Design of piled bridge abutments on soft clay for loading from lateral soil movements

Abstract

Piles supporting bridge abutments on soft clay may be loaded laterally from horizontal soil movements generated by the approach embankment. The design of piles loaded by lateral soil movements is problematic in that existing design approaches are generally inconsistent or show poor correlation with available data. New empirical design charts are presented to allow an assessment of maximum pile bending moment and pile head deflection based on the relative soil-pile stiffness and current loading level. A new analytical approach is also developed on the basis of a simple deformation mechanism. The method accounts for the main features of the problem through an approximate representation of the embankment-soil-pile interaction, and is shown to compare favourably with centrifuge model test data. Recommendations for the design of pile groups for loading from lateral soil movements are also given. Les mouvements horizontaux du sol crées par le remblai sont susceptibles d'engendrer des contraintes latérales dans les pieux supportant les culées de ponts construites sur des argiles molles. La conception des pieux chargés latéralement par les mouvements due sol, pose des problèmes puisque les approches conceptuelles existantes sont générallement contradictoires et présentent une mauvaise corrélation avec les données disponibles. L'article présente de nouveaux abaques empiriques permettant d'accéder, à partir de la raideur relative sol-pieu et du niveau de chargement courant, au moment de flexion maximal du pieu et au déplacement en tête de pieu. Une nouvelle approche analytique, fondée sur un mécanisme de déformation simple, est également développée. La méthode rend compte des principales caractéristiques du problème grâce à une représentation approchée des interactions remblai-sol-pieu. La comparaison avec les données issues de l'essai de centrifugation semble bonne. L'article propose également des recommandations pour la conception de groupes de pieux soumis à un chargement par mouvements latéraux du sol.

Bridge distress caused by approach embankment settlement

“…To test this hypothesis, the movements of the pile caps at pier E and abutment F were evaluated using a very simple empirical method. 3 The method involves a design chart, developed from centrifuge model data and field observations, that relates the non-dimensional pile cap deflection˜y q to the relative soil-pile stiffness K R , where …”

“…3L (where L is the pile length above the base of the soft layer) when horizontal movement is not restrained (pier E) or L when rotation is prevented by a rigid cap (abutment F). 3 The method takes no specific account of factors such as pile spacing, group size, group configuration or embankment shape, although a broad range of pile abutment configurations are represented in the dataset used to develop the design chart.…”

“…Unfortunately, piles constructed through soft soil may be subject to lateral loads and movements as a result of time-dependent deformation of the soil underlying the approach embankments. 3,4 Design guidance tends to focus on movements of the bridge foundations, with less attention being paid to foundation conditions beneath the approach embankments. Differential settlement between a bridge abutment and approach embankment can be damaging to the road pavement, although such damage is easier to remedy than damage to the bridge superstructure.…”

Experimental study on bearing characteristc of Passive pile under soil lateral settlement

“…For the reason of high bearing capacity,low cost,high quality piling,et.al.pipe pile has been wildly applied in soft ground engineering.However,the lateral settlement for load on the ground,tunnel excavation and piling,the pile bears lateral positive load which has been entitled positive pile by De Beer [1].There are many analysis method for passive pile-soil interaction,such as experience method,displacement method and soil pressure method [2,3].The bearing characteristic of pile foundation for lateral displacement of soil had been studied by Franx [4].By model test, large passive soil pressure which leads to unstability of pile has been founded by Franx. Soil arching effect has been founded and validated by K.Terzaghi [5].Moreover,Simplified calculation model for bearing capacity of passive pile has been developed by Yan Reng-jue and Li Zhong-cheng [6] 。 In this paper, to reveale relationship of lateral displacement of soil and vertical bearing capacity of pile,a model test had been conducted by changing lateral displacement of soil and load position.…”

Piled embankment to prevent damage to pipe buried in soft grounds undergoing lateral flow

“…Over the past four decades, studies on lateral movement of abutment installed on soft ground have been extensively done (Broms and Ingelson 1971;Stewart, Jewell, and Randolph 1994;Goh, Teh, and Wong 1997;Poulos and Chen 1997;Helwany, Wu, and Froessl 2003;Lemnitzer et al 2009;Cubrinovski et al 2012;Hong, Hong, and Kang 2016). However, there are few scholars who work on buried pipe in soft soils undergoing lateral flow (Hong 2005;Hong and Lee 2009).…”