Authors: Shiva Pooladvand, Hosein Taghaddos, Arash Eslami, Ala Nekouvaght Tak, Ulrich (Rick) Hermann

Abstract:

Cranes are one of the most critical and expensive pieces of construction industry equipment requiring intense safety considerations. Lifting crews should attempt to develop an effective lift plan to improve the operation’s safety and reduce the risks of potential accidents. Although various systems are developed to enhance lifting operations’ safety, most cannot evaluate the entire lifting process in an interactive visual environment. This paper contributes to the body of knowledge by presenting a crane simulator system developed in the virtual reality (VR) environment integrated with a database of comprehensive lift studies and a detailed crane path planning system. This interactive system evaluates the lift operation quantitatively in real time in terms of its safety and practicability for the entire operation (entire lift path). The developed system can be employed in practice by crane operators and lift engineers for various objectives, including gaining hands-on experience before the actual operation, enhancing engineered lift planning, increasing workplace awareness, and evaluating and mitigating lift-related risks. The proposed framework is validated through two scenarios in a modular construction project in Alberta, Canada.

Authors: Ali Mansouri , Hosein Taghaddos , Ala Nekouvaght Tak , Amir Sadatnya , Kamyab Aghajamali

Abstract:

Large-scale earthmoving operations, common in mining excavation, contribute significantly to Greenhouse Gas (GHG) emissions. This paper introduces a simulation-based system aimed at quantifying these emissions and identifying practical and achievable steps for reducing them. The system we developed considers site-specific factors, including equipment specifications, topography, route, and weather conditions. Notably, it enables ‘what-if’ scenario analyses, allowing us to evaluate the impact of different parameters on emissions. The system’s unique feature is the optimal allocation of resources through an intelligent decision-making system, which reduced GHG emissions by approximately 7.6% in the case study. Turning off equipment during idle periods further decreases emissions by up to 11.3%. These findings highlight the potential of operational adjustments in mitigating the environmental impact of earthmoving projects.

Authors: Mohammadreza Kalantari , Hosein Taghaddos , Mohammadhossein Heydari 

Abstract:

Inefficient procurement processes can lead to increased costs and project delays. Addressing information management inefficiencies is a significant but largely unexplored area within construction procurement strategies, despite potential for automation through Database Management Systems (DBMS) and Industry Foundation Classes (IFC). Subjective approaches constrain procurement planning, hindering optimal solutions. This paper addresses the gap by developing a comprehensive semi-automated procurement planning framework. The framework offers flexibility through a two-phased optimization employing Particle Swarm Optimization (PSO) or Genetic Algorithm (GA), integrated with a Building Information Modeling (BIM)-driven database platform compatible with various modeling software. It enhances decision-making by considering indirect costs and allowing installment payments while generating a 4D schedule for improved supply chain stakeholder visualization and decision-making (e.g., project managers), demonstrating improvements over traditional procurement plans in a real-world case study. The developed framework enables future research on integrating real-time data, predictive analytics, and smart contracts to further enhance procurement management.

Authors: Maedeh Taghaddos , Ali Mousaei , Hosein Taghaddos , Ulrich Hermann (Rick) , Yasser Mohamed , Simaan AbouRizk 

Abstract:

Efficient scheduling and resource allocation for large-scale industrial projects is challenging due to their size and complexity, especially with fast-track contracts, which often lack detailed information during the early planning phase. This paper introduces a data-driven workface planning framework to enhance scheduling and resource allocation while accommodating uncertainties and constraints (e.g., minimum and maximum resource allocation curves, dynamic predecessor relationships, congestion limits). This framework employs an integrated approach, combining time-stepped simulation with graph-based optimization. By leveraging historical data and expert knowledge, the data-driven framework mitigates certain subjective assumptions, including durations and resource allocations. In practical application, the framework generates near-optimal schedules, even with limited information. Applying the framework to a fast-track industrial construction project case study demonstrated enhanced resource allocation. These findings offer practical benefits to industrial projects regarding time and cost savings and serve as a foundation for future research in data-driven project planning approaches.

