No abstract

Project delivery quality (PDQ) is a potential target of the construction team, which is working on enhancing this quality thru project stages: design and construction. A very important side of this work is study and research to investigate the critical factors affecting PDQ. Some former studies uncovered that the delivery methods: Design-Build (DB) and Design-Bid-Build (DBB) notably affecting PDQ. A study appraised the mentioned methods among several features, such as: time, communication, drawings …etc. This paper assumes that there are other critical features to be studied as it's believed to complete the appraisal among DB and DBB. The aim of this paper is to get sound results for deciding which of them will contribute in enhancing PDQ. The paper will run unstructured conversations with design and construction players: owners, consultants (design/supervision), and contractors. They were requested to provide their feedbacks regarding (6) chosen features among DB & DBB. Also, they were asked to justify their scores adding more details. Collected data was organized, tabulated, and analyzed, then discussed, and concluded.Being DB in nature, the involvement of the consultants was easier, as they were contracted to the main contractor (the direct participant in the project), and the contractor also has a closer and earlier involvement of the main contractor in the design process with more consideration of build-ability issues [1].DB is not a new method of project delivery; its roots go back to antiquity. P Thomas mentioned that the pyramids were built though DB, as well as Saint Paul's Cathedral in London, but it fell into disuse in the United States about the time of the Civil War, and gave way to the "new" design-bid-build process through the latter years of the 20th century [2]. Also, he said that the DB delivery of buildings makes it less expensive and more certain that owners will get high performance and sustainability from their new buildings and renovation projects.Although the importance of DB operational differences is widely accepted, there is as yet little agreement of their classification. Different rules and terminologies are used and some of the classifications are contradictory [3]. For example, Janssens D.E.L (1991) and Akintoye A. (1994) consider Design and Manage to be a DB variant [4, 5], while Masterman, J.W.E. (1992), in contrast, refer to Design and Manage as a management-oriented procurement system [6]. Quatman G.W. (2001) and Gransberg D.D et al. (2006) include Bridging as a DB variant [7, 8]. In Beard et al. (2001) classification framework however, Bridging is not regarded as DB, because it is more akin to traditional Design Bid Build and the client/owner is again in the position of warranting the completeness of the design to the bridging contractor [9].Also, it's worth mentioning that The Direct DB process is qualifications-based, which involves the selection of a contractor through negotiation, and the selection of the team is primarily based on qualitative criteria such as past performa...

Recycled concrete aggregate (RCA) collected from the demolition of old reinforced concrete structures can be reused to prepare structural and non-structural concrete, thereby protecting the environment by preserving natural resources. This study explores RCA’s use, collected from the crushed concrete of different building projects in Riyadh, to manufacture fresh self-compacting concrete (SCC) and investigate its properties in the fresh and hardened state. Four SCC mixes were prepared by replacing natural aggregate (NA) with RCA at 0%, 25%, 50%, and 75% replacement levels. The water-cement (w/c) ratio was maintained constant at 0.38 for all the mixes. Slump Flow, J-ring, and V-funnel tests were performed on the SCC mixes in the fresh state, and the compressive strength of hardened concrete was determined after seven, 14, and 28 days. Water absorption and split tensile tests were also carried out for all the mixes. The findings revealed that it is possible to reach compressive strengths higher than 40 MPa at 28 days for RCA replacement level of 75% by using a superplasticizer and low w/c ratio. The decrease in compressive strength concerning the SCC-NA mix was 25% for 75% replacement level. The highest split tensile strength at 28 days was around 3.3 MPa for a 50% replacement level. The lowest water absorption was 3.2% for SCC-NA, which was gradually increased and was highest at 5.6% for 75% replacement level.

One of the activities that are almost used by instructors to assess the undergraduate learners (students) performances in the teaching and learning system is performing researches. It's most probably that learners prepare a presentation for the research, through which they conduct their ideas to the audiences (the instructor and their colleagues). Recently, a phenomenon was monitored regarding the research preparation process practiced by the learners, that the majority go directly to the websites, in which they could easily find tons of attractive and ready-made information that fill the gaps of their heavy homework gained from several courses. It's a convenient activity for learners to go through this easy path to fulfil their duties, but the issue is that the output of such path is so weak. The gained information in this case is so shallow, loose, and could easily been evaporated after a while. There is a need to examine the impact of a missing skill in the current learners' generation: the reading practice. It's noticed that library visits to read books were strongly decreased compared with what was happening in the older generations, where the piece of information was hard to collect, but in the same time, is hard to be forgotten. As a part of the teaching and learning process, and through a college of Engineering, this study will introduce results of the comparison between the outputs of the two methods of collecting information: through the web, and through the traditional book reading. This is to highlight the importance of reading through an experiment applied on one section of students who were asked to prepare a research from a certain chapter of their textbook, and compare that with a prior research they had prepared from the websites. The results were impressive and reflected the importance of the missed reading activity.

As the world is giving climate change a higher priority, several Coalitions are working on meeting a clean and green environment (SDG 13), focusing on new streets’ design in total urban development. A previous study discussed the pedestrian mobility status in Riyadh city, with attention to sustainable mobility, considering the pedestrians’ traveling patterns that use their cars rather than public transportation. This paper investigates the Ecomobility that seeks to promote the integration of passenging, cycling, wheeling, and walking. This approach will provide better health (SDG 3), clean air, mobility and accessibility, noise avoidance, greenhouse gas emission reduction, individual cost savings, and energy efficiency (SDG 11). It analyzes the pedestrians’ traveling modes in Riyadh city through a case study of the Prince Sultan University’s (PSU) community, then evaluates the pedestrians’ environment quality in the campus surroundings. Analysis used a web-based survey referred to the PSU people, including Students, Faculty, and Staff. On the other hand, the pedestrian’s environment quality was evaluated on-site built on well-constructed criteria. The assessment’s results addressed the factors influencing pedestrian choices and underlined the barriers to transformation to Ecomobility. They revealed that around 73% of the respondents expressed willingness to transform to ecomobility modes. About 52% of the survey sample preferred the public bus option. For the non-motorized options, students preferred cycling and wheeling modes, while faculty members and staff preferred walking. Based on conclusions, recommendations are proposed to foster pedestrian ecomobility for sustainable urban development in Riyadh city.