Vertical Elements Research Articles

Making Quick-Build Sidewalk Extensions Accessible to Pedestrians with Vision Disabilities

Quick-build sidewalk extensions that shorten crossing distances and improve visibility between drivers and pedestrians waiting to cross the street are understood by most travelers, but wayfinding is difficult for pedestrians with vision disabilities who are unlikely to know they exist without specific familiarization. This research evaluated the effectiveness of three potential treatments for mitigating these wayfinding problems, all of which resulted in improvements in measures of wayfinding: 1) removing the detectable warning surface (DWS) from the curb ramp and installing DWS across the width of the crosswalk at the perimeter of the sidewalk extension; 2) placing a 24-inch wide strip of raised-bar tactile direction indicators with bars oriented perpendicular to the crossing direction along one side of the curb ramp and extending through the sidewalk extension to the DWS at the perimeter; and 3) placing trapezoidal tactile warning delineators (TWDs) along the edges of the crosswalk, within the sidewalk extension, to delineate the pedestrian path. A combination of moving the DWS and installing TWDs along crosswalk edges resulted in the most accurate and effective wayfinding to and through the quick-build sidewalk extension. The spacing of vertical perimeter elements (e.g., flexible posts) to ensure they were detectable by pedestrians with vision disabilities was also evaluated. Participants who traveled outside the crosswalk reliably encountered and detected at least one vertical perimeter element when the maximum separation between vertical elements was 24 inches. The perimeter was not reliably encountered and detected when the separation between vertical elements was considerably greater.

Exploring the influence of body movements on spatial perception in landscape and interior design

This study investigates the influence of body movements on spatial perception in both landscape and interior design environments, focusing on how physical interactions shape spatial understanding beyond visual perception alone. Grounded in the theory of embodied cognition, the research examines how gait, posture, and movement dynamics affect spatial awareness. The study captures detailed data on movement patterns and visual engagement across different spatial contexts using a combination of real-world observations and Virtual Reality (VR) simulations, motion-tracking systems, wearable sensors, and eye-tracking technology. A total of 157 participants, aged 20 to 65, navigated both outdoor landscapes and indoor environments, with key variables such as surface materials, spatial layout, and lighting conditions manipulated to assess their effects on spatial perception. The study measured gait speed, step frequency, path deviations, time to destination, visual attention, and subjective ratings of perceived openness, ease of movement, and emotional response. Key findings include that surface materials significantly influenced gait speed and step frequency. For example, participants walking on concrete had a significantly faster gait speed (mean difference = 0.5220, p = 0.001) than those walking on gravel. In terms of spatial layout, the two-way Analysis of variance (ANOVA) results showed that winding paths led to more path deviations (F-statistic = 350.00, p = 3.19 × 10−8) and longer times to destination (F-statistic = 1744.00, p = 2.39 ´ 10−11) compared to straight paths. The environment type (landscape vs. interior) also significantly affected navigation, with landscape participants showing a more significant deviation from direct paths (F-statistic = 19.60, p = 2.37 × 10−3). Visual engagement data, analyzed through a chi-square test, indicated that vertical elements like walls approached significance in attracting visual attention (Chi-square = 2.88, p = 0.0896), while other elements like trees and benches had less impact. The Wilcoxon signed-rank test results showed significant differences between real-world and VR experiences in perceived openness (W-statistic = 0.0, p = 0.001953), ease of movement (W-statistic = 0.0, p = 0.001953), and comfort (W-statistic = 0.0, p = 0.001953), highlighting VR’s limitations in replicating the full embodied experience of physical spaces.