Authors: Soroush Sobhkhiz, Hossein Taghaddos, Mojtaba Rezvani, Amir Mohammad Ramezanianpour

Abstract:

Currently, designers require to use numerous incomplete data sources and make multiple assumptions to conduct an LCA. We argue that traditional methods are incapable of addressing LCA data requirements, and for such a data and meta-data intensive task, the semantic web is the only logical choice of technology. This paper presents a review of the semantic web and its applications in the construction industry, along with an overview of the current LCA tools. LCA challenges are thoroughly discussed, and a framework using the semantic web is developed to address the data management issues of BIM-LCA applications. For comparison, the implementation is also done using an LCA tool (Tally), and a method using Relational Database Management Systems (RDBMS). Results show that the proposed method is superior to RDBMS methods in terms of capturing semantics and can improve LCA tools by providing reliable data in the early design stages.

Authors: Ala Nekouvaght Tak, Hosein Taghaddos, Ali Mousaei, Anahita Bolourani, Ulrich Hermann

Abstract:

Heavy industrial construction, particularly when modularization is adopted, requires thorough heavy-lift studies to manage the extensive use of mobile cranes in congested and dynamic site layouts. This study introduces an integrated 4D crane simulation and onsite operation management framework for multiple concurrent mobile crane operations in the BIM environment with the support of a comprehensive database. Unlike similar recent efforts, the proposed framework is built upon previously developed crane planning and optimization systems, which enables generating accurate operation plans both in micro (objects) and macro scales (site). This framework addresses five different components regarding onsite crane operation management, including BIM-based multi-crane lift animation, scheduling and cost analyses, motion controlling in the BIM environment, safety monitoring and clash detection, and spatiotemporal site analyses. The developed framework’s functionality is validated by implementing it into a portion of a real project in Alberta, Canada, through three different cases.

Authors: Navid Kayhani, Hosein Taghaddos, Ali Mousaei, Saeed Behzadipour, Ulrich Hermann

Abstract:

Lift path planning is a significant subtask in constructability analysis, sequencing, and scheduling of congested industrial modular projects, impacting project cost, and safety. Although intuitive lift planning is still prevalent among the practitioners, this manual process might be tedious and error-prone for hundreds of lifts. This research presents an automated lift path planning method for heavy crawler cranes in no-walk scenarios employing a robotics approach. This method treats the lifted object as a three-degree-of-freedom convex mobile robot with discretized rotational and continuous translational motions. The proposed resolution-complete method models the crane capacity chart, tail-swing, and boom clearances as pseudo-obstacles in the lifted object’s configuration space. By reducing the lift path planning to a graph search problem, if any, the shortest path for the planar motion of the heavy-lift, along with its optimal pick-point, is identified. The developed heavy-lift path planning method is validated via two practical case studies.

Authors: S. Marzieh Bagheri, Hosein Taghaddos, Ali Mousaei, Farid Shahnavaz, Ulrich Hermann

Abstract:

Nowadays, the use of heavy mobile cranes in on-site construction of industrial projects has become inevitable. Due to the high rental cost of such cranes, an optimized plan is essential for the multiple crane lifts. This plan reduces the operating costs of the crane by minimizing waste time and lessens the potential of failures and accidents. However, developing an efficient lift plan can be challenging and time-consuming, considering the large number of lift options. This article presents a novel framework based on an informed search algorithm called A-star, which provides a semi-optimum lift plan based on a predetermined lifting sequence. This system talks to a comprehensive database to provide initial data. The proposed framework is applied successfully and validated in an actual modular construction project in Alberta, Canada. The results show a significant reduction in the total cost compared with the previously used lift planning algorithm.

