Precast Segmental Construction Research Articles

Capacity assessment of segment-to-segment joints in precast unbonded segmental bridge decks under vertical seismic mainshock and aftershocks

Precast segmental construction of concrete bridge decks has become increasingly popular due to short construction time and low cost compared with other construction methods. However, during earthquake excitation the segment-to-segment joints in post-tensioned bridge decks may constitute a weak part of the superstructure, particularly due to the lack of continuous rebar that is present in cast-in-place decks. This research investigates the effects of the vertical component of earthquakes on the joints of the superstructure of bridges in near-fault regions. Specifically, a sample non-continuous precast segmental bridge with unbonded cables and constructed with the span-by-span method, has been studied using a detailed two-dimensional non-linear Incremental Dynamic Analysis (IDA) and Nonlinear Pushover Analysis (NPO). The results indicate that the vertical component of the earthquake could significantly adversely affect the joints’ behavior, especially in the upward direction. This may cause failure in the critical joints at midspan earlier than other common collapse prevention (CP) limit states such as deck sliding on the seat. The joint failure occurs easier in the mainshock-damaged bridge than in the intact one. Hence, the collapse probability can increase by up to 47% for the considered cases.

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.

Structural Safety Evaluation of Precast, Prestressed Concrete Deck Slabs Cast Using 120-MPa High-Performance Concrete with a Reinforced Joint.

Prestressed concrete structures are used in various fields as they can reduce the cross-sectional area of members compared with reinforced concrete structures. In addition, the use of high-performance and strength concrete can help reduce weight and achieve excellent durability. Recently, structures have increasingly been constructed using high-performance and strength concrete, and therefore, structural verification is required. Thus, this study experimentally evaluated the structural performance of a long-span bridge deck slab joint, regarded as the weak point of structures. The specimens were designed with a 4 m span for application to cable-stayed bridges. To ensure the required load resistance and serviceability, the specimens comprised of 120 MPa high-performance fiber-reinforced concrete and were prestressed. The deck slabs satisfied all static and fatigue performance as well as serviceability requirements, although they were thinner than typical concrete bridge deck slabs. The study also verified whether the deck slabs were suitable to help implement precast segmental construction methods. Finally, the results confirmed that the structural performance of the developed prestressed concrete (PSC) deck slab was sufficient for the intended bridge application as it achieved a sufficiently large safety factor in the static and fatigue performance tests, relative to the design requirement.

Precast versus cast in‐situ concrete in the construction of post‐tensioned box‐girder bridges: Span effect

AbstractIn this research, the effect of span and construction method on the designed cross section, construction time, and cost of box‐girder bridges has been explored. Two types of construction techniques used in bridges were investigated and compared: cast in‐situ post‐tensioned concrete and precast segmental bridge. To satisfy the aim of this work, the structural design was analyzed for different span lengths (40, 50, 60, 70, and 80 m) to evaluate the designed depth and required prestressing strands, and then design outcomes were utilized in estimating the construction duration and cost of cast in‐situ and precast segmental construction methods. Furthermore, the research has been extended to identify the impact of construction duration on the total cost of studied bridges. This investigation shows that the cost of a box‐girder bridge is affected by the span and the construction method where the precast segmental way was found to be less expensive.

Transverse analysis of full-scale precast segmental box girder segments with corrugated steel webs: Experimental tests and FE modelling

The world’s first full-scale model test of the precast segmental box girder with corrugated steel webs (CSWs) is carried out in this study to examine the applicability of using the precast segmental construction technology in erecting the composite girder bridges with CSWs. This study focuses on the transverse mechanical performance of bridge segments under vehicle loads; based on the fact the transverse bending stiffness of segmental box girders with CSWs is weaker than that of bridge girders with concrete webs. It is found from the experimental results that that bending failure of the top concrete flange occurs first instead of the shear buckling of the CSWs. In addition, the result of load testing indicate that the precast segmental box girder with CSWs has a high coefficient of safety margin and a good plastic deformability. This study also presents two improved schemes of structural design to enhance the structural transverse stiffness and reduce the accumulated deformation differences caused by the self-weight in the process of segmental precasting by the short-line method.

