Plastic Columns Research Articles

Plastic Transport in Rivers: Bridging the Gap Between Surface and Water Column

Rivers act as an important transportation pathway for land-based plastic litter to the ocean. Recently, rivers have also been identified as potential sinks and reservoirs for plastics. Knowledge of plastic transport over different depth profiles in rivers remains limited. In this study, we evaluated the vertical distribution of macro- and mesoplastics, using a larvae net and a trawl net in the river Rhine and its two major branches, i.e. Waal and IJssel. Subsequently, to estimate the relationship between the surface transport of plastic items, i.e., floating items, compared to the transport in deeper layers in the water column, including suspended and bed-transported plastic, an extrapolation factor was derived per day for the middle and bottom nets divided by those found in the surface net. The observed macro- and mesoplastic OSPAR categories collected in different layers in the water column were rather consistent between different sampling techniques. Fragments of soft mesoplastic falling under the category “Plastic film plastics 0-2.5 cm (soft)" were recorded most frequently in the investigated rivers with our monitoring techniques. During larvae net monitoring, hard plastics were more frequently found at the river surface than at the middle or bottom of the river for both macroplastic and mesoplastics, while soft plastics were more frequently detected near the bottom. For larvae net monitoring, the extrapolation factor, reflecting the concentration ratio of macroplastic items transport at different depths, i.e., from the surface downwards to the middle and the bottom ranged between 0.38 to 2.2 and 0.36 to 5.7, respectively. The extrapolation factor of mesoplastic transport from the surface downwards to the middle and the bottom ranged between 0.70 to 1.84 and 0.69 to 2.57. During trawl net monitoring, the extrapolation factor, reflecting the concentration ratio, for macroplastic ranged between 0.82 – 1.30, and for mesoplastic between 0.52 – 1.40. Overall, the findings of this study show that estimates of plastic concentrations solely based on surface transport could result in an under- or overestimation of riverine plastic transport.

A theoretical model and verification of soil column deformation under impact load based on the Duncan-Chang model

The dynamic compaction method has been widely adopted in foundation treatment to densify the soil fillers. However, for the complexity of the impact behavior and soil mechanical properties, the theoretical research of dynamic compaction lags behind its practice for complex soil properties and stress paths. This paper presents a theoretical model applied to describe soil column plastic deformation under impact load. The relationship among stress increment, strain increment, and plastic wave velocity was derived from the aspect of propagation characteristics of stress waves in soil first. Combined with the Duncan-Chang Model, a one-dimensional theoretical model was established then. A numerical model was developed further to check the performance of the model. It showed that the deformation at the end of the soil column was mushroom-shaped. Both the axial and lateral deformation increased with the impact velocity. While some particles located at the side of the soil column end may splash under repeated impact. The theoretical deformations of the soil column were consistent with the experimental results both in the direction of axial and lateral.

The strain demand of reinforced concrete bridge columns under seismic loading

The steel in reinforced concrete (RC) members that form plastic hinges must possess sufficient strain capacity to dissipate seismic deformation demands. Unfortunately, there is limited information on the seismic strain demands of bridge column plastic hinges. Instead, designers rely on a perception of cyclic strain capacity that is an approximate rule of thumb. A standard methodology needs to be established for quantifying the strain demand on these structural members as a function of the expected seismic hazard. To develop this methodology, 1944 columns were analyzed with nonlinear time-history analyses (NLTHAs) using ground motions from a range of earthquakes. This study evaluates the strain demand on RC bridge columns by defining the relationship between the strain demand and earthquake intensity. The results of the model are defined in terms of the peak tensile strain of the reinforcing bar, [Formula: see text]. The earthquake intensity with the highest correlation to the [Formula: see text] was determined to be the elastic spectral displacement at the optimal period ([Formula: see text]), which is defined as 75% of the effective period. The relationship between [Formula: see text] and [Formula: see text] can be used to predict the strain demand for an RC bridge column at a given geographic location. Results are presented as a probability density function (PDF), representing strain demand, compared to a PDF of the column capacity. The intersection of the capacity curve and demand curve represents the maximum acceptable strain given as a function of [Formula: see text]. This methodology can help understand the demand placed on a structural system given a region’s seismicity.

