Introduction:

The construction industry is a significant contributor to global environmental challenges, accounting for approximately 20–40% of global energy consumption and a considerable proportion of carbon emissions [1, 2]. In Singapore, the construction sector alone contributes 16% of the nation’s total energy use, with energy expenses forming 20–40% of a building's operational costs [3]. Given these figures, it is imperative to adopt sustainable construction practices that mitigate environmental impacts while promoting energy efficiency and sustainability.

In response to mounting environmental concerns, sustainable construction practices have gained global prominence as industries seek to minimize their ecological footprints [4]. These practices include the use of eco-friendly materials, energy-efficient building designs, waste reduction techniques, and the implementation of renewable energy sources. However, transitioning to sustainable practices in construction, particularly green building projects, presents unique challenges. These challenges include higher upfront costs, technical complexities associated with new technologies and materials, and the need for specialized project management approaches [5, 6].
The Building and Construction Authority (BCA) in Singapore has introduced initiatives such as the Green Mark Scheme to encourage environmentally friendly construction. This scheme sets standards for green building designs, construction practices, and operational efficiency, with a target of achieving 80% Green Mark certification across Singapore’s buildings by 2030 [7]. Despite these efforts, the lack of a structured project management framework for green projects continues to hinder widespread adoption. Effective project management is critical in ensuring that green construction projects meet their sustainability goals while staying within budget and on schedule.
This study addresses the gap by examining the unique challenges of green construction projects, comparing them with conventional projects, and proposing solutions to overcome these barriers. It explores how integrated communication strategies, stakeholder engagement, and lifecycle-based planning can mitigate common issues such as cost overruns and technical complexities. By developing a detailed project management framework, this research aims to provide project managers and stakeholders with the tools and knowledge needed to implement effective sustainable practices in the construction sector.
The methodology involves a systematic review of existing literature to identify key factors that influence the success of green construction projects. Additionally, empirical data is collected through surveys with industry experts to gain insights into the practical challenges and solutions experienced in the field. This dual approach ensures that the proposed framework is both theoretically sound and practically applicable.
The findings of this study highlight the importance of structured frameworks for advancing sustainable practices in the construction sector, particularly in rapidly urbanizing contexts like Singapore. By addressing the specific needs and challenges of green projects, this research contributes to the development of best practices that can be adopted by construction firms worldwide. Ultimately, the successful implementation of sustainable project management frameworks can lead to significant environmental, economic, and social benefits, driving the construction industry towards a more sustainable future.
In conclusion, the integration of sustainable project management frameworks is essential for the successful implementation of green construction projects. This study provides valuable insights into the challenges and solutions associated with green building initiatives, offering a comprehensive framework that can guide project managers and stakeholders in achieving their sustainability goals. By fostering a collaborative and informed approach to project management, the construction industry can make significant strides towards reducing its environmental impact and promoting sustainable development.

2. Literature Review:

Sustainable construction emphasizes minimizing environmental impacts throughout a building's lifecycle, from design to demolition. This holistic approach ensures that buildings are constructed, operated, maintained, and eventually dismantled in ways that reduce their environmental footprint [8]. According to Kibert, sustainable construction integrates ecological, social, and economic considerations to ensure long-term sustainability. This integration involves using resources efficiently, minimizing waste, and considering the broader social and economic impacts of construction activities [9]. Green building projects, as a subset of sustainable construction, introduce unique complexities such as material selection, waste management, and energy efficiency optimization. These complexities arise because green buildings aim to go beyond the minimum environmental standards and incorporate advanced sustainability features [10].

Studies by Glavinich and Yudelson highlight the differences between green and conventional construction. Traditional projects primarily prioritize cost and time efficiency, aiming to complete projects within budget and schedule constraints. In contrast, green projects require holistic, integrated design approaches and advanced communication strategies to align diverse stakeholders. These projects involve multiple disciplines working together from the early stages to ensure that sustainability goals are met. This collaborative approach often requires more time and resources in the planning phase [11, 12]. Zhang et al. emphasize that incorporating sustainable materials and technologies increases project costs by 3–25%, posing significant financial barriers. The higher costs are often due to the premium prices of eco-friendly materials and the need for specialized construction techniques [13].

Technical challenges also persist, as green technologies often demand specialized expertise and untested methodologies. Implementing new technologies can be risky because their performance may not be well-documented, and construction teams may lack experience with their application [14]. Eisenberg et al. identify insufficient knowledge and unfamiliarity with green practices as critical impediments, further compounded by protracted regulatory approval processes. The regulatory environment can be a significant hurdle, as green projects may need to comply with additional standards and obtain more permits than conventional projects [15]. Additionally, studies by Hwang and Tan reveal that inadequate stakeholder communication and a lack of client interest exacerbate these challenges, necessitating comprehensive frameworks for green project management. Effective communication is crucial for ensuring all stakeholders understand and support the sustainability objectives, while client interest drives the demand for green projects [16].

