Nazam Ali
@hku.hk
Postdoctoral Fellow, Department of Civil Engineering
The University of Hong Kong
RESEARCH, TEACHING, or OTHER INTERESTS
Civil and Structural Engineering, Transportation, Automotive Engineering, Multidisciplinary
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Sameen Zafar, Muhammad Abdullah, Muhammad Ashraf Javid, and Nazam Ali
Elsevier BV
Muhammad Abdullah, Nazam Ali, Muhammad Ashraf Javid, Muhammad Waqar Aslam, and Charitha Dias
MDPI AG
Increasing vehicular demand has compelled decision makers to turn urban roads into signal-free corridors (SFCs) in Lahore. These corridors aim at prioritizing car flow over other modes and consist of various car-centric projects (CCPs), such as continuous flow intersections, grade separation, and continuous through movement. These projects often ignore pedestrian requirements and, thus reduce pedestrian safety. Considering the ongoing development projects in Lahore, this study aimed at evaluating the concept of SFCs. A total of 6 existing SFCs were identified in Lahore, which lacked basic pedestrian infrastructure. An expert survey was then conducted to understand the purpose of creating these SFCs, their effects on pedestrians, and the way forward. The thematic analysis regarding the purpose of creating these SFCs and their effect on pedestrians indicated the prioritization of private cars and pedestrian safety issues as the two underlying themes. A questionnaire survey was conducted to evaluate the perceptions of pedestrians on these two themes, i.e., pedestrian safety and car priority. Principle component analysis extracted two components labeled as pedestrian safety and car priority. Component scores were computed, and the three CCPs were then compared using non-parametrical tests in terms of both these components. According to the results, continuous flow intersections were declared to be significantly safer than continuous through movement and grade separation, whereas continuous flow intersection was found to be prioritizing cars over pedestrians significantly more than continuous through movement and grade separation. Finally, policy implications were presented for practitioners.
Panuwat Joyklad, Hafiz Ahmad Waqas, Abdul Hafeez, Nazam Ali, Ali Ejaz, Qudeer Hussain, Kaffayatullah Khan, Arissaman Sangthongtong, and Panumas Saingam
MDPI AG
Many masonry structures are constructed with cement clay interlocking brick (CCIB) due to its added benefits. Recent research has demonstrated the vulnerability of brick masonry walls against seismic loading. Various strengthening materials and techniques are extensively used to improve the structural behavior of brick walls. Carbon fiber-reinforced polymer (CFRP) composites are the most popular strengthening material due to their advantages of easy application, lightweight qualities, and superior tensile strength. The current research work aimed to explore the cost-effective solutions and feasibility of CFRP composite-based strengthening techniques to improve the load-bearing capacity of CCIB walls. Various configurations and combinations of strengthening materials were investigated to customize the cost of repair and strengthening. The experimental results indicated that CFRP composites in combination with cement-sand (CS) mortar are an efficient strengthening material to enhance the strength and ultimate deflection of CCIB walls. The ultimate load-bearing capacity and axial deformation of the strengthened CCIB wall (using two layers of CFRP strips and CS mortar of 10 mm thickness) remained 171% and 190% larger than the unstrengthened CCIB wall. The conclusions of this study are expected to enhance the seismic performance of masonry buildings in developing countries. It should be noted that due to the reduced number of tested specimens, the results to be assumed as general considerations need a wider experimental campaign and a large numbers of tests for each strengthening typology.
