Precast Concrete Beam-column Connections Research Articles

Experimental research on seismic performance of dry-wet combined precast concrete beam-to-column connections

In order to enhance on-site assembly efficiency and construction organization flexibility, a new type of dry-wet combined precast concrete beam-column connection was proposed. The prefabricated beams and columns were joined together using local post-tensioned tendons to create a temporary frame structure with dry connections. Subsequently, the wet connections between the prefabricated beams and slabs were established by pouring cast-in-place top concrete. A monolithic connection and four full-scale precast connections were subjected to reversal cyclic loading, with each designed incorporating distinct types of post-tensioned (PT) tendons, bonding conditions, and grouting materials. The test results indicate that the new connection exhibits flexural failure at the beam ends. In comparison to cast-in-place connections, it demonstrates enhanced deformation capacity, comparable ductility, higher stiffness, and reduced energy dissipation due to slippage of the PT tendons and steel bars. However, the viscous damping exceeds 15 %, thereby satisfying the seismic resistance requirements. The high-strength mortar grouting material satisfactorily fulfills the anchoring requirements of steel bars within the corrugated steel ducts, whereas the prestressed grouting material falls short in this regard. The overall performance of the new connection can be further enhanced by improving the grouting material and implementing local unbonded measures.

Hysteretic Behavior of Full-Scale Precast U-Shaped Composite Beam–Column Connections with Large-Diameter Reinforcements under High Axial Compression

This study introduces precast concrete beam–column connections comprised of composite beams, precast columns, and a monolithic joint core. The composite beams consist of U-shaped beams and floor slabs, leveraging the U-shaped beams for their lightweight nature, acceptable stiffness, and reduced demand for on-site support systems. To mitigate reinforcement congestion in the joint core, the precast connections incorporate large-diameter rebars (greater than 25 mm). This study conducted cyclic loading tests on four full-scale beam–column connections under 0.3 normalized compression, encompassing precast interior and exterior connections, along with two monolithic reference specimens, to investigate their behavior under seismic actions. The results revealed that all specimens exhibited bending failure at the beam ends, with minimal concrete deterioration observed in the joint core areas and columns. The hysteresis curves of the precast specimens and the monolithic connections exhibited a slight pinching effect. The strengths of the interior and exterior precast specimens were 13.3% and 7.8% lower than those of the reference monolithic connections, respectively. The ductility of interior precast connections and monolithic specimens stood at 2.36 and 2.23, respectively, indicating a negligible difference of less than 5%. Meanwhile, the positive and negative ductility of exterior precast connections were 3.06 and 2.34, which was approximately 8% lower than that of the reference connections. Furthermore, the stiffness degradation and energy dissipation capacity of the precast specimens aligned closely with the performance of the reference monolithic ones.

An investigation and design of novel moment-resisting beam-column connections for precast concrete construction

This study investigates the behavior of hybrid beam-column connections with numerous detailing methods to be incorporated into precast concrete moment-resisting frames under simulated reversed cyclic loading, and ultimately develops a design procedure. Seismic performance of moment-resisting precast concrete beam-column connections was investigated through simulated reversed cyclic load tests. In addition, nonlinear finite element analysis (FEA) of typical monolithic and precast concrete connections was carried out using a modified concrete damage plasticity model. Good agreement was achieved between experimental and numerical results, which indicates that the FEA model is capable of capturing failure modes of the investigated precast concrete connections. Simple detailing modifications resulted in major improvements in the performance of connections in terms of load-displacement curves, stiffness, and energy dissipation. Finally, a design procedure was developed for the investigated connections based on failure modes and investigated limit states.

