam and bolster). The results are good at supports, but midspan bending moment is much less than AASHTO values from...

Qshake, Thanks, looks like a good book. Can you check my question for you in the lateral bearing load thread? Thanks. Koo

All, I am looking for good books on cable stayed, suspension, and arch bridge design/construction. Can you guys recommend some? Seems few out there and many out of print. Thanks, Koo

Structuresguy and lippie, Thanks for your input. Let's get back to the technical...I had a long talk with Staad. What I understand from it is that the axial force is due to the bending of the composite section (tensile on bottom, comp on top), however, the section modeled in Staad is not...

I modeled the beam as a frame member. He said the axial is actually tension. The moving load is generated by a string of static loads with a increment between. I don't see a horizontal component though it's possible after the deck deflects, I think. The support guy I talked to is very...

Structuresguy, Yes, I tried to release axial moment at one end, still not much change. Staad support offered me the explanation that the lateral reactions may come from diff. deflection of slab (but the net lateral force by summing all supports gives 0), and the axial force in beam is actually...

I modeled a simple composite steel bridge in Staadpro 2002. Deck is modeled as plates, girders as frames, bolster as frames. HS20 moving load. But the oupput gave me large axial Fx load in girders and lateral reactions at supports (pinned), even larger than vertical reactions! Where could...

VOD, I specified trans. member to be concrete and gave it a demension (9" by 9.5'). Isn't J a property of the section and generated automatically by Staad based on my input geometry? I found nowhere I can edit this property. You also mentioned earlier that "the torsional properties of the...

VOD, sorry that I still need to ask you several questions about grillage modeling. I started building a simple steel bridge in StaadPro. It has 4 beams at 9.67' spacing and 38 feet span, 2lanes for HS20 truck. I put 3 transverse frame members with concrete deck properties (9.5'...

VOD, My model is based on a straight bridge though. It's the simplest form of a composite steel bridge. So I'm quite supprised with the results. I can't find anything I did wrong in the model. I don't know how sap or other programs move its self-generated AASHTO load, only along the bridge...