Reinforced Concrete Bridge Research Articles

Assessment of residual strength of concrete girders rehabilitated using NSM CFRP with cementitious adhesive made with graphene oxide after exposure to fatigue loading

This paper presents the residual strength of reinforced concrete (RC) beams strengthened and repaired by using near-surface mounted (NSM) carbon fibre reinforced polymer (CFRP) with innovative high-strength self-compacting non-polymer cementitious adhesive (IHSSC-CA) and epoxy adhesive after being subjected to fatigue loading. Cementitious materials and graphene oxide were used to synthesise the IHSSC-CA. Ten full-scale beams were manufactured and tested under four-point loading with different loading histories. Five beams were tested under monotonic loading up to failure, and another five beams were then tested under fatigue loading at service load levels up to failure or 3 million cycles, whichever happened first. The fatigue load range and frequency used in this study for testing the beams were designed to simulate the typical fatigue loading and frequency of an actual RC bridge girder under service loading conditions. The effect of fatigue loading was determined by comparing the performance of beams before and after fatigue loading. Finally, 3-D laser profilometry analyses was used to study the deformation of the CFRP strips after fatigue loading. The findings confirm the effectiveness of using IHSSC-CA to strengthen and repair RC beams with NSM CFRP system.

Integrated Condition Rating Model for Reinforced Concrete Bridge Decks

AbstractMost commonly used bridge condition rating systems utilize data emanating from visual inspection reports, inevitably associated with considerable uncertainty. This could possibly lead to un...

Fatigue behavior of naturally corroded plain reinforcing bars

Segments of corroded plain reinforcing bars were firstly extracted from an aged reinforced concrete (RC) pole after its breaking. The testing specimens were then taken from these segments. The cause for corrosion of the specimens was analyzed, and the corrosion degree of the specimens was measured before testing. Tensile loading tests were performed with 3 non-corroded specimens to obtain the mechanical properties of the plain reinforcing bars prior to any corrosion. Axial tensile fatigue tests were conducted with 34 corroded specimens to investigate the fatigue behavior of the naturally corroded plain reinforcing bars. Corrosion of the specimens was initiated by the carbonation of concrete. Two corrosion levels and five stress ranges were considered. Fatigue test results showed that the median fatigue life of lightly and medium corroded plain reinforcing bars was reduced by 48 and 75% respectively under the same stress range of 240MPa by compared with that of non-corroded plain reinforcing bars. Based on the test results, the fatigue Src-N curves of the lightly and medium corroded specimens were presented by using least square method. Then, the predicted fatigue lives and fatigue strengths of naturally corroded plain reinforcing bars were suggested and compared with those of other related literature. The fatigue strength with 50% guarantee rate of lightly and medium corroded plain reinforcing bars is reduced by 18 and 28% respectively under a fatigue loading with cycles of 2 million by compared with that of non-corroded plain reinforcing bars. The fatigue fracture mechanism of the corroded specimens was interpreted by using Scanning Electron Microscope (SEM) images. Further, the pit depth was measured, and the relationship between the relative maximum pit depth and fatigue life of the corroded specimens was explored. It was found that one or more crucially localized pits of a specimen leading to the reduction of fatigue strength had an important influence on its fatigue life. A linear relationship between the relative maximum pit depth and the relative fatigue life of the corroded specimens was observed under three given stress ranges. This study provides a necessary basis for the determination of the remaining fatigue life of aged existing RC bridges.

A Unique Design of R.C.C. Bridge on Godavari River at Sironcha Dist. Gadchiroli -India

Reinforced concrete bridges may have various systems: Beam (with simply supported or continuous beams), Frame, Arch, or combined of it.. Beam reinforced concrete bridges are the most common type, Spans with plate structure are generally used to cover gaps of 6–18 m. Ribbed spans with main beams supporting the plate of .The bridge floor are used to cover gaps of more than 12m. For gaps of more than 40 m, beam spans frequently have box shaped cross sections. Arch systems are most appropriate for bridges on stable soil. The spans of beam-type reinforced concrete bridges are up to 200 m; those of archer in forced concrete bridges, up to 300 m. The main advantages of reinforced concrete bridges are durability and relatively low maintenance cost. Precast reinforced-concrete bridges, using finished plant-Manufactured components, are the type primarily built in the USSR. Methods of suspension assembly of spans and delivery of precast components to local areas by ships are extremely efficient in the construction of large reinforced-concrete bridges.

