Ajay Datta's Communities Activities

Response modification factor, over strength factor and deflection amplification factor

Ajay Datta — Wed, 17 Apr 2019 07:31:06 GMT

In this connection I have seen the following reply

Seth Guthrie 6 months ago in reply

Yes, You can manually enter a combination with some extra factor like Cd to get amplified values, but I honestly find it faster to just factor the deflection results manually or factor the limit instead.

I have some confusion and request clarification regarding use of Response modification factor (R) , Overstrength factor(Ω₀) and Deflection amplification factor (Cd)

In Staad GUI input for seismic load definition I get the opportunity to give Response modification factor Rx and Rz .

While preparing load combination for Strength design I get the opportunity to use over strength factor (Ω₀) as shown below

Next about Cd two questions?

I suppose this deflection amplification factor(Cd) is to be used in in conjunction with Serviceability design? Is this required required to be considered for strength design as well?

How to use this Cd as in the seismic definition input as there was no scope to input.

Basic Combination for Strength design with seismic load (ASCE-7-2005)

(1.2+0.2Sds) D+Ω₀Qe+L+0.2S
(0.9-.2Sds) D+ Ω₀Qe+1.6H

Hope someone will clarify

WARNING SELF WEIGHT ... MORE THAN TOTAL WEIGHT

Ajay Datta — Sat, 30 Mar 2019 13:19:10 GMT

I get the following warning in my analysis. Staad file attachedcommunities.bentley.com/.../RVISED-BY-AJAY_2D00_-2FRAME.std

*WARNING- APPLIED SELFWEIGHT IS MORE THAN TOTAL WEIGHT OF ALL

STRUCTURAL ELEMENTS IN LOAD CASE 105 ALONG Y.

THIS COULD BE DUE TO SELFWEIGHT APPLIED TO SPECIFIC

LIST OF MEMBERS/PLATES/SOLIDS/SURFACES.

TOTAL UNFACTORED WEIGHT OF THE STRUCTURE = 822.911 KN

TOTAL UNFACTORED WEIGHT OF THE STRUCTURE APPLIED = 1645.822 KN

Reference load-Seismic-definition-Seeismic-load

Ajay Datta — Wed, 03 Apr 2019 08:15:32 GMT

Dear Sir;

I already posted in forum but my problem did not get resolved.

1.First I have used Reference loads

2.Then created seismic definition using reference load

3. Then generated automatically seismic load using seismic definition.

4. Now I want to combine different loads with seismic load for direct analysis.

But get some error which means “cannot combine reference load with primary loads”

How do I combine seismic load with other loads in such situation. Please advise

Thanks

Ajay

Deflection Amplification Factor Cd

Ajay Datta — Sat, 27 Jul 2019 11:25:58 GMT

As per ASCE 7 deflection amplification factor Cd=3 to be use for my structure which is cantilever car park.

My question is do I have to multiply both vertical as well horizontal deflection due to seismic load by Cd value to check the serviceabilty condition.of vertical deflection of span/180 at the cantilever end?

Or this amplification factor is to be applied for the horizontal deflection(DRIFT)?

Please can someone clarify?

line too long error message

Ajay Datta — Tue, 25 Jun 2019 07:03:05 GMT

I have a large load combinations which takes more than one hour in my computer system. Unfortunately after one hour I get a error message "one or more lines too long-try to split into two lines"

Can we not get this simple editor check message within few seconds of the run so that we can correct the same without wasting our time. Please advise

Post processing Results setup

Ajay Datta — Wed, 03 Jul 2019 11:33:31 GMT

I am trying to use the Results Setup for checking the Utilisation Ratio of various GROUP of members for optimisation. However only once I get to see the Result setup window after I click Postprocessing.

