Plate Connections Research Articles

Comparative investigation on beam-to-beam connection with different types of connecting plates

The spliced glued laminated timber (glulam) beams have extensive applications in large-span timber structures since the length of the long solid wood beams is limited by transportation and construction. This paper investigated the flexural performance of glulam beam-to-beam connections with connecting plates and self-trapping screws. The influence of connecting plate types (steel plate, bamboo scrimber, and plybamboo plate) on the flexural performance of the spliced beams was studied. A total of 12 beams were designed, including the intact beam group (3 specimens) and the spliced beam group (9 specimens). The failure modes, ultimate bearing capacity, stiffness, moment-rotation curves, and carbon emissions of spliced beams with different connecting plates were studied. The test results showed that the failure mode of the spliced beams mainly included bending failure of glulam and fracture of the connecting plates. The average bearing capacity of the spliced beams with bamboo scrimber plates and those with steel plates could reach the intact beams. The average stiffness of the spliced beams with bamboo scrimber plates was higher than that of the splice beams with steel plates, reaching 97.6% of the intact beams. The average bearing capacity and stiffness of the splice beams with plybamboo plate reached 80.9% and 92.7% of the intact beams, respectively. A theoretical model of the spliced beams with bamboo scrimber plates was proposed and verified by tests data. Comparisons of the analytical and the test results reveal that the model can predict the moment capacity of the spliced beams with bamboo scrimber plates corresponding specific failure mode in this test.

Fatigue behaviour of root crack in stiffener-to-deck plate weld at crossbeam of orthotropic bridge decks

Steel Orthotropic Bridge Decks (OBDs) are widely used in long-span and movable bridges. Fatigue resistance analysis plays an important role in the design or assessment of OBDs. One possible fatigue failure is the crack initiating from the weld root of stiffener-to-deck plate connections at crossbeams. A full-scale experimental investigation in this study using a 20 mm thick deck plate with a dimension of 9.4 m × 5.1 m, including three crossbeams, represents the modern designed OBDs. The experiments show an arrest of crack propagation with a final crack depth of approximately 75% of the deck plate thickness. On the contrary, through thickness cracks develop in deck plates of 10 or 12 mm. Hot spot stress based fatigue detail categories (DC) using various failure criteria derived from the tests. Analysis with the effective notch stress shows that the DC has low sensitivity to the amount of weld penetration. The results of analyses with the eXtended Finite Element Method (XFEM), employed to analyse the fatigue crack propagation path and crack arrest, are in line with the experimental study.

Working mechanism evaluations of full-scale joints with bolted-cover plate connection for modular steel buildings

The force-reliability of the modular structural joints is crucial for ensuring the structural integrity of modular steel buildings. However, the welds connecting the beam and column within the module are susceptible to tear during seismic events. This mode of failure greatly undermines the ability of these joints to withstand seismic forces. Four full-scale modular structural joints with bolted-cover plate connection were designed and conducted for seismic performance testing, emphasizing the significance of methods such as reinforcing diagonal braces and strengthening flanges on the protective effect of beam–column welds in the module. The simplified modular structural joint and frame finite element model were proposed based on experimental data, refined finite element modeling, and theoretical analysis. The findings suggest that the seismic behavior of the modular structural joint remains unaffected by variations in axial compression ratio within the designed range of parameters. The beam–column weld of the module in the reinforced joint exhibits almost no weld tearing, and both strengthening methods demonstrate exceptional capacity for energy dissipation. The proposed simplified modeling method facilitates the efficient determination of the modular structural joint bearing capacity and the lateral stiffness of the modular frame. The research findings presented in this paper can serve as a valuable reference point for the engineering design of modular steel structures.

