ABSTRACT. Umm Lekhba (Landmark) Interchange is the largest four level interchange being built in Doha-Qatar, which have 9 number of Flyover Bridges with 11 km in total length, constructed partly using 735 number of heavy precast concrete segments fabricated off-site, transported, and installed using heavy cranes and Launching Trusses with a minimum impact on the Public Traffic flow and on the shopping activities at the busiest interchange in Doha. The Lean Construction Institution of Qatar (LCI-Qatar) was established in October 2019, and  the Lean Construction implementation became a mandatory for all Ashghal’s new Projects in Qatar as of 2022, however the construction of Landmark Interchange was started in May 2017, and two of its Flyover Bridges were opened to Traffic at the end of 2019. The Contract of the Landmark project dose not mandate implementation of Lean construction but the Contractor had implemented part of Lean Construction and BIM techniques at his own cost to overcome the challenges faced in the Design and Construction of the Project, including consideration of using the Last Planner System, Organization/Standardization of the workplace ,implementation of Just in Time concept, using a systematic Procurement approach ,Utilization of multi-layer Subcontractors and Consultants, etc. This paper will present briefly the Construction of Landmark Bridges and discuss the Lean implementation during the Construction.

ABSTRACT. This paper highlights the realized benefits of adopting and implementing a tailored lean construction strategy along with its dynamic action plans during the Construction phase of one of the recently completed infrastructure projects in the State of Qatar. The study includes using various enhancement measures and criteria combined with best practices by different project teams from all involved parties. The paper also proves the influence of producing a systematic work process during the project life cycle on overcoming challenges and barriers, in which the critical elements of accomplishment, improvements, and the conditions of satisfaction are adequately outlined and recorded. Through this paper, the lead author claims to achieve one primary goal, which is to name the most crucial barriers found to affect the deployment of the lean construction concept within the construction industry based on data collected from four infrastructure projects, including the evaluated one in this paper. The required data was collected and collated through questionnaire surveys conducted on 57 professionals following many interactive workshops held by the lead author about the importance of lean construction implementation in construction projects. Concurrently, data analysis outcomes were used in the PDCA cycle of continuous improvement. The findings emphasize the importance of leadership engagement in lean deployment processes, and training sessions/ workshops, besides rewarding the project team members as a pillar towards an ideal productivity level with the practical usage of resources in addition to the delivery of the utmost value to the Client.

ABSTRACT. The improvement of efficiency, quality and profitability has always been the major goal for the architecture, engineering, construction and operation (AECO) industry. The last planner system (LPS) as one of the main important methods of lean implementation can be implemented in design projects as well as in construction projects. This research is divided into three parts; first part is about Lean concept definition, values and wastes, challenges faced, and lean implementation. Second part is focusing on the last planner system, its definition and method of implementation. Third part is a case study of how LPS is implemented in managing a design project in a design consultancy firm, how to lead the lean enterprise, and how to deal with change resistance within the team.

ABSTRACT. An organization leadership culture is the corner stone of success or failure. This paper focuses on Lean Leadership as an emergent concept introduced to many organizations where leaders are role models, empower their teams and make them accountable. In construction projects, culture is usually the combination of behaviours, attitudes, and communication inherited from previous experiences. A culture change is not welcomed unless mandated by the leadership and practiced daily. Where many factors are similar, two projects had different outcomes. A root cause analysis, on two infrastructure projects with the Public Works Authority ASHGHAL in the State of Qatar, reveals that project culture is the driving factor on a successful delivery on time and budget, and complying to quality, health and safety, and environment standards, with a public satisfaction focus. Client pre-set strategic objectives are achieved through a collaborative effort of project team where accountability is the bonding agent between promises and accomplishments. This paper summarizes a lean leadership culture adoption where it established a psychological safe working environment that delivers project to client expectations.

ABSTRACT. Current research on sustainable construction has primarily concentrated on the design and operation phases of projects. However, the enhancement of execution and production phases of infrastructure construction projects have received little attention. In this paper, value stream mapping (VSM) is used, as a lean production tool, to evaluate production operational waste during the project construction phase. VSM considers the development of process maps that support project managers in diagnosing the current state of production in order to propose future improvements. VSM addresses the underlying causes of issues, as opposed to the symptoms addressed by traditional tools. This paper presents a case study of the application of VSM in the construction of infrastructure projects to improve the manhole and high-density polyethylene pipe connection process. This study's primary contribution is to provide a comprehensive account of the application of VSM in the infrastructure construction industry, confirming its ability to identify the sources of production waste, quantify them, suggest reduction strategies, and develop a TAKT planning. The case study’s result demonstrates an effective approach to enhance the performance of construction projects targeting to optimize the resources use and reduce costs, improve quality standards, mitigate the associated wastes and enhance the TAKT time concept in construction of deep utilities in infrastructure construction project.

ABSTRACT. Decision making is part of the daily duties of researchers, engineers, and consultants, and taking the right decisions requires quantitative assessment which usually needs data and analysis. In construction industry, data collection or detailed analysis are practically complicated that cannot drive the right results. This fact leads to the common use of qualitative assessment where the numbers are not available, and the evaluation is involving various criteria from diverse perspectives. As a lean tool, Choosing By Advantage (CBA) is used predominately in Design process. This paper presents the CBA practice as a qualitative assessment tool in construction phases in the Lean Construction implementation in infrastructure projects. The flexibility of CBA as a multicriteria decision-analysis (MCDA) model helped overcome the differences between criteria, categories, and value-based analysis. This paper describes the experience of selecting option that consider advantages from various criteria in an extensive assessment.

ABSTRACT. This paper examines the short-term deflection of reinforced concrete slabs taking the tension-stiffening phenomenon into account. The main goal of this study is to develop a model that predicts the deflection of one-way slabs made of reinforced concrete. The model takes into account concrete contribution in carrying tension between cracks thoroughly considering the stress-strain relationship material model. The model has been developed using MATLAB Program incorporating a numerical technique known as the layered approach. The developed layered approach model was validated using experimental deflection results reported in a previous study. Based on the experimental validation, the model showed its tendency in predicting the real-case deflection of one-way concrete reinforced slabs. It was concluded that different types of tension stiffening models can be added to the program to model deflection and crack propagation.

ABSTRACT. This paper studies the feasibility of producing self-healing concrete by immobilization of bacteria on the sand. In this study, the Gum Arabic (Acacia Senegal) was used to immobilize bacterial spores and its nutrient (Calcium lactate) on sand surface as a novel technique. Due to its availability and environment-friendly, Bacillus subtilis bacteria have been selected and prepared. To achieve the aim of this study, three concrete mixes were made with 10%, 5%, and 2.5% of gum-capsulated sand with bacteria. The ability of Self-healing of cracks was monitored using stereomicroscope and digital image camera. The experiments have shown that the efficiency of the proposed technique in crack healing without impairing the prisms’ strength for mixes with 2.5% and 5% of gum-capsulated sand with bacteria. The results give a proof-of-concept to use Gum Arabic as an adhesion to immoblize the bacteria and its nutrient on sand to produce self-healing concrete.

ABSTRACT. Eco-friendly concrete is the most recommended sustainable option to reduce the excessive diminution of concrete natural resources and the high generation of greenhouse gas emissions. Therefore, this study explores the feasibility of utilizing treated wastewater (TWW), recycled concrete aggregates (RCA), and fly ash (FA) in reinforced concrete (RC) beams. A total of four RC beams with dimensions of 180×250×2000 mm were constructed and tested to failure under a four-point flexural bending setup. The test parameters were the type of mixing water (fresh water and TWW), coarse aggregates (natural aggregates and RCA), and cementitious binders (cement and FA). The experimental results revealed that the beams’ ductility was reduced by 9% and 16% with TWW and RCA, respectively. Moreover, the flexural capacity of the TWW concrete beam was decreased by 14%, whereas RCA-RC beams showed comparable flexural strength to its counterpart with natural aggregates. In addition, the utilization of FA at a 20% replacement ratio enhanced the flexural strength by 5% to 7%.

