Reinforcement Techniques Research Articles

Bimbingan Teknik Reinforcement dalam Meningkatkan Target Hafalan Santri

This article examines reinforcement techniques in memorizing the Al-Quran. Memorizing the AlQuran is a special part that cannot be separated from Islamic boarding school education. Memorizing is not an extracurricular lesson like in public schools. However, it is one of the main lessons at Islamic boarding schools. In Islamic teachings, memorizing the Al-Quran is a command from Allah SWT. The type of research used is descriptive qualitative. This research observes the implementation of guidance using reinforcement techniques carried out by teachers at the Ma'hadul Qur'an Pondok Pesantren Salafiyah Syafi'iyah Sukorejo to help deal with students' memorization problems. The research results showed that the guidance process using reinforcement techniques was successful. Guidance is carried out using behavioral therapy, then continued with reinforcement techniques. The results of this technique can make students aware that what they have been doing so far can be detrimental to themselves and these students realize that successful people are diligent people, not lazy people.

Push-Out Bond Strength of Fiber Posts to Overflared Root Canals in Different Root Regions: Effect of Reinforcement Techniques.

Objectives: This study aimed to investigate the effect of different reinforcement techniques on the push-out bond strength of fiber posts to over-flared root canals. Materials and Methods: Forty-eight extracted human single-canal premolars were endodontically treated, over-flared, and randomly divided into four groups (N=12) including SARC: luting with self-adhesive resin cement, DCC: luting with dual-cure core build-up resin composite, CRR: relining root canal walls with bulk-fill resin composite, and DAP: relining fiber post with bulk-fill resin composite. After 24 hours, the roots were sectioned to obtain three cervical, middle, and apical 3mm slices. The push-out test was performed and failure pattern was examined. Kruskal-Wallis and post-hoc Dunn-Bonferroni tests were used for statistical analysis (P<0.05). Results: In all three regions, the lowest and highest bond strength was found in the SARC and DAP groups, respectively. In the middle region, there was a statistically significant difference between the bond strength of the SARC group and that of the DCC (P=0.044), CRR (P=0.021), and DAP (P<0.001) groups. There was no significant difference in the apical region. The lowest bond strength was observed in the apical region, and the highest was related to the cervical region. Adhesive failure was the most common failure pattern in all groups. Conclusion: Based on our results DCC, CRR and DAP methods increased bond strength in the middle and cervical sections of over-flared root regions. Considering that DCC is the easiest and most practical method, we propose that CRR and DAP can be replaced with this method in clinical procedures.

Effect of calcium sources on enzyme-induced carbonate precipitation to solidify desert aeolian sand

Enzyme-induced carbonate precipitation (EICP) is a promising technique for soil reinforcement. To select a suitable calcium source and a suitable solution amount for aeolian sand stabilization using EICP, specimens treated with different solution amounts (1.5, 2, 2.5, 3, and 3.5 L/m2). Surface strength, crust thickness, calcium carbonate content (CCC) and water vapor adsorption tests were performed to evaluate the effect of two calcium sources (calcium acetate and calcium chloride) on aeolian sand solidification. The plant suitability of solidified sand was investigated by the sea buckthorn growth test. The suitable calcium source was then used for the laboratory wind tunnel test and the field test to examine the erosion resistance of solidified sand. The results demonstrated that Ca(CH3COO)2-treated specimens exhibited higher strength than CaCl2-treated specimens at the same EICP solution amount, and the water vapor equilibrium adsorption mass of Ca(CH3COO)2-treated specimens was less, indicating that Ca(CH3COO)2-solidified sand was more effective and had better long-term stability. In addition, plants grown in Ca(CH3COO)2-treated sand had greater seedling emergence percentage and higher average height, which indicated that calcium acetate is a more suitable calcium source for EICP treatment. Furthermore, the surface strength and crust thickness of solidified sand increased with increasing the solution amount. For sand treated with 3 L/m2 of solution, the excessive strength and thickness of the crust made plants growth difficult, and the performance of sand treated with more than 2 L/m2 of solution significantly improved. Thus, the solution amount of 2–3 L/m2 is suggested for engineering applications. The sand solidified using EICP in the field could effectively mitigate wind erosion and facilitate the growth of native plants. Therefore, EICP can be combined with vegetative method to achieve long-term wind erosion control in the future.