PERBANDINGAN KINERJA STRUKTUR KOLOM BULAT DAN KOLOM PERSEGI BETON BERTULANG TERHADAP BEBAN GEMPA DENGAN ANALISIS PUSHOVER

Column is a vertical structural element that functions to absorb axial loads and transfer them to the foundation. The structure of this column consists of reinforcement and concrete which is a combination of tensile and compression resistant materials. The column carries a combination of axial loads and ultimate moments simultaneously. The column must have strength where the strength of the column must exceed the working load. The purpose of this study was to obtain differences in the performance of reinforced concrete building structures using circular and square columns due to earthquake loads. The research method used is a quantitative method with the help of SAP2000 software with nonlinear Pushover analysis. There are two models in this study, namely Model M1 is a square column model and model M2 is a circular column model. The results of the analysis show that the behavior of the structure for lateral deformation in the X direction of the square column is stiffer than the round column, while the lateral deformation in the Y direction of the circular column is stiffer than the square column. This is influenced by the inertia of the cross-section and the number of columns in each direction is different. The forces in the square column are 1% greater, the shear force is 62% smaller and the axial force is 24% greater than the circular column. The square column model with IO performance level has the ability to accept lateral loads and deformations on a larger capacity curve compared to circular columns for X and Y direction earthquakes.

Robustness of Dry‐Assembled Precast Wall and Coupled Wall‐Frame High‐Rise Structures With Voided Prestressed Slabs

ABSTRACTPrecast concrete structures are recognized among the structural typologies that may mostly suffer from progressive collapse as a consequence of local unpredicted damage, also due to past accidents occurred in buildings employing old precast technologies neglecting the basic robustness criteria and characterized by poorly detailed and/or executed joints and connections. Although vertical ties may relatively easily be provided in both frame and wall panel structures by employing ductile connection devices, dry‐assembled precast systems avoiding concrete pouring in the whole superstructure typically struggle to provide horizontal ties as strong as required by the current standards concerning progressive collapse, in which they are not fully framed yet. Nevertheless, these systems may exploit alternative sources of robustness to stop collapse progression arising from their structural arrangement, the shape of the slab elements employed, and the slab mechanical connections. This article presents the results of a numerical investigation focused on the structural behavior of a dry‐assembled precast floor system consisting of prestressed box‐section slab elements employed in either wall panel or coupled wall‐frame structural systems following the loss of one or multiple primary load‐bearing vertical elements. Nonlinear static simulations of different loss scenarios occurring in prototypes of 100‐m‐tall high‐rise buildings were carried out based upon spread plasticity modeling of the structural elements and experimentally calibrated nonlinear behavior of mechanical connections.

In situ tests of building structures isolated by innovative three‐dimensional vibration isolation bearings

AbstractAn innovative three‐dimensional vibration isolation bearing (3D‐VIB) was proposed in past studies to mitigate rail‐induced vibration and improve the seismic performance of buildings. The 3D‐VIB was composed of a thick laminated rubber bearing as the vertical vibration isolation element and a friction pendulum system as the horizontal seismic isolation element. In this study, in situ tests were carried out on a subway over‐track structure with 3D‐VIBs. The in situ tests included the subway‐induced vibration excitation test and the horizontal loading test on the same structure. In the subway‐induced vibration excitation test, the vertical isolation performance of the test structure was changed by transforming the isolation layer from a normal vibration‐isolation‐state to a non‐isolation‐state. The comparison between the two states proved that the installation of 3D‐VIBs significantly changed the vertical vibration mode and reduced the subway‐induced vibration of the superstructure. The shear performances of the isolated structure were examined by the horizontal loading test, which subjected the superstructure to a large horizontal movement under external load. The shear performances of the structure with 3D‐VIBs were consistent with that of the 3D‐VIB specimens measured in the laboratory. The in situ tests confirmed the effectiveness and stability of the 3D‐VIBs when applied to practical engineering.

Structural System and Computational Dynamic Model of a Life-Saving Multi-Storey Building with a Kinematic Seismic Isolation System

Introduction. In design of a life-saving multi-storey building, a seismic isolation system in the form of the kinematic supports is used to ensure the seismic resistance and reduce the seismic loads. The structural system, the computational dynamic model and the results of the intermediate in-situ tests of a life-saving multi-storey building with a kinematic seismic isolation system being built in Grozny have been analysed in the article.Materials and Methods. The research included modeling and computation of the structural system of a building with a kinematic seismic isolation system. In-situ tests were carried out to confirm the working capacity of the seismic isolation system connections.Results. A multi-storey life-saving building was designed according to a frame-core wall structure, where the vertical load-bearing elements were core walls, columns and connections between the columns in the form of the stiffening diaphragms. The high-rise part of a building was designed using a kinematic seismic isolation system consisting of the seismic isolating concrete-filled steel tubular supports. The results of the calculations of the main and specific load combinations and internal forces in the load-bearing structures have been presented.Discussion and Conclusion. The research has shown that the use of the developed structural system of seismic isolation with kinematic supports makes it possible to reduce the seismic loads and the total weight of a building and at the same time to increase its mechanical reliability and safety. The conducted intermediate in-situ tests have confirmed the working capacity of the joints connecting the supports with the monolithic reinforced concrete structures of a building, which makes it possible to implement the kinematic seismic isolation supports into the construction industry practices.

