Prestressed Concrete Bridge Research Articles

Chloride Transport in Interfacial Zone of New–Old Concrete Joints of Precast Prestressed Concrete Bridges under Fatigue Load

Chloride Transport in Interfacial Zone of New–Old Concrete Joints of Precast Prestressed Concrete Bridges under Fatigue Load

Load Test Analysis of a Long-Span Prestressed Nano-Concrete Highway Bridge.

In order to solve the problem of vehicle-bridge coupling vibration of a continuous semisteel bridge, the main bridge type of long-span prestressed concrete girder bridge, the author proposes a bridge safety test system based on the dynamic and static load test. The system combines the change of stress and deflection with the vibration amplitude of the bridge body, and using the modeling assistant in large-scale finite element software MIDAS/CIVIL, a three-dimensional finite element real bridge model is established, including input of section data, the input of boundary conditions, and the input of loads. The result obtained is as follows: the structural verification coefficient of the control strain of the main girder under each working condition is not greater than 1.0, indicating that the flexural rigidity of the structure meets the design requirements. In addition, under each working condition, the ratio of the residual strain after unloading to the measured total strain is less than 20%. Under each working condition, the deflection calibration coefficient of each control section is less than 1.0, and the ratio of residual deflection to total deflection of each measuring point is at most 3.9%; each residual deflection is small. The damping ratios are all less than 5% of the empirical damping ratio of concrete members, indicating that the bridge structure is in good condition. The result obtained by the author is compared with the standard allowable value and the theoretical calculation value, so as to provide a basis for the study of the bearing capacity of similar bridges and to verify the standardization and rationality of the existing bridge structural design.

Shear design of precast prestressed concrete NEXT beam bridges: A critical assessment

Northeast extreme tee (NEXT) precast prestressed concrete beams have recently emerged as a promising solution to accelerate bridge construction and enhance the sustainability of bridges. To date, several studies on the live load distribution factor (LLDF) for moment and shear in NEXT F beam bridges have been reported, which indicated that using the AASHTO LRFD LLDF for moment in NEXT F beam bridges could provide a sufficient safety margin; however, a 20% increase in the LRFD LLDF for shear was recommended for the safety of shear design. This paper intended to investigate the required transverse shear reinforcements in NEXT F beam bridges by using a factor of 1.2 for the LRFD LLDF for shear. A comprehensive study was carried out by considering various parameters, including concrete strength, beam section, bridge section, and span length. Results from this study showed that providing the minimum transverse shear reinforcement could offer a sufficient safety margin for the shear design of NEXT F beam bridges, even with an increase of 20% on the LRFD LLDF for shear. It is recommended that a factor of 1.2 be used for the LRFD LLDF for shear to ensure a safe design of NEXT F beam bridges, though the minimum transverse reinforcements will be likely to control the shear design.

Structural Behavior of Prestressed Concrete Bridge Girder with Monolithic Joint

The paper presents the results of a test on a composite bridge girder of a length of 42.0 m, which was performed to assess its resistance, stiffness and crack resistance. Composite reinforced concrete beam with three blocks is joined by the two monolithic joints. When testing a beam with monolithic joint in terms of stiffness, crack resistance and strength, a load of 943.5 kN was achieved without cracking, which is 26.8 % higher than the required one.

Comparative study of long-term displacement measurement methods − Focusing on a Pre-stressed concrete bridge under construction

Bridges continuously deflect over their entire lifetime, mostly due to fatigue, deterioration, time-varying material properties, or changes in boundary conditions. Long-term displacement can be employed in both the construction and operation stages for quality control and prognostic maintenance measures. Despite their versatile advantages, conventional sensors are limitedly employed for long-term displacement measurements owing to practical limitations such as clearance occupation, financial feasibility, long-term drift error, or insufficient displacement resolution. This study aims to demonstrate the long-term application of displacement measurement methods on a full-scale railway bridge using a dual-camera system, a light detection and ranging (LiDAR) system, a strain gauge, a linear variable differential transformer (LVDT), and a ring gauge for long-term monitoring for 548 days. The resulting displacements are comparatively analyzed based on dead loads and weather conditions, elucidating the practical issues arising in the long-term displacement monitoring of full-scale bridge.