Experimental and FE analysis of the behavior of steel column base connections under tension and bending moment

Most design procedures represent the steel base connection by assuming either a perfectly hinged or a fully rigid connection. However, these kinds of connections are, in fact, semi-rigid or flexible and their actual behavior is complicated. Most of the previous studies investigated these base connections experimentally under moments and axial compression only, which is completely different in the case of axial tension and moment. Therefore, experimental and numerical investigations with variable base plate thicknesses and diameters and arrangements of the anchor bolts were carried out to verify the behavior of this kind of base connection under axial tension and moment. Full-scale steel columns with hinged base plate connections were tested under the effect of two simultaneous actions, axial tension force and bending moment. Moreover, Finite Element (FE) models were developed and verified against the experimental results to conduct a parametric study. The investigated parameters were the base plate thickness and anchor bolt diameter and arrangement. The base plate connections under the effect of axial tension with moment instead of axial compression caused reductions in the rotational stiffness up to 99%. In addition, using only two bolts in this type of connection concentrated stresses on the base plate that led to big deformations. The small base plate thickness deformed easily under the effect of tension force which induced big initial gaps between the steel base plate and the Base beam and subsequently decreased the moment resistance and rotational stiffness of the base plate connection. The big elongation of the anchor bolts with small diameters increased the gap between the steel plate and the Base beam.

EXPERIMENTAL STUDY ON THE STRUCTURAL BEHAVIOUR OF RECYCLED PLASTIC ONE STORY HOUSES

Recycling plastic materials may constitute a relief measure to the global plastic problem. Several companies are now producing recycled plastic for use as construction material in single-story houses. One commercially available layout involves assembling Recycled Plastic Lumber units in a running bond pattern, forming panels confined by horizontal and vertical tie elements joined through bolted steel plate connections. As production of houses is industrialized, the architectural layouts are standardized according to specific distribution and dimensions. This paper presents the findings of an experimental program aimed to characterize the seismic behavior and properties of a one-story house model. To facilitate practical application, the model is referred here as Architectural Standard Model (ASM). The objectives of the test campaign were to investigate the structural behavior of the constituting members and assemblies, and the response of structural walls to cyclic static lateral loads. Three natural scale wall specimens were tested in-plane and two out of plane. Results of natural scale cyclic loading tests demonstrated that structural system of the ASM can perform acceptably safely under high seismic loads if it is adequately fixed to the foundation. The results showed that out of plane loading was the critical pattern and behaved like a unidirectional plate that transmitted load to the columns. In plane observed behavior exhibited predominating rocking component, which suggests considering an evaluation of the system's response using dynamic methods.

중국 고대 판축기술의 변천양상

In this paper, we looked at the rammed earth technology used in the earthen ramparts in ancient China. So far, research related to the rammed earth in China has focused on the combination of pangoe(版塊) and individual traces such as woodboards, wooden pillars, horizontal woods, and strings, and there has been a lack of attempts to identify the rammed earth technology of the entire rampart of each remains. I examined the rammed earth pattern of the entire rampart through the examination of the rampart earth structures and rampart methods. As a result, China's ancient rammed earth technology appears when ramparts begin to be built on mid~downstream of the Yellow river in the late neolithic yangshao culture(仰韶文 化). In the literature records, it can be seen that in addition to rampart earth structures (corresponding to types A and C) that fix the wooden plates with wooden pillar called ‘jeong(楨)’and ‘gan(幹)’, Chinese ancient ramparts were built using various rampart earth structures. The rammed earth method also used various methods such as banggoe rammed earth(方塊 版築), bundan rammed earth(分段版築), yeonjeop rammed earth(連接版築), and if you look at the relationship with the rammed earth structure, you can see that each rammed earth method uses one or two types of rammed earth structures to build the rampart. In particular, the appearance of methods for connection of wood plates and supporting and fixing the wood plate by using horizontal wood has led to a change in the rammed earth structure as well as its methods too. In the meantime, archaeological investigations of ramparts in China have been conducted mainly in the midland areas, and the study of construction technology was not very detailed, so it is still difficult to specifically identify the transformation of rammed earth technology in other areas except mid~downstream of the Yellow river. In the future, if archaeological research and research continue to be accumulated and a lot of achievements, we hope that more advanced research will be conducted not only on the transformation of rammed earth technology in each region of China, but also on its relationship with Korea, and I hope that this paper will help us understand Korea's ancient rammed earth technology.