ABSTRACT. Nowadays the global trends in construction industry is to reduce the cost, saving energy and preserving the environment. Using other industries waste material as a construction material is one of several methods followed to meet these trends. Management of solid waste considered as one of the most significant environmental issues not only in Oman, but globally as well. Around 1.7 million tons of solid waste yearly generated in Oman. More than 120 million tons of constriction’s demolition waste yearly generated over the world. Besides, 10 - 30 % of Oman solid wastes produced from construction field (concrete wastes and aggregate) and just dumped in the landfill area without any further use. In this paper, the influence of replacing the demolition waste with coarse aggregate on the mechanical properties of concrete was studied in terms of compressive, flexural, and tensile strengths, and workability. The concrete properties were evaluated by replacing of 20, 30 and 40% of coarse aggregates with demolition waste in the mix proportion of C-35 concrete and the experiments results were compared with each other as well as with conventional one based on two different periods of 7 and 28 days. The results were satisfactory so it could be concluded that replacing of up to 40% of coarse aggregates with construction and demolition waste is still safe and not causing dramatic reduction in the concrete strength.

ABSTRACT. The present paper investigates the hardened properties of self-compacting concrete by reusing granite waste to replace natural fin aggregates. The reuse of solid wastes as powder or aggregates allows to produce sustainable concretes that have lower environmental impacts and reduced cost. In this work, granite waste was used as a partial replacement to naturel river sand in self-compacting concrete (SCC). For this purpose, four mixtures were designed in which three contained a combination of river sand (RS) and recycled granite (RG), and one included only river sand (RS) as reference mix. Compressive strength, flexural strength, ultrasonic pulse velocity and water absorption were investigated for the hardened SCC at 28 days of hydration. The results showed that the introduction of RG has no effect on compressive strength of SCC. Adding 30% of RG increased flexural strength and by 12%. According to ultrasonic pulse velocity results, the use of RG resulted in more compactness and homogeneous SCC. In addition, SCC including RG showed less water absorption.

ABSTRACT. The paper investigated the mitigation of cement alkalis and siliceous of aggregates reactivity (ASR) influence in hydropower concrete structures and takes Merowe Dam Project (MDP) and Dam Complex of Upper Atbara Project (DCUAP) as case study. The results of the cement material; OPC and GGBS used in both projects, was of low level alkali content, less than 0.6% of Na2O equivalent The results of crushed and natural aggregates; combined with moderate and high levels of alkali content cement for expansion test, was of low level reactive aggregates. Based on the laboratory testing results obtained from petrographic examination, chemical tests, mortar bar tests and accelerated mortar bar tests concerning alkali silica reaction for fine and coarse aggregates used in concrete and mortar production for projects, all the results fulfilled and verified the standard requirements and limits stated for mitigating alkali content in the cement material and the siliceous found in the aggregates materials, therefore, the concrete and mortar produced from such materials were mitigated from deleterious expansion and damage due to alkali silica reaction. Using of supplementary cementitious material (SCM) Fly Ash to replace 25% of the Cement used in concrete mixes not only for minimizing risk of any probable Alkali-Silica Reactivity mitigation reason, but also for reducing heat of hydration, as a filler to reduce seepage, to increase workability of concrete and as a benefit by reducing the cost of concrete production. It is obvious, from the testing results obtained; to mitigate alkali silica reactivity; there are two options: combine innocuous aggregate with even high level alkali content cement will fulfill the standard requirements for mitigating ASR or combine reactive natural sand with low level alkali content, also will mitigate ASR.

ABSTRACT. Well-designed pedestrian facilities are essential to promote walking among residents. These facilities also act as safe space for use of cycling and other personal mobility vehicles. In 2018, Ministry of Transport developed a system to assess the pedestrian environment, called Pedestrian Environment Review System (PERS). The PERS system is intended to assess, in a consistent systematic way, the quality of the pedestrian environment. This paper applies the guidelines of this manual to assess the walkability in Doha City. A total of ten links and ten crossings were included in this study. On-street evaluation was completed for each selected element and relevant scores for each parameter was assigned. The links assessment demonstrated that, overall, there were some issues highlighted by the PERS Audit in the studied areas such as poor curb ramp design, placement of obstruction on the pavement, lack of tactile information, conflict between pedestrian and vehicles at side-entry intersections, unavailability of wayfinding materials, etc. The overall pedestrian environment in the wider area assessed was generally positive, adequately maintained and of an appropriate quality. The provision of poor-quality crossings was identified as a negative feature of the studied areas. The issues were related to the infrastructure itself. Recommendations are made based on findings to improve the walkability of pedestrian network in State of Qatar.

ABSTRACT. Safe egress plans are critical for crowd evacuation at touristic attractions, particularly during special events, as visitors are often unaware of their options. Identification of bottlenecks in the walking spaces is vital for the development of safe and efficient crowd management and evacuation plans. This paper aims to explore crowd management and evacuation strategies for pedestrian egress flow in Souq Waqif, which is a famous touristic attraction in Doha, under varying crowd demand conditions. PTV Viswalk pedestrian simulation tool was used to evaluate crowd evacuation strategies and identify potential bottlenecks during the egress of crowds. Several guided and unguided evacuation scenarios were developed to understand the egress patterns to the allocated assembly areas inside the Souq. Crowd demands and densities were estimated using publicly available data. Eight major locations were identified as the bottleneck during the simulation. Simulation outcomes highlighted that the current evacuation plans and assembly locations are inadequate in providing safe evacuation routes. However, guided scenarios reduced evacuation times considerably when compared to unguided scenarios, particularly when the demand is high. A sensitivity analysis was also conducted to identify the effect of variations in walking behavior parameters in the simulation model. Variations in the walking behavior parameters changed the evacuation times considerably. Thus, proper calibration of walking behavior parameters considering local conditions could improve simulation accuracy. This study helps to identify probable bottlenecks and their characteristics that could help policymakers to assess the effectiveness of evacuation plans and crowd management strategies for crowd safety.

ABSTRACT. Walkability is a crucial in sustainable urban design. Our understanding on the walkability in cities in hot and arid climate needs to be improved due to shortage of our knowledge and previous studies about this. Thus, this study aimed to demonstrate the value of sustainable urban design in enhancing downtown Abu Dhabi residents’ walking experience. Urban neighborhoods’ quality of walking environment and the scale of the downtown’s super block in Abu Dhabi Main Island and were measured. In addition, it is examined how its urban design influences walking behavior by selecting two study sites based on land use diversity. To measure them, the current study investi-gated the (1) walkable distance in Abu Dhabi; (2) scale of pedestrian movement; and (3) potential purpose of walking patterns of pedestrians of urban infrastructure. Site observation and surveys were carried out for collecting data that supports people’s perceptions linked to walking purpose, quality, frequency, and intensity. To analyze these data, the geographic information system was employed. With this study, walking distance for the utilitarian purpose service in Abu Dhabi block cover by 0.5 miles. There is the active movement regardless of the extreme weather condi-tions both weekday and weekend. This study data could potentially guide designers and policy-makers to create a healthier walking environment for Abu Dhabi residents as well as some cities in hot and arid climate.

ABSTRACT. Globalisation and our fast-paced world have opened up new horizons all over the world. Population growth, rising energy prices and their declining nature are creating problems for transport. Road congestion, drastic increases in journey times and rising travel costs have highlighted the importance of improving public transport. However, for public transport to be attractive, it is essential that the transport alternative itself is fast, comfortable and modern. In this paper, we examine two metro construction projects in cities with high populations from a project management perspective, with a particular focus on the main purpose of the project, its usability. In this study, we want to highlight the visible goals expressed by the end users and their reflection in the project. We want to focus on the different phases of project management that lead to the success of the project.

ABSTRACT. Visual quality assessment has received much attention in research by forest management and landscape researchers after the mid-twentieth century with the advent of legal frameworks enacted to protect natural resources, including scenery. Since then, the field has gained momentum that mostly attached to landscape change and assessing changes' environmental impact. Urbanized areas, however, received less attention and just started to receive some exposure in the last two decades (concurrently with the emergence of new technologies of GIS and remote sensing). Developing a comprehensive understanding of the visual quality assessment research requires a reconnaissance survey of its history and the trends of its research growth. This study undertakes an analysis of visual quality assessment literature in the context of urban settings using bibliometric tools. The paper employs quantitative techniques to analyze 3,221 journal papers retrieved from the Web of Science using keywords co-occurrence, citation burst, and direct citation analyses with the help of VOSViewer, CiteSpace, and Gephi software. Here we show the discipline’s status quo, trends, and patterns of development. They confirm the recency of urban-related research. Our study touches on the chronological emergence and decay of major visual quality notions. It also highlights the most central studies and the journals and research groups actively working in the field. Moreover, it points out research gaps related to urban spaces for future studies guidance.

