PC Girder Research Articles

Shear resistance mechanism of prefabricated large-scale gerber girder

In this study, shear tests were conducted to investigate the shear resistance mechanisms of Gerber precast concrete (GPC) girders consisting of PC end units, PC girder units, and cast-in-place concrete. To this end, individual PC end-member and mid-girder specimens were fabricated along with five GPC girder specimen with CIP concrete. The key test variables were overlapping (hanging) length and connection details of the mid-girder and end units. The test results showed that the shear performance of the composite GPC girder was significantly influenced by the connection details of the end-member and mid-girder. In the specimen where the mid-girder was simply assembled with the end-member without bolts, the failure was dominated by the damage concentrated on the bottom flange of the end-member. In contrast, in the specimen with the end-member and mid-girder assembled with bolts, there was no significant damage to the connection region, resulting in exerting full shear capacity. Additionally, based on the load–displacement response, crack pattern, and strain behavior measured from the experiment, the load-transfer mechanism of the GPC girder was estimated and reflected to propose a strut-and-tie model (STM) for the shear design of the GPC girder. The proposed STM was found to evaluate the shear strengths of the GPC girder specimens with a higher degree of accuracy than the shear strength evaluation method based on design code equations. Therefore, tied-arch mechanism can be assumed to dominate the main shear transfer mechanism when designing the GPC girder.

Experimental based time-dependent reliability assessment of corrosion initiation for PC girders in frozen marine environment

Chloride induced corrosion is the main reason for the deterioration of concrete structures in marine environments, and the prediction of corrosion initiation life is one of the greatest challenges for preventative maintenance. To conduct a corrosion initiation assessment of PC girders in frozen marine environment and support preventative maintenance, a time-dependent reliability assessment method is developed. Long-term exposure experiments and in-house tests are combined to calibrate the chloride diffusion model, and then a probabilistic diffusion model is proposed based on the randomness of the key model parameters. Through the analysis of the target reliability index of corrosion initiation, the risk-function based time-dependent reliability assessment method is developed. Finally, a case study is introduced to illustrate the application of the proposed method. It is found that the surface chloride concentration on concrete structures in frozen marine environments increases at the beginning of service life and it tends to be stabilize when the service time is around 9–10 years. The age reduction factor of chloride diffusion can be described as the linear function of cementitious composition. The target reliability indices of corrosion initiation are suggested as 2.46, 1.50 and 1.13 for the referenced periods of 1, 10 and 20 years. The corrosion initiation life is very sensitive to the tensile stress level of concrete, and it decreases linearly with the increasement in tensile stress when the stress is not higher than 2 MPa.

Impact of Anchored CFRP Composites on the Strengthening of Partially Damaged PC Girders

This manuscript investigated the effect of anchorage CFRP wrapping sheets, bolts, and laminate interlock on increasing the efficiency of flexural strengthening for the post-tension girder using CFRP composites techniques longitudinal laminates at the soffit for partially damaged loss of about 14.3% from its area of prestressed concrete beams, and the impact on restoring the original flexural capacity of PC girder. Mitigating delamination of the soffit of horizontal laminates (CFRP). The texture of the laminate and anchorages influenced the stress of the laminate carbon fiber, the mode of crack propagation and failure, and consequently, the beam's attitude has been investigated in this manuscript. The experimental findings demonstrated that using CFRP laminates significantly affects strand strain, especially when anchorage wrapping is applied. The laminates CFRP-EB enhanced the flexural capacity by around 13% of the original strength, which equates to a 13% increase in strand damage. Despite an increase in flexural capacity of 20%, 22%, and 29% when using anchorage wrapping, mechanical bolts, and laminate interlock, respectively. It has been proposed to use quasi-experimental equations to predicate the actual stress of un-grouted strands, considering the influence of CFRP laminate and wrapping anchorage sheets techniques only. The experiment outcomes demonstrated that using Anchored CFRP significantly affects load-carrying capacity and cracking load by up to 29% and delays the bonding failure.

