Figure - available from: Transportation Infrastructure Geotechnology
This content is subject to copyright. Terms and conditions apply.
Source publication
In an integral abutment bridge (IAB), the superstructure and the abutment are constructed monolithically at their junction without the presence of any bearing or expansion joint. This leads to a significant reduction in the maintenance cost of the bridge. However, integral connection at deck-abutment junction causes a significant change in the brid...
Similar publications
Over the last decade, there was a renewed interest on Integral Abutment Bridges (IABs), characterized by the absence of bearing supports and expansion joints, leading to reduced construction and maintenance cost over ordinary bridges. Due to monolithic connections between abutments and deck, complex Soil-Structure Interaction (SSI) phenomena tend t...
Citations
... It has been observed that many bridges in the United States, especially older ones constructed prior to the establishment of modern seismic regulations, are not equipped to withstand significant seismic forces. Even relatively minor seismic events have the potential to cause considerable damage to these structures [13][14][15][16]. Figure 1 illustrates the extent of damage to bridges caused by earthquakes. ...
... The vulnerability of bridges, as a critical component of the transportation network, has been emphasized by damages inflicted by such seismic events globally. Even though some of these earthquakes were relatively minor, their impact on bridge infrastructure has been profound [14,15,17,18]. The potential for bridge damage to cause substantial disruption to the transportation system and incur significant direct and indirect costs is well-documented. ...
In the realm of civil engineering and structural analysis, the seismic resilience of infrastructure remains a critical area of research. This study delineates the seismic response assessment of a reinforced concrete bridge situated in Sibu, Sarawak, through the lens of finite element analysis (FEA). Embracing the robust capabilities of FEA, a comprehensive model of the reinforced concrete bridge is developed, enabling the simulation of its response to seismic forces. Notably, the seismic loading conditions are derived from the Chi-Chi earthquake time history data, a choice informed by the earthquake's significance in seismic research and the richness of its data, rather than its direct seismic comparability to Sarawak. The FEA, conducted using the Abaqus/CAE 6.14 software, meticulously models the bridge, incorporating varying peak ground acceleration (PGA) values of 0.10g, 0.20g, 0.50g, and 1.00g. Key structural response parameters, including maximum principal stress, acceleration, and displacement, are systematically extracted and analyzed. This meticulous approach uncovers the material resilience of the bridge, even under extreme seismic forces exemplified by a PGA of 1.00g. The integrative analysis, encompassing both static pushover and dynamic time history analyses, elucidates the structural integrity and performance of the reinforced concrete bridge in the face of seismic challenges. The findings not only contribute to the understanding of seismic impacts on reinforced concrete bridges but also pave the way for enhancing seismic design and resilience strategies in structural engineering.
... seismic actions. 6 Indeed, the mandate for the revision of the structural Eurocodes, specifically indicated seismic design of IABs among the necessary extension of scope. ...
Integral abutment bridges (IABs) are becoming the solution of choice in the low to mid‐length ranges because of their low cost compared with traditional solutions and their good performance under seismic actions. The main drawback of these bridges is the need to consider soil‐structure interaction to assess their performance, a problem that is more pronounced for actions implying horizontal deck movements, such as temperature or the specific focus of this paper, that is, seismic action. In IAB design, simplified models are often used, where soil‐structure interaction is modeled by means of beams on non‐linear Winkler springs for the evaluation of seismic behavior. This paper, starting from an existing non‐linear dynamic model (NLDM) that describes IABs longitudinal seismic response, derives two equivalent static models: one non‐linear and the other linear, for displacement‐ or force‐based design respectively. A parametric study is carried out to assess the static models performance in terms of the main design internal actions versus the NLDM. Finally, the assessed model errors are discussed in the context of partial factors safety format.
... However, the widespread construction of IABs is currently limited by the lack of internationally accepted mechanistic models and coherent design guidelines, and by code restrictions such as the maximum span length (60 m) and skew angle (30 • ) [6][7][8][9]). These limitations are mainly due to the uncertainty associated with the way the backfill interacts with the (integral) abutment and the deck in different loading scenarios during the service life, such as seasonal thermal loadings (e.g., [10][11][12][13]), daily traffic loading (e.g., [14][15][16]and seismic loading (e.g., [17][18][19][20]). The loading from thermal actions on integral bridges is comparable in magnitude to that caused by live loads such as daily traffic loading (e.g., [10,11,21]). ...