ABSTRACT. Health and wellbeing have been key considerations in designing sustainable environments. However, most research on built environments and wellbeing has been conducted in Western communities, with very little research in the context of Middle Eastern countries. This study aims to fill the gap by investigating the impact of the residential built environment on social wellbeing in the cultural context of Doha, the capital of Qatar. The research studied six neighbourhoods in Doha. The investigation used subjective and objective methods such as interviews and spatial models (space syntax), complemented by questionnaires and an observation survey. The data were analysed separately; however, they are thematically discussed in this research. The findings of this research broadly support the work of other studies in this area, linking public spaces with the inhabitants' casual interactions. However, this research found that some uses have a higher impact than others. In Doha, mosques significantly influenced inhabitants' social interaction, especially men. The social relationships between neighbours were maintained in private spaces – Majles-. Majles had low integration with other spaces in the dwelling, which ensures household privacy. Based on the findings of this investigation, recommendations are made and guidelines developed for future residential developments in Qatar and the surrounding region to ensure the social wellbeing of communities.

ABSTRACT. The migration of colloids within porous media has a critical impact on many important industrial processes such as oil production and groundwater recharge. Colloids can clog the pore space and hence impair the permeability of fluids which adversely impact the efficiency of fluids movement through such media. Therefore, understanding the mechanisms of pore clogging at the pore-scale is critical to develop efficient remediation methodologies for permeability reduction at different physio-chemical conditions. To study pore clogging at a pore-scale, microfluidic chips were fabricated to mimic geometries of natural porous media extracted from tomographic scans of sand packs. A colloidal suspension was injected in three phases into the system. The phases consisted of an initial imbibition of the suspension, followed by drainage of the suspension from the system, and finally, a second imbibition. During each phase, a series of images are taken of a section of the porous media. Findings reveal that pore-clogging considerably impairs saturation levels of the porous media through blocking the flow from reaching the gas phase within the system. Considerably increasing the time the gas is trapped in the pore-space, which in turn develops higher irreducible water saturation. This was also observed in the case of drainage of the colloidal suspension from the pore-space where colloids blocked pathways of the gas phase and prevented its migration through the pore space. In contrast, the migration of colloids was also impacted by the presence of the gas phase. Gas provided a clogging surface while forcing colloids to migrate through the pore space and accumulate at other pores. This implies that gas phase presence within a low porosity system can increase pore clogging at a significant rate. This is also supported by the period between the clogging of two pores and the clogging of a dozen pores within the observed system.

ABSTRACT. Oil and gas production is accompanied by generation of large amounts of produced water as usually three barrels of produced water is generated for each barrel of oil. Membrane-based water reclamation technologies have been applied to treat produced water. However, the presence of oil content in the produced water makes its separation very complicated due to the high affinity between oil droplets and the hydrophobic polymeric membrane. This, results in low permeate flux, low oil rejection and high irreversible fouling. In this study, graphene oxide (GO) was functionalized using chitosan (CH) to synthesize GO-CH that was further functionalized with SiO2 to produce GO-CH-SiO2 nanocomposite. Synthesized GO-CH-SiO2 was embedded in the polysulfone membrane matrix to modify the pristine Psf membrane and impart super-oleophobic properties to the membrane. Produced nanocomposites properties were characterized using XRD, FTIR and TEM analyses, while synthesized membranes were characterized for their porosity, pore size, membrane resistance and hydrophilicity. Different ratios of GO:CH were applied with a fixed SiO2 loading to produce modified membranes. Performance test for the membranes modified with 0.3wt % nanocomposite with a GO:CH ratio of (2:1) showed a 271% improvement in membrane flux compared to pristine membrane while a ratio of 1:2 (GO:CH) gave the lowest total fouling.

ABSTRACT. The Public Works Authority (Ashghal) is contributing to the development of Qatar with the construction of first class, sustainable infrastructure with a high degree of public acceptance by utilizing best international practices. Pumping stations and wastewater treatment plants are traditionally constructed at the outskirts of the cities, as they are generally associated with odour nuisance. However, as the cities are expanded, the facilities become part of the urban fabric and their operation becomes an issue of concern for the citizens. To address this public concern, Ashghal has adopted for its sewer infrastructure, pumping stations and treatment plants for their plants including the under construction, Wakrah-Wukair Drainage Tunnel (WWDT), odour emission limits of 0.5ppb of hydrogen sulphide (H2S) and 0.5 ouE/m3 of odour concentration, which are lower than recognisable levels by humans. Moreover, on the way to FIFA World Cup Qatar 2022™, Ashghal decided to install environmentally friendly and sustainable biological treatment units followed by activated carbon filters to ensure a nuisance-free environment at the existing Doha South Sewage Treatment Works (DS-STW) and the new Doha South Terminal Pump Station (TPS) and to extract and treat air from the tunnels of the recently commissioned Doha South Sewer Infrastructure Project (DSSIP). This paper will present methodologies for determining odour levels in existing and new units, the available odour treatment technologies, and the selected treatment schemes for the above projects.

ABSTRACT. An increase in urbanization and uncontrolled development has resulted in a water stress situation, which necessitates the exploration of alternate water sources. Rainwater has proven to be a prominent alternate water source after being efficiently harvested. On-ground implementation of the Rainwater Harvesting System (RWHs) at a community level in urban areas has always been challenging and requires technological advancement. To facilitate the implementation of RWHs, the proposed study provides a comprehensive methodology by integrating the Geographical Information System (GIS) and the Building Information Modeling (BIM) tools. Initially, the hydro-spatial analysis was performed with a GIS tool to obtain an optimized rainstorm collection network and to aid in establishing the geometrical properties of RWHs. Further, an outcome from the analysis was utilized to develop a visualization model using the BIM tool. The proposed methodology is implemented as a case study in the municipality of Jaipur (India). The developed multidimensional BIM contributes to the sustainability of the project in terms of resources, economy, and efficiency over the life cycle. As an outcome, the proposed study provides a comprehensive methodology for effectively utilizing rainwater to cope with the growing water demand and contribute to flood mitigation in urban regions

ABSTRACT. The self-organization of matter has been extensively explored in recent years, and significant advancements have been made in the field of porous ordered films produced by the auto-assembly of different polymer materials, being block of copolymers, blends of homopolymers or amphiphilic polymers. The hierarchical ordering in micro-organized films, known also as Honeycomb (HC) structure, generates a significant increase of specifics characteristics enhancing certain properties of the materials. The preparation of self-assembled porous membrane is done by different approaches. We use hereby the bottom-up microporous structuring method specifically the breath figure (BF) approach to prepare highly-organized membrane from polymer blends. The foremost motives for using the BF are the simplicity of implementation and the adaptability to multiple systems which make it a robust and inexpensive technique for the production of structured surfaces. The honeycomb (HC) structures formed by the BF is a potential candidate for water treatment as a filtration membrane to treat stable oil-water emulsions encountered in the oil and gas industry. The use of homopolymer blends improves the selectivity, permeability and anti-fouling properties comparing to the commercial homopolymer membrane. This presentation will highlight the preparation of self-assembled blends of homopolymers membrane by BF and their performance for cleaning of industrial wastewater and the fouling/re-use potential.

ABSTRACT. Gash River is located in eastern Sudan. The headwater rises south of Asmara in Eritrea, with length of 280 km and slope of approximately 200 cm/km. It has a catchment area of 21,000 km2, which spreads over Ethiopia, Eritrea and Sudan.During the rainy season, the river shows a flashy pattern with high variation in flow and mean annual discharge - 680 million cubic meters.That seasonal flooding has a negative impact on Kassala Town. Therefore, the main investigation objectives are to provide a better understanding for the hydrological process in this catchment, for further studies and to examine the qualification of the software Soil and Water Assessment Tool (SWAT), under the seasonal surface runoff condition.Within this study, SWAT model was generated and applied to the hydrological modelling of Gash catchment. The catchment was delineated by Arc-SWAT using digital elevation model, with resolution 30m×30m, digital land use map with resolution of 300m2, digital soil map with scale of 1000m2, global weather data. Moreover, daily discharge of Kasala station, from Ministry of Water Resources, Irrigation and Electricity , was used for model calibration.For pre-processing, ArcGIS was required for preparing the maps for Arc-SWAT, and the hydrological data were processed. After the model generated successfully, it was calibrated and validated using daily series data.The model shows a good response in simulating the floods in the whole period. It simulated the flood periods during the years of drought,but there is a weakness in determining the values of each flood.

