Bridge truss Static Equilibrium

In summary, the conversation discusses the calculation of the force of tension or compression in each structural component of a bridge truss that extends 214 m across a river and is allowed to slide horizontally for thermal expansion. The method of joints is recommended for solving for the force in T_AC, which can be found as the horizontal component of the force in T_AB using the cosine of the angle between them. The use of Lami's Theorem and moment equations are also mentioned as potential methods for finding the force.
  • #1
pegasus24
14
0

Homework Statement


A bridge truss extends x = 214 m across a river (Fig. P12.68) where θ = 35°. The structure is free to slide horizontally to permit thermal expansion. The structural components are connected by pin joints, and the masses of the bars are small compared with the mass of a 1270 kg car at the center. Calculate the force of tension or compression in each structural component.

Homework Equations


Lami's Theorem
A/sin a = B/sin b = C/sin c

The Attempt at a Solution


I found the forces in most of the members except T_AC and T_CE.
How do i find the force? Should I use moment equation? Is so how should I apply it?
 

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  • #2
If you have correctly solved for the force in AB, then T_AC is just the horizontal component of the force in AB. Use the method of joints.

Welcome to PF!:smile:
 
  • #3
PhanthomJay said:
If you have correctly solved for the force in AB, then T_AC is just the horizontal component of the force in AB. Use the method of joints.

Welcome to PF!:smile:

Thanks a lot.. I got it right now.. T_AC = T_AB cos 35
 

1. What is a bridge truss?

A bridge truss is a structure made up of multiple triangular units connected together to form a strong and stable framework. It is commonly used in bridge construction to support heavy loads and maintain structural stability.

2. How does a bridge truss achieve static equilibrium?

In order for a bridge truss to achieve static equilibrium, the sum of all the forces acting on it must be equal to zero. This means that the forces acting upwards (tension) must be balanced by the forces acting downwards (compression).

3. What is the purpose of calculating the forces in a bridge truss?

Calculating the forces in a bridge truss is important in ensuring that the structure is able to support the expected load without collapsing. It also helps engineers determine the most efficient and cost-effective design for the bridge.

4. How does the shape of a bridge truss affect its strength?

The shape of a bridge truss can greatly impact its strength. Triangular shapes are the most commonly used in bridge trusses because they distribute weight evenly and efficiently. A wider base and narrower top also helps to distribute the load and increase stability.

5. Are there different types of bridge trusses?

Yes, there are several different types of bridge trusses, including Warren, Pratt, and Howe trusses. Each type has its own unique design and is used for different purposes depending on the span and load requirements of the bridge.

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