3. Methodology:

3.1 Data Collection:

To address the research objectives, this study employed a mixed-methods approach, combining a literature review with survey-based data collection. This approach allowed for a comprehensive analysis that integrates both quantitative and qualitative data. The survey targeted 101 Green Mark Professionals (GMPs) and Green Mark Managers (GMMs) in Singapore, capturing responses from 31 participants. These professionals were chosen due to their expertise and experience in managing green building projects. The questionnaire included sections on demographic information, challenges faced in green construction, and proposed solutions. The demographic section collected data on the respondents' roles, experience levels, and the types of projects they manage. The sections on challenges and solutions sought to identify common issues and gather expert opinions on effective strategies [17].

The survey responses were analyzed using advanced statistical techniques to ensure rigorous data interpretation. Techniques included one-sample t-tests to compare the mean responses against a known value, ANOVA (Analysis of Variance) to determine differences between groups, and Post-Hoc tests to conduct multiple comparisons while controlling for Type I errors. These statistical methods allowed for the identification of significant challenges and their impacts on project outcomes [18]. Additionally, qualitative insights from open-ended responses were integrated to provide context and depth to the findings. This qualitative data was analyzed using thematic analysis, identifying patterns and themes that offered deeper insights into the challenges and proposed solutions. By combining these methods, the study ensured a robust and comprehensive analysis of the data, leading to actionable conclusions and recommendations [19].

In conclusion, this expanded and detailed methodology provides a thorough framework for analyzing the impact of sustainable project management frameworks on green construction projects. By leveraging both quantitative and qualitative data, the study offers a well-rounded perspective on the challenges and potential solutions for implementing sustainable practices in the construction industry.

4. Results:

4.1 Identified Challenges:

The survey identified five critical challenges in green construction. The first challenge is increased project costs. Respondents identified the higher cost of green materials and technologies as the most significant issue, with cost premiums ranging from 3% to 25% [17]. This increase in costs is often due to the higher prices of environmentally-friendly materials and the additional expenses associated with sustainable construction practices. These costs can be a significant barrier for stakeholders who are more accustomed to conventional building materials and methods.
The second challenge is communication gaps. Miscommunication among stakeholders often led to delays and inefficiencies, which were attributed to the technical complexity of green practices [18]. Effective communication is crucial in green construction projects as they involve numerous stakeholders, including architects, engineers, contractors, and clients, each with their own specific requirements and expectations. The technical jargon and the complexity of sustainable practices can often lead to misunderstandings and misalignments in project goals.

The third challenge is limited client interest. A lack of awareness regarding the long-term benefits of green buildings discouraged investment in sustainable projects [19]. Many clients prioritize initial costs over long-term savings and environmental benefits, which can make it challenging to secure funding for green projects. Educating clients on the benefits of sustainable construction, such as lower operational costs, improved building performance, and positive environmental impact, is essential to increase interest and investment.
The fourth challenge is regulatory delays. Approval processes for green technologies and materials were identified as lengthy and inconsistent, further deterring adoption [20]. Regulatory bodies may not be fully equipped to handle the innovative aspects of green technologies, leading to prolonged approval times and uncertainties in the adoption process. Streamlining these processes and providing clear guidelines can help in reducing delays and fostering the adoption of green technologies.
The fifth challenge is technical knowledge deficits. Stakeholders often lacked the expertise required to implement and manage green technologies effectively [21]. This knowledge gap can lead to improper implementation of green technologies, reducing their effectiveness and potentially leading to project failures. Providing specialized training and education programs for stakeholders can help in bridging this knowledge gap and ensuring the successful application of sustainable practices.
The impacts of these challenges were quantitatively analyzed. The results revealed that these challenges significantly affected project budgets, with a mean score of 4.1, indicating a high impact. Project schedules were also impacted, with a mean score of 3.32, highlighting delays and time overruns. The quality of the projects was moderately affected, with a mean score of 3.16. ANOVA results confirmed the statistical significance of these impacts (p < 0.05) [22].

5. Discussion:
The findings underscore the necessity of tailored project management frameworks for green construction. By integrating lifecycle-based planning and enhanced communication protocols, project managers can mitigate cost and technical barriers. For instance, early stakeholder engagement and cross-disciplinary training programs can address knowledge deficits, while government subsidies can alleviate cost concerns [23]. Lifecycle-based planning involves considering the environmental impact of a building throughout its entire life, from design and construction to operation and demolition, ensuring that sustainable practices are maintained at each stage.
Moreover, adopting digital tools such as Building Information Modeling (BIM) facilitates real-time collaboration, improving communication and decision-making [24]. BIM allows project stakeholders to visualize and manage project data in a collaborative digital environment, reducing miscommunication and enhancing project efficiency. The study also highlights the importance of regulatory reforms to streamline approval processes for green technologies, as proposed by Eisenberg et al. [25]. Regulatory reforms can provide clearer guidelines and faster approval processes, encouraging the adoption of sustainable practices in the construction industry.

6. Conclusion:
In conclusion, this study provides a comprehensive analysis of the challenges and solutions associated with green construction projects in Singapore. By addressing financial, technical, and communication barriers, the proposed framework offers a pathway for more effective project management. Future research should focus on validating this framework across diverse contexts and exploring the integration of advanced technologies such as artificial intelligence in sustainable construction practices. Artificial intelligence can offer predictive analytics, optimize resource use, and enhance project management processes, making sustainable construction more efficient and effective.