70 results found
Ramos-Moreno C, Ruiz-Teran AM, Stafford PJ, 2020, Guidance for footbridge design: a new simplified method for the accurate evaluation of the structural response in serviceability conditions, Advances in Bridge Engineering, Vol: 1, Pages: 1-21, ISSN: 2662-5407
This paper proposes a simplified hand-calculation methodology that permits a fast response assessment (both in vertical and lateral direction) under different pedestrian scenarios. This simplified method has the same accuracy than that of very sophisticated numerical nonlinear finite element models including pedestrian inter-variability, interaction among pedestrians in flows, and pedestrian-structure interaction. The method can capture the effects of pedestrian loads in and out of resonance. This methodology is based on a new, and experimentally contrasted, stochastic pedestrian load model derived by the authors implementing a multi-disciplinary state-of-the-art research, and on a large set of sophisticated finite element analyses.There is a significant gap in the literature available for bridge designers. Some current codes do not indicate how the performance for serviceability limit-states should be assessed, in particular for lateral direction. Others define methods that are not based on the latest research in this field and that require the use of dynamic structural analysis software. A very sophisticated load model, such as that described above, and recently proposed by the authors, may not be accessible for most of the design offices, due to time and software constraints. However, an accurate assessment of the serviceability limit state of vibrations during the design stages is paramount. This paper aims to provide designers with an additional simple tool for both preliminary and detailed design for the most typical structural configurations.First, the paper presents the methodology, followed by an evaluation of the impact of its simplifications on the response appraisal. Second, the paper evaluates the validity of the methodology by comparing responses predicted by the method to those experimentally measured at real footbridges. Finally, the paper includes a parametric analysis defining the maximum accelerations expected from pedestrian streams crossing mult
Garcia-Troncoso N, Ruiz-Teran A, Stafford PJ, 2020, Attenuation of pedestrian-induced vibrations in girder footbridges using tuned-mass dampers, Advances in Bridge Engineering, Vol: 1, Pages: 1-26, ISSN: 2662-5407
This article presents a numerical assessment of pedestrian-induced vibrations for a wide range of girder footbridges before and after the installation of tuned-mass dampers (TMD). Realistic pedestrian loads are defined using a stochastic model that represents the key characteristics of pedestrians and their intra- and inter-subject variability with the aim of ensuring an accurate estimation of the dynamic response. A comprehensive set of numerical analyses have been performed considering different cross sections, structural materials, span lengths (up to 100 m), and pedestrian flows. The optimal TMD characteristics, number and location, required to reduce the accelerations, down to a level that fulfils serviceability criteria, are identified. Design recommendations for girder footbridges implementing damping devices at the design stage are also included.
Xie H-B, Ruiz-Teran AM, 2020, Editorial, PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-BRIDGE ENGINEERING, Vol: 173, Pages: 121-122, ISSN: 1478-4637
Pring B, Ruiz-Teran AM, 2020, Modelling traffic action in high speed railway bridges, Proceedings of the Institution of Civil Engineers - Bridge Engineering, Vol: 173, Pages: 123-142, ISSN: 1478-4637
There are a significant variety of approaches taken by researchers when considering the response due to traffic in high speed railway (HSR) bridges. This paper will focus on the comparison between methods employed by different authors for the structural models developed for the bridge, the load models for the high-speed trains, and the interaction between the train vehicles and the bridge. The structural bridge models range from simple beam models to complex 3D solid models, with important implications interms of the ability of the models to predict realistic responses, as well as in terms of the appropriateness for design purposes considering the computational requirements. The load models vary from simple moving loads to a full vehicle moving system (with its own masses, stiffness, dampers, and contacts). For the latter approach, the interaction between the vehicle and the bridge becomes important. The major models in literature are identified and compared herein. The aim of this paper is to compile these different approaches and compare the different available methods, in order to enable a clearer judgement when setting the corresponding models for design purposes, as well as to provide a deeper understanding about some of the key definitions within the HSR bridge models.
