Economic Design Approach Research Articles

Capacity Spectrum-Based Retrofitting Method and Quick Design for Viscously Damped Structures by Utilizing the Concept of Uniform Damping Ratio

Viscous dampers have proven to be effective in enhancing the seismic performance of existing structures. Despite this, there is still a need for rapid and simplified design methods and formulae for viscous dampers that can take into account the elastic–plastic performance of structures. This study introduces a retrofit design method for existing structures using viscous dampers, based on the concept of uniform damping ratio (UDR), with the aim of fully utilizing each damper. The UDR concept assumes that each damper in the structure provides the same UDR when subjected to seismic excitations of identical intensity. In this method, the first step involves defining the equivalent damping ratio (EDR) of the damper. Then, based on the capacity spectrum of the structure, the response mitigation ratio can be determined, which helps to determine the additional EDR required from the dampers. Once the UDR and additional EDR from the viscous damper have been determined, the parameters of the dampers at each story can be rapidly obtained. To demonstrate the effectiveness of this method, a six-story reinforced concrete frame was utilized as a benchmark structure. A comparison between this UDR-based approach and a traditional design approach was also conducted. The study findings reveal that the UDR concept enables the maximum utilization of energy dissipation capacity of viscous dampers installed in the structure, leading to a more effective and economical design approach.

Formation of the architectural space of health care facilities based on landscape design

Architecture is gradually changing along with the development of society, its changing perceptions of beauty, strength, usefulness, as well as the growing need for comfort, aesthetics, the ideal environment. For a long time, the architecture of health care facilities was perceived and, accordingly, mechanically designed exclusively as a kind of technically necessary shell to ensure the treatment of the impersonal mass of the population. This approach was due to the acute and rapid need for a quantitative supply of medical institutions to a large number of people in large areas. This is what happened in the last century in the post-Soviet countries - standard projects of medical institutions were "cloned" everywhere, which were integrated into the urban environment by huge industrial-panel arrays without regional, cultural and aesthetic connection with "genius loci" and urban context. Do we have the right to condemn this large-scale approach that prevailed in the twentieth century? No. At one time, he made it possible to resolve the important issues of providing medical care to the majority of the population of the Soviet Union. Thanks to the massive and economic industrial design and construction approach, Ukraine has received an extensive urban network of various health care facilities, which continue to perform their functions, accepting the harsh challenges and trials of global pandemics and epidemics. The main problem is that with the acquisition of sovereignty in Ukraine began protracted political-oligarchic clan "internecine wars", which for decades froze attention to improving, modernizing, updating and developing the architecture of health care facilities. A significant part of Ukrainian hospitals is in a condition that not only does not meet sanitary and other requirements, but even threatens the health and lives of patients and staff. But it is not customary to talk about it. The Soviet mentality, enshrined in our subconscious, forces everyone in their place to report on the order, on compliance, on the implementation of plans. Despite the long-standing disregard for the problems and issues of compliance of domestic medical architecture with world standards, the powerful and once the world's best "machine" continued to perform its functions, inertially moving down from its pedestal. But today, in 2021, we are frantically approaching the foot of the new "rock", which embodies all the latest advances in health care and which the world's leading countries have gradually, step by step, overcome with long-term state plan for the development of medicine and with periodic reforms in the medical field.

BRB system stability considering frame out-of-plane loading and deformation zone

A simple and economical design approach is described for a BRB system, consisting of a BRB within a steel frame, subject to in-plane and out-of-plane seismic displacements. The approach avoids out-of-plane system or brace instability while allowing large frame out-of-plane deformations and desirable BRB axial performance. It also limits the compressive/tension force ratio. It is based on the simple concept that a brace will be stable with two moment-releases (hinges) but that an out-of-plane buckling mechanism may occur with more than two. The hinges are detailed as specified deformation zones (SDZs) at the brace ends. The hinges use a plate which can yield about its weak axis during out-of-plane movement. Simple methods to assess the stability of the brace itself (between hinges) are developed, an example is provided illustrating how the monotonic deformation demand of the simple plate hinge can be assessed, and detailing recommendations are made to restrict the deformation of the boundary elements at the brace ends.