Optimizing steel plate shear wall performance: influence of infill plate thickness and connection length to vertical boundary elements

The Steel Plate Shear Wall (SPSW) is widely used as a lateral force resisting system in areas prone to high seismic activity. This is because of its exceptional ductility and ability to dissipate energy. Previous studies have indicated that disconnecting the infill plate from the Vertical Boundary Element (VBE) can decrease the demands on the column. The observed outcomes lead to a decline in both the energy dissipation capability and the lateral load-bearing capacity. The primary goal of this investigation is to mitigate stress on the column while concurrently reducing both the energy dissipation and lateral force capacities. To accomplish this, a partial connection will be established between the infill plate and the Vertical Boundary Element. Thus, the overarching objective of this research is to identify the optimal connection length that minimizes the demands on the column while simultaneously curtailing the reduction in energy dissipation and lateral force capacities. Using Abaqus software, twenty models with different infill plate thicknesses and lengths of connection between the infill plate and Vertical Boundary Element were analysed. To determine the optimal length of connection between the infill plate and Vertical Boundary Element, the energy dissipation capacity, lateral load capacity, and column stresses were evaluated and compared. The maximum dissipation of energy occurs at a connection length of 75% between the infill plate and Vertical Boundary Element and an infill plate thickness of 12 mm. In contrast, the greatest lateral load capacity is achieved at connection lengths of 50% between a 25 mm infill plate thickness and a Vertical Boundary Element weight of 25%. The column stress reaches its minimum value when the infill plate measures 20 and 25 mm, and it reaches its maximum value when the infill plate measures 6 mm and 12 mm. By increasing the thickness of the infill plate and minimizing its connection to the Vertical Boundary Elements, the column stress in Vertical Boundary Elements can be decreased, while simultaneously enhancing lateral load capacity and maintaining an adequate level of energy dissipation.

The Unique Morphofunctional Structure of the Reptilian Heart

The paper analyzes the evolution of the thermoenergetic statuses of vertebrates and the associated evolutionary development of their heart. The analysis shows that in most modern lepidosaurs and turtles, the heart is not completely, conditionally five-chambered: it has two atria and one ventricle, in which two incomplete septas divide it into three functional chambers. In some of them, these two septas were modified in evolution so that they turned into one with vertical and horizontal elements, as a result of which the heart became functionally four-chambered, with improved separation of arterial and venous blood flows. Crocodiles have a fully morphologically four-chambered heart. But the hearts of all reptiles, both recent and extinct, perform two opposite functions in parallel – the separation of arterial and venous blood flows and at the same time their regulated mixing. To do this, there are special morphological and physiological mechanisms in their hearts. Such a strange functional duality in the work of the reptilian heart aims to regulate the metabolism level by controlling the amount of carbon dioxide entering the blood flow: increasing the amount of CO2 in the blood flow reduces the metabolic rate, reducing its amount increase metabolism. Mixed blood in reptiles’ blood flow is not an immature, primitive state, but a physiological necessity. Moreover, this method of regulating of metabolic rate is most adequate to the initial, ancestral thermoenergetic state in reptiles, because basal terrestrial tetrapods and most ancient reptiles were meso- and even tachymetabolic, i.e. almost or completely warm-blooded, endothermic animals. It was just these endothermic animals that needed such type of metabolism regulation. As a result, all recent reptiles have a complex morphophysiological organization of the heart, which was functionally more suitable for their almost warm-blooded ancestors. Recent reptiles use part of their ancestral properties as an adaptation to new environmental conditions, new environmental requirements, and their new morphophysiological state. This unique organization of the heart is characteristic of all modern and extinct reptiles, and, importantly, it is characteristic exclusively for reptiles due to their original endothermic state.

