Composite Coupling Beams Research Articles

Seismic behavior of plate‐reinforced composite coupling beams with steel bar truss deck

SummaryTo better meet the evolving requirements of industrialized building system, this paper introduces a novel approach by proposing the utilization of a plate‐reinforced composite (PRC) coupling beam, which incorporates a steel bar truss deck as a substitute for the conventional reinforced concrete (RC) slab. In order to study the effect of different types of RC slabs on the performance of PRC coupling beams, the low‐cyclic reversed loading test was carried out on three PRC coupling beams. The differences of failure modes, load bearing capacity, stiffness degradation, and energy dissipation capacity of each coupling beam are analyzed. The finite element software ABAQUS is used to analyze the stress distribution in the concrete, steel plate, and reinforcement skeleton of the novel coupling beam. The results show that the incorporation of a steel bar truss deck in PRC coupling beams with a small span‐to‐depth ratio can effectively enhance their shear bearing capacity and energy dissipation capacity. The inclusion of a slab significantly enhances the load‐bearing capacity of the coupling beam, while the utilization of a steel bar truss deck in PRC coupling beams greatly improves their overall bearing capacity. The PRC coupling beams featuring a steel bar truss deck exhibit superior load capacity compared to those with conventional RC slabs. The cumulative energy dissipation at the damage point in PRC beams with a steel bar truss deck is 1.39 times greater than that of the coupling beam without slabs and 1.18 times higher than that of the coupling beam with traditional RC slabs.

Research on Optimization Design of Prefabricated ECC/RC Composite Coupled Shear Walls Based on Seismic Energy Dissipation

This study explores an advanced prefabricated composite structure, namely ECC/RC composite shear walls with enhanced seismic performance. This performance enhancement is attributed to the strategic use of engineered cementitious composites (ECC) known for their superior ductility. The study conducts both experimental and numerical simulation analyses to scrutinize the seismic energy absorption capabilities of this innovative structure. Emphasis is placed on critical aspects, such as the optimal deployment areas for ECC within composite coupling beams and shear walls, the grade of ECC strength, the proportion of stirrups in coupling beams, and the caliber of longitudinal reinforcement. Through finite element analysis, this research quantitatively assesses the impact of these variables on seismic energy dissipation, incorporating evaluations of load–displacement hysteretic behaviors and the energy dissipation potential of ECC/RC shear wall samples. The findings suggest the optimal ECC application in the coupling beams, and within a 14% structural height at the base of shear walls. Recommended design parameters include an ECC strength grade of E40 (40 MPa), longitudinal reinforcement of HRB400 (400 MPa), and a stirrup ratio in coupling beams of 0.5%.

Seismic Design and Performance of Composite Coupling Beam-to-SpeedCore Wall Connections

Coupled composite plate shear walls—concrete filled (CC-PSW/CFs) are an effective seismic lateral-force-resisting system for the design and construction of mid- to high-rise buildings around the world. The coupled system consists of two or more composite plate shear walls—concrete filled (C-PSW/CFs) connected to each other using composite coupling beams located at the story heights. The CC-PSW/CF system can provide higher overturning moment capacity, lateral stiffness, and ductility than uncoupled walls. Concrete-filled steel box sections are typically used for the composite coupling beams, which are designed to be flexure critical members. When the CC-PSW/CF system is subjected to lateral seismic forces, plastic hinge formation and inelastic deformations (energy dissipation) occur near the ends of most of coupling beams along the structure’s height, followed by flexural hinging of the C-PSW/CFs, typically at the base. This paper presents the details and design of four composite coupling beam-to-C-PSW/CF connection configurations. Six connection specimens representing the four connection configurations, with beam clear span-to-section depth, Lb/d, ratios of 3.5 and 5.1, were designed and tested. The lateral force-displacement and moment-rotation responses of the specimens are summarized. All six composite coupling beam-to-C-PSW/CF wall connection specimens (1) developed and exceeded the plastic flexural capacities, Mp, of the coupling beams calculated using the plastic stress distribution method and (2) developed chord rotation capacities greater than 0.03 radian before their flexural strength degraded to 80% of the plastic moment capacity, Mp.

