Intermediate Piers Research Articles

Analysis of numerical models of an integral bridge resting on an elastic half-space

Abstract The paper presents three methods of the numerical modeling of a 60 m long integral bridge structure resting on an elastic half-space. For the analysis, three bridge models were built using Abaqus FEA software. Models A and C represent complex three-dimensional numerical models consisting of the bridge structure and the soil layer beneath it. The soil layer on which the bridge is resting was modeled as a homogeneous, isotropic, continuous, and elastic semi-infinite body elastic half-space. Model B represents a simple three-dimensional numerical model consisting of just the bridge structure. The stiffness of the soil layer beneath the structure in model B was modeled with spring constants derived for shallow footing foundation based on the theory for an elastic half-space. This model represents an engineering approach to the design of an integral bridge. In all models, the bridge deck is monolithically connected with abutment walls and intermediate piers. The bridge is made of cast-in-situ reinforced concrete. All material constants used in the analysis are presented in the table. Self-weight, uniformly distributed load, and thermal longitudinal expansion of the bridge deck were applied to the bridge models. Due to the nonlinear boundary condition used in the supports of the bridge model A, such as contact and friction, the superposition principle cannot be used in the calculations of this model. For this reason, all the loads involved in all bridge models were combined into a single load case and the large displacement formulation was used in the static analysis. The self-weight of the soil layer beneath the structure was omitted in the analysis. The author is focused on the method of modeling an integral bridge structure resting on elastic soil. For the purpose of this paper, only two piers from each model were selected, from which the internal forces and displacements were compared. Based on the analysis, it was concluded that it is possible to design an integral bridge by building its simplified numerical model, once the conditions given in the conclusions are met.

Seismic fragility analysis of long-span rigid-frame bridge on mountainous soft clay site

In order to assess the damage condition of bridge components for a large-span rigid bridge in a soft clay site in a mountainous area in China southwest, a finite element model of a large-span rigid bridge is established based on the OpenSees software, and the joint probability density distribution function of the ground motion strength and seismic demand and the marginal distribution function of the ground motion are introduced into the kernel density function. As a basis to get the method of calculating the fragility of the bridge members, and the method is verified for its feasibility, on this basis, the damage condition of the bridge components are analyzed, and finally the damage condition of the bridge system are analyzed by the first-order bounds method and the improved PCM method (IPCM). The results showed that: (1) Kernel density method (KDE) can effectively calculate the damage probability of each component, for example, under ground motions with PGA equal to 0.2 g, the probability of slight damage of the 1# pier is 29%, that of the intermediate consolidation pier (2# pier ~ 4# pier) is about 90%; the probability of slight damage of the 1# bearing is 48%, and that of the 2# bearing is 87%. (2) Reasonable value of the expansion joints can effectively reduce the probability of main beam collision. In this investigation, the value is taken as 0.18 m ~ 0.24 m. (3) The bridge system is more likely to be damaged than a single component in the system, and the damage probability of a single component cannot be used as a criterion for the bridge system in the actual working condition. Comparing the first-order boundary law with the IPCM method, the IPCM method has higher accuracy.

ПЕРСПЕКТИВИ ТА МОЖЛИВОСТІ БУДІВНИЦТВА МОСТІВ ЗІ ЗМЕНШЕНОЮ КІЛЬКІСТЮ ПРОМІЖНИХ ОПОР НА АВТОМОБІЛЬНИХ ДОРОГАХ УКРАЇНИ ІЗ ЗАСТОСУВАННЯМ СУЧАСНИХ ТЕХНОЛОГІЙ

A certain number of urban overpasses in Ukraine were built in the 1950s and 1960s with short spans and a large number of intermediate piers (e.g., Beresteyskyi overpass in Kyiv). The presence of intermediate piers on the roadway creates an emergency situation due to the disappearing lane before entering the structure on both sides, which leads to the accumulation of cars during rush hour. Such overpasses require reconstruction, which should include a reduction in the number of intermediate piers. As part of pre-design surveys during the reconstruction or construction of new overpasses, it is advisable to conduct laser scanning of the surrounding area to ensure the most accurate reflection of the existing infrastructure, harmonious interaction of the structure with the terrain, optimization of earthworks and use of construction materials. The use of laser scanning is a modern way to control construction and is in demand around the world. Introduction. This article reveals the need to reconstruct urban overpasses with a large number of intermediate piers to avoid the formation of accident-prone areas at the entrances to the structure. Urban bridges and overpasses require a special approach to their design and construction, as in these conditions it is recommended to take into account the aesthetic component, which includes architecturally expressive design solutions. The article presents proposals for the design of such an overpass using laser 3D scanning, which allows for a more detailed study of the design site and simplifies the control of construction work. Problem statement. The presence of intermediate piers on the roadway under overpasses creates an emergency situation due to the disappearing lane, as well as the accumulation of cars during rush hour.

