Lattice Truss Bridge

Introduction

Lattice Bridge is a type of a truss bridge in which diagonally and closely linked bars are used that make a lattice. It has been under the patent name of an architect in ithiel town and was in the 1820 and 1835 as a town's lattice truss. The trusses can be assembled by bolting, riveting or by welding, and this structure is easy to assemble and is less expensive.

This design was originally created to enable the architects to make a bridge from planks by employing a less skilled labor instead of the use of heavy timbers and high cost carpenters. This form was also constructed by using relatively light iron or steel and that is also in a large quantity which reduces the weight of the bridge and the diagonal adjustments of the iron or steel elements which gives the strength and steadiness to the bridge (Jackson, 92).

The shutters of the bridge can be constructed with different materials like steel, wood, aluminum, etc. In the lattice of nodes articulation, the bending is negligible as long as the charges which are applied in the lattice knots are fixed to the bars.

A lattice is statically determinate or fully Iso static if applied on the equations of mechanical equilibrium, first it uses the entire structure to determine their reactions, and then to the internal parts to determine the efforts on each of the elements. These two conditions are called internal Iso static and external iso static these are further explained below:

External Iso Static

External Iso static is where reactions can be calculated using only the equations of statics. In order for that to happen, the number of degrees of freedom eliminated by the handles is that the several of the lattices must be at most three, because there are only three independent equations of the static applied throughout the structure.

Internal Iso Static

If it is possible to determine the internal forces of each of the bars that form the structure, as we will, In order for this to happen this process will require a certain relationship between the number of bars and knots.

A flat lattice can only be iso static if formed by knots and bars which are articulated efforts only to transmit to other bars in the direction of its axis. This implies that in a flat lattice it should be statically determined by the bending moment which is zero ...