Simulation Analysis of the Structure of an Integrated Modular House by Flat Pack Based on the Elastic–Plastic Contact Theory and Experimental Study of Its Corner Fitting Joint

Based on the elastic–plastic contact theory, elastic–plastic contact finite element models for the integrated modular house by flat pack are established. The structural stress and displacement distributions are obtained. An experimental test is conducted to study the performance of the corner fitting joint of the house. The finite element analysis and experimental test comprehensively demonstrated the safety and reliability of the house structure. The results show that the most unfavorable stress point of the house is located at the corner fitting joint. When the end plate connection holes of the corner column seal are designed with through holes and internal screw holes, respectively, the fastening effect of bolting between the corner fitting and corner column using the internal screw hole is better. The reliability of the repeated disassembly and assembly of the house is verified via multiple loading–unloading simulation cycle experiments of the corner fitting joint. The results of the study provide technical support and a reference basis for the optimal design and ensuring the service performance of the integrated modular house by flat pack.

Seismic performance of rocking braced frames with double base plate connections

This paper presents a rocking system for concentrically braced frames (CBFs) to mitigate the seismic demands induced by seismic motions. The proposed system incorporates double base plate connections (DBPCs) at the base of the braced-bay columns, enabling them to uplift and initiate a rocking motion. The DBPC comprised two base plates: the upper one is thin, connected to the column and designed to yield under uplift loading, while the lower one primarily distributes compressive loads to the foundation. The DBPC was modeled using a combination of spring and gap elements in SAP2000 software. A comparative study was performed to investigate the seismic performance of the proposed rocking system against a conventional CBF system. Key parameters such as the thickness of the upper base plate and the arrangement of anchor rods were considered. Four prototype frames of different heights (3, 6, 9, and 12 stories) were investigated under the Sylmar-x record using the nonlinear time history analysis. The results demonstrated that utilizing rocking braced frames with double base plate connections can remarkably mitigate the base shear force by softening the structural response, decreasing the seismic damage experienced by the structure. The upper base plate acted similarly to a footing damper, absorbing a substantial amount of energy by yielding. Importantly, the residual drifts caused by the plastic deformations of the upper base plate remained within the acceptable performance limits for self-centering systems. Moreover, the self-centering mechanism was achieved solely through the structure’s self-weight, eliminating the need for additional re-centering devices.

Experimental longitudinal shear testing of novel and traditional shear connectors in double-wythe cavity masonry walls

Double-wythe cavity masonry walls are made of two masonry layers (wythes) – an inner structural wythe typically made from concrete masonry units and an outer façade layer usually made from bricks. Insulation layer and an air gap exist between wythes. Connectors transmit load from the façade to the structural layer. Connectors are typically designed to carry axial forces, but not shear. Their ability to transmit shear, however, is important to achieve composite behaviour between wythes and increase wall capacity under out-of-plane loads. In this study the performance of a novel inclined connector is examined, along with more traditional connectors, through longitudinal shear testing in 38 double-wythe, small-scale specimens. Test parameters include plate connector orientation (horizontal and vertical), tie embedment length, and veneer type (concrete brick, clay brick). The traditional connectors are made of slotted steel plates. The novel connector is also made of slotted steel plates but placed at an inclination in the cavity. The inclination better utilized material making it reach larger stiffness and strength than traditional plate connectors. With the intention of increasing the resistance of the system, ties with various embedment lengths were used with the vertically placed traditional and novel connectors. The stiffness and strength of the novel connector were significantly larger than the vertically and horizontally oriented traditional connector. The larger strength of the inclined connector enables it to be utilized with wider spacing in a full-scale wall compared to a traditional plate connector, leading to potential savings in materials and labour. Failure of the novel connector was a combination of buckling and pullout of the ties, while that of the traditional connector was due to twisting.