Cypriot Fabrics? White Slip Pottery and Élite Linen Clothes of the Late Bronze Age

Abstract In this article we will point to the similarity between the decoration on Cypriot White Slip (WS) I and II pottery and contemporary 15th–14th-century BCE “Syrian” elite garments shown in 18th Dynasty Egyptian tombs. Depiction of men and women in the tombs of Rekhmire (TT100), Sobekhotep (TT63), Menkheperraseneb (TT86), and Anen (TT120) show white clothes decorated with both vertical and horizontal elements, with dotted and wavy additions. Such elements find direct parallels in the WS I decorative “vocabulary.” We will examine the possibility that the Cypriot WS pottery imitates elite linen clothing produced during the international Late Bronze Age, some even on Cyprus, as indicated by the mention of “linen of Alashiya” (gad uru Alašiya) in Hittite inventory texts.

EVALUATION OF DEFORMATION PARAMETERS OF SILO FOUNDATIONS REINFORCED WITH SOIL-CEMENT ELEMENTS

The mandatory controlled criterion for steel silos is the limitation of foundation settlement and tilting, which is regulated by DBN V.2.6-221:2021. The threshold value of silo settlement is Smax,u = 150 mm. The most economical foundation solution is a large-sized slab on a natural base or a soil cushion. It is possible to stabilise the weak base by reinforcing it with vertical soil-cement elements (SCE). In Ukraine, most foundations have an underground gallery or silo floor. When the silos are first loaded, there is geodetic monitoring of the vertical settlement of the silo base and comparison of its data with the threshold values of settlement and tilting. The objective is to investigate the effect of limited-depth soil reinforcement on the stabilisation of the soil base and the average total foundation settlement. The task of the study is to create a methodology for predicting the impact of reinforcement with soil-cement elements on the parameters of the soil base general stiffness for a silo foundation. The research methods are geodetic monitoring of settlements around the perimeter of silo foundations during initial loading at four different elevators with different geological conditions. Thus, the predicting method of the impact while reinforcing with soil-cement elements on the general stiffness parameters of the soil base for the silo foundation was tested on the bases of silos for four elevators. These elevators represent different engineering and geological conditions. The proof of the methodology’s validity is the coincidence with the results of geodetic subsidence monitoring along the perimeter of silo foundations. According to the research results, it is possible to state that the reinforcement of the foundation base with vertical soil-cement elements allows for the effective stabilisation of soil parameters. We propose an evaluation method of the reinforcement effect with soil-cement elements in the form of the stabilisation coefficient for the soil base, kEi. We further prove the primary role of the soil-cement reinforcing elements operation and their length while stabilising the base. The base stiffness is stabilised at the compressible stratum depth and beyond the foundation boundaries. It is possible to use the method of reinforcement influence evaluation to determine the actual parameters of the stabilised soil base, n, according to geodetic monitoring data. The authors have studied the effect of limited depth reinforcement for stabilising the foundation. The research obtained the empirical dependence of the reinforcement required depth at given depth values for the base compressible layer. The authors proposed using the linearly deformed layer method, considering the operation of soil-cement elements as discrete soil reinforcement. The numerous experiments with the Finite Element Method confirm the high convergence of the calculated results with those obtained analytically. Keywords: foundation settlement, soil-cement element, geodetic monitoring, steel silo, foundation stiffness.

Sensitivity and Optimization Analysis of Torsional Behavior in Multicellular Thin-Walled Tubes

Multicellular thin-walled tubes are widely used due to their lightweight, economical design, and superior shear and torsional performance. Their design is sometimes governed by the available materials and the required dimensions. The current study uses advanced sensitivity analysis with meta-modeling tools to understand how different geometric and mechanical factors affect the torsional performance of multicellular thin-walled tubes. The geometric factors include the length, thickness, and width of the beams, while the mechanical properties involve the shear modulus. Variance-based sensitivity analysis is used to assess how variations in these factors impact the rate of twist, torsional stiffness, and shear stress. The interconnected relations between input parameters are exploited for optimal design and superior performance. The results revealed that for a three-celled tube, thick horizontal interior elements with thin deep vertical elements and thin exterior elements provide an optimal design when the cross-sectional area is constrained. This finding, combined with varying the geometrical and material properties, results in an optimal design using CFRP composites when constrained by minimizing the total weight and superior torsional performance. The analysis can be extended to include other constraint(s), but changing the design constraints might change the optimal design. Doi: 10.28991/CEJ-2024-010-09-09 Full Text: PDF

