Vol.4,No.1,2024-Table of Contents
- OPEN ACCESS ARTICLE
- Application case of laminated bamboo lumber structure – Building of Sentai Bamboo Research Center
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000043 Online published:2024-6-1
- Abstract Laminated bamboo lumber (LBL) is an engineered bamboo product that provides consistent and reliable mechanical properties for structural applications while offering options for green, environmentally friendly and sustainable development. This paper presents a significant and novel case study highlighting different phases such as analysis, design and construction of a three story office building in which LBL has been used as the main building material. In this building, the main components are prefabricated and then assembled on site making the construction process fast and efficient. Hand calculation techniques were combined with finite element modeling to accurately and efficiently determine the dimensions of components. At present, the design of engineered bamboo structures is based on the standards of wooden structures, but with the gradual increase of engineered bamboo structures, it is important to develop design standards for engineered bamboo.… More
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- Thermal insulation performance of non-load-bearing light gauge slotted steel stud walls
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000042 Online published:2024-5-31
- Abstract Light gauge steel stud walls have been widely used in buildings as load-bearing members. But if used as non-load-bearing walls, more rows of perforations can be placed on stud webs and then the thermal bridge effect can be reduced. Experiments on six non-load-bearing light gauge slotted steel stud walls were conducted using a calibrated hot box. The temperatures of the steel studs and gypsum plasterboard were monitored for subsequent analysis of thermal bridging. The effects of parameters (number of rows of perforations, stud web height, and the ratio of window area to wall area) on the insulating capacity of the wall were identified and analyzed. Thermal transmittance decreases by 18.5% and 29.6% for specimens with 3 and 7 rows of perforations in comparison with the specimen without perforations, while it decreases by 29.8% and 42.7% respectively for 150 mm and 200 mm thick walls compared with that of the 100 mm thick wall. However, thermal transmittance increases obviously for the wall with a window opening relative to the wall without a window opening, reaching 14.7% in this test since more studs are placed around the window opening. A three-dimensional finite element (FE) model of the wall was developed and validated against experimental results, and then was used for parametric studies. A general method of calculating the thermal transmittance of the light gauge slotted steel stud wall was suggested based on the experiment and the FE model results, which can consider influences of wall thickness, web perforations, window openings, and thermal properties of materials.… More
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- Experimental, theoretical and numerical study on the shear stress of adhesive layer in FRP-bamboo scrimber composite beams
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000041 Online published:2024-5-31
- Abstract The adhesive layer is an important factor affecting the mechanical properties of FRP- bamboo scrimber composite beams (FBSCB). However, studies on the interfacial shear stresses in the adhesive layers with both ends of FRP and bamboo scrimber beam aligned have been rarely reported. To this end, a two-parameter theoretical calculation model and a finite element model (FEM) based on cohesive zone model were hereby established to solve for the adhesive layer interface shear stresses, which was verified by four-point bending experiments. The results show that both the two-parameter theoretical model and the FEM can effectively compute the shear stress of the adhesive layer. Meanwhile, the FEM simulation results not only reflect the detailed changes of the shear stress, but also provide a better analysis of the shear stress at the adhesive layer with a small fluctuation range. There are three zones of shear stress at the adhesive layer of FBSCB under four-point bending load, i.e., the bending and shearing zone, the transition zone and the pure bending zone. In the bending and shearing zone, the shear stress of the adhesive layer interface increases 2.61 times and 2.5 times, respectively when the thickness and elastic modulus of FRP increase three times. However, the stress remains constant at zero in the pure bending zone.… More
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- Study on the Permeability and Mechanical Properties of Sandy Soil Under Carbon Fiber-Based Urease Mineralization
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000040 Online published:2024-5-31