Seismic behaviour of plate-reinforced composite coupling beams with RC slabs

In practical engineering, reinforced concrete slabs are generally poured together with coupling beams. Therefore, the influence of reinforced concrete (RC) slabs on the stress of coupling beams cannot be ignored. To study the influence of RC slabs on the mechanical properties and failure mechanism of steel-concrete composite coupling beams under earthquakes, four plate-reinforced composite (PRC) coupling beams with RC slabs and one PRC coupling beam without a slab were tested under low cyclic loading. The influence of slab forms on the seismic performance of coupling beams was studied, and the failure process, failure mode, and bearing capacity were analyzed. By establishing a finite element model, the internal force distribution law of the RC slab-PRC coupling beam, and the bending moment distribution law of concrete, steel bars, and steel plates were analyzed. The results show that the setting of steel plates and RC slabs can significantly improve the shear and energy dissipation capacity of coupling beams. The compression wave buckling deformation of the steel plate mainly occurs at the beam-wall joints. The setting of semi-through cracks in the reinforced concrete slab can delay the crack displacement of the coupling beam and reduce the damage to the slab at the initial stage of loading.

Seismic performance and numerical analysis of steel plate-fiber reinforced concrete composite coupling beams

To improve the seismic performance of reinforced concrete coupling beams with small span-to-height ratio, a steel plate-fiber reinforced concrete coupling beam is proposed in this paper. Quasi-static tests of a steel plate-fiber reinforced concrete composite coupling beam and a steel plate-reinforced concrete composite coupling beam have been completed. Seismic performance metrics such as failure process and bearing capacity were analyzed. Finite element software was used to analyze the stress development of concrete, steel plates, and steel rods coupled to beams under three operating conditions, as well as the distribution laws of axial forces, shear forces, and bending moments of the embedded plates. The results show that steel plate - fiber reinforced concrete coupling beam has high bearing capacity, energy dissipation capacity and ductility. The addition of fibers effectively controls the expansion of the initial cracks in the concrete and works better with steel plates. The maximum stress of the embedded steel plate is at the junction of the beam walls. The axial force of the coupling beam steel plate is U-shaped, which is subjected to a large axial force at the end and the minimum axial force in the middle, but the shear force at the end of the coupling beam steel plate is the smallest, and the closer to the middle, the greater the shear force.

Evaluation of seismic response of coupled wall structure with self-centering and viscous damping composite coupling beams

In order to reduce the residual displacement and floor acceleration of coupled wall structures, a novel self-centering and viscous damping composite coupling beam is proposed. The proposed coupling beam consists of the elastic beam segments and the fuse part, which incorporates self-centering friction dampers and viscous dampers. The self-centering friction damper can provide strength and stiffness for the proposed coupling beam and reduce the residual displacement of the coupled wall structure. The viscous damper can add supplemental damping to the system, and this can control the peak lateral displacement demands and floor accelerations of the structure. Moreover, the proposed coupling beam can eliminate the beam elongation effect of the self-centering coupling beam with a rocking behavior. Design methodology and nonlinear numerical model of the proposed coupling beam are developed. The seismic behaviors of the coupled wall structure with the self-centering and viscous damping composite coupling beams (CW-SCVCCB) are assessed and compared with the structure with reinforced concrete coupling beams (CW-RCCB), the structure with steel coupling beams (CW-SCB) and the structure with self-centering coupling beams (CW-SCCB). Analysis results showed that the supplemental viscous damping can effectively reduce the peak interstory drift ratio and floor accelerations of the structure. The residual displacement of the novel coupled wall system is larger than that of the CW-SCCB, however, it is significantly reduced compared with the CW-SCB and the CW-RCCB.

Behavior of Prefabricated Composite Arch Coupling Beam for Shear Walls Subjected to Cyclic Loading

Under seismic loading, the coupling beam not only connects the wall stems together, but also plays a role in energy dissipation and shock absorption. On the basis of a literature review, this paper presents a new type of prefabricated concrete arch coupling beam with steel connectors. The structure of the prefabricated beam and its connection with the wall stems are introduced. The seismic performance of the beam-wall joint is analyzed through experimental research and finite element analysis. The results show that the arch beam effectively improves the shear bearing capacity of the beam-wall connection, thus improves the overall seismic performance of the coupled wall structures. This research provides a useful reference for developing design codes for prefabricated coupling beams.

Seismic behavior of coupled wall structure with steel and viscous damping composite coupling beams

