Design Of Columns Research Articles

Influence of steel-to-concrete ratio on sustainable column design in Saudi Arabia

This study investigates the impact of the steel-to-concrete ratio in building columns on environmental factors, embodied energy, and cost estimations in a hotel construction scenario in the Eastern Province of Saudi Arabia. This study focuses on the production (A1–A3) and construction (A4–A5) stages, omits the use and disposal phases, and extensively examines the material components and their environmental implications. It evaluates the environmental impact of diverse column types. Revit 2022 (Autodesk®) is used to model scenarios with steel-to-concrete ratios of 1.2 %, 1.5 %, and 1.8 %. The most cost-effective steel-to-concrete ratio is 1.2 %, which reduces the embodied carbon and energy by 32 % and 35 %, respectively. A steel-to-concrete ratio of 1.8 % increases the embodied carbon and energy by 13 % and 14 %, respectively, compared with the base case. This indicates the significant contributions of concrete and steel to the embodied carbon and energy during the production stages. This study emphasizes the diminishing cost effectiveness of increasing the steel ratio beyond 1.2 % and highlights the importance of balancing steel usage and cost efficiency in column construction.

Redesign Struktur Atas Beton Bertulang Dan Atap Baja Pada Pembangunan Gedung Serbaguna dan Olahraga Universitas Subang

Subang University (Unsub) is the first university in Subang Regency. On the Subang University campus itself, which consists of several buildings, there is no presentative room that can be used for various activities (multipurpose room). Therefore, it is necessary to re-design the space in a presentative manner in accordance with the construction rules in accordance with the applicable SNI. The re-designminimizes damage to building structures that do not meet the applicable SNI standards, in accordancewith the provisions of SNI 1726:20212 (Procedures for Earthquake Resistance Planning for BuildingStructures) as a Geotechnical Based on Building Structures, SNI 1727: 2013 (Minimum Free StandardsUsed for Building Design), and SNI 2847:2013 (Requirements for Structural Berton Used for Buildings),and the SNI regulations are divided into 4 load categories, such as: Dead Load, Live Load, Wind Loadand Earthquake Load, and used SAP 2000 to process the redesign analysis. The results of the re-designshowed that the design of the dimension column had the highest ratio (0.971), with 2 rafter designs (WF600x200x11x17) (WF 500x200x10x16), with a lot of upper reinforcement (8D22) and lowerreinforcement (5D22).

Evaluation of Link Overstrength Factor for the Seismic Design of Eccentrically Braced Frames

In eccentrically braced frames (EBFs), inelastic behavior is only permitted in the links. All members, except for the links, are designed according to the capacity design concept by using the link overstrength factor, Ω, so that they remain elastic even when the links develop their ultimate strength (including the strain-hardening effect). AISC 341 specifies that the Ω factor of link members must be 1.25 for beam and brace design and 1.1 for column design. In this study, the relevance of the current Ω factor was investigated. A total of 471 K-braced EBF systems with various conditions were designed using a multi-objective optimization technique, and nonlinear dynamic analyses were performed to evaluate the Ω factor. The results indicate that it is reasonable to use the current Ω factor for the design of beam outside link and brace; however, it leads to an overestimation of axial force in columns, especially in the lower stories of tall buildings. From the analysis results, a new Ω factor equation for column design was proposed. It was demonstrated that the structural quantities of 15-story frames designed using the proposed equation decreased by an average of 19% compared to those designed using the current Ω factor.

Investigating the axial compressive behavior of cruciform CFST columns: An experimental study

Concrete-filled steel tube (CFST) columns enhance seismic resistance, enabling lighter-weight structures with improved fire performance. This study investigates the axial performance of cruciform CFST columns using three half-scale experiments. The cruciform sections were internally configured as unstiffened (UnS-CFST), stiffened (S-CFST), and multicell (M-CFST). Failure mode, stress, displacement, ductility, and strength were evaluated to determine the maximum load-bearing capacity. Compared to UnS-CFST columns, S-CFST and M-CFST exhibited improved ductility and axial compressive performance. The study also looks at how the proposed method for cruciform sections compares to existing design standards for square and circular CFST columns, such as AIJ, EC4, GB 50936–2014, CECS 159:2004, ACI 318R-05, and AS3600–2001. A novel method for determining the maximum load capacity of cruciform CFST columns is proposed, achieving an accuracy of approximately 95 % compared to experimental results. This novel method facilitates the design of cruciform CFST columns.