Seismic behavior of precast segmental UHPC bridge columns with replaceable external cover plates and internal dissipaters

A new earthquake resilient ultra-high-performance concrete (UHPC) bridge column was proposed and fabricated with precast segmental construction. The bottom segment was divided into two parts: core zone and four replaceable surrounding UHPC plates, between which replaceable dissipaters were employed. Rapid repair was completed with substitutions of damaged replaceable components, including UHPC plates and dissipaters, after an earthquake. Cyclic loading tests were conducted on three 1:3 scaled specimens and their corresponding repaired specimens. The research parameters included post-tensioning (PT) force level and usage of replaceable dissipaters. The test results showed that both the construction and repair times could be decreased owing to the use of proposed bridge column. The damage to replaceable dissipaters and cover plates was significant, but the damage to core concrete was minimal. The original repaired specimens presented displacement capacities of at least 5% and 4% drift, respectively. All specimens showed excellent self-centering and had less than 0.8% residual drift until failure. Two different failure modes were found: cover plate failure in lateral bending failure, which significantly reduced the lateral load, and dissipater coupler failure, which caused dissipaters to work inefficiently and decreased energy dissipation. Compared with the original specimens, which failed in the same failure mode, the repaired specimen had similar lateral load and displacement capacities, but a lower initial stiffness. All PT tendons were elastic and no yield or rupturing was found, but the stress loss was significant. The rotation of the bottom joint dominated the lateral deformation, and the contribution of joint sliding can be neglected.

Mechanical performance of statically loaded flat face epoxy bonded concrete joints

One of the main challenges in the offshore renewable energy industry is the reduction in the levelised cost of energy of wind, wave and tidal devices. The use of concrete as the primary construction material in such devices presents a low unit cost, high marine durability alternative to steel, however, to maximise material efficiency factors such as mix constituent design, structural detailing and manufacturing processes have to take into account the specific conditions of the marine environment. Pre-cast segmental construction can be considered as one of the fastest and cheapest construction options. However the challenges regarding performance of epoxy bonded concrete in marine environment should be taken into account. This paper presents the results of an experimental programme on the performance of shear and tensile capacity of flat face concrete joints, focussing on the effect of substrate surface preparation, joint thickness, properties of epoxy resins, exposure to seawater and presence of joint defects on the ultimate failure load. The ultrasonic pulse velocity (UPV) method for detection of defects in the adhesive layer was examined and digital image correlation is used to observe the surface strain flow through the joint. The results indicate that the epoxy joints behave monolithically and remain undamaged under different types of static loading. The joints do not significantly interrupt the flow of strain but can locally affect the distribution of strain (and thus stiffness and stresses) in a structure. An increase in the density of the epoxy (and the filler content) leads to the increase in the joint strength and thicker joints are less affected by small defects in the bonding layer. The majority of tested specimens failed by cracking of concrete rather than by debonding of the joint, whilst compressive stresses acting on the joint can help to augment its shear strength. Sandblasting of bonded surfaces can improve performance of joints, whereas UPV testing may be used for quality control of epoxy-bonded joints.

Cyclic response of a precast composite hollow reinforced concrete column using longitudinal rebars and base plate

In this research, the precast segmental construction of composite hollow reinforced concrete (RC) columns was studied. The precast segmental construction of composite hollow RC column requires guidelines for the connections between the bent cap and column segment, connections between column segmental joints, and connections between column segment and footing. The connection methods for different precast composite hollow RC piers were experimentally studied for rational resistance against shear force and bending moments. Two types of precast composite hollow RC columns and cast‐in‐place column were studied in this paper. The performance of these columns was evaluated through experiments. The precast column erected with a base‐plate connection exhibited a performance similar to the cast‐in‐place column.

Prestressing Optimization and Local Reinforcement Design for a Mixed Externally and Internally Prestressed Precast Segmental Bridge

The precast segmental construction is advantageous for rapid erection, high quality of concrete segments, and minimal disturbance to traffic. This paper compares two different tendon layouts of a segmental bridge erected by the span-by-span method. These comparisons include the stress analysis based on the 14-degrees of freedom (DOF) spatial beam model that considers warping, construction speed, and constructability. A simplified two-dimensional (2D) planar model for the reinforcement design of a rib deviator was proposed. The tensile stress region method (TSRM) was applied in the reinforcement design of the diaphragm in this type of bridge; thus the original reinforcement design was optimized, which can be useful in the design for structures of the same type.

Effect analysis of an arc-strike-induced defect on the failure of a post-tensioned threadbar

A temporary threadbar used for precast segmental construction broke during the post-tensioning stage before reaching the service load. Failure analysis showed that the premature failure of the bar was due to the presence of an arc strike. The arc strike effects on the material and threadbar integrity are considered.