Cyclic loading response of precast concrete beam-column connections with partially bonded draped prestressing tendon

An emulative precast concrete beam-column connection consists of prefabricated columns, T-shaped composite beams with partially bonded post-tensioned (PT) tendon, and cast-in-place (CIP) core region is proposed in this study. Experimental study was carried out to examine the hysteretic behavior of four full-scale beam-column connections under a high axial compression ratio (μ = 0.4). The specimens included a precast interior connection (PC1), a precast exterior connection (PC2), and two corresponding conventional CIP control specimens (RC1 and RC2). Performance assessment of the suggested connection was conducted by evaluating various factors, including failure mode, hysteresis curve, deformation, stiffness, and energy dissipation capacity. Test results revealed that all specimens fulfilled the design objective of strong column-weak beam with flexural failure showed at beams ends. In comparison to RC1, PC1 exhibited a 6.4 % increase in peak load-carrying capacity in the positive loading process and a 7.1 % decrease in the negative loading process. On the other hand, PC2 demonstrated approximately 11.9 % higher load-carrying capacity in the positive loading and a 2.0 % lower capacity in the negative loading when compared to RC2. The ductility coefficients of PC1 and PC2 was 3.39 and 2.64, respectively, which were slightly higher than that of RC1 and RC2 (3.01 and 2.43). All specimens exhibited good deformation restoring capacity and plump hysteretic loops, demonstrating satisfactory energy dissipation capacity. Overall, the proposed connection with partially bonded PT tendon showed comparable seismic performance with their CIP counterparts, indicated its promising potential for use in practical engineering applications.

Seismic behaviour of precast concrete beam-column connections with bolted end plates

This paper presents the seismic behaviour of a dry beam-column connection with bolted end plates for precast concrete structures. Experimental tests were carried out on one cast-in-situ connection and three precast concrete connections with bolted end plates to study the behaviour under reversed cyclic loading. The load resistance, failure mode, ductility and energy dissipation capacity were determined from experimental results. Comparisons were made among different connections to show the influence of end plates and stiffeners on the connection behaviour. Test results showed that precast concrete connections with bolted end plates mainly dissipated energy through bending of the end plate and deformation of steel bolts. The final failure of connection resulted from the yielding of the end plate or crushing of concrete in the compression zone of beams, depending on the thickness of the end plate and the presence of stiffeners. The connection with bolted end plates could achieve good ductility and energy dissipation. Moreover, failure of columns and the joint core was prevented through the use of end plates. An analytical method was also proposed to evaluate the moment-rotation relationship of connections. The contributions of joint core, steel bolts and the end plate to rotational stiffness and moment resistance were quantified in the analytical method. Comparisons with test results showed that the analytical method can estimate the moment-rotation curve of connections with bolted end plates with good accuracy when failure of connection was dominated by steel bolts or the end plate. Design recommendations were also proposed for connections with bolted end plates.

Seismic Performance Evaluation of Dry Precast Concrete Beam-Column Connections with Special Moment Frame Details

Seismic Performance Evaluation of Dry Precast Concrete Beam-Column Connections with Special Moment Frame Details

Cyclic behavior of a slit damper proposed for precast concrete beam-column connections

Since the 2017 Puebla-Morelos Earthquake, interest in limiting damage to structural components has exponentially increased in Mexico. Consequently, the use of energy dissipation devices has received renewed attention. Following that line, this paper studies an attractive solution, which is a slit damper proposed as a passive energy dissipation device for, but not limited to, precast beam-column connections. Slit dampers have been studied for their cost-effectiveness and ease of application. They present stable hysteretic behavior and dissipate substantial amounts of energy under cyclic loading while maintaining less ductile elements essentially elastic. The structural behavior of the proposed device was evaluated theoretically, followed by experimental verification. Quasi-static incremental and constant-amplitude cyclic tests were conducted on eight specimens, with two of them having non-uniform struts. Test results are presented and discussed, emphasizing ductility and energy dissipation capacity. The proposed damper showed stable hysteretic behavior and adequate seismic performance. Using non-uniform struts significantly increased the damper's deformation capacity and fatigue performance, which is desirable for seismic zones where long-duration earthquakes are expected, such as in Mexico City. Numerical modeling techniques were also validated with finite element analyses. It was shown that the proposed damper's hysteretic response could be accurately predicted using the combined non-linear isotropic and kinematic hardening model.

Seismic Performance of Precast Concrete Frame Beam-Column Connections with High-Strength Bars.