Slope stability/instability analysis of advanced nanocomposite reinforced column structure under mechanical loading via coupled Carrera unified formulation, layer-wise and Laplace transform approaches

This study presents a comprehensive investigation into the slope stability and instability of column structures made of Triply Periodic Minimal Surfaces (TPMS) under mechanical loading. TPMS structures, known for their high strength-to-weight ratio, are increasingly used in engineering applications, particularly in lightweight structures. However, their stability behavior under complex loading conditions remains largely unexplored. To address this gap, we employ a coupled approach integrating the Carrera Unified Formulation (CUF), the Layer-Wise (LW) theory, and Laplace Transform techniques. The CUF framework, known for its versatility in modeling structural behavior across different geometrical and loading configurations, is utilized to capture the mechanical response of the TPMS-based columns. The LW theory further enhances the model by accurately representing the through-thickness behavior, particularly crucial for layered or composite TPMS structures. Finally, the Laplace Transform approach is applied to efficiently solve the governing differential equations, reducing the computational complexity of time-dependent mechanical analyses. A parametric study investigates the influence of various geometrical parameters, material properties, and loading conditions on the stability of the structures. The results highlight the critical factors influencing slope stability, including the interplay between the TPMS geometry and material distribution. Moreover, the findings offer insights into failure mechanisms, providing a basis for optimizing the design of TPMS-based columns for enhanced mechanical performance. This work contributes to advancing the theoretical understanding of TPMS structures, offering novel methodologies for slope stability analysis in complex mechanical systems.

Application of Multiple Linear Regression Method in Steel Column Design under Combined Loading

The article explores using multiple linear regression (MLR) approach to predict the cross-section of beam-column steel members. These members are complex in design, as they must withstand bending and axial forces. The design process involves multiple safety checks according to design standards. The first step in the design procedure is to calculate and verify the axial capacity of the member. Following that, the flexural capacity is calculated. Finally, the combined load capacity is examined, often involving a trial-and-error process. If the initially selected section cannot withstand the applied forces, a new section must be chosen, and the calculations must be repeated. This study employs a multiple linear regression approach to investigate the relationship between member properties (such as length and cross-section) and load design parameters (axial and bending forces). The primary objective is to predict the beam-column steel member’s elastic section modulus (Sx). The regression equation derived from the study is as follows: Sx = 18.000L + 6.839Pr + 47.193Mr – 129.093, with an R-square value of 0.985. The histogram of the equation exhibits symmetry and a standard distribution, while the typical probability plot demonstrates a relatively linear trend. Two examples are presented to evaluate the efficiency of the regression equation. The first example confirms the efficiency of the equation by determining the cross-sectional size by employing the regression equation and using it to verify the safety according to EIT design standards. The second example is the application of the equation for estimating the size of other types of steel members. This study suggests that the regression equation can effectively predict the size of beam-column steel members, providing reliable results for practical design applications.

Buckling load of heavy columns with variable cross section and flexible end restraints

AbstractEffective and economical design of heavy columns, taking into account their own self weight is a common problem in engineering. The degree of restraint provided at the ends of the column should also be taken into account and it is addressed by adding rotational and/or translational springs to simulate several levels of fixity. In this work results are given for five different combinations of boundary conditions at the two ends, and for several restraint rigidities at the supports. An approximate solution using Rayleigh's method is presented and compared to numerical finite element results and to the exact solution previously derived for general cases of variable cross section columns with variable axial force.