Integral Abutment Bridges (IABs) are increasingly popular due to their reduced maintenance cost compared to traditional bridges with expansion joints. However, the widespread construction of IABs is currently limited by design code prescriptions resulting from the significant uncertainties associated with how the backfill interacts with the (integral) abutment and the deck. Under cycles of seasonal thermal loading, the backfill properties change, affecting the distribution of lateral earth pressures acting on the abutment walls. Moreover, the stiffness of the abutment can significantly influence the soil-structure interaction (SSI) in IABs. This research work investigates the effect of abutment stiffness (flexural rigidity) on soil-structure interaction in IABs under seasonal thermal loading through experimental analyses and numerical modelling. To better understand this mechanism and reliably assess the performance of IABs within their life cycle, a 1 g small-scale instrumented physical model was built to simulate the backfill under accelerated seasonal expansion and contraction of the bridge deck. The experimental results were modelled numerically in PLAXIS and ABAQUS to assess the sensitivity to different flexural stiffnesses of the abutment and discuss suitable options for modelling such SSI systems through finite elements either using a geotechnical-oriented or a structural-oriented software package. It was found that flexible IABs can be more suitable for controlling earth pressure built-up within the early lifecycle of the soil-structure systems. The simplified numerical models can provide a first-order prediction of pressure distributions in the small-scale 1-g rig. This preliminary dataset informs necessary larger-scale experiments to assess the scaling and feasibility of 1-g tests.
... Integral abutment bridges (IABs) can relieve durability problems, reduce maintenance and repair costs, and improve driving comfort by eliminating expansion, deck, and bearings [1][2][3][4][5][6][7][8][9]. Furthermore, IABs can exhibit satisfactory seismic performance in earthquakes due to the increased redundancy of the monolithic connection between the superstructure and substructure, higher damping resulting from cyclic soil-pile-structure interaction, smaller displacement demand, and the elimination of girder unseating potential [10][11][12][13][14][15][16]. Therefore, IABs are promising design techniques in earthquake-prone areas [17]. ...
A R T I C L E I N F O Keywords: Integral abutment bridge Pile with pre-hole seismic isolation system Sand-pile interaction Filling material Pseudo-static low cycle test Finite element model P-y curve A B S T R A C T Under seismic actions, reinforced concrete (RC) piles are considered the most vulnerable components of integral abutment bridges (IABs). This paper investigates the mechanical behavior of the pile with pre-hole seismic isolation system through pseudo-static low cycle tests and numerical analyses on scaled specimens with various filling materials. The ultimate goal of this technical solution is to improve the seismic performance of IABs. The experimental results proved that the pile specimens with pre-hole seismic isolation system exhibit higher energy dissipation than those without pre-hole. The equivalent viscous damping is 17.1 ~ 49.3 % higher when the filling is rubber and 3 ~ 12 % higher using foam. The influence of the pre-hole diameter and soil deformation is also significant. When the pre-hole diameter is large enough, the horizontal displacement of the pile specimen is entirely absorbed by the rubber particles. Nevertheless, the pre-hole seismic isolation system does not significantly influence the failure mode, skeleton curve, yield load and bearing capacity. Finite element models (FEMs) were implemented in ABAQUS and calibrated using the experimental results. The FEMs allowed extrapolating the experimental outcomes under different geometrical and mechanical configurations, considering the sand-pile interaction with various filling materials (rubber particles and foam), and pre-hole sizes. The numerical results showed that the subgrade modulus and the ultimate soil resistance decrease when the pile has a pre-hole seismic isolation system. Therefore, the lateral deformation of a pile with pre-hole seismic isolation system can be estimated by multiplying the subgrade modulus used for the pile by a specific reduction factor dependent on the pre-hole geometry and the mechanical parameters of the filling material. The paper proposes and discusses a novel definition of the p-y curves for predicting the response of the pile with pre-hole seismic isolation system modified from classical p-y curves.