As the construction industry is striding towards the industrialization of green buildings, a precast concrete frame beam-column joint with high-strength reinforcement was proposed. Simulate reversed cyclic loading was carried out on two precast connections and one cast-in-place connection to examine the seismic behavior of the proposed new precast connection. The main test variables between the two precast connections were the strength of the reinforcement at the bottom of the beam. The failure shape, hysteresis curve, skeleton curve, strength, deformation ability, stiffness degradation, and energy dissipation were monitored and compared with the cast-in-place connection. The findings of this paper showed that the precast joints had good strength reserve, and the seismic performance in the later stage of loading even exceeds the cast-in-place joints. It was also found that the plastic hinge zone of the beam could be moved away from the column surface via reinforcement method. Additionally, based on the experiment, a detailed nonlinear finite element analysis (FEA) method was developed to reproduce the test response of specific types of bending moment-resistant precast concrete beam-column connections under a reversed loading test, which provided a theoretical reference for further research of the connections.

Experimental Study on Seismic Behavior of Precast Bolt-Connected Steel-Members End-Embedded Concrete (PBSEC) Beam-Column Connections

With the rapid development and research of precast concrete frame structures, it is not difficult to find that the structural form and seismic performance of dry-connected precast joints have always been the focus of research. Since this type of structural system is complex, the construction is inconvenient in practical application, and many additional parts need to be installed, this paper develops a kind of precast bolt-connected steel-members end-embedded concrete (PBSEC) beam-column connection to solve the shortcomings of the current dry-connected precast joints. There is no wet work in the assembly process, and all-dry construction and assembly methods are used. There is no need to pour concrete and support formwork, which significantly improves construction efficiency compared to wet and cast-in-situ connections. Low cyclic reversed loading tests were conducted to obtain test data, such as failure mode, hysteresis curve, skeleton curve, stiffness, ductility, and deformation capacity of the precast concrete joint. The failure mode of the PBSEC joints is the buckling failure of the connecting steel plate, leading to a perfect seismic capacity and collapse resistance of the structure. The hysteresis curves of the PBSEC joints are bow-shaped and full in shape, showing high energy dissipation capacity. The bearing capacity of the joints begins to rise rapidly at the initial loading stage and then decreases slowly after reaching the peak, which is an ideal shape. By summarizing the average peak load, strength degradation coefficient, loop energy per cycle, loop energy per level, and cumulative energy damping coefficient, it is found that the joint using 10 mm thick Q235 steel can obtain the most suitable failure mode and obtain the best energy dissipation performance. When the strength of the steel plate material increases, the energy dissipation performance of the joint drops.

Experimental Study of Emulative Precast Concrete Beam-to-Column Connections Locally Reinforced by U-Shaped UHPC Shells.

Precast beam–column connections act as vital elements of precast concrete frames. To enhance the resistance to the earthquake-induced damage and environment-induced deterioration of precast beam–column connections, an innovative precast concrete beam-to-column connection locally enhanced by prefabricated ultra-high-performance concrete (UHPC) shells was proposed. For studying the seismic behaviors of these novel connections and the influence caused by the prefabricated UHPC shell length, full-scale precast specimens were experimentally investigated using low-cyclic reversed loading tests. The obtained results were analyzed and discussed, including hysteresis curves, skeleton curves, strength and deformability, performance degradation, energy dissipation capacities, and plastic hinge length. The results reveal that the novel precast concrete beam–column connections with UHPC shells behaved satisfactorily under seismic loadings. The damage in the concrete near the lower part of the beam end is reduced by the prefabricated UHPC shells. The longer prefabricated UHPC shells were more useful for decreasing the damage to the precast concrete components and improved the structural performance. The precast specimen with 600-mm long UHPC shells can achieve a ductility of 4.87 and 4.0% higher strength than the monolithic reference specimen.