Structural Reuse of Decommissioned Ski Lift Steel Trusses for Load-Bearing Applications

The ongoing effects of climate change have led to a rise in global temperature, significantly reducing snow cover and resulting in the abandonment of numerous ski areas across Switzerland. As a result, many ski lifts have been decommissioned and left to deteriorate due to lenient local regulations. To address this issue, this paper presents a case study approach to repurposing steel trusses from abandoned ski lifts for a new structural application within the building industry. The design, sourcing, and construction of a new load-supporting column are described, focusing on reusing the ski lift steel trusses as a whole, without dismantling them into their components. After collection, these elements are adapted to comply with current building standards. By pouring out the hollow structure with the recently developed building material Cleancrete ©, a new load-bearing structure is developed. A comprehensive life cycle assessment (LCA) demonstrates the environmental performance of the steel–Cleancrete hybrid construction, which achieves a global warming potential (GWP) of 536.58 kg CO2-eq. In comparison, alternative designs using wood and concrete exhibited GWP values of 679.45 kg CO2-eq, +26.6%, and 1593.72 kg CO2-eq, +197.02%, respectively. These findings suggest that repurposing abandoned ski lift structures can significantly contribute to sustainable building practices, waste reduction, and the promotion of circular economy principles. The process outlined in this paper holds potential for future applications, particularly in the reuse of other steel components, ensuring continued circularity even as the supply of ski lift structures may dwindle.

Maximizing sensitivity and selectivity in LC × LC-HRMS for pesticide analysis via exploitation of per-aqueous liquid chromatography

Accurate monitoring of pesticide residues at minimal concentrations is imperative for adherence to stringent regulatory standards in numerous countries. This study presents an innovative methodology employing comprehensive two-dimensional liquid chromatography coupled with high-resolution mass spectrometry (LC × LC-HRMS). The approach ensures high sensitivity and selectivity in detecting targeted compounds. A pivotal component of this methodology is the utilization of per-aqueous liquid chromatography (PALC) as the first dimension, facilitating the use of water-based mobile phases and addressing solvent mismatch issues. The second dimension employs reversed-phase liquid chromatography (RPLC), enhancing the separation of compounds. PALC proves instrumental in refocusing and enables the practical application of narrow-diameter columns (1.5 mm I.D.). This column design permits a direct split-free connection of the LC × LC to an electrospray-based mass spectrometer (ESI-MS), contributing to heightened sensitivity. The MS acquisition is performed in a targeted single-ion monitoring mode, ensuring reliable quantification and identification of the pesticide compounds. A comprehensive evaluation of key performance metrics, including signal-to-noise ratio, limit of detection, and response linearity, is conducted. The methodology achieves a limit of detection below the ng mL−1 and exhibits response linearity within the concentration range of 1–100 ng mL−1. The robustness of the approach is further demonstrated through intra-day and inter-day repeatability validations. Furthermore, the platform is finally tested on a surface water sample. This study not only introduces an advanced analytical methodology for pesticide multi-residue analysis but also underscores the significance of PALC in enhancing sensitivity by facilitating the use of smaller-diameter columns and water-based mobile phases, along with the role of RPLC in enhancing separation. The proposed approach showcases promising results in achieving detection limits that match the stringent regulatory standards and reliable quantification for effective pesticide residue monitoring.

Homogeneous reactive distillation: The influence of pressure drop on separation and reaction kinetics

This study investigates the Total Annual Cost (TAC) optimization of a reactive distillation (RD) process for methyl acetate (MA) production as a function of tray pressure drop, focusing on the trade-off between chemical reaction kinetics and separation efficiency. The analysis examines how variations in column diameter and weir height influence the TAC across different liquid hold-ups with and without incorporating a tray pressure drop in the simulations. Results indicate that for larger liquid hold-ups, the decrease in separation efficiency predominates over kinetic advantages, leading to higher energy costs when pressure drop is considered. Despite the loss in separation efficiency with a high weir height, a pressure drop-incorporated column design featuring a high weir height and small diameter is shown to achieve lower TAC due to the comparatively lower installed costs. A reduction of tray liquid hold-up of more than 50 % is found for the optimal column design in the considered case study when the tray pressure drop is considered. A sensitivity analysis towards a hypothetical infinite fast reaction is conducted to illustrate how the energy costs are affected by the kinetic rate of the chemical reaction.

