Wall System Research Articles

Çapraz Lamine Ahşap (CLT) Malzemeli Çok Katlı Konut Binasının 6 Şubat 2023 Kahramanmaraş Depremleri Altındaki Sismik Tepkisinin Değerlendirilmesi

The February 6, 2023 Kahramanmaraş earthquakes exposed the vulnerabilities of existing RC structures, causing thousands of buildings to collapse or sustain severe damage, especially in the hardest-hit provinces. Cross-laminated timber (CLT), one of the industrial wood materials, is used as an alternative to RC in buildings in earthquake zones around the world due to its lightness and many positive features. The aim of the study is to examine the dynamic behavior of multi-storey residential buildings built with the CLT shear wall system, with limited application in Turkey, under earthquake loads and to draw attention to the material selection and sizing to be used in the structural elements of earthquake-resistant buildings. Using TimberTech (2022) software, a five-story building with CLT walls was analyzed under linear dynamic conditions. The study shows while the model provides all the verifications in the solution according to Eurocode for soil type C, it is inadequate under the seismic data of the Kahramanmaraş earthquake.

Machine Learning-Based Indoor Relative Humidity and CO2 Identification Using a Piecewise Autoregressive Exogenous Model: A Cob Prototype Study

The population of developed nations spends a significant amount of time indoors, and the implications of poor indoor air quality (IAQ) on human health are substantial. Many premature deaths attributed to exposure to indoor air pollutants result from diseases exacerbated by poor indoor air. CO2, one of these pollutants, is the most prevalent and often serves as an indicator of IAQ. Indoor CO2 concentrations can be significantly higher than outdoor levels due to human respiration and activity. The primary objective of this research was to numerically investigate the indoor relative humidity and CO2 in cob buildings through the CobBauge prototype, particularly during the first months following the building delivery. Both in situ experimental studies and numerical predictions using an artificial neural network were conducted for this purpose. The study presented the use of a piecewise autoregressive exogenous model (PWARX) for indoor relative humidity (RH) and CO2 content in a building constructed with a double walling system consisting of cob and light earth. The model was validated using experimental data collected over a 27-day period, during which indoor RH and CO2 levels were measured alongside external conditions. The results indicate that the PWARX model accurately predicted RH levels and categorized them into distinct states based on moisture content within materials and external conditions. However, while the model accurately predicted indoor CO2 levels, it faced challenges in finely classifying them due to the complex interplay of factors influencing CO2 levels in indoor environments.

Experimental and numerical evaluation of seismic behavior of coupled walls connected by post-tensioned, unbonded, precast concrete coupling beams

To investigate the seismic performance of coupled shear walls, which are connected by post-tensioned, unbonded, precast concrete coupling beams (PCCB), two 1/7-scale experiments with 8-story coupled shear walls under cyclic lateral loadings were conducted. Coupling of concrete shear walls is achieved by post-tensioning concrete beams to the wall piers using unbonded post-tensioning tendons (UPT) at the floor and roof levels. Experimental results show that little damage occurs in the coupling beams and the wall regions when the specimen undergoes large nonlinear displacements. The residual displacements of the specimen are small because of the restoring effect of the post-tensioning force. The seismic performance of three systems including CW-RC (coupled wall systems that use traditional RC coupling beams), CW-UP (coupled wall systems which use only post-tensioning tendons without steel reinforcement through the beam-wall joints), and CW-HUP (shear walls and PCCB that use combinations of steel reinforcement and post-tensioning tendons) are evaluated by means of nonlinear dynamic analysis. The calculation results indicate that the inter-story drift and peak lateral displacements of CW-HUP and CW-UP are greater than that of CW-RC, whereas the residual deformations are reduced because of the self-centering effect of the post-tensioning tendons.

