Conclusions from Observation the Small Crisp Arch Bridges Located on Mining Areas

In the paper remarks, observations and conclusions from the long-term observation of a three small crisp arch bridges located on mining areas are described. In the article three different methods of mining protection of arched bridges are discussed, the effectiveness of these protections differs in the significant way. It is shown, that the most of damages are not made by mining deformations but damages are made by incorrectly protection to mining influences, lack of small and often cheap mining preventive action or as a result of simply atmospheric factors. Arch structures are able to carry in a lot of greater deformations of the area than frame bridges with the similar span and what's more practically almost without any damages. Probably the cooperation of the soil-ground with the arch is important; so that the protection to mining influences should aspire for providing such cooperation. The relieving of the arch conducts to destruction of construction, what is described in the paper in one of examples.