Papers by Keyword: Cost

Abstract: A well-designed structure that goes through proper construction stages will reduce the risk of losses that may be apparent in construction work. Consequently, the development of BIM technology becomes a solution for achieving it through the ability of information integration that it offers. In this study, analysis and design of a multi-tower structure are conducted with BIM usage during the design process. The study is carried out by redesigning two structures that have been separately designed previously, namely Tower Laboratory and Hangar Laboratory, with a skybridge connecting them. The study is started by joining both structures without any changes in element sizes to compare the changes in the structural behavior consistently. The study is then continued by doing design evaluations on the connected structure with response spectrum and time history analyses. BIM integration is then used to obtain concrete and bar volumes necessary for cost calculations. The results show that two separate structures will have changes in their dynamic behaviors when they are connected, which will affect their design especially in resisting lateral forces like earthquake load. Conclusively, a maximum change of 27,96% for Tower Laboratory and 31.77% for Hangar Laboratory was found when the two structures are subjected to Kocaeli ground motion with skybridge connecting them. Efficiency of total structural cost by 2.2047% was achieved for Tower Laboratory and 0.5523% for Hangar Laboratory with the use of time history analysis. Further, this study shows the potential of BIM in helping structural designs process despite its imperfections and further developments needed.

Abstract: Abrasive Waterjet Machining (AWJM) has significant advantages, such as being environmentally friendly, used for machining hard-to-cut materials, and do not cause a heat-affected zone. More machining tests are needed to understand the concept of material machinability in AWJM to increase process flexibility and produce parts with higher productivity, better accuracy, and surface quality. This paper presents drilling and slotting experiments through different metallic materials at fixed machining conditions to evaluate their machinability using AWJM. It introduces new machinability indices that arrange the tested materials concerning their machinability rating. Drilling indices include volumetric removal rate (VRR), penetration rate (PR), specific removal rate (SRR), and taper angle (TA). The paper correlates VRR, PR, drilling power, and Young’s modulus of the tested materials. In the case of slotting, VRR, kerf taper angle (TA), and the average surface roughness, Ra, were measured and used as indices of machinability. Cost analysis was also performed to introduce an economical index of machinability for both AWJ drilling and slotting AWJM operations.

Abstract: Resistance spot welding (RSW) is a commonly used process in a variety of fields such as automotive, aerospace, household, furniture, and railway for welding sheet metal parts. These industries further demand a welding machine that is portable and versatile in terms of where it can be utilized, such as, among others, remote locations, and is cost and energy-efficient, reliable, and highly efficient performance-wise. With this aim, the work develops a portable spot-welding machine with specific specifications, of an electrode of 0.394 inches in diameter and 10 inches in length, made of copper, and transformer specifications of 6 V-1500 A with 7 variable current settings. This machine is designed to provide accurate, consistent, and reliable welding readings. Additionally, the machine works on an AC supply of 220 volts, making it easily usable. The machine is found to be cost-effective, with a development cost of only 6100 rupees. It has also been found to be reliable and effective in welding up to two 3 mm mild steel plates under different currents, resistivity, and voltage settings. The machine is simple to operate and user-friendly and with a compact and lightweight design, it is highly versatile and easy to operate for a wide range of welding applications.

Abstract: Researchers have become interested in functionally graded concrete (FGC) in recent years due to its potential to enhance the desired performance. Functional gradation can be carried out in a continuous or stepped/layered manner. Most studies have been conducted on two layered FGC beams by substituting the richer mixes in either tension or compression zone. Previous studies have incorporated and presented the structural design approach of such two-layered beams. Moreover, the layer in the compression zone was assumed to bear entire compressive stresses. Previous studies exhibited savings in cement by up to 37% using a layer of the concrete class defined by exposure conditions around reinforcement and the concrete of minimal structural class. However, using structural concrete of minimal class in the remaining segments may result in a higher reinforcement requirement, reducing the benefits of savings in embodied CO₂ offered by reduced cement consumption. This paper examines how designing the beam as a Functionally Graded Reinforced Concrete (FGRC) beam following Indian Standard 456:2016 affects the cost and embodied CO₂ based on cement and steel consumption through the durability approach of design, wherein the substitution of the layer is considered in the tension zone. The study revealed that a 10% and 16% reduction in cost and embodied CO₂ could be accomplished.

