Capacity Of Joints Research Articles

Reinforcement learning for dynamic pricing and capacity allocation in monetized customer wait-skipping services

ABSTRACT We consider how to facilitate a dynamically-priced premium service option that enables customer parties to shorten their wait in a queue. Offering such a service requires that some of a business’s capacity be reserved continuously and kept ready for premium customers. In tandem with capacity reservation, pricing must be coordinated. Hence, a joint dynamic pricing and capacity allocation problem lies at the heart of this service. We propose a conceptual solution architecture and employ Proximal Policy Optimization (PPO) for dynamic pricing and capacity allocation to maximize total revenue. Simulation experiments over multiple scenarios compared PPO against a human-engineered policy and a baseline policy having no premium option. The human-engineered policy led to significantly greater revenues than the baseline policy in each scenario, illustrating the potential increase in revenues afforded by this concept. The PPO agent substantially improved upon the human-engineered policy advantage, with improvements ranging from 28% to 161%.

Prediction of Strength and Failure Modes in Reinforced Concrete Beam–Column Joints using Ensemble Machine Learning Techniques

The beam-column joint is one of the important structural elements that control the structural behaviour during seismic excitation. Moreover, failure of any of these components may lead to the partial or overall collapse of the entire structure. In view of the safety concern, there is a need to evaluate the response properties, such as failure modes and ultimate shear capacity of the beam-column joints. Conventional methods to evaluate the shear capacity of beam-column joints are usually time-consuming. Therefore, in this study, an attempt has been made to evaluate the joint shear capacity and mode of failure of an exterior beam-column joint using ensembled machine learning (ML) approaches like Decision Tree, Random Forest, AdaBoost, CatBoost, and LightGBM. The present study highlights the potential use of the CatBoost model as a useful tool that can assist in predicting the shear strength and failure mode. The results of the study reveal that this model has performed well in predicting the load-carrying capacity and shear strength with high correlation coefficients of 0.9836 and 0.9978, respectively. Moreover, it has been observed that the prediction model provided by the CatBoost algorithm exhibits the highest accuracy for classification in the failure mode of beam-column joints.

The Influences of Selected Factors on Bending Moment Capacity of Case Furniture Joints

This study experimentally investigated the effects of selected factors on the bending moment capacity (BMC) of case furniture joints. The main aim was to explore mixed applications of wood-based materials and fasteners in manufacturing case furniture to reduce material costs. The study examined the effects of the face member material—particle board (PB), plywood (PL), and block board (BB)—edge member material (PB, PL, and BB), and joint shape (T-shape and L-shape) on BMC. Additionally, the study evaluated the effects of joint type (two eccentrics (TE), two dowels (TD), and one eccentric and one dowel (ED)), and material type (PB, PL, and BB) on BMC for L-shaped joints. The results showed that joint shape and face member material significantly affected the BMC of case furniture joint. The BMCs of T-shaped joints were significantly greater than those of L-shaped joints, regardless of the material of the face and edge members, except when the face member was made of PL. For L-shaped joints with PL face members, the BMCs were significantly higher compared to others. Joints constructed with TE exhibited significantly higher BMC compared to ED and TD for the same material type. For PB, TE joints exhibited an increase of approximately 3.0 Nm and 2.0 Nm compared to TD and ED, respectively. For PL, TE showed an increase of 9.1 Nm and 4.1 Nm compared to ED and TD, respectively. For BB, the increases were 7.0 Nm and 6.6 Nm compared to ED and TD. The BMC of joints made with PL and constructed with TE and ED was significantly greater than those of BB, followed by PB. However, for joints assembled with TD, there was no significant difference among the three materials. The ratios of BMC for joints constructed with ED compared to the half-sum of TE and TD were 0.73, 1.04, and 0.79 for PB, PL, and BB, respectively. These results suggest that the face member material predominantly influences the BMC of case furniture joints, indicating the potential to reduce costs by combining different materials and joint types.