Rigorous design and economic optimization of reactive distillation column considering real liquid hold-up and hydraulic conditions of industrial device

The liquid hold-up in a reactive distillation (RD) column not only has a significant impact on the extent of reactions, but also affects the pressure drop and hydraulic conditions in the column. Therefore, the liquid hold-up would be a critical design factor for RD columns. However, the existing design methods for RD columns typically neglect the influence of considerable amount of liquid hold-up in downcomers owing to the difficulties of solving a large-scale nonlinear model system by considering downcomer hydraulics, resulting in significant deviations from actual situation and even operation infeasibility of the designed column. In this paper, a pseudo-transient (PT) RD model based on equilibrium model considering tray hydraulics was established for rigorous simulation and optimization of RD plate columns considering the liquid hold-up both in downcomers and column trays, and a steady-state optimization algorithm assisted by the PT model was adopted to robustly solve the optimization problem. The optimization results of either ethylene glycol RD or methyl acetate RD demonstrated that assuming all the liquid hold-up of a stage belonged to the tray will cause significant deviations in the column diameter, weir height, and the number of stages, which leads to not meeting the separation requirements and even operation hydraulic infeasibility. The rigorous model proposed in this study which considers the liquid hold-up both on trays and in downcomers as well as hydraulic constraints can be applied to systematically design industrial RD plate columns to simultaneously obtain optimal operating variables and equipment structure variables.

Optimalisasi Desain Struktur Gedung Interdisciplinary Engineering (IDE) – Fakultas Teknik Universitas Indonesia dengan Memanfaatkan BIM (Building Information Modelling)

Project design is a step in the construction process that determines the technical requirements to be applied when the project is constructed. BIM (Building Information Modeling) is a form of technological innovation used in project design. BIM (Building Information Modeling) has become the main factor for increasing efficiency and accuracy; using BIM, everything related to design, construction, scheduling, and costs can be integrated into one digital platform that all stakeholders can access. In this paper, the structural planning optimization of the Interdisciplinary Engineering (IDE) Building - Faculty of Engineering, University of Indonesia, will be carried out. This building planning refers to (SNI-2847-2019) concerning Structural Concrete Requirements for Buildings and (SNI-1726-2019) concerning Procedures for Planning for Earthquake Resistance of Structures. Outputs are generated through superstructure and substructure plans, the design of foundation structures, columns, beams, and plates, 2D Detail Engineering Design (DED), 3D modeling, and construction management plans in the form of Budget Plans and scheduling.

Optimal Design of Shear Wall Sections Considering Different Stress-Strain Relationships of Steel According to Eurocode 2

The present paper highlights the usefulness of bi-linear stress strain relationship of steel with inclined plastic branch with respect to horizontal plastic branch for slender rectangular shear wall design. The inclined branch refers to strain hardening of steel for which, stresses also increase with strain beyond the yield point. This significantly complicates the solution process for load-based design approach as adopted in flexure design. For design of sections subjected to axial forces with flexure, capacity-based approach of design is adopted instead of load-based design. Hence, the myth that the inclined plastic planch will lead to cumbersome and tedious calculations does not seems to hold good for capacity-based design approach which is adopted for design of columns and shear walls. In the present paper using different strength classes of concrete as permitted by the latest version of Eurocode2 (2023) and strength of steel, fyk= 500 MPa along with different ductility classes have been used for the development of P-M interaction charts for rectangular shear walls with uniformly distributed vertical reinforcements. An average of 12.26% and 3.42% increment in moment capacity values have been obtained in under reinforced and over reinforced failure conditions respectively between charts prepared by inclined and horizontal plastic branch.

Quantitative assessment of the 3D pore space and microglobule clustering network to understand chromatographic transport phenomena in polymeric monolithic columns

The 3D pore space and microglobule clustering network of polymer monolithic columns, which exhibited similar external porosity but significantly different chromatographic dispersion and permeability characteristics, were subjected to tomographic imaging followed by stereological analyses. The morphologies of the monolithic support structures were examined using serial-block-face scanning electron microscopy. The statistically computed characteristic chord-length, hydraulic radius and tortuosity of the pore are strongly associated to chromatographic transport processes, in particular, eddy dispersion and mass-transfer resistance contributing to chromatographic dispersion, and permeability of monolithic columns. Moreover, Giddings’ trans-column velocity bias has been quantified in monoliths for the first time. With demonstrated method robustness, the proposed morphological descriptors and the streamlined analysis workflow provide novel insights bridging the structure-performance relationship for future chromatography column design.