ABSTRACT. Sinkholes are common and reoccurring problems with potential safety risks to road users and authorities. Sinkhole is a void in the ground caused by natural and/or manmade activities, and mainly associated with carbonate rocks and underground water movement. It occurs suddenly and manifests as a hole in the ground, with the potential to cause significant problems of road closure and interruption to road users and construction activities. With the vast infrastructure development over the last two decades and the majority of soil formation of Qatar exposes limestone and dolomites, the number of reported sinkholes has increased dramatically. This paper presents the development and implementation of new guidelines for the evaluation and repair of sinkholes for the Roads Operation and Maintenance Department (ROMD) at the Public Work Authority (Ashghal). It reviews the methodology adopted for the classification of sinkholes, application of Ground Penetrating Radar (GPR) technique for the early detection of subsurface voids and sinkholes before they become major problems. It also covers the approach adopted by ROMD and its Framework Partners for the repair of sinkholes. A case study is presented on the implementation of the new guidelines for the effective evaluation and repair of sinkholes, with performance monitoring in service. Successful implementation of the new guidelines contributes to enhanced management of road network in Qatar by maximizing asset performance and minimizing accident and service disruption.

ABSTRACT. Ashghal has established a robust system of quality control and quality assurance for all projects constructed by Ashghal. Ashghal Departments are supervising a sophisticated system of quality control and quality assurance processes and procedures, implemented by the Consultants, Contractors, and Key Supply Chain Partners of Ashghal projects (e.g., Sub-Contractors, Key Suppliers, Independent Laboratories). This paper illustrates how Ashghal Quality & Safety Department (QSD) monitors and reports the quality performance in Ashghal constructed projects to ensure continuous improvement and adherence to Ashghal quality strategy, policy mission, and targets. QSD is operating as Third Party, reporting directly to Ashghal President, and is monitoring and reporting the compliance of the industry to the quality requirements defined in Qatar Construction Specifications (QCS 2014), Contracts, Professional Services Agreements, ISO 9001:2015 Standard and specific Ashghal requirements. Effective Root cause Analysis carried out by the auditing team has led to value- adding activities. QSD has established specific Key Performance Indicators (KPIs) for the management of non-conformities and corrective actions, to improve the performance and minimize the deviations and failures of compliance. QSD is conducting focused and system audits at the Ashghal projects and the supply chain and is liaising with departments and individual projects as necessary, to agree on Lessons Learned and Actions to improve the quality of Works. These activities include the establishment of consistent criteria of the qualifications and experience of the quality staff of Ashghal departments and Consultants’ teams. QSD is presenting quarterly presentation to the Ashghal President regarding the performance of the Departments (including Contractors’ and Consultants’ performance) and of the Ashghal Project Managers. The established criteria and evaluation related to the quality are dynamic and reviewed/ updated periodically to ensure the improvement of the Quality Performance of Ashghal Projects.

ABSTRACT. As a result of numerous infrastructure projects, which took place in Qatar in the last decade, unprecedented increase in the demand for construction materials has occurred. In addition, the huge program of infrastructure development has led to production of massive quantities of construction wastes. Consequently, Public Works Authority of Qatar (Ashghal) launched an initiative to use recycled materials in projects in line with Qatar National Vision 2030 and Qatar National Development Strategy 2018 – 2022. A roadmap was developed in 2018 considering the available resources and experiences. Recyclable materials, which can be used in Ashghal projects, were identified. Excavation waste, demolition waste, Reclaimed Asphalt Pavement (RAP), Wadi Aggregate, Crumb Rubber and Steel Slag were selected for reuse. Controlled logistic areas to store, manage and process recyclable materials were established. Moreover, guidelines and prequalification procedures were developed for both materials sources and recycled materials producers. Testing programs were carried out on these materials to identify their basic characteristics. Laboratory trials and field trials were carried out at selected projects. Field trials were monitored and assessed following the local construction specifications QCS 2014. Based on lab and field trials, customized specifications were developed for the utilization of the selected recyclable materials in Ashghal projects. These specifications establish the baseline for construction using the selected recycled materials and determine the criteria and methods needed for quality control. Furthermore, Key Performance Indicators (KPIs), were established for Ashghal project departments to monitor their performance in relation to recycling. Ashghal phenomenal performance in utilization of recycled materials in the last three years is presented

ABSTRACT. Natural washed sand is an undeniable material used in infrastructure development and construction projects of all sizes. Due to the depletion of natural sand at the sources in Qatar, there has been the need to develop new alternative materials as a replacement. Alternative materials such as wadi gravel, marine sand and manufacturing sand, including crushed imported limestone, recycled sand and crushed gabbro have been considered and explored. Consequently, a proposal to encourage local washed sand producers to incorporate different proportions of these alternative materials into the various material demands was considered by the Public Works Department, depending on the application in either structural and/or precast members. The paper primarily focuses on providing an overview of some available alternative materials to washed sand that could be utilized without affecting the physical, mechanical, or strength properties of concrete, precast, and the other construction materials that use washed sand, while at the same time providing a long-lasting, durable and economically beneficially alternative material to the national economy.

ABSTRACT. The quantities of accumulated solid waste materials of sewage sludge (SS) and municipal solid waste (MSW) are increasing in Qatar with potential negative impact on the environment. This paper presents an innovative technology for the production of green cement and advanced construction products from SS and MSW. Chemical composition analyses of the solid waste materials indicated the presence of main oxides available in Portland cement, but at lower contents. The three solid waste materials were incinerated and grinded to produce consistent powder materials of similar sizes to Portland cement. The physical and chemical characteristics of the solid waste materials were investigated and compared to that of Portland cement. Paste and mortar mixtures were prepared by replacing 25, 50, and 75% of Portland cement with the different solid waste materials. Solid waste materials were found to influence the fresh properties of concrete, mainly water demand and setting time. Increasing the content of solid waste materials resulted in reduced compressive strength at all tested ages. SS gave the best performance within the solid waste materials investigated. Recommendations are made on the effective use of solid waste materials in various construction applications.

ABSTRACT. Pavement structures are constantly deteriorating due to different distresses, for instance cracks and rutting, that are initiated and expanded. Deterioration models of pavement structures are important components of pavement management systems (PMS). The deterioration of pavement has been extensively modeled using Markov chains. This paper aims at formulating a more efficient deterioration model to predict the condition of pavement sections. It is proposed to accomplish this by developing a Markovian deterioration model coupled with a metaheuristic search optimization method, namely Genetic algorithms (GA). An essential component of the Markov chain model is the transition probability matrix. In the proposed model, a standard percentage prediction method was used to calculate the transition probabilities. This is then calibrated by integrating the GA method with the Markov chain. The model is based on the historical international roughness index (IRI) data retrieved from the Long-term pavement performance (LTPP) database. To test the validity of the method, a real-life case study is used and the performance of the developed model was assessed using both validation and testing data. For predicting pavement conditions, this study concluded that calibrating calculated transition probabilities using metaheuristic optimization results in better performance than developing the transition probabilities using classical methods. The Markovian-GA model developed in the present study can be used to predict the future condition of pavement facilities in order to assist the engineers in planning the optimum maintenance and rehabilitation (M&R) actions.

ABSTRACT. Effective facility management is crucial to overall firm performance and is becoming a core competency for organizations seeking to gain a competitive advantage and attain their goals. Recent research on facility management indicates that ineffective management is a leading cause of budget overruns, maintenance delays, reworks, variations, non-compliance events, unnecessary risk, and dissatisfied customers. In Qatar, there is an expansion of educational facilities to achieve the 2030 Qatar National Vision of having an educated population through a well-developed, accountable, and accessible educational system. This expansion is causing a growing demand for effective campus facility management (CFM) in order to effectively manage and accurately monitor the performance of campus facilities. Through a comprehensive literature review, expert interviews, and online questionnaire responses, this paper aims to develop a Campus Facility Management Performance Framework (CFMPF) that consists of tactical and strategic critical campus facility management success factors categorized into process groups. The proposed framework provides an operational foundation for benchmarking the CMF performance to support the identification of underperforming areas. The CFMPF has been used in real-world facility management firms to benchmark their performance and determine which areas of management need to be improved.

ABSTRACT. Inexperience and lack of awareness of workplace appropriate actions are the common reasons behind accidents and injuries. Researchers and industry practitioners in developed countries identified more than 12 strategies that might lead to preventing worksite injuries. However, these strategies are specific to the developed context. Developing countries still fail to identify safety strategies that might align with their safety policies and procedures. This paper aims to take the first step toward identifying the best safety strategies in the developing context. Thus, the main research question is How can companies start to implement safety strategies with consideration of their context? This study applied a mixed method to meet the objectives of the study. The Delphi method was used to obtain the needed data. The descriptive analysis shows that four important strategies are identified out of the 12 strategies: Upper management support, Safety and health committees, Record keeping and accident analysis, and Job hazard analyses. The findings of this paper can be used by managers to make defendable decisions to start implementing safety strategies in their organizations. Also, they will illuminate the developing countries' safety culture perspective and the implementation processes.