Comparative assessment of load-bearing capacities in bolted laminated bamboo lumber connections: A study on diverse reinforcement techniques

Laminated bamboo lumber (LBL), a renowned engineered bamboo composite known for its outstanding performance and sustainability, is extensively used in modern bamboo structured buildings. This study focuses on examining the effects of diverse reinforcement techniques, particularly self-tapping screws and tension control bolts, on the load-bearing capacity of bolted LBL connections with steel plates. In total, 24 specimens were categorized into 8 groups and subjected to monotonic loading tests. The test results demonstrate that the non-reinforced group clearly shows longitudinal splitting failure at the bolt position, followed by a decrease in load-bearing capacity after failure. In contrast, the group with self-tapping screws (ST) and tension control bolts (BT) exhibited fiber tearing at the lower part of the midspan, accompanied by section bending and damage. The final load-bearing capacity of the groups reinforced with single-row three-bolt self-tapping screws and tension control bolts showed an increase of 67.30 % and 52.95 %, respectively. Likewise, the groups with single-row four-bolt configurations also demonstrated significant reinforcement effects, with increases of 40.52 % and 29.66 %, respectively. Furthermore, DIC-3D analysis was employed to examine the displacement of the connection bolts, and the van der Put model was utilized to estimate the load-bearing capacity of bolted LBL connections under splitting conditions. Subsequently, finite element models were established and calibrated based on the experimental data. The results confirm that self-tapping screws and tension control bolts can serve as structural enhancements in the design of bolted LBL connections, providing effective reinforcement for existing engineering structures.

Acoustic emission responses and damage estimation of coal with carbon fiber-reinforced polymer confinement under uniaxial compression

Fiber-reinforced polymer (FRP) wrapping is a potential technique for coal pillar reinforcement. In this study, an acoustic emission (AE) technique was employed to monitor coal specimens with carbon FRP (CFRP) jackets during uniaxial compression, which addressed the inability to observe the cracks inside the FRP-reinforced coal pillars by conventional field inspection techniques. The spatiotemporal fractal evolution of the cumulated AE events during loading was investigated based on fractal theory. The results indicated that the AE response and fractal features of the coal specimens were closely related to their damage evolution, with CFRP exerting a significant influence. In particular, during the unstable crack development stage, the evolutionary patterns of the AE count and energy curves of the CFRP-confined specimens underwent a transformation from the slight shock–major shock type to the slight shock–sub-major shock–slight shock–major shock type, in contrast to the unconfined coal specimens. The AE b-values decreased to a minimum and then increased marginally. The AE spatial fractal dimension increased rapidly, whereas the AE temporal fractal dimension fluctuated significantly during the accumulation and release of strain energy. Ultimately, based on the AE count and AE energy evolution, a damage factor was proposed for the coal samples with CFRP jackets. Furthermore, a damage constitutive model was established, considering the CFRP jacket and the compaction characteristics of the coal. This model provides an effective description of the stress–strain relationship of coal specimens with CFRP jackets.

Experimental investigation of External FRP strengthening column against secondary moment of slender effect

The essential design code guidelines for Fiber Reinforced Polymer (FRP) strengthened Reinforced concrete columns are limited to short columns strengthened with FRP wrapping. As a result, they are primarily non-applicable to slender RC columns where there is a significant second-order/slenderness impact. The purpose of the current study was to experimentally recognize how effectively longitudinal carbon panels (CFRP) and basalt fiber-reinforced polymer (BFRP) lateral wrapping can reduce lateral deflection and increase the strength of variable thin square reinforced concrete columns. A total of 8 square RC columns of 120 mm width were performed in three groups, according to the slenderness ratio 22, 29, and 35. The strengthened columns were developed using two distinct strengthening techniques. The first is a longitudinal CFRP laminate with lateral partial BFRP wrapping (EBWGL) plus grooved bonding, and the second is a lateral partial wrapping (EBW) of the BFRP film. The column was tested with 30 mm eccentric compression. In general, the EBWGL reinforcement technique significantly improves the flexural strength of columns. Moreover, it is noteworthy that the EBW method did not considerably reduce the secondary effect as the slenderness ratio increased. The EBGWL has a great reducing effect that gets better as the slenderness ratio gets higher.

