scholarly journals Novel Fuzzy-Based Optimization Approaches for the Prediction of Ultimate Axial Load of Circular Concrete-Filled Steel Tubes

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 629
Author(s):  
Jinsong Liao ◽  
Panagiotis G. Asteris ◽  
Liborio Cavaleri ◽  
Ahmed Salih Mohammed ◽  
Minas E. Lemonis ◽  
...  
Keyword(s):  
Axial Compression ◽  
Structural Engineering ◽  
Model Development ◽  
Experimental Tests ◽  
Accurate Estimation ◽  
The Novel ◽  
Concrete Technology ◽  
Hybrid Techniques ◽  
Improved Performance ◽  
Concrete Filled Steel Tubes

An accurate estimation of the axial compression capacity of the concrete-filled steel tubular (CFST) column is crucial for ensuring the safety of structures containing them and preventing related failures. In this article, two novel hybrid fuzzy systems (FS) were used to create a new framework for estimating the axial compression capacity of circular CCFST columns. In the hybrid models, differential evolution (DE) and firefly algorithm (FFA) techniques are employed in order to obtain the optimal membership functions of the base FS model. To train the models with the new hybrid techniques, i.e., FS-DE and FS-FFA, a substantial library of 410 experimental tests was compiled from openly available literature sources. The new model’s robustness and accuracy was assessed using a variety of statistical criteria both for model development and for model validation. The novel FS-FFA and FS-DE models were able to improve the prediction capacity of the base model by 9.68% and 6.58%, respectively. Furthermore, the proposed models exhibited considerably improved performance compared to existing design code methodologies. These models can be utilized for solving similar problems in structural engineering and concrete technology with an enhanced level of accuracy.

scholarly journals Suspended Sediment Modeling Using a Heuristic Regression Method Hybridized with Kmeans Clustering

2021 ◽  
Vol 13 (9) ◽  
pp. 4648
Author(s):  
Rana Muhammad Adnan ◽  
Kulwinder Singh Parmar ◽  
Salim Heddam ◽  
Shamsuddin Shahid ◽  
Ozgur Kisi
Keyword(s):  
Clustering Algorithm ◽  
Suspended Sediments ◽  
Ecological Impacts ◽  
Accurate Estimation ◽  
Data Sets ◽  
The Novel ◽  
Neuro Fuzzy ◽  
Adaptive Regression ◽  
Novel Method ◽  
Model Training

The accurate estimation of suspended sediments (SSs) carries significance in determining the volume of dam storage, river carrying capacity, pollution susceptibility, soil erosion potential, aquatic ecological impacts, and the design and operation of hydraulic structures. The presented study proposes a new method for accurately estimating daily SSs using antecedent discharge and sediment information. The novel method is developed by hybridizing the multivariate adaptive regression spline (MARS) and the Kmeans clustering algorithm (MARS–KM). The proposed method’s efficacy is established by comparing its performance with the adaptive neuro-fuzzy system (ANFIS), MARS, and M5 tree (M5Tree) models in predicting SSs at two stations situated on the Yangtze River of China, according to the three assessment measurements, RMSE, MAE, and NSE. Two modeling scenarios are employed; data are divided into 50–50% for model training and testing in the first scenario, and the training and test data sets are swapped in the second scenario. In Guangyuan Station, the MARS–KM showed a performance improvement compared to ANFIS, MARS, and M5Tree methods in term of RMSE by 39%, 30%, and 18% in the first scenario and by 24%, 22%, and 8% in the second scenario, respectively, while the improvement in RMSE of ANFIS, MARS, and M5Tree was 34%, 26%, and 27% in the first scenario and 7%, 16%, and 6% in the second scenario, respectively, at Beibei Station. Additionally, the MARS–KM models provided much more satisfactory estimates using only discharge values as inputs.

Experimental and numerical investigation on ultimate strength of four-legged latticed columns

2021 ◽  
pp. 136943322110015
Author(s):  
Yinqi Li ◽  
Feng Liu ◽  
Wenming Cheng ◽  
Huasen Liu
Keyword(s):  
Ultimate Strength ◽  
Structural Engineering ◽  
Analytical Techniques ◽  
Experimental Tests ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Compressive Loads ◽  
Initial Geometric Imperfections ◽  
Combined Data ◽  
Loading Eccentricity

Latticed built-up columns are applied more extensively than solid columns in structural engineering because of their excellent load-carrying capacity and light weight. Studies on the bearing capacity of latticed columns, particularly multiple-legged latticed columns, need to be conducted in detail. In this investigation, seven four-legged latticed column specimens of different bar sections, bar distributions and loading eccentricities under compressive loads were subjected to experimental tests. The initial geometric imperfections of the legs and bars were measured and introduced into the FE numerical method. The experimental results were then compared with those of Geometrical and Material Non-Linear Analysis with Imperfection in ABAQUS software. The combined data indicate that the bar section, bar distribution and loading eccentricity significantly influenced the ultimate strength of four-legged latticed columns, producing maximum variations of 105.67%, 65.7% and 48.48%, respectively. This investigation demonstrates the influence of lacing bars and improves the results obtained from FE numerical analytical techniques.