Second time this window does not appear . Can you help me so that I can repeatedly see the Result Setup window in the same postprocessing.communities.bentley.com/.../REVISED-MODEL-SIX-FRAMES-6M-BAY-SERVICEABILTY-_28002B00_X-NOTIONAL-LOAD_2900_--2M-PORTAL-DEPTH-12-JUNE.std

NUMBER OF LOADS IN A LOAD ENVELOPE

Ajay Datta — Fri, 07 Jun 2019 06:18:14 GMT

I HAVE A PROBLEM WHERE THE NUMBER OF REPEATED LOADS ARE MORE THAN 600

WHEN RUN STRENGTH ANALYSIS I GET THE ERROR AT THE END "LOADS MORE THAN 555 NOT ALLOWED IN LOAD ENVELOPE"

SO I PUT LOAD LIST 2001 TO 2688 AND RUN FOR STRENGTH ANALYSIS

BUT WHEN I HAVE TO RUN FOR SERVICEABILTY WITHOUT LOAD ENVELOPE IT WILL NOT CHECK FOR DFF IS THAT CORRECT? SO WHAT I WILL HAVE DO.

PLEASE ADVISE

large load combination

Ajay Datta — Mon, 13 May 2019 03:46:36 GMT

communities.bentley.com/.../Copy-of-Attachment-2B_5F00_DUQM_5F00_SHELTER-LC_5F00_STRENGTH_5F00_REV_2D00_O1-_2D00_29_2D00_4_2D00_2019.xls

I am sorry this is not a staad analysis problem but excel macro. I have generated large load combinations using excel. However I am unable to INSERT the text REPEAT LOAD after each LOAD XXXX line AS SHOWN BELOW. I am sure someone can help me with a proper VB macro or any other way.

*2001 1.4 Ds + 1.4 DF + 1.4 DOT + 1.4 DOP + 1.4 FFT + 1.4 FFL + 1.4 AFT

* + 1.4 AFL + 1.4 CRD- 1/1

LOAD 2001

REPEAT LOAD

5 1.4 6 1.4 7 1.4 9 1.4 18 1.4 19 1.4 20 1.4 21 1.4 27 1.4

*2002 1.4 Ds + 1.4 DF + 1.4 DOT + 1.4 DOP + 1.4 FFT + 1.4 FFL + 1.4 AFT

* + 1.4 AFL + 1.4 CRD- 1/2

LOAD 2002

REPEAT LOAD

5 1.4 6 1.4 7 1.4 9 1.4 18 1.4 19 1.4 20 1.4 21 1.4 28 1.4

*2003 1.4 Ds + 1.4 DF + 1.4 DOT + 1.4 DOP + 1.4 FFT + 1.4 FFL + 1.4 AFT

* + 1.4 AFL + 1.4 CRD- 2/1

LOAD 2003

REPEAT LOAD

5 1.4 6 1.4 7 1.4 9 1.4 18 1.4 19 1.4 20 1.4 21 1.4 29 1.4

*2004 1.4 Ds + 1.4 DF + 1.4 DOT + 1.4 DOP + 1.4 FFT + 1.4 FFL + 1.4 AFT

* + 1.4 AFL + 1.4 CRD- 2/2

LOAD 2004

REPEAT LOAD

5 1.4 6 1.4 7 1.4 9 1.4 18 1.4 19 1.4 20 1.4 21 1.4 30 1.4

INSTABILITY WARNING

Ajay Datta — Sat, 25 May 2019 06:08:32 GMT

HELLO I AM UNABLE TO FIND THE REASON FOR INSTABILITY WARNING. CAN ANY ONE HELP?communities.bentley.com/.../CAR-PARK-Frame-_28002B002D00_TEMP-_2B00_X-_2D00_X-NOTIONAL-_2B00_Z-_2D00_Z_2900_--8-FRAMES-member-tension-PDELTA_2800_PIPE_2900_INSTABILTY.std

Ram connection report in metric unit

Ajay Datta — Wed, 22 May 2019 03:57:34 GMT

Hello I have run the staad file with metric(MKS) unit configuration in connect edition. But the Ram connection report is produced in FPS system.

