Construction Technologies and Architecture Vol. 13

Abstract: This study aimed at development and application of a numerical model; WHPANM (Water Hammer Phenomenon Analysis Numerical Model), to investigate the water hammer phenomenon in the penstock of the Keyal Khawar hydropower plant in Khyber Pakhtunkhwa, Pakistan. The model, written in Visual Basic, utilized the numerical method of characteristics to solve the momentum and continuity water hammer equations. Results indicated that using a 2.2 m diameter pipe resulted in a maximum and minimum pressure head of 1462 m and 1420 m. Increasing the diameter to 3.0 m decreased the maximum pressure head to 1448 m, while the minimum pressure head increased to 1422 m. Conversely, decreasing the diameter to 1.0 m led to a maximum and minimum pressure head of 1522 m and 1363 m, respectively. Regarding pipe length, a standard length of 900 m maintained maximum and minimum pressure heads at 1462 m and 1420 m, respectively. Extending length to 1400 m increased maximum pressure head to 1485 m. Conversely, shortening length to 300 m resulted in a decreased maximum pressure head of 1436 m, with minimum pressure head remaining constant at 1420 m. To prevent water hammer damage in high head hydropower plants, study recommends utilizing a 2.2 m diameter penstock pipe and coordinating valve closure times accordingly. The study suggests a systematic design approach, optimal penstock diameter, and less rigid pipe materials to mitigate water hammer effects. The WHPANM model demonstrated strong concordance with the original data generated by the commercial software employed by the consultant for the Kyal Khwar hydropower plant.

Abstract: Following the Kashmir Earthquake on October 8, 2005 attention is being paid to the seismic vulnerability on a national scale. There is an urgent need to check the bridge structures in earthquake-prone zones of Pakistan. In order to address this problem, this research aimed to perform a progressive pushover analysis of a reinforced concrete bridge of Pakistan and to check the seismic capacity of the under-investigation bridge to ensure the seismic demand of the area. The modelling and analysis of the existing bridge within the seismic zone 3 of Pakistan was carried out using computer-aided software CSI Bridge. Pushover analysis was conducted at different drift levels to assess its seismic demand and capacity across various seismic zones. The research concluded with an overview that bridge was able to achieve the life safety stage and it can sustain the earthquake acceleration in the seismic zone 3 of Pakistan. Lastly, recommendations measures for the under-investigation bridge were developed.

Abstract: To alleviate the corrosion issue, GFRP bars are usually preferred over steel reinforcing bars. However, its application causes larger deflection and brittle failure of concrete members. To solve this, steel bars can be used in combination with GFRP bars to reduce deflection and enhance ductility. Steel-GFRP hybrid reinforced concrete is a relatively recent concept, as a result, it is still in the development stage. This study numerically examines the flexure response of concrete beams reinforced with hybrid reinforcement i.e., GFRP bars combined with steel. A total of five numerical models were developed for this investigation. The analysis methodology is based on the models developed for investigation of GFRP reinforced concrete beams which was validated with experimental studies. It is found that with an increase in the replacement percentage of steel in GFRP RC beams, the ultimate load is increased. Also, it is observed that there is a significant reduction in deflection in post-cracking and pre-steel yielding region along with enhancement in the attributes of ductility which is beneficial for serviceability aspects. The steel-GFRP hybrid-reinforced concrete beams were found to have failed by yielding of steel and subsequent concrete crushing.

Abstract: Public transport is a vital infrastructural facility that must be contiguous for the public to use. Orange Line Metro Train Service has improved the public transportation facility in Lahore. To evaluate its performance, a study is conducted on students of the University of Engineering and Technology. Four dependent variables were selected for the study; time, comfort/ convenience, safety/ security, and economic feature. A survey was conducted and results were evaluated using Cronbach’s Alpha value on dependent variables. Correlation analysis and basic statistical analysis were also used in data analysis. It was found that gender has no significant difference in the perception of comfort/convenience features. Additionally, it was found that comfort significantly impacts a person’s reuse of OLMRTS compared to other variables due to the high Cronbach’s alpha value.

Abstract: Road defects are inevitable in the infrastructure of any city but its effects on the safety of road users and overall economy vary. There are several factors which contribute towards the magnitude and frequency of such defects and how much human and financial loss they incur. Finding suitable solutions to these road defects which are cost effective as well as sustainable are necessary. This study aims to explore the various common road defects, their cause and possible sustainable solutions. Different localities in the city of Karachi were selected for estimating the average frequency and magnitude of common road defect types. It was found that on an average there were 2.8 potholes, 1.5 ditches, 1.68 speed breakers, 1.3 open manholes, and 0.16 open nullahs per kilometer in Karachi. All together they constitute about 59,436 road defects in the city of Karachi. The most hazardous of them are the open manholes which account for day to day fatal and severe injury accidents. Some of the solutions evaluated for the repair of these road defects were concrete debris, aggregate mixture (gherha), earthen backfill, and used rubber tire strips based manhole cover.