A Positive Start: Backing a Horse Using Positive Reinforcement

Abstract This case study delves into the transformative approach of starting a horse under saddle using a positive reinforcement technique (clicker training). Grounded in the ethos of respect, trust, and cooperation, this methodology emphasises fostering a strong bond and effective communication between horse and handler. The presented case study aims to showcase practical demonstrations highlighting the theory and application of positive reinforcement in initiating the riding training of a young pony. Throughout this case study, we will explore the foundational principles of positive reinforcement in horse training, emphasising empathy and a holistic understanding of the horse’s perspective. It will detail the step-by-step process of introducing the saddle, bridle, and mounting, employing clicker training and shaping techniques. Practical demonstrations will illustrate the gradual introduction of equipment, the use of clicker training for reinforcing desired behaviours, and the shaping of responses to riding cues. Through these demonstrations, the case study seeks to exemplify how positive reinforcement techniques can establish a willing and confident young horse, laying the groundwork for a harmonious and trusting relationship between horse and rider. Information © The Author 2024

Optimization of pre-grouting construction and evaluation of grouting effect in a deeply buried silt-filled shield tunnel

Controlling strata deformation during shield tunneling beneath unconsolidated soil layers poses a significant challenge in engineering construction. Limited research exists on optimizing pre-grouting mechanisms for shield tunnels in unconsolidated soil layers and controlling strata deformation. Therefore, conducting on-site optimization experiments for pre-grouting is crucial for controlling strata deformation. The paper employs crushed stone aggregate as a basis for modifying the shield jacket material. The primary method of verifying grout strength involves direct detection of foundation bearing capacity using a heavy-duty probe inside the tunnel. The feasibility of the comprehensive evaluation scheme is further confirmed through a combination of multi-point core sampling, five-point water pressure tests, and on-site shield monitoring data. The research results indicate that this technology effectively enhances the stability of deep-buried weak strata. By improving the physical and mechanical properties of backfill soil through a combination of crushed stone-cement slurry-soil skeleton, the self-stabilizing ability of surrounding rock is enhanced, and strata deformation is controlled. Additionally, a set of pre-grouting reinforcement and evaluation techniques suitable for deep-buried weak strata is proposed, providing valuable references for similar projects.

Impact of early socialisation in foster care on kitten behaviour

ObjectivesThe critical socialisation period for kittens is estimated to be 2–7 weeks of age. Kittens reared in shelters often have poorer outcomes due to high rates of infectious disease. Therefore, many shelters are reliant on foster care programs to improve kitten survival rates and behaviour. However, little is known about the impact of specific early socialisation factors on kitten behaviour and health. MethodsDuring a 23-month period, 598 kitten foster carers completed a kitten socialisation questionnaire. The relationships between kitten weight/age at intake, days in care, singleton status, and the presence or absence of the queen during care on kitten behaviour and disease incidence were explored. Associations with exposure to noise, adults, children, location where the kitten was kept in the home, time spent alone, and ringworm treatment were also investigated. ResultsOverall being kept in social areas of the house with less noise/activity and spending some time alone was associated with positive kitten behaviour. There was no difference in fear or anxiety responses for bottle fed kittens, singletons and those without the queen. Ringworm treatment was associated with more fearful behaviour in kittens. Conclusionsand relevance: Future foster carers should be encouraged to keep kittens in social areas of the house, whilst also ensuring kittens can spend some time alone. If the home is loud, carers should slowly introduce the kitten/s to the louder and busier areas of the house before being housed there all the time. Training of carers to use more positive reinforcement techniques for administering ringworm treatment may benefit kitten behaviour.