Can you advise how to resolve this matter communities.bentley.com/.../CAR-PARK-Frame-_28002B002D00_TEMP-_2B00_X-_2D00_X-NOTIONAL_2900_--8-FRAMES-member-tension-PDELTA_2800_PIPE_2900_.std communities.bentley.com/.../CAR-PARK-Frame-_28002B002D00_TEMP-_2B00_X-_2D00_X-NOTIONAL_2900_--8-FRAMES-member-tension-PDELTA_2800_PIPE_29005F00_Report.doc

serviceability load combination with seimic load

Ajay Datta — Mon, 13 May 2019 11:48:37 GMT

Sorry my earlier question on this subject was wrong

The term should be System Overstrength Factor OMEGA

The correct question is

WE ARE SUPPOSED TO CONSIDER System Overstrength Factor OMEGA=3

FOR STRENGTH DESIGN A TYPICAL LOAD COMBINATION AS GIVEN BELOW

**EMPTY WEIGHT +THERMAL +SEISMIC
**X DIR
LOAD 105 : DEAD (0.6-.2X.152) +SS +TEMP +3 X 0.7SEIS(+X) +NOTIONAL X
REPEAT LOAD
1 0.5696 41 0.6 42 0.6 2000 2.1 14 2.1 3001 0.6 3007 0.7

**Z DIR
LOAD 107 : DEAD (0.6-.2X.152) +SS +TEMP +3 X 0.7SEIS(+Z) +NOTIONAL X
REPEAT LOAD
1 0.5696 41 0.6 42 0.6 2001 2.1 14 2.1 3001 0.6 3007 0.7

MY QUESTION IS DO I HAVE TO CONSIDER System Overstrength Factor OMEGA IN THE SERVICEABILTY LOAD COMBINATION TOO?

PRETENSION IN TIE ROD FOR CANTILEVER ROOF STRUCTURE

Ajay Datta — Wed, 08 May 2019 07:48:38 GMT

IN MY PROBLEM I GET A DOWNWARD VERTICAL DEFLECTION OF 92MM WHICH IS MORE THAN ALLOWABLE(SPAN/90=72MM). I WANT TO APPLY PRETENSION IN THE TIE ROD TO REDUCE THIS DEFLECTION. HOW TO HANDLE THIS PROBLEM CAN ANYONE ADVICE? IS IT BY TRIAL AND ERROR METHOD.communities.bentley.com/.../CAR-PARK-Frame-_28002B002D00_TEMP-_2B00_X-_2D00_X-NOTIONAL_2900_--8-FRAMES-member-truss-direct-analysis_2800_UB_2900_-SERVICABILTY.std

ERROR IN USER TABLE

Ajay Datta — Tue, 07 May 2019 08:49:10 GMT

I WANT TO USE 50MM SOLID ROD AS TIE MEMBER TO CARRY ONLY TENSION FOR WHICH I CREATED THE FOLLOWING USER TABLE

WHAT IS WRONG? I GET THE ERROR?

START USER TABLE

TABLE 1

UNIT MM KN

PIPE

PIP50

50 0.05

END

**ERROR READING THE ABOVE USER TABLE # 1

section-name: PIP50

CHECK THE NUMBER OR VALUES OF PARAMETERS ENTERED.

Direct analysis with tension member

Ajay Datta — Mon, 06 May 2019 08:04:29 GMT

In my analysis program I am getting error and unable to find the reason. Can anyone help me?communities.bentley.com/.../CAR-PARK-Frame-_28002B002D00_TEMP-_2B00_X-_2D00_X-NOTIONAL_2900_-single-frame-_2D00_-8-FRAMES.std

LIMCON in conjunction with STAAD PRO

Ajay Datta — Mon, 29 Apr 2019 11:38:07 GMT

Hello I use RAM connection program in conjunction with Staad Pro analysis program where in for any connection design the forces in a member/joint is directly available from Staad.

However I never used LIMCON. Can I use LIMCON in conjunction with Staad pro Analysis to get the forces for connection design? Can anybody give few steps to start with my practice?