Deformation Of Columns Research Articles

Correlation Between Hand Length And Stature

Objective: The main objective is to know the correlation between hand length and height so that a regression equation could be obtained to use for personal identification. Method: A correlational study conducted at Sialkot medical college between April, 2022 to June, 2022. Only female students of Sialkot medical college were selected by non-probability purposive sampling technique. Sample size was 141. Those having any deformity of vertebral column and hand deformity were not selected. After taking informed consent measurements were taken. Stadiometer was used to measure the height and vernier caliber was used to measure hand length. The measurements were taken in inches. Descriptive data was calculated by using SPSS 25. Correlation was found and regression equation was obtained. Regression curve was also obtained. Graphs and table were formed. Results: Value of pearson coefficient between right hand length and height was 0.780 and between left hand length and height was 0.752. Conclusion: Hand length can be used to estimate height of the person helping to short list the persons to be identified.

Simulation Calculation of the Support Column Deformation of the Precision Crane Based on Abaqus

The support columns of cranes can undergo minor deformations under heavy pressure, which poses a challenge to lifting sophisticated equipment, such as satellites. To improve the stability and accuracy of the crane, the small deformation of the support column was studied. Two methods, numerical simulation and calculus derivation, were adopted by the research team. The results show that the numerical value calculated by the finite element method is 12.43 μm, while the numerical value derived by integration is 12.50 μm. The relative error is within the acceptable range, which verifies the accuracy of the model. The finite element method can calculate the deformation of precision crane column to improve its accuracy and safety, and provide data support for the design and optimization of precision crane.

厚肉溶接箱形断面部材を用いた異幅角形鋼管柱端接合部の面外曲げ剛性

In this paper, out-of-plane bending stiffness of column-end connection between square hollow section column and thick panel with different width was investigated by loading test and finite element analysis. From the results, column-end connection of corner-type under 45-degree directional force has the smallest stiffness, and of which section dose not remain plane, and proportion of bending resistance caused by partial deformation of column in column-end bending resistance is very small. Therefore, method to estimate out-of-plane bending stiffness of column-end was proposed based on deformation of diaphragm of hollow section of panel and directly above panel.

Non-linear modeling parameters for new construction RC columns

Modeling parameters (MP) of reinforced concrete columns are a critical component of performance-based seismic assessment methodologies because in these approaches damage is estimated based on element deformations calculated using non-linear models. To ensure model fidelity and consistency of assessment results, performance-based seismic assessment methods in ASCE 41, ACI 369.1, and ACI 374.3R prescribe modeling parameters calibrated using experimental data. This paper introduces a new set of equations to calculate reinforced concrete column non-linear modeling parameters optimized for design verification of new buildings using response history analysis. Unlike modeling parameters provided in ACI 369.1 and ASCE 41, intended for columns of older non-ductile buildings, the equations for modeling parameters anl and bnl presented in this study were calibrated to simulate the load-deformation envelope of reinforced concrete columns that meet the detailing requirements of modern seismic design codes. Specifically, the proposed equations are intended for use with provisions in ACI 374.3R, Chapter 18 and Appendix A of ACI 318-19 and Chapter 16 of ASCE/SEI 7-16. The proposed equations were calibrated using the ACI Committee 369 column database, which includes column configuration parameters, material properties, and deformation capacity modeling parameters inferred from the measured response of columns under load reversals. Dimension reduction techniques were applied to visualize different clusters of data in 2D space using the negative log-likelihood score. This technique allowed decreasing the non-linearity of the problem by identifying a subset of columns with load-deformation behavior representative of new construction conforming to current codes requirements. A Neural Network model (NN) was calibrated and used to perform parametric variations to identify the most relevant input parameters and characterize their effect on modeling parameters, and to stablish the degree of non-linearity between each input variable and the model output. Developing equations for modeling parameters applicable to a wide range of columns is challenging, so this research considered subsets of the database representative of new construction columns to calibrate simple practical equations. Linear regression models including the most relevant features from the parametric study were calibrated for rectangular and circular columns. The proposed linear regression equations were found to provide better estimates of new construction column modeling parameters than the available tables in ACI 374.3R and ASCE 41-13, and the equations ASCE 41-17.