Seismic performance of mortise-tenon joint in prefabricated platform canopy

To optimize the prefabricated canopy joints, improve the construction efficiency, and enhance the seismic performance of assembly joints, a novel mortise-tenon joint (MTJ) was proposed. To evaluate the seismic performance along the vertical and track directions, two 1:1.5 scaled specimens were tested under low-cycle reciprocated loading. The test results find the hysteretic curves in both directions exhibit the “pinch” effect especially in the vertical direction, indicating the feature of shear slippage. The displacement ductility coefficients were all above 5.0, and the ultimate drift ratios were 4.54% and 5.88% respectively, showing excellent deformation ability and ductility. The parameters, such as the sectional strength ratio, the stirrup ratio of the prefabricated beam, the reinforcement ratio and the cross-sectional area of the enlarged section, were analyzed by the validated finite element (FE) models. The analysis shows as the section strength ratio decreases and the stirrup ratio increased, the seismic bearing capacity improved, while the plastic hinge located on the prefabricated column varied to the prefabricated beam ends. Based on the results, it is recommended the number of longitudinal rebars through the prefabricated beam is 4, the stirrup diameter in the prefabricated beam is 10mm and the the column cap is no less than 400mm. Finally, based on the truss-diagonal strut model, a method for calculating the shear strength capacity of the novel joint was proposed. Compared with the test and FE results, the theoretical equations exhibit good computational accuracy.

Research on flexural behavior and design method of formwork free UHPC wet joint in prefabricated small box girder bridges

This study aims to enhance the bearing capacity of wet joints in prefabricated small box girder bridges while simplifying the on-site construction process. Experimental tests were conducted on formwork-free ultra-high-performance concrete (UHPC) wet joints, focusing on failure modes, ultimate flexural capacities, and cracking and strain behaviors. These were compared to the behaviors observed in rectangular and funnel-shaped wet joints. The results demonstrate that the width of the joint significantly influences flexural performance, with the horizontal strip playing a crucial role in resisting cracks. It is recommended that for formwork-free UHPC wet joints, the strip height h2 should be no less than 0.1 times the thickness of the bridge deck, and the joint width W should be at least eight times the diameter of the transverse steel reinforcement. Considering the contribution of UHPC in the tensile zone, formulas were developed to calculate the flexural capacity of UHPC-normal concrete (NC) composite section beams. Based on these flexural test results and numerical analysis, a design method for formwork-free UHPC wet joints is proposed.

7.G. Round table: Primary prevention and management of NCDs – the added value of joint actions across Europe

Abstract Two ambitious European joint action projects, funded through the EU4Health programme, are ongoing to reduce the burden of non-communicable diseases (NCDs) and related risk factors in Europe, targeting both individual and societal levels. Together, these projects aim to scale up effective prevention and management strategies, strengthen public health policies and promote equitable and sustainable healthcare systems across Europe. The Joint Action on CARdiovascular Diseases and DIabetes (JACARDI), with 21 participating countries and a total budget of over €66 million, is focusing on enhancing the implementation of evidence-based innovative pilot projects across the entire patient journey. This includes efforts to improve prevention, early diagnosis, and proactive management of NCDs. The Joint Action Prevent Non-Communicable Diseases (JA PreventNCD), with 25 participating countries and a total budget of over €95 million, particularly aims to enhance joint capacities of countries for implementing, scaling up and evaluating prevention policies and actions at various levels. These projects represent complementary responses to calls for action in Europe’s Beating Cancer Plan and the Healthier Together - EU NCD Initiative, with JA PreventNCD emphasizing primary prevention and policy while JACARDI focuses on secondary prevention and health systems strengthening. Both projects will generate new policy-relevant evidence based on implementation, monitoring and scaling-up of best and innovative practices and policies across Europe. The projects share a focus on equity, diversity, scalability and sustainability, while avoiding fragmentation and duplication of actions. Under the EU4Health programme, launched to strengthen European health collaboration in the wake of the COVID-19 pandemic, the EU has recently invested over €200 million in public health initiatives, with additional investments from national authorities participating in the joint actions. With this new wave of funding, real population impact should be anticipated, but what can we realistically expect to be the outcomes and what are the criteria for success? In this round table discussion 1) these two joint action projects will be presented, highlighting their innovative aspects; 2) views on the added value and potential in cross-national collaborations for prevention and management of NCDs will be debated, and 3) how synergies will be leveraged for maximum impact will be explored. Panelists will share their perspectives on the projects’ potential to change the public health landscape in Europe. Workshop participants will subsequently be encouraged to engage in the discussion with the objective that views and experiences are exchanged, opportunities for collaboration and engagement are shared and energy is mobilized to harness the benefits of such large-scale policy-relevant collaborations. Key messages • Synergies and collaboration to drive policy development and foster increased capacity are the pillars to build a healthier Europe. • Two large-scale Joint Actions drive impact by highlighting innovative NCD prevention strategies and fostering collaborative engagement.