Vazquez VF, Hidalgo ME, Garcia-Hoz AM, et al., 2020, Tire/road noise, texture, and vertical accelerations: Surface assessment of an urban road, APPLIED ACOUSTICS, Vol: 160, ISSN: 0003-682X
Xu B, Bompa DV, Elghazouli AY, et al., 2020, Numerical assessment of reinforced concrete members incorporating recycled rubber materials, Engineering Structures, Vol: 204, ISSN: 0141-0296
This paper is concerned with the inelastic behaviour of reinforced concrete beam-column members incorporating rubber from recycled tyres. Detailed three-dimensional nonlinear numerical simulations and parametric assessmentsare carried out using finite element analysis in conjunction with concrete damage plasticity models. Validationsof the adopted nonlinear finite element procedures arecarried out against experimental results from a series of tests involvingconventional and rubberised concrete flexural members and varying levels of axial load. The influence of key parameters, such as the concrete strength, rubber content, reinforcement ratio and level of axial load, on the performance of such members, is then examined in detail.Based on the results, analytical models are proposed for predicting the strength interaction as well as the ductility characteristicsof rubberised reinforced concrete members. The findings permit the development ofdesignexpressionsfor determiningthe ultimate rotation capacityof members,usinga rotation ductility parameter, or through a suggestedplastic hinge assessment procedure. Theproposedexpressionsare shown to offer reliable estimates of strength and ductilityof reinforced rubberised concrete members,whichare suitable for practical application and implementation in codified guidance.
Lyu Z, Malaga Chuquitaype C, Ruiz-Teran A, 2019, Design of timber-concrete composite (TCC) bridges with under-deck stay cables, Engineering Structures, Vol: 189, Pages: 589-604, ISSN: 0141-0296
Timber-concrete composite (TCC) bridges represent an attractive structural system due to the synergistic use of its wood and reinforced-concrete constituent components. However, their relatively large flexibility limits their applica- tion for larger spans. This paper presents an alternative solution for TCC bridges involving the implementation of post-tensioned under-deck tendons. Based on a series of design and numerical studies, the advantages of the newly proposed system for 30-m, 60-m and 90-m spans are evaluated. This paper shows that the incorporation of under-deck post-tensioning changes the critical limit states governing the design of TCC bridges, and allows for a significant increase in their slendernesses at medium and long spans. Timber’s shear-deformation contribution to the vertical deflection of TCC bridges is significant and should be accounted for, especially when the span/depth ratio l/h is less than 20. However, this additional deformation can be neglected when stay cables are implemented, especially for bridges with medium and long spans. In order to achieve a more efficient structure, it is proposed that shear connection with an efficiency coefficient, γ, greater than 0.8 be used. Finally, the best practical eccentricity of the under-deck tendons and the best location of the deviators are determined on the basis of parametric analyses.
Dong W, Stafford P, Ruiz-Teran A, 2019, Inverse form-finding for tensegrity structures, Computers and Structures, Vol: 215, Pages: 27-42, ISSN: 0045-7949
In this study we examine the topic of inverse form-finding, also referred to as topology finding, for tensegrity structures. Specifically, the problem addressed is given the specification of final nodal positions for a tensegrity, we seek to find appropriate connectivities, or topologies, that satisfy stability and connectivity constraints. Two new algorithms are presented in the paper. The first may be applied for generating prestress-stable tensegrity structures, while the second can be used to generate super-stable tensegrities. Numerical examples for both 2D and 3D tensegrities are provided to demonstrate that these new algorithms can produce desirable structures with nodal positions being the only prescribed piece of information. We also show that inverse form-finding of a specific Class k tensegrity can be formulated into a graph factorization problem. This is the first time that both the stability property and class can be specified among the few existing inverse form-finding methods. These new methods facilitate the design process in which a desired nodal geometry is prescribed, and viable structural configurations consistent with this geometry can be obtained.
