Core Reinforcement Research Articles

Analysis on Mechanical Properties of FRP Constrained Concrete Core Reinforcement Under Cyclic Load

This article aims to analyse the mechanical properties of FRP confined concrete core rods under cyclic loading. By observing the behaviour characteristics of FRP confined concrete core rods under different cyclic loads, the influence of FRP confinement on concrete cyclic loading is analysed. Based on theoretical analysis, this article establishes a corresponding mechanical model and analyses the response mechanism of FRP constraints to concrete cyclic loads through simulation calculations. Through experimental research and theoretical analysis, it is possible to fully understand the performance of new composite structural materials. The research results of this article indicate that the confinement of FRP bars can significantly improve the compressive strength of concrete specimens. At a constraint ratio of 20%, the compressive strength of the specimen increased by 30% compared to the unconstrained ratio; At 40%, the compressive strength increased by 50%, therefore, FRP confinement can significantly improve the ductility of concrete and reduce fatigue damage under cyclic loading. Through this research method, important evidence can be provided for the application of concrete in practical engineering.

Reinforcement Learning Review: Past Acts, Present Facts and Future Prospects

Reinforcement Learning (RL) is fast gaining traction as a major branch of machine learning, its applications have expanded well beyond its typical usage in games. Several subfields of reinforcement learning like deep reinforcement learning and multi-agent reinforcement learning are also expanding rapidly. This paper provides an extensive review on the field from the point of view of Machine Learning (ML). It begins by providing a historical perspective on the field then proceeds to lay a theoretical background on the field. It further discusses core reinforcement learning problems and approaches taken by different subfields before discussing the state of the art in the field. An inexhaustive list of applications of reinforcement learning is provided and their practicability and scalability assessed. The paper concludes by highlighting some open areas or issues in the field

Efficacy of Core Strength Exercises in Enhancing Rebound Jump Performance in Martial Arts Athletes

Background and Aim: Core strength exercises have become a focus in sports performance and injury prevention research. The core muscles, which include the diaphragm, abdominal muscles, and pelvic floor muscles, are instrumental in providing stability and power during athletic activities. The study focuses on the impact of core strength exercises on specific performance metrics—namely, the standing long jump and rebound jump—in martial arts athletes. Materials and Methods: The study employs a structured, eight-week intervention program to investigate the effects of core exercises on martial arts athletic performance. The study involves forty student-athletes from Guangzhou Sport University, divided into an Experimental Group (EG) and a Control Group (CG). Various physical tests are conducted both pre- and post-intervention to measure the effects. Statistical analyses, including Two-way ANOVA, are used to interpret the data. Result： For the standing long jump, the Two-way ANOVA showed no significant effect of training (F=1.129, p=0.291) or time point (F=0.587, p=0.446). Effect sizes, measured by Cohen's d, indicate a slight benefit in the core reinforcement group with a value of d=0.425, compared to d=0.111 in the non-reinforcement group. In the case of the rebound jump index, there is a pronounced effect from the group (F=4.92, p=0.03) and the time point (F=105.97, p<0.001). Large effect sizes were observed, with d=2.5522 for the core reinforcement group and d=2.0457 for the no core reinforcement group. Conclusion: For standing Long Jump: Given the absence of a significant impact of core reinforcement on this metric, coaches, and athletes might consider incorporating other methodologies, such as plyometrics or attentional focus strategies, into their training regimen. For the rebound Jump Index: Core reinforcement exercises should be strongly considered for inclusion in warm-up routines for martial arts athletes, given the substantial effect size observed.