Abstract: Earth-retaining walls (ERWs) are widely used structures in civil engineering, a field known for their substantial environmental impact. However, the current practice of selecting ERW types for a project often neglects environmental concerns. To address this issue, this study proposes a novel process to enhance the rationality of ERW selection. It involves assessing the performance of commonly used ERW types in terms of both environmental issues and economic considerations. The proposed process relies on calculating a total cost (TC), which incorporates the costs of two crucial environmental indicators: carbon dioxide (CO₂) emissions and cumulative energy demand (CED), evaluated using life cycle assessment (LCA), in addition to considering the traditional construction cost of the ERW. By determining the TC for various retaining wall options, engineers can identify the optimal ERW type for a specific project. To validate the effectiveness of this environmental-economic approach, a case study was conducted comparing two ERW types: the conventional concrete-reinforced retaining wall (CRRW) and the geosynthetic-reinforced retaining wall (GRRW). The study evaluated structures constructed at four different heights, ranging from 3 m to 6 m. The results demonstrate that the GRRW is the optimal option, offering a lower TC than the equivalent wall conventionally built with reinforced concrete across all evaluated heights. However, the difference in TC between the two ERWs is more pronounced for taller walls. At a height of 3 m, the total cost ratio between the CRRW and the GRRW is moderate at 1.2, while it substantially increases to 2.5 at a height of 6 m. In conclusion, the proposed process was effectively applied to the case study, providing valuable insights into the assessment of earth-retaining structures from both environmental and economic perspectives. It can assist engineers in prioritizing and selecting the most sustainable and cost-effective ERW type for a specific project.

Abstract: Many populations of isolated and rural areas around the world are facing major problems of water deficit in domestic needs, irrigation and grazing and remains the daily concern of the inhabitants and which are particularly accentuated in the arid and desert areas. In this context, several researchers have recently oriented their research to the solar system. This energy is clean and nonpolluting and its use provides an inexhaustible source of energy. Photovoltaic pumping is one of the applications of solar energy in remote sites where conventional electricity is absent, such as the Algerian Sahara, which has one of the highest solar deposits in the world which can exceed yearly 2263 kWh/m2. This solution represents the ideal technical method for supplying water from wells of groundwater. The main purpose of this work is to evaluate the reliability of solar pumping systems compared to a conventional power system applied to two experimental wells installed in an isolated pastoral region in the Algerian Sahara and precisely in the Ouargla region.The results showed that the generator pumping technique appears to be the least expensive at the beginning of the operation. The balance becomes clearly in favor of the solar pumping solution after a few years of operation (about 5 years), with a 50% benefit in the cost per cubic meter of water.

Abstract: The basic function of building cladding is to protect the interior against the effects of the external environment. To fulfil this function, cladding must have good thermal and technical properties. The development of construction industry in the then Czechoslovakia after World War II led to higher demands on the construction of administrative and civil buildings in terms of capacity and speed of construction. To achieve these aspects, the construction industry was industrialised. The execution of building cladding with light prefabricated structures allowed to pre-define the required product quality and guarantee its sustainability for the time. On the other hand, due to technological indiscipline, low durability of used materials, poor sophistication of construction details and thermal and technical parameters of the structure, there were many problems which resulted in gradual degradation of these structures and increased necessity of their revitalisation. There are many ways to revitalise these structures on the Czech construction market. In general, contemporary revitalisation systems can be divided into three basic groups. These groups represent the individual stages of revitalisation. The first stage of revitalisation is simply the replacement of window panes. Another (second) stage is the replacement of window panes together with the modification of the panel part of the original structure. The last (third) stage is a complete replacement of the existing cladding with a new one. To evaluate the effectiveness of revitalisation, it was necessary to create a simulated building to which the design variants of these revitalisations were applied. It is clear from the simulation results that the best result is achieved in the second stage of revitalisation, where the window panes are replaced and the panel part of the original cladding is modified. This achieves the optimum ratio of expended financial costs for revitalisation and improvement of the thermal and technical properties of the structure.

Abstract: Construction project costs are often related to the availability of construction materials and proximity to the work site. So this paper studied the effect of transportation of materials on the cost of construction projects in the desert and identified the increment percentages of materials cost in comparison with main cities and re-accounted the BOQ items prices in the desert cities. The results showed that the cost of some works may be doubled in the desert areas due to lack of construction materials and high transport costs.

Abstract: This paper analyzes the issue of assessing the efficiency and possibility to use helicopters when designing and implementing the projects of reconstructing single-storey industrial buildings by replacing the structure of their roof. It demonstrates the expediency and possibility to use helicopters for these purposes as well as the way of finding rational areas of use thereof in connection with determining factors of external and internal constraints of the facility, as well as its technical state. In this paper we formulate the tasks and present the obtained research results that increase the efficiency of organizational and technological solutions in reconstruction projects of specific single-storey industrial buildings. Here we also outline the ways of further development of design methodologies in regard of technology and arrangement of reconstruction works based on studies and use of quantitative relationships of time and cost indicators with the selected properties of facilities to be reconstructed.

Abstract: Seismic retrofit of industrial buildings usually consists of traditional strengthening methods such as the addition or replacement of braces and welding of plates. This implies that the seismic force is maintained, or in some cases, increased due to stiffening. Consequently, a large amount of steel is needed to satisfy the code requirements. However, the use of buckling restrained braces (BRBs) as an alternative to the traditional retrofit increases the dissipation of energy and, as a result, a reduction of the seismic force is expected. This may produce in some cases a reduction of the steel required to obtain an appropriate performance of the building. In addition, the use of BRBs concentrates the dissipation in specific locations, then the behavior of the building is more predictable. In this research, an actual traditionally retrofitted industrial building is analyzed, and a quantification of the benefits of using BRBs instead of traditional methods is made. The comparison between both solutions is based on costs and seismic performance.