Abstract: The availability of fresh water in the required quantity is the major challenge in Karachi city. There is a need to evaluate the potential of available water resources and devise a suitable distribution mechanism for the city. This study aims to determine the current water situation of Karachi City and it predicts the future water situation till 2040 considering 30 gallons per capita per day (GPCD) as an annual requirement per person. The study is conducted with the help of WEAP software. WEAP software uses different scenarios to estimate future water needs. In the software, water needs of Karachi from 2020 to 2040 were assessed and analysis of water demand, unmet demand, supply delivered, and demand site coverage was carried out. During modeling, a growth rate of 2.31% per year was used. The result indicates that the water demand will increase to 759.064 million gallons per day (MGD) in 2040, so an extra supply of 336.564 MGD will be required to meet water demands and urbanization of the city. To meet this unmet demand, it is suggested that water leakage be reduced as proposed by the Karachi Water & Sewerage Board (KWSB). Moreover, water conservation techniques and the use of treated wastewater along with the existing water are recommended to reduce the unmet demand.

Abstract: Floating Vegetation Islands (FVIs) are commonly found on the shallow surfaces of open channels, such as rivers and canals. These FVIs can significantly alter the flow characteristics, causing changes in flow velocity and turbulence around the canopy zone. This research employs Computational Fluid Dynamics (CFD) modeling to investigate the impact of FVIs on flow velocity in an open channel. The numerical simulations were conducted using ANSYS-FLUENT software, utilizing the Reynolds Stress Model (RSM). Three patches of FVIs with a density of 2.0583/cm² were considered in the simulations. The findings demonstrate a substantial reduction in flow velocity, up to 100%, within the vegetation zone, while a velocity increase of 285% was observed in the free adjacent zone. A shedding behavior with large and turbulent wake structures was observed behind the floating patches, whereas a significant difference in the velocity magnitudes between the upper canopy part and the lower free part (water column) was observed. This study highlights the significant influence of FVIs on flow dynamics in open channels.

Abstract: The workforce shortage has become a critical issue in the construction industry in the United States, and many people believe that the shortage will be prevalent for years. The main reasons for the construction workforce shortage are the aging workforce and a lack of interest from young people in joining the industry. As educators in construction, we need to actively participate in events that provide opportunities to interact with children and young adults so that we can provide them with information about career opportunities in the construction industry and boost the image of the construction industry. Research studies show that kids start to make career choices when they are in 8^th or 9^th grade. Boosting awareness of construction career possibilities for kids in that age group is an important effort to attract young talent to the construction field. This paper describes an effort to provide early construction career exposure opportunities to K-12 students through an interactive career expo organized by a local non-profit organization.

Abstract: The Sustainable Development Goals (SDGs) were approved by the global community in 2015as a collaborative plan to achieve a sustainable future. The achievement of sustainable development goals needs successful global linkages and partnerships (SGD-17) that can organize resources, share technologies, knowledge, and collaborate efforts between countries and organizations. However, global partnerships and linkages experience several barriers and challenges that hinder their effectiveness and impede advancement towards digitalization, green technologies, and regional diversification. This research intends to make up this gap by addressing aforementioned problems through examining role of global linkages to achieve sustainable development goals, identifying the main challenges and barriers in achieving these objectives, and to recommend polices and suggestions to strengthen these linkages and maximize their impact. To achieve the objectives of the study, a thorough review of academic literature, government reports, industry databases and policy documents, questionnaire survey and expert interviews were carried out to understand the present level of knowledge about global linkages and sustainable development goals. The data was obtained by using well-structured questionnaires through experienced professionals working as academic research, government official, NGOs and private sector professionals working in the construction industry. An online questionnaire was floated among different groups from which 128 returned and 32 were rejected, as the respondents have no understanding about sustainable development. Mean Item Score through SPSS was used to analyze the data.

Abstract: The construction industry is crucial in driving Pakistan's economy and GDP development, heavily relying on its workforce. However, various challenges, such as cost, time, quality, and safety, can significantly impact construction projects. Understanding and enhancing construction productivity is essential for the industry's economic success. This study investigates the factors influencing construction worker [CW] productivity in the Quetta City construction industry through a comprehensive survey of 109 respondents, including CW, contractors, site engineers, and construction foremen. The factors are categorized into management-related, site-related, health, safety, and environment (HSE) and welfare-related and external factors. Water and power supply shortages emerged as significant management-related factors, while poor site layout and rework were prominent site-related influencers. Heat and cold stresses were identified as critical HSE-related factors impacting productivity, and economic conditions of the state and stakeholder's poor financial conditions were prominent external factors. The study provides recommendations to improve CW productivity by emphasizing job satisfaction, stable economic conditions, investing in training and development, and ensuring CW health and safety. In addition, further research could be carried out on productivity issues and rates, which can be compared with the case studies of developed countries to identify best practices for increased construction industry efficiency.