scholarly journals Performance of a Multi-Storey Complex Building with CFST Columns.

2020 ◽  
Vol 9 (7) ◽  
pp. 195-201
Keyword(s):  
Agricultural Land ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Steel Tube ◽  
Seismic Zone ◽  
Cross Sectional ◽  
Seismic Zones ◽  
Complex Building ◽  
Cfst Columns ◽  
Vertical Development

Due to rapid on-going horizontal development and restricted vertical development of buildings has resulted in congestion of cities and shrinkage of agricultural land, particularly in high seismic zones. For vertical development, there is a need for the construction of buildings as high as possible. The restriction to the vertical development is due to the reason that high rise structures are more vulnerable to lateral loads acting on the building resulting from the seismic events. With a background in view, the current work studies the seismic responses of a multi-storey complex building with concrete-filled steel tube columns (CFST). In present work, CFST columns of different sizes were used for the study of a Ground+12 storey building with plan dimensions 35m x 30m, situated in seismic Zone-V and medium soil type as per IS 1893-2016 classification. The Response spectrum analysis was carried out for different building models as per IS 1893:2016 provisions. E-TABS software was used for three-dimensional modelling and analysis of buildings. Several response parameters like fundamental time period, maximum storey displacement, maximum storey drift, storey shear and overturning moment are considered in this study to evaluate the performance of the building. It was concluded that CFST columns perform well for high seismic zones even at smaller cross-sectional dimensions.

Seismic Design and Construction Practices for RC Structural Wall Buildings

2012 ◽  
Vol 28 (1_suppl1) ◽  
pp. 245-256 ◽  
Author(s):  
Leonardo M. Massone ◽  
Patricio Bonelli ◽  
René Lagos ◽  
Carl Lüders ◽  
Jack Moehle ◽  
...  
Keyword(s):  
Linear Models ◽  
Principal Direction ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Load Resistance ◽  
Floor Plan ◽  
Structural Walls ◽  
Cross Sectional ◽  
Structural Wall ◽  
Wall Area

Reinforced concrete buildings utilizing structural walls for lateral load resistance are the predominant form of construction in Chile for buildings over four stories. Typical buildings include a large number of walls, with ratios of wall cross-sectional area to floor plan area of roughly 3% in each principal direction. Based on the good performance of RC buildings in the March 1985 earthquake, requirements for closely spaced transverse reinforcement at wall boundaries were excluded when Chile adopted a new concrete code in 1996 based on ACI 318-95. In recent years, use of three-dimensional linear models along with modal response spectrum analysis has become common. Since 1985, nearly 10,000 new buildings have been permitted. Although the newer buildings have similar wall area to floor plan areas as older buildings, newer walls are thinner and buildings are taller, leading to significantly higher wall axial load ratios.

scholarly journals Vision-Based Three-Dimensional Reconstruction and Monitoring of Large-Scale Steel Tubular Structures

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Yunchao Tang ◽  
Mingyou Chen ◽  
Yunfan Lin ◽  
Xueyu Huang ◽  
Kuangyu Huang ◽  
...  
Keyword(s):  
Point Cloud ◽  
Large Scale ◽  
Learning Algorithm ◽  
Vision System ◽  
Three Dimensional ◽  
Steel Tube ◽  
Dynamic Monitoring ◽  
Complex Environments ◽  
Cross Sectional ◽  
Vision Measurement

A four-ocular vision system is proposed for the three-dimensional (3D) reconstruction of large-scale concrete-filled steel tube (CFST) under complex testing conditions. These measurements are vitally important for evaluating the seismic performance and 3D deformation of large-scale specimens. A four-ocular vision system is constructed to sample the large-scale CFST; then point cloud acquisition, point cloud filtering, and point cloud stitching algorithms are applied to obtain a 3D point cloud of the specimen surface. A point cloud correction algorithm based on geometric features and a deep learning algorithm are utilized, respectively, to correct the coordinates of the stitched point cloud. This enhances the vision measurement accuracy in complex environments and therefore yields a higher-accuracy 3D model for the purposes of real-time complex surface monitoring. The performance indicators of the two algorithms are evaluated on actual tasks. The cross-sectional diameters at specific heights in the reconstructed models are calculated and compared against laser rangefinder data to test the performance of the proposed algorithms. A visual tracking test on a CFST under cyclic loading shows that the reconstructed output well reflects the complex 3D surface after correction and meets the requirements for dynamic monitoring. The proposed methodology is applicable to complex environments featuring dynamic movement, mechanical vibration, and continuously changing features.

