Soft Story Check In Staad Pro
Claudio Davey
In an expression of "PRINT MAXFORCE ENVELOPE LIST 1 2 3", after manual correction of source file, STAAD deletes "LIST" before a list of members and after reports that it's arbitrary change as an error. This annoying bug exists for a while. When I can expect for an improvements?
when we intersect two beams which cross eachother , it is obvious that one beam would support the other one. bcoz in real life usually the longer beam rests over the shorter one when they intersect eachother bcoz the shorter one is more stable. So how do we make sure which beam of the two would rest over the other one when they intersect in staad.
I looked further into this and it is the combined effect of the following that is causing the extreme soft story. Absence of a floor diaphragm at 10 ft level. Increased floor to floor height of that floor ( 12 ft as opposed to 10 ft for the other floors ). Supports being PINNED as opposed to being FIXED. If you make all of these changes, the extreme soft story warning would be gone. If you cannot make these changes, you will have to look for other options to make the lower floors stiffer. Adding braces, higher column/beam sections at these floors, adding shear walls are some of the options to consider.
I need a solution to avoid soft story in my model. And without load change, how many ways it can be solved? Please, give me a brief explanation so that I can keep it economical but safe enough. I dont want to add shear-wall if possible. Below I attached my model and mentioned a brief information about my model:
There are 119 disconnected structures in your model. You can find these out by going to Tools > Check Multiple Structures. As a quick fix, I selected all the members and went to Geometry > Intersect Selected Members > Intersect to make these members intersect.
You may want to take a look at the following wiki for more details on connectivity issues
communities.bentley.com/.../269581
Also the members 77 237 1057 were missing property assignments. Based on the properties assigned to the adjoining members, I assigned properties to those. The modified file now analyzes without errors and is attached for your reference.
Good day, Sir/Mam. I seem to have a problem with my staad results and i can't seem to locate where the error occurs. Can u please check what seems to be the problem to my output attached below? Thank you so much!
I confirm that the issue is not there in SS6 ( version I used is 20.07.11.82). I even checked with SS5 version ( 20.07.10.66) and that did not have the issue either. I tried making changes to the section properties using the editor ( model attached ) and the LIST in the MAXFORCE command was retained in each case. So this definitely seems like an issue with SS4 but SS5 or SS6 should not have the problem.
The analysis output file would print the Center of Mass for each diaphragm whenever the floor diaphragm is used. So you do not need to add PRINT CG for that. The center of mass calculation would account for all the masses at that level designed using the Mass type reference load. Also PRINT DIA CR would print the center of rigidity for each diaphragm in the analysis output file.
This document provides a checklist for analyzing a structural model in STAAD:1. Check model dimensions, storey heights, material properties, member specifications, loads, and meshing before analysis. 2. After analysis, check for equilibrium, excessive deflections, and ensure member forces are acceptable. 3. Additional checks include torsional irregularity, ensuring walls take 75% of base shear, checking for soft storeys, and ensuring base shear scaling matches code. Having only walls may result in a very stiff building model.Read less
Check soft story command checks for plan and vertical irregularities in a building viz. a floor whose lateral stiffness is less than% of the floor above it or less than% of3 floors above it is called a soft story.
The warning shown for soft story with respect to floor levels not being defined is because individual floor heights should be defined before using the Define command or any primary response spectrum load case. If floor heights are not user defined, staad usually considers/identifies floor levels in order of increasing magnitude of Y-coordinate joints, however, this is true only in case of buildings with well defined floors (i.e. it does not contain shear walls, staggered floors etc.). Hence user defined floor heights become necessary for soft story check.
I'm trying to get an understanding of a weight discrepancy between my results in STAAD.Pro and my results in STAAD.Offshore. When I run a simple gravity case for a structure in STAAD.Pro, I get a resultant weight as a sum of the y-reactions at my supports.
Comparatively, when I take the same structure with the same supports in STAAD.Offshore, and run an transportation case setting only the heave acceleration at -1g, the resultant sum of the Y direction forces equates to approximately 1.06 times the resultant weight of the STAAD.Pro model. This has been tested with multiple structures and on multiple computers, so from what I can tell, there may be an issue with the software.
Has anyone else come across this issue? As this will affect the results in all other transportation cases that will be run, I was hoping to sort this out and align the weights prior to finalizing my analysis. I would appreciate any information that anyone could provide on the above.
Will STADD do this for a sinle column without any external horizontal loads? does my column need to part of a frame system. The column is modeled as beam elements and the axial load is set to be a repeating load, however when i run the analysis, with 30 iterations, I only get displacements in the Y direction. I would expect at some point the column start to buckle under the axial load. I even applied an axial load that far exceeds the column capacity.
Actually I was given with an architectural plan with column positions fixed and in no situation I can avoid a column to be eccentric. I have came across a problem on how to model a column with its beam connecting both ends in eccentric manner. I have attached a snap shot of it in order to give a clear idea. Please suggest me on how should I proceed towards my solution and it will be of great help if someone can model a small case in STAAD keeping the above problem in mind.
The wind load generator contains a factor, f to be used to multiply wind loads with a default value of 1.0. Is this factor where the user might adjust the wind load for varying shape factors for open structures as given in ASCE 7?
In parallel to this post, I have submitted a question to the ASCE 7 Wind Committee asking for clarification on how to apply the calculated value of wind force on a lattice structure given in the standard. Currently, the wording in the standard implies that the wind load is for the vertical panel on the leading face of a square lattice tower. This would require applying the wind force to the windward and leeward faces of the tower.
And the answer I got is, Check whether the DJ1 and DJ2 commands in your file are ahead of the deflection check commands (DFF) or not. Else the software may calculate the allowable deflection based on the length of the analytical segment as opposed to the physical member specified through DJ1 and DJ2.
Though the results will be available for every analytical members which are part of physical member in output file but Deflection Check will be performed using the full length of the physical member defined by DJ1 and DJ2.
I have a main beam with splice joint as shown below. how I tell staad there is a welded splice connection?. How I will get the moment diagram and report of that particular joint. and what will be the effect of load on the splice during lifting of the frame. Hope someone can help me.
Could you help me on this. I am using Limcon haunched connection. I need to check a as built connection where fabricator used different edge distance for top & Bottom flanges. I can't make it to take different edge distance in Limcon model.
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