Experimental study on two innovative ductile moment-resisting precast concrete beam-column connections

The use of precast concrete elements in construction leads to increased output quality, better product control, cost savings, and reduced construction time. The main problem of precast concrete structures is the improper performance of connections under lateral loads. In the present study, the aim is to improve the behavior of precast connections under cyclic loading. Two new beam-column precast connections with steel profiles as corbel with high-strength bolt fasteners are developed. Those connections have been designed to be used in intermediate moment frames in regions with high seismic risk. The advantage of these connections is the elimination of the need for remarkable concrete formwork, temporary supports, and low demand for in-situ concrete during construction and providing the possibility of construction progress on the floors in parallel. For studying the seismic performance of proposed connections, six specimens including four precast and two monolithic connections with different rebar ratios were made. The specimens were subjected to a horizontal displacement-control cyclic loading to obtain the load-displacement curves. The maximum lateral strength, ductility, strength degradation, stiffness reduction, and energy dissipation of precast connections were evaluated and compared with the in-situ connections. The ultimate strength and ductility of the precast connections were similar to the in-situ specimens, and proposed connections showed good cyclic behavior. The strength degradation and stiffness deterioration of precast connections were more than the in-situ connection, and the energy dissipation of them was less than monolithic connections. According to the analysis results, the performance of the proposed connections is acceptable and satisfies the criteria of the connections for use in areas with high seismicity.

Cyclic behaviour of precast beam-to-column connections: An experimental and numerical investigation

The main objective of this study is to examine the behavior of hybrid beam-column connections with numerous detailing methods to be incorporated in precast moment resisting frames under simulate reversed cyclic loading, which will lead to better understanding of their performance and safer seismic applications. To accomplish the research objectives, an integrated experimental and numerical study was conducted. The experimental part consisted of reversed cyclic loading of precast concrete beam-column specimens with six different anchorage details used in beam element, as well as monolithically cast companion specimens. In the numerical part, a nonlinear finite element analysis (FEA) approach was proposed to reproduce the experimental response of a specific type of moment resisting precast concrete beam-column connection exposed to reversed cyclic load tests. To prove the validity of the proposed finite element approach, three-dimensional (3D) finite element models were built using ABAQUS, a nonlinear finite element analysis tool, for a reference monolithic and various precast hybrid beam-column connections. The models intend to lead to comprehensive investigation of concrete and steel behavior reaching failure. A modified Concrete Damage Plasticity model (CDP) that accounts for compression-softening and tension-stiffening effect was adopted for concrete in order to reproduce the typical cyclic behavior of cracked reinforced concrete. Kinematic Bilinear Elasto-Plastic nonlinear model was used to model all steel parts with the addition of bond-slip effect for all reinforcing bars embedded in concrete.Good comparison between finite element results and tested members has been achieved, which demonstrates the accuracy of the proposed finite element model despite the complexity of the investigated connections. All failure modes of the precast connection components were captured from the developed finite element model and compared with those of the corresponding monolithic connection. It was observed that simple detailing modifications highly influence failure modes of the connections and may result in major improvement of the connection performance in terms of strength and energy dissipation mechanism. This study concludes that precast connections have the potential to perform well under cyclic loading and results from this study can be utilized to efficiently investigate the influence of various design parameters on these connections’ performance.

Experimental study on the seismic performance of new precast concrete beam-column joints with replaceable connection

To improve the seismic performance of precast concrete beam-column joints and facilitate rapid repair during post-earthquake, a novel type of dry precast concrete beam-column connection with multi-slit devices (MSDs) is proposed in this paper. To investigate the seismic performance of the proposed precast joint, three full-scale specimens were tested under cyclic loading, including two precast exterior beam-column joints and one cast-in-place concrete joint. The seismic behavior of the precast and cast-in-place joints was investigated and compared in terms of failure mode, strength, initial stiffness, hysteretic behavior, energy dissipation and deformation capacity. The test results show that the seismic performance of the precast beam-column joints is superior to the cast-in-place joint in terms of load-carrying capacity, stiffness, energy dissipation and deformation capacity, and the precast beam and column components are basically kept within the elastic range during the entire loading process. Therefore, the precast beam-column joint proposed in this paper can provide a good choice for the application of prefabricated concrete structures in high-risk earthquake regions. Furthermore, a simplified mechanical model of the precast beam-column joint is proposed, which will lay a foundation for the simulation and analysis of the seismic performance of this kind of prefabricated structures.

