Steel Coupling Beams Research Articles

Hybrid simulation of steel frames with Dissipative Replaceable Link Frame and high-strength steel coupling beams

The paper describes the results of an experimental campaign conducted on full-scale steel frames equipped with dissipative components within the European Research Fund for Coal and Steel (RFCS) pilot project DISSIPABLE. Dissipative Replaceable Link Frame (DRLF), whose characteristic is the large energy dissipation combined with ease of replacement, were installed on the frame and coupled through high-strength steel (HSS) beams characterised by an elastic response to increase the overall frame stiffness and to improve the re-centring capability after a major seismic event. The seismic performance of the steel frame was investigated by means of Hybrid Simulation (HS) at three different limit states, i.e., damage limitation (DL), significant damage (SD) and near collapse (NC). In particular, the first floor of the frame was physically built, whilst the response of the remaining five floors was numerically simulated. The results of the tests highlighted the large dissipation capabilities of the DRLF system. In addition, the high-strength steel coupling beams remained elastic even at the NC limit state and provided excellent behaviour in increasing stiffness and re-centring capabilities. Finally, the repairability of the DRLF components was demonstrated.

Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams

Seismic performance evaluation of hybrid coupled shear wall system with shear and flexural fuse-type steel coupling beams

Sustainable Seismic Performance of Diagrid Core-Tube Structure with Replaceable Steel Coupling Beam

The diagrid core-tube structure has been widely used in high-rise buildings in recent years, but there are few studies on the sustainable energy dissipation measures and seismic performance improvement of such structural systems. Because the coupling beam is the element connecting the inner tube and the outer tube in the diagrid structure, it is the first seismic defense line and an important energy-dissipation member in the seismic design of the overall structure. Therefore, this paper replaces the traditional reinforced concrete coupling beam of the inner tube of the shear wall with a replaceable energy-dissipation steel coupling beam, and the strength, stiffness, and stability of the replaceable steel coupling beam are designed to improve the sustainability of the structure. By changing the position of the replaceable coupling beam, the relative stiffness of the inner and outer tubes of the diagrid tube structure, and the plane form of the structure, the static elastoplastic analysis and seismic response energy analysis of different diagrid tube structures are carried out, and the influence of the replaceable coupling beam on the sustainable seismic performance of the diagrid tube structure is studied. The results show that the replaceable coupling beams have little effect on the ultimate bearing capacity of the structure, but the ductility and sustainability of the structure are significantly improved, and the whole building layout is the optimal layout scheme. The setting of replaceable coupling beams makes the diagrid tube structure show hysteretic energy-dissipation earlier under the action of large earthquakes, and the proportion of hysteretic energy-dissipation is greatly improved, which reduces the inter-story drift ratios and the damage degree of the diagrid columns under the action of large earthquakes. When the relative stiffness of the outer tube of the diagrid tube structure is small or the plane form of the structure is a regular quadrilateral, the application of replaceable coupling beams is more effective in improving the ductility and sustainability of the structure and reducing the damage to the diagrid column under large earthquakes.

Seismic behavior and shear capacity prediction of coupled concrete‐filled multicellular steel tube composite shear walls

AbstractIn this paper, a coupled concrete‐filled multicellular steel tube composite shear walls structure (CCSSW) is proposed. A finite element model (FEM) is developed to investigate the seismic behavior of CCSSW, and the model was validated by the tests. The effects of four parameters including axial compression ratio (ACR) on the hysteretic behavior of the CCSSW were studied. Then, a theoretical model for predicting the ultimate shear capacity (USC) of CCSSW was established. The results show that the failure mode of coupled walls exchanged from flexural failure to flexural‐shear failure with increasing the ACR, and it is recommended that the ACR should less than 0.6 to ensure the ductility requirement. To better realize the function of the first line of defense of steel coupling beam (SCB), following recommendations are concluded: the span‐to‐depth ratio range of SCB is 4.0–6.0, the wall stiffness ratio is 2.4–4.7, and low yield strength material should be used for SCB. The maximum error on USC between FEM results and theoretical results is 12.8%, and most of them are less than 10%, indicating the effectiveness of the proposed theoretical model.

Dynamic principle analysis of reinforced concrete replaceable coupling beam energy dissipation structure

Reinforced concrete shear wall is one of the most common structures in tall buildings. As an effective means to control structural vibration response, energy dissipation damping is widely applied to reinforced concrete shear wall structures. Replaceable steel coupling beams (RSCB) is a new technology in the energy dissipation damping field, and are being gradually adopted by construction projects since their introduction. However, current research on RSCB damping performance and space optimization has some shortcomings. This paper discusses RSCB working principles based on structural dynamics theory and derives damping performance curves of corresponding structures, and a primary evaluation of seismic response method for RSCB structures is proposed. Finally, the energy dissipation performance of a typical reinforced concrete shear wall structure is analyzed based on performance curves and formula of structural dynamics constructed by this paper. Relevant outcomes of this paper will provide theoretical support and technical guidance for construction design and in-depth research of RSCB.