An Experimental Study on the Behavior of Shear Keys According to the Curing Time of UHPC

Precast segmental construction has been recently developed to reduce the construction cost and shorten the construction term as compared to the cast-in-place method in a will to establish the design and erection system of structures using Ultra High Performance Concrete (UHPC). However, this method requires the presence of segmental joints to transfer the loads between neighboring segments, which stresses the importance of securing structural safety and serviceability. Therefore, need is for research on the behavior of the segmental joint for the structures erected by the precast segmental construction method. To that goal, this paper presents an experimental study on the behavior of shear keys with respect to the curing time of UHPC in the segmental joint. Analysis is done on the load-displacement relation according to the curing time of the shear keys and on the failure modes of the shear keys according to the cracking pattern at failure.

Discussion of “Equivalent Unbonded Length for Modeling of Multistrand Tendons in Precast Segmental Construction” by Marc J. Veletzos and José I. Restrepo

Discussion of “Equivalent Unbonded Length for Modeling of Multistrand Tendons in Precast Segmental Construction” by Marc J. Veletzos and José I. Restrepo

MIDAS-Based Finite Element Analysis of the Short Line Method of the Precast Segmental Bridge Construction

This paper studies the precast and cantilever erection process of pre-stressed concrete continuous beam bridge alignment control in short line method, basis on the construction of a light rail. Various stages of bridge construction performed on simulation analysis and calculated by the finite element software MIDAS, concluded the ultimate internal force and deformation values, and the maximum deformation are within the scope of design elevation deviation 20 mm allowed, as to achieve the target of bridge assembly.

Equivalent Unbonded Length for Modeling of Multistrand Tendons in Precast Segmental Construction

Recently issued seismic design guidelines for precast segment construction require nonlinear modeling of segment-to-segment joints of important bridges. The response of segment joints is highly dependent on the length of debonding of the multistrand tendon. Neither the seismic design guidelines nor the literature provide sufficient guidance on how to determine the equivalent unbonded length of such tendons. This paper presents key results and conclusions of a large-scale experimental research program that investigated the debonding characteristics of multistrand tendons. Results indicate that tendon slip relative to the grout is small in comparison with slip between the duct and the surrounding concrete. An equation to evaluate the equivalent unbonded length of multistrand tendons was developed with direct application to modeling of the segment joint response.

Challenges in Bridging Indian Rivers

The Indian subcontinent has been gifted with several major rivers, most of them meeting either the Arabian Sea or the Bay of Bengal. Constructing bridges across major rivers and creeks has been a challenge in view of the large flood plains, deep scour of river beds, bank erosion, etc.Long-span bridges with caisson foundations have been the preferred choice for major river/creek bridges in view of the high cost of the foundations. The foundations of these bridges are usually very deep and the construction proceeds at a relatively slow pace, with an element of uncertainty in the time required for completion. With better equipment and corresponding quality control, construction of large-diameter pile foundations has emerged as a faster and reliable option. Developments in pre-cast segmental construction have also contributed to a gradual shift in the preferred span and foundation type to ensure much shorter construction periods.This paper presents a brief history of the landmark bridges constructed across the major rivers in India and also discusses the present scenario and engineering challenges in bridging Indian rivers, including a case study.

Eugène Freyssinet—Invention of Prestressed Concrete and Precast Segmental Construction

It is well known that Eugène Freyssinet was the inventor of prestressed concrete. However, it is not as well known that he was a skilled craftsman and a prolific bridge builder, qualities that prepared him to invent prestressed concrete. After graduating in 1905, Freyssinet built a number of concrete arch bridges, each of which successively broke his own world record for span length. This enabled him to develop an appreciation for creep of concrete, and encouraged him to develop high quality concrete and high strength steel that were necessary for the invention of prestressed concrete in 1928. His spectacular rescue of the Le Havre Maritime Station in 1934 was the first practical application of his prestressing devices and instantly earned him a worldwide reputation. One of the more profound contributions of Freyssinet is the invention of precast segmental construction, which started with his structures of the Luzancy Bridge lineage in the 1940s, and to this day allows concrete bridges to remain competitive with steel bridges. This paper commemorates the 50th anniversary of his passing in 1962 by describing the journey taken to create an “entirely new material” that led to a “revolution in the art of building”.