Real-time implication of hybrid carbonaceous fibre and powder integrated self-sensing cement composite in health monitoring of beams and columns

This research aspires to develop a self-sensing cement composite (SSC) utilising hybrid carbon fibre-graphite powder and carbon fibre-activated charcoal for structural health monitoring (SHM). The research assessed the electromechanical properties of SSC, including its compressive strength, resistivity, piezoresistivity, and stress sensitivity. The variance in properties of SSC fabricated using hybrid conductive materials is explored in detail through scanning electron microscopy (SEM) investigations. As per the theory of mechanics, the developed SSC is positioned in the critical zones (bending compression, bending tension, and combined flexural-shear) of the beam and column to detect their deflections. SSC with carbon fibre-graphite powder increases the compressive strength to 28.34 MPa, while the SSC with carbon fibre-activated charcoal substantially reduces SSC electrical resistivity to 6646 Ωcm. The SSC made of carbon fibre-graphite powder embedded in the tensile zone correlates with the beam deflection by 99.79%. SSC with carbon fibre-activated charcoal has 97.62% efficiency in detecting column deformation. Thus, the suggested SSC with hybrid fibre and powdered conductive materials increases electromechanical properties and has significant potential for the health monitoring of structural components.

Behavior and modeling of large-scale concrete-filled FRP tubes with longitudinal steel rebars under lateral impact loading

Fiber-reinforced polymer (FRP) has been utilized extensively as a confining material for concrete in civil engineering. Concrete-filled FRP tubes (CFFTs), consisting of a FRP tube, a concrete core and optional longitudinal rebars, are particularly attractive to be used as bridge piers in harsh environments. Most studies on CFFTs have been focused on their behaviors under static loading conditions. To extend existing studies, three identical large-scale CFFTs with longitudinal steel rebars (SR-CFFTs) were investigated experimentally, two of which were tested under lateral impact loading and one was under lateral static loading. To compare the confining behavior between FRP tube and steel stirrups, three identical large-scale reinforced concrete (RC) columns with approximately the same hoop confinement stiffness as SR-CFFTs (i.e., steel stirrups for RC columns, FRP tube for SR-CFFTs) were tested as companion specimens. The test results indicated that, (1) under lateral static loading, the RC column failed with a shear-failure manner, while the SR-CFFT specimen failed with combined bending and shear failure characteristics; (2) under lateral impact loading, the shear-dominant failure mechanism was evident for RC columns, while the failure mechanism of SR-CFFTs was flexural-dominant owing to the effective hoop confinement provided by FRP; (3) under the same impacting velocity, the SR-CFFT specimen had much less damage and much less lateral displacement than the corresponding RC column. The established FE models could provide reasonably accurate predictions for the dynamic behaviors, the impact force–time history curves and the column deformations for both RC columns and SR-CFFTs. Parameter studies were conducted to analyze the effects of the concrete strength, the longitudinal steel ratio, the impact velocity and the impact mass.

Mechanical behaviour of H-shaped steel columns reinforced with bonded steel plates and anchor bolts

A novel technique was developed for reinforcing H-shaped steel columns with bonded steel plates and bolts (BSPBs) without welding. Static tests were performed on seven full-scale reinforced columns and two full-scale unreinforced columns. The failure characteristics, strain, and displacement of the nine full-scale specimens were experimentally obtained under a static compressive load. The BSPB-reinforced H-shaped steel columns mainly failed because of local yielding and peeling of the steel plates. The reinforced specimens did not exhibit substantial instability, and the column deformation was effectively controlled. The reinforcements clearly increased the bearing capacity and stiffness of the specimens, and the anchoring bolts for symmetrically bonding the steel plates to the flange of the H-shaped steel columns without welding increased the axial bearing capacity. The influences of the steel plate thickness, anchor bolt spacing, and eccentricity on the reinforcement performance were investigated. A cohesive zone model (CZM) was used to determine the interfacial stress distribution in the adhesive layer. The corresponding theoretical predictions of the compression bearing capacity agreed well with the experimental results.