The Effect of Reinforce Powder Size on The Properties of Pineapple Leaf Fiber – Bagasse Sandwich Composites

The growth of ship production in Indonesia encourages the shipping industry to utilize the composite material in order to be more efficient. Natural fibre-reinforced composite (NFRC) is one option that should be considered for use safer than fiberglass. The usage of fiberglass could trigger several health problems. Sugarcane and pineapples are one of the most common agricultural commodities, yet their waste has not been treated optimally. This research is going to analyse the effect of reinforcement powder size on its bending strength in pineapple leaf fibre – bagasse reinforced sandwich composites. Pineapple leaf fibre use as skin reinforcement whereas bagasse use as core reinforcement. Sandwich composites were reviewed for their bending strength on specimens on reinforcement powder size 40, 60, and 100 mesh. The composite was made using the hand lay-up method with skin composition is 20:80% and core composition is 25:75%, each layer of skin and core have 2 mm thickness. The highest bending strength for sandwich composite is 52,72±0,85 MPa as a result of the experiment using 100 mesh of reinforcement powder. The bending strength of sandwich composite increase as finer particle powder use for the reinforcement. The highest bending strength in this study can be used as bulkhead material for the interior of the ship’s accommodation space based on SNI 01-4449-2006.

Evaluation of fracture behavior in short fiber–reinforced direct and indirect overlay restorations

ObjectivesThe aim was to assess how incorporating a short-fiber composite (SFC) core would affect the fracture behavior of direct and indirect overlays. Furthermore, to examine the relationship between the thickness ratio of SFC core to particulate-filled composite (PFC) veneering and the fracture-behavior of bilayered-structured restorations.Materials and methodsA total of 120 molars were used to create MOD cavities, with palatal cusps removed. Four different groups of direct overlays were then made (n = 15/group), all of which featured a SFC core (everX Flow) with varying thicknesses (0, 1, 4, and 5 mm), as well as a surface layer of PFC (G-aenial Posterior), with the overall thickness of the bilayered-structured restoration set at 5 mm. Additionally, four groups of CAD/CAM restorations were created (Cerasmart 270 and Initial LiSi Block), with or without 2 mm of SFC core reinforcement. Following the fabrication of these restorations, cyclic fatigue aging was carried out for a total of 500,000 cycles, with an applied maximum load (Fmax) of 150 N. Subsequently, each restoration underwent quasi-static loading until fracture. The fracture mode was subsequently evaluated using optical microscopy and SEM.ResultsThere were no statistically significant differences (p > 0.05) observed in the fracture resistance of indirect overlays reinforced with a 2-mm SFC core compared to those made solely from restorative materials. Direct overlays constructed using plain SFC or with a 4-mm layer thickness of SFC core exhibited significantly higher fracture resistance values (2674 ± 465 and 2537 ± 561 N) (p < 0.05) when compared to all other groups tested, according to the statistical analysis ANOVA.ConclusionsThe most effective method for restoring large MOD cavities was found to be direct restoration using SFC either alone or as a bulk core in combination with PFC composite.Clinical relevanceThe use of SFC as bulk reinforcing base will significantly improve the loading performance of directly layered restorations.

Quasi-Static and Fatigue Properties of Thermoset Sandwiches with 3D Continuous Fibre Reinforced Polyurethane Foam Core.

Innovative materials for substituting metals are required to reduce the mass of moving components. This decreases the CO2 emissions of overall systems. A thermoset sandwich for high mechanical properties and thermal insulation is presented in this paper. It has an innovative 3D continuous reinforced core, which allows the optimisation of the substance exploitation by wide-ranging possibilities of fibre orientation. This was demonstrated with three sandwich variants. The reference had no core reinforcement and the other two were reinforced with different spacer fabrics. The process chain for the manufacturing consists of Structural Reaction Injection Moulding (SRIM) and Vacuum Assisted Resin Transfer Moulding (VARTM). Significant increases in absolute as well as specific characteristic values were demonstrated by the reinforcement in a compression and bending test. It was also shown that quasi-static characteristic values under fatigue loading are maintained to a greater extent with the core reinforcement. The sandwich material was applied as a floor assembly for a snow groomer. The design was tailor-made for the mechanical, thermal and acoustic requirements. This proved the transferability of the process chain for manufacturing samples to the production of large-volume components with complex geometry.