Seismic performance of precast concrete sandwich walls with bolt-steel plate connection

The bolt-steel plate connection stands as a dry connection method in precast structures characterized by its simplicity, high efficiency, ease of assembly and disassembly, and environmental protection. Five precast concrete sandwich walls (PCSWs) with glass fiber-reinforced polymer (GFRP) to connect the interior and exterior concrete wythes were designed and tested to investigate the seismic performance of such walls under cyclic loads. Ultra-high performance concrete (UHPC) was used to strengthen the bolt-steel plate connection joint. This study investigated the effect of the sandwich wall between the two bolt-steel plate connection joints, opening, and UHPC on the seismic performance of PCSWs. The findings revealed that the sandwich wall between the two bolt-steel plate connection joints, UHPC, and the interface between UHPC and ordinary concrete had a significant influence on the failure modes, including four failure modes: shear failure of bolt-steel plate connection joint, concrete crushing at the wall toe and through-crack of the shear oblique cracks and horizontal joint, shear failure at the interface between the solid and sandwich walls, and shear failure typified by a "Keyway" configuration. The use of UHPC to strengthen the bolt-steel plate connection area could significantly improve the load-bearing capacity and peak drift ratio. Whether the sandwich wall was used in the non-bolt-steel plate connection area in the horizontal joint zone had minimal influence on both the load-bearing capacity and peak drift ratio. For the walls without UHPC strengthening, the ultimate load and ultimate drift ratio could be increased by using the sandwich wall between the two bolt-steel plate connection areas, however, it was the opposite when UHPC strengthening was used. The paper also compared the sandwich walls with the solid walls, and the results showed that the sandwich wall with bolt-steel plate connections had good seismic performance.

The effect of staged process parameters for flow drill screws on the strength of the connection between carbon fiber-reinforced plastic and aluminum alloy

This article applies flow drill screws (FDS) technology to the connection of dissimilar materials, carbon fiber-reinforced plastic (CFRP) and 6061-T6 aluminum alloy (AA6061-T6), and proposes a method to study the influence of FDS process parameters on the strength of the connection in stages. Based on this method, the optimal process parameters for the connection of this type of plate are explored. Firstly, the mathematical analysis of the process in each stage is conducted, and then the different process parameters in different stages are grouped and tested for the strength of the joint. The optimal process parameters obtained from the previous stage are input into the next stage for further testing, resulting in the highest shear connection strength of 5.98 kN for the FDS connection of CFRP and AA6061-T6 plates. The experimental results show that the influence of different process parameters on the strength of the joint varies in different stages. To improve the connection strength, high speed and low feed force should be selected in the second stage, low speed and low feed force should be selected in the third stage, and the tightening torque should be reasonably selected in the fourth stage.

Seismic performance of RC frame structures with infill CLT shear walls

This paper focuses on the newly proposed RC-CLT hybrid wall systems used in residential buildings. Cyclic loading tests were conducted using 2-storey specimens, to confirm the seismic performance and behavior of the hybrid system and also to investigate the behavior of the RC beams in mid-level and the transmission of shear stress by the CLT wall from upper to lower level. The experimental results showed that CLT could potentially be more superior than RC wall infill in terms of ductility, due to CLT exhibiting higher inter-story drift during shear failure. Furthermore, this study proposes numerical models to simulate the experimental results of the hybrid systems. The RC structural members were modeled using linear elements with MS model inserted at the ends to consider for the N-M interactions. As for the CLT wall, it was modeled using several braced models. The numerical results generally show good agreements with the experimental results. As a result, the numerical model proposed in this study can contribute to better predict the structural behavior of CLT shear wall infilled RC frame with concealed steel plate and drift pin connections.