Seismic response of multi-span continuous irregular bridges using displacement-based and conventional force-based methods

In the recent years, the displacement-based seismic design (DBD) method of structures has been recognized as the alternative design method to the conventional force-based seismic design (FBD) method. The problems inherited in the FBD method are mostly overcome by the DBD method as it better correlates the structural damage with displacement-based quantities. In this study, the seismic response of multi-span bridges with varying number of spans and unequal pier heights was evaluated using the DBD method and compared with the conventional FBD method. Two approaches were employed in the DBD method, such as the traditional direct displacement-based seismic design (DDBD) approach and the proposed approach in this study entitled as alternative-to-direct displacement-based seismic design (ADBD). For seismic evaluation of the bridge structures with the FBD method, acceleration response spectra as suggested in the Bangladesh National Building Code were used; while in the DBD method, displacement response spectra for different damping ratios were developed keeping consistency with the above-mentioned design acceleration spectra. Five bridge models were used in the analysis to compare the seismic response in both the longitudinal and transverse directions taking into account the number of spans and height irregularity in the bridge models. Numerical analysis showed very obvious results that the base shear calculated by both approaches of the DBD method is found to be smaller than the FBD method indicating that an economic member section be attained for meeting the same design objective. More specifically, the ADBD approach provides the design professionals a more conservative design approach in compared with the DDBD approach keeping an economic design approach comparing with the FBD method.

Development of Completely Automated Poly Potential Portable Potentiostat

Various research activities related to profiling chemicals employ detection or measurement of the response from a specimen in terms of electric fields or currents. Hence, a portable poly-potential device forms one of the necessary measuring equipment essential to these domains. This work aims to propose a Poly-Potential Portable Potentiostat (P4), that can perform electrochemical analysis of solutions through easily integrable data-acquisition hardware and flexible software post-processing. The P4 device is based on a commercial development board, which provides an analog front-end (AFE) for working with 2-lead and 3-lead amperometric cells. An economical and portable design approach is prioritised while keeping the basic functions of the research-grade commercial instruments. A novel technique of dynamically changing the bias and reference potential is used to achieve a finer resolution, enabling qualitative estimation. P4 works by performing detailed mathematical post-processing on-board and therefore relies on hardware integrity as much as on software flexibility. Calibration of P4 was done using a standardised solution to function independently of any external hardware or software tools. P4 makes electrochemical analysis truly portable in remote or resource-constrained applications.

Cradle to Cradle and Whole-Life Carbon assessment – Barriers and opportunities towards a circular economic building sector

The general awareness of climate change has been increasing steadily while buildings continue to be the main contributors to greenhouse gas emissions. To address the need for change in the building industry and transform its hazardous impacts on the environment to a positive footprint, circular economic design approaches and Whole-Life Carbon (WLC) assessment have been introduced. This paper analyses the main barriers for a successful implementation of the regenerative Cradle to Cradle (C2C) concept and WLC evaluation, identifying the lack of unified and measurable framework along with the deficiency of detailed case studies and post occupancy evaluation. In the context of the increasing demand for carbon accounting, obtaining comprehensive information on embodied carbon in buildings is challenging despite the existing Life Cycle Assessment structure. To link theory with practice, the paper discusses the London School of Economics Centre Buildings Redevelopment by RSH+P as case study. It reveals barriers and opportunities for WLC evaluation as well as the potential of life cycle cost optimization in environmental and economic terms.The paper concludes with a reflection on how the certification of materials through material passports may not only achieve a higher transparency but lead to a circular economic building industry by comprehensive WLC assessment and a closer implementation of reversible building design corresponding to the C2C principles. The potential of combining WLC evaluation with C2C strategies and translating them into a comprehensive, unified assessment framework for a circular building sector is identified.