Monitoring of early curing stage of cemented soil using polymer optical fiber sensors and microscopic observation

Deep cement mixing (DCM) piles are widely utilized for reinforcing soft clay foundations, particularly in coastal regions where soil stability is critical. Monitoring the quality and early-stage behavior of cemented soil is essential to ensure the effectiveness of DCM pile projects in meeting design requirements. Innovative methods for on-site monitoring are necessary to enhance the reliability and efficiency of these reinforcement techniques. In this study, a novel approach is proposed utilizing polymer optical fiber (POF) sensors based on physical optical sensing principles to monitor the initial hydration degree and overall quality of cemented soil during the early curing stage. The proposed method relies on the principle of physical optical sensing, where POF sensors are employed to measure changes in reflected light intensity (LI) and temperature in cemented soil. Two crucial variables, namely the initial water content and the amount of cement, are considered in analyzing their impact on the LI and temperature changes over time. Unconfined compressive strength (UCS) tests and scanning electron microscopy (SEM) analysis are conducted on cemented soil samples with varying water-cement ratios to investigate their mechanical properties and microstructure evolution. The results of the UCS tests indicate that higher initial water content prolongs the initial hydration reaction time required for cemented soil with different cement contents. Analysis of LI curves reveals a rapidly rising trend as the hydration reaction progresses, particularly evident in samples with higher initial water content. SEM analysis further demonstrates that a stable POF LI corresponds to the completion of the hydration process, with hydrated gel formation resulting in a more compact microstructure and smaller voids. The findings highlight the significant influence of cement quantity and initial water content on the mechanical strength and microstructure of cemented soil. By analyzing changes in reflected LI and temperature, the proposed monitoring method provides valuable insights into the early-stage behavior and quality of cemented soil during the curing process. This innovative use of POF sensors for on-site monitoring offers a novel approach to evaluating cemented soil in DCM pile projects.

Ex Vivo Biomechanical Bone Testing of Pig Femur as an Experimental Model.

This study investigates the mechanical behavior of femur bones under loading conditions, focusing on the transition from elastic to plastic deformation and eventual fracture. The force-displacement curves reveal distinct phases of deformation, with an initial linear relationship indicating elastic behavior, followed by deviation from linearity marking the onset of plastic deformation. Fracture occurs beyond a critical load, leading to a sharp drop in the force-displacement curve. The maximum fracture force varies among specimens and is influenced by bone geometry, size, cross-sectional area, and cortical thickness. Post-failure analysis highlights additional insights into fracture mechanics and bone material toughness. Reinforcing bones with screws enhances their strength, which is evident in the higher fracture forces observed in force-displacement diagrams. Fixation procedures following fractures further increase bone strength. Comparing specimens with and without strengthening underscores the effectiveness of reinforcement methods in improving bone mechanical properties. After analyzing the results, it is evident that femur bones with reinforcement can withstand greater loads, and they can also absorb higher impact energies while remaining in the elastic deformation range and without suffering permanent plastic damage. This study provides valuable insights into bone biomechanics and the efficacy of reinforcement techniques in enhancing bone strength and fracture resistance.

Behavioral training and mirroring techniques to prepare for elective anesthesia in children with autism spectrum disorder: a prospective evaluation of implemented program.