Modal analysis and harmonic response analysis of energy-absorbing and anti-scouring columns

Many field observations have found that damage to the support did not increase with the magnitude of the impact ground pressure. To enhance the impact protection performance of “support and surrounding rock” system. From the perspective of preventing the resonance of the “support and surrounding rock” system, the dynamic response of energy-absorbing and anti-scouring column is studied. Using the block theory, a dynamic model of the roadway enclosure-absorbing anti-scouring column under impact loading was established, and the dynamic response equation of the rock block at the support end was obtained. Based on the structural dynamics and Love shell theory, the characteristic equations of the energy-absorbing and anti-scouring column were derived, and the theoretical equations for the natural frequency and vibration mode function of the energy-absorbing and anti-scouring column were obtained. The ABAQUS numerical simulation method was used to carry out pre-stress modal analysis and harmonious response analysis of energy-absorbing and anti-scouring columns and conventional columns. We obtained the natural frequencies and vibration modes of the two columns and analyzed the effect of the setting load on the modalities of the columns. The column dynamic response law was determined by monitoring the displacement and velocity response curves at different positions. The results show that the natural frequency and vibration mode of the energy-absorbing and anti-scouring column are related to the density, elastic modulus, and length. The vibration of the energy-absorbing and anti-scouring column has two forms: beam vibration mode and cylindrical shell vibration mode, and the first four orders of vibration mode are transverse bend. The setting load has a small effect on the natural frequency and vibration mode of both types of columns, where the natural frequency decreases as the setting load increases. When the excitation frequency is close to the vibration frequency of the surrounding rock, the radial, axial, and circumferential response amplitudes of the primary and secondary columns of the energy-absorbing and anti-scouring column are the largest. Reinforcement and strengthening measures should be implemented to reduce the column deformation amplitude.

Evaluation of first ray instability using the double dorsiflexion test: A prospective observational case-controlled study

BackgroundFirst-Ray (FR) stability allows for foot propulsion in-stance, taking 60% weight. First-ray instability (FRI) is associated with middle column overload, synovitis, deformity and osteoarthritis. Clinical detection can still be challenging. We propose to develop a clinical test that helps identify FRI using two simple manual manoeuvres. Methods10 patients with unilateral FRI were recruited. Unaffected contralateral feet were used as controls. Stringent exclusion criteria were applied including hallux MTP pain, laxity, inflammatory arthropathy and collagen disorders. A Klauemeter directly measured the sagittal plane dorsal first metatarsal head translation of affected vs unaffected feet. Maximum passive proximal phalanx 1st MTP joint dorsiflexion was measured using a video capture and Tracker motion software analysis with and without applying a dorsal force at the 1st metatarsal head using a Newton meter. Proximal phalanx motion was compared in affected vs unaffected feet with and without dorsal metatarsal head force application and compared to direct measurements using the Klaumeter. P value of < 0.05 was considered significant. ResultsFRI feet had dorsal translation greater than 8 mm (median, 11.94; interquartile range [IQR], 10.23–13.81) vs 1.77 for unaffected control feet was (median, 1.77; interquartile range [IQR], 1.23–2.96) using the Klauemeter. The percentage reduction in 1st MTP joint dorsiflexion ROM when applying the double dorsiflexion test FRI (mean reduction of 67.98%) when compared to control feet (mean reduction of 28.44%)(P < 0.01). Receiver operating characteristic (ROC) analysis showed that a 50% reduction in dorsiflexion ROM of 1st MTPJ when performing the double dorsiflexion test achieved a specificity of 100% and sensitivity of 90% (AUC =0.990, 95%CI [0.958–1.000], P > 0.0001). ConclusionThe double dorsiflexion (DDF) is easy to perform with two relatively simple manual manoeuvres that avoids the need for complex instrumented and radiation-based assessment. Greater than 50% decrease in proximal phalanx motion has an over 90% sensitivity in identifying feet with FRI. Level of EvidenceThis was a prospective case-controlled study of consecutive cases of a level II evidence.