AEM analysis of asphalt pavement on PC bridge under the coupling effect between impact from ruptured vertical PC bars and temperature

The resistance of asphalt pavement against impact loading from corrosion-induced ruptured vertically tightened PC bars in PC bridges is critical for traffic safety. When vertically tightened PC bars in PC girders rupture, they protrude from the anchorage section and damage the asphalt pavement, which may cause severe accidents. In this study, the performance of a two-layered asphalt pavement system under the coupling effect between impact and temperature, with the impact caused by a vertically tightened PC bar with 4,408 J impact energy at 50 °C and 0 °C, was investigated. A 3D Applied Element Method (AEM) model was developed for simulating asphalt pavement at 50 °C and 0 °C under 4,408 J impact energy. The numerical simulations were verified based on the experimental results. The numerical simulation results showed that the asphalt pavement system used in this study at 50 °C and 0 °C can withstand 4,408 J impact energy. Further, AEM numerical simulation with appropriate modeling demonstrated the effectiveness of an asphalt pavement system with appropriate material and thickness in preventing protrusion of PC bar.

Life cycle assessment of next generation non‐metallic bridges

AbstractEmployments of highly durable low carbon technologies are crucial for mitigation of climate change ensuring sustainable infrastructures. In this perspective, a challenging initiative for ultra‐high durability low carbon prestressed concrete bridges utilizing sustainable zero cement concrete (STC‐ZERO) and non‐metallic reinforcement is undertaken. STC‐ZERO exhibiting high strength, low shrinkage, and low creep reduces carbon emission up to 70% compared to the conventional concrete as cement is entirely replaced. Aramid fiber PC tendons have no factor of deterioration of concrete thanks to nonexistence of corrosion. Accordingly, an AASTHO‐PCI BT‐72 PC girder bridge and a butterfly web bridge are designed incorporating this combination and compared with corresponding conventional bridges with respect to whole life carbon emissions. Since there are no repair and rehabilitation requirements, the whole life carbon emissions of next generation non‐metallic bridges are expected to be reduced by around 70%.

Development of enhanced fiber beam element with multi-axial material constitutive models for reinforced/prestressed concrete beams

In order to consider the interactive behavior of flexure and shear, an enhanced displacement-based fiber beam element is developed by utilizing multi-axial material constitutive models for fibers, in particular, with the Modified Compression Field Theory (MCFT) for fibers representing concrete with smeared stirrups in RC/PC beams/girders. The potential shear-locking problem is avoided by adopting a mixed interpolation form with a bubble term for the displacement field, and the validity of the approach is verified by a classic example. The proposed element is first validated through a classic test series of shear-critical RC beams from the literature and then applied to a PC girder recently tested under both shear-critical and flexure-dominated scenarios. It is shown that the proposed element can be used to predict the structural behavior of RC beams and PC girders satisfactorily, after enhancing the conventional fiber beam element by considering the coupling of flexure and shear. In addition, the proposed element provides a tool to predict both flexure and shear capacities of concrete beams with adequate accuracy.

Experimental study on the effect of PC tendon rupture on load-carrying capacity of PC girder

Experimental study on the effect of PC tendon rupture on load-carrying capacity of PC girder

Load Carrying Capacity and Durability of PC Girder Using CFCC Tendon under Long-Term Exposure in Corrosive Salt Environment

Load Carrying Capacity and Durability of PC Girder Using CFCC Tendon under Long-Term Exposure in Corrosive Salt Environment

Regression-Based Adjustment Factor to Better Estimate Shear Capacity for Load-Rating Simple Span PC Girders

Regression-Based Adjustment Factor to Better Estimate Shear Capacity for Load-Rating Simple Span PC Girders

Long-term Application of Carbon Fiber Composite Cable Tendon in the Prestressed Concrete Bridge-Shinmiya Bridge in Japan

