STAAD.Pro Help

AD.2005.2.1 Floor Vibration Analysis

The adequacy of a floor system from the standpoint of its vibration serviceability due to human activity, specifically walking excitation, can now be assessed using STAAD.Pro. The procedures of Chapters 3 and 4 of the AISC Steel Design Guide Series No. 11 - Floor Vibrations due to Human Activity - have been implemented.

Tutorial Problem

A composite deck is system composed of a concrete slab lying over a steel deck with or without ribs. The steel deck in turn is supported by steel beams or joists and they span the distance between girders and are supported by those girders. The slab may or may not be connected to the joists by shear studs.

To model this system in STAAD, one has to go to Geometry > Composite Deck from the left side of the screen as shown in the next figure:



The Composite Deck dialog opens on the right side of the screen as shown in the next figure.



When you click on the Create New Deck tab, you will see the mouse cursor change to look like an icon of a colored composite deck. To define the periphery of the composite deck, click the corner nodes in clockwise or counter-clockwise sequence using this mouse cursor. The last click must be on the starting node to close the periphery. In the figure shown, the sequence used is A-B-C-D-A.



The name of the composite deck will appear in the Composite Deck dialog. Click on that name and then dialog box will display several additional contents as shown in the next figure



In the main view, the composite deck will appear in hatched lines. An arrow mark will indicate the direction along which the composite deck spans. This arrow will appear by default. To change the span direction, select two beams whose X axis is perpendicular to the intended span direction, and click on the tab Create Direction.

Define the concrete properties, rib properties and connectivity details in the appropriate fields of the Composite Deck dialog. To save the properties, click on the tab Update Deck Property (see previous figure). A sample data set is shown in the next figure

Command in the STAAD Input File

When the data is specified in the dialog boxes as we saw earlier, it is also simultaneously stored in the STAAD input file in the appropriate command syntax. For the data we specified previously, the corresponding editor input will be as follows:

START DECK DEFINITION
_DECK FLOOR1
PERIPHERY 1 TO 8
DIRECTION -1.000000 0.000000 0.000000
COMPOSITE 10 9 4 8
OUTER 1 4 8 5
DIA 0.000
HGT 0.000
CT 0.271
FC 576.000
RBW 2.000
RBH 0.167
SHR 0
VENDOR NONE
CD 0.110
CMP 2.0
CW 10.000000 MEMB 10
CW 10.000000 MEMB 9
CW 5.000000 MEMB 4
CW 5.000000 MEMB 8
END DECK DEFINITION

Floor Vibration Report

In order to obtain the report, the finished model must be successfully analyzed. Go to the post-processing mode. Select Report > Floor Vibration Report as shown in the next figure.



The Floor Vibration Output dialog as shown in the next figure will appear. Select the deck name, the load case, and click on Check to see the report.



  1. Select the composite deck from the drop-down list.
  2. Select the load case.
  3. Click Check.

An output similar to the one shown below will appear.



The terms displayed in the above box have been explained earlier.

Example STAAD Input File

STAAD SPACE
INPUT WIDTH 79
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 10 0 0; 3 20 0 0; 4 30 0 0; 5 0 0 35; 6 10 0 35; 7 20 0 35;
8 30 0 35; 9 0 -15 0; 10 30 -15 0; 11 0 -15 35; 12 30 -15 35; 13 0 15 0;
14 30 15 0; 15 0 15 35; 16 30 15 35; 17 10 15 0; 18 20 15 0; 19 20 15 35;
20 10 15 35;
MEMBER INCIDENCES
1 1 2; 2 2 3; 3 3 4; 4 4 8; 5 8 7; 6 7 6; 7 6 5; 8 5 1; 9 2 6; 10 3 7; 11 1 9;
12 4 10; 13 5 11; 14 8 12; 15 1 13; 16 4 14; 17 5 15; 18 8 16; 19 13 17;
20 17 18; 21 18 14; 22 14 16; 23 16 19; 24 19 20; 25 20 15; 26 15 13; 27 17 20;
28 18 19;
DEFINE MATERIAL START
ISOTROPIC STEEL
E 4.176e+006
POISSON 0.3
DENSITY 0.489024
ALPHA 6.5e-006
DAMP 0.03
END DEFINE MATERIAL
MEMBER PROPERTY AMERICAN
4 8 TO 18 22 26 TO 28 TABLE ST W18X35
1 TO 3 5 TO 7 19 TO 21 23 TO 25 TABLE ST W21X50
START DECK DEFINITION
_DECK C2
PERIPHERY 1 TO 8
DIRECTION -1.000000 0.000000 0.000000
COMPOSITE 10 9 4 8
OUTER 1 4 8 5
DIA 0.000000
HGT 0.000
CT 0.271
FC 576.000
RBW 2.000
RBH 0.167
SHR 0
VENDOR NONE
CD 0.110
CMP 2.0
CW 10.000000 MEMB 10
CW 10.000000 MEMB 9
CW 5.000000 MEMB 4
CW 5.000000 MEMB 8
_DECK C3
PERIPHERY 19 TO 26
DIRECTION -1.000000 0.000000 0.000000
COMPOSITE 28 27 22 26
OUTER 13 14 16 15
DIA 0.000000
HGT 0.000
CT 0.800
FC 476.000
RBW 0.500
RBH 0.500
SHR 0
VENDOR NONE
CD 0.150
CMP 2.0
CW 10.000000 MEMB 28
CW 10.000000 MEMB 27
CW 5.000000 MEMB 22
CW 5.000000 MEMB 26
END DECK DEFINITION
CONSTANTS
MATERIAL STEEL MEMB 1 TO 28
SUPPORTS
9 TO 12 FIXED
LOAD 1 LOADTYPE None  TITLE LOAD CASE 1
SELFWEIGHT Y -1
UNIT FEET POUND
ONEWAY LOAD
YRANGE 0 0 ONE -57 GY
UNIT FEET KIP
PERFORM ANALYSIS PRINT STATICS CHECK
FINISH