- Abstract In recent years, soil solidification by EICP method is a green and environmentally friendly foundation treatment technology that has become popular in the field of geotechnical engineering. Compared with the traditional chemical induction method and the MICP method, the EICP method is not easily restricted by environmental factors associated with engineering geological problems and is green and environmentally friendly with lower cost. In this paper, a study was carried out to improve the seepage-mechanical properties of sandy soils by the EICP method. First, soybean urease solution extraction and its performance optimization methods were explored. Tests were conducted to compare urease extraction and detect activity. The activity of urease was 7.1% higher in deionized water than Laoshan mineral water. Second, the EICP grouting mineralization test was performed by using the carbon fiber reinforcement method. The CaCO3 content, unconfined compressive strength, porosity, permeability and other indicators of the sandy soil were systematically analyzed, and microscopic tests were conducted. The test results showed that after carbon fibers were added to the sand, the mineralization effect of EICP led to the precipitation of CaCO3 that adhered to the surfaces of sand grains and fibers and filled and cemented the pores between sand grains, which improved the integrity of the spatial structure and formed a stable solid sand-fiber monolithic composite structure. When the carbon fiber content was 1.2%, all aspects of performance were optimum. The above test results showed that the carbon fiber-based EICP mineralization method could effectively inhibit the brittle failure and improve the permeability and mechanical properties of sandy soil. This method has good application prospects and development potential for use in engineering geology.… More
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- Effects of aluminum alloy constitutive models on the behavior of concrete-filled aluminum tubular stub columns under axial compression
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000039 Online published:2024-5-31
- Abstract This study aims to examine the effects of various aluminum alloy constitutive models on the behavior of concrete-filled aluminum tubular stub columns under axial compression. The bi-linear model with hardening, the Baehre model, and the Ramberg-Osgood (R-O) model, which follow the European standard (EC9) were analyzed and compared in terms of their ability to describe the stress-strain behavior of aluminum alloy tensile coupons over the full range, and their respective application scenarios were discussed. A total of 74 sets of experimental data results were collected to examine the effects of these three models on the ultimate load of concrete-filled aluminum tubular stub columns. Furthermore, a full-scale model was constructed to analyze the effect of the hardening exponent n in the R-O model on the load-displacement curves. The results show that, apart from the bi-linear model with hardening, the other two aluminum alloy constitutive models are capable of accurately predicting the stress-strain behavior of aluminum alloys throughout the full range. The accuracy of the R-O model is significantly influenced by the calculation methods of n. The Baehre model is found to be more suitable for non-heat-treated aluminum alloys. The simulated ultimate load values obtained from the three constitutive models fall within a deviation range of ±10%, indicating their suitability for practical engineering applications. Among the three models, the R-O model exhibits the highest stability, as changes in the hardening exponent n do not affect the ultimate load but have a significant effect on the load-displacement curves beyond the ultimate load.… More
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- Bond behavior of CFRP-strengthened steel structures and its environmental influence factors: a critical review
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000038 Online published:2024-5-31
- Abstract Adhesively bonded carbon fiber-reinforced polymer (CFRP) systems have shown great promise for strengthening damaged steel structures, offering potential enhancements in the longevity of steel structures. However, the degradation of bond performance of CFRP under harsh environments remains a critical concern for researchers and engineers, as it may significantly impact the efficiency and durability of bonded CFRP strengthening systems. This paper presents a comprehensive review of the impact of key characteristics of bonded joints, such as the CFRP modulus, adhesive performance, bond length, adhesive layer thickness, and bond joint geometry, on the bonding performance of CFRP strengthening systems. Additionally, the influences of environmental factors, including elevated and sub-zero temperatures, moisture, corrosion, humidity, wet-dry cycles, ultraviolet radiation, and freeze-thaw cycles on the bond behavior, were also reviewed. By synthesizing and analyzing existing research insights into the effects of reinforcement materials, bond joint design parameters, and environmental factors on bonding performance, this review article attempts to enhance practitioners' understanding of bond behavior in this field and also provides guidance for future research.… More
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- Progress on the connection performance of steel-engineered bamboo beam-column connections under cyclic loads: a review
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000037 Online published:2024-5-31
