This is a two dimensional truss structure with 32 feet height and 96 feet span. The top chord of the truss is subjected to temperature rise of 50 degrees Fahrenheit. The coefficient of thermal expansion for the material is 0.0000065 in/in/F. The elastic modulus is 30,000,000 psi. Determine the member forces in the structure.

The material properties of the truss are given as:

Modulus of Elasticity = 30,000,000 lb/in2

Coefficient of Thermal Expansion = 0.0000065 in/in/oF

The sectional properties are:

Area = 24 in2 Designation = S1 Top & Bottom

Area = 32 in2 Designation = S2 Vertical Bars

Area = 40 in2 Designation = S3 Diagonal Bars

The truss model has 8 joints and 12 truss elements. The rotations (about X, Y and Z) and translation in Y-direction are eliminated. Joint 1 is pin support and joint 8 is a roller in horizontal direction.

The temperature rise on the top chord is specified for elements 13 and 14.

Tested Features

App

Object Link: https://openbrim.org/objidqt27dbteobdk8pidmk4cwb.project

Library

Object Link: https://openbrim.org/objid894neebqisi9ixmnf35aku.libobj

Sources

Hsieh, Y.Y., "Elementary Theory of Structures," Prentice-Hall, Inc., 1970, pp. 200-202.
LARSA 4D

Result Comparison

	Independent (Hsieh)	Larsa	OpenBrIM	Percent Difference (Larsa vs Independent)	Percent Difference (OpenBrIM vs Independent)
F1	0.00	0.00	0.00	0%	0%
F2	0.00	0.00	0.00	0%	0%
F3	-21.1	-21.06	-21.06	-0.1896%	-0.1896%
F4	0.00	0.00	0.00	0%	0%
F5	0.00	0.00	0.00	0%	0%
F6	0.00	0.00	0.00	0%	0%
F7	0.00	0.00	0.00	0%	0%
F8	-28.1	-28.08	-28.08	-0.0712%	-0.0712%
F9	35.1	35.1	35.1	0%	0%
F10	35.1	35.1	35.1	0%	0%
F11	-28.1	-28.08	-28.08	-0.0712%	-0.0712%
F12	0 00	0 00	0 00	0%	0%
F13	0.00	0.00	0.00	0%	0%
F14	-21.1	-21.06	-21.06	-0.1896%	-0.1896%

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