A sandwich-type Winkler-Pasternak double elastic foundation beam model for analysis of nut column load transfer systems of shiplifts

The rack and pinion shiflifts feature its capability of fortification against extreme accidents of unbalance of ship chamber. This requires the load transfer systems of nut columns to be able to transfer the huge and centralized loads from the safety mechanisms to the tower columns in a distributive bearing way. Aiming at exploring a design-oriented computation method for the nut column load transfer systems (NCLTSs), a sandwich-type semi-infinite coupling Winkler-Pasternak double elastic foundation beam model (DEFBM) has been established, with a distributive assumption of the axial constrain force on the interfaces between the nut columns, mortar beds, adjusting beams and the second stage concrete based on the physical model test, has been proposed. A set of formulars for describing the distribution of deflections, internal forces and stress of nut columns and adjusting beams have been derived. A case study of the Three-Gorges shiplift has been conducted to demonstrate the approach of calculation of internal forces and stress by applying the formulas based on sandwich-type Winkler-Pasternak DEFBM, showing the convenience and rationality of the method to parametric layout design of the nut columns and adjusting beams in NCLTSs. Not only to NCLTSs and rack load transfer systems of shiplifts, the sandwich-type Winkler-Pasternak DEFBM also supplies the reference to the modeling and analysis of the rail-embedment structural systems broadly applied in hydraulic engineering.

Behavior of CFRP confined rectangular high-strength concrete-filled steel tubular columns under eccentric compression

This paper presents an experimental study on the eccentric compression behavior of rectangular high-strength concrete-filled steel tubular columns confined with carbon fiber reinforced polymer (CFRP- CFST). Seventeen specimens were tested under eccentric compression, examining key parameters involving eccentricity, number of transverse CFRP layers, slenderness ratio, corner radius, CFRP partial wrapping scheme, and CFRP orientation. The effects of these parameters on failure mode, load-displacement relationship, strain development, and ultimate mechanical properties were analyzed and discussed. The ultimate bearing capacity (Nu) of CFRP-CFST columns improved with an increase in transverse CFRP layers, corner radius, and CFRP wrapping proportion, while it decreased with increasing eccentricity and slenderness ratio. Partial wrapping schemes reduced the effectiveness of CFRP confinement, with the outward local buckling of the steel tube primarily occurring in areas without CFRP confinement. Longitudinal CFRP provided less improvement to Nu compared to transverse CFRP under small eccentricity conditions. A theoretical model based on the fiber element method was developed to predict the ultimate bearing capacity and implemented through a custom program to facilitate calculations. The model was validated using a test database comprising results from this study and previous research. Additionally, axial force-bending moment (N-M) interaction curves were rapidly generated, providing a theoretical basis for the design and practical application of CFRP-CFST columns in practical engineering.

Synergistic integration of zeolite engineering and fixed-bed column design for enhanced biogas upgrading: Adsorbent synthesis, CO2/CH4 separation kinetics, and regeneration assessment

Biogas, a renewable energy vector derived from anaerobic digestion of organic waste, requires CO2 separation to enhance its calorific value for engine fuel. This study integrates CO2/CH4 separation in biogas using a novel approach integrating dual chemically-activated zeolites and fixed-bed column purification. Biogas produced via CSTR/ultrafiltration (69 % CH4, 30 % CO2, 14 ppm H2S) was further upgraded using HCl + NaOH and H2SO4 + NaOH activated zeolites. Optimal absorption capacity of 97.77 ± 0.01 % was achieved at 140 mesh, 60-minute H2SO4 + NaOH activation, 2-hour calcination (400 °C), and 200 mL/min flow rate. Breakthrough was observed at 18.12 min. Langmuir isotherm (R2 = 0.9992) and Elovich kinetics (R2 = 0.9846) best described the adsorption process. XRD analysis showed significant crystal size reduction post-activation (53.31 nm to 16.90 nm). Notably, BET analysis revealed enhanced surface properties surface area of 286.71 m2/g, pore volume of 0.213 cc/g, and pore diameter of 3.532 Å. An innovative dual-column system with non-isothermal TSA protocol optimized CO2 adsorption (30 mins) and desorption (17 mins, 40 °C, 100 mL/min), yielding superior near-pure methane biogas (99.29 % CH4, 0.66 % CO2, trace H2S). A methane loss of 2.75 % during upgrading demonstrated high CO2 selectivity. This synergistic approach presents a promising solution for sustainable biogas purification and engine fuel applications.