Parameter and Tolerance Economic Design for Multivariate Quality Characteristics Based on the Modified Process Capability Index With Individual Observations

The process capability index (PCI) is widely used in an on-line quality control stage for measuring and controlling the quality level of a production process. The calculation of PCI requires a large number of samples, but in the off-line quality control stage, a certain production process in off-line quality control stage only has a few individual observations. From the perspective of quality loss and tolerance cost, this paper proposes a parameter and tolerance economic design approach for multivariate quality characteristics based on the modified PCI with individual observations. The response surface models of mean and variance are constructed using individual observations, and exponential models are fitted according to the tolerance cost data of design variables. A modified PCI is proposed with the consideration of three types of quality characteristics. The optimal design variables and tolerances are obtained by a comprehensive optimization model that is constructed based on the proposed PCI. An example of an isobutylene-isoprene rubber (IIR) inner tube is used to (i) demonstrate the implementation of our proposed approach, (ii) improve the PCI value and reflect the sensitivity of the deviation between process mean and specification, and (iii) reduce the risk of increasing cost of quality caused by replicated experimental design and some other unknown reasons.

Economic design under gamma shock model of the control chart for sustainable operations

The non-uniform sampling scheme and economic statistical design approaches have been successfully applied to determine three parameters of x-bar control charts to monitor a manufacturing process with increasing hazard functions for the last three decades. Nevertheless, a primary assumption for these cost models is that measurements within a sample are independent. However, the conventional supposition may significantly underestimate the type I error probability for the x-bar control chart. Hence, we develop a cost model that combines different researches with the multivariate normal distribution model that given the maximum probability of type I error and the minimum value of power. The optimal parameters of non-uniform sampling interval x-bar control charts are used for the measurements within a sample being correlated. In addition, an industrial example is applied to indicate the solution procedure. Sensitivity analysis is accompanied with input parameters including correlated coefficients as well as process and cost parameters of the model are performed. The genetic algorithm is adopted to reveal the optimal solution of the economic design. The method proposed can be used on related industries to achieve the ability of production monitoring and cost reducing. The human resource consuming and the amount of scraps will be avoided toward the conclusive goals of economic benefit, environmental benefit and social benefit.

A performance-based method for the design of drainage trenches used to stabilize slopes

Drainage trenches are widely used as a measure for slope stabilization. Their effect is generally quantified in terms of a safety factor against a possible collapse mechanism of the slope. A more rational and economical design approach consists in admitting the occurrence in some time intervals of limit conditions in the slope, and evaluating the performance of the slope in terms of accumulated permanent displacements of the unstable soil mass. The resulting displacements should avoid the occurrence of significant damage and preserve the serviceability of existing structures. In this context, a new method is proposed in the present paper for the design of drainage trenches used to control the mobility of translational landslides periodically activated by rainfall. This method is based on some analytical equations that relate rain to the groundwater regime as modified by the trenches, and a simple sliding block model to evaluate the landslide displacements. The proposed method also accounts for the delay of the hydraulic response at different depths. The above-mentioned equations are validated by several comparisons with numerical results obtained using a finite element code or published in the literature. Finally, the method is applied to some case studies to show the effectiveness of the drainage trenches to control the landslide mobility owing to rainfall.

Performance-based plastic design approach for multi-story self-centering concentrically braced frames using SMA braces

Self-centering concentrically braced frames (SCCBFs) are emerging as one of the high performance seismically resistant framing systems, known for the capability of controlling peak seismic demands and eliminating residual deformation. In the process of developing SCCBFs, shape memory alloys (SMAs) are deemed as the potential candidate for the key component of SCCBFs, due to the excellent superelastic capacity and desirable flag-shape hysteresis. For the SCCBFs using SMA braces (SMABs), an economical and effective design approach based on the performance-based plastic design was recently derived. This study aims to extend the ad hoc design approach to low-to-high rise multi-story SCCBFs using SMABs, and to examine its generality. As such, the seismic performance of four SCCBFs with various story numbers was intensively analyzed by subjecting them to ground motion records corresponding to design-basis earthquake. The analysis results show that all the resulting frames were capable of coinciding well with the prescribed targets of peak interstory drift ratios and ductility demands. In addition, the structures returned to at-rest positions without producing residual deformation after earthquake events. Therefore, this study successfully validates the applicability of the ad hoc design approach to SCCBFs with various story numbers.