Inorganic-organic nanocomposite networks: Structure, curing reaction, properties, and hard coating performance

This study reports the first structure and morphology details of octakis(acryloyloxypropyl)-octasilsesquioxane (POSS-Acryl8), a reactive inorganic-organic hybrid molecule, before and after photochemically crosslinked. POSS-Acryl8 was confirmed as an oblate ellipsoidal nanoparticle consisting of inorganic cage core (0.774 nm diameter) and chemically-bonded organic shell (1.447 nm thickness). The core volume fraction is only 0.95% in a single molecule, but drastically increases up to 18.8% in the neat bulk state and 31.9% in the photocured film state; the individual inorganic cores are eventually encapsulated with the networked shells (0.176 nm thickness) chemically interconnected with the neighbors. Based on such the highly networked structure and inorganic core reinforcement, the photocured POSS-Acryl8 exhibited exceptionally high optical transparency, glass transition temperature, surface hardness, and abrasion resistances. Due to the superior properties, clear hard POSS-Acryl8 coatings solved completely inherently poor surface hardness and abrasion resistances of conventional polymer window substrates and, furthermore, serious drawbacks in the eraser and steel wool abrasion resistances of glass window substrate. In addition, POSS-Acryl8 was found miscible with pentaerythritolylethyl tetraacrylate (PEEO-Acryl4) and thereby enhanced substantially the surface hardness and abrasion resistances of PEEO-Acryl4 through nanocomposite network formations. It turns out that the photocurable inorganic-organic POSS-Acryl8 hybrid and its composites with fully organic PEEO-Acryl4 are so suitable for optically clear hard top coating applications in advanced telecommunication, defense, automobile, and smart home appliance (smart and foldable phones, display devices, sensor windows, etc.).

Fabrication of customized Ti6AI4V heterogeneous scaffolds with selective laser melting: Optimization of the architecture for orthopedic implant applications

Orthopedic implants with heterogeneous porous structures were known as ideal bone osteointegration. This research introduced the selective laser melting (SLM), finite element analysis (FEA), and a hydrothermal process (HT) for manufacturing a three-level heterogeneous porous structure. The macroporous structure was designed via CAD and micropores were tuned via laser power regulation. A nano-size layer of hydroxyapatite crystals was coated by an HT process. The mechanical properties were reinforced via a core-shell structure with core reinforcement. The existence of micropores and nano-hydroxyapatite coating enhanced the in vitro proliferation of preosteoblasts and osteogenic cellular behaviors of rBMSCs. Thus, the three-level heterogeneous porous titanium implants could inspire researchers with potential clue of cyto-implant interaction mechanism, therefore building ideal orthopedic implants with accelerated osteointegration. Statement of significancePorous structures of titanium implants play an important role in bone tissue regeneration; The geometrical environment influence cell behaviour and bone tissue ingrowth in all macro-/micro-/nanoscale. In this study, a novel method to fabricate heterogeneous scaffolds and its macro-/micro-/nanoscopic structures were studied. A CAD model was used to obtain the macroscopic structure and the insufficient laser power was introduced for porous microstructure. Therefore, a layer of nano hydroxyapatite was coated via hydrothermal process. Cytoproliferation and cytodifferentiation results indicated that a integrity of regular/irregular, macro-/micro-/nanoscale porous structure had advance in recruiting stem cells and promoting differentiation. This research is beneficial to the development of bone implants with better bone regeneration ability.