Authors: Maedeh Taghaddos, Hosein Taghaddos, Ulrich Hermann (Rick), Yasser Mohamed, Simaan AbouRizk

Abstract:

Scheduling heavy industrial projects is challenging due to their size and complexity. Three-dimensional space and its discipline-specific tasks are an important asset in congested industrial sites, yet are not easily scheduled early in planning when detailed information is lacking. Although recent approaches have focused on enhancing space and crew management, effective scheduling of large-scale industrial projects with several interdependent constraints remains difficult. A comprehensive, hybrid planning framework capable of developing an efficient, high-level schedule accounting for uncertainties in bidding and execution is proposed. The framework employs simulation and optimization tools to determine best durations/modes in multi-mode activity networks and uses dynamic data adoption to continuously plan during project progression. The proposed framework uses historical information and expert opinion to automatically create a near-optimized schedule while considering various uncertainties. The proposed approach is tested and demonstrated with an illustrative example and an actual case study of industrial construction in Alberta, Canada.

Authors: Farid Shahnavaz, Hosein Taghaddos, Reza Sadeghi Najafabadi, Ulrich Hermann

Abstract:

Developing heavy-lift studies is a vital task in heavy congested industrial projects such as modular projects where it is necessary to lift modules with mobile cranes. However, preparing these lift studies can be time-consuming. Hence, automating this process is a great step in saving time, and reducing the percentage of errors, having the practitioner focus on lift planning rather than tedious tasks. A significant step in the pre-construction and construction phase of an industrial project is creating the 4D animation of lift processes. Such an animation develops a better understanding of the process and streamlines finding the best path for the mobile crane movements to avoid collisions. Such a 4D lift animation (i.e., simulation) can be a mandate when the lifting process is performed in a congested construction site involving more than one crane. This research study aims to propose a comprehensive framework for creating the 4D animation of a multi mobile crane lift process. The proposed approach can connect to a comprehensive model, in Building Information Modeling (BIM) terminologies, or can auto-generate the simplified CAD model containing the lifting objects (i.e., modules in modular construction) and obstructions by interacting with a central database. It can also auto-generate the 3D model of cranes in the set and pick positions. Then, the lift animation can be developed quickly in an automated manner by employing a customized Application Programming Interface (API). The developed API generates the lift animation of the cranes based on the defined timeline and lifting path by reading the required data (e.g., site information, modules information, cranes information, object models, and lift sequences) from the database. The proposed framework is validated by applying in a portion of a real modular industrial project in Alberta, Canada. The results show that the developed system has enough flexibility to simulate multi-mobile crane movements with various types of mobile cranes, multiple kinds of movements, and various site conditions.

Authors: Ala Nekouvaght Tak, Hosein Taghaddos, Ali Mousaei, Ulrich (Rick) Hermann

Abstract:

Modularization is becoming more popular in industrial construction to enhance various project management aspects, including time, cost, safety, quality, and productivity. Although many studies have highlighted the differences between modular and conventional (stick-built) construction, little research is conducted to evaluate alternative fabrication strategies (e.g., overseas versus local fabrication). Some practitioners prefer to build modules locally, while some others prefer to outsource the module fabrication overseas and ship them to the industrial plant. This dramatically affects the decision on the size of the module envelope, and in turn, many other associated factors. The purpose of this study is to develop an integrated framework to evaluate different module fabrication strategies. This study employs various automation tools (e.g., building information modeling (BIM), simulation modeling) to quantify the impact of module fabrication strategies on any selected industrial project. The proposed framework considers various project aspects such as shipment and handling, fabrication, lifting, module resizing, and module assembly yard to find the best fabrication strategy. An actual case study, part of an industrial plant in Alberta, Canada, is presented in this paper to elucidate research contributions.

Authors: S. Marzieh Bagheri , Hosein Taghaddos , Ulrich Hermann

Abstract:

Crawler cranes are the most pivotal components on large-scale modular construction sites. Generating a practical and safe lift plan significantly impacts the successful delivery of such projects. This paper introduces an integrated crane planning and lift scheduling framework for managing multiple concurrent mobile cranes’ operations. The presented framework is built upon recently developed crane planning and optimization systems. It aims to balance four primary areas of project management (time, cost, quality, and safety) through schedule enhancement, cost estimation, and risk mitigation. This approach leads to a more practical lift plan. Automating the process of detecting logical issues and satisfying the constraints in the lift planning process helps to improve time efficiency and reduce errors. This paper also scrutinizes crane operations to provide a realistic budget and schedule. The developed lift planning system is flexible and practical, as validated by its successful implementation in several real modular projects in North America.

