Prestressed Concrete Girder Research Articles

Analytical and Experimental Evaluation of Repairs to Continuous PC Girder Bridge

AbstractThe Wanjiang Bridge, completed in 1976, is the first continuous prestressed concrete (PC) girder bridge erected using the incremental launching method in China. The bridge consists of prism...

Effect of the end cross beams on the railway induced vibrations of short girder bridges

This work is devoted to the analysis of the railway-induced vertical vibrations of simply-supported double track bridges composed by pre-stressed concrete girder decks. Despite the low torsional stiffness that this particular deck configuration exhibits, several structures of this type do exist in both conventional and high-speed railway lines in Spain. Even though railway administrators recommend the construction of transverse or end beams bracing the longitudinal girders at the supports in girder bridges, in several occasions these elements are not built in order to accelerate the construction process. The aim of this study is to evaluate the beneficial effect of installing these transverse beams on the vertical dynamic response of the aforementioned structures and to determine what particular bridges are most affected by the presence of these elements. To this end, a representative ensemble of girder bridges covering a range of span lengths L between 10 m and 25 m has been predimensioned and their dynamic behaviour has been predicted by a finite element model that adopts common assumptions in engineering practice. Conclusions show that installing these elements is particularly relevant in the case of short (10–12.5 m) oblique bridges with a low number of longitudinal girders for a particular deck bending stiffness, leading to an important increase of the first torsion and first transverse bending natural frequencies and to a reduction of the structural response. Finally, experimental measurements on a real bridge belonging to the Madrid-Sevilla high-speed line are included in the final section to illustrate the theoretical derivations.

Recommendations for More Accurate Shear Rating of Prestressed Concrete Girder Bridges

AbstractA numerical parametric study was conducted with two primary objectives: (1) to investigate the accuracy of existing AASHTO shear distribution factors for prestressed concrete girder bridges...

EXPERIMENTAL STUDY ON BEARING CAPACITY OF DANGEROUS AND/OR OLD PRE-STRESSED CONCRETE BOX GIRDERS

In order to obtain the true bearing capacity of dangerous and old pre-stressed concrete box girder bridges, experiments on flexural and shear bearing capacity of full-scale dangerous and old pre-stressed concrete small box girders are conducted to study the mechanical degradation behavior of dangerous and old pre-stressed concrete box girders. Through the residual bearing capacity test of the full-scale prefabricated box girder, the load, deflection, strain and crack width of the test girders are measured and analyzed. The residual bending and shear ultimate capacity and stiffness of the small box girders are analyzed. The bending and shear behavior and failure mechanism of precast box girders in danger are obtained. The comparisons between the results of full-scale test and the calculated value of bearing capacity and also the design value of the internal force of I-Class highway are operated to analyze the actual performance of the small box girder made of dilapidated concrete. The damage reduction coefficient is introduced to establish the formula of ultimate bearing capacity of the girder. The test results stated that the structural damage affected the bearing performance of this box girder. The deflection of the test girder in the uncracked stage did not meet the proof stiffness requirements under the variable load of highway bridge. The calculated results of the flexural bearing capacity are basically identified with the result from full scale flexural test, which is 70% higher than the design bending moment by the internal force of the main girder. The results of full-scale shear tests are respectively 32% and 37% higher than the internal shear design values of the girder. The formulas with damage reduction coefficient for calculating the bending and shearing capacity of the concrete box girders is applicable to evaluate the bearing capacity of the dilapidated concrete girders with more accurate results, which can provide a reference for the evaluation and maintenance of massive existing small concrete box girders in China.

Safety assessment of a concrete viaduct damaged by vehicle impact and an evaluation of the repair

Damage to lower parts of viaducts caused by impact from under-passing high vehicles is relatively frequent. One such incident, in which a viaduct was damaged by the impact from a truck with an improperly assembled hydraulic crane, is considered in this work. The analysis is based on a detailed object damage evaluation, 3D laser scanning, and numerical simulations. The aim of the study is to accurately model the vehicle impact into the viaduct's span. The objective is to diagnose internal damage and to assess the proposed repair concept. No other method will allow discovery of the internal damage, including whether the pre-stressing tendons have been damaged or not. The computational model considers non-linear system dynamics including advanced material definition and the technology of tendon pre-stressing. All complex stages of structural assembly are included in the simulations and the extent of bridge damage is diagnosed. This approach makes it possible to reliably restore the collision event and to assess the safety of internal structural parts. The results from the numerical simulation correspond to the damage measured on the full-scale object. The conducted research indicates that tendons were not damaged as a result of vehicle impact. The structure may be strengthened by means of assembling prestressed concrete girders at both ends. This restoring concept is confirmed analytically. The strengthened structure is intended to show an even greater safety reserve. The proposed strengthening substantially improved structural stiffness, significantly reducing concrete damage and tendon stress in the case of a similar impact in the future. The proposed methodology can also help with research and in practice to assess the safety of other similarly struck and damaged bridges.