PENGARUH VARIASI MUTU JAKET BETON DAN PENAMBAHAN TULANGAN LATERAL TERHADAP KAPASITAS AKSIAL KOLOM BUJUR SANGKAR

Many researches have been carried out regarding concrete jacketing, such as the addition of stirrup reinforcement and enlargement of dimensions with the quality of the concrete jacket that is equal or exceeds the quality of the core column concrete. To determine the effect of concrete jacket quality and the addition of stirrup reinforcement to the axial column capacity, in this study, the core column (K25) with 25 MPa quality and the quality of the concrete jacket varied 20 MPa, 25 MPa, 30 MPa, with the addition of stirrup reinforcement (KJs column) and without the addition of stirrup reinforcement (KJ column) in each variation of the quality of concrete jackets. It made 3 colomn for each type of treatment. The core column has a square shape with dimensions 80 x 80 x 320 mm and a concrete reinforcement jacket is given with dimensions 160 x 160 x 300 mm. The column is given concentric axial load and the shortening is calculated using a dial gauge for every 20 kN load. The results of this study indicate the addition of jacket and stirrup reinforcement concrete can increase axial capacity and column ductility. As for the increase in axial capacity that occurs in the KJ20, KJ25, KJ30 column, the K25 column is respectively 17.4%; 34.0%; 34.7%. While the axial capacity increase in the KJs20, KJs25, KJs30 columns, for the K25 column is 54.9%; 62.5%; 71.5%. The reinforcement column with the addition of stirrup reinforcement, has a shorter value and greater axial capacity than the core column and reinforcement column without accompanying the addition of stirrups. The increase in axial capacity that occurs also increases along with the increase in the concrete compressive strength of the jacket which is used as reinforcement. &#x0D; Keywords: quality variation, axial capacity, concrete jacketing.

Reductions in vancomycin and meropenem following the implementation of a febrile neutropenia management algorithm in hospitalized adults: An interrupted time series analysis.

To evaluate broad-spectrum intravenous antibiotic use before and after the implementation of a revised febrile neutropenia management algorithm in a population of adults with hematologic malignancies. Quasi-experimental study. Patients admitted between 2014 and 2018 to the Adult Malignant Hematology service of an acute-care hospital in the United States. Aggregate data for adult malignant hematology service were obtained for population-level antibiotic use: days of therapy (DOT), C. difficile infections, bacterial bloodstream infections, intensive care unit (ICU) length of stay, and in-hospital mortality. All rates are reported per 1,000 patient days before the implementation of an febrile neutropenia management algorithm (July 2014-May 2016) and after the intervention (June 2016-December 2018). These data were compared using interrupted time series analysis. In total, 2,014 patients comprised 6,788 encounters and 89,612 patient days during the study period. Broad-spectrum intravenous (IV) antibiotic use decreased by 5.7% with immediate reductions in meropenem and vancomycin use by 22 (P = .02) and 15 (P = .001) DOT per 1,000 patient days, respectively. Bacterial bloodstream infection rates significantly increased following algorithm implementation. No differences were observed in the use of other antibiotics or safety outcomes including C. difficile infection, ICU length of stay, and in-hospital mortality. Reductions in vancomycin and meropenem were observed following the implementation of a more stringent febrile neutropenia management algorithm, without evidence of adverse outcomes. Successful implementation occurred through a collaborative effort and continues to be a core reinforcement strategy at our institution. Future studies evaluating patient-level data may identify further stewardship opportunities in this population.

Core reinforcement design for improving flexural energy-absorption of corrugated sandwich composite structure

To strengthen Specific Energy-Absorption (SEA) behavior of Sandwich Composite Structure (SCS), a kind of light-weight vertical stiffener is proposed for the corrugated core. The vertical stiffener, embedded in the corrugated core, can not only absorb part of energy but also simultaneously enhance Energy-Absorption (EA) of other components. The Hashin damage model considering the shear stress and ductile damage model is adopted to predict the failure of carbon fiber face-sheets and aluminum-core, respectively. The perfect bonding is modeled for interfaces between the face-sheet and core due to little realistic debonding. The finite element model is verified by available data of conventional SCS. To obtain more design ideas, several stiffeners with different thicknesses, numbers, and positions are investigated. From the predicted results, both the flexural load and deformation of SCS correlate well with experimental results. It is highlighted that the SCSs with different vertical stiffeners exhibit 9.74%–58.48% higher SEA than the SCS without stiffener. The complex reinforcement mechanisms are extensively revealed by underlying coupling EA and deformation mechanisms. Structural parameter analysis shows that the thickness and number have significant effects on the flexural behavior and SEA of reinforced SCS.