Influence of peatmoss and polymer on moisture characteristic curve of soils with different gypsum and clay contents

To determine the hydraulic properties of several soils with varying clay and gypsum contents and treatments with peat moss and polymer, a laboratory experiment was done. Gypsum ratios varied from 410 g kg-1 to 46 g kg-1, while clay ratios ranged from 0 to 435 g kg-1. Two soils were employed, one having 410 g kg-1 of gypsum and the other containing 435 g kg-1 of clay. Peat moss and a polymer were used to treat the five soils. Three soaking and drying cycles were performed on soil that had been treated with conditioners by packing it into plastic columns that were 5 cm in diameter and 25 cm high with a bulk density of 1.3 mcg m3. The experiment's goal was to improve the ability of gypsiferous soils to retain water. The moisture characteristic curves were computed using the connection between the volumetric moisture content () and the matric tension, which ranged between 0.1 and 1500 kPa. The results revealed that the values of for the study's soil and treatment methods decreased as matric tension increased, and the discrepancies were more pronounced at low tensions. With rising gypsum and falling clay, the values of decreased. As gypsum was raised from 46 to 410 g kg-1, the values of the available water reduced from 0.276 cm3 cm-3 to 0.191 cm3 cm-3. The addition of peat moss (1%), polymer 1 (2%), and a combination of the two clearly increased the amount of water that was accessible while also changing the amounts of clay and gypsum in all treatments.

Properties of steel fiber reinforced mortar‐plastic columns with the cross‐section in a form of a Cesaro fractal

AbstractIn this paper, the concept of steel fiber reinforced concrete (SFRC)‐plastic columns was explored and discussed. Plastic served as a 3D printed formwork that remained in place. Five different column cross‐section shapes, based on Cesaro fractal iterations, were created and filled with steel fiber reinforced mortar. After curing, the specimens were loaded and load‐strain characteristics were recorded, with a focus on destruction characteristics and energy dissipated up to 6.0% strain. The results showed that columns with fractal‐based cross‐sections had smooth destruction with significant formwork deformation. All columns exhibited highly quasi‐plastic behavior. The results demonstrate the feasibility of replacing traditional formwork and concrete with a more automated 3D printed plastic and SFRC solution. Future research should focus on large‐scale columns and other structural elements.

Exploring the Potential of 3D Printing Technology for Sustainable Plastic Roads: A Preliminary Investigation

The urgency of climate change has highlighted the need for sustainable road construction materials, replacing the conventional asphalt, which significantly contributes to global warming and the urban heat island effect. With this in mind, the construction of the world’s first 30-m plastic road in Zwolle, Netherlands, in 2018, opened the door for novel plastic applications as paving materials. However, its application is currently still limited to sidewalks and light-load cycling lanes. The feasibility of utilizing 3D printing technology to provide the necessary structural design flexibility for the production of plastic pavement modules that can withstand heavy traffic and extreme weather conditions was examined in this preliminary study. The suitability of six plastic materials (PLA, PETG, ABS, TPU, Nylon, and polycarbonate) for 3D printing was evaluated. Polylactic acid (PLA), and polyethylene terephthalate glycol (PETG) were identified as the most suitable materials for this study. Three small-scale structural systems, namely hollow modular with plastic columns, hollow modular with solid plastic cones, and hollow modular with X-bracing, were designed and successfully printed using the adopted materials and a 3D printer. The developed systems were subsequently subjected to compression testing to assess their structural performance under heavy traffic loads and demonstrate the feasibility of the concept. The results showed that the PLA conic structural system was effective and exhibited the highest compression strength, while the PETG conic system exhibited ductile behavior with superior thermal stability. The study suggests that the hybrid system of PLA and PETG materials may improve the overall performance, combine flexibility and strength, and potentially improve the resistance to extreme weather and heavy traffic. These findings prove that 3D printing technology has the potential to revolutionize the road construction industry and provide more sustainable solutions for infrastructure development.

Cyclic performance welded steel reduced beam section moment connections using longitudinal slots in flanges

A new type of steel reduced beam section connection using longitudinal slots in the beam flanges is introduced. The effect of different parameters has been studied by the non-linear three-dimensional finite element method. Parameters have been the distance between the slot and column face, the length and width of the slot, the distance between the slot and the edge of the beam flange, the number of slots, the distance between slots, and the dimensions of the beam. The displacement controlled cyclic loading protocol recommended by SAC has been imposed. The von Mises yield criterion has been used. Obtained results show that creating the slots in the beam flange improves considerably the performance of the connection. The bending moment at the column face and plastic strains in the weld decrease by 32% and 94%, respectively, by increasing the slot length by 264%. The bending moment and dissipated energy reduce by 59% and 66%, respectively, when the slot width is increased by 430%. By increasing the length and width of the slot from a specific value and by moving the slot towards the beam web, the behaviour of the connection becomes unsatisfactory. The effect of the beam height is more than that of other dimensions of the beam. Based on the results obtained, recommendations for the design implications related to the geometric dimensions of the slots have been formulated.