Panumas Saingam, Ali Ejaz, Nazam Ali, Adnan Nawaz, Qudeer Hussain, and Panuwat Joyklad
MDPI AG
Recently, hemp-fiber-reinforced polymer (HFRP) composites have been developed to enhance the strength and ductility of normal and lightweight aggregate concrete along with recycled brick aggregate concrete. In addition, both experimental and analytical investigations have been performed to assess the suitability of the existing strength and strain models. However, the theoretical and analytical expressions to predict the stress–strain curves of HFRP-confined concrete were not developed. Therefore, the main objective of this study was to develop analytical expressions to predict the stress–strain curves of HFRP-confined waste brick aggregate concrete. For this purpose, a new experimental framework was conducted to examine the effectiveness of HFRP in improving the mechanical properties of concrete constructed with recycled brick aggregates. Depending on the strength of the concrete, two groups were formed, i.e., Type-1 concrete and Type-2 concrete. A total of sixteen samples were tested. The ultimate compressive strength and strain significantly increased due to HFRP confinement. Improvements of up to 272% and 457% in the ultimate compressive strength and strain were observed due to hemp confinement, respectively. To predict the ultimate compressive strength and strain of HFRP-confined concrete, this study investigated several existing analytical stress–strain models. Some of the strength models resulted in close agreement with experimental results, but none of the models could accurately predict the ultimate confined strain. Nonlinear regression analysis was conducted to propose expressions to predict the ultimate compressive strength and strain of HFRP-confined concrete. The proposed expressions resulted in good agreement with experimental results. An analytical procedure was proposed to predict the stress–strain curves of hemp-confined concrete constructed by partial replacement of natural coarse aggregates by recycled fired-clay brick aggregates. A close agreement was found between the experimental and analytically predicted stress–strain curves.
Nazam Ali, Shoichiro Nakayama, and Hiromichi Yamaguchi
Elsevier BV
Muhammad Abdullah, Nazam Ali, Muhammad Ashraf Javid, and Qudeer Hussain
Elsevier BV
Panuwat Joyklad, Nazam Ali, Krisada Chaiyasarn, Suniti Suparp, and Qudeer Hussain
Elsevier BV
Tiziana Campisi, Nazam Ali, Kadir Diler Alemdar, Ömer Kaya, M. Yasin Çodur, and Giovanni Tesoriere
AIP Publishing
Tiziana Campisi, Nazam Ali, Nurten Akgün-Tanbay, Antonino Canale, and Giovanni Tesoriere
AIP Publishing
Nazam Ali, Muhammad Ashraf Javid, Tiziana Campisi, Krisada Chaiyasarn, and Panumas Saingam
MDPI AG
Ride-hailing services play an important role in developing countries where conventional transport systems are not enough to meet the needs of commuters because of increased populations. This form of transport has gained much popularity in developing regions because of the inclusion of motorcycles and rikshaws in ride-hailing services. To the best of the authors’ knowledge, there has been little research on passengers’ behavior towards these ride-hailing services that focuses on social protection and the fare system in developing regions. Therefore, this research study is aimed at investigating the behavior of commuters towards these ride-hailing services in Lahore, which is the second largest city in Pakistan and can be considered as a case study of a developing country. A total of 531 useable valid responses were collected through face-to-face interactions, including the sociodemographics (SEDs) and behavior of commuters towards these services. The results of an explanatory factor analysis (EFA) and structural equation modeling (SEM) revealed that some of the significant latent variables of these ride-hailing services are comfort, convenience, privacy and security, the fare system, social protection, and safety. The commuters’ overall evaluation of these services is positive and affects their present and future preferences. The structural coefficient between convenience and the variable of present preference is significant and negative, which shows that there are respondents who infrequently use ride-hailing services despite having high satisfaction. The riders’ satisfaction with privacy, security, social protection, safety, and comfort has a positive and direct impact on their present preferences as the structural estimates are positive, which means that the higher their views on privacy, security, and comfort, the more frequently they intend to use ride-hailing services for commuting. Increased social protection, safety, privacy, and security will improve the evaluations of the commuters and influence their present preferences for these ride-hailing services. Even though there are regulations on these ride-hailing services, some concrete policy interventions are needed for improvements in commuters’ overall evaluations of these services in order to influence their future preferences. The findings of this research study, if applied in the real world, can improve the overall evaluation of the commuters and positively influence their present and future preferences for these ride-hailing services.
