Sustainable Structural Design Research Articles

Unveiling the seismic sensitivity of the Himalayan tunnels: a comprehensive assessment through analytical and numerical exploration of P-wave dynamics

This study investigated the seismic sensitivity of tunnels in the Jammu Region (JR) of the northwestern Himalayas, a region characterized by significant seismic activity and complex geological conditions. The research combined both analytical and numerical approaches to assess the influence of site conditions, tunnel lining, and reinforcement properties on tunnel resilience. A key objective is to develop a more reliable seismic assessment method by adopting a P-wave-based approach, which is particularly suitable for mountainous tunnels prone to landslides. The study identified three seismic hazard zones, with peak ground accelerations (PGA) ranging from less than 0.3 g to greater than 0.5 g, providing vulnerability aspects. The major outcomes of this study include guidelines for the design and retrofitting of sustainable and resilient underground structures in the Himalayas, with broader implications for global projects in seismically active and geologically complex regions. The methodologies and insights can be applied to infrastructure projects worldwide, enhancing the safety of communities living in vulnerable areas. This work aligns with the United Nations Sustainable Development Goals (SDGs), particularly in promoting resilient infrastructure and sustainable development, contributing to both structural resilience and the geological safety of the Himalayan region.

Integration of GIS and HEC-HMS for sustainable drainage structure modeling

An effective approach to addressing the challenges of overload in urban drainage systems is the integration of Geographic Information Systems (GIS) with hydrological modeling software. In this context, the primary objective of this study was to integrate QGIS with HEC-HMS and apply them to the design of sustainable drainage structures. QGIS was employed to obtain the physiographic characteristics and land use information for the region of interest. Conversely, HEC-HMS was used to perform the water balance for the selected area, aiming to determine the drainage system's flow capacity and the buffering effect provided by a detention basin. The integration of QGIS and HEC-HMS was applied in a specific case study in the municipality of Viçosa, in the state of Minas Gerais. The results of this study highlighted the existing drainage system's inability to handle high flow rates and indicated that implementing a detention basin could help mitigate this issue. The investigated methodology proved to be extremely valuable, allowing professionals involved in the design of urban drainage systems to use it, thereby improving the response capacity and resilience of cities in the face of extreme precipitation events.

Experimental investigation and machine learning models for predicting flexural and tensile strengths of recycled concrete: Bridging the gap between sustainable materials and structural design

The sustainability of structural components requires recycled aggregate concrete (RC) to achieve adequate flexural and split tensile strengths for practical use. These strengths depend on mix design and the properties of recycled coarse aggregates (R-CA). The variability in R-CA sources and the inherent heterogeneity of RC complicate strength predictions. No existing model accounts for this variability, leaving a gap between sustainable materials and structural design. This study develops machine learning-based models to predict the flexural and split tensile strengths of RC, regardless of R-CA source and properties. Key factors such as water absorption, effective water-to-cement ratio, coarse aggregate-to-cement ratio, and R-CA replacement ratio are used for predictions. The impact of different R-CA types on RC and natural aggregate concrete (NC) is also experimentally analyzed. A dataset of 353 test results from this study and 33 prior studies is used, and various machine learning algorithms (MLA) are evaluated. Results show a 41 % and 23 % reduction in flexural and split tensile strengths of RC compared to NC, but acid and mechanically treated R-CA can recover up to 94 % and 93 % of NC's strengths, respectively. Among all MLA models, the gradient boost model depicted the highest accuracy in predictions for the flexural and tensile strengths of both RC and NC. This research introduces new equations and a C/C++ tool for predicting RC and NC strengths, contributing to sustainable concrete design and bridging the gap between research and practical application.

