# V. Reactions in a 2D Truss Model 3

Find the support reactions due to a joint load in a plane truss.

## Reference

Timoshenko, S., Strength of Materials, Part 1, D. Van Nostrand Co., Inc., 3rd edition, 1956,  p.346, problem 3.

## Problem

Determine the horizontal reaction at support 4 of the system.

L = 50 in.

P = 10 kips

## Comparison

Table 1. Comparison of results
R4 (kips) 8.77 8.77 none

The file C:\Users\Public\Public Documents\STAAD.Pro CONNECT Edition\Samples\ Verification Models\02 Trusses\Reactions in a 2D Truss Model 3.STD is typically installed with the program.

``````STAAD TRUSS : REACTION IN TRUSS
START JOB INFORMATION
ENGINEER DATE 18-Sep-18
END JOB INFORMATION
*
*  REFERENCE `STRENGTH OF MATERIALS' PART-1 BY S. TIMOSHENKO
*  PAGE 346 PROBLEM NO. 3. THE ANSWER IS REACTION = 0.877P.
*  THEREFORE IF P=10, REACTION = 8.77
*
UNIT INCHES KIP
JOINT COORDINATES
1 0 0 0; 2 150 100 0; 3 150 50 0; 4 300 0 0;
MEMBER INCIDENCES
1 1 2; 2 1 3; 3 2 3; 4 2 4; 5 3 4;
MEMBER PROPERTY AMERICAN
1 4 PRIS AX 5
2 5 PRIS AX 3
3 PRIS AX 2
DEFINE MATERIAL START
ISOTROPIC MATERIAL1
E 30000
POISSON 0.3
END DEFINE MATERIAL
CONSTANTS
MATERIAL MATERIAL1 ALL
SUPPORTS
1 4 PINNED
2 FY -10
PERFORM ANALYSIS
PRINT SUPPORT REACTION
FINISH
``````

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