Repairing Post-Tensioned Prestressed Concrete Bridge Girders with Frost-Heaving Damage

Repairing Post-Tensioned Prestressed Concrete Bridge Girders with Frost-Heaving Damage

Long-term performance of a continuous box-girder bridge constructed using precast segments with wet ultra-high-performance concrete (UHPC) joints

Although the precast segmental construction (PSC) technique can relieve age-dependent difficulties and accelerate bridge construction as compared to the cast-in-situ construction (CSC) technique for long-span prestressed concrete box-girder bridges (LSPCBB), the ordinary concrete joints between adjacent precast segments are risky. In order to improve the bond strength at the joint interface and enhance structural reliability, ultra-high-performance concrete (UHPC) can be used to fill joints as a new cementitious material with high strength, ductility, and durability. Thus, the effect of the naturally cured UHPC shrinkage and creep on the bridge's long-term performance should be evaluated. The present study numerically investigates the long-term bridge performance constructed by the PSC technique with wet UHPC joints. One cast-in-place segment using the CSC technique is replaced by one precast segment and one cast-in-place UHPC joint using the PSC technique in the bridge model. A creep coefficient equation in an existing code and a shrinkage strain equation fitted from the test data for the UHPC are verified, and an equivalent temperature drop method is used for simulating pretension forces of the prestressing strands in the numerical model. Through comparison with the CSC technique, the technical advantages in reducing long-term deflection, rotation, prestress losses, and improving normal cross-sectional stresses are quantitatively highlighted for the UHPC enhanced PSC bridge.

Stiffness identification of deteriorated PC bridges by a FEMU method based on the LM-assisted PSO-Kriging model

Stiffness identification from measured responses is an important part of structural health monitoring, in which finite element model updating (FEMU) is a widely studied method. However, the practicability of this method still needs to be improved when applied to large deteriorated civil structures. In this paper, a new FEMU strategy based on the PSO (particle swarm optimization)-Kriging model assisted by the Levenberg–Marquardt (LM) algorithm is proposed for the stiffness identification of deteriorated long-span prestressed concrete (PC) continuous girder bridges. The strategy is implemented in two phases: global stiffness identification based on the LM algorithm is adopted in phase I to determine the sampling interval of the identification parameters; then, in phase Ⅱ, the girder is divided into segments, and the accurate value of each segment stiffness is determined. The PSO-Kriging model is employed to facilitate the high accuracy and efficiency of the method. The effectiveness of the proposed method is demonstrated through comparison studies in an existing experiment and a full-scale test, and the parameter selection of the method is also discussed.

Assessment of structural health of an existing prestressed concrete bridge by finite element analysis

ABSTRACT This study investigates the feasibility of an alternative structural health monitoring (SHM) technique for an existing, post-tensioned, prestressed concrete bridge in Niigata, Japan. Currently, a static SHM system is in place to detect the progress of damages within the bridge. However, the existing system cannot properly monitor the structural health of the bridge including the periodic vibration, which is one of the damage-sensitive features of interest. Therefore, to effectively detect the real-time performances of the bridge, a three-dimensional (3D) Finite Element (FE) model was developed as a reference and verified using on-site load-deflection test results. After validating the reference FE model, different damage scenarios, such as degradation of concrete, corrosion & rupture of steel tendons and missing tendons, were incorporated in the FE models. Based on non-linear structural and Eigenvalue analyses, natural frequencies and mode shapes of the bridge remain constant even after careful consideration of all types of damages in the FE model. However, vertical displacements are observed to increase for the damage scenarios. Although the effect of tendon rupture and corrosion showed negligible influences on the vertical displacement, the deterioration of the concrete largely influenced the vertical displacement. Additionally, crack widths were found to vary with damage types. Brifely, this study recommends some effective indicators to monitor the structural conditions of the bridge using FE analysis (FEA).

