Schedule contingency analysis for transit projects using a simulation approach

This paper presents a probabilistic method to establish schedule contingency levels based on percent completion of the project. The objective is providing a distribution for contingency for various percent completion levels which allows the project owner/manager to choose the schedule contingency at their comfort level. The proposed method is applied on real data from a number of US transit projects and actual schedule overruns for different phases of the project development (preliminary engineering, final design and construction) are analyzed. These values are used to establish the required contingency at the conclusion of each of the mentioned project phases. Additionally, using these values, the required contingency at various points during the construction phase (such as 25% and 50% completion) is calculated and reported. This approach can be used by project owners to plan realistic schedules during various phases of the project, providing better control on duration and the opportunity for being prepared to take necessary action in case the available schedule contingency falls below reasonable levels

Assessment of Energy Credits in LEED-Certified Buildings Based on Certification Levels and Project Ownership

Compared to other categories, the Energy and Atmosphere category contributes the most to the maximum obtainable points in the Leadership in Energy and Environmental Design (LEED) certification system. The objective of the study was to identify the extent to which project teams take advantage of the credits in the Energy and Atmosphere category of LEED. This study analyzes the performance of practitioners in achieving points in the Energy and Atmosphere credits of LEED-New Construction (NC) 2009 for 1500 buildings that received LEED certification in the US. For a better understanding of the credit patterns, the differences in the performance of practitioners are investigated relative to certification levels and project ownership. Achievement in credits is calculated in terms of percent of maximum points (PMP), since the maximum achievable points differ for each credit. Practitioners’ achievements in the credits were ranked as follows: (1) enhanced commissioning, (2) optimized energy performance, (3) enhanced refrigerant management, (4) green power, (5) measurement and verification, and (6) on-site renewable energy. The largest achievement differences were observed in the on-site renewable energy credit. Concerning building ownership, investors were found to optimize mostly energy efficiency and on-site renewable energy, but to mostly skip enhanced refrigerant management. Performance in the measurement and verification credit was similar for all owner types, whereas investors performed differently from corporations, and government agencies in the enhanced commissioning credit. Practitioners who recognize these priorities and differences are expected to be better positioned to make sustainability-related decisions in building design and construction

Exploring the Barriers against Using Cryptocurrencies in Managing Construction Supply Chain Processes

Various stakeholders are involved in managing supply chain processes in construction. Suppliers can hardly tolerate upfront costs when faced with flaws in the payment pipeline. This is a serious problem in building construction that uses a large variety of materials as opposed to civil construction that requires fewer types of materials. Alternative secure payment systems are needed, and the use of cryptocurrencies can be an option. However, cryptocurrencies are seldom used in building construction projects due to several challenges that are mostly ignored in the existing literature. To fill this gap, this study investigates the use of cryptocurrencies in construction supply chains as an alternative payment solution to improve the financial performance of the stakeholders by taking advantage of this economical and traceable financial transaction system. The study involves exploratory, descriptive, and empirical survey research. Accordingly, a literature review, focus group discussions, and statistical analyses (Friedman test, Wilcoxon test, and Mann–Whitney U test) were performed. The results imply that a lack of technical knowledge about cryptocurrencies, fluctuations in the value of cryptocurrencies, limited market opportunities, security gaps, personal information required by cryptocurrency systems, no assurance of permanent use, and government actions limiting the use of cryptocurrencies were the most significant barriers against using cryptocurrencies in construction supply chain management. The findings are expected to provide critical information to construction professionals and regulatory agencies about the potential advantages and shortcomings of cryptocurrencies, hence motivating policymakers to create strategies that minimize the concerns of construction professionals about using cryptocurrencies in the building construction industry

Challenges in the Integration of E-Procurement Procedures into Construction Supply Chains

The growing interest in digitalization signals a need for technology-oriented supply chain operations in the construction industry. Electronic procurement (e-procurement) aims to convert traditional procurement approaches into web-based/online platforms. Even though e-procurement is an effective tool that may improve supply chain management, the extent of e-procurement implementation has been slow to date. This study investigates the barriers that hinder e-procurement implementation in construction supply chains with the aim of prioritizing solutions to the identified barriers relative to time, cost, quality, and construction owner satisfaction. A comprehensive literature survey was performed, and a focus group discussion was organized for the purpose of the study, which resulted in the identification of 28 barriers. Then, a total of 131 construction practitioners were contacted to evaluate the barriers through a questionnaire survey. The responses were analyzed using the fuzzy Technique for Order Preference by Similarities to Ideal Solution (fuzzy TOPSIS) for prioritization. Finally, 15 semi-structured interviews were conducted to gain a deeper insight into the transformation process from the conventional procurement route to the e-procurement solution. Findings highlight that issues related to unexpected order cancellations, large variations in material costs, and the uncertain nature of the industry that requires a large number of changes are ranked as the most significant barriers. Given the highly competitive environment and the high demand for advanced technologies in the construction industry, a new paradigm can enhance the efficiency of supply chain operations. Exploring and eliminating the potential difficulties of adopting e-procurement in the procurement process may be a good start. Overall, this research is expected to facilitate the transformation of the procurement process by addressing the critical barriers identified by practitioners

More than just a green facade: Vertical gardens for sound absorption and architectural acoustics

Noise can become uncomfortable for us in many situations both indoors and outdoors. External noise consists of activities (airplanes flying overhead, traffic on the road, etc.) that are either loud enough to be considered uncomfortable when outdoors, or are of an elevated volume to the extent that they infiltrate buildings at levels considered uncomfortable. In the case of internal uncomfortable noise, this can either stem from noisy activities that occur inside the building (people speaking loudly, printers, etc.), or when an unexpected sound suddenly permeates an area that has a very low level of background noise. The most common manner by which to mitigate excess noise is through the use of certain materials, which either insulate against noise passing through the material, or absorb the noise wavelengths. In the case of the latter, vertical gardens present themselves as not only an aesthetic element in architecture, but also as a potential acoustic control tool in building design. For this work 10 m2 of vertical garden substrate modules was tested in a full size reverberation chamber. The objective was to open the doors for vertical gardens to be used in architectural acoustic design