Performance verification of pipe‐embedded wall system in school building and proposal of its optimal control strategy

AbstractIn this study, a thermally activated building system (TABS) installed on the exterior wall as the pipe‐embedded wall (PEW) system in a school building was investigated. The basic performance of the PEW system utilizing well water cascade is verified by unsteady CFD analysis and field measurements. Moreover, in order to improve the utilization efficiency of the thermal potential from well water, the MPC‐based optimal control method with the PEW system to maximize the heat extraction is proposed and verified by unsteady CFD analysis. The analysis results showed that: (1) The PEW system can reduce the peak load from the exterior wall facing different directions at different times. In addition, the PEW system has the effect of stabilizing the indoor thermal environment. (2) The proposed optimal operation strategy improves the energy efficiency, extracting up to 30% more heat and reducing the total heat transmission, which significantly develops the operation efficiency of the PEW system.

Analysis of the maximum reinforcement loads of four MSE walls compared to the values predicted by the AASHTO 2020 specification

Mechanically stabilized earth (MSE) systems are a well-known and applicable solution for retaining walls, that presents a composite structure consisting of layers of backfill soil with rigid or flexible reinforcement inclusions. The stability of the wall system is derived from the interaction between the backfill and soil reinforcements involving friction and tension. The wall facing has as its main function to prevent erosion of the structural backfill. The design of MSE walls is usually divided in two phases: external and internal stability. Although there are many methods to design MSE walls, the Coherent Gravity Method is the most common used for MSE walls reinforced with inextensible (steel) reinforcements, the Simplified Method for both steel and geosynthetics reinforced wall systems and the new one included in 2020, Stiffness Method, to calculate the maximum reinforcement loads, Tmax, for extensible (geosynthetics) reinforced MSE walls (all these methods are outlined in Section 11 of the AASHTO LRFD Bridge Design Specifications 2020) . The main objective of this paper is to carry out the analysis of the 3 methods available at AASHTO and compare the results from full-scale MSE walls and the predicted Tmax values.

Growing indoor environmental infrastructure: designing for microbial diversity with implications for pollutant metabolism and human health

Abstract Urban inhabitants spend upwards of 90% of their time indoors where building design and mechanical air-handling systems negatively impact air quality, microbiome diversity and health outcomes. Urban bioremediation infrastructure designed to improve indoor environmental quality by drawing air through photosynthesizing plants and metabolically diverse rhizospheres have been investigated since the 1960s; however, in-depth analysis of the potential impacts on indoor environments is required: (1) although recent evidence has illustrated human microbiome alteration and associated health benefits related to exposure to green wall systems, the mechanism(s) of diversification have not yet been established, (2) microbial metabolism and airborne chemical dynamics are extraordinarily complex and hypotheses pertaining to rhizosphere microorganisms metabolizing pollutants require more attention. To explore these areas, we applied a shotgun metagenomic approach to quantify microbial diversity and establish preliminary metabolic profiles within active green wall modules spanning a range of growth media and plant selections. Results indicate that fundamental design decisions, including hydroponic vs. organic growth media, support rhizosphere microbiomes with distinct diversity and metabolic profiles which could impact system performance. The described relationships indicate fundamental green infrastructure design represents an opportunity to “grow” indoor microbial diversity and metabolisms with potential benefits for human pollutant exposure and health outcomes.

Green Wall Systems as a Solution for PM2.5 Mitigation in Indoor Environments: Comparing Passive and Active Systems

Green Wall Systems as a Solution for PM2.5 Mitigation in Indoor Environments: Comparing Passive and Active Systems

Theoretical Building Height Limits of Balloon Mass Timber Shear Wall Systems

Theoretical Building Height Limits of Balloon Mass Timber Shear Wall Systems

Experimental and machine learning research on a multi-functional Trombe wall system

Experimental and machine learning research on a multi-functional Trombe wall system

Leveraging Artificial Intelligence to Reduce Human-Animal Conflict in India

The case focuses on the use of artificial intelligence (AI) and computer vision (CV) technologies to solve a socially complex issue of human-animal conflict in the geographical regions surrounding the Tadoba Andhari Tiger Reserve (TATR) in Maharashtra state in central India. Due to an increasing tiger population, the villages surrounding the TATR often encountered tigers that strayed outside the reserve, sometimes leading to injuries or fatalities either to the humans or the wild animals involved. Valiance, a technology company, collaborated with the Forest department and other local stakeholders to create a computer vision based AI virtual wall system as a pilot project. The technology solution monitored the location 24hrs a day 7 days a week and had the capability of identifying tigers, leopards, and other predators, and sending out automated, real time alerts to help prevent human-animal conflict situations. Based on the outcome of the pilot, the solution could be refined and then a wider rollout could be planned.