An analytical solution for consolidation of soils with stone columns and vertical drains by considering the deformation of stone columns

The composite foundation reinforced by stone columns and vertical drains is widely used in various projects. However, available calculation methods for such consolidation are rarely reported in the literature. Firstly, a set of basic equations are proposed to describe the seepage relations among stone columns, vertical drains, and soft soils in this study. Then, the governing consolidation equation, in which the average total excess pore water pressure (EPWP) serves as a variable, is derived by considering the deformation of stone columns during consolidation under the assumption of equal strain conditions. Moreover, the analytical solution for the consolidation equation is obtained by the method of separation of variables, and its reliability is verified by degenerating into the solution for the consolidation of composite foundations reinforced by stone columns and comparing it with the field measurements. Finally, a parametric study is performed to investigate the consolidation behavior. The results show that the consolidation rate can be significantly increased by installing vertical drains between the stone columns compared to reducing the column spacing; for some composite foundations reinforced by stone columns with a high ratio of replacement, the deformation of columns during consolidation cannot be ignored; the smear effect caused by vertical drains can be ignored in such composite foundations.

Comparative study on the seismic performance of subway stations using reinforced concrete cast-in-place columns and truncated columns

Insufficient lateral deformability of columns within the high axial force is the main failure mechanism of subway stations under earthquake loading. This study proposed applying reinforced concrete truncated (RCT) columns to improve the seismic capacity of subway stations. The seismic tests of RCT columns and cast-in-place (CIP) columns were conducted first. Then the seismic capacity of subway stations with RCT and CIP columns was discussed by push-over analysis. After that, the seismic response of subway stations with RCT and CIP columns was simulated by considering both horizontal and vertical ground motions. Numerical results presented that the vertical performance of both structures had no obvious difference. However, the earthquake-induced horizontal deformation of the structure with RCT columns was smaller than that of the structure with CIP columns, then the structure with RCT columns experienced lighter damage. Therefore, RCT columns can be applied to improve the seismic performance of subway stations.

Performance evaluation of graphite-integrated smart-engineered cementitious composite for health monitoring of structural components

This research explores the electro-mechanical characteristics of graphite powder (GP) integrated Self-Sensing Cement Composite (SCC). In addition to the development, the created SCC is used in beams and columns to evaluate their structural performance under flexural and compressive load, respectively. Field Element Scanning electron microscopy (FESEM) analysis is conducted to examine the morphological characteristics of the optimized SCC. X-Ray diffraction (XRD) analysis is used to examine the formation of chemical constituents responsible for the property variation. The research findings indicate that the resistivity of composites containing 25% GP is lowered by 43.90%. Due to the hydrophilicity between GP and cement, the strength of SCC is lowered as the concentration of GP increases. The SCC embedded in the flexural zone of beams has the capacity to detect deformation with an accuracy of 98%. The electrical resistivity of SCC in columns rapidly decreases with increasing deflection as a result of SCC compression, indicating that SCC can monitor column deformation with an efficiency of about 96% up until the elastic regime. After characterization, strength, and resistivity evaluations, GP is finally validated as a promising material for SCC development and application in structural health monitoring.

EVALUATION OF ULTIMATE DEFORMATION AND MEMBER RANK OF COLUMNS WITH SIDEWALLS

Firstly evaluating equation of ultimate deformation for reinforced concrete columns with side walls is proposed in the case that the side wall is subjected to compressive axial force. The feasibility of the proposed equation is examined using thirty nine columns with side walls and four beams with spandrel walls. Secondly evaluating method of member ranks, which represents the level of deformation capacity of the member, is proposed. Whereas evaluated member ranks using previous methods shows too conservative deformation capacity comparing to experimental data, the proposed method is found to be an effective method for practical design procedures.