Georgiadis K, Ruiz-Teran AM, Stafford PJ, 2019, Investigation of under-deck cable-stayed footbridges under dynamic pedestrian loading, Pages: 1655-1662
Under-deck cable-stayed (UDCS) footbridges are slender structures that promote the axial behaviour. This allows designers to take advantage of the entire sectional areas and reduce the required construction materials. Besides their high structural efficiency and sustainability, they also possess a number of other advantages such as multiple construction possibilities and strong aesthetic characteristics, therefore becoming an attractive solution in urban infrastructure. However, due to their slenderness, they are more prone to vibrations. Recent closures of footbridges of this typology, indicate that fundamental aspects of their structural response still remained unclear. This paper presents a set of example bridges built with this typology and a detailed investigation of a benchmark case under the dynamic action of pedestrians. Results show that, although ULS is satisfied using a very high deck slenderness (1/100), the SLS of vibrations is the critical design criterion that governs the slenderness of the deck (leading to values of 1/60).
Lyu Z, Malaga Chuquitaype C, Ruiz-Teran A, 2018, Dynamic response of an under-deck cable-stayed Timber-Concrete Composite bridge under a moving load, World Conference on Timber Engineering
Timber-Concrete Composite bridges have the potential to achieve significant levels of structural efficiency through the synergistic use of Engineering Wood Products (EWPs) and reinforced concrete. With the implementation of post-tensioned under-deck tendons, the range of application of TCC bridges can be extended to medium spans. However, little work has been done to date to study the dynamic response of these newly proposed bridges. In this paper, a set of FE models representing 60-m span structures are analysed to gain understanding on the dynamic response of post-tensioned under-deck TCC bridges. Two models with Euler and Timoshenko beam idealizations are considered in order to evaluate the significance of shear deformations on deflection, structural stresses and connector shear forces. Besides, an analytical model is formulated and compared against the numerical predictions. The results show that timber shear deformations should be considered in the design of post-tensioned under-deck TCC bridges. The dynamic characteristics of the bridge models were studied. The dynamic amplification caused by a moving point load on key response parameters such as deflection, stresses and connector shear forces is discussed. Also, a sensitivity study on the speed of moving load is conducted to investigate its influence on the bridge dynamic response.
Elghazouli AY, Bompa DV, Xu B, et al., 2018, Performance of rubberised reinforced concrete members under cyclicloading, Engineering Structures, Vol: 166, Pages: 526-545, ISSN: 0141-0296
This paper presents an experimental investigation into the cyclic behaviour of reinforced concrete members incorporating a significant proportion of recycled rubber particles as a replacement for mineral aggregates. Tests were carried out on thirteen large scale members of circular cross-section, with and without external confinement, and with different proportions of rubber content and axial loads. The specimens were subjected to inelastic lateral cyclic displacements and predefined levels of co-existing axial loading. After describing the testing arrangement and specimen details, the main results and observations are provided and discussed. The test results enable a direct comparative assessment of the key response characteristics of the specimens, with focus on stiffness properties and strength interaction, as well as ductility and energy dissipation. It is shown that rubberised reinforced concrete members can offer a good balance between bending capacity and ductility in comparison with conventional reinforced concrete members, particularly for low levels of axial loads. In the presence of relatively high axial loading and when a significant proportion of rubber content is used, external confinement such as through FRP sheets as employed in this study, can be adopted to recover the required capacity and to provide highly stable hysteretic response. The implications of the findings on the use of rubberised reinforced concrete members in practice, and procedures that can be used to determine the main design parameters, are also highlighted within the discussions.
Ramos-Moreno C, Ruiz-Teran AM, Stafford PJ, 2018, Serviceability response of a bench-mark cable-stayed footbridge: comparison of available methods, Footbridge 2017
In previous Footbridge Conferences, the focus of researchers has been on the representation of pedestrian actions (vertical and lateral) to design footbridges, on the proposal of methodologies for the analysis in service of these structures and on the description of the serviceability response of particular footbridges. Nonetheless, none of these research works have been focused on the magnitude of the serviceability response of footbridges according to its structural type.This paper characterises the response of footbridges with stayed cables as main structural type. Based on a compiled dataset of cable-stayed footbridges (developed for this research work), the paper presents the geometrical and structural characteristics of a footbridge that can be regarded as representative of this structural type. Considering the best methodologies available for the assessment of its response in vertical and lateral direction, the paper describes the magnitude of the serviceability performance of this bridge under a wide range of pedestrian scenarios. This description familiarises designers at early stages of their design with the order of magnitude of the serviceability response of cable-stayed footbridges with an arrangement similar to that commonly used for this structural type.