... The use of IABs is encouraged by recent studies demonstrating that several such bridges subjected to strong ground motion in California and New Zealand showed a better performance than conventional construction types. 1,2 The country with the largest number of IABs is by far the USA, with tens of thousands of structures built from the 1930s to date. 3 Since the 1950s, this structural typology has been largely employed also in Europe, [4][5][6][7] where the construction practices differed somewhat from those adopted in the USA. 8,9 More recently, IABs have been realized in many other countries, e.g. in Japan, 10,11 and Australia. ...
The seismic performance of integral abutment bridges (IABs) is affected by the interaction with the surrounding soil, and specifically by the development of interaction forces in the embankment‐abutment and soil‐piles systems. In principle, these effects could be evaluated by means of highly demanding numerical computations that, however, can be carried out only for detailed studies of specific cases. By contrast, a low‐demanding analysis method is needed for a design‐oriented assessment of the longitudinal seismic performance of IABs. To this purpose, the present paper describes a design technique in which the frequency‐ and amplitude‐dependency of the soil‐structure interaction is modelled in a simplified manner. Specifically, the method consists of a time‐domain analysis of a simplified soil‐bridge model, in which soil‐structure interaction is simulated by means of distributed nonlinear springs connecting a free‐field ground response analysis model to the structural system. The results of this simplified method are validated against the results of advanced numerical analyses, considering different seismic scenarios. In its present state of development, the proposed simplified nonlinear model can be used for an efficient evaluation of the longitudinal response of straight IABs and can constitute a starting point for a prospective generalisation to three‐dimensional response.
... Additionally, the abutment is also subjected to permanent deformation from the deck due to the creep, shrinkage, and prestressing (Clayton, Xu, & Bloodworth, 2006). All of these factors constitute the complexity of adopting the IAB structure in practice (Dhar & Dasgupta, 2019;Mitoulis, 2020). ...
Integral abutment bridges (IAB), especially the short to medium-span IABs, have become more popular throughout the years in Australia as well as globally. IABs have advantages over traditional bridges in terms of their construction and maintenance costs due to the elimination of expansion joints. However, the thermal expansion can develop significantly larger earth pressure behind the abutment, thus leading to excessive forces (i.e. moment and shear force) to the foundation, which are not considered during the design process and can cause cracking and failures, eventually. It is observed from the field monitoring of IABs that the earth pressure model used to estimate the pressure distribution is not adequate to capture possible variations. Further, the performance of IABs highly depends on the complex interaction of abutment-backfill and soil-foundation and the time-dependent and cyclic behaviour of backfill and foundation soils. In this paper, nonlinear finite element model of an IAB considering the time-dependent effects of materials is presented to simulate long-term responses due to thermal loading. The developed IAB model results are validated using field monitoring data and parametric study is performed including the geometry of IAB, thermal loading, and soil properties. The results are used to investigate the functional relationship between input parameters and long-term responses which are further utilised to develop a new earth pressure distribution model for the design and performance assessment of IABs.
... This can be achieved by better diagnosis (i.e. developing know-how on the problem to reduce epistemic uncertainty) and feeding research findings from laboratory experiments, modelling and fieldmonitoring campaigns into national and international design code development (Dhar and Dasgupta, 2019). In support of this and similar goals, the UK Collaboratorium for Research on Infrastructure and Cities (UKCRIC, 2022) has recently created a suite of world-leading laboratory facilities combining multidisciplinary research teams with systems thinking and practice approaches to enhance the value of, and de-risk investments in, infrastructure and urban system interventions. ...
This study focuses on the investigation of the factors that have limited, so far, the development of a consistent design and assessment approach for integral bridges (IBs). This paper presents a review of previous research and current design practices for IBs, followed by an overview of monitoring studies in the laboratory and in the field. As part of the UK Collaboratorium for Research on Infrastructure and Cities–Priming Laboratory EXperiments on Infrastructure and Urban Systems experimental campaign, a small-scale 1 g physical experiment is described. The test aimed to simulate the soil–structure interaction arising from seasonal expansion and contraction of the bridge deck and assess the performance of different monitoring techniques. Pressure cells were used to measure the lateral stresses behind the abutment wall, particle image velocimetry was employed to monitor the soil behaviour behind the abutment and linear variable differential transformers were used to monitor the backfill surface movements. By combining the data from these instruments, a preliminary assessment of the soil–structure interaction behaviour of the idealised integral abutment under seasonal thermal loading has been obtained. These monitoring methods and the associated understanding of IB behaviour gained from the tests provide definitive evidence for the development of monitoring systems for larger-scale physical tests and field monitoring systems for IBs.