Experimental and Machine Learning Research on a Multi-Functional Trombe Wall System

Experimental and Machine Learning Research on a Multi-Functional Trombe Wall System

Evaluation the life cycle carbon emissions of the aerogel glazing under different weather conditions

Carbon emissions are widely recognized as the primary cause of global warming over the past few decades. The Aerogel Glazing System (AGS) stands out as one of the most advanced glazing systems currently available. In order to evaluate the carbon-saving potential of AGS, the life cycle carbon emission model of AGS was established. The carbon emission of production, transportation, construction, operation, maintenance, and waste disposal are considered. The results showed that AGS has higher carbon-saving potential. The life cycle carbon emissions of AGS in commercial, double glazing system (DGS), triple glazing system (TGS) are −144.8 kg CO2/m2, 593.6 kg CO2/m2, 250.8 kg CO2/m2 in Beijing horizontal direction. Under high temperature supercritical drying (in Commercial), low temperature supercritical drying, and freeze-drying, the life carbon emissions of AGS are lower compared to both DGS and TGS. Then the life cycle carbon emissions of AGS in different climates were analyzed. The results show that the life cycle carbon emissions of AGS under different climatic conditions are as follows (in ascending order): subtropical climate < polar climate < temperate climate < arid climate < tropical climate, with a maximum of 4929.9 kg CO2/m2 and a minimum of −634.5 kg CO2/m2. The use of AGS in tropical climate produced 5.9 times increase in life carbon emissions compared to its use in subtropical climate. In the heating-dominated climate, AGS has the greatest potential for carbon savings when orientated southwards. In cooling dominated climates, the carbon emissions are higher in the southward direction, with a weaker potential for carbon savings. Interestingly, in polar and tropical climates, increasing the aerogel thickness layer effectively reduces the life cycle carbon emissions of AGS. This study provides valuable insights for selecting sustainable curtain wall systems and window configurations, offering a pathway to minimize environmental impacts.

Reinforced Soil Wall Construction with High Stiffness Geocomposite Reinforcement and Betoflor Segmental Block, Pengerang, Johor Darul Ta’zim

Pengerang is a municipality in Kota Tinggi district in Johor at the southern tip of the Peninsular Malaysia. It is home for the mega oil and gas hub Pengerang Integrated Petroleum Complex (PIPC) in Southern Johor state, which is one of the region’s largest hubs for oil and gas, petrochemical industries, oil storage and trading activities. The area is experiencing significant development, both residential and commercial in nature. In this development plan, the retaining wall system plays a crucial role in providing a larger development area, enhancing the aesthetic view, and achieving a higher elevation platform. The focus of this paper is on an internally stabilized reinforced soil wall system which involves reinforcing the soil with high stiffness geocomposite reinforcement and utilizing modular segmental blocks as facing elements. This combination creates a 1 vertical: 0.14 horizontal gradient (82°) wall that is implemented for a mixed development at Pengerang. The single-tier reinforced soil wall reaches a height of 13 m. In addition, the maximum 14 m high wall was designed as a two-tier wall and the maximum 19 m high wall was designed as a three-tier wall. The design of the reinforced soil wall includes the evaluation of various potential internal and external failure modes. This paper also discusses the construction sequences employed for the reinforced soil wall. Ultimately, the combination of the high stiffness geocomposite reinforcement with modular segmental blocks has proven successful, resulting in a constructed wall that satisfied the client requirements

Unraveling the Mongolian Arc: a Field Survey and Spatial Investigation of a Previously Unexplored Wall System in Eastern Mongolia

ABSTRACT This paper explores, for the first time, a 405 km long wall system located in eastern Mongolia: the “Mongolian Arc” consists of an earthen wall, a trench, and 34 structures. It is part of a much larger system of walls built between the 11th and 13th centuries a.d. The Mongolian Arc, despite its magnitude, has been largely overlooked in existing academic discourse. Our team collected remote sensing data of different types and conducted an archaeological field survey of the entire Mongolian Arc. The different datasets obtained in the lab and the field were analyzed using a geographic information system (GIS). These results were integrated with excerpts from relevant primary sources to provide a preliminary interpretation of the design and potential functions of the Mongolian Arc. Key areas of exploration include the idiosyncratic gaps along the wall, the spatial organization of the wall and structures, and their interrelationship with the adjacent landscape.