Panuwat Joyklad, Panumas Saingam, Nazam Ali, Ali Ejaz, Qudeer Hussain, Kaffayatullah Khan, and Krisada Chaiyasarn
MDPI AG
Given the excessive demolition of structures each year, the issues related to the generated structural waste are striking. Bricks being a major constituent in the construction industry, also hold a significant proportion of the construction waste generated annually. The reuse of this brick waste in new constructions is an optimal solution considering cost-effectiveness and sustainability. However, the problems related to the substandard peak stress and ultimate strain of concrete constructed with recycled brick aggregates (CRAs) limit its use in non-structural applications. The present study intends to improve the unsatisfactory mechanical characteristics of CRAs by utilizing low-cost glass fiber chopped strand mat (FCSM) sheets. The efficacy of FCSM sheets was assessed by wrapping them around CRA specimens constructed with different concrete strengths. A remarkable increase in the peak compressive stress and the ultimate strain of the CRA specimens were observed. For low, medium, and high strength CRAs, the ultimate strain improved by up to 320%, 308%, and 294%, respectively, as compared to the respective control specimens. Several existing analytical models were utilized to predict the peak compressive stress and ultimate strain of the CRAs strengthened using FCSM sheets. None of the considered models reproduced experimental results accurately. Therefore, equations were formulated using regression predicting the peak stress and ultimate strain of the CRAs confined with FCSM sheets. The predicted values were found to correlate well with the experimental values.
Panuwat Joyklad, Nazam Ali, Krisada Chaiyasarn, Nakhorn Poovarodom, Ekkachai Yooprasertchai, Hassan M. Maqbool, Anat Ruangrassamee, and Qudeer Hussain
Elsevier BV
Muhammad Aslam, Muhammad Umer Shehzad, Ahsan Ali, Nazam Ali, Krisada Chaiyasan, Husnain Tahir, Panuwat Joyklad, and Qudeer Hussain
MDPI AG
The present study focused on the development and application of two computer numerical models, namely, a seepage model developed using SEEP/W software and a groundwater model developed using Visual MODFLOW software. The seepage model was applied to a 38 km length of the tail reach of the Trimmu–Sidhnai (T-S) link canal passing through a severely waterlogged area of 32,000 ha, with a water table within 0–1.5 m from the ground surface; this was to quantify the canal seepage under the present condition (without any intervention) and with the interventions of a concrete lining of the complete prism of the T-S link canal and concrete side protection of the T-S link canal, with the canal bed unlined. The groundwater model evaluated the effectiveness of three waterlogging management interventions, which included: (i) the rehabilitation of the 43 existing drainage tube wells, (ii) the rehabilitation of the existing surface drains, and (iii) a combination of the rehabilitation of the 43 existing drainage tube wells and the rehabilitation of the existing surface drains. The seepage modeling revealed that the concrete lining intervention can reduce 50% of the seepage of the T-S link canal, whereas the concrete side protection intervention can reduce only 21% of the canal seepage. The groundwater modeling revealed that the waterlogging management intervention of the rehabilitation of the 43 drainage tube wells and surface drains can lower the groundwater level from 139.2 to 138.3 m (0.9 m drop), resulting in the mitigation of waterlogging in 45% (14,400 ha) of the severely waterlogged area. The present study recommends that complete concrete lining of the T-S link canal has a huge potential to reduce seepage from the canal, and the combination of the rehabilitation of the 43 drainage tube wells and surface drains also offers a great potential for controlling waterlogging. This intervention can also be considered to mitigate waterlogging from the severely waterlogged area. Cost-effectiveness analysis of the concrete lining of the T-S link canal, the rehabilitation of the 43 existing drainage tube wells, and the rehabilitation of the existing surface drains need to be performed for decision-making and selection of the most cost-effective intervention for implementation. A study needs to be conducted for the development and evaluation of economical and socio-technically feasible and acceptable preventive waterlogging management interventions, including the improved management of irrigation systems, improved irrigation management practices at the farm, improved conjunctive management of surface and groundwater, and improved management of drainage systems at the primary, secondary, and tertiary canal command levels.