Study on the seismic performance of replaceable concrete coupling beams with RC slabs by experiments and simulations

The objective of this paper was to analyze the seismic behavior of replaceable concrete coupling beams (RCCB) with reinforced concrete (RC) slabs and compare them with replaceable steel coupling beams (RSCB). And it focused on the damage of the slab and the influence of slab configurations on the mechanical properties of coupling beam. Five full-scale specimens were fabricated for failure test, among which four were RCCBs and one was RSCB. The test results showed the damage of the slab could be reduced by improving the deformation capacity of the slab or replacing the concrete with ECC materials. By using OpenSees, contributes of the slab to the coupling beam was analysed considering the extrusion of the slab and coupling beam, the influence of elevating distance of slab and pretension force of the prestressed tendons on the seismic performance of coupling beams and slabs were discussed, and the axial mechanical properties of the coupling beams during loading were investigated.

Experimental study on replaceable shear link on reinforced concrete shear wall

Experimental study has been conducted on specimens of a half-scale coupled reinforced concrete shear wall with steel coupling beam and an inserted shear link, to investigate the seismic performance of the core-wall and the replaceability of the shear link as a mechanical damper to dissipate the seismic energy. The link was designed following requirements for typical shear link, while the coupling beams as well as the shear wall were designed based on the link capacity. The result showed that under the prescribed cyclic loading (AISC 341-2016), the sub-assembly performed as expected, as shown by a good hysteretic curve with the plastic strain of shear link exceeded 0.08 radian. The damage was limited on the shear link, while the steel coupling beam and steel bar in the reinforced concrete wall remained elastic. Moreover, the experimental study showed no permanent distortion on the steel coupling beam after series of shear-link replacement. This confirmed the replaceability of the shear links as an excellent seismic device in the core-wall system.

RC wall and steel side columns coupled structural system: Experimental and numerical investigations

The reinforced concrete (RC) wall coupled with steel side columns (SSC) using steel coupling beams were studied both experimentally and numerically. A 1/4 scaled 5-story test model was constructed and tested to failure under reversed lateral cyclic and constant axial loads. Test results proved that the coupling mechanism can be effectively realized in this unique coupled structural system involving only one wall pier. In order to reveal more seismic response characteristics in addition to the test results, numerical parametric studies were conducted based on the validated finite element modeling techniques. Results indicate the medium levels of axial load ratio and span-to-depth ratio of the steel coupling beam, or low level of wall aspect ratio, can lead to acceptable lateral load capacity and displacement ductility of the RC wall and SSC coupled structural system.

Experimental evaluation of post-tensioned hybrid coupled shear wall system with TADAS steel dampers at the beam-wall interface

Considering the optimal seismic resistance of coupled shear walls and the perks of self-centering systems, throughout this research, the hysteretic performance of post-tensioned concrete “Coupled Wall” (CW) subassemblies with “Steel Coupling Beam” (SCB) equipped with “Triangular Added Damping and Stiffness” (TADAS) steel dampers was experimentally evaluated. To dissipate the energy input from the earthquake, metallic yield dampers of the TADAS type were used at the connection zone between the beam and the wall in this structural system. Using a SCB rather than a concrete beam was suggested to reduce beam damage and maintain the system’s self-centering capabilities during lateral loading. High-strength steel strands were employed to generate post-tensioning along the beam’s longitudinal axis in the “Coupled Wall System” (CWS) to reduce structure residual deformation under seismic loading. In the first portion of this research, an experimental assessment of the load–displacement behavior of TADAS dampers exposed to cyclic loads was performed. Then, at floor level, three ⅔-scaled CW subassemblies were constructed using a post-tensioned SCB and subjected to lateral quasi-static cyclic loading of increasing amplitude. Various post-tensioning stresses were applied to one subassembly lacking energy dissipation devices and two subassemblies with TADAS dampers. The findings demonstrate that TADAS-equipped subassemblies can endure major non-linear deformations up to 8% drift without struggling either residual deformation or severe injury. Installing TADAS dampers at the beam-wall interface heightened the specimens’ capacity to withstand lateral loads by 71% to 90% and considerably increased their potential to dissipate energy.