scholarly journals DETERMINATION OF STRESS-STRAIN STATE OF SHORT ECCENTRICALLY LOADED CONCRETE-FILLED STEEL TUBULAR (CFST) COLUMNS USING FINITE ELEMENT METHOD WITH REDUCING THE PROBLEM FROM THREE-DIMENSIONAL TO TWO-DIMENSIONAL

2020 ◽  
Vol 8 (4) ◽  
pp. 87-94
Author(s):  
Batyr Yazyev ◽  
Pavel Urvachev ◽  
Viacheslav Chepurnenko ◽  
Arthur Avakov
Keyword(s):  
Finite Element Method ◽  
Finite Elements ◽  
Strain State ◽  
Three Dimensional ◽  
Steel Tube ◽  
Two Dimensional ◽  
Tubular Columns ◽  
Cfst Columns ◽  
3D Solid

The article presents the derivation of the FEM equations, which make possible to calculate short concrete-filled steel tubular columns in a plane elastic formulation. Steel tube is modeled by 1D bar finite elements. The obtained results are compared with the results of calculations using 3D solid and shell finite elements.

scholarly journals Analysis of strengthened short deficient rubberized concrete-filled steel tubular columns

2020 ◽  
Vol 15 (55) ◽  
pp. 1-19
Author(s):  
Fady Elshazly ◽  
Suzan Mustafa ◽  
Hesham Fawzy
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Compressive Load ◽  
Element Model ◽  
Crumb Rubber ◽  
Steel Tube ◽  
Fine Aggregate ◽  
Rubberized Concrete ◽  
Structural Behaviour ◽  
Cfst Columns

Concrete-filled steel tubular (CFST) columns are broadly used in many structural systems for their well-known merits. This paper presents a finite element investigation on the structural behaviour of short circular deficient steel tubes filled with rubberized concrete (RuC), under axial compressive load. To accomplish this study, a validation of the proposed three-dimensional nonlinear finite element model; using ANSYS software; was carried out showing good accurateness. The analysis involved two different concrete mixes with 5% and 15% replacement of fine aggregate volume with crumb rubber particles. Columns strength reduction due to horizontal or vertical deficiencies was handled by increasing the thickness of the steel tube or wrapping the columns with two different types of FRP sheets. Five strengthening arrangements were studied using GFRP sheets and CFRP sheets. The results indicated that the ultimate bearing capacity of the RuCFST columns was increased with increasing the steel tube thickness. application of FRP sheets for strengthening the deficient RuCFST columns efficiently managed to retrieve the strength-lost due to either horizontal or vertical deficiency. Moreover, an enhancement in the columns’ ductility was observed especially when using GFRP sheets

scholarly journals Simplified numerical modelling of rectangular concrete-filled steel columns, beams and beam-columns

2018 ◽  
Author(s):  
Zhong Tao ◽  
Utsab Katwal ◽  
Kamrul Hassan ◽  
Wen-Da Wang
Keyword(s):  
Numerical Modelling ◽  
Three Dimensional ◽  
Numerical Data ◽  
Steel Tube ◽  
Material Models ◽  
Beam Columns ◽  
Steel Columns ◽  
Wide Range ◽  
Cfst Columns ◽  
Stub Columns

Because of its computational efficiency, simplified numerical modelling is the preferred method to simulate structural frames for routine design. As for concrete-filled steel tubular (CFST) columns, fibre beam element (FBE) modelling is often used in the simplified simulation. However, the accuracy of FBE modelling is greatly affected by the accuracy of the input material models, which should directly account for the interaction between the steel tube and core concrete. In this paper, simple yet accurate material models of steel and concrete are proposed for rectangular CFST columns by utilising a large amount of numerical data generated from detailed three-dimensional finite element modelling of stub columns. The material models are then incorporated into the simplified FBE simulation of rectangular CFST columns, beams and beam-columns. The accuracy of the simplified FBE simulation is verified by a wide range of experimental results on rectangular CFST stub columns, slender columns, beams and beam-columns.

scholarly journals Study of Structural Irregularities in different Seismic Zones using Response Spectrum Analysis

2021 ◽  
Vol 9 (8) ◽  
pp. 1410-1417
Author(s):  
Vedant Kale
Keyword(s):  
Spectrum Analysis ◽  
Response Spectrum ◽  
Three Dimensional ◽  
Lateral Force ◽  
Lateral Loading ◽  
Seismic Load ◽  
Response Spectrum Analysis ◽  
Seismic Zones ◽  
Stress Resultant ◽  
Structural Irregularities