Primary Energy and Carbon Impacts of Structural Frames with Equivalent Design Criteria: Influence of Different Materials and Levels of Prefabrication

This study aims to analyze the life-cycle primary energy and climate impacts of structural frames, paying particular attention to the design and prefabrication of different structural materials. The study considers an existing single-story office building with a composite concrete–steel structure and compares it with two functionally equivalent structures, i.e., a conventional reinforced concrete structure and a conventional steel structure. The existing building is located in San Felice sul Panaro, Italy. This study integrates dynamic structural analysis and life-cycle assessment (LCA). The study finds that the use of different materials can reduce the life-cycle primary energy use and CO2-eq emissions by up to 12%. Furthermore, the benefits derived from the recovery and recycling of materials can reduce the primary energy use and CO2-eq emissions by up to 47% and 36%, respectively. The prefabrication of structural elements can also reduce the primary energy use and CO2-eq emissions in the construction stage. A sensitivity analysis considers changes in the electricity supply system and shows that the primary energy and CO2-eq emissions due to prefabrication decrease when assuming marginal electricity based on renewable energies. This analysis supports the development of sustainable structural design to meet the standards concerning the whole-life-cycle carbon emissions of buildings.

Experimental Investigation of Quasi-Static and Dynamic Impact Resistance in Thin Wood Veneer Laminates

The incorporation of sustainability into the design of transport vehicles has become increasingly important in recent years. A low carbon footprint makes wood-based structures attractive to replace other lightweight materials such as aluminum or fiber-reinforced plastics. This paper investigates and compares the static and dynamic impact behavior of thin Beech wood veneer laminates in standardized mechanical tests. The results obtained from Quasi-Static Indentation (QSI) and dynamic Low-Velocity Impact (LVI) tests reveal similarities and differences with regard to load vs. displacement behavior, damage mechanisms, permanent deformation, and energy absorption. While yield strength and damage modes are comparable in both test cases, it is found that the bending stiffness is strain-rate sensitive. Plastic deformation in compression is identified as the governing mechanism for energy absorption. These results can guide the design of sustainable wood-based structures for future transport applications where a thorough understanding of impact and crashworthiness is important.

The engineering legacy of the FIFA World Cup Qatar 2022TM: Al Bayt Stadium

In contemporary architecture, textile membranes offer a wide range of possible structural applications, especially for facades and roofs with large spans and where the reduction of self-weight plays an important role for an efficient and sustainable structural design. On 30 November 2021, the Al Bayt Stadium was inaugurated in Qatar; with its 190 000 m2 of textile membrane it is one of the biggest architectural membrane projects in the world. An innovative new membrane material with a natural textile appearance was developed from scratch to meet the specific requirements of the project. This makes the construction of Al Bayt Stadium, shaped like the local Bedouin tents, a milestone in modern membrane architecture; this is attributable not only due to the pure size of the membrane, but also to the significant advances made in textile membrane material design and development as part of the project. Other design aspects include the large, retractable roof above the pitch, which transforms the open-air stadium into a fully enclosed and temperature-controlled multi-purpose arena within minutes. This paper presents details of the design and construction aspects of the stadium, as well as the material development conducted for the inner membrane.

Optimizing Concrete Grade for a Sustainable Structural Design in Saudi Arabia

Buildings and facilities undergo several stages: the product stage, the construction stage, the use stage, the end-of-life stage, and the recycling stage. The life cycle of any facility or building contributes to embodied carbon (EC) emissions. The product stage, also known as the cradle-to-gate stage (A1–A3), registers the highest emissions, estimated to account for 70% of the total environmental impact. The continuing population growth in Saudi Arabia necessitates urgent action to identify and implement solutions for reducing greenhouse gas emissions and mitigating environmental risks. This study investigates the optimal method to analyze the grade of concrete for specific structural elements (columns) in a particular work area, adhering to accurate and methodological standards outlined in the Saudi Building Code (SBC). The bill of quantities (BOQ) determined the amount of building materials for the structure considered in this study. Reliable embedded carbon coefficients (ECCs) for structural materials such as concrete and steel were determined following life cycle assessment principles. They were analyzed using the Inventory of Carbon and Energy (ICE; Version 2.0) and Global Warming Potential (GWP). The obtained values varied based on the components of each mixture. This study determined the cost of each concrete mixture and steel, selecting the optimal mixture based on both EC and material cost. Since the quantity of cement significantly affects EC emissions in a concrete mixture, it is essential to select appropriate plasticizers and concrete types. This study evaluated the C30, C40, C50, C60, and C70 mixtures. Among these, the C70 mixture demonstrated the best environmental impact and was the least expensive compared to the basic C40 mixture for the estimated quantities of concrete and steel. The estimated reductions in cost and environmental impact were 33% and 27%, respectively. This groundbreaking study paves the way for low-carbon structural design in large hotels across Saudi Arabia, offering valuable insights for future projects and contributing significantly to energy conservation.