In order to reduce the interstory drift ratio and floor acceleration of coupled wall structure, a new type of steel and viscous damping composite coupling beam (SVDCCB) is developed. The proposed SVDCCB consists of a central fuse element and two steel beam segments on both side of the beam. The fuse element is composed of chord members, buckling-restrained energy dissipaters and viscous dampers. The energy dissipaters are used to dissipate seismic energy and the viscous dampers are used to add supplemental damping to the structure. Moreover, the dampers are placed at the corners of the fuse element to reduce the weight of the damper, in this way, the damaged energy dissipaters and viscous dampers can be quickly replaced after earthquake. A nonlinear numerical model and design methodology of the coupling beam are developed. A shear wall prototype building was modeled in OpenSees and the seismic performance of this structure was investigated under different intensities of earthquake excitations. The seismic behaviors of the coupled wall structure with the novel coupling beams (CW-SVDCCB) are evaluated and compared with the structure with concrete reinforced coupling beams (CW-RCCB) and the structure with steel coupling beams (CW-SCB). Results indicated that the weight of single energy dissipater arranged at the corner of the fuse can be greatly reduced compared with in the diagonal direction of the fuse. The SVDCCB can efficiently limit the floor accelerations of the structure compared with the other two types of coupling beams. Moreover, the residual fuse rotation of SVDCCB is smaller than that of the steel coupling beam means that the SVDCCB can be replaced more conveniently.

Capacity Design of Coupled Composite Plate Shear Wall–Concrete-Filled System

Composite plate shear walls–concrete-filled (C-PSW/CF) are a new and innovative lateral force–resisting system intended for high-rise buildings. High-rise building applications of this system are particularly efficient in the coupled wall configuration, in which the walls are C-PSW/CF and the coupling beams are concrete filled steel box sections. This paper presents a capacity design principle for the seismic design of coupled composite plate shear wall–concrete filled (CC-PSW/CF) systems. The capacity design principle implements a strong wall–weak coupling beam approach, in which flexural yielding occurs in the coupling beams before flexural yielding at the base of walls. The coupling beams are sized to resist the calculated seismic lateral force level. The composite walls are sized to resist an amplified seismic lateral force corresponding to the overall plastic mechanism for the structure, while accounting for the capacity-limited forces from the coupling beams and the coupling action between the walls. The paper summarizes the recommendations and requirements for appropriate sizing of the composite coupling beams and walls. These recommendations were used along with the capacity design principle to design four example (8–22-story) structures and evaluate their seismic behavior. The structures were modeled using benchmarked finite-element models and fiber-based models that accounted for the various limit states, including steel yielding, local buckling, fracture, concrete crushing, confinement, and tension cracking. The numerical models were analyzed for monotonic pushover loading and scaled seismic ground motions. The structural responses from the nonlinear pushover analysis and the nonlinear time history analyses were in accordance with the capacity limited design philosophy, thus confirming its efficacy.

Simplified shear force-chord rotation relationship for concrete-filled steel plate composite coupling beams

Concrete-filled steel plate (CFSP) composite coupling beam is a new type of coupling beam with large deformation and energy dissipation capacity. Given the need for shear force-chord rotation envelope curve of the coupling beam in the general modeling and analysis of coupled CFSP composite shear wall structures, this paper presents an envelope curve for CFSP composite coupling beams based on the results of nonlinear finite element analysis. A comparison between the results of finite element analysis (FEA) and the existing experimental data demonstrates the ability of the numerical model to accurately predict the shear force-chord rotation hysteresis curve and the local response of CFSP composite coupling beams. To gather sufficient data for plotting the envelope curve, multiple numerical models with different values assigned to the span/depth ratio, web plate thickness, flange plate thickness, and compressive strength of the concrete are analyzed under cyclic lateral loading. The analysis results are used to derive some equations for calculating the effective flexural and shear stiffness of the coupling beam based on the stiffness of steel plates and concrete infill, with a reduction coefficient applied to the stiffness contribution of the concrete. Some suggestions are provided for calculating the maximum and yield strengths of the coupling beam, based on the minimum strength corresponding to shear failure and flexural capacity. Finally, the analysis results are used to provide a trilinear model for the shear force-chord rotation hysteresis envelope of CFSP composite coupling beams.

Mechanical performance analysis of U-shaped steel-concrete composite deep coupling beam

In this paper, semi-span simply supported beam is used to simulate the mechanical behavior and failure mode of U-steel reinforced concrete composite-deep coupling beam, and three U-steel reinforced concrete composite beams, with same height-span ratio of 1/3, were tested under one-point vertical concentrated loading in mid-span. Theresults show that the mid-span yield height exceeds 60% of U-steel-concrete composite beams flange, and that the three of U-steel-concrete composite beam specimens aredamaged, there is a critical oblique crack in the inner concrete of the beam that is roughly parallel to the line between the bearing center and the loading point. It is concluded that the failure mode of this type of U-shaped steel-concrete beam begins with yieldat mid-span bottom and flanges of U-shaped steel, and ends with concrete shear failure.