Authors: Vahid Zamani, Ehsan Yavari, Hosein Taghaddos

Abstract:

Over the past two decades, Discrete Event Simulation (DES) has significantly influenced Construction Engineering and Management (CEM), leading to the development of sophisticated analytical frameworks. This study analyzes the application and impact of DES in CEM through scientometric, bibliometric, and qualitative analyses of 198 journal articles from the Web of Science database, spanning 2000 to 2023. Employing advanced graph-based and clustering techniques, we uncover patterns of scientific collaboration, co-citation networks, key contributing institutions, influential journals, and the evolution of research themes. Our findings spotlight major research avenues, including lean construction, building information modeling, project planning and control, hybrid simulation, and decision support systems. Anticipating future trends, we predict the integration of DES with emerging technologies such as digital twins, data analytics, cloud computing, and context-aware decision support systems. This study maps the current landscape and forecasts the trajectory of DES’s role in advancing CEM towards more integrated, technologically enriched methodologies.

Authors: Vahid Zamani, Hosein Taghaddos, Yaghob Gholipour

Abstract:

Discrete Event Simulation (DES) is an effective method to study cyclic and uncertain projects at the operation level. However, qualified DES results highly depend on the input data quality. This paper describes a simulation-enabled context-aware Decision Support System (DSS) based on sensor fusion to model earthwork operations realistically. The DSS backbone is a DES continually updated using real-time data. The information on earthmoving operations is exchanged between reality and DES using GPS and equipment-mounted cameras. The equipment spatiotemporal data and shovel-mounted cameras enhance the DES quality (i.e., locational and contextual awareness) by providing timely information about task durations, load types, and bucket teeth status. Sensor data is fused and fed into the DES model to replicate the earthmoving project. The proposed method is successfully implemented and validated in a large-scale earthmoving case study. The developed DES is proven promising as a reliable DSS for enhancing resource allocation and time-cost reduction.

Authors: Poorya Mehrzad, Hosein Taghaddos, Ala Nekouvaght Tak

Abstract:

Building materials, mainly steel and concrete used in residential buildings, significantly impact CO₂-eq emissions. Nowadays, carbon tax policy is used in some countries to reduce carbon emission effects. However, few comprehensive studies have been conducted to investigate the overall impact of such a carbon tax policy on minimizing building CO₂-eq emissions. Stakeholders in the building industry often focus on cost criteria to select construction materials, neglecting environmental factors. Providing a cost-emission framework can be beneficial in choosing appropriate materials based on financial and environmental factors. This study proposes a comprehensive framework to analyze the embodied CO₂ equivalent emission, carbon taxation, and cost of steel and Reinforced Concrete (RC) structures employing Life Cycle Assessment (LCA) methodology. The framework is implemented on an actual residential building case study to validate its potency. The case study’s results show that the embodied CO₂-eq emission of the RC structure is 36% higher than the emission in a similar steel structure leading to 36% more carbon taxation. However, the total material cost of the steel structure is around 65% higher than the RC structure. Thus, carbon taxation policy does not necessarily reduce embodied CO₂-eq emissions because stakeholders may prioritize the cost criteria to select building materials.

Authors: Kamyab Aghajamali, Ala Nekouvaght Tak, Hosein Taghaddos, Ali Mousaei, Saeed Behzadipour, and Ulrich Hermann

Abstract:

The trend toward more compact designs and congested site layouts makes it challenging for lift planners to provide feasible lift paths for mobile cranes, confronting the added risk of potential collisions when maneuvering through on-site obstacles. In some cases, particularly in congested industrial modular projects, it is inevitable for mobile cranes to walk with loads to a position with sufficient clearance to perform the lifts and place the objects in their final set position. This study contributes to the body of knowledge by introducing a comprehensive lift planning framework to plan complicated lifts involving mobile crane walking operations. Due to the lack of reliable and accurate plans for such lifts in practice and the added complexities, they are often eluded by practitioners compared with the more straightforward pick-and-set scenarios. This study proposes an algorithm for optimized planning of crane walking–involved lift operations borrowing an obstacle avoidance technique from robotics. The proposed path planner thoroughly considers site constraints and crane configurations to prevent collision between the crane body and the load with preinstalled objects. Actual case studies are presented to validate the efficiency of the proposed algorithm. The system generated the presented real-world lift in less than 5 min, satisfying the operations’ optimality, safety, and feasibility.