Children with autism spectrum disorder (ASD) often require multiple interventions receiving general anesthesia during their lifetimes. However, a single negative experience may trigger and/or aggravate anxiety and subsequent development of unwanted behavior. This monocentric study assessed the compliance with mask induction of children with ASD who followed a preoperative preparation using behavioral training with positive reinforcement technique and use of mirroring technique. Prospective observational study including all children with ASD scheduled for day case treatment receiving general anesthesia, from November 2019 to August 2022. The primary outcome was Induction Compliance Checklist (ICC) score. The secondary outcomes were child's anxiety in the operating room assessed by the modified Yale Anxiety Scale (mYPAS), the comportment of the child in the recovery room, parental satisfaction about perioperative management (0 to 10 numerical scale) and the satisfaction of the caregivers about anesthetic management (0 to 10 numerical scale). Behavioral changes were assessed one month after the procedure when possible. In total, 43 children from one to 17 years old were included. Median ICC score was 3 [1-6]. Induction Compliance was considered as excellent in 18.6% of patients, good in 39.5%, fair in 14.0% and poor in 27.9%. Seven patients (16.3%) needed restraint during induction. The use of behavioral and mirroring techniques implemented as a preparation program for children with ASD could facilitate mask induction of anesthesia. Such a preparation achieves good to excellent compliance in almost 60% of patients.

STABILITY ASSESSMENT OF ROOT-REINFORCED SLOPES USING FINITE ELEMENT LIMIT ANALYSIS

Slope instability poses serious threats to infrastructure and environmental sustainability. As a result, numerous reinforcement techniques have been used as disaster mitigation attempts to prevent slope failure. Among various traditional slope reinforcement methods, the use of vegetion root is more cost-effective and environmentally friendly. This paper presents stability assessment of root-reinforced slopes. Firstly, slope models were built for case of bare and root-reinforced slopes. The slope angles were varied in the range of 15º ~ 55 º. The root cohesion and depth of root zone were adjusted within the ranges of 0 ~ 20 kPa and 0 ~1.5 m, respectively. The strength reduction finite element limit analysis method was applied to evaluate the stability of the slopes in this study. The results indicate that factor of safety increases with the increasing of root cohesion and depth of root zone. The best factor of safety was obtained for the case with root cohesion and depth of root zone of 20 kPa and 1.5 m, respectively. Shear dissipation contours of the slope models also show that root reinforcement reduces shear dissipation energy along the failure surface, consequently lowering the possibility of slope failure.

Pressure resistance characterisation of vascular networks embedded in carbon composites for high energy physics applications

In state-of-the-art tracking detectors, lightweight carbon composite structures support the pixel or micro-strip sensors and provide the main thermal path between the silicon and a network of metallic or plastic pipes containing a cooling fluid. Despite the good results obtained with this design approach, the challenges associated with future high energy physics (HEP) experiments demand even lighter and more efficient technologies. In this regard, replacing the existing piping with a network of channels directly embedded in the composite laminates represents a promising solution to improve the thermal coupling, which also offers additional gains in terms of mass and thermo-elastic stability.While some research has been devoted to assessing the mechanical and thermal performance of such laminates, limited information about their resistance to internal pressure is currently available in the literature. This lack of data constitutes an important obstacle for the use of vascular networks in future HEP applications, which the present paper aims to address.Experimental methods were used to investigate the pressure resistance of channels embedded in carbon composite laminates. Modified poly (lactic) acid (PLA) preforms were embedded in carbon-fibre epoxy laminates. A post-cure vaporization technique removed the PLA, thus producing plates with longitudinal channels. Destructive tests were conducted to determine the burst pressure of the plates depending on the lay-up and the cross-section geometry of the channels. Both circular and oblong channels were evaluated, and various reinforcement techniques were explored to enhance the pressure resistance of the laminates. Micro-graphic examinations and X-ray micro-computed tomography were employed to gain a better understanding of the microstructure and the failure mechanisms of the plates.Plates with circular channels measuring 1.75 mm in diameter, embedded in [0/90/0]S laminates and reinforced with 2 mm lay length fuzzy carbon fibre over-braids, achieved burst pressures exceeding 45 MPa. This result, which is approximately an order of magnitude greater than that obtained for the equivalent non-reinforced laminates, demonstrates the enormous potential of this technology for future particle detectors.