Elghazouli AY, Bompa DV, Xu B, et al., 2018, Performance of Rubberised Reinforced Concrete Members under Cyclic Loading, 16th European Conference on Earthquake Engineering (16ECEE)
Pring B, Ruiz-Teran AM, 2018, Investigating the Potential of Using High Performance Concrete in Precast High Speed Rail Bridges, Fib Symposium on High Tech Concrete - Where Technology and Engineering Meet, Publisher: SPRINGER INTERNATIONAL PUBLISHING AG, Pages: 2423-2431
Xu B, Bompa DV, Elghazouli AY, et al., 2017, Behaviour of rubberised concrete members in asymmetric shear tests, Construction and Building Materials, Vol: 159, Pages: 361-375, ISSN: 0950-0618
This paper deals with the experimental behaviour of rubberised concrete members subjected to asymmetric four-point shear loading. A detailed account of tests on 15 prismatic members using conventional concrete as well as rubberised concrete, with relatively high replacement ratios of both fine and coarse mineral aggregates with rubber particles, is given. The results enable direct assessment of strength and complete deformation characteristics including the post-peak response for ultimate behaviour governed both by shear and mixed-mode tensile-shear. After describing the material properties, mix designs and member details, the main observations from detailed measurements of the crack kinematics through a digital image correlation monitoring system, with focus on members developing shear-governed response, are reported. Complementary numerical studies are undertaken using nonlinear finite element procedures which are validated against tests developing shear-governed failures. In order to provide further insight into the key response characteristics, particularly those related to ultimate strength, a number of numerical sensitivity studies employing various constitutive parameters are also carried out. Moreover, comparative assessments in terms of shear resistance, toughness and force transfer across the cracked interfaces are performed and discussed. The detailed test measurements, coupled with the results obtained from the numerical simulations, permit the definition of expressions for representing the shear resistance as a function of the rubber content and concrete compressive strength.
Camara A, Vazquez VF, Ruiz-Teran AM, et al., 2017, Influence of the pavement surface on the vibrations induced by heavy traffic in road bridges, Canadian Journal of Civil Engineering, Vol: 44, Pages: 1099-1111, ISSN: 0315-1468
The irregularity of the pavement surface governs the traffic-induced vibrations in road bridges, but it is either ignored or simulated by means of ideal pavements that differ significantly from real cases. This work presents a detailed dynamic analysis of a heavy truck crossing a 40-m span composite deck bridge using on-site measurements of different existing road profiles, as well as code-based ideal pavements. By activating or deactivating certain spatial frequency bands of the pavement, it is observed that the ranges 0.2 - 1 and 0.02 - 0.2 cycles/m are critical for the comfort of the pedestrians and the vehicle users, respectively. Well maintained roads with low values of the displacement Power Spectral Density (PSD) associated with these spatial frequency ranges could reduce significantly the vibration on the sidewalks and, specially, in the vehicle cabin. Finally, a consistent road categorisation for vibration assessment based on the PSD of the pavement irregularity evaluated at the dominant frequencies is proposed.
Elghazouli AY, Bompa DV, Xu B, et al., 2017, Inelastic behaviour of RC members incorporating high deformability concrete, fib Symposium 2017
Garcia-Troncoso N, Ruiz-Teran AM, Stafford PJ, 2017, Dynamic response of girder footbridges with supplemental damping, Footbridge 2017
Lyu Z, Malaga Chuquitaype C, Ruiz-Teran AM, 2017, Feasability of timber-concrete composite road bridges with under-deck stay cables, 39th International IABSE Symposium
Timber‐concrete composite (TCC) bridges represent an attractive structural system due to the synergistic use of wood and reinforced‐concrete. However, the benefits of TCC bridges can be hampered by their relatively large flexibility that limits their application to long spans. This paper presents an alternative solution for TCC bridges that incorporates post‐tensioned under‐deck tendons. These steel tendons are deviated by two struts and anchored to the cross beams at the support section, effectively subdividing the total span of the TCC bridge into three sub‐spans. The advantages of the newly proposed system are evaluated for 60 m span TCC bridges. This paper shows that the incorporation of under‐deck post‐tensioning effectively changes the critical limit states governing the design of TCC bridges. In addition, the application of post‐tensioned tendons leads to a significant increase in the allowable slenderness and efficiency of structures.