Exploring the Impact of Vertical Access Elements on Visual Richness and Space Quality within Shopping Mall Atriums

Exploring the Impact of Vertical Access Elements on Visual Richness and Space Quality within Shopping Mall Atriums

Shear resistance design of prefabricated corrugated steel plate shear walls with reinforced boundary elements

This paper investigates the buckling behavior and shear-bearing capacity of prefabricated corrugated steel plate shear walls (PCSPSWs) with reinforced vertical boundary elements (VBEs). The PCSPSWs are solely connected to the frame beams, and therefore, they can be positioned flexibly within the frame. However, there is currently no available shear-bearing capacity design method for such PCSPSWs. Firstly, this paper conducts a numerical investigation into the elastic buckling behaviors of PCSPSWs using finite element analysis (FEA). The prediction formulas for elastic buckling loads are fitted considering the influence of VBEs’ stiffness on the corrugated steel plates (CSPs). Then, the elastic-plastic buckling performance of PCSPSWs is analyzed numerically. The stability factor (φ) is proposed to predict the shear-bearing capacity of PCSPSWs by introducing the normalized slenderness ratio (λn). Subsequently, this paper explores the effects of PCSPSWs’ position within the frame and the influence of linear stiffness ratios between the frame beams and columns on the shear-bearing capacity of PCSPSWs through numerical analysis. Finally, the lower stiffness values of VBEs are discussed to provide some guidance for structural designers.

Vertical elements in architectural landscaping spaces

Vertical elements in architectural landscaping spaces

Adding Green to Architectures: Empirical Research Based on Indoor Vertical Greening of the Emotional Promotion on Adolescents

Good architectural space design can bring positive emotional stimulation and relaxation to users, but few studies have investigated the quantitative indicators in architectural space design and their impact on user emotions. This study takes the right-angle sandwich interface system in architecture as an example to guide the next vertical greening simulation experiment by comparing the spatial quantitative differences in connection value, integration degree, and population agglomeration. Eighty adolescent volunteers were recruited into a control (artificial decorative wall) and experimental (green wall) group based on wall type. We compared their physiological and psychological indicators, including blood pressure and blood oxygen, and psychological indicators, including POMS and SIAI-S scales. Then, we made predictive factor judgements on vertical green elements. The quantification of the interior space of the building showed consistency in parameter changes, with the central area being the area of connectivity, integration, and crowd aggregation values. After the experiment, the experimental group showed a significant decrease in diastolic blood pressure, systolic blood pressure, and heart rate (p = 0.00) and a significant decrease in tension, anger, fatigue, depression, and panic (p = 0.00). The quantitative relationship between vertical greening elements and emotional promotion using stepwise linear exploration shows that the “vine” element is a significant predictive factor for diastolic blood pressure, T-A emotion, and SIAI-S values. The results enrich the indoor optimization and creation expansion paths of interface systems for various spatial experiences and further provide guidance for urban indoor green construction plans and green landscape facility planning via the emotional influence of indoor vertical space greening on young people.