Non-smooth dynamic analysis of curved bridges considering the earthquake-induced end-pounding

Curved beam bridges are widely used to accommodate the needs of complex transportation networks. However, these bridges are characterized by a complex dynamic response under earthquake excitation, and it is common to observe pounding-induced damages at the interfaces between adjacent beams or between the beam and the abutment after high-intensity earthquakes. The identification of pounding occurrences is a challenging task and highly dependent on the computational strategy used. The present paper addresses this problem by proposing and analyzing the suitability of an innovative non-smooth approach to solve the rigid bodies’ dynamic response and contact interactions problem of curved beam bridges subjected to seismic ground motions. To this end, the dynamic equations of motions, including the pounding effects, are first formulated with the introduction of the Lagrange multipliers approach. The unilateral constraints are converted into a linear complementarity problem (LCP) formulation related to the velocity and impulse in the normal and transverse directions. The proposed algorithm of the differential equations in LCP form is successively implemented in Matlab to identify the collision and motion states by accessing the stepwise acceleration time history. A two-span curved beam bridge with an intermediate pier and two adjacent abutments under a single ground motion record is considered for case study purposes to investigate the suitability of the proposed procedure. The accuracy of the proposed method is verified by comparison with finite element (FE) analysis. The analysis results include the bridge’s displacement time history and the motion states of all observed pounding occurrences. Finally, three validation methods, including the LCP relationship, the geometric relationship, and the momentum theorem, are evaluated to examine the validity of the proposed method. The results show that the proposed non-smooth dynamic formulation represents a new rigorous approach to identify and analyze the complex problem of end-pounding occurrence in curved bridges.

Study of Integral Structure behaviour for Rail Structure Interaction in the Proposed Metro Viaduct

Long welded rails (LWR) are preferred in metro rail systems because they provide a smooth ride. They are extremely sturdy, require less maintenance and safe to travel at higher speeds. Rail structure interaction (RSI), especially additional longitudinal stresses in rail, is the major concern in the LWR. UIC standards provide the limitations of additional rail in longitudinal stresses. This paper studies the characteristics of additional forces in long welded rail used in one of the Metro Railway systems in India. The LWR is placed on five spans with integral intermediate piers of balanced cantilever superstructure (BCM). A nonlinear finite element analysis is performed using the analytical tool MIDAS CIVIL 2021 to study the interaction mechanism. For this study, rail and deck (unballasted) are linked with a multilinear elastic spring, as recommended in UIC 774-3R. The study was conducted in accordance with the International Union of Railways and Indian standards. This paper shows a comparison of the rail stresses along the rail due to combined thermal and live loading for both balanced cantilever span and conventional simply supported spans. The results show that rail stresses have significant variation due to bearing articulation, adjacent spans and integral BCM system.

Visual Inspection and Determining Bridge Load Rating over the Torrential Rimac River in Lima, Peru

Nowadays, the appropriate functioning of road infrastructure is a major concern that governments face. One of the structures most vulnerable to failure are bridges. In Peru, the hydrodynamics of torrential rivers, attributable to its geography, generates the collapse in the bridges by scour. Likewise, the increase in service overloads, compared to design loads (HS20), united with the fact that many bridges have more than 50 years in service, is another common factor that contributes to the bridge failures and should be considered in the evaluation of bridges. Therefore, this research aims to inspect, evaluate the load capacity in the superstructure of the Dueñas bridge using the LRFR methodology and propose improvements in the maintenance process. This bridge is made of prestressed concrete built in the 60’s and over the torrential Rimac river in Lima, Peru. The findings, according to the field visit, indicate the main problems are scour in the intermediate pier and damage in the concrete in the structural elements. Additionally, the rating factor (RF) calculated in the beams do not exceed to unit which implies that they only need structural reinforcement. Finally, improvements were proposed for the prevention of failure in the beams and scour in the substructure.

