Mazdak Nik Bakht

Concordia University Montreal · Department of Building, Civil and Environmental Engineering

Automated fault detection and diagnosis (AFDD) in HVAC systems can provide significant energy savings as demonstrated in many previous studies. However, one of the main challenges facing AFDD field implementation is the lack of standardized data structures in most commercial buildings especially without any labeling of faulty data, which makes it c...

The building sector is a major player in the world’s contribution to climate change, partly due to its dependence on large quantities of materials. The circular economy model of material flow has been gaining attention in the past decade as it seeks to promote the use of construction, renovation, and demolition (CRD) waste as inputs for new buildin...

There are growing concerns for the remaining service life of concrete infrastructure under normal service conditions and the structural resilience under extreme climate events. Therefore, advanced and reliable computational tools are required for the assessment of existing structures’ condition, and the estimation of their serviceability. Tradition...

This paper introduces a methodology that combines a physics-based model with observed data for accurately modeling the deflection of an elastic beam in the context of structural health monitoring. The challenges associated with physics-based and databased methods such as computational time, simplifying assumptions, and seamless integration of senso...

Occupational exoskeletons (OEs) are wearable devices designed to assist and enable human motion for workers in industries ranging from manufacturing to construction. As with workers in other industries, the opportunity provided by OEs for construction workers is to reduce injury rates for the benefit of worker health and productivity. Potential ris...

Massive amounts of Construction, Renovation, and Demolition (CRD) waste are produced from the construction sector. The circularity of the construction is gaining momentum for controlling and reducing the stream and amount of CRD waste. To this end, the deconstruction concept, i.e., a planned disassembly of components and materials of the built faci...

Globally, the construction industry has underperformed in terms of managing budget overruns. In North America alone, about 70% of construction projects are late and over budget. Therefore, it is critical for budget planners to be fully aware of the most frequent patterns impacting the budget allocation at the project level. This will prevent neglec...

The efficiency and sustainability of bridge infrastructure asset management are highly dependent on the availability of accurate predictions for the structural condition of assets, which is essential for bridge safety. Much research has been done on this topic, and many researchers are exploring the power of machine learning techniques for this pur...

Construction contracts become more complicated along with the increasing design complexity, construction process and technology. The frequency of contractual disputes and dispute amounts are also growing. Modular and offsite construction (MOC) has been attracting a high level of attention as a solution to improve productivity, quality, and safety i...

Construction sites can be hazardous when workers perform their work in proximity of danger zones, which might lead to workplace fatalities. The majority of injuries and fatalities result from workers being struck by moving vehicles and entering danger zones. This paper presents a newly developed proximity detection system for estimating workers’ lo...

The building sector in New York City (NYC) accounts for about 75% of the greenhouse gas emissions (GHGE), and 40% of total energy consumption with an increasing rate of 5%. In a megacity like New York, tackling the lack of efficiency and sustainability in residential buildings requires identification, prediction, and analysis of energy performance...

The adoption of Building Performance Simulation for decision-making during the early phases of design would help improve the building's lifecycle performance. One important challenge, however, is that most building parameters are not yet finalized during such early phases, hence an extensive number of design scenarios will exist to be simulated. Gi...

Massive amounts of Construction, Renovation, and Demolition (CRD) waste are produced from the construction sector. Growing needs for the circularity of the construction call for controlling and reducing the stream and amount of CRD waste. To this end, the deconstruction concept has emerged as a more resource-friendly alternative compared to demolit...

The COVID-19 pandemic has impacted how the construction industry operates around the world. To fight the risk of transmission, new health, safety, and environmental (HSE) protocols have been put in place. Among these protocols are social distancing and limiting the number of workers per area, where social distancing acts as a so-called protective b...

Rapid pavement deterioration is a major problem in areas with harsh weather exposure and/or high truck traffic loading. While several studies in recent years have focused on pavement deterioration and management systems, there is not, to date, a robust method explaining how large amounts of pavement data can be processed to identify homogeneous gro...