Authors: Amir Sadatnya, Naimeh Sadeghi, Sina Sabzekar, Mohammad Khanjani, Ala Nekouvaght Tak, Hosein Taghaddos

Abstract:

Construction productivity estimation lacks a comprehensive, standard, and task-type-independent framework to generate and serialize Machine Learning (ML) models. This research aims to develop an ML management framework for estimating the work crew productivity (crew outputs over their working hours) by addressing various operation and project types. The framework takes advantage of historical data, including information regarding operations’ progress, weather conditions, the number of resources, and their composition in a work crew. Daily work reports are used as a principal source of historical data. Various hyperparameters-tuned ML algorithms are adopted and ranked based on their computational complexity and prediction accuracy. The generated productivity prediction models have the flexibility to be reused for the effective planning of various construction projects. Applying the proposed framework to a case study of nine disciplines provided estimation models with high accuracies. This study also discusses the theoretical and practical implications of the presented model development procedure.

Authors: Vahid Zamani, Hosein Taghaddos, Yaghob Gholipour

Abstract:

A reliable Decision Support System (DSS), particularly in the construction domain, can be driven by quality input information. Although vision-based methods have been widely utilized to retrieve contextual information, their potential is not fully leveraged in construction simulation yet. This study introduces an automated framework that utilizes multi-view video footage for vision-based input modeling within simulation domains. The proposed framework addresses project uncertainties (e.g., equipment performance, operators’ skills, road network, and weather status) using a proactive approach where project task durations are modeled as probabilistic distributions. The modeled distributions are continuously calibrated using the Markov Chain Monte Carlo Bayesian Inference (MCMCBI) approach. A simulation-based Simulated Annealing (SA) optimization is also employed to provide an efficient resource assignment. The extracted vision-based data is validated statistically against actual and spatiotemporal data. The results demonstrate that the suggested vision-based approach can provide qualified DSS input. Statistical analysis also confirms that vision-based data is more consistent with actual data than spatiotemporal data. The presented approach is successfully applied to an actual case study of a large-scale earthmoving project.

Authors: B. Sherafat, H. Taghaddos, E. Shafaghat

Abstract:

Material quantity take-off is a necessary factor in estimating the cost of construction projects; accordingly, fast and precise estimations would better facilitate the overall construction process. In recent years, several Building Information Modeling (BIM) based applications (e.g., Autodesk Revit, Tekla Structure, Autodesk Navisworks Manage, and Solibri Model Checker) have emerged to assist in performing quantity take-off. Quantity take-off measurement using these applications is accurate when the elements length multiplies with their precise section area. Still, the process encounters errors when using element volumes or Industry Foundation Classes (IFC). In this study, the authors examined the embedded quantity take-off feature of these applications for sample steel and reinforced concrete structure and provided precautions in employing BIM properties. Consequently, an automated approach has been applied to facilitate an accurate quantity take-off by using an Application Program Interface (API) extracting information from a Navisworks model as well as database management systems. A case study is subsequently presented to demonstrate and validate the proposed methodology.

Authors: Sahar Alirezaei, Hosein Taghaddos, Khashayar Ghorab, Ala Nekouvaght Tak, Sepideh Alirezaei

Abstract:

Despite the acknowledged promises of adopting technologies such as BIM and AR, research addressing the challenges and opportunities of such synergies in cost and schedule risk management is still limited. This paper contributes to the literature by presenting an integrated, proactive BIM-Augmented Reality (AR) risk management system enabling an online inspection of project cost and schedule risks. This system records the actual risk data (e.g., risk type and likelihood) using AR on commercial smartphones, runs an online Risk Failure Mode and Effects Analysis (RFMEA), and updates the project’s BIM model to provide informed risk-related solutions. A case study is provided to demonstrate the implementation of the proposed system in a real project. Despite the challenges cited in the post-implementation survey (e.g., system ergonomics and synchronizations of automated/non-automated subsystems), 67% of the users acknowledged the improvement in cost and schedule risk management owing to enhancement in communication, timeliness, and risk perception.