Mechanical Performance and Selection Study of High-Rise and Super High-Rise Building Structural Systems

This study focuses on the structural systems of high-rise and super high-rise buildings, with particular emphasis on their mechanical performance and selection. The structural design of high-rise buildings is of paramount importance, requiring safety and stability to be ensured. This paper discusses various structural types, including steel structures, reinforced concrete structures, and their combination structures. Additionally, it analyzes the characteristics and applicability of various vertical load-bearing structures such as frames, shear walls, frame-shear wall systems, cores, and mega-structures, considering their performance under different heights and geographic conditions. Finally, it presents the maximum applicable heights for each structural system, emphasizing the significance of selection in meeting urban demands.

Prefab Facades – From Prototype to Product?

Building envelopes are not only the prime element of the exterior aesthetic quality of buildings; they have also become a major driver both for building construction cost and operational performance. The importance of prefabrication is growing in the building industry as it allows faster, high-quality, and cost-effective construction while reducing risks associated with onsite labour. Although prefabrication for structural components is a relatively recent development, it has been widely used in the manufacturing of building envelopes for many years, particularly in the case of unitized curtain wall systems. However, whether using prefabricated components or not, façade design development remains a challenge due to the need for façade engineers to rapidly develop technically viable and financially feasible solutions that achieve the desired architectural design intent. Particularly at the early stages of the design process, the turnaround for multiple iterations is often fast-paced, and abortive work is, therefore, not uncommon. This paper outlines an approach to addressing this challenge, attempting to bridge the gap between façade design, fabrication, and installation. A new design approach and tools are presented that allow designers to iteratively validate concepts based on a pre-engineered system that is optimized for performance and take fabrication, transport, installation costs, maintenance, and circularity into account. As a result, the tool/design workflow will ensure consistent quality, meeting budgets and timelines while enhancing material efficiency and fostering energy-conscious and circular envelope design approaches.

High-Rise Residential Timber Buildings: Emerging Architectural and Structural Design Trends

High-rise residential timber buildings (≥8 stories) are an emerging and promising domain, primarily owing to their capacity to deliver notable environmental and economic benefits over the entire span of their existence. However, it is worth noting that the current body of scholarly work falls short in providing a thorough examination of the key aspects related to architectural and structural design for these environmentally sustainable towers. In an effort to bridge this knowledge gap and deepen our comprehension of the evolving worldwide trends, this research delved into data collected from 55 case studies conducted across the globe. The primary findings unveiled the following: (1) Europe, particularly Nordic countries, stood out as the region boasting the highest number of high-rise residential timber buildings, with North America and the United Kingdom following suit; (2) central cores were the prevailing choice for the core configuration, with the peripheral type following as the second most common option; (3) prismatic forms were the most commonly favored design choices; (4) widespread prevalence of employing pure timber was observed, followed by timber and concrete composite combinations; and (5) structural systems were predominantly characterized by the utilization of shear walled frame and shear wall systems. This research aims to reveal the current attributes of high-rise residential timber buildings, with the expectation that it will offer architects valuable knowledge to assist and steer them in planning and implementing forthcoming sustainable projects within this domain.