ABSTRACT. Despite the important and vital role that the construction industry plays in the urban and economic development of any country, it affects the environment greatly due to the consumption of many natural resources, energy sources and the resulting pollution and waste. This paper presents the results of a study on the application of sustainability in construction projects in the state of Khartoum. Data were collected to achieve the objectives of research through questionnaire tool, study sample was a group of consulting offices and contracting companies. Results were analyzed by SPSS statistical analysis program and necessary statistical tests were performed. From analysis of data, results shown that there is no significant application of sustainability in construction projects in Khartoum, and that construction projects are in the early stages from the path of implementing sustainability and sustainable construction. Also, there are many obstacles and challenges facing the application of sustainability in construction projects in Khartoum, such as insufficient Government support and policies, inadequate building codes and regulations related to sustainability and lack of training and education. Therefore, an effort must be made to raise awareness of the concept of sustainability and sustainable construction, also responsible authorities should put the laws and regulations related to sustainability and launch the appropriate guidelines for adopting sustainability methods in the construction industry to reduce its impact on the environment

ABSTRACT. Construction Enterprise Resource Planning (CERP) systems started to infiltrate the construction world after ERPs became crucial in modern enterprises. In simple terms, CERP integrate and keep track of the various processes within construction companies. As a minimum, these possesses include management of general contractors, subcontractors, financial work, accounting, payroll, logistics, workflow processes... Data related to different processes are stored within one unique database. Despite this intuitive objective, developing and standardizing CERP systems to fit the needs of all construction companies is not a straightforward course. This research focuses on the development of a framework that integrate the minimum required modules to be included within a CERP, specifically for road and infrastructure construction companies. This objective is achieved based on literature review on CERP despite its shortage, in-depth interviews with construction professionals requiring CERP, and the results of a structured questionnaire filled by CERP users and developers. The developed framework identifies the procurement module linked to the on-site deliveries as the first stone that should be developed and implemented. Then, budgeting and work progress modules must be added. After that, timesheet and equipment follow-up modules need to be implemented. Limitations encountered highlighted the main considerations to be considered in future work such as the cost, the company’s size, development and implementation period, and type of work.

ABSTRACT. Parade of Trade (PoT) is a game used in Lean Construction to demonstrate the impact of variability on a production system and to promote the value of constraint management in an environment of dependent events. Infrastructure projects usually have a sequence of construction works to an extend matching with the PoT model. Different trades and activities distributed over a large-scale area combined with its arising particular issues; creates a challenging efficiency paradox. Therefore, there is a need to adapt a new tool that identifies; pace maker of the production flow, shows the interactions between different construction stages and trades, and explains the impact of trade progress on one another. The PoT idea used to develop new Visual Management (VM) tool, tailored to bridge the gap in the current model of infrastructure construction management traditional tools, supports the effectiveness of resources utilization and optimizes the project as a whole. Starting from maximizing client’s values and passing through selection methodology; this paper records the journey of developing and utilizing sustainable VM tool; tailored for infrastructure construction projects. It supports: decision making regarding resources allocation; adapting construction batch size; assist in determining takt time and takt zones. Furthermore, it opens the way for further studies from lean researchers and practitioners to develop new lean construction tools tailored to serve infrastructure construction projects.

ABSTRACT. During the construction phase the contractor are providing a set of Mockups for the KEY design elements as a usual industry practice, such mockups are exhibited to the client as a comprehensive combination of the approved samples connected and terminated together to provide a partial theme for the whole project. Usually clients transform the mockup function from being a workmanship checking tool into a design tool, where a destructive real-life scale mockup is inevitable to repetitive spaces or key design items, in contrary however, it will be wasteful for unique spaces or items. Changing the design at the project later stages, will result into abortive work, hence the contractor will either proceed according to the project approvals which will result into unsatisfactory deliverables to the client or the contractor will change the design which will result into a cost and time impact. Therefore, the best way to acquaintance such experience is to build digital mockups with the newly available Digital Twin technologies along with CAVE (Computer Aided Virtual Environment) include VR (Virtual Reality) equipment, which can be employed as a robust solution in due times, exhibiting such digital mockup to the stakeholders where they can engage instantaneously without abortive works. The goal of this paper is to formulate and develop a methodology for creating mockups using digital twin technologies during the construction phase.

Its recommended to include such technologies in future tenders, which will not eliminate the use of physical mockups but surely it will be an added value to the Architectural, Engineering, Construction, and Operation (AECO) industry.

ABSTRACT. Building construction and infrastructure development have been a component of major civilizations throughout their history. Great examples of architecture include the Great Pyramid, the Great Wall of China, and many more ancient constructions of historical significance. The fundamental components of these buildings' completion are design, planning, execution, and closer. Planning of project execution is the most critical aspect, to have the ability to accomplish the required project execution in the allotted time and on framed expenses. Certainly, some outstanding quality and construction management procedures were implemented in the past, and someone was present to supervise the resources and time schedule. In today's construction project management, many mathematical tools and techniques such as bar charts, CPM, PERT, and so on are employed for project planning. To manage the multi-tasking and complicated building environment, other standalone computer software and web-based packages are also in use. This paper aims to investigate advancements in construction management when dealing with extremely complicated building procedures in a complex environment. The methodology applied is to study and cite the literature of various preferred software management tools in the construction industry with the sequential order of the year, purpose, uses and process of the particular software. The results obtained are the analytical study of the software tools used in the construction industry.

ABSTRACT. Thermal cracks can occur in concrete elements at early stages during the hardening process. Also, the impact of thermal contraction and drying and autogenous shrinkage, may lead to excessive tensile strains and as a result cracks will occur. Consequently, an increase in reinforcements may be required to satisfy Early Thermal Cracking (ETC). ETC remains a major concern for concrete structures, especially for structures with high demand of water tightness. Considering the significance of water leaking in underground structures and the rising of the groundwater table in Qatar in the recent years, the Public Works Authority (ASHGHAL) have set criteria to control early thermal cracks for Highway and Drainage Structures. This paper aims to present a comparison between the Early Thermal Cracking (ETC) codes and guidelines aiming towards providing sustainable and efficient design. This study compares the design method and parameters considered in BD 28/87, CIRIA C660 and CIRIA C766 currently used in Qatar for ETC calculations such as crack width permissible limit, minimum area of reinforcements, temperature change at early age, long term ambient temperature, autogenous shrinkage, drying shrinkage and restraint conditions. In addition, ETC calculations are carried out for a tunnel reinforced concrete box section with wall and top slab thicknesses ranging from 300mm to 1000mm. The least required area of reinforcements (A_s,req) for wall subject to edge restraint was by CIRIA C766 and for top slab subject to end restraint was by BD 28/87.

ABSTRACT. Mesaimeer pedestrian Underpass is proposed under the live traffic of Sabah Al Ahmad Road, Doha, Qatar which consists of a four dual lane carriageway, in addition to diverge lanes, service road lanes and right turn lane by box jacking/pushing method for a total distance of 80.6 m. Due to the necessity of maintaining undisturbed traffic and to avoid disruption of the existing utilities crossing over the underpass alignment, the use of conventional Cut and Cover method is not feasible. Accordingly, trenchless construction method by box jacking/pushing is to be implemented in weathered limestone rock overlaid by made ground. The method of construction of box jacking includes constructing shaft as launching pit for jacking operation, aligning the precast concrete box into position, excavating the soil/rock at the face of the precast concrete box, then pushing the box into the excavated length, and repeating the process. This paper includes overview of the project and its challenges intending to bring greater familiarity with the box jacking process in rock formation. The design and anticipated construction challenges are discussed from both structural and geotechnical perspectives. The faced challenges include box segment protection details, waterproofing details, construction and expansion joint details, high jacking loads due to rock formation, excavation advancement rate, necessity of grouting at box over-head and impact on existing utilities. Both structural and geotechnical analysis/design are assessed by numerical finite element modelling (FEM). Further, instrumentation and monitoring measures are planned to monitor various utilities and assess the impact during construction. 