Performance of recycled aggregate concrete composite metal decks under elevated temperatures: a comprehensive review

ABSTRACT This comprehensive review explores the performance of composite metal decks and structural elements incorporating recycled aggregate concrete (RAC) at elevated temperatures. Despite the acknowledged environmental benefits of using recycled aggregates in concrete production, there is a notable gap in the literature regarding their behaviour under fire conditions. The investigation delves into studies encompassing fire resistance, physio-thermal properties, mechanical attributes, and structural performance of composite metal decks constructed with RAC. The analysis reveals that the inclusion of recycled aggregates has both positive and negative impacts on these elements when exposed to high temperatures. The fire resistance of metal decking composite slabs is significantly influenced by material properties, composition, and RAC mix design. Experimental findings indicate that RAC slabs showed larger midspan deflection under load and fire exposure compared to their counterpart NC slabs. After 120 min. of duration, the mid-span deflection of RAC-0 was recorded to be 19 % higher than the corresponding deflection of NC-0 slab. While temperature-time curves show comparable performance between RAC and natural concrete (NC) slabs, RAC slabs exhibit a notably lower ratio of soffit temperature to the upper surface temperature, resulting in increased spalling. In conclusion, this study advocates for the broader utilization of RAC in constructing structural elements, particularly composite slabs facing extreme temperatures. However, it emphasizes the need for additional research to optimize fire resistance and gain a comprehensive understanding of their behaviour. The findings provide essential guidance for structural engineers and researchers involved in the design of sustainable and fire-resistant structures.

Towards BIM-Based Sustainable Structural Design Optimization: A Systematic Review and Industry Perspective

Structural design optimization (SDO) plays a pivotal role in enhancing various aspects of construction projects, including design quality, cost efficiency, safety, and structural reliability. Recent endeavors in academia and industry have sought to harness the potential of building information modeling (BIM) and optimization algorithms to optimize SDO and improve design outcomes. This review paper aims to synthesize these efforts, shedding light on how SDO contributes to project coordination. Furthermore, the integration of sustainability considerations and the application of innovative technologies and optimization algorithms in SDO necessitate more interactive early stage collaboration among project stakeholders. This study offers a comprehensive exploration of contemporary research in integrated SDO employing BIM and optimization algorithms. It commences with an exploratory investigation, employing both qualitative and quantitative analysis techniques following the PRISMA systematic review methodology. Subsequently, an open-ended opinion survey was conducted among construction industry professionals in Europe. This survey yields valuable insights into the coordination challenges and potential solutions arising from technological shifts and interoperability concerns associated with the widespread implementation of SDO. These preliminary steps of systematic review and industry survey furnish a robust foundation of knowledge, enabling the proposal of an intelligent framework for automating early stage sustainable structural design optimization (ESSDO) within the construction sector. The ESSDO framework addresses the challenges of fragmented collaboration between architects and structural engineers. This proposed framework seamlessly integrates with the BIM platform, i.e., Autodesk Revit for architects. It extracts crucial architectural data and transfers it to the structural design and analysis platform, i.e., Autodesk Robot Structural Analysis (RSA), for structural engineers via the visual programming tool Dynamo. Once the optimization occurs, optimal outcomes are visualized within BIM environments. This visualization elevates interactive collaborations between architects and engineers, facilitating automation throughout the workflow and smoother information exchange.

Life-cycle thinking-based decision support framework for multispan simply supported bridges under typhoon-induced wave, current and surge conditions

Coastal bridges usually suffer from wave, current, and storm surge hazards simultaneously under typhoons. Comprehensive mitigation measures can reduce the structural failure probability under these hazards but usually lead to a conservative structural design and a significant increase in the project budget. With the recent development of sustainable structural design, the multicriteria decision-making method can assist engineers in incorporating the life-cycle investment and probability of hazards in the design selection. In this paper, a life-cycle thinking-based decision support framework that considers multicriteria trade-offs and sustainable design was proposed for the design of coastal bridges under typhoon-induced wave, current and surge conditions. The simulation of the typhoon-induced wave, current and surge conditions was developed using SWAN + ADCIRC model, joint probability and environmental contours. The multispan simply supported (MSSS) bridge was then used to illustrate the framework. The main findings include that the void slab girder is better than the other girder types in the equal-weighted, risk-averse and pro-economic scenarios for the example bridge, but the change in girder types has a small impact on the economic cost index score. The increase in the girder height can increase the failure probability when deck shifting dominates the superstructure's failure.