A novel means of improving the performance of reinforced concrete beams using the welded wire mesh as core zone reinforcement

The present practice of using shear reinforcement in the form of stirrups, which go round near to the periphery in reinforced concrete beams, leaves the core zone of the cross section, where there is existence of high shear stress, un-reinforced. This leads to sudden appearance and propagation of cracks, leading to brittle failures under shear. The performance of the reinforced concrete beam will get improved if such core zone is also reinforced. This paper presents a novel means of using prefabricated mesh either as transverse reinforcement in place of conventional stirrups or as longitudinal core reinforcement apart from stirrups/ties, which not only reinforces the core zone of reinforced concrete cross section but also provide resistance against diagonal tension due to shear in continuous manner. The pilot experimental investigation conducted on RC beams provided with welded wire mesh as core zone reinforcement indicated improved performance compared to the ultimate resistance of RC beams provided with only conventional stirrups.

Highly Reactive Prestressed Aluminum under High Velocity Impact Loading: Processing for Improved Energy Conversion

Harnessing greater power from metal particle combustion requires engineering the core‐shell particle structure to more rapidly release stored chemical energy upon ignition. This study examines the metallurgical process of prestressing to increase the strain inside aluminum (Al) particles, then links increased strain to altered reaction mechanisms under high velocity impact. Results show that the quenching rate during prestressing changes the Al reaction mechanism. At faster quenching rates (900 K min−1), roughly 50% of the interfacial surface between the Al core and Al2O3 shell delaminates based on a model developed to understand the measured strain. Without core reinforcement, the shell fractures readily upon impact causing dramatically increased ignition sensitivity (measured in terms of pressurization rate) and reactivity (measured in terms of flame spreading). For slower quenching rates (200 K min−1), the core‐shell interface remains intact but strain in the particle increases by an order of magnitude. In addition, elastic stiffness in the shell may increase during prestressing. Increased elastic stiffness can effectively reduce ignition sensitivity and higher strain may contribute energy toward the nearly 40% increase in reactivity for the slower quenched aluminum powder. These results establish a link between altering mechanical properties of particles and their ignition and reactivity under dynamic loads.

Lightweight Potential of 3D Endless Fiber Reinforcement of Polyurethane Foam Cores with Spacer Fabrics in Hybrid Sandwich Structures with Fiber Reinforced Thermoplastic Facings

Sandwich structures consisting of fibre-reinforced plastic (FRP) facings and core are ideally suited as substitution materials for reducing component masses. The endless fibre reinforcement has the greatest performance potential. Both thermoset and thermoplastics are already being processed into endless fibre-reinforced sandwich facings according to the state of the art. The 3D endless fibre reinforcement of cores is a current research topic. This paper describes the development of a hybrid sandwich consisting of thermoplastic composite facings and an innovative core composite. This is made of polyurethane (PUR) rigid or flexible foam, which is reinforced with spacer fabric. The sandwich manufacturing in Reaction Injection Moulding (RIM) includes the original forming of the core and the simultaneous bonding of the facings. This efficient process offers the potential for the production of such complex structures in medium or large series. The sandwich structures and their individual components were characterised in the standardised compression and bending test. The lightweight potential of spacer fabric reinforcement is demonstrated by comparing the specific mechanical properties of sandwich structures with and without core reinforcement. In comparison to reinforced and unreinforced foams, the effect of sandwich design is also shown.