Seismic Performance of LRS-FRP–Concrete–Steel Tubular Double Coupling Beam

To improve the ductility and seismic performance of a double coupling beam, the authors applied a polyethylene terephthalate (PET) sheet and steel tube to form fiber-reinforced polymer (FRP)–concrete–steel double-skin tubular (DST) composite coupling beams. A low-cyclic reversed experimental program was carried out which factored in the member form, steel tube diameter, and construction methods. The results indicate that the ductility and energy dissipation performance of double coupling beams—whether wrapped with a PET-FRP sheet or surrounded by an FRP–concrete–steel DST composite system—is a substantial improvement over the traditional reinforced-concrete double coupling beam (RC-DCB). The ductility coefficient and accumulated energy dissipation of the DST-DCB members improved above 170% and 2300%, respectively. These percentages compare to the RC-DCB and are based on the rupture of a PET-FRP sheet. The results are similar to those of the large rupture strain double coupling beam (LRS-DCB). Meanwhile, the external wrapped PET-FRP sheet does not affect the initial stiffness and peak strength of the RC-DCB. Relatively, the inner steel tube will improve the initial stiffness, yielding strength, and peak strength. DST-DCB members still have considerable deformability after 85% of peak strength since the external PET-FRP sheet provided an effective constraint effect on the core concrete and the inner steel tube could bear excellent shear deformation.

Stiffness Reduction Coefficient of Steel Plate-Reinforced Concrete Composite Coupling Beams

Stiffness Reduction Coefficient of Steel Plate-Reinforced Concrete Composite Coupling Beams

Seismic performance of subassemblies with composite wall and replaceable steel coupling beam

ABSTRACTHybrid coupled wall (HCW) systems, especially with properly designed steel coupling beams, are efficient lateral load resisting systems. To further improve the seismic resiliency of HCW structures after major earthquakes, a new hybrid system consisting of steel plate composite structural wall piers and steel coupling beams with a replaceable fuse was developed. This paper presents an experimental program of three half-scaled subassemblies subjected to pseudo-static cyclic loading. Each test specimen consisted of two segments of composite wall piers and a steel coupling beam with and without a replaceable fuse. The details of the wall piers were identical for the three subassemblies, but three different coupling beams with the same span/depth ratio were used. One subassembly using a steel coupling beam without a replaceable fuse served as the control specimen, which was loaded up to 10% chord rotation following a preselected loading protocol. The other two specimens employed the new hybrid system. The fuse in these two subassemblies was replaced in situ after subjecting the coupling beam to 2% chord rotation, and the specimen was subsequently loaded up to 10% chord rotation. A detailed evaluation of the test results indicates that the new hybrid system can exhibit excellent performance and the replaceable fuse (and its connection details) proved to be a reliable technique to restore the performance after subjecting the coupling beam to chord rotations that are expected during design-level earthquakes. The load transfer mechanism and seismic performance varied depending on the details of the replaceable details of steel coupling beams.

A Ladder At Its Core

The ladder-core system is a novel structural system for supertall towers that was created by SOM for Tower 1 at Shum Yip Upperhills, a mixed-use development in Shenzhen, China. The system features eight megacolumns at the perimeter that form the vertical rails of the ladders on the four corners of the core. Composite coupling beams—the ladder rungs—connect the megacolumns to the interior core, creating a comprehensive lateral system that allows for unobstructed occupant views, simplicity of the floor plates, and inherent structural stability.

Shear strength prediction of PRC coupling beams with low span-to-depth ratio

The seismic performance of a coupled shear wall system is governed by the shear resistances of its coupling beams. The plate-reinforced composite (PRC) coupling beam is a newly developed form of coupling beam that exhibits high deformation and energy dissipation capacities. In this study, the shear capacity of plate-reinforced composite coupling beams was investigated. The shear strengths of PRC coupling beams with low span-to-depth ratios were calculated using a softened strut-and-tie model. In addition, a shear mechanical model and calculating method were established in combination with a multistrip model. Furthermore, a simplified formula was proposed to calculate the shear strengths of PRC coupling beams with low span-to-depth ratios. An analytical model was proposed based on the force mechanism of the composite coupling beam and was proven to exhibit adequate accuracy when compared with the available test results. The comparative results indicated that the new shear model exhibited more reasonable assessment accuracy and higher reliability. This method included a definite mechanical model and reasonably reflected the failure mechanisms of PRC coupling beams with low span-to-depth ratios not exceeding 2.5.