Bending and environmental characteristics of an eco-friendly sandwich panel with cork stopper cores

The design and application of sustainable structures are promising approaches to achieve energy conservation and emission reduction in construction and buildings. Cork stoppers have high recycling value and can be particularly used as the core of eco-friendly sandwich structures. The object of this paper is to assess the eco-mechanical performance of a more sustainable sandwich structure made of eco-friendly cores (natural or agglomerated cork stopper), aluminum alloy skins and resin adhesive. A set of sandwich panels with different packing arrangements are fabricated. Experimental tests are conducted to address the effects of packing topology and cork stoppers’ materials on bending characteristics and failure modes. The life cycle assessment method is adopted to quantify the environmental impacts, and the eco-mechanical performances are further evaluated. The results show that this sandwich structure concept with cork stopper cores has good structural and resource-environment efficiency and could be a promising alternative in construction and buildings.

Large-Scale Self-Assembly of anisotropic graphene oxide films via blade Coating: Sustainable design and Stimuli-Responsive performance for biomimicry

Sustainable structural design, utilizing material to imitate natural biological systems, presents both promise and challenges. By avoiding interfacial problems encountered in composite counterparts, such designs offer self-adaptive materials for smart housing and green architecture, etc. In this study, we demonstrate the feasibility of large-scale self-assembly of graphene oxide (GO) flakes into anisotropic films through a simple blade coating technique. Through the application of blade coating to a highly concentrated nematic GO suspension, we successfully fabricate GO films with morphological gradient and patterning. Additionally, we propose a statistical analysis method utilizing scanning electron microscopy (SEM) images for the characterization of materials with macroscopic surface morphology. Furthermore, we explore the application of these GO films as low-dimensional soft actuators, revealing their outstanding stimuli-responsive performance and self-adaptation to environment. Such robust and flexible films can be used as integral building elements in the bioinspired design of sustainable smart housing facilitating remote robotization and sensing capabilities.

Comparison of Physical and Mechanical Properties of Stone Aggregates and Their Use in the Structure of a Flexible Pavement, from Mines in Ecuador

One of the reasons that cause premature deterioration of the wearing course is the quality of the materials that make up the flexible pavement structure of the road network in Ecuador. Therefore, there is a need to thoroughly study the stone materials, such as coarse aggregate and fine aggregate, which form the structure of the flexible pavement. The quality of these materials will determine the service life of the wearing course as well as the high or low cost of road construction. The main objective of this research was to determine the highest quality material based on its technical and economic characteristics. For this purpose, three main mines that supply stone materials in the country were selected: “Kumochi”, “Los Muelles”, and “Cantera El Salvador”. Several samples of fine aggregate and coarse aggregate were taken from these mines to conduct laboratory tests, including natural moisture content, Atterberg limits, gradation, modified Proctor, and relative density. The California Bearing Ratio (CBR) test was also performed to determine the load-bearing capacity of the samples. These data will be used in future investigations for the design of sustainable pavement structures. Additionally, physical and mechanical properties were determined through tests including aggregate soundness, resistance to abrasion, and the Los Angeles abrasion test to determine the percentage of fractured faces of the coarse aggregate. In conclusion, it was found that the material from the “El Salvador” mine has the best technical and economic characteristics for the formation of flexible pavement structures. However, the material from the “Kumochi” and “Los Muelles” mines met the standards of the international AASHTO norm. The final recommendation after conducting the research is that the aforementioned materials can be used not only for the formation of the pavement structure but also for the wearing course.