Multi-criteria optimization of concrete arch dams

In this study, multi-criteria shape optimization of an asymmetrical doublecurvature arch dam is presented. Simultaneous cost minimization of dam construction and maximum allowable tensile stress are investigated for an economical and safe design approach in the current study. Pareto front method was used to balance both the economy and safety of the design simultaneously, which can be dicult for both analysts anddecision-makers. A non-dominated solution based on the important parameters of dam analysis and design is presented. To help decision-makers in their decision, two diff erent methods are proposed. These methods for the case of an arch dam are Lombardi coecient and equilibrium point methods. The obtained results indicate that these two methods can be helpful for designers without experience and information of previous designs.

Effectively designed shell‐tube heat exchangers considering cost minimization and energy management

AbstractCost optimization, which is expressed as a set of analytical variables, is a key objective in economic design approaches of shell‐and‐tube heat exchangers. This study has provided new design techniques based on tube bundle effect on the economic optimization design of shell‐and‐tube heat exchangers. Also the objective of this paper is to develop the cost estimating for the new modified shell‐and‐tube heat exchangers by introducing new objective functions. According to the results the best configuration choice will obviously be the one with the least irreversibility, that is, with the lowest exergy destruction rate and lower annual capital cost. Also, the combined reduction of annual capital investment and operating cost by the new design technique led to a decrease in the overall costs of about 10% to 24% in comparison with original design. So the proposed design technique shows potential for improvement and economic optimization of shell‐and‐tube heat exchangers.

아치형 조립식 PC 탄약고 설계 및 방호성능 평가

본 연구는 수치해석과 폭발 실증시험을 통해 조립식 PC 아치 탄약고의 설계 및 시공도면을 제시하였다. 제안된 탄약고의 방호성능은 미군의 UFC 3-340-02와 한국군의 국방 군사시설 설계기준(탄약고 설계지침)에서 제시된 최대 회전각도로 판별하였다. 아치형 탄약고의 기초설계를 위해 곡면형태인 반원형과 오발형에 대하여 폭발하중에 대한 방호성능을 수치해석을 통해 살펴본 결과 오발형이 타원형에 비하여 지점회전각이 적어 전반적으로 방호성능이 뛰어남을 확일 할 수 있었다. 이를 통해 아치형 조립식 PC 탄약고의 설계안 및 시공도를 제안하였으며, TNT 133.75kg을 구조체 벽체로부터 00m 이격하여 폭발시켜 실제 시공된 탄약고에 대한 방호성능을 검증하였다. 결론적으로, 본 연구에서 제안된 탄약고는 충분한 방호 여유력을 확보하고 있는 것으로 확인할 수 있었다. 향후 이러한 방호 여유력을 고려하여 재료의 절감을 통한 보다 경제적인 탄약고 설계도 가능할 것으로 사료된다. This study suggests the design and assembly drawing of the prefabricated precast concrete arch ammo magazines using the numerical analysis as well as the explosion verification test. The protective capacity of the proposed magazines is identified with the maximum support rotation angles measured by explosion verification tests according to the U.S. Unified Facility Criteria 3-340-02. Using numerical analysis, it is examined that oval-type members are better than the semi-circle ones in terms of protective capacity. Based on this numerical results, the design and assemble drawing for the prefabricated precast concrete arch ammo magazine are developed. It is identified that the structure constructed by invented design and assembly drawing has enough protective capacity against blast pressure caused by 133.75kg TNT explosion. The detonation point cannot be open due to the military security. In sum, it could be concluded that the ammo magazine proposed in this study has reliable protective capacity with enough redundancy. The redundancy means that there are more economic design approach with reducing the curved wall thickness.