Performance Degradation of Existing Coastal Reinforced Concrete Bridges and Prediction on Remaining Service Life

Performance Degradation of Existing Coastal Reinforced Concrete Bridges and Prediction on Remaining Service Life

Data Assimilation for Fatigue Life Assessment of RC Bridge Decks Coupled with Path-Integral-Mechanistic Model and Non-Destructive Inspection

Remaining fatigue life of reinforced concrete (RC) slabs subjected to traveling wheel-type loads is estimated by data assimilation procedure, i.e., coupled life-span simulation with inspection data. Multi-scale analysis (MSA) with path-integral-mechanistic models is used for the platform of data assimilation on which the visual inspection of concrete cracking on the members’ surfaces and the acoustic emission tomography (AET) are numerically integrated. For investigating the applicability of the proposed data assimilation, the wheel running experiments of RC slabs was conducted. Both crack patterns (2D) and 3D-AET were measured over the fatigue life till failure. In the pseudo-cracking assimilation, observed cracks are converted to space-averaged surface strains and the internal strain fields are simply assumed by in-plane hypothesis. This pseudo-cracking assimilation brings about fair assessment of the transient maximum deflection, but the residual deformation was found to be overestimated. Another non-destructive inspection data applied in this assimilation is the 3D-AET associated with the acoustic wave velocity, which has much to do with stiffness of some control volume with and without cracking. The AET velocity is converted to the initial fracture parameter of un-cracked concrete based on the elasto-plastic and fracture model used. Although cracking is not explicitly taken into account unlike the pseudo-cracking method, the small number of load repetition automatically generates internal cracks over the volume of analysis domains, and the remaining life of the slabs inspected was successfully estimated.

Probabilistic seismic performance assessment of an existing RC bridge with portal-frame piers designed for gravity loads only

Abstract The present analytical work illustrates a thorough assessment of the seismic performance of an existing reinforced concrete (RC) bridge with framed piers designed for gravity loads only. The seismic response is investigated through advanced, comprehensive and efficient dynamic non-linear analyses. The evaluation of the seismic performance for ductile and fragile components has been carried out with simplified yet reliable formulations, either based on codes or experimentally derived, partially validated with numerical simulations. The effects of far-field and near-source strong motions on the seismic response of the sample bridge have been assessed and discussed in details. Fragility curves are derived using both Cloud analysis and Incremental Dynamic Analysis (IDA) and considering two limit states, i.e. damage limitation and collapse. The outcomes of the refined numerical simulations show that the near-source strong motions tend to impose higher inelastic demand on fragile components of the bridge system than far-field records, nevertheless fragility curves relative to the latter records exhibit higher probability of failure than the near-source strong motion counterparts. For the damage assessment, it is found that the Cloud analysis lead to fragility curves similar to those derived through the IDA procedure. Finally, a new approach facilitating the preliminary identification of the weakest link of the bridge, namely the pier-by-pier fragility, is presented.

Numerical failure analysis of a continuous reinforced concrete bridge under strong earthquakes using multi-scale models

Previous failure analyses of bridges typically focus on substructure failure or superstructure failure separately. However, in an actual bridge, the seismic induced substructure failure and superstructure failure may influence each other. Moreover, previous studies typically use simplified models to analyze the bridge failure; however, there are inherent defects in the calculation accuracy compared with using a detailed three-dimensional (3D) finite element (FE) model. Conversely, a detailed 3D FE model requires more computational costs, and a proper erosion criterion of the 3D elements is necessary. In this paper, a multi-scale FE model, including a corresponding erosion criterion, is proposed and validated that can significantly reduce computational costs with high precision by modelling a pseudo-dynamic test of an reinforced concrete (RC) pier. Numerical simulations of the seismic failures of a continuous RC bridge based on the multi-scale FE modeling method using LS-DYNA are performed. The nonlinear properties of the bridge, various connection strengths and bidirectional excitations are considered. The numerical results demonstrate that the failure of the connections will induce large pounding responses of the girders. The nonlinear deformation of the piers will aggravate the pounding damages. Furthermore, bidirectional earthquakes will induce eccentric poundings to the girders and different failure modes to the adjacent piers.