Seismic vulnerability assessment of RC curved bridges piers subjected to bidirectional earthquake

Curved beam bridge is a kind of irregular structure, which has the advantage of adapting to complex terrain, but it is more vulnerable to damage than regular bridge under earthquake. This paper investigates the vulnerability of curved continuous girder bridges under the action of bidirectional earthquake horizontal earthquake, and the difference of vulnerability between side pier and intermediate pier is analyzed. Fragility assessment is performed using an incremental dynamic analysis method subjected to a wide range of as-recorded sequences. A proper engineering demand parameter (EDP) which can result in the most probability of failure at bridges employed in this study is determined. Result indicates that only considering the unidirectional seismic input will underestimate the seismic response and potential damage of the structure, which is not accurate for the seismic performance evaluation of the bridge. Result also shows that the damage probability of the intermediate pier of the curved bridge is higher than that of the side pier, and the more serious the failure, the smaller the difference between the two piers.

Beams with an intermediate pier: Spectral properties, asymmetry and stability

We deal with beams with an intermediate pier, motivated by the investigation of the stability of suspension bridges with two spans. First, we provide a complete spectral theorem for the associated linear stationary fourth-order problem with hinged boundary conditions, determining the eigenvalues and discussing their optimality (in a suitable sense) in terms of the position of the pier. Then, we consider a related nonlinear model with a restoring force of superquadratic displacement type, discussing its stability both from a linear and from a suitable nonlinear point of view. We determine the position of the pier maximizing the stability of the structure and we compare the energy thresholds of instability under hinged, clamped or mixed (left-clamped and right-hinged) boundary conditions. In any case, we highlight that an asymmetric structure is in general more stable.

Safeguarding the pier abutment

In certain partially edentulous cases, the pattern of missing teeth may lead to use of fixed partial denture on pier abutment. However, it has been reported that restoration of two missing teeth and an intermediate pier abutment with a rigid FPD is not an ideal treatment option. Using rigid connector in such situation leads to concentration of stresses on pier abutment. Pier abutment in such case acts as fulcrum leading to more debonding of fixed dental prosthesis which ultimately affects the success of fixed partial denture. Non rigid connector can overcome these problems. Non rigid connector transfers shear stresses to supporting bone & permits abutments to move independently. The non-rigid connector acts as stress breaker between retainer and pontic instead of usual rigid connector. This case report presents a simple method to rehabilitate pier abutment cases.

Linear theory for beams with intermediate piers

The full linear theory for hinged beams with intermediate piers is developed. The analysis starts with the variational setting and the study of the linear stationary problem. Well-posedness results are provided and the possible loss of regularity, due to the presence of the piers, is analyzed. A complete spectral theorem is then proved, explicitly determining the eigenvalues according to the position of the piers and exhibiting the fundamental modes of oscillation. A related second-order eigenvalue problem is also studied, showing that it may display nonsmooth eigenfunctions and that the fourth-order problem cannot be seen as the square of a second-order problem.

Utilization of ultra - high performance concrete for bridge construction – a case study of Kg. Seberang Manong to Pekan Manong bridge

The utilization of Ultra-High Performance Concrete (UHPC) in bridge construction is considered to be quite a new technology in Malaysia and its usage is still in the early stage of implementation as far as bridge design and construction in this country is concerned. The Bridge Design Division, Public Works Department (PWD) has taken the initiative to study and to begin utilising UHPC in designing a 300 m long bridge crossing the Perak River between Kg. Seberang Manong (Kg Menglembu) to Kuala Kangsar, Perak. The purpose of using UHPC is to reduce the number of intermediate piers that need to be constructed within the river channel in order to minimize the impact of debris flow disaster. This will allow free flow of logs thus avoiding them from being trapped and could possibly damage the piers during flooding. The bridge has 5 spans with the longest span of 70 m in length that uses UHPC in its construction. In this bridge construction, it is quite impossible to use typical normal concrete commonly utilize in conventional concrete bridge project that normally limits the span length to only 40 m. This project is also a pilot project in PWD that uses Malaysia Civil Engineering Standard Method of Measurement (MYCESMM), replacing the current Malaysian Standard Method for Measurement of Civil Engineering Construction. The MYCESMM covers a wider range of civil engineering works. This project is expected to contribute towards delivering cost effective civil engineering projects through the adoption of best practices in the preparation of the bills of quantities (BQ). The successful application and construction of this pilot project will have a great prospect in encouraging more projects to use UHPC and MYCESMM in the upcoming projects in Malaysia

