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1 – 4 of 4Md. Tareq Hossain Khondoker, Md. Mehrab Hossain and Ayan Saha
Due to its longer length compared to other construction materials and distinctive stacking patterns, obtaining construction steel bars in congested construction sites with limited…
Abstract
Purpose
Due to its longer length compared to other construction materials and distinctive stacking patterns, obtaining construction steel bars in congested construction sites with limited storage capacity becomes challenging. Lack of storage space in crowded places prompts the need for building steel bar storage choice optimization. Therefore, this study aims to optimize the construction steel bar procurement plan by providing when and how much rebar to order and how to stack different sizes of rebar considering limited storage capacity.
Design/methodology/approach
A novel approach has been presented in this paper by integrating 4D building information modelling (BIM) and mixed-integer linear programming (MILP). This technique uses BIM to retrieve material quantities, including rebar, during the design phase. Following that, activities are scheduled depending on the duration determined by crew productivity data and material quantity. Then, based on the prior price, the price of each unit of rebar is projected for the duration of construction using the exponential smoothing method. After that, the MILP approach is used to generate an optimal steel bar procurement plan for limited storage space following the scheduled rebar-related operations.
Findings
The developed strategy minimizes overall procurement costs and ensures the storage of rebar as per standard guidelines. An optimal rebar procurement and storage plan to construct a six-storied RC frame has been presented in this paper as a demonstrative example to show the effectiveness of the proposed method.
Originality/value
This work partially satisfies a long-sought research need for establishing a comprehensive construction steel bar procurement system, making it a very useful source of information for practitioners and researchers. The proposed method can be used to minimize a key performance limitation that the conventional rebar procurement practice for crowded building sites may experience.
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Md. Habibur Rahman Sobuz, Md. Montaseer Meraz, Ayan Saha, Abu Sayed Mohammad Akid, Noor Md. Sadiqul Hasan, Mizanoor Rahman and Md. Abu Safayet
This study aims to present the variations of optimal seismic control of reinforced cement concrete (RCC) structure using different structural systems. Different third-dimensional…
Abstract
Purpose
This study aims to present the variations of optimal seismic control of reinforced cement concrete (RCC) structure using different structural systems. Different third-dimensional mathematical models are used to examine the responses of multistory flexibly connected frames subjected to earthquake excitations.
Design/methodology/approach
This paper examined a G + 50 multi-storied high-rise structure, which is analyzed using different combinations of moment resistant frames, shear walls, seismic outrigger systems and seismic dampers to observe the effectiveness during ground motion against soft soil conditions. The damping coefficients of added dampers, providing both upper and lower levels are taken into consideration. A finite element modeling and analysis is generated. Then the nature of the structure exposed to ground motion is captured with response spectrum analysis, using BNBC-2020 for four different seismic zones in Bangladesh.
Findings
The response of the structure is investigated according to the amplitude of the displacements, drifts, base shear, stiffness and torsion. The numerical results indicate that adding dampers at the base level can be the most effective against seismic control. However, placing an outrigger bracing system at the middle and top end with shear wall can be the most effective for controlling displacements and drifts.
Originality/value
The response of high-rise structures to seismic forces in Bangladesh’s soft soil conditions is examined at various levels in this study. This study is an original research which contributes to the knowledge to build earthquake resisting high-rises in Bangladesh.
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Pablo Santos Torres, Carlos Francisco Simões Gomes and Marcos dos Santos
The present paper assesses the decision problem of selecting Unmanned Aerial Vehicle Systems (SARP) by the hybrid MPSI-SPOTIS approach for deployment in border control and…
Abstract
Purpose
The present paper assesses the decision problem of selecting Unmanned Aerial Vehicle Systems (SARP) by the hybrid MPSI-SPOTIS approach for deployment in border control and transborder illicit combat.
