Search results

The bid/no-bid decision is critical to the success of construction contractors. The factors affecting the bid/no-bid decision are either qualitative or quantitative. Previous studies on modeling the bidding decision have not extensively focused on distinguishing qualitative and quantitative factors. Thus, the purpose of this paper is to improve the bidding decision in construction projects by developing tools that consider both qualitative and quantitative factors affecting the bidding decision.

This study proposes a mixed qualitative-quantitative approach to deal with both qualitative and quantitative factors. The mixed qualitative-quantitative approach is developed by combining a rule-based expert system and fuzzy-based expert system. The rule-based expert system is used to evaluate the project based on qualitative factors and the fuzzy expert system is used to evaluate the project based on the quantitative factors in order to reach the comprehensive bid/no-bid decision.

Three real bidding projects are used to investigate the applicability and functionality of the proposed mixed approach and are tested with experts of a construction company in Alberta, Canada. The results demonstrate that the mixed approach provides a more reliable, accurate and practical tool that can assist decision-makers involved in the bid/no-bid decision.

This study contributes theoretically to the body of knowledge by (1) proposing a novel approach capable of modeling all types of factors (either qualitative or quantitative) affecting the bidding decision, and (2) providing means to acquire, store and reuse expert knowledge. Practical contribution of this paper is to provide decision-makers with a comprehensive model that mimics the decision-making process and stores experts' knowledge in the form of rules. Therefore, the model reduces the administrative burden on the decision-makers, saves time and effort and reduces bias and human errors during the bidding process.

Decisions by construction contractors to bid (or not to bid) require the thorough assessment and evaluation of factors relevant to the decision, as well as the quantification of their combined impact, to produce successful bid/no-bid decisions. The purpose of this study is to present a fuzzy fault tree model to assist construction contractors to more efficiently bid for future projects.

The proposed model consist of two stages: first, identification of the factors that affect bidding decision using a questionnaire survey after an extensive literature review, and second, usage of the identified factors to build a fuzzy fault tree model to simulate the bidding decision.

A list of 15 factors that affect bid/no-bid decisions was identified. Analysis of factors revealed that the highest-ranking factors were related to financial aspects of the project. A case study is presented to demonstrate the capabilities of the model, and a fuzzy important analysis is performed on the basic events to demonstrate the differences between three contractors’ bid/no-bid decisions. The results reveal that there is variation between the decisions of each contractor based on their willingness to participate. Besides, the influence of evaluation factors on the final decision for each contractor is different.

The study contributes to the body of knowledge on tendering and bidding practices. The proposed model incorporated the fuzzy set theory, which suits human subjectivity. The proposed methodology overcomes the limitations of previous models as it can, using the linear pool opinion principle, combine and weigh the evaluations of multiple experts. In addition, the model is convenient for situations where historical data are not available.

This study aims to theoretically investigate the effect of activating corporate governance (CG) mechanisms on the association between adopting corporate social responsibility (CSR) and tax avoidance (TA). Based on the analyzing of the previous studies, the authors support the results of studies that found a positive effect for activating CG on the adoption of CSR. Also, they found that there is a negative impact of activating CG mechanisms on TA, as CG includes controls and procedures that contribute to limiting opportunistic behaviors of management and ensures making decisions that maximize value for shareholders. To the best of the authors' knowledge, it is the only chapter that examines the effect of activating CG mechanisms on the association between CSR and TA.

This paper aims to study the static characteristics of the hydrostatic conical journal bearings by utilizing single-action membrane restrictors to compensate the working pressures of recesses.

The flow resistance network method is used to analyze the influences of load capacity and static stiffness of bearing with the design parameters, including the number of recesses, radial eccentricity ratio, axial displacement ratio, restriction constant, membrane compliance, length-diameter ratio, circumferential land width ratio, axial land width ratio and half of cone angle.

This study shows the infinite stiffness of the oil produced in the first and second recesses while single-action membrane restriction constant of 2 and 3, respectively, as well as in the fourth recess while single-action membrane restriction constant of 0.01 and 0.1, respectively.