High-value, collaborative networks

Networks that generate collaboration and innovative ideas on a regular basis are characterized in this paper as high-value, collaborative networks. The initiation and development of these networks outside of the confines of a formal organization is analyzed in the context of the Engineering Project Organization Society (EPOS). The society, initiated by Professor Raymond Levitt, has existed for 15 years and continues to grow while retaining a core group of founding members. We conducted and analyzed interviews with society members to develop a framework that describes how individuals can form a core with sufficient pull to enable a network to form, stabilize and grow. The framework provides a perspective on how networks sustain through its individual members, the environment in which the network exists, and the rewards individuals obtain from being part of the network. Each of these elements by itself is insufficient to develop network stability; rather, it is the combination of a stable network core and continuous reinforcement of value from the network that serves to preserve and expand network membership. The development of the framework will benefit both academic and professional contexts by highlighting the key elements required to introduce and sustain a dynamic knowledge network.

Flexural Behavior of Composite Concrete–Epoxy–Reinforced Concrete Beams

This paper deals with the structural performance of composite reinforced concrete beams made of two different concretes, bonded together using epoxy resin. The fabricated beam section consists of low-strength reinforced concrete core and relatively large thickness outer skin concrete jacket without reinforcement. The results confirm that the bonding technique used for constructing the composite section is effective. Flexural strength of the tested beam is mainly governed by the outer jacket thickness followed by the compressive strength of concrete. A simple flexural analytical model was developed to calculate moment capacity of composite sections. The predictions were found accurate and can be utilized for the flexural analysis and design of composite reinforced concrete beams. A parametric study was made to investigate the effects of core reinforcement and both composite section geometry and material properties on the depth of compression zone and moment capacity of the section.

Paper twines in the pultrusion process – Pilot production and flexural characterization of sandwich rods

This paper describes the possibility of the use of paper twines as core reinforcement in thermoset pultruded sandwich composites. Paper twines and glass fiber rovings were co-impregnated with polyester resin and co-pultruded to form sandwich rods. Pultruded sandwich rods were up to 26% lighter with regard to typical monolithic glass fiber reinforced polyester rods. The specific flexural strength and Young's modulus of the sandwich rods were up to 25% higher than those of monolithic glass fiber/polyester commercial rods. Thanks to its light weight and its availability as a continuous twine, paper twines may be used with great flexibility in pultrusion of sandwich structures. This may lead to up to 20–30% weight reduction and cost saving without losing flexural performance.

EXTERNAL REINFORCEMENT OF CONCRETE STRUCTURES USING COMPOSITE MATERIALS

The paper describes the main directions of non-metallic composite application in concrete reinforcement. The development routes of the structural analysis with composite reinforcement are formulated. The reinforced concrete structure combines the elastic reinforcement element with an adhesive composition having inelastic properties. It is shown that the structural reliability is ensured by adhesion of composite core reinforcement to the concrete. When performing external reinforcement of composite materials, it is necessary to ensure the joint operation of reinforcing elements and the main structure. Today, design methods of concrete structure reinforcement with composite materials do not take into account shear strains in the contact seam. Adhesion of composite material to concrete is indirectly assessed by introducing the service factor of composite material when its design resistance is assigned. Experimental studies concern concrete structures reinforced by bent elements with external reinforcement made of various composite materials. Reinforced concrete beams with A500 and A600 class reinforcement are considered. Test beams are reinforced with fiberglass, coal and carbonates canvases. Some of test beams have U-shaped anchors at the ends and are made of composite materials. Reinforced beams fracture by different schemes: composite peeling due to the adhesive destruction in the area of formation of normal and inclined cracks, compositepeeling with the destruction of protective layer, composite rupture. A part of reinforced concrete beams before the reinforcement are cracked in the stretched zone. Cracks do not affect the load-bearing capacity of reinforced beams.

