Behavior of a Stiff Clay behind Embedded Integral Abutments

Xu, Mingwei; Bloodworth, Alan G.; Clayton, C. R. I.

doi:10.1061/(asce)1090-0241(2007)133:6(721)

Cited by 18 publications

(5 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…post-earthquake, mean value of the earth pressures was 190 kPa for the conventional and 47 kPa for the isolated abutment, whilst the distribution of the latter was linear along the height of the abutment. 19 A significant reduction in the settlements of the backfill soil was also observed for the isolated abutment. For the displacements of the abutment during the bridge service, the backfill soil exhibited a maximum swelling of 15mm, whilst the conventional one exhibited a settlement of 85 mm, followed by a maximum swelling of 123 mm.…”

Section: Discussionmentioning

confidence: 80%

“…The cyclic movement of the abutment causes significant horizontal stress variations behind the abutments, build-up of the earth pressures [12][13][14][15] and nonlinear deflections of the backfill [16]. The significance of the earth pressures behind integral abutments and their evolution is further discussed by Barker et al [17], Springman et al [13] and other researchers [18,19].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Extending the application of integral frame abutment bridges in earthquake‐prone areas by using novel isolators of recycled materials

Mitoulis

Palaiochorinou

Georgiadis

et al. 2016

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

Integral Abutment Bridges (IABs) are jointless structures without bearings or expansion joints, which require minimum or zero maintenance. The barrier to the application of longspan IABs is the interaction of the abutment with the backfill soil during the thermal expansion and contraction of the bridge deck, i.e. serviceability, or when the bridge is subjected to dynamic loads, such as earthquakes. The interaction of the bridge with the backfill leads to settlements and ratcheting of the soil behind the abutment and, as a result, the soil pressures acting on the abutment build-up in the long-term. This paper provides a solution for the aforementioned challenges, by introducing a novel isolator that is a compressible inclusion (CI) of reused tyre derived aggregates (TDA) placed between the bridge abutment and the backfill. The compressibility of typical tyre derived aggregates was measured by laboratory tests and the compressible inclusion was designed accordingly. The CI was then applied to a typical integral frame abutment model, which was subjected to static and dynamic loads representing in-service and seismic loads correspondingly. The response of both the conventional and the isolated abutment was assessed based on the settlements of the backfill, the soil pressures and the actions of the abutment. The study of the isolated abutment showed that the achieved decoupling of the abutment from the backfill soil results in significant reductions of the settlements of the backfill and of the pressures acting on the abutment. Hence, the proposed research can be of use for extending the length limits of integral frame bridges subjected to earthquake excitations.

show abstract

Section: Discussionmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Extending the application of integral frame abutment bridges in earthquake‐prone areas by using novel isolators of recycled materials

Mitoulis

Palaiochorinou

Georgiadis

et al. 2016

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

show abstract

“…settlements/heaving [8] [17] [18] [19] behind the abutment and in many cases pavement cracks [20]. The movements of integral bridge ends are partly uni-directional, due to the permanent loads of concrete creep and shrinkage, and partly cyclic, due to variable loads, mainly temperature [15] [21]. There is experimental evidence that cyclic movements of the abutments may result in a considerable increase of the earth pressure, an effect known as strain ratcheting [19].…”

Section: Introductionmentioning

confidence: 99%

“…wall, footing approach slab e.t.c., and geotechnical components, e.g. backfill synthesis and use of reinforcements or not, there is also a huge dispersion in the literature [22]: IAB applications in the USA tend to use stub-type abutments with metallic piles [2] in loose soil relying on the flexibility and fatigue resistance of the piles, which in some cases are designed to yield [21] [23] whilst the European IABs rely on the flexibility of reinforced concrete sections, e.g. the abutment wall, thus using full-height [24] abutments or slide-on-backfill abutments.…”

Section: Introductionmentioning

confidence: 99%

Numerical modelling of integral abutment bridges under seasonal thermal cycles

Caristo¹,

Barnes²,

Mitoulis

2018

Proceedings of the Institution of Civil Engineers - Bridge Engi

View full text Add to dashboard Cite

The interest in Integral Abutment Bridges (IABs) from the industry has increased in recent years. IABs are robust bridges without joints and bearings hence they are durable and virtually maintenance-free; moreover, the resulting cost-saving associated with their construction is significant, a fact that makes IABs appealing to Agencies, Contractors and Consultants. However, their use in long-span bridges is limited by the complex Soil-Structure Interaction (SSI) which is developed between the structure and the backfill soil. Thermal movements, horizontal loads and dynamic actions are transferred directly to the backfill soil, leading to settlements, ratcheting effects and high earth pressures, hence deteriorating the serviceability of the structure and leading to poor driving conditions for the end-users. The longer the integral bridge the greater the challenge, as movements are increased and so are the aforementioned SSI phenomena. This is an acknowledged gap in IAB design philosophy and even though many solutions have been proposed in the international literature, the emphasis is placed on the understanding of the mechanisms developed within the soil, rather than on the efficient design of the involved components. This is the gap that this research fills. This paper provides an extended review of the techniques used in the international literature and in practice to alleviate the interaction between the bridge abutment and the backfill. Subsequently, the performance of an innovative isolation system for IABs using recycled tyres as a compressible inclusion is studied using detailed numerical models of a representative three span IAB. The inclusion decouples the response of the abutments and the backfill soil under static and dynamic loads. Regarding the methodology followed for assessing the performance of the IAB with the TDA isolator, initially, a conventional IAB is subjected to realistic temperature time histories and amplitudes essentially providing an envelope of the thermal cycles for 120 years of the bridge service and then a second IAB, isolated from the backfill, is subjected to the same loading. The two bridges, i.e. conventional and isolated, are then analysed for different initial restraint conditions, in order to determine the effect of initial temperature on the development of pressures behind the abutment walls. The comparison of the responses showed that the proposed isolation scheme is an effective and sustainable method to isolate the structure from the backfill soil, reducing the pressures experienced by the abutments and the residual vertical displacements of the backfill soil. The proposed research can be of use for extending the length limits of integral abutment bridges, delivering in this way long lasting and more sustainable infrastructure for future highways.

show abstract

“…To investigate the intrinsic behavior of soil behind integral abutments we have carried out laboratory stress path testing at the University of Southampton to study the development of earth pressure in granular materials behind frame integral abutments (Xu et al 2007a), and in natural stiff clay behind embedded integral abutments (Xu et al 2007b). Soil element tests were performed utilizing an automated triaxial cyclic loading system, which was developed based on a Bishop & Wesley apparatus.…”

mentioning

confidence: 99%