Carbon fiber reinforced plastic (Carbon Fiber Composite Cable, CFCC) has the outstanding features in comparison with regular steel. In October 1988, CFCC was applied as the tensioning material in main girders of new Shinmiya Bridge in Ishikawa, Japan. This was the first bridge in Japan and in the world, which CFCC tendons were used in the prestressed concrete bridge to counter salt damage. To investigate the serviceability and durability of the main girders and CFCC, three full-scale test girders were fabricated in 1988. At the same time, a bending experiment was conducted on one girder to investigate the ultimate behavior, load carrying capacity of the PC girder, as well the strain behavior of the CFCC. Besides, two PC girders were placed next to the main girders of the bridge in the same conditions. One of them was used for a destructive test after six years of the construction time (1994). In this study, another test specimen that was exposed to the actual corrosive environment after nearly 30 years was subjected to a destructive test by bending load. The load carrying capacity of the girder was clarified, and the durability of the PC girders using CFCC tendon was confirmed.

Effects of Fly Ash on Mechanical Properties of PC Girder Using Reac-tive Andesite Aggregates

Effects of Fly Ash on Mechanical Properties of PC Girder Using Reac-tive Andesite Aggregates

Structural health monitoring of maglev guideway PC girders with distributed long-gauge FBG sensors

Summary Health monitoring for maglev guideway PC girders is critical to ensure the safe operation of a high-speed maglev train. A long-gauge fiber Bragg grating (FBG) sensor has been recently developed to achieve the high-precision distributed macro-strain measurements and the capability of dynamic testing. This paper presents an integrated strategy for health monitoring of maglev PC girders equipped with the developed FBG sensors. Using the quasi-static measurements under the maglev train load that is uniformly distributed over the span, the deflection and the flexural stiffness of the PC girder can be evaluated. Using the dynamic measurements of the free vibration after the quick passing of the maglev train, the modal parameters of the girder is determined, based on which the flexural stiffness can be calculated in a different way. Using the long-term quasi-static measurements with no maglev train passing by, the deflection can be estimated due to the other effects such as temperature variation, concrete creep, or prestress loss. If assuming that the prestress loss is the only cause of the long-term deflection, the prestress loss can be determined according to its quantitative relation with the strain variation. Through analytical investigations and field testing on a typical maglev PC girder, the ability of the FBG sensors to evaluate the deflection, stiffness, modal parameters and prestress loss is validated.

Energy dissipation and absorption capacity influence on experimental modal parameters of a PC girder

This experimental investigation focuses on collecting vibration data after different loading scenarios in a PC girder while measuring the performance at the same time. The vibration data is used for modal analysis and since several samples were taken in each scenario with different impact hammer tips, a comparison of the outcomes is also possible. The performance is based on recorded displacements along the bottom surface of the girder, information that makes possible the calculation of energy absorbed before cracking and the energy dissipation that takes place after cracking. Furthermore, two major damage events, a tendon breakage and cracking, were induced and monitored respectively. This study also clarified the influence of change in energy on changes in modal parameters.

Productivity Improvement for a Prestressed Concrete Bridge by Using U-shaped PC Girder Shin Tomei Expressway

Productivity Improvement for a Prestressed Concrete Bridge by Using U-shaped PC Girder Shin Tomei Expressway

<b>Study on Application of Blast-furnace Slag Cement Concrete to PC Girders Based on Evaluation of Shrinkage and Creep</b>

The application of blast-furnace slag cement concrete (BC) to PC girders is one good method to prevent ASR; however, its shrinkage and creep have not been evaluated. This paper summarizes the result of the compression creep tests executed, and shows that the shrinkage and creep of BC can be evaluated through conventional equations, usually used for normal cement concrete (NC). In addition, the analysis results indicate that even if BC is applied, the deflection and prestress loss of PC girder differ only a little from that of NC.