COMPARATIVE STUDY OF FLAT SLAB DESIGN USING VARIOUS INTERNATIONAL CODES

The structural function of beamless floor system is to collect the gravity load and other load such as wind load etc. and to transfer to the vertical structural elements i.e. column through the combined capacity in flexure and shear. In Flat slab, the slab is directly supported on the columns. Moments and shear values are usually the largest over the columns. However, when spans are relatively small and imposed load is low, the thickness of slab can be increased to reduce the stresses at slab-column joint which would result in providing greater effective depth for negative moments occurring near the column. With increasing span and live load intensity, the thickness requirement increases which does not give economical solution. So, to tackle this problem flaring of the column at top is done such that the plan geometry at the column head is similar to that of the column. The column capital is intended primarily to increase the capacity of the slab to resist punching shear. The column capital stiffens the slab, which help in controlling the floor deflection. Thus, the floor span can be increased to some extent. Beyond a certain range of span, further stiffening of the slab is required which is achieved by increasing the slab thickness of the slab panel around the column capital. This portion of the slab is known as drop panel. For flat slabs and flat plates supported directly by columns, shear may be the critical factor in design. In almost all tests of such structures, failures have been due to shear or perhaps shear and torsion. These conditions are particularly serious around the exterior columns. In the present study, attempt has been made to understand different methods of analysis of flat slab and parameters, which governs the design parameters of the flat slab. Attempts have been made to study the provisions of flat slab in well-known international standards such as ACI 318, EC-2 and IS 456:2000. Keywords: Flat slab, drop panel, Column head, IS 456:2000, ACI 318, EC-2

Parametric analysis of a strain state of a soil base strengthened with vertical elements

Purpose is to identify vertical displacements of the “soil basem strengthened with piles or micropiles based upon drilling-mixing technology” system relying upon parametric analysis of strain state of the mentioned system, and arrangement of the strengthening elements. Methods. Mathematical modeling took place for twelve finite-element models using the computing complex SCAD intended to analyze strength of structures by means of finite-element method. Numerical analysis was carried out with variation of elastic-strain modulus of vertical reinforcing elements and change in distance between them (3d and 6d of micropiles). Findings. Results of parametric analysis have been obtained for a model without a micropile (non reinforced soil base); a model with a single micropile; a model with two micropiles where distance between them is 1.5 m, i.e. 3d of micropiles; and a model with two micropiles where distance between them is 3.0 m, i.e. 6d of micropiles. The performed comparative analysis has made it possible to obtain the results proving the hypothesis by the authors as for the specific nature of vertical displacement formation of the “soil base strengthened with piles or micropiles based upon drill-mixing technology” system. Originality. It has been identified for the first time that basing upon the standardized document for the auger or displacement piles, it is impossible to decrease efficiently vertical displacements while approaching micropiles since distance between the micropiles is 3d for elements, developed on the basis of the drilling-mixing, is minimal. Practical implications. The obtained results of a strain state may become the keystone for the development of the genera-lized strain theory of the composite “soil base strengthened with piles or micropiles based upon drilling-mixing technology” system as a medium differing in minor changes of strain characteristics.

Cost-Effective Data Acquisition Systems for Advanced Structural Health Monitoring.

With the growing demand for infrastructure and transportation facilities, the need for advanced structural health monitoring (SHM) systems is critical. This study introduces two innovative, cost-effective, standalone, and open-source data acquisition devices designed to enhance SHM through the latest sensing technologies. The first device, termed CEDAS_acc, integrates the ADXL355 MEMS accelerometer with a RaspberryPi mini-computer, ideal for measuring strong ground motions and assessing structural modal properties during forced vibration tests and structural monitoring of mid-rise buildings. The second device, CEDAS_geo, incorporates the SM24 geophone sensor with a Raspberry Pi, designed for weak ground motion measurements, making it suitable for seismograph networks, seismological research, and early warning systems. Both devices function as acceleration/velocity Data Acquisition Systems (DAS) and standalone data loggers, featuring hardware components such as a single-board mini-computer, sensors, Analog-to-Digital Converters (ADCs), and micro-SD cards housed in protective casings. The CEDAS_acc includes a triaxial MEMS accelerometer with three ADCs, while the CEDAS_geo uses horizontal and vertical geophone elements with an ADC board. To validate these devices, rigorous tests were conducted. Offset Test, conducted by placing the sensor on a leveled flat surface in six orientations, demonstrating the accelerometer's ability to provide accurate measurements using gravity as a reference; Frequency Response Test, performed at the Gebze Technical University Earthquake and Structure Laboratory (GTU-ESL), comparing the devices' responses to the GURALP-5TDE reference sensor, with CEDAS_acc evaluated on a shaking table and CEDAS_geo's performance assessed using ambient vibration records; and Noise Test, executed in a low-noise rural area to determine the intrinsic noise of CEDAS_geo, showing its capability to capture vibrations lower than ambient noise levels. Further field tests were conducted on a 10-story reinforced concrete building in Gaziantep, Turkey, instrumented with 8 CEDAS_acc and 1 CEDAS_geo devices. The building's response to a magnitude 3.2 earthquake and ambient vibrations was analyzed, comparing results to the GURALP-5TDE reference sensors and demonstrating the devices' accuracy in capturing peak accelerations and modal frequencies with minimal deviations. The study also introduced the Record Analyzer (RECANA) web application for managing data analysis on CEDAS devices, supporting various data formats, and providing tools for filtering, calibrating, and exporting data. This comprehensive study presents valuable, practical solutions for SHM, enhancing accessibility, reliability, and efficiency in structural and seismic monitoring applications and offering robust alternatives to traditional, costlier systems.