Performance of SRC unequal-depth beam-column irregular joint in NPP under progressive collapse

The prototype structure of this study is taken from the main shield building of nuclear power plant (NPP) conventional island facilities. Emphasis is on steel reinforced concrete (SRC) unequal-depth beam-column irregular joints, studying their resistance to progressive collapse via analysis of two 1/5 scale irregular joints. Vertical monotonic loading tests were conducted on the joints, followed by numerical simulations to analyze their mechanical properties, failure modes, and progressive collapse resistance. Experimental analyses focused on irregular joint failure modes, central column load changes with displacement, beam deformations, strain variations in critical sections, and resistance mechanism development. Finite element (FE) software modeled these behaviors and was validated against experimental data. Then, according to the various beam section depths of the connected beams, this research applied the validated numerical models to examine the load-bearing capacity of the irregular joints. The results indicate that the damage of the unequal-depth beam-column irregular joint exhibits significant asymmetric characteristics. In terms of load performance, the performance of the irregular joint depends on the component performance of the shallow beam section. Within a certain range, the greater the height difference between the various beams, the greater the joint bearing capacity, but the stability of the bearing performance deteriorates. The fracture yield of H-shaped steel significantly reduces the bearing capacity, and it is recommended to reinforce shallow beams. Providing data reference for the design of the irregular joints has important practical significance.

Experimental and numerical investigations on flexural behavior of apex joints in aluminum alloy portal frames

Aluminum alloy portal frames (AAPFs) find extensive applications in lightweight and temporary structures owing to their light weight, excellent corrosion resistance, and ease of installation and disassembly. Existing design equations for cold-formed steel portal frame (CFSPF) apex joints are not applicable to AAPF apex joints due to significant differences in structural configuration. Therefore, dedicated research is needed to develop design guidelines for AAPF apex joints. Consequently, this paper conducts experimental and numerical investigations on flexural behavior of AAPF apex joints. Initially, bending tests are conducted on three AAPF apex joints, revealing failure modes including clamping plate buckling and beam failure. The flexural behavior of apex joints throughout the entire process is analyzed based on moment-rotation curves and moment-strain curves. Subsequently, finite element (FE) models are established and validated by comparing the FE results with the experimental results. Following this validation, parameter analysis is conducted considering the influence of beam cross-sectional dimensions, clamping plate dimensions, bolt dimensions, and layout. Finally, based on theoretical and numerical investigation, the calculation equation for the flexural capacity of AAPF joints is derived, offering valuable reference for engineering design.

Parametric study on the load-carrying capacity of plain-woven composites hybrid bonded-bolted joints