Cyclic Behavior of Corroded Reinforced Concrete Bridge Piers

Cyclic Behavior of Corroded Reinforced Concrete Bridge Piers

Seismic Assessment of Reinforced Concrete Bridge Under Chloride-Induced Corrosion

Chloride-induced corrosion continues to the main cause of deterioration of concrete structures in the marine areas. To introduce the high rate of corrosion in Persian Gulf area, the axial load-carrying capacity of reinforced concrete columns, which have been exposed to the real corrosive condition of this area about 1.5 years, is measured. Then, a new framework for long-term seismic evaluation of existing corroded reinforced concrete bridge in this area is proposed. Calculation of corrosion initiation time, development of material model considering effects of corrosion, moment–curvature analysis of bridge columns, determination of plastic hinge characteristics, and pushover analysis in longitudinal and transverse directions of the bridge are the main steps of proposed framework. Effects of corrosion include the degradation of cover and core concrete, steel bar, and bonding between concrete and steel bar. By comparing the obtained seismic capacity of bridge at specific time points in bridge service life, effect of corrosion on the long-term seismic performance of bridge is determined. On the basis of analysis results, due to ensuring the long-term seismic performance of seismically designed reinforced concrete bridge in the marine area after 90 years of service, it is suggested in this paper that the design base shear should be increased by 12.5%.

Fiber-based damage analysis of reinforced concrete bridge piers

A fiber beam-column element is adopted to simulate the damage development process of reinforced concrete (RC) bridge piers under quasi-static and earthquake loadings considering global buckling and low-cycle fatigue of longitudinal bars. The tensile strain and low-cycle fatigue are used to represent the damage to longitudinal bars while the compression strain is adopted to calculate the damage to the cover concrete. A section damage index is proposed based on the material damage definition and bridge performance assessment. A set of circular RC bridge piers tested under different uniaxial quasi-static loading regimes are adopted to verify the reliability of the fiber beam-column element and the proposed damage model. Square RC columns subjected to different uniaxial and biaxial quasi-static loadings are used to verify the applicable scope of the fiber element and the damage index in biaxial quasi-static loading. In addition, a series of shaking table model tests on square, rectangular and circular piers subjected to bilateral earthquake ground motions are simulated to further verify the versatility of this model. The results show that, the fiber beam-column element can simulate RC columns/piers with different sections and loading regimes with good accuracy. The damage index proposed in this paper is compared against experimental results and other damage indices and it is found that the proposed index can reflect the damage state at any stage and the gradual accumulation of damage in RC columns/piers more convincingly than most other indices available in literature.

Evaluating Time-Dependent Reliability and Probability of Failure of Reinforced-Concrete Bridge Components and Predicting Residual Capacity after Subsequent Rehabilitation

AbstractThe load-carrying capacity of reinforced concrete bridges can degrade over their service life through the initiation of deterioration mechanisms induced by fatigue, corrosion, cracks, and s...