An economic-statistical design of the joint and S control charts with double sampling and variable sampling intervals

A combination of double sampling and variable sampling interval (DSVSI) charts can increase the efficiency of signaling small shifts . This study proposes an economic-statistical model for designing joint DSVSI and s charts. The proposed approach uses the economic model developed by Duncan in 1956. Research results indicate that the economic-statistical design of the joint DSVSI and s charts outperformed traditional economic design approach in detection abilities of process shifts; variable cost (a2), expected costs resulting from defective products when the process was in control (C0), and the expected number of assignable causes (λ) have the major influence on cost E(C′); deviations (δ, γ) significantly influenced cost E(C′); and statistical limitations () do not substantially affect cost E(C′).

ECONOMIC-STATISTICAL DESIGN APPROACH FOR A VSSI X-BAR CHART CONSIDERING TAGUCHI LOSS FUNCTION AND RANDOM PROCESS SHIFTS

Economic design approaches of control charts are commonly based on the assumption that various cost parameters values and the occurrence risk of assignable causes have to be a priori known with precision. However, in real operative contexts, such parameters can be really difficult to accurately estimate, especially considering costs arising from out-of-control conditions of the process. As consequence, pure economic design approaches can involve chart schemes with low statistical performance. To overcome such limitation, it is herein proposed a multi-objective economic-statistical design approach for an adaptive X-bar chart. In particular, such approach aims at the minimization of both the total quality related costs and the out-of-control average run length, in such a way assuring an optimal trade-off between economic and statistical performance of the related control procedure. Moreover, for a robust design approach, the mean shift is considered as a random variable. A mixed integer nonlinear constrained mathematical model is formulated to solve the treated problem, whereas the Pareto optimal frontier is described by the ε-constraint method. In order to show the employment of the proposed approach, an illustrative example is developed and the related considerations are given. Finally, some sensitivity analysis is also performed to investigate the effects of operative and costs parameters on chart parameters.

Practical solution to attitude control within wide envelope

Purpose – This paper aims to present a fast, economical and practical attitude control design approach for flight vehicles operating within wide envelopes. Design/methodology/approach – Based on a linear disturbance observer, an enhanced proportional-derivative (PD) control scheme is proposed. Utilizing the data from the onboard gyro, the observer can treat the entire response of the system, with the exception of the control term, as a disturbance, and use the estimation of the disturbance to cancel out this response and thereby to effectively simplify the control channel. Using the stability margin tester, the explicit graphical tuning rules are given in a consistent way for the longitudinal dynamics based on the induction method. Mathematical simulations are performed for a highly maneuverable flight vehicle to test the proposed method, which are compared with the traditional PD and H8 control algorithms. Findings – The proposed strategy for attitude control can be reformulated as a static-dynamic contr...

Quality of Service on Queueing Networks for the Internet

Most studies of resource allocation mechanisms in Internet traffic have used a performance model of the resource provided, where the very concept of the resource is defined in terms of measurable qualities of the service such as utilization, throughput, response time (delay), security level among others. Optimization of resource allocation is defined in terms of these measurable qualities. One novelty introduced by an economic mechanism design approach is to craft a demand-driven system which takes into account the diverse QoS requirements of users, and therefore, uses multiobjective (utility) optimization techniques to characterize and compute optimum allocations. Economic modelling of computer and communication resource sharing uses a uniform paradigm described by two level modelling: QoS requirements as inputs into a performance model that is subject to economic optimization.

