COMPARISON OF BEARING CAPACITY OF FOOTINGS WITH SAME AREA RESTING ON REINFORCED SAND

ABSTRACT: The Paper presented from an experimental study for circular and square footing with same area that resting on sand bed. The steel model footing with 12 cm diameter (113 cm 2 ) and square footing with 10.6 cm width in sand with relative density 60% were used. For reinforced conditions geogrid layers were used. The settlementload responses of the tests were investigated. Results indicated that ultimate bearing capacity increased in square footing in comparison with circular footing, and when reinforcements used with embedment depth (u/D=0.42 or u/B=0.47), the bearing capacity ratio (BCR) was increased greatly in circular footing in comparison with square footing. The BCR increases with increasing the number of geotextile layers for both of the footings (square and circular) but for reinforced conditions the geogrid layers have a better effect for circular footing in comparison with square footing and the rate of increasing BCR for circular footing is higher than square footing

Deploying hybrid modelling to support the development of a digital twin for supply chain master planning under disruptions

Supply chains operate in a highly distuptive environment where a SC master plan should be updated in line with disruptions to ensure that a high service level is provided to customers while total cost is minimised. There is an absence of knowledge of how a SC master plan should be updated to cope with disruptions using hybrid modelling. To fill this gap, we present a hybrid modelling framework to update a SC master plan in presence of disruptions. The proposed framework, which is a precursor to a SC digital twin, integrates simulation, machine learning, and optimisation to identify the production, storage, and distribution values that maximise SC service level while minimising total cost under disruptions. This approach proves effective in a SC disrupted by demand increase and lead time extension. Results show that employing hybrid modelling leads to a noticeable improvement in service level and total cost. The outcome of the new knowledge on using hybrid modelling for managing disruptions provides essential learning for the extension of modelling through a digital twin for SC master planning. We observe that in the presence of disruptions it is more economical to keep higher inventory at downstream SC members than the upstream SC members

Security-constrained unit commitment with natural gas pipeline transient constraints

The interdependencies of power systems and natural gas networks have increased due to the additional installations of more environmental-friendly and fast-ramping natural gas power plants. The natural gas transmission network constraints and the use of natural gas for other types of loads can affect the delivery of natural gas to generation units. These interdependencies will affect the power system security and economics in day-ahead and real-time operations. Hence, it is imperative to analyze the impact of natural gas network constraints on the security-constrained unit commitment (SCUC) problem. In particular, it is important to include natural gas and electricity network transients in the integrated system security because the impacts of any disturbances propagate at two distinctly different speeds in natural gas and electricity networks. Thus, analyzing the transient behavior of the natural gas network on the security of natural gas power plants would be essential as these plants are considered to be very flexible in electricity networks. This paper presents a method for solving the SCUC problem considering the transient behavior of the natural gas transmission network. The applicability of the presented method and the accuracy of the proposed solution are demonstrated for the IEEE 118-bus power system, which is linked with the natural gas transmission system and the results are discussed in this paper.fi=vertaisarvioitu|en=peerReviewed

Urban agrifood circularity: exploring consumable and capital micro circular production loops

The circular economy concept is typically applied at scale, especially for high value products and materials. The dominant manufacturing model is for large global factories with research and practice independent of agriculture. This paper challenges the dominant “big is beautiful” ethos and explores how agricultural and industrial production can operate at local, urban scale with wastes circulating for consumable and capital production. The research case is a UK city where food wastes could be used for food production and beverage production waste could be used to produce building materials. The research explores the industrial symbiosis engineering challenge of small-scale waste conversion and the digital challenge of identifying and measuring waste flows for conversion. In considering waste conversions through local, distributed manufacture this paper also tackles the digital challenge of how to source local, small volume material flow data for optimization. Future potential research avenues of micro manufacture as well as digital twins are discussed

Load eccentricity effects on behavior of circular footings reinforced with geogrid sheets

In this paper, an experimental study for an eccentrically loaded circular footing, resting on a geogrid reinforced sand bed, is performed. To achieve this aim, the steel model footing of 120 mm in diameter and sand in relative density of 60% are used. Also, the effects of depth of first and second geogrid layers and number of reinforcement layers (1–4) on the settlement-load response and tilt of footing under various load eccentricities (0 cm, 0.75 cm, 1.5 cm, 2.25 cm and 3 cm) are investigated. Test results indicate that ultimate bearing capacity increases in comparison with unreinforced condition. It is observed that when the reinforcements are placed in the optimum embedment depth (u/D = 0.42 and h/D = 0.42), the bearing capacity ratio (BCR) increases with increasing load eccentricity to the core boundary of footing, and that with further increase of load eccentricity, the BCR decreases. Besides, the tilt of footing increases linearly with increasing settlement. Finally, by reinforcing the sand bed, the tilt of footing decreases at 2 layers of reinforcement and then increases by increasing the number of reinforcement layers

Modelling soil-vegetation-atmosphere in a field experiment

In this paper, a soil-atmosphere-vegetation interaction, comprised of the state of the atmosphere and its interactions with vegetation in terms of precipitation, wind, temperature, and radiation, is used based on a Finite Element code (CODE_BRIGHT) to predict the slope response to atmospheric actions. For this aim, an atmospheric boundary condition as a flux is applied on the surface of the simulated slope to impose meteorological data that vary in time. At the root zone, a surface flux is applied to interact with the atmosphere flux boundary condition. For the validation purpose, the data from an instrumented slope in Barcelona is utilized. The response of slope to rainfall infiltration and its interaction with the atmosphere demonstrated that vegetation plays a serious role in thermo-hydraulic variables.Postprint (published version

A simulation-optimization approach for integrating physical and financial flows in a supply chain under economic uncertainty

In the last decade, increasing costs and organizational concerns regarding the funding and allocation of financial resources have led to significant attention being given to financial flow and its effects on planning decisions throughout supply chain networks. This study aims to develop a simulation-optimization model to integrate the financial and physical flows in a supply chain planning problem under economic uncertainty. The simulation-optimization model includes a mixed-integer linear programming model and a simulation-based optimization model that are connected through an iterative process. The economic value added (EVA) index is used to measure the financial performance of the supply chain. This study extends the literature on two research domains namely supply chain planning and finance and simulation-optimization modelling for supply chain management. The proposed model applies a scenario approach to cope with economic uncertainty in the supply chain. To demonstrate the efficiency of the proposed model, the performance of the proposed model in solving a test problem from the recent literature is compared with the performance of a conventional simulation-based optimization and mixed-integer linear programming approaches. The results of the study show a minimum of 6% improvement in the EVA obtained from the proposed simulation-optimization model compared to the EVA obtained from the simulation-based optimization model in all the studied scenarios. Moreover, the standard deviation of the EVA obtained from the proposed simulation-optimization model is at least 69% lower than the EVA obtained from the mixed integer programming model in all the studied scenarios. This shows that the proposed simulation-optimisation approach is more robust to economic uncertainty than the mixed-integer linear programming approach