Soil-Steel Bridges

The chapter contains a general introduction to the soil-steel bridges and culverts (terminology, difference between the bridge and culvert, advantages and disadvantages, overall classification). Financial benefits resulting from the use of the soil-steel bridges versus typical steel and reinforced concrete bridges for transportation investments is also briefly presented on the basis of the literature review. A historical outline of development of such bridges is presented. Besides, the technological, design and scientific problems appearing in the soil-steel bridges are shortly described. The author defined eight different stages of structural analysis of soil-steel bridges taking into account primarily the various loads appearing during construction stage and normal operation (static, dynamic, service, seismic, anthropogenic). At the end of the chapter, the most commonly used terms related to the soil-steel bridges are also shown and defined.

The chapter contains an introduction to the design of soil-steel bridges (applied theories and methods). Three most commonly used methods of designing soil-steel bridges are presented in detail. The first method developed by Hakan Sundquist and Lars Pettersson (known as the Swedish Design Method) is described. American Association of State Highway and Transportation Officials (AASHTO method) and Canadian Highway Bridge Design Code (CHBDC method) also proposes the calculation methods of soil-steel bridges (they constitute the second and third methods, respectively). Besides, the procedure of design of soil-steel bridges with long span (exceeding 8.0 m) is also shown. Discussion of the selected calculation results using design methods compared with test results is presented. Next, the construction methods of the soil-steel bridges is described. In addition, the method of reinforcing of old bridges using the corrugated steel plates is also shown. The most commonly construction and design errors occurring at the soil-steel bridges are presented on the real examples. The finite element analyses of the soil-steel bridges are described taking into account the crucial model-ling elements such as interface, modelling of corrugation plates, soil models. The selected results of numerical analyses are presented for the box culvert, pipe-arch, arch structure with reinforced concrete slab, and arch with flat plates versus corrugated. At the end the general conclusions of finite element analysis of the soil-steel bridges are given.

The chapter includes an introduction to corrosion problem of soil-steel bridges (classification, reason of corrosion occurs). Chemical and electrochemical corrosion of corrugated steel plates are shortly described. The beginning of the corrosion process in soil-steel bridges is also presented. The flow of stray currents around soil-steel bridges is also shown as the causing corrosion in the railway and tram bridges. Soil corrosivity problem is undertaken taking into account the soil resistivity, pH, moisture content. Atmospheric corrosion including the changes in air caused by acidification of the environment and its influence upon corrosion is described. Corrosion in water and erosion-abrasion damages of the corrugated steel plates are also shown. Mathematical model of corrosion description of a soil-steel bridge including the model of corrosive damage and formation of corrosive cracks, is proposed. At the end of chapter, the protections against corrosion and abrasion in soil-steel bridges and culverts are presented. A practical example of designing durability of soil-steel bridge is also given.

The chapter contains the durability problem of soil-steel bridges. Experimental tests of road and railway bridges under normal service loads are presented. Displacements, strains, vibration velocities, frequencies, accelerations, vibration damping in soil-steel bridges are analysed in detail. Besides, the dynamic amplification factors are also shown as the one of the most important element for designing the bridges. The load rating procedure of soil-steel bridges is presented. Durability tests of the backfill corrosivity are also described including the soil resistivity testing (Wenner method) and acidity (pH value) and moisture content of backfill. Statistical interrelation between soil resistivity and pH, moisture content was performed. American, Australian and Canadian standards concerning the estimation of soil-steel bridge durability were verified and confronted with the conditions of the minimum durability as for culverts (40 years) and the service life expected as for typical bridges (100 years). At the end of the chapter, the deformation of the ground caused by the traffic live loads is shown including the damping in soil medium. In addition, the mathematic model of soil deformation is also given.