PENERAPAN KONSELING RATIONAL EMOTIVE THERAPY DENGAN TEKNIK REINFORCEMENT UNTUK MENGOPTIMALKAN MOTIVASI BELAJAR DI PONDOK PESANTREN AN-NUUR

This research originates from the problems of students at the An-nuur Islamic boarding school who experience a decrease in learning motivation. Decreased motivation to learn originates from irrational thinking, resulting in irrational behavior. Learning motivation is the urge or desire to do something to achieve a goal. To help with these students' problems, researchers provide counseling services using a rational emotive therapy approach using reinforcement techniques. The goal of rational emotive therapy counseling is to help clients free themselves from illogical ways of thinking or ideas and replace them with logical ways of thinking. Providing reinforcement techniques aims to provide reinforcement in all decisions and changes made by the counselee. This strengthening is expected to help the counselee in making changes.

Teknik Reinforcement dalam Menurunkan Perilaku Agresif pada Anak Usia Dini

The purpose of this study is to reduce aggressiveness in early childhood, especially 5-6 years of age. This research is a quasi-experiment research with Nonequivalent control group design, data collection techniques using observation and documentation. The population in this study were 2 classes, namely group B1 and group B2 with random sampling technique, each of which had 15 students. Data collection techniques using observation and documentation. The instrument measurement scale uses a Likert scale. The data analysis technique uses the t test, namely independent sample t-test and paired sampe-test to determine the comparison when the pretest and postest. The data was processed using the help of SPPS for windows to determine whether the hypothesis was rejected or accepted. The results showed that after treatment for 5 times, it can be seen from the results of calculations with SPSS which obtained a value of 0.000 which means the sig value &lt;0.05. This means that there is an effect of reinforcement techniques in reducing the level of aggressiveness of Ramadani natural school children. Forms of aggressiveness in children such as pushing, grabbing, ignoring teacher calls, hitting.

Fortifying Slab Resilience against Touch-Off Explosions: Integration of Innovative Stud Reinforcements and Computational Analysis

Explosions, once limited to military and accidental contexts, now occur frequently due to advances in warfare, local disputes, and global conflicts. Recent incidents, like urban bombings, emphasize the urgent need for infrastructure to withstand explosions. Slabs, critical in architectural frameworks, are vulnerable to explosive forces due to their slimness, making them prime targets for sabotage. Scholars have explored various strategies to fortify slabs, including the use of advanced materials like CFRP laminates/strips, steel sheets and ultra-high-strength concrete, along with reinforcement techniques such as two-mesh and diagonal reinforcements. A novel approach introduced in current research involves integrating vertical short bars, or studs, to enhance slab resilience against touch-off explosions. The aim of this research endeavor is to assess the impact of studs and their utilization in bolstering the anti-contact-blast capabilities of a concrete slab. To achieve this goal, a specialized framework within the ABAQUS/Explicit 2020 software is employed for comprehensive analysis. Initially, a conventionally reinforced slab devoid of studs serves as the benchmark model for numerical validation, facilitating a comparative assessment of its anti-contact-blast effectiveness against the findings outlined by Zhao and colleagues in 2019. Following successful validation, six additional distinct slab models are formulated utilizing sophisticated software, incorporating studs of varying heights, namely, 15 mm and 10 mm. Each configuration encompasses three distinct welding scenarios: (i) integration with upper-layer bars, (ii) attachment to bottom-layer bars, and (iii) connection to both upper- and bottom-layer bars. The comparative merits of the slabs are evaluated and deliberated upon through the examination of diverse response parameters. The research revealed that the incorporation of studs within slabs yielded notable enhancements in blast resistance. Specifically, taller studs demonstrated exceptional resilience against deformation, cracking, and perforation, while also diminishing plastic damage energy. Particularly noteworthy was the superior performance observed in slabs with studs welded to both upper and lower layers of re-bars. This highlights the critical significance of both the integration of studs and their precise positioning in fortifying structural integrity against blast-induced loadings.

