# V. Reactions in a 2D Truss Model 1

To find support reactions due to joint loads in a plane truss.

## Reference

McCormack, J.C. Structural Analysis, Intext Educational Publishers, 3rd Edition, 1975.

## Problem

Find the vertical support reactions of the truss.

 E = 30,000.0 ksi

 A = 100 in2

## Comparison

Table 1. Comparison of results
R1 (kips) -76.7 -76.67 none
R4 (kips) 346.7 346.67 none
R9 (kips) 30 30 none

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\02 Trusses\Reactions in a 2D Truss Model 1.STD is typically installed with the program.

``````STAAD TRUSS :A PLANE TRUSS
START JOB INFORMATION
ENGINEER DATE 18-Sep-18
END JOB INFORMATION
*
* REFERENCE: MCCORMAC, J.C.,"STRUCTURAL ANALYSIS", INTEXT
*            EDUCATIONAL PUBLISHERS, NEW YORK, 3RD EDITION, 1975.
*
INPUT WIDTH 72
UNIT FEET KIP
JOINT COORDINATES
1 0 0 0; 2 30 0 0; 3 60 0 0; 4 90 0 0; 5 120 0 0; 6 150 0 0; 7 180 0 0;
8 210 0 0; 9 240 0 0; 10 0 20 0; 11 30 20 0; 12 60 20 0; 13 90 20 0;
14 120 20 0; 15 150 20 0; 16 180 20 0; 17 210 20 0; 18 240 20 0;
MEMBER INCIDENCES
1 1 2; 2 2 3; 3 3 4; 4 4 5; 5 5 6; 6 6 7; 7 7 8; 8 8 9; 9 10 11;
10 11 12; 11 12 13; 12 13 14; 13 14 15; 14 16 17; 15 17 18; 16 1 10;
17 10 2; 18 2 11; 19 11 3; 20 3 12; 21 12 4; 22 4 13; 23 13 5; 24 5 14;
25 14 6; 26 6 15; 27 15 7; 28 7 16; 29 16 8; 30 8 17; 31 17 9; 32 9 18;
UNIT INCHES KIP
MEMBER PROPERTY AMERICAN
1 TO 32 PRIS AX 100
* MEMBER TRUSS
* 1 TO 32
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 30000
POISSON 0.290909
END DEFINE MATERIAL
CONSTANTS
MATERIAL MATERIAL1 ALL
SUPPORTS
1 PINNED
4 9 FIXED BUT FX MZ
6 TO 8 FY -60
3 FY -80
2 FY -40
PERFORM ANALYSIS
PRINT SUPPORT REACTION
FINISH
``````

```   SUPPORT REACTIONS -UNIT KIP  INCH    STRUCTURE TYPE = TRUSS