Learning Lab Denmark - INCUBEus

E. Bridges and Dams

In a so-called psychometric study from 1979 (Slovic 2000) the participants rated the perceived benefit from large constructions such as bridges and dams somewhat higher than the perceived risk.

Unlike many other technologies, the public level of risk acceptance is thus quite high. This could be explained by familiarity (Waddick, p. 4). People tend to have a more positive attitude towards a familiar technology. If one faces the risk every day and the risk appears to have a very low probability, as could be the case with a bridge frequently crossed, the tendency is to disregard the risk.

The systems in the construction industry are linear and tightly coupled, which means that if one pillar in a bridge is removed, the entire bridge will collapse. Accidents concerning bridges and dams can have severe consequences; they often incur many victims. With the collapse of Mapasset Dam, for example, two villages and a highway were drunkened (see card #E3).

Apart from the familiar reasons, that bridge and dam accidents occur due to human error and poor maintenance, the reason for many accidents is lack of engineering knowledge. Historically, the construction industry has developed by means of trial and error, and each accident has helped improve the next construction, as was the case with St. Francis Dam (see card #E1).

Further reading:
Perrow, C. (1984/1999) Normal accidents. Living with High-Risk Technologies, pp. 232-255, Princeton University Press.

Report about risks in the building industry by Phil Waddick:

Slovic, P. (2000) The Perception of Risk, pp. 80-103, Earthscan Publications.

Comment this page

Nine Technologies

A. Air Transport
B. Buildings
C. Land Transport
D. Marine Transport
E. Bridges and Dams
F. Oil Tankers
G. Chemical Industry
H. Medical Industry
I. Nuclear Industry

Nine Theories

Quantitative Risk Assessment
Decision Analysis
Cost-benefit Analysis
Normal Accident Theory
High Reliability Organisations
Risk communication
Arena Theory
Cultural Theory

Five Categories

Hazard (0-1000)
Range (km2)
Fear Factor (0-10)
Media Effect (0-100)