Mechanistic study of ultrasound-assisted chromatography using plastic and stainless steel columns

Based on the previous ultrasound-assisted chromatography (UAC) studies on plastic and stainless steel (SS) columns, this study explores the UAC mechanism by comparatively analyzing ultrasound effects on plastic and SS columns with C18 stationary phase when separating a mixture of polycyclic aromatic hydrocarbons (PAHs) under various ultrasound intensities. The results showed a substantial difference in H values between the PEEK and SS columns under the influence of ultrasound agitation. Specifically, for the pyrene peak, as the ultrasonic intensity increased from 0% to 100% of 900 W, the H values of the SS column slightly rose from 8.82 μm to 9.86 μm. Conversely, the corresponding values for the PEEK column exhibited a significant 12-fold increase from 11.5 μm to 134 μm. The findings demonstrated poor penetration of ultrasound energy through the SS column, and the temperature rise of the medium induced by the ultrasound was the primary contributing factor to PAH separation. However, ultrasound easily penetrated through the plastic column, resulting in acoustic cavitation within the C18 polyether ether ketone (PEEK) column. Cavitation induced heat generation and contributed to a decrease in retention time and the magnitude of peak broadening or distortion, depending on the specific ultrasonic energy. Based on the estimated change in inlet temperature of the PEEK column due to an acoustic effect, the comparison with temperature effects under non-sonic conditions consistently demonstrated a stronger acoustic effect in reducing the retention time, by 2–9%, depending on specific peaks and pairs. We revisited the previously described separation mechanism of ultrasound-assisted ion chromatography and conjoined with our findings to infer and establish a thorough explanation for the previously unexplained separation mechanism of chiral separation and size exclusion chromatography by UAC using SS columns.

Material nonlinearities yield doubly negative holey metamaterials

Mechanical metamaterials with negative stiffness and negative Poisson’s ratio are exciting prospects for advanced material design. A plastic column with a series of periodically-spaced holes exhibits both of these properties when buckled under compression. In this paper, the behaviour of such a column under compression is measured experimentally and described with a simple mathematical model. This model predicts the compression, buckling and post-buckling behaviour of the entire column from the mechanical response of the thin ligaments of material that form the column’s microarchitecture to compression, rotation and shear forces, which are characterised experimentally, The softening behaviour in holey columns beyond the critical level of compression for pattern transformation is shown to be due to material constitutive nonlinearities in the rotation and shear response of the microarchitecture. Geometric perturbations to the columns can cause the observed pattern to change, but result in approximately the same force–displacement measurements as for the column with perfect geometry. This approach provides a useful framework to study systems where both geometric and material nonlinearities underpin observed phenomena.

Axial Compressive Properties of Fiber-Reinforced Polymer-High-Water Material-Polyvinyl Chloride Plastic Double-Wall Hollow Column.

To further enrich the side-filling structure system of goaf-retaining roadways and explore the compression reaction mechanism of the composite in the support environment of underground mine roadways, this paper introduces a double-wall hollow composite pier structure (FPRSC structure) that is composed of the fiber-reinforced polymer (FRP) composite and polyvinyl chloride plastic (PVC) as restraint materials and the infill material featured with a high water-to-powder ratio. A total of 16 circular specimens with a diameter and height of 100 mm were tested to explore the axial performance of the combined support structure. The main control variables in the present research included the water-to-cement ratio of the high-water material (e.g., 2:1, 3:1, and 4:1), the thickness of the FRP pipe (i.e., 6 mm and 3 mm), the inner diameter of the PVC pipe (i.e., 29 mm and 22 mm), as well as the thickness of the PVC pipe (1.5 mm and 5 mm). Test results showed that the high-water material was under triaxial stress due to the double-wall tube binding, and the bearing capacity of the composite was higher than that of the single material. Meanwhile, the FPRSC structure exhibited obvious strain-hardening characteristics when the infill material is under the combined constraints of double-wall hollow tubes. Moreover, the ratio of PVC-c, FRP-A, and high-water material with a water-cement ratio of 3:1 shows the best axial mechanical properties. The new composite pier structure with high toughness and strength has wide application prospects in the field of goaf retention in deep underground mines.