Analysis of segmental piers consisted of concrete filled FRP tubes

Precast segmental construction technique is an excellent candidate for economic rapid bridge construction in highly congested urban environments and environmentally sensitive regions. This paper presents three dimensional nonlinear finite element models using ABAQUS⧹Standard for evaluating the behavior of segmental precast post-tensioned piers under lateral loads. The piers were constructed by stacking precast concrete filled fiber reinforced polymer tube segments one on top of the other and then connecting the assembly structurally with vertical post-tensioning tendons passing through ducts located in the precast segments. A stress–strain relationship for confined concrete was used to model the concrete. The post-tensioning tendons were modeled with beam elements. The model was able to predict the backbone curves for two piers subjected to cyclic loads. A parametric study indicated that increasing the applied post-tensioning force increases nominal strength. Finally, the model showed that the pier aspect ratio, cross sectional diameter size, pier size, and confinement have significant effects on the performance of the investigated piers.

Numerical Analytical Model for Seismic Behavior of Prestressing Concrete Bridge Column Systems

Conventional bridge seismic design practices depend on the ductility capacity of bridge columns. However, damaged columns tend to produce large residual deformations following a seismic event due to the formation of a flexural plastic hinge. Improved seismic response can be realized through the use of unbonded post-tensioning prestressing cast-in-place (CIP) column systems or precast segmental column systems. These bridge column systems can produce significantly less residual displacements when compared to a traditional concrete column. Moreover, precast segmental construction can also significantly reduce construction time and minimize construction cost of bridges in highly congested urban environments. Therefore, one research thrust area of bridges is the seismic performance of prestressing CIP reinforcement concrete columns and prestressing precast segmental column systems which were investigated through quasi-static, shake table test and numerical analyses. However, numerical analytical models which can allow for major nonlinear factors of prestressing concrete bridge column systems are not available yet. This paper presents the numerical analytical models which can be easily carried out in the structural analysis software for seismic response of prestressing CIP reinforced concrete and precast segmental bridge column systems. The numerical analytical model consists of segment model, prestressing tendon model and joint model. Segment model is modeled by nonlinear fiber beam-column elements which sophisticated constitutive models are used to simulate the non-linear cyclic behavior of the concrete, reinforcement steel and bonded prestressing tendons. Unbonded prestressing tendons is modeled by “tension-only” bilinear cyclic truss elements, each node of the truss is laterally constrained to the adjacent segmental element node. A group of zero-length element with “compression-only” nonlinear hysteretic springs which allows for damage expected at the segmental joints and gap element is used to model segment-to-segment joints.

Modeling of Jointed Connections in Segmental Bridges

Precast segmental construction of bridges can accelerate construction and minimize the cost of medium span bridges in environmentally sensitive and difficult to access locations. Despite these benefits, the use of precast segmental bridges in seismic regions of the United States remains limited. A main obstacle to their use is concern regarding the seismic response of segment joints. Recent experimental research programs studied the seismic performance of segmental superstructures. However, an estimate of the seismic response of full-scale segmental bridges to real earthquake records remains unknown. This paper presents a segment joint modeling approach and is an important first step toward accurately estimating the seismic response of superstructure segment joints to input ground motions. The approach is a compromise between the detailed and computationally intensive continuum mechanics based finite element approach and a simple approach that models the joints with rotational springs. The approach considers the nonlinear tendon-grout slip response and was validated with data from large-scale experiments. Numerous modeling sensitivity studies were performed and recommendations for implementation in full-scale models are presented.

Seismic Behavior of Posttensioned Concrete-Filled Fiber Tubes

Precast segmental construction technique is an excellent candidate for economic rapid bridge construction in highly congested urban environments and environmentally sensitive regions. This paper presents the seismic behavior of four hybrid segmental columns consisting of precast posttensioned concrete-filled fiber tubes (PPT-CFFTs). A fifth monolithic column was also tested as a reference specimen. The columns were tested under increasing lateral loading cycles in a displacement control. The columns had circular cross section diameters of 203 mm and heights of 1,524 mm each. The parameters investigated included different construction details and energy dissipation systems. The PPT-CFFT columns developed lateral strength and deformation capacity comparable to those of the monolithic reinforced concrete column. However, the PPT-CFFT columns dissipated smaller hysteretic energy compared to that of the monolithic reinforced concrete column. Finally, a simple model was used to predict the backbone curves of se...