- Abstract Bamboo is a great building material due to its low carbon and environmental friendless. The connection performance of beam-column joints had an impact on the seismic performance of the whole structure. The beam-column connection performance is critical in earthquakes. Steel-engineered timber connections have good seismic properties, and the properties of bamboo and timber are very similar. Therefore, the form of wood structure connection can be used in bamboo structures. The type of member materials used and the connection forms applied determine the structure elastic behavior. Common engineered bamboo has been introduced, and the current connection form of engineered timber has been summarized in this paper. Secondly, research on the indicators of connection performance under cyclic loads has been introduced, including damage forms, strength, ductility, and energy dissipation capacity. Thirdly, the traits of various types of connections are presented, and this paper could be taken as a reference for future studies on connections in steel-engineered bamboo structures.… More
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- A logical retrofit strategy optimization framework for resiliency bridge infrastructure management considering life-cycle cost
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000036 Online published:2024-5-27
- Abstract Bridges play an important role in providing essential services to communities as one of the most critical components of transportation infrastructure. In this regard, selecting reliable, robust, and efficient indicators is necessary to prepare a disaster management strategy. This study presents a multi-objective optimization framework for decision-makers to find the most optimal retrofit strategies that satisfy a given threshold of functionality/Resilience (R) while minimizing a structure's Life-Cycle Cost (LCC). Accordingly, various retrofit strategies include different materials (steel, Carbon Fiber Reinforced Polymer (CFRP), and Glass Fiber Reinforced Polymer (GFRP)), thicknesses, arrangements, and timing of retrofitting actions. In each scenario, the fragility curves are derived through nonlinear time-history Incremental Dynamic Analysis (IDA) to evaluate the LCC and resilience. In the subsequent step, the LCC analysis is conducted, considering the proposed formulation of multiple occurrences of seismic events, which incorporates the effects of complete/incomplete repair actions of damage conditions induced by previous seismic events. This study employs an elitist Non-dominated Sorting Genetic Algorithm II (NSGA-II) to identify the optimal set of solutions. The various aspects of the optimal retrofit strategies are thoroughly investigated and discussed for a bridge as a case study infrastructure. Results show that the considered objectives lead to reasonable and sense-making retrofit strategies.… More
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- State-of-the-art review on steel-concrete composite walls
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000035 Online published:2024-5-27
- Abstract Steel-concrete composite walls, valued for their capacity to combine the strengths of steel and concrete, have become a prevalent construction choice. During the past few decades, the performance of steel-concrete composite walls has been studied by means of structural tests, theoretical analysis, and numerical simulation. Different types of steel-concrete composite walls have been proposed by researchers to satisfy miscellaneous structural requirements. Meanwhile, new forms were continually being developed to further improve the mechanical performance. This review paper examines research conducted over the past few years on these versatile structural elements. The paper categorizes steel-concrete composite walls according to the arrangement of steel plates and concrete, along with the configurations of steel plates. It delves into the unique characteristics of each type and analyzes their performance under various loading conditions, including axial, cyclic, shear, fire, dynamic, impact, and joint loads. Additionally, existing design recommendations for these walls are summarized. To conclude, the paper offers insights into potential future developments in steel-concrete composite wall technology.… More
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- Comparison of using two LCA software programs to assess the environmental impacts of two institutional buildings
- Sustainable Structures Vol.4,No.1,2024 DOI:10.54113/j.sust.2024.000034 Online published:2024-5-27
- Abstract The current trends in climate change have captured the attention of stakeholders across multiple industries, including the building sector. With the introduction of innovative building materials such as mass timber products (MTPs), it has become essential to evaluate their environmental performance. In response, a variety of life cycle assessment (LCA) software programs are available to meet this need. However, it is crucial to understand how different LCA software and databases might influence the results. This study was aimed at exploring the impact of two widely used LCA software programs, SimaPro and Athena Impact Estimator, on LCA results. Two buildings were employed to conduct this study, a traditional institutional building and a mass timber building currently under construction. By comparing the numerical outputs from both software programs, it was discovered that while both could reach similar conclusions regarding the environmental impacts of a building, their use is limited to comparative purposes only. The software programs produced distinct numerical values in their outputs and attributed the sources of impacts differently, indicating they cannot be used interchangeably. However, either SimaPro or Athena Impact Estimator was suitable for estimating the global warming potential of a building during stages A1 to A3.… More
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