This work presents procedures and results from quasi-static uniaxial tensile experiments carried out on hybrid bolted bonded (HBB) joints using carbon fibre reinforced plastic (CFRP) adherends. The impact of various dimensional parameters, including lap length (L), lap width (W), number of bolts ( N), bolt diameter (D), and bolt arrangement, on its ultimate load and failure modes of the HBB joint is investigated. The failure mechanism of the HBB joint is examined and summarized, offering theoretical insights for the engineering application of this structural configuration. The findings of the study indicate that the ultimate load capacity of the hybrid joint is notably enhanced by increasing both the lap length and lap width, and is further influenced by the effective dimensions at the edges and end distances. The transverse configuration of multiple bolts within the adhesive-bolt hybrid joint demonstrates superior maximum load capacity and average stiffness in comparison to a longitudinal arrangement. During tensile testing, the primary mode of failure observed in the Hybrid Bolted-Bonded (HBB) joint is adhesive failure, often accompanied by delamination. Cleavage failure is predominantly observed in configurations with longitudinally aligned multiple bolts arranged in a singular row. On the other hand, shear tear-out and bearing failures are commonly encountered in single-bolt joints characterized by a substantial width-to-diameter (W/D) ratio. Specifically, shear tear-out failure tends to manifest in cases with a small length-to-diameter (L/D) ratio, whereas bearing failure is more prevalent in instances with a large L/D ratio.

Optimization of Shear Resistance in Horizontal Joints of Prefabricated Shear Walls through Post-Cast Epoxy Resin Concrete Applications

The horizontal joint is a critical component of the prefabricated shear wall structure, responsible for supporting both horizontal shear forces and vertical loads along with the wall, thereby influencing the overall structural performance. This study employs direct shear testing and finite element analysis to investigate the horizontal joint in walls with ring reinforcement. It examines the impact of various factors on joint shear performance, including the type of joint material, joint configuration, buckling length of ring reinforcement, strength of precast concrete, reinforcement ratio of ring reinforcement and dowel bars, and the effect of horizontal binding force. The findings indicate that the shear bearing capacity and stiffness of joints incorporating post-cast epoxy resin concrete and keyways are comparable or superior to those of integrally cast specimens. A larger buckling length in ring reinforcement may reduce shear strength, suggesting an optimal buckling length at approximately one-third of the joint width. As the strength of precast concrete increases, ductility decreases while bearing capacity increases, initially at an increasing rate that subsequently declines. Optimal results are achieved when the strength of precast concrete closely matches that of the post-cast epoxy concrete. Enhancing the reinforcement ratio of ring reinforcement improves shear capacity, but excessively high ratios significantly reduce ductility. It is recommended that the diameter of ring reinforcement be maintained between 10 mm and 12 mm, with a reinforcement ratio between 0.79% and 1.13%. Increasing horizontal restraint enhances stiffness and shear capacity but reduces ductility; thus, the axial compression ratio should not exceed 0.5.

Experimental study on bearing capacity performance of glued bamboo-wood bolted joints

The paper presented an experimental investigation of glued bamboo-timber bolted joints to study the influence of bolt grade, bolt diameter, and material type on the load-bearing capacity of bolted joints. The results showed that the failure mode of glued bamboo-timber bolted joints was characterized by compression deformation of the bolt holes, with a plastic hinge failure occurring at each shear plane. Additionally, the failure of the specimens involved the failure of both the primary material and the adjacent substrate at the edge of the joint. As the diameter of the bolts increased, the load-bearing capacity of the specimens also increased. The increase in maximum load from a bolt diameter of 10 mm to 12 mm was 13.78 %, while the increase in maximum load from a bolt diameter of 12 mm to 14 mm was 42.29 %. Enhancing the bolt grade increased the load-bearing capacity of the specimens. The increase could be 10.32 % under the circumstance of WBW (wood on the outer layer and bamboo on the inner layer) combination while 8.4 % when it was BWB (bamboo on the outer layer and wood on the inner layer) combination. Moreover, when the material type was changed into BWB, the increase in load-bearing capacity was 55.33 % and 32.84 % when the diameter varies. The load-bearing capacity of the BWB material was higher than that of the WBW material. After comparing the existing methods of calculating bolt load carrying capacity, optimizations were made to the calculation formulas in Eurocode 5. The modified formula provided more accurate predictions of the load-bearing capacity of glued bamboo-timber bolted joints.