Replacing the deck slab on a post-tensioned, prestressed-concrete composite girder bridge in Japan

Repairs were required to a corroded post-tensioned prestressed-concrete continuous-girder bridge that had been in service for over 35 years in the Chuo Expressway in Japan. The work included reinforcing the bridge girders with external cables and partially replacing the bridge deck slab at intermediate piers. The load-carrying capacity of the existing bridge and reinforcement design for the replacement slab sections were based on a soundness assessment following detailed investigations. This paper describes the considerations for examining, planning and designing the replacement of large sections of slab on a post-tensioned, prestressed-concrete, continuous-girder bridge.

Seismic Performance Evaluation of a Fully Integral Concrete Bridge with End‐Restraining Abutments

A fully integral bridge that is restrained at both ends by the abutments has been proposed to form a monolithic rigid frame structure. Thus, the feasible horizontal force effect due to an earthquake or vehicle braking is mainly prevented by the end‐restraining abutments. In a recent study, a fully integral bridge with appropriate end‐restraining abutment stiffness was derived for a multispan continuous railroad bridge based on linear elastic behavior. Therefore, this study aims to investigate the nonlinear behavior and seismic capacity of the fully integral bridge and then to assess the appropriate stiffness of the end‐restraining abutment to sufficiently resist design earthquake loadings through a rigorous parametric study. The finite element modeling and analyses are performed using OpenSees. In order to obtain the force‐deflection curves of the models, nonlinear static pushover analysis is performed. It is confirmed that the fully integral bridge prototype in the study meets the seismic performance criteria specified by Caltrans. The nonlinear static pushover analysis results reveal that, due to the end‐restraining effect of the abutment, the lateral displacement of the fully integral bridge is reduced, and the intermediate piers sustain less lateral force and displacement. Then, the sectional member forces are well controlled in the intermediate piers by a proper application of the end‐restraining abutments.

ANALYSIS OF THE TIME COURSE OF A BRIDGE ABUTMENTS SETTLEMENT

The paper deals with the time course of the bridge abutments settlement (consolidation of the subsoil) on the motorway D4 in Stupava, Slovakia. The bridge abutments are founded on an earth embankment 5.5 meters in height and a group of piles. Over 6 years of geotechnical monitoring after the construction of bridge abutments, there were measured settlements from 102 to 106 mm. The measured settlement of intermediate bridge piers was only up to 16 mm. Geotechnical calculations and analysis are focused on the comparison of the final settlements prognosis and its time course with the real measured values.

Rehabilitation and seismic upgrading of the masonry arch bridge over the Magra river in Villafranca

The paper deals with the rehabilitation of an historical masonry bridge crossing the Magra river and connecting the small towns of Mulazzo and Villafranca in the northern part of Tuscany (I).The masonry arch bridge, characterized by eight arches spanning 19 m around each and by around 12 m height intermediate masonry piers on shallow foundations, was built in 1874.Since the original carriageway width was not sufficient to allow two lanes, in 1961 it was widened by means of two lateral prestressed concrete beams, supported by the piers, so hiding the arches and modifying severely the original aspect of the bridge itself.In 2011, during the Magra flooding, two arches on the Mulazzo side collapsed due to scour of the extreme pier.The reconstruction of the collapsed arches and rehabilitation and the strengthening of the bridge, which has been completed last year, is discussed and the execution of the interventions, which has performed without erection of temporary support in the riverbed, is also illustrated.Particular attention is devoted to the original solutions which have been adopted for the full seismic upgrading of the bridge according to the Italian Building Code currently in force, recovering the original architectural aspect of the bridge and widening the carriageway as well.

Comprehensive investigation on the cause of a critical crack found in a diagonal member of a steel truss bridge

Ikitsuki Bridge is a three span continuous truss bridge with a length of 800m, which was completed in July 1991. In December 2009, a crack which seriously damages the safety of the bridge was found in a diagonal member near an intermediate pier during an inspection for determining points to be annually inspected. In order to identify its cause, some tests on the material used for the cracked member were conducted, and a long-term monitoring of wind and vibration of some diagonal members with similar structural characteristics to the cracked member had been carried out since December 2011. In this article, the outline of the crack is presented and the main causes of the crack are discussed based on the results of the tests and monitoring. The conclusions can be summarized as follows: (i) The crack initiated and propagated to become approximately 200mm long as a fatigue crack. The quality of material and weld satisfies the requirement for them. (ii) The vibration of the diagonal members is induced by the wind with the velocity of 6–8m/s and higher than 15m/s in the direction approximately normal to the bridge longitudinal axis. The maximum stress range induced by the vibration due to 6–8m/s wind is approximately 30–40MPa, while that due to the wind blowing at the velocity of over 15m/s can be 195MPa. (iii) These wind-induced vibrations are thought to be the main cause of the fatigue crack.

