Human life should be given priority in assessing risk because no value can be attached to it and then other factors to follow.
There are ways of assessing risk in the existing civil engineering facilities in an attempt to come up with decision making tools. Risk is the measure of the probability and severity of adverse effects (Lowrance, 1976) while risk assessment is the act of determining the likelihood of a risk occurring and the consequences that come with it. For sustainable development to be achieved, intense focus on risk assessment has to be put in order to maintain the existing and future infrastructure. Determining what should be done in case of occurrence of a risk, impact of current decisions on future options and the consequences due to a given activity is also part of risk management. Due to day to day changes in systems, technology and environment, risk management has to be monitored regularly.
This is the first step of risk assessment. It is the act of identifying the sources of risk in the existing civil engineering facilities. Some of the sources of risk are human error, environmental catastrophes and system failure due to mechanical breakdown. These hazards can be identified by past experience and also in incident data banks where past records are kept. It is very important to take into account all the relevant hazards in a facility. This ensures critical decisions are made in regard to the risks. Ignoring a hazard causes negative impacts in terms of financial losses and human injuries or even lives may be at stake.
Logic tree analysis provides a tool for assessing various branching probabilities divided into, fault trees, event trees and consequence charts. Fault trees explain the source of failures.