Seismic behavior of exterior joint of CFDST column to steel beam with RC slab

To investigate the seismic performance of an exterior joint connecting concrete-filled double-skin steel tubular (CFDST) column to steel beam with reinforced concrete (RC) slab, four scaled-down joint specimens were designed at a ratio of 1:2. Quasi-static tests were conducted with different axial compression ratios were performed, and the failure mode, hysteresis curve, skeleton curve, bearing capacity, energy dissipation capacity, strength and stiffness degradation, and strain analysis of the composite joint were analyzed. A finite element method (FEM) model of the joint was constructed and validated against the obtained experimental results. Additionally, a parametric study was carried out to investigate the influence of various factors, including the hollow ratio of the CFDST column, the concrete strength of the slab, the thickness of the slab, and the width-to-thickness ratio of the outer steel tube on joint. Based on experimental studies and finite element analysis (FEA), a theoretical calculation method was proposed to evaluate the flexural capacity of the composite joints. The test results showed that the composite exterior joint specimens with RC slab failed at the beam end. Typical failure phenomena of fracture at the steel beam and horizontal end plate interfaces, steel beam flange buckling, and concrete crushing at the RC slab were observed in the experiments. While the interior joint specimen experienced significant plastic deformation and buckling at the column flange. The hysteresis curve of the specimen is elliptical and full without pinching. The presence of RC slab can effectively improve the ultimate bearing capacity, initial stiffness and energy dissipation capacity of the specimen. The FEA results show that the bearing capacity of the composite joints was improved significantly with the increase of the thickness of the slab and the width-thickness ratio of the outer steel tube. The theoretical calculation results of the flexural capacity of the joint are 86 %–112 % of the results of the finite element calculation. The stability and accuracy of the calculation method are excellent and can be effectively applied to calculate the flexural capacity in CFDST composite structural systems.

Seismic performance of earthquake-damaged HSRAC beam-column interior joints rehabilitated by bonding steel plates in the plastic hinge of beams

In order to investigate the seismic performance of earthquake-damaged high-strength recycled aggregate concrete (HSRAC) beam-column interior joints employing ultra-high strength bars (UHSB) in columns, four specimens were designed and manufactured. The research variables included whether the steel tube was encased in the column and whether beams were rehabilitated by bonding steel plates. Among them, the rehabilitated specimens were firstly loaded to 1.0 % drift ratio, and then loaded to failure after rehabilitating the plastic hinge of beams. The test results showed that the beam hinge failure mode occurred in the specimens loaded directly to failure. The damage of columns and joint cores was relatively slight, and the crack width satisfied the repairability limits before 2.0 % drift ratio. The shear failure of the joint core occurred in the rehabilitated specimen without steel tube, as shear deformation and stirrup strain in the joint core increased. The shear bearing capacity of joints increased after steel tubes were encased in columns, and the damage of joint cores was reduced. The bearing capacity and deformation capacity of specimens improved after rehabilitating. Finite element models were established and verified with experiment results. Parameter analysis was conducted for different pre-damage degrees, and the results indicated that as pre-damage degree increased, the bearing capacity of specimens decreased.

Failure mechanism and plastic hinge of RC joints under impact load acting on column ends

Impact loads often act on columns end during accidents such as vehicle impacts and terrorist attacks. The resulting deformations lead to a redistribution of internal forces in the member as well as a reduction in the load carrying capacity. The integrity of the core area of the joint is threatened, which could trigger a progressive collapse. This study numerically investigated the damage and deformation of reinforced concrete (RC) beam-column joints when they are impacted on the column end. The resistance mechanism of joints and the influence of impact location as well as impact velocity was explored. Besides, the deformation capacity of RC beam-column joints under impact loading was quantified using equivalent plastic hinges. It was found that the damage and plastic deformation is concentrated at the impacted column end. The horizontal reaction force at the beam end provides resistance and plays the role as a bearing. The column bottom reaction force is in the same direction as the impact force. However, it is much smaller than the beam end reaction force. The resistance mechanisms within the joints can be categorized into strut-and-tie near the loading point and arches in the mid-span of the beam and column. The core area rotates and has a significant lateral displacement towards the impact location, whether it is loaded at the beam end or the column end. As the impact location moves away from the core aera, the impacted column end exhibit more bending failure. With increasing impact velocity, the impact force, reaction force and total energy absorption of the joint increase. The deformation increases, with more damage occurring in the core area and spreading to the beam. In addition, the plastic curvature was used to describe the actual plastic deformation of the joints, whose maximum occurring at the interface where the impacted column end meets the core area. A formula for the equivalent plastic hinge length of RC joints was proposed, taking into account the effects of impact location and impact velocity.