This article provides the hydrostatic conical bearings in static and unbiased states for analyses of design parameters. The analyses ignore dynamic pressure effect and do not use the Reynolds equation, and assuming that each oil recesses pressure is constant.

The influences of the design parameters including the number of recesses, membrane restriction, membrane compliance, length-diameter ratio, half of con-angle, circumferential land width ratio, and axial land width ratio are discussed to the load capacity and static stiffness of conical bearing.

Based on the characteristics of the conical bearing through analysis, this article suggests the front bearing with hard membrane restrictor (capillary) and the back bearing with soft membrane restrictor are the most appropriate for axial stiffness.

Formwork design and construction for reinforced concrete buildings take significant time, effort and money. Construction procedures are time-consuming for designers and costly for the contractor. Poor engineering decisions have led to several workplace accidents in the construction industry. This paper aims to present an integrated building information modeling – genetic algorithm (BIM-GA) model to automate formwork design, 3D visualization and optimization.

Data are precisely extracted from a 3D structural model and used to optimize formwork design based on available formwork components and prices. Optimization models are made using GA approach. A library of 3D formwork components was modeled and stored using Revit. The optimized design solution thereafter would be visualized automatically in Revit to readily acquire formwork quantities schedules and shop drawings.

A case study illustrating the proposed approach demonstrated that using BIM will reduce formwork design, quantification and drawing time by more than 50% of the traditional approach with safer design and accurate results due to process automation and optimize cost for the given data.

This research introduces an innovative integrated BIM and GA model for the optimization and automation of slab formwork design, which has significantly benefited the construction industry. The utilization of GA in the optimization process allows for the attainment of an optimal formwork design, ultimately leading to a reduction in construction cost and time.

This study aims to investigate the use of CdO nanoparticles with recycled aggregates (RAs) and its effect on the structural behavior of reinforced concrete (RC) slab elements.

The study has been conducted through three phases: in the first phase, the structure of lab-synthesized CdO nanoparticles was investigated and then cement was partially replaced by CdO nanoparticles to estimate the optimum dose. The second phase focused on the properties of the RA collected from demolition wastes. In the third phase, RC slabs with different concrete mixes using RA and CdO nanoparticles were experimentally tested.

The results indicated good effect of using CdO nanoparticles with RA to improve the RC slab specimens’ behavior compared with the control specimen.

In present times, nanoparticles have a promising importance in the construction field. The influence of nanoparticles on the compressive strength of the concrete has been investigated by many researchers, but using it with RA is considered a new topic.

The construction sector is a major contributor to the Egyptian economy and gross domestic products, plus considered as one of its fastest-growing sectors. Various deficiencies such as low productivity, delays, cost overrun, poor quality, etc. have plagued the construction sector, leading to undesirable project performance across Egypt and several other countries. One of the best methods to measure and improve performance evaluation and consequently a step toward industry improvement is key performance indicators (KPIs). The paper aims to discuss this issue.

A questionnaire survey was conducted to identify the importance index for 35 KPIs. The KPIs were identified and selected based on an extensive literature review and one on one interview with expert construction professionals. Moreover, exploratory factor analysis method has been used to analyze and determine the inter-relationships between the set of indicators.

Seven indicators that have the highest importance indicator were selected to create project overall performance indicator assessment models to consistently measure the performance of different construction projects. Seven equations are introduced reflecting the output of the research while considering both organization size and project type.

The proposed evaluation assessment models can be used to: evaluate the relative success of projects; indicate the areas of strengths and weaknesses in performance and establish company benchmarking. Three projects were selected to validate the performance evaluation models.

This paper provides mathematical assessment models for evaluating overall construction project performance in Egypt, taking into consideration organization size and project type. Previously published research works on the subject matter are quite limited, and frequently deal with only one or two selected aspects.

The present work aims to prepare biocomposites blend based on linear low density polyethylene/ starch without using harmful chemicals to improve the adhesion between two phases. Also, the efficiency of essential oils as green plasticizers and natural antimicrobial agents were evaluated.