Effects of Modeling Parameters on Dynamic Performance of Railway PSC Bridge Girders

This study investigated the effects of finite element modeling parameters on the dynamic characteristics and responses of railway prestressed concrete bridge girders. Free vibration analyses using different modeling parameters showed that the natural frequencies increased when an anchorage was included or when the upper flange thickness was kept constant in the modeling. The maximum dynamic responses of the girder at different speeds of two trains [a high-speed train (KTX) and a freight train] were compared using different modeling parameters. Changes in the flange thickness did not have any significant effect on the maximum vertical displacement. However, the maximum acceleration of the girder for the flange modeled with the originally designed varying thickness was higher than that for the flange modeled with the average thickness as a constant. This difference became more significant as the train speed approached the critical speed of resonance. Regardless of whether the anchorage was modeled, no significant change was found in the maximum vertical displacement for both KTX and the freight train. The vertical accelerations for both the trains were generally lower when the anchorage was modeled. Particularly, the vertical acceleration for KTX near its critical speed of resonance showed larger differences among the finite element models.

Fractal and Multifractal Analysis of Crack Patterns in Prestressed Concrete Girders

Fractal and Multifractal Analysis of Crack Patterns in Prestressed Concrete Girders

Pre-Stressed Concrete Bridge Girder Analysis, Design & Optimization - A Review

Pre-Stressed Concrete Bridge Girder Analysis, Design & Optimization - A Review

Field applicability of a machine learning–based tensile force estimation for pre-stressed concrete bridges using an embedded elasto-magnetic sensor

It has been proposed that pre-stressed concrete bridges improve load performance by inducing axial pre-stress using pre-stress tendons. However, the tensile force of the pre-stress tendons could not be managed after construction, although it directly supports the load of the structure. Thus, the tensile force of the pre-stress tendon should be checked for structural health monitoring of pre-stressed concrete bridges. In this study, a machine learning–based tensile force estimation method for a pre-stressed concrete girder is proposed using an embedded elasto-magnetic sensor and machine learning method. The feedforward neural network and radial basis function network were applied to estimate the tensile force of the pre-stress tendon using the area ratio of the magnetic hysteresis curve measured by the embedded elasto-magnetic sensor. The feedforward neural network and radial basis function network were trained using 213 datasets obtained in laboratory experiments, and trained feedforward neural network and radial basis function network were applied to a 50-m real-scale pre-stressed concrete girder test for estimating tensile force. Nine embedded elasto-magnetic sensors were installed on the sheath, and the magnetic hysteresis curves of the pre-stress tendons were measured during tensioning. The area ratio was extracted and inputted to the trained feedforward neural network and radial basis function network to estimate the tensile force. The estimated tensile force was compared with the reference tensile force measured by the load cell. According to the result, the estimated tensile force can represent the actual tensile force of the pre-stress tendon without calibrating tensile force estimation algorithms at the site. In addition, it can measure the actual friction loss by estimating the tensile force at the maximum eccentric part. Based on the results, the proposed method might be a solution for the structural health monitoring of pre-stressed concrete bridges with field applicability.

Reliability of Super-T PSC girders at serviceability limit state stresses across all span ranges

Reliability assessment gives useful information on the level of performance or adequacy of design rules. There are five standardized Super-T prestressed concrete (PSC) girder sections widely used for bridges in Australia. The Australian standard (AS 5100) requires serviceability limit state criteria of allowable stresses to be met. However, there is not yet an assessment of the performance achieved by these rules. In this study, all potential strand arrangements (more than 50,000) for all Super-T sections, across all feasible span ranges, are assessed. Ten girder-slab bridge decks are analysed; the critical girder in the deck is designed for all possible strand arrangements. Design adequacy is assessed using the annual reliability index. A system reliability analysis is conducted using Ditlevsen bounds to check that none of the four stress limits are exceeded. Generally, it is found that the Super-T girder designs are adequate for most strand arrangements compliant with AS 5100. Further, the reliability varies significantly depending on the selected span, section and strand arrangement. This work informs designers on the reliability performance of Super-T girders designed to AS 5100 and provides background for future revisions of AS 5100.