Effects of structural size and confinement on CFST column plastic hinge length

The objectives of this work are to study the influence of structural size on the plastic hinge length of square concrete-filled steel tubular (CFST) columns and to discover the influence of confinement generated by steel tubes on the plastic hinge length. A total of 24 square CFST columns were designed and tested with different column widths (i.e., 200 mm ∼ 800 mm) and different confinement effects (described by width-to-thickness ratio, i.e., 50, 80 and 100). The failure behavior and the curvature distributions of the tested columns subjected to axial compression loads and horizontal cycling loads were reported, and the corresponding plastic hinge lengths of the columns were obtained. The test results indicate that, as the column width increases, the plastic hinge length increases linearly, about 0.6– 0.9 times the column cross-sectional widths. Also, as the confinement effect increases, namely, the magnitude of the width-to-thickness ratio decreases, the plastic hinge length decreases slightly. Moreover, the non-dimensional plastic hinge length, defined as the ratio of plastic hinge length and column width, was proposed. The non-dimensional plastic hinge length decreases with increasing the column width, showing a significant size effect. An empirical formula for predicting the magnitude of the plastic hinge length of CFST columns was established.

TRANSPORTATION OF SPOROSARCINA PASTEURII IN POROUS MEDIA WITH DIFFERENT PARTICLE SIZES

The current study aimed to determine the transportation distance of Sporosarcina pasteurii (ATCC 11859) and the number of cells present in porous media. The experiments were carried out in continuous-flow columns, which were plastic columns with an inner diameter of 2.4 cm and a height of 50 cm, and which contained glass beads with average diameters of 0.25 mm, 0.50 mm and 1 mm to mimic porous media. To investigate cell transport through columns, suspension of Sporosarcina pasteurii was introduced into columns at a flow rate of 2 mL/min and the cell densities of OD600 0.15, 0.75, 2.25. To count the bacteria in each section, the column was divided into five equal parts. The results showed that the most cells, which were counted as 1.72*1010 cells, were deposited in the columns packed with 0.25 mm glass beads for the experiments with OD600 2.25, while the deposited cell number decreased at the bottom of the column. The cell deposition was greater at the bottom of the column in the case of columns packed with 1 mm glass beads. According to the findings, while using smaller glass beads resulted in more cell deposition in the porous media, using larger glass beads resulted in more cell transport through the porous media. It can be concluded that larger particle sizes may result in easier transportation conditions for cells transporting deep into porous media.

Application of modified partial capacity design on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations

Modified Partial Capacity Design (M-PCD) is an alternative design method for seismic-resistant structures. M-PCD adopts the partial side sway mechanism for its failure mechanism where beams and some columns are allowed to develop plastic hinges. This method uses two models for design. The first model simulates a small earthquake occurrence and is used to design beams and plastic columns. The second model simulates a larger earthquake occurrence and damages on the structure. The elastic columns are designed based on the superposition of internal forces from the first and second models, provided that the effects from gravity loads are considered only once. This study focuses on the application of M-PCD on six-story L-shaped reinforced concrete buildings with variations on elastic columns configurations. Nonlinear time history analyses are used to determine the buildings’ performance on two earthquake levels (EDRS and MCER) and two earthquake directions (0° and 45° rotated earthquake). The results show that the partial side sway mechanism is observed in most of the analyzed structures and drifts are within set boundaries.

Performance of olive mill wastewater treatment using hybrid system combining sand filtration and vertical flow constructed wetlands

Olive mill wastewater (OMWW) is a main source of noxious and recalcitrant organic pollutants of significant concern in environmental engineering. For this purpose, the current study assessed the performance of system combining sand filtration and vertical flow constructed wetlands (VF-CWs) in reducing the organic load of OMWW. Sand filter system wed in this study is composed of 6 plastic columns of 0.50 m in diameter and 120 L of capacity. The irrigation of sand filter columns was assured by 50 % diluted OMWW at flow rate of 5 L/day. VF-CWs system consists of a 1 m3 tank filled with soil and gravel in the bottom and planted of Typha latifolia, Phragmites australis and Arundo donax aquatic plants. The irrigation of VF-CWs system was assured with treated OMWW with a flow rate of 20 L twice in the week. Obtained results showed that sand filtration achieved a high removal rate of 76.42, 75.12, 79.7 and 78.10 %, respectively, for total suspended solid (TSS), dissolved COD (chemical oxygen demand), total COD and phenolic compounds. The usage of the combination of sand filter and VF-CWS improved significantly the elimination efficiency of total COD up to 91.44 %, dissolved COD up to 77.09 % and phenolic compounds up to 79.47 %, but it did not report any performance in the removal of TSS. Despite the high performance of hybrid system (sand filter+VF-CWs) in reducing the organic pollution, final effluent concentrations remained below the permitted limits for discharge into a municipal sewer system.