Punching shear behaviour of flat slabs with different reinforcement schemes: openings and rectangularity effects

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Donia Salman ◽  
Rabab Allouzi ◽  
Nasim Shatarat
Keyword(s):  
Structural Engineering ◽  
Experimental Tests ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Behaviour ◽  
Cross Sectional ◽  
Content Type ◽  
Flat Slabs ◽  
Reinforced Concrete Slabs ◽  
Rectangular Columns

PurposeThe main goal is to investigate the effect of size and location of opening and column size on the punching shear strength. Openings are often needed in order to install mechanical and electrical services. This process takes away part of the concrete volume which is responsible for resisting the shear forces and any unbalanced moment. Furthermore, the application of rectangular columns in flat slabs is commonly used in practice as they provide lateral stiffness to the building. They are also utilised in garages and multi-storey buildings where these elongated cross-sectional columns reduce the effective span length between adjacent columns.Design/methodology/approachThis research is a numerical-based investigation that is calibrated based on a thirteen previously tested and numerically calibrated slab specimens with no openings. A parametric study is conducted in this study to consider the effect of other parameters, which are the size and location of opening and the rectangularity ratio of column in order to evaluate their effect on the punching shear capacity. A total of 156 models are developed to study these factors. Additionally, the predicted shear carrying capacity of the simulated slabs is calculated using the ACI318–19 and Eurocode (EC2-04) equation.FindingsThe presence of openings reduced the punching shear capacity. The small opening's location and orientation have almost no effect except for one slab. For slabs of large openings, the presence of openings reduced the punching capacity. The punching capacity is higher when the openings are farther from the column. The numerically obtained results of slabs with rectangular columns show lower punching capacity compared to slabs of squared columns with the same length of the punching shear control perimeter. The punching capacity for all slabs is predicted by ACI318–19 and Eurocode (EC2-04) and it is found that Eurocode (EC2-04) provided a closer estimation.Originality/valueThe slabs considered for calibration were reinforced with four different punching shear reinforcement configurations, namely; ordinary closed rectangular stirrups, rectangular spiral stirrups, advanced rectangular spiral stirrups and circular spiral. Generally, there has been limited research on concrete flat slabs with openings in comparison with other subjects related to structural engineering (Guan, 2009) and no research on punching shear with openings of slabs reinforced with these reinforcement schemes. The available research focussed on the effects of openings on the flexural behaviour of reinforced concrete slabs includes Casadei et al. (2003), Banu et al. (2012) and Elsayed et al. (2009). In addition, experimental tests that examined slabs supported on rectangular columns are very limited.

University budgeting: internal versus external transparency

2020 ◽  
Vol 17 (4) ◽  
pp. 589-617
Author(s):  
Maria C. Conesa Carril ◽  
Nieves Gómez Aguilar ◽  
Manuel Larrán Jorge
Keyword(s):  
Key Management ◽  
Model Development ◽  
Management Tool ◽  
Budget Process ◽  
The Novel ◽  
Content Type ◽  
Documentary Analysis ◽  
The University ◽  
Budgeting Process

Purpose The analysis intends to clarify whether higher education institutions place as much value on internal transparency as on external transparency. This study aims to analyze the university budgeting process as a reflection of internal transparency. It also aims to identify the weaknesses of the budgeting process regarding transparency in order to improve decision-making. Design/methodology/approach A case study that applies mixed methods – documentary analysis, observations and interviews – has been conducted. To study internal transparency, the model of three levels of transparency of Biondi and Lapsley (2014) has been applied to the budgeting process of a university. Then, the results have been compared to the external transparency of this institution. Findings While external transparency is achieved, internal transparency in the budgeting process is far from optimal in the case of study. An improvement in transparency of the budget process can promote the engagement of stakeholders in the process and achieve better governance. Research limitations/implications The general inductive approach is not as strong as other approaches in the area of theory or model development. However, it does provide a simple approach for deriving findings linked to this research’s questions. Practical implications Trust issues and external accountability appear to be more relevant than internal transparency for universities. However, improving the three levels of transparency along the budgeting process could motivate collegiate members to reinforce accountability, as it requires them to effectively communicate their actions and decisions to their represented. Originality/value This paper seeks to situate transparency as an attribute of university governance, contributing to the scarce literature on transparency, internal and external, in the university. The study compares the approach of this university to external transparency – which relates to accountability – with internal transparency – a concept that links to corporate governance. This study uses the novel lens of Biondi and Lapsley model (2014) to study internal transparency, focussing on university budgeting as a key management tool.