Connection design method of honeycomb plate-rod composite structure: Experimental study and theoretical analysis

The connection design method of plate-rod composite structure is very important for the cooperative work of plate and rod. In this study, ten kinds of plate-rod composite structures of different connection methods, connection spacings, and plate thicknesses were designed to examine the connection performance of composite structure. The applicable finite element analysis methods of three connection methods were obtained by comparing the calculation results of finite element simplification models. The influence of connection spacing, connector diameter and plate thickness on the connection performance of three connection methods was studied by parametric analysis. The optimized shear bearing capacity formula of three connection methods were proposed based on the connection performance test and the design specifications at home and abroad. The bending bearing capacity formula of composite structure were proposed by theoretical derivation and finite element analysis, and the relevant parameters were fitted by the Backward Propagation (BP) algorithm in neural network. The results shown that the connection performance of Self-Piercing Riveting connection is obviously better than that of one-side bolt and core-pulling rivet connection, and the bearing capacity is increased by about 6 % and 10 %. The connector solid (So-1-1), solid simplified beam (So-3-1 and So-3-2), and shell simplified beam (Q-1) modeling method can better simulate the one-side bolt connection, and the error is within 3 %. The connector solid (So-1-2), solid beam (So-2-1), embedded (So-4-1), and shell simplified beam (Q-1) are suitable for core-pulling rivet connection, and the error is within 5 %. All the finite element analysis simplification methods can accurately simulate the Self-Piercing Riveting connection except for the Q-2, and the error is within 2 %. The bearing capacity of the composite structure increases with the increase of the connector diameter, the decrease of the connection spacing and the increase of the plate thickness. The optimized shear bearing capacity formula are more suitable for practical application, and the error of the bending bearing capacity formula of composite structure is within 5 %, which provides a certain reference for the design of honeycomb plate-rod composite structure and the revision of relevant specifications in the future.

Flexural Behavior of High-Strength Steel and Ultra-High-Performance Fiber-Reinforced Concrete Composite Beams

The flexural performance of steel and concrete composite beams can be further enhanced by utilizing advanced construction materials such as ultra-high performance fiber-reinforced concrete (UHPFRC) and high-strength steel. In this paper, the concept of critical elastic moment resistance is proposed and the equation for its estimation is derived. It was found that the high yield strength of steel calls for a narrow UHPFRC top layer to reach the critical state, whereas this ideal condition is not realistic for composite beams with normal-strength steel and UHPFRC. Small-scale composite beams composed of both high-strength and low-strength steel materials were tested under four-point bending to verify the critical state and performance of different types of connectors. The headed studs and plate connectors were first tested through small-scale push-out tests and then implemented in the composite beam with different spacing. The connection utilizing headed studs with 150 mm spacing performed the best among the three tested specimens in helping reach the critical elastic moment resistance. Finite element analyses of the composite beam were performed based on the estimated material properties under axial and biaxial stress conditions and the results align with the experiment results.

Numerical Model of 3D Printed Joint of Wooden Frame

Regardless of the type of material, 3D printing seems to be an interesting alternative to conventional construction methods. Leaving aside the use of 3D printing systems for concrete or cement composites, the more conventional 3D printing of plastic, metal or other separated materials may also have its hypothetical benefits in the creation of structural joints. For truss structures, such as arch bridges, certain types of joints can be expected that do not always have the same angle between the single-plane load-bearing elements of the structure. In such a case, the use of 3D printing technology for joint fabrication is defensible. In the case of a standard scale and using experience from timber bridges, one would assume that an embedded plate and pin connection would be the appropriate connection form. In contrast, from the point of view of producing smaller physical models, mainly for a deeper understanding of the comparability issues of numerical modelling and experimental testing, it is advantageous to use so-called enveloping timber element connections. The present paper describes the basic process of numerical analysis of a detail of a wooden arch bridge connection made from 3D printed polycarbonate joints.

