Snow Loads as Dead Load
I have applied a snow load to the perimeter of my building where I will have a drift that goes from a 19.3psf snow load at the edge to a 77psf load at a wall 6ft in.
When I look at the line loads on the perimeter W16x26, I am seeing the snow load…
Understanding Drift Results
Hello, I am trying to understand drift results for my structure using RAM SS. We have semi-rigid diaphragms modeled and are trying to use the drift at control points to check the drift ratios. We have chosen select frame nodes coordinates as our control…
Modelling a drift from an underground mine in PLAXIS 2D
Application
PLAXIS 2D
Version
PLAXIS 2D 2023.1
Date created
10 March 2023
Date modified
10 March 2023
This movie shows how to set up a model in PLAXIS 2D starting from a drift cross section of an underground…
Seismic and Wind Drift Calculations
When analyzing a structure in RAM Frame, do the drift results calculated use the ultimate or the service wind load? Also in RAM Frame, do the seismic drift results calculated use an elastic analysis or is the design ratio calculated by multiplying by…
Staad.PRO - Imperfection analysis
Hi! I have some doubts about how does Staad consider the inicial imperfections.
I have a structure that has been exposed to fire. Its mechanical properties have not been altered but there are elements that are visibly deflected.
I want to study…
RAM Frame Total Displacement & Story Drifts Output
I am running into a weird output from Ram Structural System's, RAM Frame module regarding total displacement/drift.
From my understanding, the Total Displacement at the roof level should equal the sum of the displacements of both the roof and second…
RAM Frame - Story Drift at Control Points
Applies to
Product:
RAM Frame
Version(s):
Any
Area:
Results
Values for the report.
Displacement: Total displacement at that coordinate
Story Drift: Displacement relative to the floor below.
Drift ratio: (Story…
Perform Imperfection Analysis - Drift - Syntax Error
Hello,
I am trying to perform an imperfection analysis on a simple two-storey frame structure. Imperfection is of DRIFT type applied to columns.
Whenever I leave the text editor it prompts a syntax error on the "perform imperfection analysis" command…
Lateral displacemente of semirigid diaphragm
Hi,
I'm trying to verify the drift of a one-story ware house with tilt-up concrete panels and steel deck roof.
I followed all the information that I found on the forum, but I still have a few questions:
First I calculated the properties and displacement…
Drift correction for dynamic input signal from file
Application
PLAXIS 2D PLAXIS 3D
Version
PLAXIS 2D PLAXIS 3D
Date created
23 July 2014
Date modified
23 July 2014
Due to integration of the accelerations and velocities, a drift might occur in the displacements. When…
Drift
What is the best way to look at building drift when your floor plan changes up the building? I am looking for the drift between floors but my building floor area steps in above L2 through to the Roof, but the facade is sloped and reaches out from the…
Displacement vs. Drift
I have done a building, and I need to design expansion joints around some CMU shafts to avoid loading them. When I do the Results - Drift sheet, I see I am given displacements and drifts. When I am designing this expansion joint, which number do I take…
drift check
hi guys I am new in staad,
I made a simple 2 storey residential house, its members should be in simple sizes/dimensions but my model is not passing in drift check using simple dimension of members. any suggestions what should I adjust ?
here is my…
RE: STADD.Pro V8i - Direct Analysis Method AISC 350-05 / 10
The purpose of DIRECT ANALYSIS is to compute the member forces for strength design. For computing drifts, deflections you should use a PDELTA 15 ANALYSIS with the un-reduced stiffness and not a DIRECT ANALYSIS. Both analysis commands could be part of…
ST_EXFORCE command report drift forces which do not look correct
Q: Why does the ST_EXFORCE command report drift forces which do not look correct? REV 5.08
A: What you are getting with ST_EXFORCE is not wave drift, but first order wave excitation. You can look at wave drift raos in the Hydrodynamics Menu with V_MDRIFT…
"Wave Drift" forces look strange
Q: Why do my "Wave Drift" forces look strange? REV 7.05
A: You do not have a good panel model for diffraction. Remember, the drift force depends on the gradient of the velocity potential while the first order forces depend only on the potential. Thus…
Checking Story Drift of Floors
Applies To
Product(s):
STAAD.Pro
Version(s):
All
Environment:
N/A
Area:
Design
Subarea:
American Steel Design
Original Author:
Bentley Technical Support Group
…
RE: RAM Frame Drift Control Module: Question about Virtual Loads and Load Pairs
I have only used virtual load cases with lateral force on a single diaphragm. The program allows you to enter other loads, but I've never had a good reason to do so.
I ran a simple test here and I don't think the scale for the load pair actually does…
RE: STORY DRIFT
Let me explain this with some values.
To get the Allowable drift to be L/40, you must have input the following command
PRINT STORY DRIFT 0.025
The drift factor (without the correction for Cd/I) which you picked up from the table, is 0.025. Now let…
Story drift check in STAAD.Pro as per ASCE7
Applies To
Product(s):
STAAD.Pro
Version(s):
ALL
Environment:
ALL
Area:
Modeling
Subarea:
Seismic Load generation
Original Author:
Sye Chakraborty, Bentley Technical…
RE: Master Slave command
The nodal displacements that you see in the postprocessing tables represent the total displacements of these nodes from its original position. For drift computation you would rather want to know the relative displacement of a floor with respect to the…
RE: Drift ratio in RAM Structural System - Story offsets/multiple stories?
The program checks the same plan location for each story and identifies if there is a diaphragm at the adjacent story or not before calculating the story displacement in the drift report. I also like to double check this using nodal displacements when…
RE: Story Drift Results Interpretation
I'm not sure what program you are using or what kind of output, so I'll try to answer in general terms.
For any finite element analysis application that uses a rigid diaphragm assumption, the horizontal displacement of the diaphragm can be given at…
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Re: STORY DRIFT
The easiest would possibly be to use the IMR command in your spectrum case. Here is an example
LOAD 4 LOADTYPE None TITLE LOAD CASE 4 SELFWEIGHT Y 1 SELFWEIGHT X 1 SELFWEIGHT Z 1 SPECTRUM SRSS IBC 2006 X 1 ACC DAMP 0.05 LIN IMR 10 STARTCASE 101 ZIP…