A laboratory study of the development of earth pressure behind integral bridge abutments

Abstract

(2006) A laboratory study of the development of earth pressure behind integral bridge abutments. Geotechnique, 56 (8). pp. 561-571 Permanent WRAP URL: http://wrap.warwick.ac.uk/85236 Copyright and reuse:The Warwick Research Archive Portal (WRAP) makes this work by researchers of the University of Warwick available open access under the following conditions. Copyright © and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable the material made available in WRAP has been checked for eligibility before being made available.Copies of full items can be used for personal research or study, educational, or not-for-profit purposes without prior permission or charge. Provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. A conventional bridge abutment utilises bearings to support the bridge deck, and expansion joints to allow it to slide as temperature changes occur. But experience has shown that expansion joints often leak, leading to deterioration of underlying structural elements, and are expensive to maintain and replace. As a result integral abutments, which are fully fixed with respect to the bridge deck, are increasingly being recommended. However, there is uncertainty about the magnitude of the earth pressures that they should be required to support. Available evidence from model tests and from field instrumentation does not provide a basis upon which to predict either the circumstances under which thermal cycling will lead to significant increases in earth pressure, or the levels to which they might rise. This paper reports the result of laboratory tests on natural clay samples, on pluviated sand specimens, and on glass ballotini, all of which have been subjected to the stress paths and levels of cyclic straining that a typical integral bridge abutment might impose on its retained soil. The results show that whereas the natural clay and the glass ballotini showed no lateral stress accumulation, regardless of strain levels and stress excursions, the pluviated sand specimens experienced systematic increases in lateral stress for almost all cyclic strain levels, eventually reaching states of stress at, or close to, both active and passive. The underlying mechanisms of stress increase are explored, and it is concluded that particle shape is an important factor in determining the response of soil to this special type of loading.KEYWORDS: clays; laboratory tests; repeated loading; sands; stiffness; stress paths Un contrefort de pont conventionnel utilise des appuis pour soutenir le tablier de pont et des joints de dilatation pour donner à la structure une flexibilité de glissement en fonction des changements de température. Cependant l'expérience montre que ces joints sont souvent sujets aux fuites et provoquent une détérioration des éléments structurels sous-jacents. Ils sont ...

Discrete Element Analysis of the Response of Granular Materials During Cyclic Loading

“…These assemblies of steel spheres are an ideal material and are considered here to be an analogue soil. For example, this material has a geometry that is substantially simpler than the geometry of real sands (the importance of geometry on cyclic soil response is considered by Clayton et al, 2006), and this material will not exhibit the degree of particle abrasion under cyclic loading observed by Festag and Katzenbach (2001). The use of such an ideal material is in this study is motivated by a desire to directly compare simulations performed using the DEM model with physical test data for validation purposes.…”

“…Cyclic loads of relatively high frequency are felt during earthquakes, however lower frequency repeated loadings are also important. Such loading scenarios include the foundations to road pavements (e.g., Lekarp et al, 2000), wind turbine foundations, foundations to reciprocating machines, soil adjacent to integral bridge abutments (e.g., Clayton et al, 2006), and soil in dams where the reservoir level ‰uctu-ates. Janbu and Seneset (1981) proposed that observed time-dependant settlements of structures on high permeability soils may be due to combined eŠects of cumulative displacements under cyclic loading and creep.…”

A new type of integral bridge comprising geosynthetic-reinforced soil walls. Tatsuoka, F., Hirakawa, D., Nojiri, M., Aizawa, H., Nishikiori, H., Soma, R., Tateyama, M. and Watanabe, K. (2009). Geosynthetics International, IS Kyushu 2007 Special Issue, 16, No. 4, 301–326.

“…England and Dunstan (1994) also evaluated this intrinsic stress-strain property of sand to understand the mechanism of the buildup of the earth pressure by cyclic loading. The discussers (Clayton et al 2006;Xu et al 2007a) also performed stress path tests using a triaxial apparatus on a solid cylindrical specimen. The discussers call the 'cyclic strain-hardening effect' the 'grain-interlocking mechanism'.…”

“…Although the particles of SLB sand are slightly smaller than those of the LB sand (fraction B) used by the discussers, both are similarly rather round (Figures 55b and 55c). Clayton et al (2006) and Xu et al (2007a) evaluated the effect of particle shape in stress path tests and found that, by cyclic loading with a fixed amplitude of lateral strain, the peak lateral stress in the respective cycles increases considerably, approaching the passive earth pressure for LB sand (fraction B), where this is not the case for a spherical uniformly graded granular material, glass ballotini. Although LB sand (fraction B) and SLB sand are not spherical, they are much more round than Toyoura sand ( Figure 55 and Table 2).…”

“…Cyclic strain-hardening effect in soil element tests Clayton et al (2006) and Xu et al (2007a) evaluated the grain-interlocking mechanism (i.e. the cyclic strainhardening effect) by performing stress-path test utilizing an automated triaxial cyclic loading system in which the specimens were subjected to a constant vertical stress and a constant amplitude of cyclic horizontal strain.…”