Maintenance Requirements and Capability

7_StreambankManual
Page Navigation
85

Evaluating this factor involves weighing a lower initial cost or construction

expediency against the potential for deterioration of the project as a result of inadequate

inspection and maintenance.

If the project sponsor has the capability to monitor the condition of the project, and

maintain it as required, a less durable technique may be preferable to a more durable method

requiring a higher initial investment. This is particularly likely if inexpensive labor, equipment,

and local materials are available. However, the engineer should be cautious about relying too

heavily on future maintenance capability, for two reasons:

The capability of the sponsors to maintain the project may change due to

factors beyond their control; and

Human nature may make it easier for the sponsor to agree to an obligation to

be incurred in the future than to fulfill that obligation when it comes due.

This is a project-specific determination, but a decision to select a less durable

technique should not be made without a frank, even pessimistic, evaluation of the sponsor's

long-term commitment and capability, and the durability of the protection methods being

considered.

The consequences of failure of the project are linked both to maintenance

requirements and to the determination of required durability. However, it is more critical to

the detailed design of the project than to the selection of a particular method, since most

methods can be designed with a low risk of failure. This is discussed further in 6.6, "Safety

Factor."

5.1.1.3 Climatic Conditions

Climatic conditions affect durability through the action of:

Freezing and thawing cycles;

Ice floes;

Heaving;

Wetting and drying cycles; and

Sunlight (ultraviolet deterioration).

The primary vulnerabilities here are the effect of freezing and thawing on stone, the

effect of ice floes on armor and indirect protection structures, the effect of heaving on slope

armoring, the effect of wetting and drying (with the accompanying damage by bacterial

growth and insects, on wooden components), and the effect of sunlight on synthetic materials.