Two HSS members are to be spliced and there’s a moment of at the connection.
How to do this. Please guide.
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HSS Splice Connection
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Base plate design - using support reaction or beam end force
Hi, everyone.
I encountered a doubt while I am designing Base plate of Steel column.
The question is which output should I use for my base plate of Steel column.
Which one is normally recommended when designing Piperacks or Equipment supporting steel structures ?
- Situation1) Using Beam end force of the steel column with modeling of concrete pedestal or
- Situation2) Using Support reaction of the steel column without modeling of concrete pedestal.
Situation 1)
- Structural steel frame and concrete pedestals are modeled.
- Support conditions are given to the bottom node of concrete pedestal
- Bottom node of steel column has beam end release condition according to the structural configuration and anchor bolt arrangement
- Then, I get beam end forces of the steel columns and can use them for designing of base plates.
- And, additionally, support reactions are used for designing concrete foundations
Situation 1)
- Only Structural steel frame are modeled. (concrete pedestals are not.)
- Support conditions are given to the bottom node of Steel columns according to the structural configuration and anchor bolt arrangement
- Then, I get support reaction at the bottom side of the steel columns and can use them for designing of base plates.
- And, in this time, duplicated and modified model with concrete pedestal is required to get output for concrete pedestal and foundation design.
I am waiting for your opinion.
Thank you!
YJ Kim
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Doubts in first time plate modelling in STAAD
Friends,
Finally the time has come to bite the bullet and I have to do PLATE modelling for the first time in STAAD.
And as expected I have run into problems.
The thing is I have created two STAAD files of the same model, one with quardilateral meshing and the another with polygonal meshing, and I am getting huge differences in the plate stress levels. This is what is leaving me confused. I have attached the STAAD editor file for your reference (Website is not allowing me to upload .std files). Please copy paste the text into your STAAD editor to generate the model.
Although I have practically no background in plate theory and modelling, but I have followed the aspect ratio for individual plate elements as far as possible in quardilateral plate meshing. Also I am under the impression that more the meshing you do, more accurate the results.
The static check results are same (almost) in both the models, the reaction forces are quite similar in both the models. But there is an almost 10 times the difference in plate stress results.
I am checking Max Von Mises stresses in Plate results section in STAAD.
Also one more seperate question. If the plate stresses are ok, can we assume that no buckling will occur in the section?
Am I interpreting the results correctly?
Regards,
Debayan
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STAAD inclined support question
I used inclined support for a curved bridge and got a warning *WARNING* INCLINED SUPPORTS IN A DYNAMIC RESPONSE ANALYSIS. PARTICIPATION FACTORS ARE APPROXIMATE. MASS DIRECTION TRANSFORMATION IS AS IF FORCES. Can anybody tell me what does it indicate? Appreciate it.
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Instantaneous Deflection with cracked sections
Hi,
I was wondering if RAM Concept outputs instantaneous deflections with cracked sections? I was thinking of using the load history deflection calc. But only having the load applied for a day or two to bypass any creep. Also is two days too long or too short? Does the cracking occur as long as the load is greater than the cracking moment or does the load need be applied a few days to get it to crack? Any help would be appreciated?
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RAM Concept: Slab classification of prestressed slabs
My capacity for my two way pt slab is 7.5 x f'c^.5. I'm thinking it should be 6xf'c. Not sure how to correct this.
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Staad Select Series 5 release
Dear Sir,
On the RSS feed, I am getting message of the release of Select Series 5 of Staad Pro v8i from yesterday, but I am unable to see download link for the same in SelectServices site. Please clarify.
Also, when going through the revision list, I noted the following: In point A 35, it is noted the addition of flag MFace to IS456 design parameters to match SFace and EFace. Please note that Critical Moment is typically taken at the face of the support whereas Critical Shear is typically taken at a distance d (effective depth of beam) away from face of the support (see clauses under 22.6 of IS456 2000, specifically 26.2.1 and Figure 2a, 2b). Hence, in my humble opinion, it is better to set two parameters similar to SFace and EFace for moment instead of using a single flag as noted in this.
Thanks in advance
Yours sincerely
S Arunkumar
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Curved Beam in STAAD PRO !!!!!
Can we design curved beam in staad pro v8i ?? i tested a 2D FRAME consisted of 2 columns and 1 curved beam , the 2 columns have been designed for reinforcement steel but the curved beam has not been designed . ??? please see attached file
http://www.gulfup.com/?ahXDdW
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STAAD joint instability warnings and errors
I'm modeling a curved steel gieder bridge. The pier cap is a little wider (only 0.2 ft) than the deck so very small beam elements are added as highlight in the attachment. The end nodes of pier caps are not connected to any other nodes. The nodes next to the end nodes are master nodes and the nodes right above them are the slave nodes. After i ran the model, it showed warnings and errors about the instability in terms of FX FZ MY MZ of the end nodes as shown in the second attachment. Strange thing is, the instability only occured at nodes on one side (the longer edge) of the bridge. And I tryied to set the end nodes as the slave nodes to the other end of the beam elements ( nodes next to the end nodes), to make it rigidly connected, so the intability would be gone. However, it turned out the instability somehow transfered to the other end. I know I could delete those small elements so the instability problem will be solved, but I'm curious why this happened?