Case study of failure of long prestressed precast concrete girder during lifting

Improvements in concrete technology, reinforcing systems and manufacturing enable the use of longer reinforced precast concrete girders, contributing to the competitiveness of this solution for bridge decks. The weight of the girders should be limited in order to achieve an optimum between span length, transportation costs and lifting costs. The current tendency in design is to minimize the width of the flanges of the girder. This makes the element more flexible to lateral deformation and increases the risk of lateral instability in temporary situations without lateral supports. This is reflected in an increment of the number of accidents and damages associated with such phenomenon. The main objective of this study is to describe a real case study of lateral instability of a 46 m long prestressed concrete girder during lifting operations as well as to perform a parametric study to understand the limits of the problem observed. In addition to presenting the case study, simplified formulations and numerical simulations are used to assess the safety margins against lateral instability. Special attention is paid to the evaluation of the provisions gathered in codes and guidelines regarding the lateral stability since they might not cover extreme cases.

Operation of a damaged prestressed-concrete girder bridge with repair in Japan

The Myōkō Bridge is a prestressed-concrete (PC) box-girder bridge located in the heavy-snowfall area in Japan. It was opened in 1972, and failure of PC cables due to severe corrosion was found in 2009. It was decided to replace the bridge with a new one based on results of a detailed survey in 2011. It will take 10 years or longer until the new bridge is completed; therefore, the damaged bridge is still used after repair and reinforcement. This paper first reviews the results of a survey on the PC cable failure and the repair work in 2011, when outer tendon cables were installed, reported by the bridge owner. The specific maintenance plan and emergency response system, which were developed based on results of loading tests and continuous structural monitoring, are also presented. Furthermore, a study of structural health monitoring (SHM) on the Myōkō Bridge conducted by the authors is also introduced. Results of the quality evaluation of long-term fibre-optic strain data and the applicability verification of time-series analysis to the structural condition assessment are introduced in a discussion about using long-term SHM data in decision-making for bridge operation.

Investigating Flexural Behaviour of Prestressed Concrete Girders Cast by Fibre‐Reinforced Concrete

The main objective of this research was to investigate the effect of adding polypropylene and steel fibres on flexural behaviour of prestressed concrete girders. Although the construction industry is frequently using prestressed concrete to increase the load‐carrying capacity of structures, it can be further enhanced by using fibres. In this paper, experimental work was carried out to encourage the construction industry in utilizing fibres in prestressed concrete members to improve the mechanical properties of these members. As past investigations on fibre‐reinforced prestressed beams were limited, the present work was done on small‐scale fibre‐reinforced I‐shaped prestressed concrete girders. Six small‐scale prestressed concrete girders were cast comprising a control girder, a hybrid girder, two girders with varying percentages of steel fibres, and two girders with varying percentages of polypropylene fibres. These girders were tested by centre point loading up to failure. It was concluded that, by the addition of small volume fraction of fibres, not only the ductility but also the tensile strength and flexural strength of FRC girders could be improved. It also altered the failure pattern positively by enhancing large strains in concrete and steel. Steel fibre‐reinforced concrete showed higher energy absorption and deflection at ultimate loads in comparison to other specimens.

Failure Mechanism and Mechanical Properties of a Retard‐Bonded Prestressed Concrete Girder While Curing

The mechanical performance and failure mechanism of a retard‐bonded (RB) type prestressed concrete (PC) girder in different curing periods are investigated through four‐point loading experiments. Six RB‐type PC girder specimens with three RB prestressed tendons (PTs) along the longitudinal direction were fabricated. The measurements include the following: the retard‐bonded agent ages versus the load‐carrying capacity of the girder, the deflection of girder, the strain distribution at key cross sections through the girder, the pressure at PT tensile and anchoring ends, crack distribution, and so on. The experimental results indicate that when stretching the PT within proper tensile period, the retarder curing ages have less impact on the cracking load and a greater impact on the ultimate bending strength; the ultimate bending strength of the RB‐type PC girder increased with increased retarder curing. Nonetheless, stretching the PT after excessive retarder curing (after the retarder had solidified completely), the cracks in the PC girder’s pure bending segment are wider and less numerous, the ultimate bending strength of the girder is lower, and its ductility is poor.