Mechanical Performances of Concrete-Filled Steel Pipe Composite Segments in Complex Geological Conditions

When shield tunnels are under complex geological conditions, tunnel damage, decreased structural performance, and shield tunnel deformation and destruction may occur. Therefore, a new type of composite segment and combined splicing joint were suggested and experimentally investigated in this study. According to the test results, the new composite segment effectively enhanced the load capacity of the segment, and the yield and ultimate loads of the segment were increased. Compared with the reference specimen, the ultimate load capacities of the proposed segments with different numbers were 23.8%, 50.0%, and 64.3% greater. Moreover, the combined splicing joint enhanced the initial bending stiffness and load capacity of the segment joint, reduced the opening displacement, and improved the rotational stiffness of the segment joint. The addition of a plug-in joint at the segment joint increased its load capacity by approximately 25%. A parametric study showed that the number and posit ion of the plug-in joint clearly affected the load capacity of the segment joint. In addition to the above test results, reasonable theoretical formulas for the new composite segment and combined splicing joint are given in this paper.

Experimental study on shear mechanical properties of concrete joints under different unloading stress paths

In order to study the shear mechanical properties of rock joint under different unloading stress paths, the RDS-200 rock joint shear test system was used to carry out direct shear tests on concrete joint specimens with five different morphologies under the CNL path and different unloading stress paths. The unloading stress paths include unloading normal load and maintaining constant shear load (UNLCSL), unloading normal load and unloading shear load (UNLUSL), unloading normal load and increasing shear load (UNLISL). The results show that the peak shear strength, cohesion, internal friction angle, pre-peak shear stiffness and residual shear strength of concrete joints under CNL path increases with the increasing JRC and normal stress. Under the UNLCSL path, under the same initial shear stress τ1, instability normal stress σi decreases with the increasing JRC, and normal stress unloading amount Δσn increases with the increasing JRC. Under the same JRC, σi increases with the increase of τ1, and Δσn decreases with the increasing τ1. Under the same JRC and σi, τi is significantly smaller under the UNLCSL path than the CNL path. Under the same JRC, the cohesion under the UNLCSL path is less than the CNL path, and the internal friction angle is higher than that the CNL path. Under the same JRC and σi, τi is the largest under the path of CNL and UNLISL, followed by the UNLCSL path, and τi under the UNLUSL path is the smallest. Compared with the CNL path, the variation range of the specimen internal friction angle is within 3% while the average decrease percentage of the specimen cohesion reaches 37.6% under the UNLCSL path, UNLISL, and UNLUSL. Therefore, it can be inferred that the decrease in cohesion caused by normal unloading is the main reason for the decrease in joint instability shear strength. After introducing the correction coefficient k of cohesion to modify the Mohr-Coulomb criterion, the maximum average relative error after correction is only 3.5%, which is significantly improved compared with the maximum average relative error of 56.9% before correction. The research conclusions can provide some reference for the accurate estimation of shear bearing capacity of rock joints under different unloading stress paths, which is of great significance to the stability evaluation and disaster prevention of rock mass engineering.

Ultrasound-guided combined intra-articular corticosteroids injection and suprascapular nerve block for pain control in patients with frozen shoulder