Urban-scale energy simulation relies on the understanding of occupants’ presence in buildings and consequently in cities. Therefore, occupancy profiles (i.e., the relative number of occupants in a specific hour of the day) are usually used in the energy simulation on the city level. However, available occupancy standard profiles are incapable of co...

The National Pollutant Release Inventory (NPRI) was enacted in Canada as an information management tool under federal administration to assist in identifying the amount of point pollution sources. This study demonstrates an approach to combine on-ground air pollutant emission inventory (i.e., NPRI) with satellite monitoring data to verify the impac...

“Lessons for Contract Administration in Modular and Off-site Construction through Court Cases Analysis”

Accurate occupancy information can help in optimizing the operation of building systems. To obtain this information, previous studies suggested using WiFi connection counts due to their strong correlation with occupancy counts. However, validating this correlation and investigating its variation have remained limited due to challenges regarding the...

The automated fault detection and diagnostics (AFDD) of heating, ventilation, and air conditioning (HVAC) using data mining and machine learning models have recently received substantial attention from researchers and practitioners. Various models have been developed over the years for AFDD of complete HVAC or its sub-systems. However, HVAC complex...

Building performance simulation (BPS) applied at earlier stages of design has the potential to assist design parameter decisions that significantly impact a building’s life cycle. Since at such early stages, numerous design variables are still undetermined (e.g. window type, insulations, etc.) the scenarios to be simulated through BPS will be vast...

Construction renovation projects increase the risk of structural fire, mostly due to the accumulation of combustible construction materials and waste. In particular, when the building remains operational during such projects, the redistribution of occupants and interruptions with access corridors/exit egress can exponentially increase the risk for...

A construction contract is a mutually agreed upon and signed document by the contracting parties and plays a significant role in controlling and preventing disputes in a project. This paper's main objective is to develop a framework to assess sources of ambiguity in construction contracts for comprehensive referencing and early detection of potenti...

Several construction projects, worldwide, are suffering from delays and budget overruns; and Western Asia is not an exception. Studies have identified delays in progress payments and change order approvals as two of the main root causes of overruns in large building projects in the Middle East. In this study, the effect of procurement methods on th...

Contribution of citizens is a key factor in the success of urban development projects and the cornerstone of smart cities in general. The domain researchers have attempted to understand the attributes of a meaningful and effective collaboration with citizens and improve the quality of engagement accordingly. With this aim, a rich and extensive lite...

Adapting building systems' operation to occupancy variations can provide significant energy savings, but this is typically constrained by the unavailability of occupancy information. Although several technologies have been introduced to integrate real-time occupancy information in heating, ventilation and air-conditioning (HVAC) systems operations...

Due to severe climate change impact on electricity consumption, as well as new trends in smart grids (such as the use of renewable resources and the advent of prosumers and energy commons), medium-term and long-term electricity load forecasting has become a crucial need. Such forecasts are necessary to support the plans and decisions related to the...

Building Information Modeling (BIM) can store information of building elements and provide a computational platform for physical analyses for building systems. BIM can resolve several problems throughout various phases of design (as well as construction and operation). While use-cases such as daylight or energy analysis widely take advantage of thi...

As construction projects become more complex, making strategic decisions such as selecting the appropriate delivery method and the right type of contract becomes more convoluted. Several studies have realized that delays in progress payments and change orders during construction projects are among the main causes of overruns in megaprojects. Using...

Efforts are being made by researchers and practitioners to realize the true definition of BIM (Building Information Model/Modelling). With an emphasis on the information (than the geometry representation), spatial relations and contextual information derived from BIM can aid users to better understand spaces and assets in the building. Data-infused...

Workspace interferences and collisions occurring on construction jobsites are products of unexpected spatiotemporal overlaps of resources. They affect the project performance and can create an unsafe environment. Current practices for workspace planning adopt a linear/mechanistic approach in modeling, which ignores uncertainties occurring during co...