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section wizard and user table
I have created a compound section from section wizard. I export it to staad but its not coming up. how can I add the compound section created in section wizard to user table?
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STAAD.Pro V8i Apply Vertical Load as Lateral
Hello,
I would like to know if there is a command other than notional load in which I can take a vertical load and apply it laterally? For example say I have:
LOAD 1 DEAD LOAD OF STRUCTURE (D)
and in the Seismic load case I would like to take all the vertical (-Y) loads I've defined in LOAD 1 and orient them in a lateral (+X, +Z) direction.
I am aware the NOTIONAL LOAD command does this, however any uniform load that was defined in the referenced load case is applied as a joint load, therefore member design is not performed when using the NOTIONAL LOAD command with uniform loads.
The reason I ask is because I'm trying to find a way to streamline entering in my seismic loads. If there was a command that applied a previously defined load case (DEAD LOAD) in the direction specified (in my case +X, +Z) then any time I changed something in the previously defined (DEAD LOAD) case it would automatically be updated in the seismic case. I have worked my load combinations so no factor needs to be applied in the LOAD CASE, the combination takes care of the factor adjusting the dead load to its appropriate seismic (lateral) force.
Any input would be appreciated. Thanks in advance for your help.
Brad
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Floor Vibration Analysis
Hello. I am currently using the beam module in RAM Structural System to perform a floor vibration analysis for a steel frame building with exterior masonry walls. I understand that RAM is linked to Floorvibe to perform the analysis and that it categorizes the bays into perfect, imperfect, and irregular bays. I currently have imperfect bays and my question is whether RAM Structural System or other RAM products can analyze a imperfect bay as it is configured rather than idealizing it as a perfect bay.
For example, a perfect bay has 4 columns at each corner. I have a condition where 1 of the columns is offset such that a beam cantilevers over the column to support the girder. Is there a way to analyze this configuration without idealizing it? If idealizing the bay is the only way, how will the results for the idealized bay compare to the actual conditions?
Thanks.
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Applying tangential pressure on plates
I am designing a bottom ash hopper. They want to model the hopper as plate elements and apply normal as well as tangential pressures on plates due to stored ash. i have calculated the pressure at different depths and have applied the normal pressures. Can anybody tell me how to apply tangential pressures on plate elements.
Regards
Rajarshi Bose
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Machine foundations
Hi,
I am wondering if some one could post some tutorials, technical papers, Staad files, etc on design and analysis of machine foundations including dynamic aspects. I would like to use both StaadPro (advanced) and Staad foundations (advanced) to design these structures.
Thanks.
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Clarification about the Input Parameters
In a truss design, Which input parameters is most important for IS:800
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Clarify
In Staad Pro, I do Modeling , Assigning Loads , supports, & Member Property . In Design i will select steel design IS:800 and assign, Check code and Steel Take off only. Do not assign design Input Parameters to Run the Analysis. The Output Result will be behave correct or not
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Allowable stresses
How to apply Allowable stress in staad pro
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How to apply these input parameters give some examples
DFF, Dj1, Dj2, DMAX, DMIN, KY, KZ, LY, LZ, RATIO, UNF, UNL TRACK
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Seismic Parameters Scroll Bar
Question:
In the new colombian seismic code 2010 I can't see the input values in fields dialog including moving the scroll bar:
Answer:
To make the slider active, please hover the mouse pointer over the line separator between Parameter and Value columns, press and hold the mouse button to drag the separator line to the left and the scroll bar will become active:
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Completing Seismic Analysis
Hi,
I am trying to complete the combined seismic and static analysis and wondering if someone could clarify the confusions I am facing!!
I have attached the model which runs fine for the static cases. Now I am also trying to complete the seismic analysis so I could combined the static and seismic actions to get the worst forces. The seismic parameter I am available being zone 2A as per UBC 97.
While refering to example say (BS example No.11) and performa available when specifying the seismic specification there are following complications.
Issue 1: I would like to use the loads defined under static load cases (i.e. 100% of self-weight and dead loads while 25% of live loads) but in the spec performa it asks me me to redefine loads like self weight , joint weights etc (without a way to apply to specific locations and members)... I am not use how to use this?! I would like to use aready applied forces with base response spectra applied?!!
Issue 2: While response spectrum template, 'generate' button for UBC97 response spectrum is not available?!
Issue 3: Within the loads items list there are two cases available 1. Seismic loads and 2. Response spectra, which one to use in conjunction with seismic parameters already defined?!
Please could someone advise how to go about completing the analysis!!
Thanks.
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