Energy dissipation capacity of precast concrete beam-column joint connected by double notch subjected to cyclic lateral loading

This paper presents the experimental investigation of full-scale precast concrete beam-column connections subjected to cyclic lateral loading. The specimen consists of three models. Two of which are precast beam-column connections and one is monolith. The precast and monolith specimen were designed for the same strength. The cross-sectional dimensions of the beam 250 mm x 300 mm and column 300 mm x 300 mm. Connections are placed in plastic hinge area, with a distance of h (beam height) from the face of the column which is expected to occur first destruction. Precast construction joints are distinguished, with 3 different models, namely monolith, double notch type 1 (STR-1), and double notch type 2 (STR-2). Maximum load capacity, hysterical behavior and energy dissipation are measured, and capacity is compared. The results showed that beam-column joint STR-2 are better able to absorb energy than beam column joint monolith and beam-column joint STR-1. Kumulative energy dissipation of monolith about 9333.07 kN-mm, STR-1 is 8336.76 kN-mm, and STR-2 is 10162.52 kN-mm. The use of dual notch connections (STR-1 and STR-2) provides satisfactory performance, which is marked by meeting the minimum relative energy dissipation ratio at a 3.5% drift according to the ACI Committee 374.1-05. The results show that the STR-2 beam-column connection is more capable of absorbing energy than the monolith beam-column connection and STR-1 beam connection. the value of monolithic cumulative energy dissipation is around 9333.07 kN-mm, STR-1 is 8336.76 kN-mm, and STR-2 is 10162.52 kN-mm. in principle, all three test specimens, monoliths, STR-1 and STR-2 provide satisfactory stability performance under lateral cyclic loads, because they still meet the minimum relative energy dissipation ratio at a deviation of 3.5% according to the ACI Committee 374.1 -05

Performance of a moment resisting beam-column connection for precast concrete construction

Seismic performance of a specific type of moment resisting precast concrete beam-column connection was investigated through reversed cyclic load tests. Structural steel components were incorporated with precast concrete beam and column elements in the experiments to provide a ductile moment resisting connection. Additionally, nonlinear finite element analysis (FEA) of typical monolithic and precast connections was performed to investigate the performance and failure modes of these connections. Concrete Damage Plasticity (CDP) model was used to capture nonlinearities in concrete under cyclic loading. Good agreement was achieved between experimental and numerical results, which indicates that the finite element model is capable of capturing failure modes of the investigated precast connections. Agreement between the experimental and numerical behaviors was valid in terms of both the global load–displacement response as well as the local response, such as the force within connection rods and the beam curvature. Behavior of the precast concrete connection was influenced significantly by the anchorage detail used for steel connection plates and the beam reinforcement detailing in the vicinity of the connection. Simple detailing modifications resulted in major improvements in the performance of connection in terms of strength, stiffness and energy dissipation characteristics.

Experimental investigation on hysteretic performance and deformation patterns of single-side yielding precast concrete beam–column connection with energy dissipation bars

With the aim of achieving high construction efficiency, satisfactory seismic performance, and rapid restoration of structural functionality after an earthquake, this study proposes an innovative single-side yielding beam–column connection with replaceable energy dissipation bars (REDB-SYBC) for precast concrete moment-resisting frames (PCMF). During assembly, the concrete beam is attached to a column via the connection function of a non-slipping threaded sleeve assembly (NSTSA) and the support action of the shear keys (SKs) in the REDB-SYBC. This reduces the need for temporary supports for the precast beams on site. Five large-scale tests on precast concrete connections considering the partial flange effect of a slab subjected to quasi-static cyclic loading were conducted to investigate the mechanical behavior, deformation patterns, and energy dissipation (ED) capacity. The primary experimental variables included different loading protocols, restrainer forms, ED segment areas, and whether to replace the ED bars. This paper presents the assembly construction and load-carrying mechanism, and the analysis of the experimental results, including the observations, hysteretic performance, and deformation patterns. The single-side yielding deformation pattern of the REDB-SYBC connection minimized the deformation of the adjacent floor slabs and magnified the deformation of the ED bars at the bottom of a beam, thus facilitating deformation compatibility with the floor system and causing the damage to be focused on the ED bars. Consequently, the five specimens exhibited similar failure patterns via the fracture of the ED bars due to low-cycle fatigue failure, which was attributed to extensive yielding in both tension and compression. The REDB-SYBC connections exhibited a distinct beam end yielding mechanism, which demonstrated a failure pattern that was consistent with the desired “strong column and weak beam” design philosophy. The test results indicated that the proposed REDB-SYBC connection exhibited a dependable decoupled moment and shear load transfer mechanism, stable hysteretic behavior, negligible beam elongation, and reduced floor damage. The performance of a repaired specimen was nearly the same as its counterpart before repair, indicating that replacement was effective. The impact on the REDB-SYBC connection in response to a strong aftershock was also estimated by reloading an unrepaired specimen.