INSPECT-SPSW: INelastic Seismic Performance Evaluation Computational Tool for Steel Plate Shear Wall Modeling in OpenSees

Modeling Steel Plate Shear Wall (SPSW) behavior can be computationally demanding. This is especially true when high-fidelity modeling is carried out via shell or 3D solid elements. It has been shown that SPSW behavior can be captured with adequate accuracy through the strip method via nonlinear truss elements idealization. The widely accepted and reliable analysis platform, OpenSees, requires text-based input (.tcl) files created by a skilled programmer. Hence, a Pre/Post-processing User Interface (UI) software package (INSPECT-SPSW) is introduced herein. With basic input, the INSPECT-SPSW package allows the user to create the OpenSees (.tcl) input file, run different nonlinear analyses, and retrieve and visualize the output. In addition, the UI includes illustrated wrappers for several OpenSees commands for various material definitions, plasticity modeling options, modal analysis, and nonlinear analysis types. Validation and verification were conducted against published results of experimental and numerical cyclic loading specimens. The user-friendly interface successfully created accurate models that capture the SPSW nonlinear behavior, including the various possible failure mechanisms. e.g., beam or column plastic hinging, web plate yielding, etc. With demonstrated performance and intuitive UI, INSPECT-SPSW is expected to facilitate the broad adoption of the strip method for Performance-Based Earthquake Design (PBED) of SPSWs.

Effect of Different Soil Organic Carbon Content in Different Soils on Water Holding Capacity and Soil Health

An experiment was carried out to study the effect of soil organic carbon (SOC) and soil texture on the distance of the wetting front, cumulative water infiltration (I), infiltration rate (IR), saturated water conductivity (Ks), and water holding capacity (WHC). Three levels ( 0, 10, 20, and 30 g OC kg-1 ) from organic carbon (OC) were mixed with different soil materials sandy, loam, and clay texture soils. Field capacity (FC) and permanent wilting point (PWP) were estimated. Soil materials were placed in transparent plastic columns(12 cm soil column ), and water infiltration(I) was measured as a function of time, the distance of the wetting front and Ks. Results showed that advance wetting front as a function of time for soil column was 6 minutes and with no differences between OC levels for sandy soils, while it ranged between 90 minutes (0% OC) - 130 minutes (3% OC) for loam soils, and between 470 minutes (0 %OC) and 590 minutes (1%OC) for clay soils, at the same time cumulative water infiltration(I) increases at the beginning of infiltration and decreases with time and levels of OC. The highest infiltration values were in sandy soils, giving data of 0.05 and 0.12 cm min-1, with no significant differences with OC rates. IR values decreased when OC increased in loam soils, and IR increased exponentially in clay soils with increasing OC levels. The values of Ks decrease with increasing OC for sandy and loam soils, and increase when OC increases above 3% for clay soils. FC and WP values were increased for sandy, loam and clay soils when OC was increased. The AW values decreased for both sandy and clay soils compared to loam soils. It can be concluded that AW can be estimated from FC values regardless of texture and OC by the linear function: AW=0.51(FC)+0.005.

State-of-art summary of the strength hierarchy assessment and its applications

Strength hierarchy assessment is a method developed to be able to identify the governing failure mechanisms at reinforced concrete (RC) beam-column joints. The main failures that can be identified in this method are: i) beam plastic hinge; ii) column plastic hinge/shear failure; iii) beam-column joint shear failure. Through the identification of the governing failure mode in a joint, the validity of the capacity design principles can be checked for the considered RC beam-column joint. The obtained observations can then be used in finding the most optimal repair/strengthening application. This method has been going through updates and developments in the last decade and new applications have emerged. In this article, a state-of-the-art summary of the procedure is reported with its most recent updates as well as its practical engineering applications.

