scope:

The scope of this process relates to the structural assessment of structures (and their elements) for which Network Rail has responsibility, either as the owner or as a result of specific agreement.
It specifically applies to the following asset types and blocks: 
a) Underline bridges 
b) Overline bridges 
c) Footbridges 
d) Culverts (except where the primary method of support is by arching action) 
e) Undercrofts 
f) Canopies 
g) Train and depot sheds 
h) Tunnels that directly support external traffic loads 
i) Side bridges 
j) Other Structures where examination of condition alone is insufficient to inform management decisions. 
Further guidance on the requirements for structural assessment of different asset types and blocks is provided in Module 1 and Module 2. 
This document is mandated for use by everyone managing and assessing the load capacity of existing structures. 
Do not use structural assessment techniques for design unless directed by structures controls for 'design, construct and commission' or specifically instructed by a representative of Network Rail.
Purpose 
This Manual sets out the procedures for managing the load capacity of structures through structural assessment and carrying out structural assessments. 
Structural assessment is a form of structural analysis that uses the existing geometry, dimensions, material properties and contemporary condition of a structure to understand its load capacity. 
It helps to mitigate the risk of functional failure of the structure.