Design/methodology/approach
By the hybrid MCDA MPSI-SPOTIS approach, and from the database available in Gettinger (2019), models were filtered by Endurance, Range, Maximum Take-Off Weight (MTOW), and Payload, fitting within the classification of Categories EB 0 and 2. Category EB 1 was not considered in this study due to the limited number of models in the data source.
Findings
The use of the Multi-Criteria Decision Analysis (MCDA) tool MPSI-SPOTIS allowed the determination of weights by stochastic criteria, applied in a ranking method resistant to reverse ordering. The application of the method identified the Raybird-3 (Cat EB 0) and Searcher (Mk3) (Cat EB 2) models as the best alternatives. From a proposed clustering, other selection possibilities with close performance in the evaluation were presented. The cost criterion was not taken into consideration due to the absence of information in the data source employed. Future studies are suggested to include criteria related to the life cycle and acquisition cost of the models.
Research limitations/implications
The cost criterion was not taken into consideration due to the absence of information in the data source used. Future studies are suggested to include criteria related to the life cycle and acquisition cost of the models.
Originality/value
This paper aims to propose a technology selection method applied to complex defense acquisitions when multiple factors influence the decision makers and it is hard to obtain a major optimum solution in multitask and multi-mission platform.
The approved methodology of property valuation in Albania evaluates the reference property prices based on the average contractual price of properties sold and takes into account…
Abstract
Purpose
The approved methodology of property valuation in Albania evaluates the reference property prices based on the average contractual price of properties sold and takes into account only factors such as price, square meters of living and location of property. Simple method is the one used on evaluating the reference price for a group of properties with similar characteristics. The purpose of this study is, by building a hedonistic pricing model for apartments in Tirana, to prove empirically that in addition to location, there are other characteristics that affect the value of apartments.
Design/methodology/approach
The capital city is chosen as a case study for the construction of a hedonistic pricing model. In the database were included detailed characteristics of 1,421 apartments. Multiple regression analysis was chosen in this model as a method to test hypotheses about the causal relationship between house value Y and independent variables XS, representing the characteristics of the property. Population equation parameters β0, β1, β2 […], βn. were evaluated by the ordinary least squares method. Selection of α-standard is 5 per cent, taking into account the significant number of observations and the degree of regression freedom.
Findings
Based on this study, it was proved empirically that the characteristics of the apartments as square meters of living, number of rooms, access to parking, furniture, view and surface of living affect their price. As a literature review showed, location is the most important variable that affects the value. Results showed that the marginal effect that the number of rooms has on the apartment value depends on the square meters of living of the apartment. In the same line, the effect of the square meters of living on value depends on the square meters, as the relationship between these variables is nonlinear and depends more on the number of rooms.
Research limitations/implications
It was impossible to find the information on property sales contracts. That is why this study was oriented toward the market and took into account the properties offered for sale at one of the biggest real estate agency “Çelësi”. More accurate information regarding properties characteristics could be obtained. The information was limited and depended on the best apartment characteristics that potential sellers wanted to advertise. On the other side, contractual sales price is oriented by the reference price, so, the applied methodology has resulted in better evaluations of real estate prices, which reflect the market price.
Practical implications
This study is conducted as an applicable research. After analyzing the property valuation system in Albania, the study recommends the change of the method used on apartment valuation. Improvement of the property valuation system requires first of all creation of a complete and updated database for all real estate sales.
Social implications
Property valuation is a very important function of the land administration system which directly affects people’s life. Property evaluation for different purposes like tax evaluation, compensation and expropriation is a process that must be designed using an equal, transparent and well-accepted methodology by all. Promotion of property valuation system development is helpful to various interest groups in society, as it can reduce the risk of investment in this sector and encourages lower rates of interest on loans.
Originality/value
To the author's knowledge, the hedonic model is not applied on the Albanian housing market, thus providing encouragement to deepen the study in this regard. The study is original and has a very important impact on policymakers to change the actual property valuation methodology to obtain more accurate property values.
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