scholarly journals Development of Mobile Application for Sustainable Creative Tourism Assessment using Confirmatory Factor Analysis Approach

2019 ◽  
Vol 13 (06) ◽  
pp. 27
Author(s):  
Chitralada Suphachaimongkol ◽  
Chavalit Ratanatamskul ◽  
Siriwan Silapacharanan ◽  
Patcha Utiswannakul
Keyword(s):  
Factor Analysis ◽  
Confirmatory Factor Analysis ◽  
Mobile Application ◽  
Assessment Tool ◽  
Model Development ◽  
Development Stage ◽  
The Novel ◽  
Confirmatory Factor ◽  
Tourism Enterprises ◽  
Delphi Techniques

<span>Creative tourism has received increasing attention. At present, the concept of creative tourism is still in development stage since there are few or no indicators for assessing the potential of creative tourism to area-based sustainable goals. This document aims to introduce the process of mobile application for sustainable creative tourism (SCT) model development using confirmatory factor analysis (CFA) approach. The study was divided into 4 phases. The first phase involved establishing elements, indicators and criteria drawn from some previous studies and the opinions of experts’ judgement in this study. Secondly, indicators and criteria were selected by using Delphi technique. Thirdly, the indicators and criterias were confirmed by utilizing CFA, Finally, the prototype of SCT mobile application assessment tool is proposed for SCT in this study, based on CFA. Tools for the study included: 1) structured questionnaire from reviews of literature for interviewing the expert, 2) questionnaire for Delphi techniques among the experts for collecting an opinion about the selection of the indicators, and 3) a questionnaire to assess the possibility of data collection concerning the components and indicators of SCT. 300 samples from creative tourism enterprises from all around Thailand were collected and 253 were responded. Data analysis was conducted by using descriptive statistics and CFA. The study found that SCT model consists of 8 components and 36 indicators. The finding from our research shows that it is eligible to establish the novel SCT assessment indicators. The result of SCT application model is appropriate to develop mobile application for SCT assessment tool. </span>

A Feedback Linearization-Based Motion Controller for a UWMR with Experimental Evaluations

Robotica ◽  
2019 ◽  
Vol 37 (6) ◽  
pp. 1073-1089 ◽  
Author(s):  
Luis Montoya-Villegas ◽  
Javier Moreno-Valenzuela ◽  
Ricardo Pérez-Alcocer
Keyword(s):  
Feedback Linearization ◽  
Vision System ◽  
Experimental Tests ◽  
Experimental Result ◽  
The Novel ◽  
Tracking Accuracy ◽  
Motion Controller ◽  
Wheeled Mobile Robots ◽  
Feedback Linearization Approach ◽  
Error State

SummaryIn this paper, the feedback linearization approach is used to introduce a motion controller for unicycle-type wheeled mobile robots (UWMRs). The output function is defined as a linear combination of the error state. The novel scheme is firstly tested in numerical simulation and compared with its corresponding experimental result. Three controllers are taken from the literature and compared to the proposed approach by means of experiments. The gains of the experimentally tested controllers are selected to obtain identical energy consumption. The Optitrack commercial vision system and Pioneer P3-DX UWMR are used in real-time experimental tests. In addition, two sets of experimental results for different motion tasks are provided. The results show that the proposed controller presents the best tracking accuracy.

Damage Assessment of Rectangular Concrete-Filled Steel Tubes for Performance-Based Design

2004 ◽  
Vol 20 (4) ◽  
pp. 1317-1348 ◽  
Author(s):  
Cenk Tort ◽  
Jerome F. Hajjar
Keyword(s):  
Experimental Tests ◽  
Steel Tube ◽  
Performance Based Design ◽  
Damage State ◽  
Damage Functions ◽  
Experimental Database ◽  
Beam Columns ◽  
Damage States ◽  
Concrete Filled Steel Tubes ◽  
Different Levels

Damage evolution of rectangular concrete-filled steel tube (RCFT) column and beam-column members as documented in experimental tests is presented in this paper. An experimental database was first constructed that included RCFT tests that were reported in detail in the worldwide literature. Based on the experimental data, appropriate damage states for RCFT members, connections, and frames were defined at different levels of loading. For each damage state, the performance of the specimens was documented quantitatively with the use of deformation-based damage functions, energy-based damage functions, and ductility functions developed in this work. The paper then documents how to use these damage measures to assess capacity of RCFT columns and beam-columns within the context of a performance-based design methodology.

Sign in / Sign up

Export Citation Format

Share Document