A statistical index based damage identification method of a bridge using dynamic displacement under moving vehicle

Potential damage identification is essential to avoid the sudden and premature failure of aging bridges, which have attracted ample attention over the decades. This paper proposes an output only data driven technique for damage identification which will not require any physical model of the structure nor any known input excitation. Statistical moments have been considered as the key feature for the proposed method of damage identification which has been derived from the measured vehicle-induced dynamic displacement responses of a pre-stressed concrete I-girder bridge. The displacement responses data of a bridge is influenced by many factors, including Vehicle-Bridge Interaction (VBI), vehicle speed and road roughness. The interaction between vehicles and bridges includes dynamic models for bridge structure subsystem and vehicle subsystem, interaction constraints and road roughness modelling. Firstly, the coupled formulation is derived based on the interaction constraints. Then, Newmark’s β method is utilized for solving the coupled VBI problem to extract the vehicle-induced displacement responses. Later, the statistical moment is calculated from the Power Spectral Density (PSD) of the displacement response retrieved from sensors positioned on the span of the bridge for both damaged and undamaged conditions. A damage index named Curvature of Statistical Moment Difference (CSMD) is calculated to identify the damages. Artificial damage is incorporated through the reduction of structural stiffness of the bridge element. The results of the study demonstrate the method's capability to identify and locate damage at any position of the bridge span and assess the relative severity of the damage. The effect of varying pavement roughness conditions is also considered in this study.

Experimental Measurements in the Field of Prestressing Force Monitoring

Abstract In recent years, lots of researchers have given attention to prestressing evaluation in existing prestressed concrete structures. In Europe, many existing prestressed concrete bridges are about to reach their limit of service life and exhibit signs of deterioration. Therefore, reliable, and effective methods for determining the actual state of prestressing are needed. Indirect methods represent a valuable tool for the structural assessment of prestressed concrete members in service. These methods include, e.g., Saw-cut method, Structural response method, Barkhausen noise technique, or Wire-cutting method. The presented paper summarises indirect measurements focused on prestressing force monitoring using the aforementioned techniques performed in the Laboratory of Civil Engineering of the University of Žilina.

Structural Behavior of Prestressed Concrete Bridge Girder with Epoxy Joint

The study object is a prototype of a composite bridge prestressed concrete beam with a length of 42.0 m for road bridge desks for perception of impact from motor vehicles in the form of A14, NK-120 and NK-180 loads.
 The experimental deflection of the beam in the midspan had a value equal to fexp = 62.4 mm at a load of 2Pк = 436 kN, which was 75.2% of the control deflection value.
 Based on the test results, the girder block joints with "tooth" and "notch" device are found to be imperfect.
 The experimental load of 2PMAX = 822.7 kN was achieved during the tests, which exceeded the control load equal to 2Pк = 744 kN when checking the strength of the composite beam and the control load equal to 2Pк = 790 kN when checking the strength of No. 1 and No. 2 joints.

Finite-Element Analysis of Adjacent Concrete Box Girders Transversely Post-Tensioned at the Top Flanges Only

A three-dimensional non-linear finite-element model (FEM) was constructed using a commercial software (ATENA-Studio) to investigate the transverse load distribution behavior of adjacent precast prestressed concrete box-girder bridges. An innovative connection between box girders was used, where transverse post-tensioning was applied at the top flanges only eliminating the need for intermediate transverse diaphragms. The FEM was validated in terms of deflections, strains, cracking and ultimate loads against experimental results previously reported by the authors. The validated FEM was then used to perform a parametric study investigating the influence of adding concrete topping, load location, and bridge width on the transverse load distribution behavior of the newly developed connection. The results of the FEM demonstrated the efficiency of concrete topping in limiting mid-span deflections up to 25%. Additionally, the maximum live load moment distribution factors (LLMDFs) for different load locations and bridge widths were evaluated.

Rational and sustainable procedure in the design of bridges using pre-stressed concrete beams a theoretical practical method

Currently there is not a direct procedure for the design of this bridge system, the procedure is still based on trial and error, there are no studies that give us both the optimum number of beams and other characteristics such as the correct thickness of the slab or its adequate strength. Keeping in mind the concept of optimization, which supports the idea of sustainability and environmentally friendly structures, we apply this concept to the design of pre-stressed concrete girder bridges, which are an integral part of the road network in most countries of the world. Knowing also that concrete is the most produced material by man and that without it, it would be difficult to understand our current world, due to its own characteristics that make it unique when it comes to sustainability, however, its production requires energy and material consumption, that is why an optimal design of a superstructure will lead to the minimum consumption of materials obtaining a more friendly design with nature. It is a global necessity to obtain and deliver concrete structures that meet the conditions of sustainability.

