Load Combinations Using Moving Loads

RE: Load Combinations Using Moving Loads

xl 5889 — Tue, 01 Jun 2021 04:33:52 GMT

Can i do it directly on GUI without using Staadeditor ? I am not familiar with editor though , this is prone to mistake

RE: Load Combinations Using Moving Loads

Matt Kline — Fri, 15 Jan 2016 13:56:38 GMT

Here is a model that will combine the moving loads into the load combinations. It is rather impractical on a large scale due to the number of load cases the moving loads generate and the associated analysis time, but it seems this is the only way to do it...

You need to create your "load combinations" as REPEAT LOADS. You then need to ADD LOAD these repeat loads to the generates moving load. You would also need to create multiple VEHICLE DEFINITIONS in order to get the correct load factor on the generated moving load.

STAAD SPACE
START JOB INFORMATION
ENGINEER DATE 14-Jan-16
END JOB INFORMATION
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 0 0 20;
MEMBER INCIDENCES
1 1 2;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+006
POISSON 0.3
DENSITY 0.489024
ALPHA 6e-006
DAMP 0.03
TYPE STEEL
STRENGTH FY 5184 FU 8352 RY 1.5 RT 1.2
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
1 TABLE ST W14X22
CONSTANTS
MATERIAL STEEL ALL
SUPPORTS
1 2 PINNED
DEFINE MOVING LOAD
TYPE 1 LOAD 1
DIST 0
TYPE 2 LOAD 0.75
DIST 0
LOAD 1 LOADTYPE Dead TITLE DEAD
SELFWEIGHT Y -1
LOAD 2 LOADTYPE Live REDUCIBLE TITLE LIVE
MEMBER LOAD
1 UNI GY -0.5
1 CON GY -10 10
LOAD 3 LOADTYPE Wind TITLE WIND +X
MEMBER LOAD
1 UNI GX 0.05
LOAD 4 LOADTYPE Wind TITLE WIND -X
MEMBER LOAD
1 UNI GX -0.05
LOAD 101 D+L
REPEAT LOAD
1 1.0 2 1.0
LOAD 102 D+.75(L+WX)
REPEAT LOAD
1 1.0 2 0.75 3 0.75
LOAD 103 D+.75(L-WX)
REPEAT LOAD
1 1.0 2 0.75 4 0.75
LOAD 104 0.6D+WX
REPEAT LOAD
1 0.6 3 1.0
LOAD 105 0.6D-WX
REPEAT LOAD
1 0.6 4 1.0
LOAD GENERATION 30 ADD LOAD 101
TYPE 1 0 0 0 ZINC 1
LOAD GENERATION 20 ADD LOAD 102
TYPE 2 0 0 0 ZINC 1
LOAD GENERATION 20 ADD LOAD 103
TYPE 1 0 0 0 ZINC 1
PERFORM ANALYSIS
PARAMETER 1
CODE AISC UNIFIED 2010
CHECK CODE ALL
FINISH

Re: Load Combinations Using Moving Loads

DSANJU — Wed, 16 Oct 2013 15:35:17 GMT

You can simply use STAAD editor to create load combination with the generated moving load. You may refer to the attached example model. In this model, the following primary loads have been created:

LOAD 1 LOADTYPE None TITLE DL

SELFWEIGHT Y -1

LOAD 2 LOADTYPE None TITLE IMPOSED LOAD

MEMBER LOAD

7 TO 11 18 TO 22 29 TO 33 40 TO 44 51 TO 60 UNI GY -4

LOAD 3 LOADTYPE None TITLE WL

JOINT LOAD

7 TO 30 FX 1

It also has the following moving load generation command:

LOAD GENERATION 10 ADD LOAD 1

TYPE 1 2.25 0 0 ZINC 3

Now, if you want to create a load combination with the generated load case 5, you can simply type the following command

LOAD COMB 15 COMBINATION LOAD CASE 15

1 1.0 2 1.0 3 1.0 4 1.0 5 1.0

The first integer number is the primary bload case number and the next one is the load factor. Here, the load factor is 1.0. I hope this helps.

Re: Load Combinations Using Moving Loads

uncblue — Mon, 14 Oct 2013 23:13:33 GMT

Have you tried adding repeat loads through the input file?  You can't do this through the gui.  For example,

LOAD 1 LOADTYPE None  TITLE DEAD LOAD
SELFWEIGHT Y -1 
LOAD 100 LOADTYPE None  TITLE MOVING LOAD GENERATION START #
LOAD GENERATION 10
TYPE 1 0 0 0 ZINC 1
LOAD 1001 LOADTYPE None  TITLE LOAD CASE 1001
REPEAT LOAD
1 1.0 101 1.0