Suniti Suparp, Krisada Chaiyasarn, Nazam Ali, Chaitanya Krishna Gadagamma, Ahmed W. Al Zand, Ekkachai Yooprasertchai, Qudeer Hussain, Panuwat Joyklad, and Muhammad Ashraf Javid
MDPI AG
Intrinsically, lightweight aggregate concrete (LWAC) suffers from the low compressive strength and deformation capacity. This restricts the use of LWAC mainly to non-structural applications. Several studies have highlighted the potential of synthetic fiber-reinforced polymer (FRP) jackets for improving the substandard properties of the LWAC. However, the high costs associated with FRP jackets are generally a concern. This study identifies hemp fiber-reinforced rope polymer (FRRP) wraps as a potential alternative to the synthetic FRP jackets. The salient features of hemp FRRP include its low cost and easy availability. Therefore, the main question that needs to be answered is: can hemp FRRP strengthen LWAC as a low-cost alternative to synthetic FRP jackets? To quantitatively explain the effects of lightweight aggregates on concrete compressive strength, 24 concrete cylinders were tested in three groups. Group 1, 2, and 3 cylinders comprised 0, 50, and 100% of lightweight aggregates as natural aggregate replacements. The peak stress of the concrete was reduced by 34% and 49% in the presence of 50% and 100% lightweight aggregates, respectively. It was concluded that a single layer of hemp FRRP on Group 2 cylinders (i.e., 50% aggregate replacement) was sufficient to enhance the peak stress to the same level as that of the control cylinder in Group 1 (i.e., fabricated using natural aggregates only). At the same time, it took two layers of external FRRP on Group 3 cylinders to achieve the same strength. A positive correlation between the peak stress of the LWAC and the number of hemp FRRP layers was observed. Nonetheless, Group 1 and 3 cylinders formed the upper and lower bounds in terms of peak stress for the same level of confinement. Further to the interest, three layers of hemp FRRP shifted brittle compressive stress–strain response to a bi-linear response for all amounts of lightweight aggregates. Several existing analytical peak stress models were assessed in predicting the experimental results. From the results, it was inferred that none of these models predicted the compressive strength of all three groups of cylinders consistently.
Rattapoohm Parichatprecha, Kittipoom Rodsin, Krisada Chaiyasarn, Nazam Ali, Songsak Suthasupradit, Qudeer Hussain, and Kaffayatullah Khan
MDPI AG
Reusing construction brick waste to fabricate new concrete is an economical and sustainable solution for the ever-increasing quantity of construction waste. However, the substandard mechanical properties of the concrete made using recycled crushed brick aggregates (RBAC) have limited its use mainly to non-structural applications. Several studies have shown that the axial compressive performance of the concrete is a function of the lateral confining pressure. Therefore, this study proposes to use low-cost glass fiber-reinforced polymer (LC-GFRP) wraps to improve the substandard compressive strength and ductility of RBAC. Thirty-two rectilinear RBAC specimens were constructed in this study and tested in two groups. The specimens in Group 1 were tested without the provision of a corner radius, whereas a corner radius of 26 mm was provided in the Group 2 specimens. Specimens in both groups demonstrated improved compressive behavior. However, the premature failure of LC-GFRP wraps near the sharp corners in Group 1 specimens undermined its efficacy. On the contrary, the stress concentrations were neutralized in almost all Group 2 specimens with a 26 mm corner radius, except low-strength specimen with six layers of LC-GFRP. As a result, Group 2 specimens demonstrated a more significant improvement in peak compressive strength and ultimate strain than Group 1 specimens. An analytical investigation was carried out to assess the efficiency of existing compressive stress–strain models to predict the peak compressive stress and ultimate of LC-GFRP-confined RBAC. Existing FRP models were found unreliable in predicting the key parameters in the stress–strain curves of LC-GFRP-confined RBAC. Equations were proposed by using nonlinear regression analysis, and the predicted values of the key parameters were found in good agreement with the corresponding experimental values.