Bompa DV, Elghazouli AY, Xu B, et al., 2017, Experimental assessment and constitutive modelling of rubberised concrete materials, Construction and Building Materials, Vol: 137, Pages: 246-260, ISSN: 0950-0618
This paper focuses on examining the uniaxial behaviour of concrete materials incorporating rubber particles, obtained from recycled end-of-life tyres, as a replacement for mineral aggregates. A detailed account of a set of material tests on rubberised concrete cylindrical samples, in which fine and coarse mineral aggregates are replaced in equal volumes by rubber particles with various sizes, is presented. The experimental results carried out in this investigation, combined with detailed examination of data available from previous tests on rubberised concrete materials, show that the rubber particles influence the mechanical properties as a function of the quantity and type of the mineral aggregates replaced. Experimental evaluation of the complete stress-strain response depicts reductions in compressive strength, elastic modulus, and crushing strain, with the change in rubber content. Enhancement is also observed in the energy released during crushing as well as in the lateral strain at crushing, primarily due to the intrinsic deformability of the interfacial clamping of rubber particles which leads to higher lateral dilation of the material. The test results and observations enable the definition of a series of expressions to estimate the mechanical properties of rubberised concrete materials. An analytical model is also proposed for the detailed assessment of the complete stress-strain response as a function of the volumetric rubber ratio. Validations performed against the material tests carried out in this study, as well as those from previous investigations on rubberised concrete materials, show that the proposed models offer reliable predictions of the mechanical properties including the full axial and lateral stress-strain response of concrete materials incorporating rubber particles.
Ruiz-Teran AM, 2016, Editorial, PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-BRIDGE ENGINEERING, Vol: 169, Pages: 233-234, ISSN: 1478-4637
Madrazo Aguirre F, Wadee MA, Ruiz-Teran AM, 2015, Non-linear stability of under-deck cable-stayed bridge decks, International Journal of Non-Linear Mechanics, Vol: 77, Pages: 28-40, ISSN: 1878-5638
The stability of comparatively more slender decks of under-deck cable-stayed bridges is studied, by considering both the critical loads and the post-buckling behaviour. A potential energy approach is applied to a simplified discrete link and spring model that allows for an exact nonlinear formulation of the equilibrium equations. The physical response is found to be dependent on the ratio of the axial stiffness of the cable-staying system to the flexural stiffness of the deck. The influence of several parameters is analysed and unstable mode interaction is observed to occur under certain geometric conditions. The presented analytical model is compared with a nonlinear finite element model that shows good correlation. Finally, some design criteria and recommendations are suggested, which are relevant for designers of this innovative typology of cable-stayed bridges.
Madrazo-Aguirre F, Ruiz-Teran AM, Wadee MA, 2015, Dynamic behaviour of steel-concrete composite under-deck cable-stayed bridges under the action of moving loads, Engineering Structures, Vol: 103, Pages: 260-274, ISSN: 0141-0296
The dynamic response of under-deck cable-stayed bridges with steel–concrete composite decks under moving loads is presented, and different parameters are considered. The vibrational modes with a strong contribution in the response, the key parameters that control the modal frequencies, and those that reduce the maximum accelerations registered on the deck in a cost-effective manner, are identified. It is found that relatively high accelerations occur and that these can be increased by large load eccentricities. It is also found that maximum accelerations are conditioned by the amplification and cancellation speeds of the loads. Increasing the depth of the deck is determined to be the most effective way to reduce the maximum accelerations. Decks formed by I-beams seem to be quite appropriate from the perspective of dynamic behaviour, while box sections tend to increase the overall cost of the bridge. The findings provide effective strategies to define the most efficient configurations that satisfy the limit state of vibrations, which is critical for this type of bridge.