Field measurement of the erosion threshold of silty seabed in the intertidal flat of the Yellow River Delta with a newly-developed annular flume

Accurately measuring the critical shear stress is crucial for numerous applications, such as sediment transport modeling, erosion prediction, and the design of sustainable coastal engineering structures. However, developing reliable and precise in-situ measurement devices faces significant challenges due to the harsh and dynamic nature of aquatic environments. Factors like turbulence and waves introduce complexities that must be considered when designing and calibrating these devices. The newly developed Openable Underwater Carousel In-situ Flume (OUC-IF) was used to determine the critical shear stress (τc) and quantify erosion rates. Acoustic Doppler Velocimeter (ADV) was employed to measure 3D near-bottom velocities, which were then used to estimate and pre-calibrate bed shear stress (τ) applied on the seabed in the annular flume. Three computation methods of shear stress were evaluated: turbulent kinetic energy (TKE), direct covariance (COV), and log profile (LP). In-situ erosion experiments were conducted for the first time at two sites in the tidal flat of the Yellow River Delta (site 1 with a water depth of 1.32 m and site 2 with a water depth of 0.75 m). The critical shear stress was found to be 0.10 Pa at site 1 and 0.19 Pa at site 2, and the erosion rates of the sediments were successfully measured. The effect of wave-seabed interactions on erosion resistance was explored by theoretically estimating the wave-induced pore pressure of the seabed based on the observed data. The max liquefaction degree of the seabed at site 1 and site 2 was 0.035 and 0.057, respectively, and the average erosion coefficient Me was 2.63E-05 kg m-2s-1 at site 1 and 3.48E-05 kg m-2s-1 at site 2.

Plastic design of sustainable steel earthquake resistant structures

Earthquakes induce ultimate load conditions in most earthquake resistant structures and often lead to complete failure and disposal. Seismic sustainability is a limit state condition with a view to revival, reuse, and environmental protection. In the present context, sustainable seismic design implies planning for controlled energy dissipation, sequential failures, collapse prevention, construction economy and post-earthquake realignment and repairs. However, regardless of savings and environmental improvements unless an earthquake resistant structure is designed for the purpose, it would be disposable with greater monetary loss and harm to the environment. It has been found that steel mixed multiple seismic systems are well-suited for sustainable seismic design. Mixed multiple structures are combinations of two or more low/controlled damage ductile structures, an articulated gravity frame, a collapse preventive, hybrid, rigid rocking core, and a phantom P-delta system acting together to form a repairable archetype. Each earthquake resistant system is equipped with replaceable energy dissipating and fail-safe devices. Such arrangements call for applications of Plastic Design and Performance Control principles, rather than conventional methods of approach. This in turn calls for development of modern design rules, technologies and details that govern the behavior of such systems equipped with replaceable energy dissipating devices. In the interim several observations that reduce the task of otherwise cumbersome analysis to simple rules of response have been introduced.

Embodied Carbon Minimization for Single-Story Steel Gable Frames

As the construction industry, especially steel construction, contributes to a large portion of global greenhouse gas emissions, sustainable structural design has become a necessity to achieve the world vision of reaching net zero emissions by 2050. As steel portal frames are the most used structural system for single-story buildings, the main objective of this study is to determine the optimal steel portal frame configuration using prismatic and/or non-prismatic members to achieve the least embodied carbon. Five different portal frame configurations are considered under the effect of five distinct loading conditions. The results led to developing design charts consisting of contour plots showing the embodied carbon per unit of volume enclosed by the steel frame for different frame configurations, loading conditions, span lengths, and column heights. In addition, by increasing the number of member divisions, design variables, and non-prismatic segments, the average embodied carbon of the steel portal frames can be significantly reduced by about 14.34% up to 26.47% relative to the configuration with only prismatic members.

CARBON FOOTPRINT OPTIMIZED DESIGN OF SUSTAINABLE REINFORCED CONCRETE COLUMNS USING DEEP LEARNING

The objective of this paper is to present a neural network (NN) model for the sustainable structural design optimization of rectangular reinforced concrete columns under biaxial bending and axial loading to minimize the embodied carbon from concrete and steel. Using the loading combination, height, and concrete class, the model predicts the section geometry and reinforcement ratio. To train the NN, a dataset of 195 million designs was generated with the OpenSees library following Eurocode. The dataset spans six concrete classes and five different column heights. Using the estimates of the embodied carbon for concrete and steel, the designs were evaluated and filtered before training. To illustrate the performance of our model, 30 columns for different loads, heights, and concrete classes were manually designed and compared with the NN output. The results showed a 24% average reduction of embodied carbon for the NN predicted designs. In addition, the manual process took approximately six minutes per design, while it took the NN 1.2 seconds for the same task.