Design of embankments supported on controlled modulus columns

<p>In recent years, the use of controlled modulus columns (CMC) to support road or rail embankments over soft ground at bridge approaches has gained popularity in Australia. Despite their higher cost per unit area of ground treatment compared to other methods, CMC are often the preferred method of treatment when time is of the essence. CMC enable accelerated construction of bridge abutments due to their speed of installation and ability to limit lateral soil and abutment pile movements during embankment construction. In Australia, most CMC supported embankments to date have been designed using similar principle as piled embankments, with the columns treated as structural elements to take all the applied loads. The authors believe that there is scope for CMC to be more cost-effective if they are designed to function as geotechnical elements.</p><p>This paper examines a number of CMC design issues, including the effect of columns stiffness and spacing on settlement reduction, the need for load transfer platform over the columns, and what if the columns crack when their bending moment capacity is exceeded, and do columns need to be reinforced. An economic design approach is recommended and two case studies are provided to illustrate the use of CMC to support bridge approach embankments.</p>

Pseudo-plastic moment resistance of continuous beams with cold-formed sigma sections at internal supports: A numerical study

Most thin-walled steel sections exhibit a softening moment–rotation characteristic under bending, and as a result, an elastic method of analysis and design is usually recommended for continuous beams with this type of section. A more economical design approach, the pseudo-plastic design method, has been proposed to allow for the development of moment redistribution in the system. One key to this design method is to determine the pseudo-plastic moment resistance (PPMR) at internal supports. This paper reports a numerical study on the pre-buckling, buckling, post-buckling and post-failure behaviours of continuous beams with cold-formed sigma sections near internal supports, based on which the PPMR was derived. Detailed information on input parameters required in the numerical modelling process, such as the choice of element type, element size, loading and boundary conditions, material properties, initial imperfections and the selection of solution scheme, are presented. The developed numerical model was validated by 20 laboratory tests. It was then applied to carry out parametric studies to investigate the influence of geometric dimensions (e.g., the depth and the thickness of the cross-section and the span) on the failure mode, the ultimate moment resistance and the PPMR of sigma beams at internal supports. Numerical results of ultimate moment resistance were compared with theoretical predictions obtained using two codified methods, i.e., the Effective Width Method (EWM) and the Direct Strength Method (DSM). The difference in predictions from numerical simulations and codified methods was studied, which was followed by suggestions for improvement in using codified methods. Finally, a semi-empirical approach has also been proposed to determine the PPMR of cold-formed steel Sigma beams at internal supports.

Limits of Design for Recycling and “Sustainability”: A Review

Metals and materials play a pivotal role in society as their properties impart unique functionality to engineered structures and consumer products. Metals are theoretically infinitely recyclable; however, the functionality and design of consumer product complicate recycling due to their ever more complex structures producing un-liberated low grade and complex recyclates. Metallurgical smelting ingenuity, good technology and intelligent use of thermodynamics and transfer processes gets metallurgists and recyclers a far way down the path of creating high recycling rates from a large range of primary concentrates and recyclates. However, the 2nd Law of Thermodynamics teaches us the practical limits of recycling in terms of entropy creation, which is determined by the complexity of the recyclates and hence to the economics of processing/technology and metal/energy recovery. The usual simple accounting type tools do not rise to the challenge. Therefore, a key issue for the creation of “sustainable systems” and hence the minimization of waste (or in other words achieve high recycling rates) is the creation of optimal industrial ecological systems with optimally linked Best Available Techniques (BAT). This must maximize the recovery of materials from ores and recyclates within the boundaries of consumer behaviour, product design/functionality, thermodynamics, legislation, technology and economics. Examples will show how recyclate quality/grade predicted by recycling models affects entropy creation, while also reviewing various published methodologies. This paper shows that simulation models are a prerequisite to designing “sustainable” systems as these can predict recyclate grade/quality/losses/toxicity of streams, the link to entropy and economics and the realization of company ideals and mission statements in this regard. In other words, to dematerialize society requires detail input by engineers, their predictive tools and economic based design approaches to engineer a sustainable future.