Performance of steel coupling beam with trapezoidal corrugated web: experimental tests and numerical analysis

Performance of steel coupling beam with trapezoidal corrugated web: experimental tests and numerical analysis

Behavior of double skin composite core wall subject to biaxial cyclic loads

This study performed a biaxial cyclic test on scaled double skin composite (DSC) core wall. The core wall consisted of two C-shaped DSC shear walls and steel coupling beams (SCBs) connecting the walls. In particular, seismic behavior of the core wall subject to reversed biaxial cyclic load was investigated. The failure mode of the core wall mainly included its local buckling of steel faceplate, fracture of vertical butt welds, fracture of side plate, and concrete crushing at the corners of walls. The lateral shear resistance in its two directions was mutually coupled. Once loaded in one direction, lateral shear resistance in other direction compromised. Due to energy dissipation of SCBs in their Y-direction, hysteresis loop for Y-directional loading was fuller than that for X-directional loading, and equivalent damping ratio of X-direction was 31.91% greater than that of Y-direction at ultimate point. Their initial stiffness in X-direction without SCBs configuration was the highest, and ductility coefficient of X- and Y-directions was relatively close, within 4.63–5.47%. The strain distribution curves along DSC shear wall bottoms of core wall before its peak resistance showed plane section assumption was valid under biaxial lateral load. In particular, DSC core wall high-rise buildings were promoted in this study.

Seismic behavior of steel plate and reinforced concrete composite wall coupled to steel side columns

The steel plate and reinforced concrete (SPRC) composite wall coupled to steel side columns is a new type of coupled system, which consists of a single SPRC composite wall coupled to steel side columns through steel coupling beams at all floors. One 1/4 scaled five-story SPRC composite wall coupled to steel side columns with a plastic coupling ratio (CR) of 0.45 was designed, constructed, and tested under simulated earthquake action. The test results exhibited great seismic performance of the proposed coupled system with the coupling mechanism fully developed. The average displacement ductility coefficient was 3.12. And the average values of the inter-story drift ratio of all stories at the yield, peak load, and ultimate conditions were 1.32%, 2.55%, and 3.70%, respectively, showing good inter-story deformation capacity. The average ultimate plastic shear rotations of steel coupling beams at the 2nd, 3rd, 4th, and 5th floors were 0.0211 rad, 0.0364 rad, 0.0556 rad, and 0.0913 rad, respectively, indicating great energy dissipation contributions of the steel coupling beams. The steel side columns remained elastic under shear forces transmitted from steel coupling beams through hinge joints and provided a stable overturning moment resistance to protect the SPRC wall. The accuracy of the test results was verified against the numerical analysis results. The parametric analyses were conducted to further the understanding on the influences of key design parameters on the seismic performance of the proposed coupled system. The peak lateral load can be enhanced by increasing the axial load or steel plate ratio. In order to obtain good energy dissipation capacity and ductility, a moderate value of 0.15 for the axial load ratio or 6.6% for the steel plate ratio can lead to excellent deformation capacity.

Seismic performance of self-centering hybrid coupled wall systems: Preliminary assessments

Hybrid Coupled Wall (HCW) systems consist of reinforced concrete walls connected with steel coupling beams. HCWs benefit from the superior lateral stiffness of the reinforced concrete walls, while the coupling mechanism reduces the moment demand at the base of the walls. The present study investigates the seismic performance of a new HCW system equipped with friction-damped self-centering coupling beams and examines the efficiency of the new system in reducing residual deformations. The coupling beams of the intended HCW system consist of self-centering links, which can be easily repaired after severe earthquake events. The self-centering system utilized in this study features the following advantages distinguish it from conventional self-centering solutions: (i) it eliminates the coupling beams elongation problem (ii) it facilitates the application of pre-fabricated self-centering components to mitigate uncertainties raised by post-tensioning the connections on site. In this paper, the seismic behavior of the proposed lateral load-bearing system is investigated under several ground motion records and intensities. It is demonstrated that the applied self-centering mechanism has the capacity to minimize earthquake-induced residual deformations and repair time without increasing the damage level expected for the concrete walls in conventional HCWs.

Study of replaceable and static properties of assembled steel coupling beams with different connection modes

To improve the seismic energy dissipation capacity and quick recovery capacity of buildings, the use of replaceable components is a key research area in the field of earthquake engineering, of which the design and performance of replaceable coupling beams are one of the focuses of the research. To study the influence of connection modes on the replaceability and mechanical properties of a replaceable steel coupling beam after an earthquake, three types of connection modes for an I-section energy-dissipating beam have been designed in this study. They are the lug plate-bolt group connection (CB1), end plate-bolt group connection (CB2), and end plate-bolt-shear key connection (CB3). Full-scale model replacement tests of replaceable steel coupling beams with the three types of connections were carried out. Furthermore, a real-time 3-dimensional attitude model was developed to assess the replaceability of a coupling beam after an earthquake. In addition, full-scale model static load tests and finite element simulations of the coupling beams were carried out. The mechanical characteristics, such as the bearing capacity, stiffness, and failure mode under monotonic static loading, have been analyzed. The results of the replacement test show the following. The maximum replaceable residual shear angles of the energy-dissipating beams with CB1, CB2, and CB3 are 0.008 rad, 0.007 rad, and 0.01 rad, respectively. Of the three types of connections, the operation of replacing CB3 is the easiest. The results of the static load test and the finite element simulation show the following. The connection modes of the energy-dissipating beams and the nonenergy-dissipating beams have a great influence on the stiffness of the coupling beams and some influence on the deformation capacity of the coupling beams. However, the types of connections have no obvious influence on the bearing capacity of the coupling beams. According to the comprehensive comparison, the plastic deformation of CB3 is more concentrated on the web of the energy-dissipating beam, and the safety reserve of the connecting joint is higher, which shows that the design of CB3 is better than those of CB1 and CB2.