Localized heat treatment and XFEM-based investigation of damage mechanisms in reinforced notched plates under uniaxial tensile stress

This study delves into mechanical engineering by investigating damage mechanisms and reinforcement strategies in notched structures. Our research centers on enhancing structural integrity through a localized heat treatment technique applied at the notch before uniaxial tensile stress testing. Central to our approach is Functionally Graded Material (FGM), defined by volume fractions that specific exponents modulate. The innovation lies in treating the interface between the base metal and the heat-affected zone (HAZ). We introduce a novel meshing-based grading technique that facilitates elastoplastic behavior and allows for the gradation of damage properties. This technique is particularly noteworthy as it obviates the need for complex subroutines or FORTRAN compilation. Our methodology employs a mesh model with independent elements, each characterized by a volume fraction gradient to accurately represent the graded material’s behavior. The behavioral model is anchored in the Von Mises equivalent stress flow theory, and tensile tests inform the material properties of steel and the HAZ. The results of our investigation are presented through force-displacement curves, which critically evaluate our reinforcement technique. Moreover, using the eXtended Finite Element Method (XFEM) in our meshing approach has proven particularly effective in delineating structural behavior post-fissure initiation, showcasing its superiority in capturing the nuances of crack propagation and structural separation.

Flexural performance of concrete reinforced with ultra-high ductility magnesium phosphate cement-based composites and CFRP

With the aim to develop and assess an effective reinforcement technique for concrete beams, the approach of the combination of ultra-high ductility magnesium phosphate cement-based composites (UHDMC) and carbon fiber reinforced polymer (CFRP) was analyzed and established based on the measured parameters, including failure mode, load-deflection curve and feature points. The results showed that, for specimens reinforced by UHDMC alone or the combination of UHDMC and CFRP, several cracks in the concrete layer and multi-cracks in the UHDMC layer were both shown, presenting a ductile failure and three distinct stages in the load-deflection curve. Moreover, compared with the specimens reinforced by CFRP alone and UHDMC alone, the ultimate load and ultimate deflection both were improved in the specimens reinforced by UHDMC and CFRP. Furthermore, the strain distribution of CFRP was symmetrical along both sides of the test specimen, presenting a general law of large in the middle and small in the two ends, and its more and more obvious phenomenon with the increase of the number of CFRP layer. To some extent, the inclination trend of the overall strain of CFRP can be used to determine the location of the weak surface.

1 g shake table study on seismic strengthening of low-cost rammed earthen houses built of silt enriched soil using natural fiber reinforcement

Earthen houses are practiced as a traditional and low-cost housing in many countries around the globe. These houses were exposed to unacceptable earthquake (EQ) risks despite their environmental benefits. Past earthquakes including the recent past 2017 Tripura EQ has evidenced significant damages mostly in earthen/masonry houses which are built in a non-engineered manner. In this context, the current study aims to investigate the seismic behavior and failure patterns of both unreinforced and using proposed retrofitted rammed earth model houses (with and without openings) built using typical Tripura soils having higher silt content using unidirectional shake table experiments on total 26 physical models. Besides, both seismic strength and structural stability are also examined for retrofitted earthen houses. The study indicates that, proposed novel low-cost natural fiber made textile encasing reinforcement technique has exhibited promising seismic performance of such houses from the view point of structural strength and ductile behavior as compared to traditional cementitious additives and fiber blended stabilized retrofitted houses as well untreated houses. The fundamental lateral period of model unreinforced and reinforced houses found within the range of 0.08 to 0.15 s respectively which indicates increased stiffness of walls due to strengthening may decrease the lateral period maximum up to 46.67%. On the other hand, the maximum increase in seismic strength was observed in order of 4.50 to 6.31 times in the case of bitumen treated bamboo fiber textile based encased houses with L-shaped bamboo splint corner reinforcement whereas traditional cementitious stabilized method has offered maximum 1.13 to 1.83 times increment in lateral strength. Further, the effect of different parametric variations such as area of openings (doors and windows), thickness to height ratio, variation in compaction methodologies on seismic performances of unreinforced rammed earthen houses were also studied in detail. Finally, regression based closed form predictive expressions for seismic strength of rammed earthen houses and without retrofitting are proposed herein. The performed cost analysis study will also help to assess the effectiveness of proposed strengthening techniques.