Suniti Suparp, Athasit Sirisonthi, Nazam Ali, Noha Saad, Krisada Chaiyasarn, Marc Azab, Panuwat Joyklad, and Qudeer Hussain
MDPI AG
Full-scale testing of multiple span girders is scarce in the literature, often related to the complexity of loading setup and time constraints. The importance of full-scale tests is manifested in the fact that useful information regarding failure mechanisms can be obtained. In addition, important guidelines can be established for structural designers. Further, results from full-scale tests can help establish constitutive laws for various mechanisms involved in the response of actual structures. The structural performance of individual members can be assessed by monitoring their strains at service and ultimate loads. This study presents a comparison of experimentally monitored strains on longitudinal steel bars, stirrups, and prestressing tendons embedded in single and multi-span full-scale precast pre-tensioned girders. These girders were constructed and detailed to simulate the response of newly proposed straddle-type monorail girders. Single-span girders were tested under monotonic two-point service and ultimate loads, whereas multi-span girders were tested under both two- and four-point service and ultimate load. It was revealed that longitudinal steel and prestressing tendon strains monitored within single-span girders at service and ultimate loads were significantly higher than those recorded at corresponding locations in multi-span girders.
Aida Mammadova, Nazam Ali, and Krisada Chaiyasarn
MDPI AG
Sustainability is one of the main global concerns to deal with and know-how about is it important for the unprecedented survival to cope with the social, political, economic, and energy scarcity issues. Higher institutions are important learning places which can play the role of transformation and create the opportunities and avenues in order to minimize the barriers towards more sustainable future. In this research study, an online training program for the understanding of Sustainable Development Goals (SDGs) and Sustainability was designed. Students from different Japanese and International Universities were invited for two weeks of training program. A Comprehensive questionnaire was designed in which students were introduced about UNESCO Biosphere reserves, SDGs, and different concepts of sustainability. The analysis of the statistical results confirm that the understanding of the students has improved after the online training program about SDGs and different aspects of sustainability. The results imply that the understanding of the international students about SDGs and sustainability is more as compared with the Japanese students. In 14 out of 17 SDGs, the familiarity of international students is more as compared with their counterparts. In this exploratory study, some of the challenges faced by the universities are also identified which impede the efforts for the implementation of goals and initiatives towards sustainable development. It has been concluded that the universities must design dedicated training programs to seize the opportunities for improving the understanding of the students and promotion of sustainable initiatives by using UNESCO Biosphere Reserves as learning platforms through innovation in teaching, research, and trainings. The possible limitations of this research study can be; (a) it involves the professionals about SDGs, which might have made the online training program as intensive one, giving some vague idea about SDGs and sustainability to the students, (b) though the personal information of the students were not gathered, however, the broader scope of the research study have provided strong international base which can be used as an adequate profile of sustainability and comprehension of SDGs currently being found in the universities. Design of practical implications is imperative for stimulating the creativity and autonomy about the comprehension of SDGs and sustainability to meet the demands of present and future challenges imposed for sustainable development.
Panuwat Joyklad, Ekkachai Yooprasertchai, Abdur Rahim, Nazam Ali, Krisada Chaiyasarn, and Qudeer Hussain
MDPI AG
Each year, massive amount of construction waste is generated that needs proper attention in terms of its disposal without deteriorating surrounding environment. A significant portion of this waste comprises bricks. Besides, large number of new construction works are resulting in the depletion of natural resources rapidly. Intuitively, a sustainable solution demands to consume this construction waste in the best way possible. This study targeted brick waste as a potential material to be used as a partial replacement of natural aggregates in structural concrete. It has been known that the concrete constructed with recycled brick aggregates possesses substandard mechanical properties. Traditionally, synthetic FRPs are known to strengthen recycled aggregate concrete. However, recognizing high costs associated with them, this study proposed the use of natural hemp fiber ropes to strengthen recycled aggregate concrete constructed with brick aggregates. To assess the efficacy of hemp ropes in strengthening mechanical properties of the concrete with coarse aggregates partially replaced with recycled brick aggregates (B-waste), an experimental framework was conducted. Sixteen cylindrical specimens were tested in two groups depending upon the concrete strength. Within each group, 2 specimens each were strengthened with 1, 2, and 3 layers of hemp fiber ropes. Axial monotonic compressive loading was applied to each specimen. Results revealed that hemp fiber ropes significantly improved ultimate compressive strength and the corresponding strain. A substantial improvement in axial ductility was observed. For the sake of performance-based non-linear modelling, accurate constitutive modelling at material level is necessary. For this purpose, several existing analytical stress-strain models were tested in this study to predict ultimate confined compressive strength and strain. It was found that several models predicted confined compressive strengths with reasonable accuracy. However, very few models were able to predict confined peak strain with good accuracy.