Leachate characteristics, dry matter yield of Urochloa decumbens and properties of two contrasting soils irrigated with sludgewater in columns

AbstractIncreasing demands on freshwater and challenges in disposal of wastewaters encourage their use for irrigation. The study evaluated the effects of irrigation of signal grass (Urochloa decumbens) with sludgewater on leaching, uptake and retention of a range of elements in two contrasting soils in columns. The grass was grown on a sandy loam and a clay soil packed in plastic columns and irrigated for 119 days with either undiluted, diluted sludgewater or tap water. The sludgewater had a pH of 6.9 and high aluminum (Al), manganese (Mn), iron (Fe), and boron (B). Analyses were conducted on leachates, above‐ground plant biomass (two harvests), and soils at the end of the experiment. Sludgewater treatments increased grass biomass yield and uptake of nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) in both soils with a greater nutrient uptake from the clay than the sandy loam. The application of sludgewater increased Mn and reduced P (sandy loam only) in the leachate with no effects on Al, Fe, or B. Uptake of Al, Fe, and B was increased by sludgewater application. Even when diluted, the sludgewater increased extractable Mn, particularly in the clay soil. The findings showed that irrigation of the soils with sludgewater increased Mn and B concentrations and uptake by signal grass, with no negative effects on biomass production. Leaching and accumulation in the soils of toxic elements were minimal in the short term. Sludgewater can therefore be used to grow signal grass in both soils although these effects need to be evaluated under field conditions.

Outdoor Inclined Plastic Column Photobioreactor: Growth, and Biochemicals Response of Arthrospira platensis Culture on Daily Solar Irradiance in a Tropical Place.

Implementation of outdoor photobioreactors has been challenged by an extremely oversaturated daily peak of solar irradiance. This study aims to understand the role of column size and paranet shading as well as to investigate the most convenient light control in outdoor cyanobacterial culture. The photobioreactor (PBR) consisted of plastic columns with a diameter of 12.74 cm (PBRd-20) and 31.85 cm (PBRd-50) laid outdoors and inclined at 158.22° upwards against solar radiation, while paranet shading was provided at 0%, 50%, 70%, and 90% shading capacity. A semi-continuous culture of cyanobacterium Arthrospira (Spirulina) platensis was conducted for 6 weeks with weekly monitoring of the growth parameter as well as the proximate and pigments content, while the daily irradiance and culture maximum temperature were recorded. The result shows that the column diameter of 12.74 cm had a lethal risk of 44.7% and this decreased to 10.5% by widening the column diameter to 31.85 cm. This lethal risk can be eliminated by the application of a paranet at a 50% reduction level for the column diameter of 31.85 cm and a 70% reduction level for the column diameter of 12.74 cm. The highest culture productivity of 149.03 mg/(L·day) was achieved with a PBRd-20 with 50% shading treatment, but a PBRd-50 with 90% shading treatment led to an increase in the protein and phycocyanin content by 66.7% and 14.91%, respectively.

Effect of boundary condition on the cyclic response of I‐shaped steel columns: Two‐story subassemblage versus isolated column tests

AbstractRecent studies on isolated steel columns under combined axial load and cyclic lateral drift showed that the column response is affected by the boundary condition. To consider more realistic boundary conditions of first‐story columns in a frame, two‐and‐a‐half story beam‐column subassemblages were tested to investigate their behavior under reversed cyclic loading. The subassemblages, composed of a steel column with steel beams at two floor levels, used highly ductile I‐shaped sections with web slenderness of either 37 or 49. Two isolated fixed‐fixed columns were tested to facilitate a direct comparison with the subassemblage testing. An axial compression force corresponding to 20% of the yield force was applied. Test results showed that the realistic boundary condition at the top end of the first‐story column significantly alters the column plastic hinging, moment distribution, and out‐of‐plane deformation reported previously based on isolated column testing. Plastic hinging of the adjoining beams caused the inflection point of the first‐story column to move upward initially, then moved downward when plastic hinging developed at the column base. Out‐of‐plane deformation observed from isolated columns did not occur in the subassemblage column because hinging did not occur at the top end. Plastic components of the backbone curves for both the subassemblage column and isolated column were very similar; the former delivered a larger story drift angle rotation due to a larger yield rotation, dependent on the elastic lateral stiffness of the column. A closed‐form solution that calculates this stiffness for any boundary condition was developed and verified from test results.