| Description |
Expanded Polystyrene (EPS) geofoam is a superlight weight material used in various geotechnical engineering applications. The goal of this study was to explore the use of EPS embankment to support railways and bridges without being overstressed during extreme events like earthquakes. Static and dynamic deflections that occur on an embankment along a rail line were measured by using numerical, laboratory and field techniques. A numerical method was used to measure static deflection whereas accelerometers were used in case of dynamic deflection. In the laboratory, large scale triaxial and large chamber tests were conducted to determine the resilient modulus of ballast. In the field, accelerometers were placed on sleepers of commuter and light rail line to collect the data for vertical deflection. Monotonic and cyclic triaxial tests, analytical and numerical methods were used to study bridge support embankments. The dynamics of EPS embankment for support of bridge system was studied and possible lateral restrained systems were developed for moderate to higher seismic excitations. Large chamber test is more suitable for the calculation of cyclic nonlinear secant modulus. EPS embankment performed well while considering vertical deflection. The combination of dead and earthquake load can be considered as the stress corresponding to 2 percent axial strain. The critical accelerations for sliding, sway and rocking were 0.6 g, 0.2 g and 0.3 g, respectively. Shear keys, embedment of embankment and cables are required for higher excitations. |