3D-printed thermally expanded monolithic foam for solid-phase extraction of multiple trace metals.

Digital light processing (DLP) 3DP, commercial acrylate-based photocurable resins, and thermally expandable microspheres-incorporated flexible photocurable resins were employedto fabricate an SPE column with athermally expanded monolithic foam for extracting Mn, Co, Ni, Cu, Zn, Cd, and Pb ions prior to the determination using inductively coupled plasma mass spectrometry. After optimizationofthe thermally activated foaming, the design and fabrication of the SPE column, and the automatic analytical system, the DLP 3D-printed SPE column with the thermally expanded monolithic foam extracted the metal ions with up to 14.8-fold enhancement (relative to that without incorporating the microspheres), with absolute extraction efficiencies all higher than 95.6%, and method detection limits in the range from 0.5 to 5.2ng L-1. We validated the reliability and applicability of this method by determination ofthe metal ions in several reference materials (CASS-4, SLRS-5, 1643f, and Seronorm Trace Elements Urine L-2) and spikedseawater, river water, ground water, and human urine samples. Theresults illustrated that to incorporate the thermally expandable microspheres into the photocurable resins with a post-printing heating treatment enabled the DLP 3D-printed thermally expanded monolithic foam to substantially improve the extraction of the metal ions, thereby extending the applicability of SPE devices fabricated by vat photopolymerization 3DP techniques.

Global buckling behaviour and design of cold-formed steel octagonal hollow section columns under compression

This paper experimentally and numerically investigated the global buckling behaviour of cold-formed steel octagonal hollow section columns. A test programme was first conducted on 10 OctHS steel columns made of Q460 and Q690 high strength steels. Each steel grade comprised five specimens with distinct geometric dimensions. Material properties and initial global imperfection were measured and are reported herein. Axial load versus mid-height lateral deflection curves, axial load versus axial strain curves, and failure modes of OctHS specimens are presented and discussed. In conjunction with laboratory works, finite element models were subsequently developed to replicate the load-deformation responses and failure modes of OctHS columns against the experimental results. Following the validation of proposed numerical modelling technique, extensive parametric studies were performed to evaluate the effects of steel grade, cross-section slenderness, member slenderness, and initial global imperfection. Furthermore, results from 10 test specimens and 608 numerical models were used to comprehensively assess the applicability of current codes of practice on the design of OctHS long columns. Modifications and design recommendations were proposed based on the assessment results. Corresponding reliability analyses were also performed for each design method.

Fire Resistance Performance of Constrained H-Shaped Steel Columns with Uneven Vertical Temperature Distributions

Steel columns, which are widely used in building frameworks and spatial structures, are susceptible to capacity degradation during fires, potentially leading to the overall collapse of buildings. Existing research on the fire resistance of steel columns assumes that the temperature loads encountered by steel columns are evenly distributed vertically. However, real-world fire scenarios often feature significant vertical temperature differences. Therefore, this study comprehensively investigated these variations to derive a temperature curve that accurately represents real fire conditions. Subsequently, the fire resistance limits of steel columns were studied using this temperature curve, leading to a revised calculation formula for the critical fire resistance temperatures of steel columns. The following conclusions were drawn: (1) Nonuniform longitudinal temperature distributions are influenced by parameters such as the fire source distance, the heights of ventilation openings, and the distance between a vent and the temperature measurement point. Among them, the fire source distance has the greatest impact, with the maximum longitudinal temperature difference reaching over 500 °C. (2) Variations in the load ratio and longitudinal temperature differences alter the failure positions of steel columns, reducing their critical temperatures by up to 200 °C. (3) The revised critical fire resistance temperature formula is more accurate and safer compared with that outlined in the “Technical Code for Fire Protection of Steel Structures” (GB51249-2017). These findings offer valuable insights for the fire designs of steel columns.