Experimental investigation of a single-yielding precast concrete beam–column connection with replaceable energy-dissipation connector

A single-yielding mechanism can effectively control the bending moment of a connection, and reduce the damage to the connection and column. In this study, a single-yielding precast concrete (SYPC) beam–column connection with a replaceable energy-dissipation connector (REDC) is proposed. The force transfer mechanism of the SYPC connection is discussed based on theoretical research. To verify the force transfer mechanism and repair ability of the SYPC connection and investigate the seismic performance of the SYPC connection, five low-cycle quasi-static loading tests are conducted on a single full-scaled specimen using five REDCs with different sizes. According to the test results, the seismic performance of the SYPC connection is discussed, including the bearing capacity, energy dissipation capacity, and stiffness. In addition, the single-yielding mechanism, neutral axis depth, beam elongation, and REDC strain in the SYPC connection are studied. The analytical and test results show that the structure of the SYPC connection is simple and reasonable, and that the path of the force transmission is direct and efficient. The SYPC connection provides excellent seismic performance, and is easy to repair after an earthquake. The single-yielding mechanism allows for control of the bending moment of the SYPC connection; this is beneficial to avoiding damage to the connection, e.g., damage owing to the overstrength of the beam strength and the alteration of the strength hierarchy in the structural system. Thus, it is conducive to realizing the design concept of “strong-column and weak-beam."

Cyclic behavior of precast concrete beam-column connection using steel fiber reinforced cast-in-place concrete

Abstract Three equivalent exterior precast concrete beam-column (PCBC) connections have been investigated in this study in orderto analyze the effect of steel fiber reinforced concrete (SFRC) as cast-in-place (CIP) on the seismic performance of the PCBC connection. The connection was designed as a ductile connection for a moment-resisting frame and consists of a precast U-beam, precast column with corbel, interlocking bars, and CIP-concrete to connect the precast beam to precast column. The volume fractions of steel fiber incorporated within the CIP-concrete were 0%, 0.5% and 1%. A quasi-static load was applied vertically to the beam tip of the PCBC specimen. The results showed that the steel fibers contained within the CIP-concrete provided 2% increase of the maximum load, 17.7% increase of the energy dissipation, and increase in the joint stiffness of the PCBC connection. The steel fibers delayed the onset of cracking and slowed down the crack propagation, resulting in shorter cracks in the joint core of PCBC specimen, which correlates well with the deflection-hardening characteristic found from the modulus of rupture test.

Seismic performance analysis of a novel demountable precast concrete beam-column connection with multi-slit devices

In this paper, a novel type of precast concrete beam-column connection based on the ideal plastic hinge failure mechanism is proposed. This connection mainly includes a hinge shaft and multi-slit devices (MSDs). In order to investigate the seismic performance of the proposed precast concrete beam-column joint, the theoretical calculation method of MSD was first proposed, and its accuracy was verified based on the finite element (FE) analysis. Then, based on the proposed calculation method, two kinds of MSDs were designed to connect the precast concrete beam-column joint. The seismic performance of the precast joints was analyzed by FE models, and compared with the monolithic joint. The analysis results indicate that the seismic performance of the proposed precast beam-column joint is superior to that of the monolithic joint in terms of strength, stiffness, deformation, and energy dissipation capacity. Meanwhile, the MSD can be replaced after damage in earthquakes, which is convenient for rapid repair of prefabricated structures. Overall, the proposed precast beam-column joint shows excellent seismic performance and repairability. Therefore, the proposed beam-column connection method can provide a reference for the application of prefabricated structures in high seismic intensity regions.

Seismic performance of concrete-filled steel tube devices for precast concrete beam-column connections

Seismic performance of concrete-filled steel tube devices for precast concrete beam-column connections