A Case History of the Use of Geofoam for Bridge Approach Fills

A new bridge replaced the Route 85 Bridge over Normans Kill Creek in Albany, NY in 2001. The old bridge was a double span steel truss bridge with pile-supported abutments and a mid pier in the creek channel. The replacement is a single span concrete girder bridge and was constructed adjacent to the old bridge to minimize the extent of realignment of the roadway centerline. The soil stratigraphy along the creek bank consists of weak and compressible lacustrine deposits. During construction of the new bridge, the old bridge had to remain in operation. EPS geofoam was used as a lightweight substitute for soil to construct the approach fills for the new bridge to assure stability and minimize settlements. Extensometers and earth pressure cells were installed to monitor the performance of the approach fills. The roadway profile has been surveyed periodically to develop the settlement profile over time. In addition to improving stability and reducing settlements, the use of geofoam for the bridge approaches has resulted in additional benefits. The construction was quick and took place in winter. Lateral pressures against the abutments and wing walls are low. Results of the field monitoring are presented and compared with computer modeling of a representative section

On the Seismic Earth Pressure Reduction Against Retaining Structures Using Lightweight Geofoam Fill

A numerical analysis was carried out for a rigid retaining wall experiencing earthquake loading. The seismic forces acting on the wall was determined by simulating both sinusoidal load as well as the earthquake time history of an actual earthquake. At first considering that the backfill consists purely of sandy soils, the failure zone and the resulting earth pressure were calculated. After observing the failure zone of such backfill, the domain is substituted by lightweight Expanded Polystyrene (EPS) geofoam. The effect of replacing the sand with such lightweight materials on the developed seismic thrust is then examined. The results show that the use of the EPS geofoam as a replacement renders as much as 50% to 60% reduction of the seismic thrust

Capacity building in the engineering environment: the WFEO guidebook

The Standing Committee on Engineering Capacity Building of the World Federation of Engineering Organisations (WFEO) in October 2010 launched the first edition of a guidebook setting out its understanding of the challenges and complexities facing the engineering community regarding capacity and sustainability issues. The guidebook suggests approaches to the building of human resources and capability, and presents a collection of philosophies, programmes, initiatives and good practices collated from the experiences of a range of engineering organisations and engineering professionals

Análisis comparativo en losas de cimentación: losas aligeradas mediante bloques de EPS frente a losas macizas

The objective of this article is to confirm the different behavior of the traditional slab foundation against a lightened, making a comparative analysis, using the MEF, of the first solution with a lightened slab using expanded polystyrene (EPS) blocks, joining solid areas on pillars with grating beams. Therefore there are two top and bottom plates covering the EPS blocks. The results obtained allow assert ourselves that in situations of soft soils, with possible problems of settlements, the proposed solution has significant advantages by reducing them a percentage will vary depending on specific conditions. Besides this, it reduces significantly the differential settlements between supports, so this alternative has a more uniform behavior, as well as constructive advantages.<br><br>El objetivo del presente artículo es confirmar el distinto comportamiento que presenta la solución tradicional de losa maciza frente a una aligerada, haciendo un análisis comparativo, aplicando el M.E.F., de la primera solución con una losa aligerada empleando bloques de poliestireno expandido (EPS) como material aligerante, uniéndose las zonas macizas bajo pilares mediante nervios. Se mantienen, por tanto, dos placas superior e inferior alrededor de los bloques aligerantes de EPS. Los resultados obtenidos nos permiten afirmar que en situaciones de suelos blandos, con posibles problemas de asientos, la solución planteada presenta importantes ventajas, al disminuir éstos en un porcentaje que variará en función de las condiciones particulares. Además de esto, se reducen en gran medida los asientos diferenciales entre apoyos, por lo que la alternativa planteada presenta un comportamiento más uniforme, así como ventajas constructivas

An experimental study of the small strain response of sand

Fundamental behaviour of Ottawa sand, in the strain range of 1 x 10⁻² to 1 x 10⁻⁵, is investigated by direct measurement of deformations in a load controlled conventional triaxial system. Experiments are aimed at examining common concepts and previous experimental justifications for incremental elastic, elasto-plastic and particulate frameworks for characterizing sand behaviour. From fundamental interpretation of test data, an alternative stress-strain relationship is proposed for proportional loading with relative density represented as a separate parameter. Maximum Young's moduli evaluated from resonant column tests are found to be approximately equal to initial unloading moduli from conventional triaxial tests and initial moduli from virgin loading and subsequent reloadings are much less. Initial unloading moduli are relatively unaffected by the cycle of loading and deviator stress level from which unloading is initiated. The value of Young's modulus at a stress state Is not unique but depends on the stress path and strain history. Nonrecovered strain directions, at small strain, depend on stress direction as opposed to the generally accepted dependence on stress state at large strain. Proportional loading paths are uniquely related to linear strain increment directions and maintain parallel mean normal stress equipotentials in strain space. Energy density increments in two proportional loading paths having identical mean normal stress histories remain proportional. Parallel nonproportional loadings result in a unique strain increment direction, relatively independent of hydrostatic stress level, with linear stress ratio equipotentials in strain space. In small strain response, shear strains result mainly from shear stress increments and not from changes in stress ratio. Shear volume response is contractant for both an increasing and decreasing shear stress increment, whereas the sense of shear strain increment alternates with the sense of shear stress increment. When the sense of strain state is opposite to the sense of an applied stress increment, the resulting stress-strain response is softer than when both are of the same sense. Strain paths for compression side shear loading are identical to paths of extension side shear unloading and vice versa. More shear and volumetric strains develop on extension side shear loadings and the ratio of volumetric to shear strain is also higher as opposed to comparable compression side shear loadings. At higher stress ratio states, decreasing mean normal stress at constant shear and increasing stress ratio conditions; extension side volumetric strain responses are associated with contraction following initial swelling and prior to dilation. This contraction phase is not present on the compression side.Applied Science, Faculty ofCivil Engineering, Department ofGraduat