Building Information Modelling (BIM) is defined as the process of creation and management of digital replica for building products in a collaborative design set-up. On this basis, BIM as a digital collaboration platform in AECO (Architecture, Engineering, Construction, and Operation) industry, can be upgraded to assist monitoring, control and impro...

Building energy simulation is traditionally applied at late phases of the design, when most decisions on specifications of building systems are made. There has been a growing attempt in the literature to enable such simulations at earlier phases of design, when decisions’ impact on the lifecycle behavior is the strongest. While researchers have dev...

The energy consumption of buildings depends on numerous factors that can be categorized in four major categories: geometry parameters; location; attributes of electric and mechanical systems; and behaviour of users. Most of the existing publications on ‘energy-consumption influencing parameters’ test the sensitivity of energy consumption to these i...

Economic analysis has been known as one of the major challenges for energy consultants in early phases of design, when project characteristics are not clear enough. One source of the challenge is to obtain cost data for elements based on their energy performance (rather than the product information). Therefore, quantitative economic analyses are us...

Building Information Modelling (BIM) corresponds to generation and management of the digital representa-tion of the building products (and processes) by containing building elements in a unique source file. Open BIM, relying on the platform-independent standard Ifc (Industry Foundation Classes), created by Buid-lingSMART, is supposed to increase th...

Successful adoption and management of sustainable urban systems hinges on the community embracing these systems. Capturing citizens’ ideas, views, and assessments of the built environment will be essential to this goal. In collaborative city planning, these are qualified and valued forms of partial knowledge that should be collectively used to shap...

Geometric and non-geometric data from Building Information Models (BIM) need to be manually reconstructed in acoustic simulation software to examine building acoustic performance. This process is time-consuming, error-prone, and the accuracy of acoustic analysis results will depend on the expertise of the user. The process is also unidirectional (i...

Modular coordination in building construction has become increasingly popular, particularly in Northern Europe and North America. Modular construction in Canada gained considerable attention over the last decade due to its positive impact on project constraints, safety, and preventing construction and demolition waste. However, the modular construc...

Spatial temporal clashes happen when workspaces overlap to share the same location at the same time period. The impacts of such overlap, as stated by the literature could extend from loss of productivity to property damage or death. The determination of the magnitude of the clash is based upon many parameters such workspace type and activity critic...

Traditional energy efficiency certificates for buildings, such as LEED (Leadership in Energy and Environmental Design), in spite of their worldwide success, have not yet gained the expected penetration in some developing (and less-developed) countries. Some factors contributing to such a trend include cost, complexity, and demand for new resources...

The internet of things (IoT) is considered one of the fastest-growing topics attracting the attention of the technological world. Building internet of things (BIoT) focusses on the IP-marked components of a building, connected to the network (internet), generating and collecting data, or executing orders autonomously and sim-autonomously. BIoT enco...

A project discussion network is a space where project stakeholders form relationships among each other and share information about the project. Virtual discussion networks may refer to networks of e-mails, document exchange and social media (such as Twitter, Facebook, YouTube, etc.). As such, both social linkages and semantics of the exchanged cont...

Using content analysis, an approach is presented to help extract topics of interest to local community during project planning. This is helpful for fine-tuning and customizing the language used in communication with the public. Hopefully, reducing communication mismatches can help support constructive dialogue that is not “lost in translation”. The...

One key role of urban informatics is to understand demands, challenges, and opportunities for major infrastructure projects in a bottom-up format. In this respect, engaging citizens through communication tools available in Social Web, and distilling micro-knowledge distributed among them appear to be reliable and promising streams. Chaotic nature a...

The volume presents, in a synergistic manner, significant theoretical and practical contributions in the area of social media reputation and authorship measurement, visualization, and modeling. The book justifies and proposes contributions to a future agenda for understanding the requirements for making social media authorship more transparent. Bui...