Experimental and numerical study of PRC coupling beams with low span-to-depth ratio

Plate-reinforced composite (PRC) coupling beams are manufactured by embedding a vertical steel plate into conventionally reinforced concrete coupling beams to enhance their strength and ductility. This study presents a series of quasi-static tests conducted to examine the seismic behavior of PRC coupling beams and provide a scientific basis for the analysis of the shear bearing capacity of PRC coupling beams. The experimental results of seven PRC coupling beam specimens with low span-to-depth ratio tested under reversed cyclic loading are discussed. Particle image velocimetry technology is used to accurately measure the deformation performance of PRC coupling beams. The influence of span-to-depth ratio, sectional steel plate ratio, and the slab on the seismic behaviors of specimens were investigated. The experimental results indicate that, compared with PRC coupling beams without slab, PRC coupling beams with slab can increase horizontal cracking displacement and significantly improve the shear capacity and energy dissipation capacity of PRC coupling beams without slab. Embedded steel plates can improve the limited values of the shear compression ratio of coupling beams. Nonlinear finite element analysis was also carried out to model the PRC coupling beams. The numerical results indicate that the tension-softening property of concrete was more accurately simulated by the stress-crack width relationship of concrete. The internal force distribution of concrete stress, steel plate shear force, bending moment, and axial force of PRC coupling beams with low span-to-depth ratios were further analyzed. This study will benefit engineers designing PRC coupling beams.

EXPERIMENTAL RESEARCH ON ASEISMIC BEHAVIOR OF HIGH DUCTILE CONCRETE FILLED STEEL PLATE COMPOSITE COUPLING BEAMS

To improve the aseismic behavior of coupling beams with a small span-to-depth ratio, high ductile concrete (HDC) is used to replace the concrete. Two HDC filled steel plate composite coupling beams, one concrete filled steel plate composite coupling beam and one HDC steel plate composite coupling beam, were designed. The failure pattern, deformation capacity and energy dissipation capacity of composite coupling beams were studied by the quasi-static tests. The experimental results show that the deformability and damage-tolerance of the steel plate composite coupling beams can be improved by replacing concrete with HDC. The synergistic performance of HDC and steel webs is good, which is beneficial to the shear effect of steel webs. The energy dissipation of the HDC filled steel plate composite coupling beams is significantly higher than those of the concrete filled steel plate composite coupling beam and of the HDC steel plate composite coupling beam. The design values of shear-compression ratio of the HDC filled steel plate composite coupling beams is 0.65-0.70, which is obviously higher than that of the HDC steel plate composite coupling beam. Therefore, the shear-compression ratio limitation of the coupling beams can be improved by using the HDC filled steel plate composite coupling beams, and the problem of shear-pressure ratio ultra-limit of coupling beam in design can be solved.

Study on Performance Index Quantification of PRC Coupling Beam-Hybrid Coupled Shear Wall System

PRC coupling beam-hybrid coupled shear wall system is a new structural system with plate-reinforced composite (PRC) coupling beam instead of concrete coupling beam in the traditional reinforced concrete coupled shear walls. There is a lack of systematic research on PRC coupling beam-hybrid coupled shear wall system at home and abroad. In this paper, the seismic performance levels of PRC coupling beams and shear walls were partitioned. Combined with the characteristics of PRC coupling beam-hybrid coupled shear wall system, the failure features at different performance levels are put forward. Meanwhile, story drift angle limitation for PRC coupling beam-hybrid coupled shear wall system under different performance levels is obtained. According to the using function and importance of PRC coupling beam-hybrid coupled shear wall system, the seismic performance target of which is given combined with different earthquake action levels.

Experimental study on demountable steel-concrete connectors subjected to combined shear and tension

Composite beams are being used increasingly in construction due to their benefits over beams consisting of the steel component alone. In some applications such as in composite coupling beams and infill walls, steel-concrete connectors must resist uplift forces in addition to shear forces. Therefore, there is a need to carry out experimental testing to investigate the performance of steel-concrete connectors under combined loading. Furthermore, the separation of the steel and concrete components is a destructive activity and requires remelting of the steel component if it is to be reused. Remelting requires energy that usually comes from unsustainable resources. Hence, research has been carried out in this paper on demountable steel-concrete connectors as they allow demounting and easy separation of the steel and concrete components and reuse.The performance of three types of steel-concrete connectors subjected to combined shear and tensile loading was investigated experimentally. A pull-out test was carried out to determine the tensile resistance of each type of steel-concrete connector. This was followed by a series of modified push tests to determine the interaction between shear and tension loading. Tensile resistance which had been determined from pull-out tests was applied in increments of 25% to each group followed by shear loading until failure of the steel-concrete connector was observed.Based on the experimental investigation carried out, significant reduction in shear resistance was observed when tension was applied. The results are also compared with existing relationships for headed studs under combined shear and tensile loading to determine which relationship is most reliable in predicting the shear-tension resistance interaction of demountable steel-concrete connectors.