ABSTRACT. Biomaterials are considered as one of the materials that can be used as a partial replacement for petroleum-based asphalt to produce durable and safer pavements. This study investigates the high-temperature performance of bio-modified asphalt binders (BMB) using data seed oil (DSO). The BMBs were prepared using five volume ratios of 1.5%, 2.5%, 3.5%, 4.5%, and 5.5%. The performance of the control and modified asphalt binders was evaluated using Brookfield rotational viscometer (RV) and Dynamic Shear Rheometer (DSR) devices. Results showed that the addition of 1.5% DSO can restore the viscosity of the asphalt binder as the viscosity was reduced by 14.8% compared to the control binder. The rutting parameter (G*/sin δ) decreased with the increase of bio-oil at all temperatures. However, the nonrecoverable creep compliance (Jnr) obtained through multiple stress creep recovery (MSCR) test indicates improvement in resisting repeated loads. The traffic level was enhanced by the addition of 2.5% DSO to tolerate heavier traffic than the conventional asphalt binder.

ABSTRACT. The Cut and Cover construction method has been applied to build several underpass structures within the expressway programme of the highway projects department, Public Works Authority, Qatar. Booming in the construction industry contributes to increasing existing traffic in Qatar. This subsequently failed existing road junctions and required updating the road network parallel to the traffic studied. Underpasses and Bridges were planned across many locations in Qatar to increase the level of service at road junctions, enhance the traffic capacity, reduce traffic congestion, and improve the free flow of traffic. This paper discusses the design and construction challenges of the underpass structure constructed by top-down construction method located on D ring Road in Doha, Qatar. The top-down construction method has been suggested by the construction contractor as an alternative to the conventional cut-and-cover construction method to minimize the traffic disruption and meet updated temporary traffic management (TTMs) due to underpass construction works, restore traffic at the junction on top of the underpass prior to the completion of construction works and overall optimize the construction duration. A numerical modelling study was carried out to study the change in arrangements. The site-specific challenges, such as modification in the structural arrangement of the underpass, change in ground conditions, lateral displacement of pile walls and dewatering challenges, are discussed in this paper.

ABSTRACT. Driven by Qatar National Vision 2030 and catering to the 2022 FIFA World Cup, Qatar is undertaking an extraordinary and ambitious programme of infrastructure development to deliver a world-class new and upgraded road infrastructure network. Projects designed to improve highway capacity, connectivity, and safety through the urban and rural parts of Qatar and to meet current and future demands of population and economic growth. In this paper, the authors discuss some of the most critical and challenging considerations in putting a planning and design process on a path to successfully deliver a bridge deck widening project, implementing a collaborative approach. The case study of upgrading an existing ramp bridge will be presented, where the one lane deck was converted to two lanes to accommodate the heavy traffic flow. The fast-track construction schedule necessitated the widening from one side by 1.15m, while the extended slab was supported on a steel strut connected monolithically on the concrete box girder web (bottom) and extended part (top) through shear dowels. To meet the tight construction schedule and the local market material constraints, built-up sections were utilized with variable configurations along the length of the bridge. Further, several epoxy resin products were studied and utilized for the drilled bars on the extension part and the drilled dowels of the web. The replacement of the existing bearings was necessitated due to the additional weight of the extension.

ABSTRACT. Doha, the capital of Qatar, has been facing phenomenal growth of vehicular traffic with a parallel growth and rapid development of infrastructure and this resulted in an array of traffic congestions, significant rise of travelling time in some areas, etc. To mitigate these problems, upgrading existing intersections and consequently retrofitting the contained structures along significant corridors is a strategy implemented by the Authority in some cases. A case study presented herewith, is a project awarded as a Design & Build Contract by the Public Works Authority (PWA) to upgrade the infrastructure at the junction of a major corridor (Junction 101 – Industrial Interchange). The paper covers the tender stage and the final design solutions, outlining the simulation models, the assess of the existing structures, the design analysis and the construction methodology adopted to address the operation and maintenance conditions as well as the project specific requirements and constraints.

ABSTRACT. The mechanical study was carried out on fiber-reinforced concrete (UHPC) with two types of additions (metakaolin and silica fume) under heat treatment (90°C and 150°C). The study focuses on resistance to compression, 3-point bending and direct traction. The results show that dune sand is a very promising material since it makes it possible to obtain both a very good fluidity of UHPFRCs and also better mechanical resistances when it is associated with metakaolin. Its behavior with respect to stoving is also very favorable, with all the results obtained in compression exceeding 200 MPa. The deferred deformation tests, carried out on the same concretes, consisted in monitoring the evolution over time of the free deformations and the deformations under load in endogenous and desiccation conditions. The results obtained show that dune sand tends to slightly increase delayed deformations while metakaolin tends to decrease them (compared to silica fume). However, in all cases, the values obtained are very low and in agreement with the literature data on comparable materials. All the UHPCs tested also show little sensitivity to desiccation, which is a favorable element for their development. These tests highlighted the problem posed by the decoupling of the various deformations which leads to obtaining a negative desiccation creep. They also showed that, even in a severe water environment (RH of 50%), UHPFRCs, and mainly those based on dune sand, could fix certain humidity.

ABSTRACT. In the past decade, Doha the capital city of Qatar has witnessed a massive shift in various fields including economy, education, and sports sector. This flux caused rapid population growth, and as a result have led to an increase in the number of private cars in the city, leading to significant traffic congestion. The Transport Master Plan for Qatar (TMPQ) 2006-2026 includes the introduction of a metro and rail system aiming to (1) solve the problem of traffic congestion, (2) meet the goals of Qatar National Vision (QNV) 2030, (3) and successfully sponsor the upcoming World Cup 2022. Most of the people in Qatar have private cars, which they generally consider necessary for door-to-door trips. In addition, the existing public transportation system is mostly used by the lower class. Therefore, in order to develop a successful public transportation system, it is crucial to examine people’s thermal perception of outdoor spaces, particularly in terms of microclimate, and people’s adaptive actions in response to Qatar’s hot humid climate. In this research paper, the thermal comfort issue was explored by considering both, subjective and objective parameters. The outcomes of the research reveal that people are largely able to adapt successfully to the heat through behavioral adaptation, which improves people’s thermal tolerance to the outdoor climate in Qatar. However, the findings indicate that people’s thermal comfort could be further enhanced through minor modifications to the outdoor environment including a high Height/Width ratio, provision of vegetation, and shading street furniture.

ABSTRACT. This case study addresses peak hour traffic timing in Qatar after COVID-19 as traffic conditions returned to normal. Traffic data were provided for multiple areas, mainly around Doha City. Flow data were obtained from traffic signal detectors for 318 intersections. The peak periods in morning, mid-day, and evening were 06:30–08:30, 12:30–14:30, and 17:15–19:15, respectively. These findings align with the Ministry of Transport’s state-wide study (Transportation Masterplan for Qatar) conducted in 2018. We found traffic in Qatar to differ on Thursday, Friday, and Saturday versus the rest of the week due to the weekend effect. Results offer useful insight for policymakers to reduce congestion and provide complex traffic solutions (e.g., understanding land use–specific peak hour timing, imposing zone-specific working hours). In addition, this case study highlights the potential to use existing infrastructure to expand traffic studies in Qatar at minimum cost.

ABSTRACT. Sports facilities and stadiums are built for a specific function and purpose. Once the demand for such purpose no longer exists, it is important to know how both the buildings and the city will adapt to the existence of such megastructures as to prevent turning them into ‘white elephants’ in the city. This paper aims to study the environmental impact assessment tools and techniques used in promoting and implementing sustainability in mega sports projects in Qatar. The investigation focuses on assessing the cultural impact of the architectural design of sports facilities in Qatar using the global sustainability assessment system (GSAS) as a sustainability/EIA assessment tool. Most of the stadiums and sports facilities in Qatar are GSAS-certified at the design and build (D&B) level and are ongoing their operational assessment. Data collection involves direct site surveys and visits, interviews, and meetings with the local authorities responsible for directing the works on the site, with the literature continuously reviewed. The findings of this paper include an objective overview of the global sustainability assessment system (GSAS) and its linkage to holistic sustainability. The recommendations involve the inclusion of mixed-methods analysis to integrate the long-lost concept of ‘culture’ in the realm of sustainability to prove that behind the modern exteriors of these newly-built structures lies a deep culture and a vernacular tradition. This study would be a significant milestone in the region and worldwide and a promising overview of utilizing local tools on an international level.