Suniti Suparp, Nazam Ali, Ahmed W. Al Zand, Krisada Chaiyasarn, Muhammad Usman Rashid, Ekkachai Yooprasertchai, Qudeer Hussain, and Panuwat Joyklad
MDPI AG
Salient features of lightweight aggregate concrete (LAC) include noticeable fire resistance, high strength-to-weight ratio, and low magnitude of dead loads. Further, LAC has a low cost, eases construction practices, and possesses an environment-friendly nature. On the downside, LAC has substandard mechanical properties in comparison to normal aggregate concrete. Natural fiber-reinforced polymers (FRPs) have shown their potential in ameliorating the mechanical properties of natural aggregate concrete. So far, no study has been conducted to assess the efficacy of hemp rope confinement to strengthen lightweight aggregate concrete especially comprising rectilinear sections. This study aimed to overcome the substandard nature of LAC. A low-cost, sustainable, and environmentally green solution in the form of natural hemp rope layers is proposed. Twenty-four square concrete specimens were tested in three groups depending upon the presence and quantity of lightweight aggregates. It was found that concrete constructed with lightweight aggregates demonstrated lower ultimate compressive strength and strain as compared to normal aggregate concrete. Hemp rope-confined LAC showed enhanced ultimate compressive strength and strain. This enhancement was found to increase with the number of hemp rope layers. Several existing ultimate stress models were assessed to predict the ultimate compressive strength of the hemp rope-confined specimens. Only a single model was able to predict the ultimate compressive strength of the hemp rope-confined specimens with reasonable accuracy.
Muhammad Ashraf Javid, Hanan Saif Al-Khatri, Sawsan Said Al-Abri, Nazam Ali, Krisada Chaiyasarn, and Panuwat Joyklad
MDPI AG
As everyone spends much time traveling, engaged in leisure or work activities, travel time represents one of the largest costs to transportation. The main objective of the study is to investigate travelers’ perceptions related to value of travel time saving with the help of a questionnaire survey. The survey was conducted online with the help of Google forms. The required data were collected through a self-reported questionnaire that consisted of five parts. A total of 312 useable sample responses were collected. The collected data were analyzed using conventional and statistical methods. In conventional methods, frequency distribution was carried out, and bar and pie charts were prepared. In the statistical methods, the exploratory factor analysis method (EFA) was conducted to extract useful factors affecting the travelers’ perceptions about travel time saving attitude. The survey results showed that more than 73% of people use a car for transport, which implies that most of them do not like to wait for public transport modes. It means that their travel attitudes are more inclined towards private transport seeking travel time saving. Most people do not like to share space with others while traveling, amounting to 44% of respondents using private cars alone, and placing high importance on flexibility, reliability, and time and cost saving in traveling, which implies that they are more likely to travel alone to save travel time. In addition, most of the respondents use short routes; this propensity is positively related to time and cost saving factors. Similarly, the time and cost savings and car-oriented attitudes are positively associated with the choice of a short route to save travel time. They also believe that the service quality level of transportation facilities affects the travel time saving and its value. This study proposes to improve travel time and cost in Oman.