Seismic behaviour of RC columns retrofitted with textile-reinforced mortar (TRM) optimized by short PVA fibres

Textile-reinforced mortar (TRM) optimized by short polyvinyl alcohol (PVA) fibres was used as a strengthening material for seismically deficient reinforced concrete (RC) columns. Seven RC columns, including a reference column, a column strengthened with the inorganic matrix added short PVA fibres, and five columns strengthened with the optimized TRM, were subjected to low-frequency cyclic loading. The influences of the reinforcing ratio of carbon textile and axial load ratio on the seismic performance of the jacketed columns were studied. The results showed that the shear capacity and deformability of RC column respectively increased by 54.3 ∼ 55.2 % and 40.34 ∼ 78.62 % after strengthening with the optimized TRM system. Increasing the reinforcing ratio of carbon textiles in the strengthening layer, the displacement ductility and energy dissipation of the jacketed column were further enhanced. As the axial load ratio increased, the shear capacity of the jacketed column increased; however, the corresponding ductility and energy-dissipation ability decreased. The relationship between the shear contribution and material configuration of the TRM was established. The shear capacity of the TRM-strengthened columns can be estimated by a modified shear model considering the reinforcement ratio of textile and the volume content of PVA fibres.

Seismic performance analysis of adjacent eccentric structures based on PSO algorithm

Adjacent structures connected by dampers can effectively prevent collisions and attenuate the response of these structures. An early simplified model was investigated using a two-dimensional model. However, this model disregarded the effect of torsional response due to eccentricity. The eccentric arrangement of dampers owing to the non-parallel centroid between adjacent structures has not been considered in existing research. Here, the vibration equation of adjacent structures connected to a Kelvin damper was derived to study the torsional response under earthquake excitation. Furthermore, a PSO (Particle Swarm Optimization) algorithm was adopted to conduct a parametric study. Additionally, the damping effects of adjacent structures were compared using various damper layout schemes. The results show that the structural displacement was reduced by 50% by connecting dampers between adjacent structures. Placing dampers in the middle of a structure has a greater damping control effect than placing them on the side columns. However, the optimal damper layout must be chosen based on the diverse eccentric combinations and control goals of the adjacent structures. A damper can be arranged eccentrically to increase its damping control effect on an adjacent structures by 50% to 75%. The weakening of the edge effect on the damping effect should be considered when choosing the control objective for damper optimization. This weakening impact can reduce the damping effects by 50% and lead to greater deformation of the side column. The response of adjacent structures can be controlled macroscopically by utilizing the translation–torsional energy ratio as the control goal. However, a high fundamental frequency ratio of adjacent structures should be avoided.

Study on Mechanical Behavior of Fully Encased Composite Slender Columns with High-Strength Concrete Using FEM Simulation

The most common types of composite columns used in high-rise structures are concrete-filled steel tubes (CFSTs) and concrete-encased steel (CES) that are either entirely or partially encased in concrete. The attempt of this study is to develop a suitable constitutive model addressing the behavior of fully encased composite slender columns with high-strength concrete subjected to axial loading. The nonlinear finite element (FE) package ABAQUS version 6.14-2 is used to study the response of fully encased composite (FEC) slender columns. The finite element analysis (FEA) results are validated with experimental data extracted from previous experiments. Then, the parametric study is conducted on rectangular FEC columns with different shapes of encased steel encasements to investigate the axial load-carrying capacities, axial deformation, ductility, load-deformation behavior, and confinement of FEC columns. The governing parameters for the current study are the high strength of concrete (90 MPa, 100 MPa, and 120 MPa), shapes of encased steel sections (circular, I-shaped, and rectangular steel encasements), and spacing of tie bars (50 mm, 100 mm and 150 mm). 6–21% of load increment is observed by changing the concrete compressive strength. A comparison is also made between the results of reinforced concrete and FEC slender columns and 2–11% of load increment is recorded by changing the shape of structural steel and keeping other parameters constant. The results of calibrated finite element models revealed that closely spaced tie bars resulted in a good ductility of FEC column with high-strength concrete (HSC). Significant enhancements in the axial load capacity are observed in the case of FEC slender columns than in RC slender columns of the same size and shape. Ductility and residual strength after the failure of FEC columns are also observed to increase significantly with the adoption of tubular structural steel sections. However, increasing the concrete strength results in the reduction of this ductility.