ABSTRACT. The urban form of Doha city has undergone numerous changes owing to rapid economic growth during the past few decades. The Qatar National Vision 2030 highlights environmental sustainability as one of the key sectors of Qatar’s First National Development Strategy. Achieving environmental sustainability requires analysis from meso and micro levels of perspectives. This study selected a low-rise neighbourhood (Onaiza) and a high-rise neighbourhood (West Bay) in Doha city to be analysed. The study objectives are to a) investigate environmental factors based on two levels: meso (walkability, backyard farming, waste management) and micro (surroundings, mobility, green infrastructure), b) comparative analysis between the two selected neighbourhoods and c) develop planning strategies to enhance the environmental sustainability in both low-rise and high-rise neighbourhoods. The research tools include content analysis, observation study and open-ended interviews. The results revealed similarities in lifestyle preferences for meso parameters walkability and waste segregation. However, backyard farming is preferred by low-rise neighbourhoods compared to high-rise neighbourhoods, due to the availability of space. While people’s lifestyle preferences for micro parameters, surroundings and green infrastructures have shown similarities, preference for mobility has different responses due to the opportunities in neighbourhoods. The study emphasizes the importance of public awareness and participation in formulating urban policies due to the changing dynamics of the city’s population.

ABSTRACT. We conducted thermal comfort field surveys in female educational spaces in Qatar in the autumn and winter of 2018 and 2020 – 21 and collected 324 datasets. They contained all the four environmental measurements and simultaneous thermal responses of female university students dressed in traditional Islamic clothing consisting of headgears and full-body cloaks (abayas) (mean clothing: 1.21 clo). Exacerbating the occupant discomfort, classrooms are overcooled/overheated in autumn/winter respectively. About 89.9% respondents had no access to indoor temperature control and 43.5% had no access to any environmental controls. We evaluated the mean indoor comfort temperature as 22.9 (3.1) ˚C. In 64.2 % cases, it did not conform to the comfort zone in international standards. We noted significant seasonal differences in indoor environments. Air speed was zero most of the time. Only 53.8% felt comfortable thermal sensations, and 66% accepted the environments, as against 80% in the international standards. The predicted mean vote (PMV) was significantly inaccurate up to three scale points and in 86.4 % cases PMV mis-predicted by half a scale point or more. Therefore, framing the narrative around user-controlled air movement and indoor controls is necessary, so that indoor temperature can be effectively increased in autumn and lowered in winter.

ABSTRACT. The street networks occupy 25% of land use and are the veins of cities. By 2050, more than two-thirds of the world's population will live in urban areas. The urban street infrastructures and systems are expected to serve the public in performing mandatory and social activities on the streets. In addition, walkability and mobility within urban streets are linked with better public health demands. Therefore, there is a need for the public street to adopt smart features to provide better public health towards limiting the spread of covid. The study aims to develop a framework for smart street strategies to facilitate post covid built environment. The study adopts an integrative approach to deduct the smart street features through a robust literature review and workshops that influence post covid built environment within the urban design (Infrastructure) and information management. The study objective includes identifying the processes for adapting smart street strategies and healthcare concerns that can be leveraged to support public health in cities. As a result, the strategy can be adopted and applied by policymakers for implementation worldwide. The contributing features of the effort will focus on tracking, controlling, and preventing analogy. As a result, the framework will provide a baseline for neighborhoods, communities, and cities to develop and integrate novel strategies for managing public health to have an effective and efficient post-covid pandemic- built environment.

ABSTRACT. River front project at Patna, India along the river Ganga has rejuvenated the linear city of Patna, India. Patna is a historic city having lived for more than two thousand years. The city has grown linearly on the bank of Ganga. Like other cities of India, it faces the problem of pollution, congestion and lack of public open spaces and recreation spaces. After the completion of River front project, this city has got a new life. Once neglected and treated as back yard of city, it has opened up for the residents and has added new avenues of urban open spaces. It has added the recreation space to the city and the happiness index of the city will certainly rise. This paper examines the positive aspects of River front development in the city and how the residents have reacted to it.

ABSTRACT. Qatar is a water scarce country that heavily relies on seawater desalination. Multiple studies have concluded the need for a more resilient water planning through efficient “demand control” strategies. This study is among the very few attempts to “quantify” the actual impact of such solutions on the water sector. The purpose of this work is to generate “indicative” water usage figures to inform the (non-technical) decision makers and prove the benefits of shifting toward demand-based water strategies. A scenario-based approach was adopted, considering: maintaining status quo (scenario 1), improving the water pricing system (scenario 2), and regulating greywater reuse (scenario 3). Scenario 2 estimates the impact of water tariff increase based on Price Elasticity of Demand in neighbouring countries. Scenario 3 considers imposing on-site greywater reuse as part of the permitting process (for new constructions only). The study forecasted, up to year 2100, the impacts of demand control measures on: (1) domestic water consumption, (2) volume of desalinated water, (3) year by which additional desalination capacity is needed, and (4) year by which wastewater treatment facilities need expansion. It was shown that, by improving the water tariff system, the total domestic water consumption is reduced by up to 27% (equivalent to 16-19% reduction in total demand for desalinated water). As a result, the need to expand the water desalination facilities and the wastewater treatment infrastructure is delayed substantially: 15-20 years and 15-30 years, respectively. Also, regulating greywater reuse may reduce domestic water consumption by up to 6%.

ABSTRACT. The main technologies used in Gulf Cooperation Council (GCC) based commercial-scale desalination plants are categorized into two groups: the thermal-based (mainly multi-stage flash distillation, MSF and MED) and membrane-based (mainly reverse osmosis). Presently, the GCC countries are in a process of modifying their existing desalination plant partially or entirely by reverse osmosis process technology. In the desalination plants, 40.0 percent of the feed water will be drinkable water and the remaining 60.0 percent will be the discharge brine. The disposal of brine and wastewater is significant for the Arabian Gulf. This study presents GCC desalination capacities trend and electricity demand trend, GCC Unified Water Strategy and discuss the developing technologies, which are promising considering the environment. In this study, several emerging technologies for brine management, such as greenhouse desalination, pressure retarded osmosis system, different hybrid systems such as electrodialysed-based and reverse electrodialyzed-based hybrid systems have been analysed. From our study it was found that the new strategies examined here are suitable and beneficial for energy consumption decrease as well as environmental sustainability of desalination plants. However, we recommend that additional studies are essential on a commercial scale for assessing the efficiency, suitability and sustainability of these technologies. We also recommend that more studies must be focused towards using the most accessible renewable energy in the GCC countries, such as wind energy, solar energy, etc., and for techniques which cause minimum impact on the environment.

ABSTRACT. A rapid rise in demands for thermal comfort in the building sector necessitates higher energy consumption for air conditioning, ventilation, space, and water heating systems. Recently, phase change materials (PCMs) have gained much attention from researchers for passive heating/cooling of space and water. PCM can store/release thermal energy as latent heat during its phase change process isothermally. Moreover, PCM facilitates solar energy harvesting by photothermal conversion and storage. However, major limitations of PCM include low thermal conductivity, leakage during phase change, and lack of photoabsorbance. Therefore, in this study, the shape-stabilized phase change composites were prepared by melt blending of Paraffin Wax (PW), Tetra Pak (TP), and expanded graphite (EG). PW is an organic PCM, widely being studied due to its high enthalpy, availability at various melting points, and chemical and thermal stability. In addition to providing shape stability and thermal conductivity enhancement of PCM, the usage of TP promotes the recycling of TP waste into useful products. The addition of EG contributes to the thermal conductivity increase of 3.6 times that of pure PW. Moreover, the excellent photoabsorption of EG and TP effectively converted the photo energy to thermal energy and stored it as latent heat by PW in the composite. Two types of composites using PW of melting points 44 ℃ and 64 ℃ were exhibited a photothermal conversion and storage efficiency of 80 and 55 %, respectively and which is promising for solar water heating applications.

ABSTRACT. The Environmental Protection Agency's (EPA) Storm Water Management Model (SWMM) is a dynamic hydrologic-hydraulic model that simulates the amount and quality of runoff from urban areas. It is broadly used for planning, analyzing, and designing stormwater runoff, combined and sanitary sewers, and other urban drainage systems. SWMM can solely be used to do the modeling of urban drainage systems. However, SWMM can be automated and convert model files to and from GIS data using R programming, allowing for more in-depth analysis and visualization. Automatic calibration is also a promising alternative, ideally supporting a user-independent and time-efficient method for estimating model parameters. This study investigates the impact of Land Use and Land Cover (LULC) variation on peak discharge at the outfall of the Najafgarh-Mahipalpur drain during rapid urbanization from 2005 to 2022. The findings show that the historical LULC fluctuation for seventeen years resulted in a nearly 28% rise in the peak flow rate at the outfall, according to SWMM simulation. The findings of this study could serve as a guide for planning and managing urban flooding in cities that are rapidly expanding, particularly in developing countries.