Axially equilibrated displacement‐based beam element for simulating the cyclic inelastic behaviour of RC members

SummaryDistributed plasticity beam elements are commonly used to evaluate limit state demands for performance‐based analysis of reinforced concrete (RC) structures. Strain limits are often preferred to drift limits because they directly relate to damage and are therefore less dependent on member geometry and boundary conditions. However, predicting accurately strain demands still represents a major simulation challenge. Tension shift effects, which induce a linear curvature profile in the plastic hinge region of RC columns and walls, are one of the main causes for the mismatch between experimental and numerical estimates of local level quantities obtained through force‐based formulations. Classical displacement‐based approaches are instead suitable to simulate such linear curvature profile. Unfortunately, they verify equilibrium only on an average sense due to the wrong assumption on the axial displacement field, leading to poor deformation and force predictions. This paper presents a displacement‐based element in which axial equilibrium is strictly verified along the element length. The assumed transversal displacement field ensures a linear curvature profile, connecting accurately global displacement and local strain demands. The proposed finite element is validated against two sets of quasi‐static cyclic tests on RC bridge piers and walls. The results show that curvature and strain profiles for increasing ductility demands are significantly improved when axially equilibrated rather than classical displacement‐based or force‐based elements are used to model the structural members. Copyright © 2017 John Wiley & Sons, Ltd.

Experimental response of an existing RC bridge with smooth bars and preliminary numerical simulations

The paper discusses the experimental seismic performance assessment of a structural prototype simulating typical existing highway bridges which were designed with poor seismic details. The structural system is a reinforced concrete (RC) 1:3 scale single span bridge which has been tested dynamically with shaking tables by considering strong motions of the 1980 Irpinia (Italy) earthquake. Low-strength concrete and smooth bars were used for the RC circular bridge piers of the tested prototype. Comprehensive modal response analysis has been carried out for the single piers and for the bridge sub-assemblage to estimate period elongations and variations of equivalent viscous damping coefficients at increasing levels of strong motions. The effects of cumulative damage induced by earthquake sequences have also been investigated experimentally. The sample bridge pier possesses low aspect ratio; nevertheless the piers exhibited a flexural response. Fixed-end rotations, with significant longitudinal reinforcement slip, were observed at the base of the bridge pier at about 0.40% lateral drift ratio. As a consequence, a rocking mechanism of the bridge pier initiated; such mechanism affected significantly the pier response at large shaking intensities. An in-depth analysis of local and global response quantities has been provided in order to accurately identify the structural behaviour. Finally, available analytical formulations and refined numerical models were considered to simulate the earthquake response of the tested bridge. The pier lateral response has been investigated by means of push-over analysis and nonlinear time histories. The accuracy of the proposed models, the differences and recommendations for numerical modelling of bridge piers with smooth internal reinforcements are also discussed.

Prediction and Monitoring of Underwater Sound Levels from the Implosion of a Reinforced Concrete Bridge Pier

After the completion of the new east span of the San Francisco–Oakland Bay Bridge in California, large concrete piers of the old span needed to be demolished. To consider using controlled blasting for this action, hydroacoustic levels were predicted and monitored with regard to specified fish and marine mammal criteria. The metrics included peak pressure and sound exposure levels at distances from 25 to more than 4,000 ft from the pier. For peak pressure, the measured levels were slightly higher than estimated, although for sound exposure levels, the measured levels were somewhat lower than estimated because of the effect of surface reflection. A blast attenuation system consisting of a wide bubble stream was used to minimize the hydroacoustic levels in the water surrounding the pier. The implosion event consisted of 588 individual charge detonations ranging from 35 to 21 lb (15.9 to 9.5 kg/delay) spaced 9 ms apart. Although there were 135 individual detonations of the larger 35-lb charges, the highest peak pressures varied in level by 10 to 15 dB during the course of the implosion. The methods for predicting the levels, measured results, analysis of data, and performance of the blast attenuation system are reviewed.

Soil Structure Interaction Effects on Pushover Analysis of Short Span RC Bridges

A three dimensional finite element of nonlinear pushover analysis for short span Reinforced Concrete (RC) bridge with circular piers cross section is modeling to present effects of soil structural interaction (SSI). Structural elements models are including linear foundation springs modeling, and nonlinear RC piers modeling. The paper succeeded to present the SSI effects of nonlinear pushover analysis of short spans RC bridges to determine the significant effects on dynamic characteristics and displacement capacity of short span RC bridges performance; that is increasing within range 11% to 20% compared to baseline pushover analysis of bridge without SSI effects. Results show the bridge stiffness decreases due to SSI effects on the bridge support for more flexible soils types that generates large displacement, with corresponding less base shear in bridge piers and footings by average percentage 12% and 18%, which is important for structural evaluation for new bridge construction and also, for strengthening and repair works evaluation of existing bridges.