The process of public consultation for planning and construction of sustainable urban infrastructure requires a bidirectional communication among as many stakeholders of the project as possible. In modern infrastructure projects, social web and online social media play an important role in involving citizens through what is referred to as “micropar...

Decision making has always been a major topic of research in the field of construction engineering and management. Recent trends (such as the push for sustainability, the increased desire for public engagement, and the globalization in construction) have influenced the environment under which decision makers work. Consequently, the models of how de...

Several studies have emphasized the role of social media in public involvement during planning, construction, and operation of infrastructure. Social media can offer optimal, bidirectional communication with the public and an efficient flow of information and feedback between decision makers and project end users. However, the underlying social net...

A variety of communication channels and outreach tools are in use by Public Involvement (PI) programs in transportation planning and construction. Several metrics and measures are traditionally used to evaluate the performance of such programs and to measure their level of success in achieving their pre-defined goals. These metrics are mainly quant...

Evolution of civil infrastructure from a technical artifact into an engineering system and a national asset over the past century has created a new discourse for development, construction, and management of infrastructure, which more and more emphasizes soft and subjective aspects of the system. Modern civil infrastructure is a complex system compo...

Purpose – The purpose of this paper is to present a socio-technical approach to modeling the behavior of roadway users, asset managers, and politicians toward roadway performance and asset management. This approach models the complex interactions that occur between these agents in a complex system. Most modeling approaches in the domain of infrastr...

This paper presents a summary of the tools that can be used to analyze public discussion over social media regarding infrastructure projects. It uses the cross-town transit project in Toronto as a case to illustrate how social network analysis can help decision makers to understand the composition and general trends of local community opinion. It f...

In this paper, a modified group theoretic method is introduced for symmetry analysis of regular structures. A structure is called regular if its model can be formed by one of the graph products. Here, the concepts from graph products are used in order to simplify the conventional group theoretic analysis of cyclically symmetric structures. The anal...

In this paper graph products are utilized for the free vibration analysis of regular structures. A structure is called regular if its model is a product graph. Here, matrices involved in dynamic equilibrium are decomposed into the submatrices of lower dimensions, and in certain cases these are completely digonalized and the natural frequencies are...

In this paper, a new combined graph-group method is proposed for eigensolution of special graphs. Symmetric regular graphs are the subject of this study. Many structural models can be viewed as the product of two or three simple graphs. Such models are called regular, and usually have symmetric configurations. The proposed method of this paper perf...

Group-theoretical methods for decomposition of eigenvalue problems of skeletal structures with symmetry employ the symmetry group of the structures and block-diagonalize their matrices. In some special cases, such decompositions can further be continued. This particularly happens when submatrices resulted from the decomposition process, correspond...

The main objective of this article is to develop a methodology for the efficient calculation of buckling loads for frame structures having high-order symmetry properties in order to reduce the size of their associated eigenvalue problems. This is achieved by decomposing the second-order stiffness matrix of a symmetric model into submatrices using a...

In this paper, after a brief review on basic concepts of group theory and properties of the symmetry groups, different products which are defined in graph theory are introduced. Kronecker product of the matrices and direct product of the groups are then defined and the inter-relation between the graph products and the direct product of the groups i...

In this article, group theory is employed for block diagonalization of Laplacian matrices of symmetric graphs. The inter-relation between group diagonalization methods and algebraic-graph methods developed in recent years are established. Efficient methods are presented for calculating the eigenvalues and eigenvectors of matrices having canonical p...

The main objective of this article is to develop a methodology for an efficient calculation of buckling loads for symmetric frame structures in order to reduce the size of the eigensolution problems involved. This is achieved by decomposing a symmetric model into two submodels followed by their healing to obtain the factors of the model. The buckli...

The main objective of this article is to develop a methodology for an efficient calculation of the eigenvalues for symmetric mass–spring systems in order to reduce the size of the eigenproblem involved. This is achieved using group-theoretical method, whereby the model of a symmetric mass–spring system is decomposed into appropriate submodels. The...