ABSTRACT. Due to the expansion of industry, the world's population growth has led to increased air and water contamination. Because they are poisonous and non-biodegradable, organic dyes are a significant source of this contamination. Studies have concentrated on photocatalysts to transform organic dyes into innocuous compounds in order to lessen the harm that organic colours cause. In this study, A straightforward and inexpensive solution combustion technique was employed to prepare rare-earth metal (Tb) to be doped into the lanthanum silicate phosphor (La10Si6O27) using lanthanum nitrate and fumed silica were utilized as precursors, oxalyl di-hydrazide (ODH) was used as fuel, and terbium nitrate was employed as a dopant precursor for the. The photocatalytic activities for the Direct Green-23 (DG-23) dye degradation under UV irradiation were also assessed. These findings support the prepared nanophosphors are promising candidates for waste water treatment applications

ABSTRACT. The environmental degradation of our time, the environmental devastation of previous years and global warming have presented the world with new and novel challenges that were not experienced in previous decades. Rising sea levels, increasing energy demand and the explosion in energy prices have created new focal points in the thinking of all spheres of economic life. The environmental degradation of fossil fuels has led to an increasing focus on renewable energy sources and innovative solutions. The aim of this paper is to examine the main issues outlined above through the examples of two flagship megaprojects. The study will examine the Maldivian floating city and the European Energy Island project from a user perspective, specifically in terms of their environmental and visionary messages. In this study, we will examine the two flagship projects through the results of a primary research, formulating the main messages for the design of the future projects. The aim of the study is to demonstrate the importance of environmental considerations in the definition of project scope, in order to give a starting point for projects with similar objectives, and to give ideas for their design and implementation. The acceptance of any project by its users is a key success factor, as the two projects under review are intended to demonstrate.

ABSTRACT. The demand for the development of fiber reinforced composites has enhanced as the practise of integrating fibres into concrete has become prevalent over the past few decades.. The intersection zone where the fiber crossing the fracture surface and fiber distribution characteristics in the composite plays an important role in predicting the overall performance of the Fiber Reinforced Composite (FRC). To ascertain the orientation and distribution of the fibres in various FRC's, a variety of experimental methods have been proposed in the literature. This study aimed to assess the impact of fibre orientation and fibre distribution characteristics on the fresh and hardened properties of Hybrid FRC's and Hybrid Graded FRC's containing glass and steel fibres. It can be concluded that the methods adopted in this study for calculating the fiber distribution and orientation characteristics were reliable and the proposed equations were successful in predicting the uniaxial behaviour of FRC. Positive synergy was observed in the Hybrid Graded FRC specimens, which was attributed to the superior fibre distribution characteristics displayed by hybrid grading of fibres, which was rationalised by the fact that modifying the fibre distribution characteristics would affect the FRC’s behaviour.

ABSTRACT. In this work, the static and free vibration analysis of functionally graded (FG) porous beams is investigated using a new higher-order shear deformation model (HSD). The porosity which develops naturally during the fabrication of a material is arbitrary in nature. Therefore, in the present study, a variation is considered taking into account three distribution patterns, namely (i) even distribution, (ii) uneven distribution, and (iii) the logarithmic-uneven pattern. Furthermore, the impact of several micromechanical models on the bending and free vibration behavior of the beams was investigated. Different micromechanical models were used to examine the mechanical properties of functionally graded beams, the properties of which change continuously throughout the thickness following a power law. Using the HSD model, the equations of motion are obtained using Hamilton’s principle. To obtain displacements, stresses, and frequencies, the Navier type solution method was employed, and the numerical results were compared to those published in the literature. The impact of porosity and volume fraction index, different micromechanical models, mode numbers, and geometry on the bending and natural frequencies of imperfect FG beams were investigated.

ABSTRACT. This study applies Response Surface Methodologies (RSM) methods to maximize 3D-Printed clay mechanical properties. Mixes containing different Graphene Nanoplatelets (GNPs) content were printed and tested in compression and flexure. The Central Composite Design method was used by coding the mixes fabrication method, i.e. moulding and printing, and GNPs content as variables. The analysis showed that the mixes containing low GNPs content of 1 wt.% attained higher compressive and flexural strengths than those containing a higher content of 2 and 3 wt.%. The results also highlighted that GNPs' efficiency was better observed in the printed samples other than the moulded ones, indicating that the printing process contributed to a better and more uniform dispersion of GNPs in the clay matrix. RSM analysis confirmed that the maximum flexural strength response could be obtained using a GNPs content of 1 wt.%. Furthermore, the desirability analysis showed that a maximum predicted flexural and compressive strength improvements of 21 and 36 % compared to the control mixes could be obtained, respectively. In summary, this study proposed the importance of using nanofilaments in 3D printing activities to achieve the desired elements' mechanical properties.

ABSTRACT. Every year, many researches are presented in relation to seismic hazard analysis and new methods of earthquake hazard zoning, but so far, no general studies have been done to calculate the earthquake hazard zoning maps of all regions of Iran. Therefore, it is necessary to know new methods that can update seismic hazard maps for Iran based on the solutions presented in these sources. By reviewing several standards (ASCE 07, UBC-97, API650, IBC, 038),the results of Seismic hazard assessment in each of these sources have been compared with each other by Site Specific Probabilistic Seismic Hazard Analysis on site 2 of South Pars. By using geological maps around the site with a radius of 150 kilometers, the information about the seismicity of the region was collected. During the field visits, the faults in the area were identified and their characteristics were determined and based on the tectonic conditions, seismotectonics of site, active faults in the site, faults mechanism, the geometry of seismic zones Seismic parameters were determined. Therefore, the PGA and the design response spectrum for different seismic levels have been determined. The Seismic hazard assessment in ASCE7-5, UBC-97, 038, API650 is for return period of 475 or 2475 years (probability of uniform collapse assuming that there is no uncertainty in the collapse capacity of a structure), But in ASCE 7-10, Seismic hazard assessment based on the risk-targeted concept leads to the design of structures with the uniform hazard of collapse (there is uncertainty in the collapse capacity). Therefore, due to the use of the new concept in relation to the Seismic hazard assessment in the ASCE7-10 standard compared to other standards, this regulation has relative superiority and more valid results

ABSTRACT. This paper presents the test results of a study on the bond performance of near-surface mounted (NSM) basalt fiber reinforced polymer (BFRP) bars to concrete. Twelve C-shape concrete specimens were tested under direct pullout loading configuration. Test parameters included the bar surface configuration (deformed and sand-coated), the types of epoxy adhesive (NSM gel and Sikadur-30), and the bonded length (6, 12, and 24 times its diameter). The influence of various parameters on the overall bond performance of NSM-BFRP bars is analyzed and discussed. The obtained results confirmed the impact of the investigated parameters on the bond behavior of the tested specimens. It was found that the bond strength and failure mode varied considerably with the bar surface configuration and bonded length. Higher bond strength was obtained when the NSM Gel epoxy with high strength properties. The results also revealed that both the deformed and sand-coated bars showed almost similar bond strengths. Moreover, the pullout loads increased with the increase of the bonded length of the NSM bars.

ABSTRACT. Many engineering applications, such as wind energy distribution for optimum site selection for wind farms, pollutant dispersion, forest fire propagation and wind loads on structures in hilly terrains require a thorough understanding of the wind flow. The assessment of wind loads on buildings and structures located on exposed hill sites is a key application of understanding the effect of topography. This paper presents a wind tunnel investigation of along-wind aerodynamic forces on a rectangular plan building located near and on top of a gently sloped sinusoidal hill. The hill model has a slope equal to 15° and extends fully across the width of the wind tunnel in the direction perpendicular to the wind flow. A Force measurement study is carried out on a rectangular plan rigid building model which is placed near and on top of the hill at a total of 17 successive locations. Results measured include along-wind base shear forces and base moments. It is observed that the along-wind force gradually increases as the building is moving closer towards the crest. The maximum along-wind base shear force for the building is reported just upstream of the crest. Increased along-wind base moment for the building up to a factor of 4.0 is observed at the crest. This paper is expected to be of great help to structural engineers designing buildings in hilly terrains.