Shear design of high strength concrete prestressed girders

Normal strength prestressed concrete I-girders are commonly used as the primary superstructure components in highway bridges. However, shear design guidelines for high strength PC girders are not available in the current structural codes. Recently, ten 7.62 m (25 feet) long girders made with high strength concrete were designed, cast, and tested at the University of Houston (UH) to study the ultimate shear strength and the shear concrete contribution (V c) as a function of concrete strength (f′c). A simple semi-empirical set of equations was developed based on the test results to predict the ultimate shear strength of prestressed concrete I-girders. The UH-developed set of equations is a function of concrete strength \((\sqrt {f'_c } )\), web area (b w d), shear span to effective depth ratio (a/d), and percentage of transverse steel (ρ t). The proposed UH-Method was found to accurately predict the ultimate shear strength of PC girders with concrete strength up to 117 MPa (17000 psi) ensuring satisfactory ductility. The UH-Method was found to be not as overly conservative as the ACI-318 (2011) code provisions, and also not to overestimate the ultimate shear strength of high strength PC girders as the AASHTO LRFD (2010) code provisions. Moreover, the proposed UH-Method was found fairly accurate and not exceedingly conservative in predicting the concrete contribution to shear for concrete strength up to 117 MPa (17000 psi).

A study on joint of composite steel girder and PC girder using shear connecting method

A study on joint of composite steel girder and PC girder using shear connecting method

Study on Dynamic Response Test of Long Span PC Girder Bridge under the Operating Conditions

In this paper, based on the Guangzhou Pazhou Bridge ,the acceleration and dynamic deflection was tested synchronously under normal operating conditions. Power spectral density analysis of the measured signal was done with frequency domain analysis methods.The measured value was compared with the finite element calculated value.The studies are as follows: first, the acceleration and deflection power spectral density function shows a multimodal distribution；the vibration frequency is concentrated in the low frequency range；the bridge vibration energy is concentrated in the first three frequency.Second, the actual operating conditions of Pazhou Bridge is good and it has a good bearing capacity. Third，the bridge impact coefficient measured maximum value is much greater than the national specification values.The researchs can provide the basic data for study on bridge health monitoring system development and bridge vibration signal separation technique.

Field measurements of traffic-induced vibration of straddle-type monorail PC girder viaducts

Field measurements of traffic-induced vibration of straddle-type monorail PC girder viaducts

PC 큰 보-PC 작은 보 접합부의 전단성능 평가

본 연구는 PC 작은 보의 댑단부와 PC 큰 보의 레져에 대한 전단성능을 평가하기 위한 전단 구조성능 실험연구이다. 일반적으로 작은 보의 댑단부와 큰 보의 레져는 사용하중에 안전하도록 설계하고 있지만, 작은 보의 단부를 연속단으로 설계한다면 작은보의 댑단부와 큰 보의 레져는 고정하중과 시공하중에만 안전하도록 설계할 수 있다. 이에 대한 구조성능을 평가하기 위하여 행거철근 정착방법, 설계하중, 레져보강근유무를 변수로 총 7개 실험체를 제작하여 전단실험을 실시하였다. 실험결과, 댑단부 및 레져가 <DL+CL>으로 설계되어도 작은 보의 연속성은 확보될 수 있는 것으로 나타났으며, 전단 임계단면은 지지점으로부터 유효높이(d)만큼 떨어진 위치에서 형성된 후 댑단부로 진전되었다. 그리고 PCI 핸드북에서 레져를 설계할 때 캔틸레버 슬래브와 같은 구조일 때로 해석하고 있는데, 본 공법에서의 레져는 3변 고정 슬래브와 같은 구조이므로 PCI 핸드북에서 정의하는 방법은 본 공법의 레져를 과대설계할 가능성이 있는 것으로 사료된다. The object of this study is to evaluate the structural shear capacity of the PC girder-PC beam joint. The dapped end of PC beam and the ledger of PC girder are usually designed to design load. If the end of PC beam can be designed with continuous end, the dapped end of PC beam and the ledger of PC girder do not need to resist to all loads except dead load and construction load. The experimental program was carried out with 7 specimens containing the variable factors as the anchored method of the hanger bar, design load, be or not exist of ledger bars. As a result, the continuity of the dapped end and the ledger were ensured their safety although the design load was only the dead load and the construction load. The shear critical section was expanded toward the effective depth d, the distance from the supported position of the beam. If the ledger is designed according to PCI Design Handbook, the structural system of the ledger is as to the cantilever slab system. But the ledger of this study is as to the 3 side fixed slab system. Therefore the design of the ledger by PCI Design Handbook will lead to highly conservative results.