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., 3^rd edition, 1956, p.346, problem 3.

Problem

Determine the horizontal reaction at support 4 of the system.

L = 50 in.

P = 10 kips

Plane truss

Comparison

Table 1. Comparison of results
Result Type	Theory	STAAD.Pro	Difference
R₄ (kips)	8.77	8.77	none

STAAD Input

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
LOAD 1
JOINT LOAD
2 FY -10
PERFORM ANALYSIS
PRINT SUPPORT REACTION
FINISH

STAAD Output

   SUPPORT REACTIONS -UNIT KIP  INCH    STRUCTURE TYPE = TRUSS
   -----------------
 JOINT  LOAD   FORCE-X   FORCE-Y   FORCE-Z     MOM-X     MOM-Y     MOM Z
      1    1      8.77      5.00      0.00      0.00      0.00      0.00
      4    1     -8.77      5.00      0.00      0.00      0.00      0.00