BackgroundFrozen shoulder is an incapacitating disease that causes pain and limitation in the shoulder joint functional capacity. This work aimed to assess the efficacy of ultrasound-guided combined intra-articular corticosteroids (CS) injection and suprascapular nerve block (SSNB) in pain control in patients with frozen shoulders.ResultsOur prospective study included 40 patients, equally divided into two groups: group A; managed with combined ultrasound (US) guided intra-articular corticosteroids injection (IACSI) and SSNB, and group B patients managed with US-guided SSNB. The visual analog scale score statistically significantly improved after both injections. This success was maintained and showed mild improvement at 8-week intervals (with increased patient capability to do physiotherapy after pain control). Similarly, improvement in the functional capacity of the shoulder joint was identified and assessed by the Oxford shoulder score (OSS) in both groups. Mean OSS was statistically significantly higher at 4-week intervals than before the nerve block for groups A and B. At 8 weeks interval, this favorable result was sustained (p < .001).ConclusionsUS-guided SSNB is an effective, radiation-free method to alleviate frozen shoulder-related pains. However, US-guided combined SSNB and IACSI was more effective than SSNB alone in both pain alleviation and improved shoulder joint function.

Experimental Study on the Bending Behavior of Precast Concrete Segmental Bridges with Continuous Rebars at Joints

Longitudinal ordinary rebars are discontinuous at the joints of precast concrete segmental bridges (PCSBs), which can open under tensile stresses induced by bending moments. This will lead to durability issues with the joints. To improve the bending properties of PCSBs, a novel joint type featuring continuous rebars was proposed in the present study. Three specimens were subjected to testing to examine the bending behavior of PCSBs using this new joint design compared to traditional joints. The crack propagation, structural deformation, joint opening width, strain in rebars, failure mode, stiffness, and flexural capacity were comprehensively investigated. The test results reveal that the continuous rebars effectively transferred bending normal stress between joints, ensuring full development of cracks in each beam segment. Effective control of joint opening width was also observed. Compared to traditional joints, the new joints exhibited a 29% to 33% increase in cracking load and a 32% increase in ultimate load. Failure in the continuous rebar joints was characterized by partial anchorage failure of the rebars along with localized concrete crushing in the top compression zone. Based on the test results, a computational method was proposed for calculating the cracking strength and flexural capacity of the new joints.

Development of a new analytical model for circular concrete ring segments with dry joints under combined effects

AbstractPrevious models of circular ring segment joints have been inadequate in describing their loading capacity due to the lack of consideration for the interaction between shear force and bending moment. Consequently, these models have led to over‐ or underestimation of the joints' capacity. The increasing use of dry joint connection technology in wind turbine towers and prefabricated segmental bridge constructions necessitates the development of advanced computational models for these connections. This study presents a new model that considers the effects of bending moment, shear force, and torsion on the loading capacity of circular ring segment joints. Numerical simulations were conducted to validate the developed model under different load combinations, and the results demonstrate excellent agreement between the model predictions and numerical simulations.

Glenohumeral Joint Volume Measurement in Patients with Shoulder Instability: A 3D Volumetric Magnetic Resonance Arthrographic Study.

Background and Objectives: This study aimed to compare capsular volume in patients with shoulder instability to that in control subjects without instability using magnetic resonance (MR) arthrography. The objective was to develop a reliable screening method with which to assess shoulder volume. Materials and Methods: In 21 patients with atraumatic shoulder instability and 21 controls, thin-slice 3D volumetric MR arthrography sequences were obtained. MR arthrography images were uploaded to 3D reconstruction, and 3D images were generated. From the 3D reconstructed images, volumetric measurements of rotator interval (RI), anterior and posterior capsular (AC, PC) recesses, biceps tendon sheath (BS), axillary recess (AR), and total glenohumeral joint (TGJ) were performed. Individuals with any extra-articular contrast leakage were also recorded. Results: A retrospective study analyzed a patient group of 21 individuals with shoulder instability (mean age 29.52 ± 12.83 years) and a control group of 21 individuals without instability (mean age 35.71 ± 12.77 years). No statistically significant differences were identified between the groups with regard to age, gender, or side distribution. The mean total joint volume was significantly higher in the instability group (29.85 ± 6.40 cm3) compared to the control group (23.15 ± 3.48 cm3, p = 0.0001). Additionally, the mean volumes of the RI, AC, PC, BS, and AR were all significantly greater in the patient group compared to the control group. Conclusions: 3D volumetric MR arthrographic measurements of the shoulder joint capacity can provide valuable insights for clinical follow-up and guide surgical treatment decisions in cases of atraumatic shoulder instability.