Effect of Vertical Earthquakes on Seismic Demands of a Non-Seismically Designed Reinforced Concrete Bridge

Effect of Vertical Earthquakes on Seismic Demands of a Non-Seismically Designed Reinforced Concrete Bridge

Dynamic and Static Behavior of Hollow-Core FRP-Concrete-Steel and Reinforced Concrete Bridge Columns under Vehicle Collision.

This paper presents the difference in behavior between hollow-core fiber reinforced polymer-concrete-steel (HC-FCS) columns and conventional reinforced concrete (RC) columns under vehicle collision in terms of dynamic and static forces. The HC-FCS column consisted of an outer FRP tube, an inner steel tube, and a concrete shell sandwiched between the two tubes. The steel tube was hollow inside and embedded into the concrete footing with a length of 1.5 times the tube diameter while the FRP tube stopped at the top of footing. The RC column had a solid cross-section. The study was conducted through extensive finite element impact analyses using LS-DYNA software. Nine parameters were studied including the concrete material model, unconfined concrete compressive strength, material strain rate, column height-to-diameter ratio, column diameter, column top boundary condition, axial load level, vehicle velocity, and vehicle mass. Generally, the HC-FCS columns had lower dynamic forces and higher static forces than the RC columns when changing the values of the different parameters. During vehicle collision with either the RC or the HC-FCS columns, the imposed dynamic forces and their equivalent static forces were affected mainly by the vehicle velocity and vehicle mass.

FE Evaluation of Reinforced Concrete Bridge Decks with Glass-FRP Composite Bars

In order to resolve the steel corrosion problem in bridge decks, glass fiber reinforced polymer (GFRP) has been recommended as a substitute to the conventional steel reinforcement in bridge decks. However, the use of GFRP bars in bridge decks is still limited by several concerns, including the long-term durability of GFRP bars in the concrete under sustained loadings. Literature review showed that the tensile strength reduction of the GFRP bar should be governed by the sustained stress level in the GFRP bar. In this regard, a GFRP reinforced concrete deck was simulated in this paper, aiming to investigate the sustained stress levels in the GFRP bars through three dimensional finite element (FE) modeling. Per AASHTO LRFD specifications, one lane loaded and two lane loaded cases were examined to identify the maximum tensile strains in the internal GFRP bars subjected to dead loads and HL-93 design loadings. The FE results showed that the maximum tensile stresses in GFRP bars under service loads were less than 1% of the GFRP design strength, which implied that the GFRP bars could have excellent long-term performance in real concrete bridge decks.

Strengthening of a Reinforced Concrete Bridge with Polyurethane-cement Composite (PUC)

This paper describes a new material, polyurethane-cement composite (PUC), used to strengthen a 29-year-old reinforced T-beam bridge in Harbin, China. Polyurethane-cement composite (PUC) is mixed with polyurethane raw material and cement. This technique is completed by pouring Polyurethane-cement composite (PUC) into the template. Ultimate bearing capacity of the bridge after reinforcement was discussed based on the concrete structure theory. The flexural strength of reinforced concrete T-beam bridges strengthened with Polyurethane-cement composite (PUC) was controlled by the design flexural strength of Polyurethane-cement composite (PUC). The main construction process was introduced which included concrete surface treatment, installing template and pouring. To investigate the feasibility of the strengthening method, load tests were conducted before and after strengthening. The results of concrete strain and deflection show that the capacity of the repaired bridge, including the bending strength and stiffness, is enhanced. The crack width measurement also indicates that this technique could increase the durability of the bridge. Thus, this strengthened technique with polyurethane-cement composite (PUC) is feasible, the bridge load posting possibly is removed through this technique.