T147. DECREASED STRIATAL REWARD PREDICTION ERROR CODING IN UNMEDICATED SCHIZOPHRENIA PATIENTS

BackgroundReinforcement learning involves flexible adaptation towards a changing environment and is driven by dopaminergic reward prediction error (RPE; outcome (R) – expectation (Q)) signaling in the midbrain and projecting regions, such as the ventral striatum (Schultz, 1998). Schizophrenia patients show heightened dopamine levels in the striatum (Howes et al., 2012) as well as deficits in reinforcement learning (Waltz, 2016) which may be mediated by disrupted prediction error signaling (Heinz and Schlagenhauf, 2010; Schlagenhauf et al., 2014). Using model-based fMRI, the present study aims to assess these neural signals during a reversal learning paradigm in unmedicated schizophrenia patients and healthy individuals.MethodsIn the current study, 19 schizophrenia patients and 23 age- and gender-matched healthy controls completed a reversal learning paradigm (Boehme et al., 2015) during fMRI scanning where subjects had to choose between two neutral stimuli to maximize their reward. A Rescorla Wagner learning model (Single Update, one learning rate) was fitted against the individual choice data using a softmax function. Individual RPE trajectories from the fitted Rescorla Wager learning model were correlated with the BOLD response during feedback onset. Parameter estimates of ventral striaral RPE trajectories were correlated with psychopathology scores from the PANSS (Kay et al., 1987).ResultsIn the reversal learning task, schizophrenia patients chose the correct stimulus less often compared to healthy individuals (percent correct choices: 65.7 ± 10.7 vs. 76.7 ± 7.7; t=3.7, p=0.001). Across all participants, the RPE trajectories correlated with BOLD response in the bilateral ventral striatum (left ventral striatum [-10 12 10], t=7.40, pFWE <0.001, right ventral striatum [10 12 -10], t=6.56, pFWE=0.006). Schizophrenia patients displayed decreased RPE coding in the right ventral striatum compared to healthy individuals ([14 14 -10], t=3.69, pSVC for nucleus accumbens = .015). In patients, extracted parameter estimates from the right ventral striatum correlated negatively with the PANSS total symptoms score (Spearman’s rho =-0.55, p=0.018).DiscussionWe found that unmedicated schizophrenia patients performed worse in the reversal learning task and displayed decreased striatal prediction error signaling. This neural deficit was increased in patients with overall higher symptom severity. While RPE coding seems to be intact in patients receiving antipsychotic medication (Culbreth et al., 2016), our findings are in line with previous studies in unmedicated schizophrenia patients (Reinen et al., 2016; Schlagenhauf et al., 2014). Therefore, deficient neural coding of this core reinforcement learning mechanism may reflect a characteristic of the disorder of schizophrenia and does not result from antipsychotic medication.

Performance Evaluation of Exterior Beam–Column Joint with Core Reinforcement Technique Subjected to Reverse Cyclic Loading

The present work aims to study the performance of exterior beam–column joint with core reinforcement technique subjected to reverse cyclic loading. In this experimental study, three sets of one-third scaled exterior beam–column joint specimens using M30 grade concrete were cast and tested. The first set of specimens were detailed as ordinary moment resisting frame (IS:456 and SP:34) and designated as joint BCJ1. The second sets of specimens were detailed as special moment resisting frame (IS:13920) and designated as joint BCJ2. In the third set, the reinforcement detailing followed in joint BCJ1 was integrated with a new type of reinforcement (called “core reinforcement”) proposed in this study and designated as joint BCJ3. Based on the experimental result, the joint BCJ3 gave the better performance considering the strength in terms of load-carrying capacity, energy dissipation capacity, stiffness and ductility factor. The results of reverse cyclic loading tests performed in the exterior beam–column joint models indicate that the additional core reinforcement in the beam–column joint region provide adequate ductility. The stiffness of the joint with additional core reinforcement in the beam–column joint region did not undergo much reduction when compared to other types of joints. In addition, the usage of core reinforcement in the joint region can reduce its installation and difficulties in placing and compacting the concrete. This combination of core reinforcement technique in the beam–column joint region may contribute to reduction in destruction due to earthquakes.