Kittipoom Rodsin, Nazam Ali, Panuwat Joyklad, Krisada Chaiyasarn, Ahmed W. Al Zand, and Qudeer Hussain
MDPI AG
Several studies have highlighted the potential of crushed brick aggregates in non-structural concrete. This is because crushed brick aggregates offer substandard mechanical properties in comparison to natural stone aggregates. Synthetic Fiber Reinforced Polymer (FRP) sheets have been known to overcome this issue. However, enormous costs associated with synthetic FRPs may limit their use in several low-budget applications. This study recognizes this issue and propose a cost-effective solution in the form of low-cost glass fiber (LC-GFRP) sheets. Two types of brick aggregates (i.e., solid-clay and hollow-clay brick aggregates) were used to fabricate concrete by replacing 50% of natural aggregates. Experimental results of 32 non-circular specimens were reported in this study. To overcome the substandard mechanical properties of recycled brick aggregate concrete (RBAC), specimens were strengthened with 2, 4, and 6 layers of LC-GFRP sheets. Noticeable improvements in ultimate compressive stress and corresponding strain were observed and were found to correlate positively with the number of LC-GFRP sheets. It was found that 4 and 6 layers of LC-GFRP sheets imparted significant axial ductility irrespective of the brick aggregate type and inherent concrete strength. Several existing stress-strain models for confined concrete were considered to predict ultimate confined compressive stress and corresponding strain. Accuracy of existing models was assessed by mean of the ratio of analytical to experimental values and associated standard deviations. For ultimate stress predictions, the lowest mean value of the ratio of analytical to experimental ultimate compressive stress was 1.07 with a standard deviation of 0.10. However, none of the considered models was able to provide good estimates of ultimate strains.
Panuwat Joyklad, Nazam Ali, Ekkachai Yooprasertchai, Syed Taseer Abbas Jaffar, Hassan M. Magbool, Qudeer Hussain, and Krisada Chaiyasarn
Elsevier BV
Muhammad Asharib Shahid, Muhammad Usman Rashid, Nazam Ali, Krisada Chaiyasarn, Panuwat Joyklad, and Qudeer Hussain
MDPI AG
Reinforced concrete is used in the construction of bridges, buildings, retaining walls, roads, and other engineered structures. Due to seismic activities, a lot of structures develop seismic cracks. The rehabilitation of such structures is necessary for public safety. The overall aim of this research study was to produce a high-performance hybrid fiber-reinforced concrete (HPHFRC) with enhanced properties as compared to plain high-performance concrete and high-performance fiber-reinforced concrete (HPFRC) for the rehabilitation of bridges and buildings. Kevlar fibers (KF) and glass fibers (GF) with lengths of 35 mm and 25 mm, respectively, were added and hybridized to 1.5% by mass of cement to create hybrid fiber-reinforced concrete mixes. Eight mixes were cast in total. The compressive strength (f′c), flexural strength (fr), splitting tensile strength (fs), and other mechanical properties, i.e., energy absorption and toughness index values, were enhanced in HPHFRC as compared to CM and HPFRC. It was found that the concrete hybridized with 0.75% KF and 0.75% GF (HF-G 0.75 K 0.75) had the most enhanced overall mechanical properties, illustrating its potential to be utilized in the rehabilitation of bridges and structures.
Muhammad Ashraf Javid, Nazam Ali, Syed Arif Hussain Shah, and Muhammad Abdullah
Springer Science and Business Media LLC
Muhammad Ashraf Javid, Nazam Ali, Tiziana Campisi, Giovanni Tesoriere, and Krisada Chaiyasarn
MDPI AG
This paper aims to identify commuters’ perceptions towards the metro-bus service system considering various social constraints, mobility incentives and restrictions, and personal norms. A questionnaire survey was designed, which consisted of the personal information of respondents, travel properties, and preferences with the metro-bus system. This survey was conducted in Lahore city, and a total of 333 samples were obtained. The findings of the Structural Equation Modeling (SEM) revealed that the social constraints in traveling, public transport incentives, and specific parking restrictions have a significant influence on commuters’ moral obligations to reduce traffic congestion, mitigate environmental menaces, and protect natural resources. The ANOVA and SEM analysis showed that significant differences exist among low-, middle-, and high-income commuters in terms of their behavioral intentions towards the metro-bus service. These findings implicate that specific incentives on the use of public transport modes and parking restrictions are useful in changing the behavioral intentions of travelers towards transit modes such as the metro-bus service.