Barrier properties and biodegradation behavior of linear low density polyethylene/starch (LLDPE/starch) blends plasticized with different essential oils including moringa oleifera and castor oils wereassessed as a comparison with traditional plasticizer such as glycerol. Biodegradation behavior forLLDPE/starch blends was monitored by soil burial test. The composted samples were recovered then washed followed by drying, and weighting samples after 30, 60, and 90 days to assess the change in weight loss. Also, mechanical properties including retention values of tensile strength and elongation at break were measured before and after composting. Furthermore, scanning electron microscope (SEM) was used to evaluate the change in the morphology of the polymeric blends. In addition to, the antimicrobial activity of plasticized LLDPE/starch blends films was evaluated using a standard plate counting technique.

The results illustrate that the water vapor transition rate increases from 2.5 g m⁻² 24 h⁻¹ for LLDPE/5starch to 4.21 g m⁻² 24 h⁻¹ and 4.43 g m⁻² 24 h⁻¹ for castor and moringa oleifera respectively. Also, the retained tensile strength values of all blends decrease gradually with increasing composting period. Unplasticized LLDPE/5starch showed highest tensile strength retention of 91.6% compared to the other blends that were 89.61, 88.49 and 86.91 for the plasticized LLDPE/5starch with glycerol, castor and M. oleifera oils respectively. As well as, the presence of essential oils in LLDPE/ starch blends increase the inhibition growth of escherichia coli, candida albicans and staphylococcus aureus.

The objective of this work is to develop cost-effective and environmentally-friendly methods for preparing biodegradable polymers suitable for packaging applications.

The construction industry is facing massive challenges due to the huge construction development, and stakeholder management (SM) practices, especially on megaprojects. The purpose of this paper is to investigate critical success factors (CSFs) encountered by key construction stakeholders to enhance SM practices on mega construction projects (MCPs).

A questionnaire survey is carried out among the most important construction companies in Qatar. Three steps are used to finalize and evaluate the questionnaire before proceeding with the full survey, validity, pretesting and pilot study. Quantitative data analysis was conducted using the Statistical Package for Social Science software.

This paper identifies the key factors contributing to improving SM performance in MCPs; none of these is uncommon, but here they come together in a more integrative way.

The limitations related to this research are briefly outlined as follows: the research was carried out in the State of Qatar. So, the findings are limited to the Qatari construction industry. The construction industry in Qatar is different from other countries where public projects have the priority to develop the infrastructure of the country prior to the world cup competition. The scope of this research is limited to MCPs. The impact of low awareness and knowledge of SM is not considered. However, the study is still reasonable and fortunately suitable to evaluate SM in MCPs.

Identifying these factors is expected to assist project participants in MCPs in improving projects’ performance and completing construction within the predefined time and cost.

This study makes a significant contribution through identifying the CSFs that lead to develop efficient SM in MCPs. Moreover, the research findings are important for project stakeholders, organizations, contractors, engineers and local authorities who implement SM in MCPs. Moreover, it will enhance the application of SM practices in construction megaprojects and allow project key stakeholders to place emphasis on tackling the crucial challenges identified in this research.

Rapid urbanization and the shortcomings of traditional construction methods motivate construction professionals to explore faster and more sustainable approaches such as off-site construction (OSC). Thus, the purpose of this paper is to identify the drivers influencing OSC adoption and to explore the key drivers of its widespread adoption in Egypt.

A comprehensive global literature review was performed initially to develop an up-to-date list of OSC adoption drivers, which was confirmed in the Egyptian context through a pilot study. Then, social network analysis (SNA) was utilized to determine the most influential drivers as well as shortlist them to construct the final questionnaire survey. A total of 57 stakeholders in the Egyptian construction industry responded. Lastly, the relative importance index (RII) was calculated to rank the drivers, revealing the key drivers.

The results revealed that higher productivity, improving project quality control, shortening construction time, improving product quality and improving supervision and inspection are the top five drivers. On the contrary, government policies and regulations is the least significant driver.

This research contributes to the body of knowledge by introducing a comprehensive, up-to-date list of drivers, which helps the stakeholders gain a better understanding of the driving enablers of adopting OSC generally and helps Egyptian stakeholders make more informed decisions about its implementation specifically.