Failure Investigation of under Construction Prestressed Concrete Bridge in Chitwan, Nepal

On 6 April 2021, a 200 m-long under-construction prestressed concrete bridge failed in the Chitwan District in central Nepal. Two of the four bridge spans collapsed without any notable evidence of dynamic force application. Under-construction bridge failures are sometimes reported and can have a significant impact on the future construction adjustments. Thus, a detailed study of failure mechanisms will be insightful for the structural engineering community. Aiming to document the failure modes and exemplify lessons for improvement, this paper reports the detailed component level failure mechanisms of the bridge using visual inspection, site measurements, finite element modeling, and some forms of non-destructive testing. The chronological failure mechanisms are presented based on the field evidence and juxtaposed with the results of analytical modeling. The sum of findings highlights that the dead load failure, triggered by the settlement of falseworks, is the most critically governing factor that initiated and aggravated the damage scenario.

Bayesian inference for predicting the long-term deflection of prestressed concrete bridges by on-site measurements

Predicting the long-term deflection of prestressed concrete bridges (PSCB) by the deterministic models is subject to significant epistemic uncertainties, and the Bayesian statistics provide a practical way to make more reliable prediction by use of the long-term measurements. In this paper, a comprehensive Bayesian inference frame was built, in which the model parameters associated with creep, shrinkage, dead load and prestress level were updated by the Bayesian inference of the deflection measurements. A 3-D time-dependent finite element model was constructed, based on which a surrogate model was built to enhance computation efficiency. The Markov Chain Monte Carlo (MCMC) algorithm was adopted to approximate the manifold of the posterior distribution. In the case study, two sets of deflection of the case bridge were utilized to perform the Bayesian inference in a sequential manner. The results revealed that the updated models could produced better fit to the measurements than the deterministic model, while the variance of the prediction was significantly reduced. The updated model revealed changing trends of the time-dependent deflection, which characterizes a later-age acceleration from the initial moderate trend. Based on the updated models, the time-dependent reliability associated with the limit states defined by deflection limits was computed. For such a task, the MCMC-based pre-sampling and the quasi-optimal importance sampling were adopted to reduce the variance of the computation.

Analysis of concrete T-girder using MIDAS

The concept of pre-stressed concrete appeared in the year 1888. In this present engineering technology, durable and sustainable bridges play an important role for the socio-economic development of the nation. Owners and designers have long recognized the low initial cost, low maintenance needs and long-life expectancy of pre-stressed concrete bridges. This is reflected in the increasing market share of pre-stressed concrete, which has grown from zero in 1950 to more than 55 percent today. This growth continues very rapidly, not only for bridges in the short span range, but also for long spans with excessive length which, here therefore, has been nearly the exclusive domain of structural steel. Many bridge designers are surprised to learn that precast, pre-stressed concrete bridges are usually lower in first cost than all other types of bridges coupled with savings in maintenance, precast bridges offer maximum economy. The precast pre-stressed bridge system has offered two principal advantages: it is economical and it provides minimum downtime for construction.

Comparative Study of Long-Term Displacement Measurement Methods − Focusing on a Pre-Stressed Concrete Bridge Under Construction

Comparative Study of Long-Term Displacement Measurement Methods − Focusing on a Pre-Stressed Concrete Bridge Under Construction

Analysis of concrete T-girder using MIDAS

The concept of pre-stressed concrete appeared in the year 1888. In this present engineering technology, durable and sustainable bridges play an important role for the socio-economic development of the nation. Owners and designers have long recognized the low initial cost, low maintenance needs and long-life expectancy of pre-stressed concrete bridges. This is reflected in the increasing market share of pre-stressed concrete, which has grown from zero in 1950 to more than 55 percent today. This growth continues very rapidly, not only for bridges in the short span range, but also for long spans with excessive length which, here therefore, has been nearly the exclusive domain of structural steel. Many bridge designers are surprised to learn that precast, pre-stressed concrete bridges are usually lower in first cost than all other types of bridges coupled with savings in maintenance, precast bridges offer maximum economy. The precast pre-stressed bridge system has offered two principal advantages: it is economical and it provides minimum downtime for construction.

Long-Term Behavior of a Prestressed Concrete Bridge with Corrugated Steel Webs

Abstract Long-term performance is one of the less-studied cases of the prestressed concrete bridge with corrugated steel webs. In this study, the time-dependent behavior of a bridge of this type wa...