Seismic Response of Block-Out Column-Base Plate Connections under Axial Compression and Flexure

Seismic Response of Block-Out Column-Base Plate Connections under Axial Compression and Flexure

Analysis and experimental study on the cause of fracture of a Transmission line’s Drainage connecting plate

The transmission line is exposed to the outdoors for a long time, and the operation environment is complex, which makes the line equipment prone to corrosion, wore and heat, etc. The fracture of the drainage plate of the tensioning wire is one of the problems that often occur in the operation of the transmission line. Based on the systematic analysis of the problem of the fracture of the drainage plate of a transmission line, the causes of the fracture of the drainage plate are obtained, and the corresponding rectification measures are proposed, which has an important reference for the design, construction, operation and maintenance of the subsequent transmission line.

Research on Tensile Test of Dissimilar Steel Body Solder Joints

With 22 mnb5 St16 and ordinary steel as the research object, under the conditions of medium frequency spot welding connection plate welding, solder joint for the electric logging under shear load test, determination of solder joints, solder joint and away from the solder joint around the base of strain, according to measurement data analysis of solder joints and the deformation regularity of parent metal. The test results show that the strain in the spot welding joint distribution is uneven, the center of the welding strain is small, large deformation mainly exist in the heat affected zone, near the solder heat affected zone is the main area prone to give in. Away from the solder joint area of the parent metal, the influence of solder joint is small, mainly tensile strain, and strain as the load increases, solder joint strain is negative, the center is linear, and basic antisymmetric location of strain values different test points.

An agent-based heuristics optimisation model for production scheduling of make-to-stock connector plates manufacturing systems

The manufacturing systems’ success directly relates to their accurate, reliable and flexible schedules, including how production is planned and scheduled and which constraints are considered in generating the schedules. The study's objective arises from the need to generate an optimal production scheduling system in a connecting plates manufacturing company that works on a Make-To-Stock basis. This research investigates the impact of demand and operational constraints on production schedules, including the facility capacity, operators and machines availability, raw materials availability, inventory level and warehouse capacity. A multi-agent-based optimisation model is developed to face the complexity of considering demand and operational constraints and reflects their impact on generating a reliable production schedule. This model involves a proposed heuristic algorithm that considers demand and operations constraints in such a manufacturing environment and optimises the production schedule based on these restrictions/requirements. A real-life case study based on a connecting plates manufacturer company is used as a test bench of the proposed agent-based heuristic optimisation model. The proposed algorithm is compared with other related approaches to check its superiority based on key criteria, including inventory levels, missed/unsatisfied orders and total production time. Results show that the proposed heuristics algorithm reduced the number of missed orders by 34% compared with similar approaches.

Experimental investigation and evaluation of metal-plate-connected laminated bamboo lumber joints

This study focused on the mechanical performance of toothed metal-plate connected (MPC) laminated bamboo lumber (LBL) joints aiming to apply this metal-plate connection to the design and manufacturing of engineered bamboo trusses, due to the merits of the cost-effective and easy installation. A total of 212 MPC LBL and SPF (spruce-pine-fir) joints connected by the domestic toothed metal plates were tested in accordance with Chinese standards. Particular emphasis was placed on the load-slip behavior of metal plate teeth embedded in LBL with varied load direction related to the major axis of the toothed metal plate. Design values of the tensile and shear strength of the net section cross metal plate connector, and the anchorage and anti-slip strengths of the metal plate teeth embedded in LBL were presented in accordance with the existing timber design specification. Test results reveal that the metal plate orientation has a significant effect on the mechanical performance of MPC LBL joints. A new angular equation, expressed as the metal plate orientation, was proposed for evaluating the anchorage and anti-slip strengths of MPC LBL joints, which shows an obvious reduction in predicting error compared with the existing method. Design strength values of LBL joints are higher than those of the corresponding SPF joints, mainly due to the relatively smaller dispersion of LBL compared with SPF, indicating that the MPC LBL is expected to replace MPC timber in truss systems. The results of the comparison of MPC LBL and glubam (glued laminated bamboo) joints also suggest that arranging transverse bamboo strips is an available option for improving the anchoring mechanical performance of MPC LBL joints.