DETAILED MECHANICS OF FLEXURAL RC COLUMN DEFORMATION UP TO REBAR YIELDING

Yield displacement is an important parameter in appropriately evaluating a seismic capacity of a building. To understand the detailed mechanics of flexural column deformation up to yielding of flexural rebar, deformation characteristics are measured with high resolution in a static loading test of five column specimens. Measured horizontal displacements are, then, separated into three displacement components, i.e., flexural displacement, shear displacement, and anchorage displacement, to find they are well simulated by classical flexural theory based on Bernoulli-Euler assumption, elastic shear theory considering uncracked horizontal section, and elastic deformation theory of stub considering flexural stress transferred from the column, respectively.

Strengthening RC eccentrically loaded columns by CFRP at different levels of initial load

This paper presents results obtained from test carried out to investigate the behavior of columns strengthened with CFRP laminates subjected to eccentrically applied axial loading. It is noted that when strengthening existing structures, it is often not possible to fully unload them and as a result the structural elements being strengthened are pre-loaded. In this research 10 large scale column specimens, strengthened with CFRP are investigated. Attention is focused on investigating the effect of pre-loading acting at the moment of strengthening on the recorded behavior. Each sample is initially loaded with eccentrically applied axial force, equal to 30%, 50% and 70% of the ultimate capacity. Once strengthened, the specimens were incrementally loaded until the destruction, values of strains and deflections were recorded on each loading stage. Strength, deformability and ductility parameters of columns were determined and thoroughly analyzed. Comparative analysis was carried out and the effectiveness of the strengthening is determined. It was identified, that the higher levels of initial loading decrease the strengthening effect from 31.8% to 15 % when for 30% and 70% preloading, respectively. Also, for samples with high pre-loading level the ultimate displacement at ultimate load reduced. It is important to note the increase of stiffness and decrease of deflections due to CFRP-strengthening. The presence on initial loading slightly decreases the ductility of CFRP strengthened columns (by 9–12 %). Specific features of CFRP effectiveness should be taken into account in engineering practice.

First abnormalities investigation in Mullus barbatus (Mullidae) from the Eastern Coast of Algeria

Red mullet Mullus barbatus, Linnaeus, 1758, is a benthic marine fish. Because of its wide geographic distribution and close association with sediments, red mullet is commonly used as a sentinel species for pollution assessment along the Mediterranean coast. A total of 500 specimens were examined from the Gulf of Bejaia, eastern coast of Algeria, from June 2018 to June 2019 by X-ray radiography and histopathological examination. We observed for the first time in Algeria complex spinal column deformities (kyphosis, lordosis, and scoliosis), vertebral coalescence, vertebral fusion, missing of one pelvic fin, caudal fin abnormalities, congested cheek, lymphocystis, ovary malformation, and asymmetric testis. Additionally, fibrosis, inflammatory reaction, melano-macrophage centres, necrosis, atresia, and disturbance of normal tissue were detected by histopathology examination

Numerical evaluation of impact resistance of concrete columns reinforced with GFRP bars under various axial force ratios and impact velocities

Fiber-reinforced polymer (FRP) bars have the characteristics of high strength, lightweight, and corrosion resistance, which can be used as a substitute for conventional steel bars in a corrosive environment. A three-dimensional (3D) model of the concrete column considering the dynamic increase factor of the concrete, steel bars, and FRP bars was developed using finite element (FE) method to investigate the difference of the concrete columns with steel bars and FRP bars in the impact behavior. The failure pattern, impact force, displacement, reinforcement strain, internal force, and energy of GFRP-RC and RC columns were compared. Then, the effects of the axial force ratio of 0–0.6 and the impact velocity of 1.2–5.6 m/s on the impact behavior were further discussed and an optimal axial force ratio was recommended in this study. The results showed that the impact force, internal force, and local deformation of the GFRP-RC column were slightly smaller than those of the RC column, but the duration and displacement increased. The increase in axial force ratio caused the concrete at the top and bottom of GFRP-RC columns to be crushed, whereas the impact resistance of GFRP-RC columns was best when the axial force ratio was 0.2. The more serious damage to the concrete occurred at the local impact position and both ends of the column as a response to the increase in the impact velocity. The concrete exhibited larger energy dissipation for GFRP-RC columns when subjected to different axial force ratios and impact velocities.