Abstract: The Indian Standard code IS-1893: 2002 (Part-I) defines various types of structural irregularities. The code suggests a special approach of study for irregular structures. The earthquake effect leads to the damage the property and many people loss their life. So, we've to understand the structural performance under seismic load before construction. In this study varying plan irregularities which are often inevitable thanks to building requirements and architectural imperatives, and having a serious impact on building costs are investigated. The objective of the project is to carry out Response spectrum analysis of two RCC buildings is to be done in four different seismic zones of India (i.e., Zone-2, Zone-3, Zone-4, Zone-5). ETABS model of G+10 RCC with Varying Geometry plan is considered in this analysis. The analysis is done using Extended Three-Dimensional Analysis of Building System software. Various response parameters like lateral force, story drift, Displacement are often determined. The evaluation of response of structures subjected to lateral loading with the help of frequency and the magnitude of stress resultant, is also included in the scope of this paper. Keywords: Plan irregularity, Vertical geometric irregularities Response spectrum method, ETABS, Structural Irregularities, Lateral Loading, Non-Linear Analysis, Storey Drift, Storey Displacement.

scholarly journals Experimental study on seismic behavior of full scale square concrete filled steel tubular stocky columns

2021 ◽  
Vol 272 ◽  
pp. 02024
Author(s):  
Jin Liu ◽  
Liang Jian ◽  
Du Xiuli
Keyword(s):  
Shear Failure ◽  
Plastic Hinge ◽  
Local Buckling ◽  
Steel Tube ◽  
Calculation Model ◽  
Full Scale ◽  
Cross Sectional ◽  
Short Columns ◽  
Cfst Columns ◽  
Plastic Hinge Length

This study mainly presented a pseudo-static experiment on two full-scale square CFST short columns with the cross-sectional width of 600 mm under combined constant axial load and cyclic lateral load. The seismic performance of the two full-scale CFST columns were investigated. Meanwhile, the plastic hinge length of the specimens was discussed. The test results presented that the specimens suffered bend-shear failure. The local buckling of steel tube occurred at the end of the specimens and the core concrete crushed. The safety redundancy of lateral bearing capacity decreased in full-scale specimen. By the method of physical observation, the plastic hinge length Lp1 was determined mainly according to the range of the local buckling of steel tube. There had a great difference between the prediction of plastic hinge lengths by the existing calculation model and the plastic hinge lengths obtained by the test.

scholarly journals Accuracy and Reproducibility of Facial Measurements of Digital Photographs and Wrapped Cone Beam Computed Tomography (CBCT) Photographs

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 757
Author(s):  
Maged Sultan Alhammadi ◽  
Abeer Abdulkareem Al-mashraqi ◽  
Rayid Hussain Alnami ◽  
Nawaf Mohammad Ashqar ◽  
Omar Hassan Alamir ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam Computed Tomography ◽  
High Reliability ◽  
Three Dimensional ◽  
Cone Beam ◽  
Cross Sectional ◽  
Facial Profile ◽  
Digital Photographs ◽  
Gonial Angle

The study sought to assess whether the soft tissue facial profile measurements of direct Cone Beam Computed Tomography (CBCT) and wrapped CBCT images of non-standardized facial photographs are accurate compared to the standardized digital photographs. In this cross-sectional study, 60 patients with an age range of 18–30 years, who were indicated for CBCT, were enrolled. Two facial photographs were taken per patient: standardized and random (non-standardized). The non-standardized ones were wrapped with the CBCT images. The most used soft tissue facial profile landmarks/parameters (linear and angular) were measured on direct soft tissue three-dimensional (3D) images and on the photographs wrapped over the 3D-CBCT images, and then compared to the standardized photographs. The reliability analysis was performed using concordance correlation coefficients (CCC) and depicted graphically using Bland–Altman plots. Most of the linear and angular measurements showed high reliability (0.91 to 0.998). Nevertheless, four soft tissue measurements were unreliable; namely, posterior gonial angle (0.085 and 0.11 for wrapped and direct CBCT soft tissue, respectively), mandibular plane angle (0.006 and 0.0016 for wrapped and direct CBCT soft tissue, respectively), posterior facial height (0.63 and 0.62 for wrapped and direct CBCT soft tissue, respectively) and total soft tissue facial convexity (0.52 for both wrapped and direct CBCT soft tissue, respectively). The soft tissue facial profile measurements from either the direct 3D-CBCT images or the wrapped CBCT images of non-standardized frontal photographs were accurate, and can be used to analyze most of the soft tissue facial profile measurements.

scholarly journals A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

2021 ◽  
Vol 11 (8) ◽  
pp. 3404
Author(s):  
Majid Hejazian ◽  
Eugeniu Balaur ◽  
Brian Abbey
Keyword(s):  
Molecular Dynamics ◽  
Flow Rate ◽  
Numerical Study ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Liquid Jets ◽  
Mixing Efficiency ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

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