CARBON FOOTPRINT OPTIMIZED DESIGN OF SUSTAINABLE REINFORCED CONCRETE COLUMNS USING DEEP LEARNING

The objective of this paper is to present a neural network (NN) model for the sustainable structural design optimization of rectangular reinforced concrete columns under biaxial bending and axial loading to minimize the embodied carbon from concrete and steel. Using the loading combination, height, and concrete class, the model predicts the section geometry and reinforcement ratio. To train the NN, a dataset of 195 million designs was generated with the OpenSees library following Eurocode. The dataset spans six concrete classes and five different column heights. Using the estimates of the embodied carbon for concrete and steel, the designs were evaluated and filtered before training. To illustrate the performance of our model, 30 columns for different loads, heights, and concrete classes were manually designed and compared with the NN output. The results showed a 24% average reduction of embodied carbon for the NN predicted designs. In addition, the manual process took approximately six minutes per design, while it took the NN 1.2 seconds for the same task.

Systematic Development of Sustainability-Oriented Cyber-Physical Production Systems

Manufacturing companies increasingly have to address the risks and contributions related to their environmental impacts. Therefore, more data are needed in order to provide full transparency with regard to production, and to highlight the potential relationships between the process data and the environmental impacts. In order to achieve this data transparency, targeted digitalization is needed that is tailored to the goal of reaching minimized environmental impacts. Cyber-physical production systems (CPPSs) are central for the digitalization of manufacturing. However, they may also come with an initial environmental backpack. Due to unawareness of relevant interdependencies when setting up CPPS, data may be collected which is not helpful or necessary for the development of sustainability-oriented CPPS. Therefore, a critical assessment is required which data is necessary to support sustainable manufacturing and to avoid unreflective data collection. This requires the identification of the relevant factors and their interdependencies within the context of sustainability in production. By identifying the influencing factors, the measurement strategy can be linked to the appropriate sensor technologies that explicitly contribute to the target fulfillment. The design of more sustainable data structures using a cross-impact analysis is illustrated in this paper as a generic methodological approach, which will be applied to a 3D-printing use case.

Fresh and hardened properties of cemented paste backfill: Links to mixing time

Current technical knowledge is insufficient regarding the influence of mixing time on fresh and hardened properties of cemented paste backfill (CPB). This work focused on experimental studies to gain a deeper understanding of the influence of mixing time on the rheological properties (yield stress, viscosity), self-desiccation, permeability and mechanical properties or behavior (strength, deformation behavior) of CPB. A series of CPB specimens were prepared with various mixing times (1, 2, 4, 7, 10, and 15 min) and cured at different times (1, 2, 4, 7, 10 and 15 min) for rheological property testing. Unconfined compressive strength (UCS), hydraulic conductivity and microstructural tests were performed on CPBs that were made with various mixing times and cured for different times (up to 90 days). Monitoring experiments were also carried out on CPBs prepared with various mixing times. The results obtained indicate that the mixing time significantly affects the rheological, mechanical, hydraulic and microstructural properties of CPB. Moreover, the self-desiccation of CPB is a function of the mixing time. A longer mixing time increased the yield stress and decreased the viscosity. The longer mixing time promoted binder dissolution and hydration in the CPB, which increased the amount of hydration products and decreased the volumetric water. Longer mixing time intensified the CPB self-desiccation, which is beneficial for the early age mechanical strength of CPB. CPB specimens made with longer mixing time experienced a higher strength and elastic modulus due to the generation of more cement hydration products and the reduction of the volume of pores in CPB. A longer mixing time reduced the CPB hydraulic conductivity, due to the refinement of the CPB pore structure. This study provides relevant knowledge and technical information that will contribute to the design of more cost-effective and sustainable CPB structures.