Experimental Study on Seismic Behavior of Coupled Steel Plate and Reinforced Concrete Composite Wall

The coupled steel plate and reinforced concrete (C-SPRC) composite wall is a new type of coupled-wall system consisting of steel coupling beams (SCBs) that join two SPRC walls where the steel plate shear wall (SPSW) is embedded in the RC wall. Although the C-SPRC wall has been extensively constructed in high-rise buildings in seismic regions, research on its behavior has rarely been reported. No code provisions are available for directly guiding the preliminary design of such coupled-wall systems. In the research, three 1/3-scaled C-SPRC wall subassemblies including one-and-a-half stories of SPRC walls and a half-span of SCB were tested under simulated earthquake action, considering the fabrication method of the embedded SPSW and the shear-span ratio of the SPRC walls as two test variables. The prime concern of the research was to evaluate the influences of those popular design and construction parameters on the seismic behavior of the C-SPRC wall. Deviating from the beam tip loading method used in conventional subassembly tests, the lateral cyclic load in this research was applied at the top of the wall pier so that the behaviors of both walls and SCBs could be examined. The test results exhibited the great seismic performance of the subassemblies with the coupling mechanism fully developed. The energy dissipation capacity and inter-story deformation capacity of the subassembly with the assembled SPSW were roughly 9.4% and 13.2% greater than those with the conventional welded SPSW. Compared with the subassembly with the shear-span ratio of 2.2, the interstory-deformation capacity of the one with the shear-span ratio of 2.0 was increased by approximately 13.4%, while the energy dissipation capacity was decreased by 10.9%. The test results were further compared with the simulation results using the proven-reliable finite element analysis with respect to the hysteretic curves, skeleton curves, energy dissipation capacities and failure patterns.

Cyclic Testing of Replaceable Steel Coupling Beams with Reduced Beam Sections and Moment End-Plate Connections

Cyclic Testing of Replaceable Steel Coupling Beams with Reduced Beam Sections and Moment End-Plate Connections

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.

Seismic Performance of a Hybrid Coupled Wall System Using different Coupling Beam Arrangements

This study implemented multirecord nonlinear dynamic and fragility analysis in order to gain more insight into the hybrid coupled wall (HCW) system. Two potentials are used to construct coupling beams, which are the typical steel coupling beam and the replaceable steel coupling beam. Furthermore, an innovative idea for replaceable beams is discussed utilizing reinforced concrete infill instead of steel stiffeners. A new simplified FE model for such beam is carried out in order to explore how this new beam influences the seismic performance of HCW system. An additional equivalent bare RC wall case study is also taken into account for a comprehensive comparison. A precise 2D modelling method using Opensees platform is adopted after validation against experimental and complex 3D numerical simulations. The results indicate a good effect of the replaceable coupling beams concept upon reducing the vulnerability of wall piers under low and moderate events. In terms of coupling beams fragility, the replaceable steel coupling beams also demonstrate better damage resistance when compared with typical steel beams under low and moderate seismic events. Using reinforced concrete infill instead of steel stiffeners can significantly protect beams maintenance without affecting wall piers’ vulnerability.

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.

Seismic behavior of hybrid coupled shear wall with replaceable U-shape steel coupling beam using terrestrial laser scanning

The hybrid coupled shear wall (HCW) with replaceable coupling beam (CB) is an optimal component to recover buildings promptly after a severe earthquake. However, the reinstallation may be difficult or impossible with an identical CB because of the inelastic relative dislocation between two wall piers. This study proposes a novel HCW with different reinforcement ratios in the connection, which was tested under cyclic loading. After the test, the bolt holes can be located through terrestrial scanning, which is then utilized to fabricate a new CB that can accommodate the deformation between two wall piers. The newly replaced HCW system was also tested. As a result, all virgin test specimens fail in web fracture and show a significant inelastic chord rotation of 0.2 rad, exhibiting an excellent energy dissipation capacity. Meanwhile, the new method to locate the bolt holes after the test is feasible. The replaced HCW fails in the pull-off of anchor bars and shows poor seismic behavior due to the unpatched concrete cover in the connection. To improve the energy dissipation for the replaced HCW, high-strength grouting in the connection can be used and high-strength material can be used to replace the usual anchor bolts.