Life cycle assessment and life cycle cost analysis of different walling materials with an environmental approach (comparison between earth-based vs. conventional construction techniques in Iran)

PurposeClimate change, environmental concerns, and economic problems pose challenges to the construction sector in Iran, which must provide affordable solutions while addressing environmental issues. Hence, natural earthen building materials are critically needed to reduce energy-intensive and costly construction practices dramatically. The purpose of this paper is to provide a framework for comparing life cycle assessments (LCA) and life cycle costs (LCC), for load-bearing walls of an single-family affordable housing unit in a desert part of Iran, Ardakan City.MethodsTo do so, both LCA and LCC for the unit were performed, considering a cradle-to-site perspective. For this purpose, 22 load bearing wall systems are assessed, including 18 stabilized and unstabilized earthen construction techniques, such as adobe, rammed earth (RE), and compressed earth block (CEB), in addition to four conventional wall assemblies of fired brick (FB), autoclaved aerated concrete block (AAC), ceramic block (CB), and concrete masonry unit (CMU). As well as assessing the environmental impact and life cycle costs associated with the life cycle of each wall, the optimal assembly of the wall is also examined.ResultsResults show that unstabilized earthen walling alternatives have significantly lower environmental impacts than conventional materials.ConclusionsSensitivity analysis indicates that by utilizing local materials to the maximum extent possible, impacts can be further minimized. Considering the results, transportation may even account for a greater proportion of EI than wall components.

DYNAMICS OF THE FORMATION OF THE PHENOLIC REDOX SYSTEM OF CONIFEROUS PLANTS ON THE EXAMPLE OF THE COMMON PINE PINUS SYLVESTRIS

The change in the quantitative composition of secondary metabolites in the forming plant tissue is associated with climatic conditions of plant growth, including seasonality and the growing season. Acclimatization of evergreen coniferous trees in boreal regions includes regulatory processes that protect the photosynthetic apparatus of needles in specific conditions. Using the example of coniferous tree – scots pine (Pinus sylvestris), new experimental data on changes in the content of secondary metabolites of phenolic nature – participants in the processes of plant tissue biosynthesis – is presented in this paper. The dynamics of the intensity of phenolic metabolism and the quantitative change of the pigment apparatus of pine needles during the growing season were investigated using a complex of physic-chemical methods (UV spectrophotometry, HPLC, redox-metry) and the composition of the phenolic fraction of the phenol-quinone redox system of the cell wall was studied. It is shown that changes in the quantitative and qualitative composition of the phenolic compounds fraction that determine the redox state of the plant matrix occurs in plant tissue throughout the growing season. It is noted that dynamic self-regulation processes involving a complex consisting of phenolic compounds, pigments and enzymatic systems are a common pattern at all stages of plant development, ensuring that they perform protective functions of the photosynthetic apparatus of the needles of evergreen coniferous trees in boreal regions.

Optimizing hybrid ventilation and daylight-linked dimming control for carbon reduction and thermal comfort in a subtropical high-rise office building

The dominant contributors to electricity consumption in existing buildings are air-conditioning and lighting systems. This study aims to optimize hybrid ventilation and daylight-linked dimming control in a subtropical high-rise office building. The objective is to reduce carbon emissions while ensuring thermal and visual comfort. These two strategies can be retrofitted in a typical curtain wall system with vertical windows without encountering any technical limitations. EnergyPlus is used to analyze the impact of these strategies on enhancing thermal comfort and illuminance while achieving electricity savings in the high-rise office building. Based on the typical meteorological year of Hong Kong, using natural ventilation in perimeter zones can reduce the energy use intensity (EUI) by 2.6 to 3.41 % for 30.09 to 34.97 % of total operating hours, depending on window-to-wall ratios (WWRs). Furthermore, daylight-linked dimming control in perimeter zones can reduce EUI by 18.91 % to 21.9 % in the HVAC portion and 8.09 % to 12.25 % in the lighting portion during 91.39 % to 98.28 % of total operating hours. Using daylighting with a high WWR helps reduce 6.31 to 9.21 % in total greenhouse gas emissions. The study also develops a logistic regression model using three climatic variables to predict the natural ventilation status. Overall, the use of daylighting greatly improves the percentage of acceptable predicted mean vote (PMV), with the greatest improvements observed in perimeter zones facing east and west on the middle floors. However, the combined application of both strategies results in a tempered improvement. The novelty of this study lies in providing guidance on suitable WWRs for implementing both strategies to achieve carbon reduction. Moreover, the significance lies in providing a quantitative assessment of how enhanced ventilation and lighting controls contribute to lower carbon emissions while improving thermal comfort.