Failures and collapses of bridge constructions, analysis of their causes. Part 3
The article acknowledges that engineers try to avoid the appearance of the bridge failure, and in case of destruction they investigate the causes of emergency situations and develop the ways to prevent their occurrence. It also specifies that, during the development of the newer normative documents ensuring the design of more secure bridges, the experience and lessons learned of the mistakes that caused the collapses and destructions of bridges are being used. The destruction of a bridge can lead to such effects: · interruption of traffic on the relevant road; the necessity to engage the police and ambulance to solve conflicts and to assist the victims; · the necessity to arrange a new bypass road or even to find an alternate route; · the necessity to take care of emergency repairs with further repair of structure in order to restore it; · forensic examinations in order to find out the level of guilt of participants in the project; · the need for a bridge reconstruction; the damaged bridges to be replaced with more effective structures using the modern ways of design and construction. The paper describes the classification of special (emergency) impacts in accordance with the National appendix to Eurocode EN 1991-1-7. In the next part of the paper you can see some examples of the bridge failures with analysis of the reasons, the following types of failures are being considered: the failures due to inadequate reliability and connection disruption; the failures due to non-compliance with established loading gauge and the impacts of vehicular live loads; the failures due to the lack of technical supervision; the failures due to the appearance of additional stresses and deformations because of geological, hydrologic, landslide developments and seismic events.