... Reducing or removing uncertainties/barriers and improving the functionality of IBs, Accepted manuscript doi: 10.1680/jsmic.21.00020 11 throughout their design, construction, operation and maintenance phases, provide a means of reducing infrastructure costs and increasing their value. This can be achieved by better diagnosis (i.e., developing knowhow on the problem to reduce epistemic uncertainty) and feeding research findings from laboratory experiments, modelling and field-monitoring campaigns into national and international design code development (Dhar and Dasgupta 2019). ...
This study focuses on the investigation of the factors that have limited, so far, the development of a consistent design and assessment approach for integral bridges (IBs). This paper presents review of previous research and current design practices for IBs, followed by an overview of monitoring studies in the laboratory and in the field. As part of the UKCRIC PLEXUS experimental campaign, a small-scale 1g physical experiment is described. The test aimed to simulate the soil-structure interaction arising from seasonal expansion and contraction of the bridge deck and assess the performance of different monitoring techniques. Pressure cells were used to measure the lateral stresses behind the abutment wall, Particle Image Velocimetry was employed to monitor the soil behaviour behind the abutment and Linear Variable Differential Transformers were used to monitor the backfill surface movements. By combining the data from these instruments, a preliminary assessment of the soil-structure interaction behaviour of the idealised integral abutment under seasonal thermal loading has been obtained. These monitoring methods and the associated understanding of IBs’ behaviour gained from the tests provide definitive evidence for the development of monitoring systems for larger-scale physical tests and field monitoring systems for IBs.
... To this end, there is a clear need for developing know-how as to IAB-soil interaction to feed relevant research findings into design code development. 24 Some national codes and guidelines offer provisions for the static design of IABs. [25][26][27] On the other hand, in earthquake-prone areas in Europe such as Italy and Greece, the use of IABs is limited mainly due to a lack of explicit design guidelines for seismic loads (e.g., no explicit clauses are provided in the Eurocodes), but also due to a shortage in dependable mechanistic models to predict their response. ...
In recent years there has been renewed interest on Integral Abutment Bridges (IABs), mainly due to their low construction and maintenance cost. Owing to the monolithic connection between deck and abutments, there is strong soil-structure interaction (SSI) between the bridge and the backfill due to both thermal action and earthquake shaking. Although some of the regions where IABs are adopted qualify as highly seismic, there is limited knowledge as to their dynamic behaviour and vulnerability under strong ground shaking. To develop a better understanding on the seismic behaviour of IABs, an extensive experimental campaign involving over 75 shaking table tests and 4,800 time histories of recorded data, was carried out at EQUALS Laboratory, University of Bristol, under the auspices of EU-sponsored SERA project (Seismology and Earthquake Engineering Research Infrastructure Alliance for Europe). The tests were conducted on a 5m-long shear stack mounted on a 3m x 3m 6DOF earthquake simulator, focusing on interaction effects between a scaled bridge model, abutments, foundation piles, and backfill soil. The study aims at (i) developing new scaling procedures for physical modelling of IABs, (ii) investigating experimentally the potential benefits of adding compressible inclusions between the abutment and the backfill, and (iii) exploring the influence of different types of connection between the abutment and the pile foundation. Results indicate that the compressible inclusion reduces the accelerations on the bridge deck and the settlements in the backfill, while disconnecting piles from the cap decreases bending near the pile head.
... To this end, there is a clear need for developing know-how as to IAB-soil interaction to feed relevant research findings into design code development. 24 Some national codes and guidelines offer provisions for the static design of IABs. [25][26][27] On the other hand, in earthquake-prone areas in Europe such as Italy and Greece, the use of IABs is limited mainly due to a lack of explicit design guidelines for seismic loads (e.g., no explicit clauses are provided in the Eurocodes), but also due to a shortage in dependable mechanistic models to predict their response. ...