Crossing motorways under traffic without intermediate piers

AbstractThe European research programme SBRI attempted to reveal the costs caused during the service life of a bridge – direct costs for the bridge owner as well as indirect costs for users. The principal results of SBRI should make it possible to take better account of the true costs of a central pier by considering the risks in the construction phase and those that may threaten the highway overpass during its service life.CEREMA has developed two economic solutions to reach the objective of avoiding the central pier: The solution implemented at Ko Wé Kara in New Caledonia is a steel‐concrete composite tied arch bridge with innovative and economic details: innovative radial hangers made of welded plates, and innovative reinforcement against accidental impact of over‐height vehicles. One other possible solution is the composite steel‐concrete gantry bridge. The European research programme PRECOBEAM allowed the use of tests and experimental projects to finalize a new system of connection to lower the cost of this type of structure: a strip along which the cutting line of the steel dowels is made in a clothoid shape (CL), which improves the fatigue resistance. CEREMA introduced this innovation in its research programme. A composite structure can take various forms. It can associate, for instance, the steel web of a beam directly with a concrete flange. It can also constitute a composite deck with a bottom plate stiffened by connecting CL‐shape indented strips. An outstanding project of this type in New Caledonia is described in detail. Of course, this type of bridge is an integral bridge and the article includes some recommendations for the design and construction of integral bridges.

Research and construction of geosynthetic-reinforced soil integral bridges

Geosynthetic-reinforced soil (GRS) integral bridge was developed to overcome several inherent serious problems with conventional type bridges comprising a simple-supported girder (or multiple girders) supported via bearings typically by RC abutments retaining unreinforced backfill (and a pier or piers for multiple girders). The problems include: (a) relatively high construction and maintenance costs with relatively long construction time resulting from the use of bearings and massive abutment structures usually supported by piles; (b) bumps immediately behind the abutments; and (c) a relatively low stability of the girders supported by roller bearings and the approach embankment against seismic and tsunami loads. For a GRS integral bridge, a pair of GRS walls (and an intermediate pier or piers if necessary for a long span) are first constructed. After the deformation of the supporting ground and the backfill of the GRS walls has taken place sufficiently, steel-reinforced full-height-rigid (FHR) facings are constructed by casting-in-place concrete on the wall face wrapped-around with the geogrid reinforcement. Finally a continuous girder is constructed with both ends integrated to the top of the FHR facings. The girder is also connected to the top of an intermediate pier, or piers, if constructed. The background and history of the development of GRS integral bridge is described. The first four case histories, one completed in 2012 for a new high-speed train line and the other three completed in 2014 to restore a railway damaged by a great tsunami of the 2011 Great East Japan Earthquake, are reported.

Simplified assessment of cable-stayed bridges buckling stability

A simplified procedure for assessing of the overall elastic buckling stability of cable-stayed girder bridges at preliminary design stages is presented. The evaluation of the buckling modes and load factors is based on the analogy of taking a cable-stayed bridge deck as a beam–column on an elastic foundation. A new method of assessment of the model uniform continuous vertical stiffness, provided by the main span stays and reduced by the stays side span flexibility, is proposed. The results of this method are in good agreement with those of geometrical non-linear finite element analyses, typically performed at final design stages. The influence of the stay system, cable spacing, towers height, the live load pattern, and the number of the intermediate piers are finally analyzed.

Dynamic Behavior of Cable-Stayed Bridge under Moving Vehicle and Train

In this study, dynamic behavior of cable-stayed bridge under moving vehicle and train was analyzed. The parameters considered are the main span length of bridge and the existence of intermediate pier at side span. For the parametric analysis, cable-stayed bridges with 400m and 700m main span (with and without the intermediate pier at side span) were selected. From the vehicle/train-bridge interaction analysis, the intermediate pier was found very effective to reduce the dynamic amplification of girder and stay-cables.