Full‐Scale Experimental Investigation of the Static and Dynamic Stiffness of Prestressed Concrete Girders

Cracking damage influences the stiffness of the girders. Many articles in the literatures have studied the development of stiffness of the scale‐down model; however, full‐scale model testing cannot be completely replaced by scale‐down testing because of material component characteristics and boundary effects. This paper deals with the effects of cracking damage on the structural static and dynamic stiffness based on three prestressed concrete (PC) girders which were removed from an old bridge. First, the equivalent flexural rigidity of cracked prestressed concrete girder was assessed using the measured load‐deflection response under cycles of loading and unloading. Then, after unloading, the frequencies were measured on the PC girders supported by the elastomeric bearings. Next, the development of frequency under different damage was studied, and finally, the dynamic stiffness of PC girders with cracks was assessed. The results indicate that the first frequency is more sensitive to the cracking of concrete compared with the second frequency and that the mode shapes are not sensitive to girder damage. The test girders cannot be simplified as an ideal simply supported beam for the purpose of identifying frequencies. In addition, the “final” (the end of the ultimate load case) equivalent flexural rigidity of the girders is 30% of the “initial” (the beginning of the first load case) equivalent flexural rigidity, compared with 50% in the scale‐down test; and the final dynamic stiffness is approximately 84% of the initial dynamic stiffness, whereas the scale‐down test is 72%.

Inspection and Assessment of Highway Bridges in Jordan along the Desert Highway: A Case Study

Bridges, especially highway bridges, are a key factor in nations’ development and flourish. Thus, great care should be taken to maintain and inspect their safety and serviceability. An immediate repair will prevent the loss of life and vehicles damage while crossing underpass and overpassing the heavy deteriorated bridges. Reinforced or pre-stressed concrete bridge girders become structurally deficient because of severed reasons including, increasing in the load requirements, corrosion of pre-stressing strands or reinforcement bars and collision of over-height trucks with the bulb of the concrete girders. The purpose of this case study is to evaluate and assess the damages of the highway bridges in Jordan. Since there is no mandatory program in Jordan for inspection of bridges and evaluating their conditions, this paper presents an inspection and assessment of two highway bridges along the desert highway which is the essential nerve connecting Jordan cities, and it also serves as an international road between many middle east countries. These two Bridges have never been investigated or checked since their construction in the late 1980s. The study results showed that the main factor causing the deterioration of these bridges is the collision of the over-height trucks with their elements. Relying on the collected data, solutions and repair methods were introduced to rehabilitate these bridges and assure their structural safety.

Pre-Stressed Concrete Box Girder Multi Cell (3-Cell) Bridge of Different Shapes a Comparative Study: A Review Paper

Pre-Stressed Concrete Box Girder Multi Cell (3-Cell) Bridge of Different Shapes a Comparative Study: A Review Paper

Deflection analysis of long-span girder bridges under vehicle bridge interaction using cellular automaton based traffic microsimulation.

Deflection is a crucial indicator to reflect the operating condition of girder bridges, which can be used to evaluate structure condition and identify abnormal loading. The paper analyzed the deflection characteristics of long-span girder bridges based on the coupling vibration between stochastic traffic stream and bridge. First, the latest research advances were integrated to form an analytical model of the coupling vibration between stochastic traffic stream and bridge. Then, a generalized Pareto distribution model based on peaks-over-threshold theory was established to predict the extreme girder deflection. Next, a cellular automaton based microsimulation method was proposed to model the traffic loads on bridges, which utilized the intelligent driver car-following model and acceptance distance based lane-changing model. Finally, these theories were applied in the case study of a long-span prestressed concrete continuous girder bridge. It is discovered from the study that, under the coupling vibration between stochastic traffic stream and bridge, the predicted extreme deflection of the case bridge is far lower than the specified design value. Hence, a grading warning model was established and employed to the analysis of deflection monitoring data of the bridge, showing a wide potential prospect of application.

Evaluation of Dorim-Goh bridge using ambient trucks through short-period structural health monitoring system

This paper aims to evaluate the behavior of Dorim-Goh bridge in Seoul, Korea, under static and dynamic loads effects by ambient trucks. The prestressed concrete (PSC) girders and reinforcement concrete (RC) slab of the bridge are evaluated and assessed. A short period monitoring system is designed which comprises displacement, strain and accelerometer sensors to measure the bridge performance under static and dynamic trucks loads. The statistical analysis is used to assess the static behavior of the bridge and the wavelet analysis and probabilistic using Weibull distribution are used to evaluate the frequency and reliability of the dynamic behavior of the bridge. The results show that the bridge is safe under static and dynamic loading cases. In the static evaluation, the measured neutral axis position of the girders is deviated within 5% from its theoretical position. The dynamic amplification factor of the bridge girder and slab are lower than the design value of that factor. The Weibull shape parameters are decreased, it which means that the bridge performance decreases under dynamic loads effect. The bridge girder and slab\'s frequencies are higher than the design values and constant under different truck speeds.

Evaluate of Flexural Behavior of the Prestressed Concrete Girder Using Carbon Fiber Reinforced Plastics via Finite Element Method

Evaluate of Flexural Behavior of the Prestressed Concrete Girder Using Carbon Fiber Reinforced Plastics via Finite Element Method