Stress-strain state of building structures taking into account possible local failure of the element

The issue of choosing a structural design and material for supporting structures is an important technical and economic task at the stage of developing a design solution. It depends on a number of factors: consequence class of the structure, reliability of the design solution, savings in basic building materials. The publication provides a classification of design schemes and types of load-bearing structures used in the corresponding solutions. The disadvantages and advantages of using prefabricated and monolithic structures for the installation and subsequent operation of the structural scheme of buildings and structures are considered. Modern design requirements include ensuring the ability of a damaged structure to adapt to new conditions while continuing to function while ensuring the integrity of human life, property and equipment. New conditions mean the consequences of the occurrence of a certain emergency situation, accompanied by weakening or overloading of the load-bearing structures of a structure or soil foundation: a change in the structural design, a combination of new existing loads and a redistribution of internal forces. The publication reflects the results of assessing the redistribution of the stress-strain state of the elements of the “base - foundations - load-bearing structures” system as a result of the implementation of a hypothetical emergency situation with the exclusion of the load-bearing structure from operation. The case of the collapse of one of the vertical load-bearing elements (local failure of the pylon) of an underground floor, which can be used as a dual-use structure, is considered. Calculations for the stability of the structure against progressive collapse were carried out by numerical modeling in the LIRA SAPR-2019 software using a quasi-static calculation and the method of direct integration of dynamics over time. It has been demonstrated that the method of numerical modeling the joint work of a building with a soil base affects the results of a calculation of the progressive collapse of the building frame. The influence of local collapse of a vertical load-bearing element on the redistribution of stresses and strains in the foundation structures of a building section is assessed. The load on the piles under the pylons around the element removed under the local failure scenario is expected to increase by 15...25%.

Multi‐objective optimization design of concrete outriggers based on Genetic–HookeJeeves algorithm: Reducing lateral deflection, differential axial shortening, and construction cost of the structure

SummaryIn the context of tall concrete structures, it is crucial to not only control the lateral displacement of the building but also address the issue of differential axial shortenings in its vertical elements. Concrete outriggers, commonly resembling relatively stiff beams spanning one to two floors, connect the central core to exterior columns. The strategic placement and appropriate stiffness of these outriggers at different heights of the structure can significantly influence the overall behavior of the entire structure. This study focuses on optimizing the location, depth, and thickness of concrete outriggers, along with the dimensions of beams and columns, as well as the thickness of the core shear wall with the objective of minimizing construction costs and mitigating the occurrence of lateral displacement and differential axial shortenings within the structure. To achieve this, a combined approach of the Genetic–HookeJeeves algorithm has been employed. In this research, we have integrated HookeJeeves, a local search algorithm, with the genetic algorithm to create a hybrid approach that demonstrates high convergence performance. The structural modeling and analysis were conducted using ETABS finite element software, while a Euro‐International Concrete Committee model (CEB model) was utilized to assess the magnitude of differential axial shortenings, enabling us to approximate the long‐term behavior of concrete. The findings of this study highlight the significant impact of the location and stiffness of outriggers on mitigating both lateral displacement and differential axial shortenings within the structure. Optimal placement of an outrigger resulted in a 16% reduction in lateral displacement, and this value could reach up to 25% when the outrigger possessed the ideal stiffness. Additionally, such an arrangement led to a remarkable 36% decrease in the maximum differential axial shortening observed in the structure. These outcomes demonstrate that meeting the design requirements of the intended structure not only improves its performance but also reduces construction costs by 31%.