Camara A, Ruiz-Teran AM, 2015, Multi-mode traffic-induced vibrations in composite ladder-deck bridges under heavy moving vehicles, Journal of Sound and Vibration, Vol: 355, Pages: 264-283, ISSN: 0022-460X
Composite (steel-concrete) ladder-decks represent one of the most common solutions in road bridges nowadays. In these structures the Serviceability Limit State (SLS) of vibrations is traditionally ignored or roughly addressed by means of simple static deflection-based approaches, inherently assuming that the vibrations are controlled by the fundamental longitudinal mode. This work demonstrates that a wide range of high-order vibrational modes, involving the transverse flexure of the slab between longitudinal girders, govern the accelerations recorded in the deck and inside the vehicles. In addition, a new methodology for analysing the Vehicle–Bridge Interaction is proposed, including the approaching platforms, the transition slabs, and the bridge joints. The results suggest that the riding comfort for vehicle users is specially affected by direct effects on the wheels, like the road roughness and possible construction misalignments at the bridge joints, as well as low-frequency vibrations coming from the deck in short or slender bridges. The filtering effects resulting from the average of the response in time and in space when calculating the root mean square acceleration are also explored, and new design parameters are provided. In addition, several structural features (such as the depth and spacing of the longitudinal and transverse steel beams, the thickness of the concrete slab, and the stiffness of the cantilever cross beams at the diaphragm sections) have been studied, and a set of new design criteria has been established. It has been demonstrated that the transverse flexibility of the deck (specially influenced by the support conditions and the slab thickness) is critically important for the users’ (pedestrians and vehicle passengers) comfort, as it controls the aforementioned high-order vibrational modes which govern the dynamic response.
Madrazo-Aguirre F, Ruiz-Teran AM, Wadee MA, 2015, Design criteria of under-deck cable-stayed bridges for short and medium spans, Structural Engineering International, Vol: 25, Pages: 125-133, ISSN: 1016-8664
Under-deck cable-stayed bridges are innovative bridge schemes that can leadto lightweight and highly efficient construction. However, the design of slenderbridges may be governed by the vibrations under traffic live loads. After ahistorical review of bridges with under-deck cable-staying systems and the consequentresearch, the dynamic response of medium- and short-span bridges isanalysed. Eccentric traffic loads are shown to increase accelerations considerably,and the second vertical mode is found to be the main contributor to theresponse. A parametric study shows the strong influence of resonance effectsin the maximum accelerations registered on the deck. In addition, under-deckcable-staying systems are found to be more appropriate for medium-span thanfor short-span bridges from the dynamic viewpoint. Moreover, for medium spans,much more slender decks can be achieved compared with conventional bridgeswithout cable-staying systems. Finally, some design criteria are provided that maybe useful for structural designers.
Madrazo-Aguirre F, Ruiz-Teran AM, Wadee MA, 2015, Nonlinear behaviour of under-deck cable-stayed bridges with steel-concrete composite decks, Pages: 542-549
The effect of geometric nonlinearities in the response of under-deck cable-stayed bridges with steel-concrete composite decks is studied. Influence lines for deflections and bending moments at different sections of the deck are obtained, and these are found to be different to those for conventional bridges. Nonlinearities affect principally the response of lateral subspans, in which both deflections and bending moments are amplified. The permanent state should be studied by taking nonlinearities into account. Deflections under further loads can be obtained with linear models. Geometric nonlinear effects increase design bending moments under ultimate loads by 12% when compared with linear models. Some additional design criteria for designers aiming to design under-deck cable-stayed bridges are hence provided.
Abbas AA, Syed Mohsin SM, Cotsovos DM, et al., 2014, Statically-indeterminate SFRC columns under cyclic loads, Advances in Structural Engineering, Vol: 17, Pages: 1403-1417
Madrazo-Aguirre F, Ruiz-Teran AM, Wadee MA, 2014, Dynamic behaviour of under-deck cable-stayed bridges under the action of moving loads, 37th IABSE Conference, Publisher: IABSE, Pages: 1528-1535
Camara A, Nguyen K, Ruiz-Teran AM, et al., 2014, Comfort in Slender Bridges Subjected to Traffic Loading and Hammering Effects, 37th International IABSE Symposium
Abbas AA, Mohsin SMS, Cotsovos DM, et al., 2014, Shear behaviour of steel-fibre-reinforced concrete simply supported beams, PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, Vol: 167, Pages: 544-558, ISSN: 0965-0911
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