Authors: Zahra Kamal, Hosein Taghaddos, Saeid Metvaei

Abstract:

Work order management in hospitals that are dynamic and high-pressured environments is a significant challenge. Healthcare Repair and Maintenance (R&M) managers need to plan work orders precisely, quickly, and cost-effectively according to technical and administrative aspects and resource limitations. This paper develops a new framework to optimize R&M schedules in hospitals by minimizing direct and indirect costs (personnel, travel, and delay costs), considering managers’ preferences and constraints. The proposed framework integrates Building Information Modeling (BIM), Genetic Algorithm (GA), and Discrete Event Simulation (DES) to discover the optimum plan for R&M tasks and employs BIM and Augmented Reality (AR) to support on-site activities by navigating and retrieving information. The proposed framework enables healthcare managers to reduce the time and costs of R&M plans and utilize personnel more efficiently. Implementing this system on an actual case study proves its capabilities in basing a good foundation to provide personnel’s visualized work packages automatically.

Authors: Amir Shekargoftar, Hosein Taghaddos, Amir Azodi, Ala Nekouvaght Tak, Khashayar Ghorab

Abstract:

To maintain underground utilities in a safe condition, the need for a comprehensive management and maintenance system is becoming more prominent. There are several problems with the current operation maintenance applications in underground utilities, including the lack of a digitalized 3D model with a comprehensive database for dynamically editing data on the site. This research proposes a pipeline operation and maintenance management system (POMMS) by employing building information modeling (BIM), geographic information system (GIS), and augmented reality (AR) and integrating various project information sources through application programming interface (API) and cloud database. This system can facilitate decision-making by more realistic 3D visualizations, enhanced integration of construction, geographic and inspection information, and efficient data retrieval. The proposed system is applied to an actual project to validate its efficiency. In this research, two scenarios and one survey were conducted to investigate the performance of POMMS. The case study and survey results indicates POMMS’s efficiency in improving data collection, communication among stakeholders, and perception of as-built subsurface utility map while unfolding several crucial challenges and limitations of real-world implementation of the system.

Authors: Vahid Zamani, Hosein Taghaddos, Yaghob Gholipour, Hamid Reza Pourreza

Abstract:

One of the state-of-the-art computer vision applications is scene understanding and visual contextual awareness. Despite the numerous detection and classification-based studies, the literature lacks semantic segmentation methods for a more comprehensive and precise understanding of the soil included scene due to the scarcity of annotated datasets; the extracted information from an understood scene is worthwhile in project fleet management, claims management, equipment productivity analysis, safety, and soil classification. Hence, this study presents a vision-based approach for soil-included scene understanding and classifying them into different categories according to ASTM D2488, using semantic segmentation. An annotated dataset of various soil types containing 3043 images was developed to train four Deeplab v3+ variants with modified decoders. Five-fold cross-validation indicates the remarkable performance of the best variant with a mean Jaccard index of 0.9. The application and effects of subpixel upsampling and exit-flow CRF were also examined.

Authors: M. Dadashi Haji, H. Taghaddos, M.H. Sebt, F. Chokan, M. Zavari

Abstract:

Building information modeling (BIM) has attracted considerable interest in the area of 4D simulation. The performance and benefits of the 4D simulation can be affected by different factors, such as the organizational integration of the teams involved in the project and the models’ content, which is recognized as the maturity level of BIM. Despite the various advantages of implementing 4D BIM and the significance of obtaining the full potential of 4D simulation, there is a scant number of researches that have considered this issue. Thus, this study aims not only to assess the relationship between the performance of 4D simulation and different maturity levels but also to clarify the required Level of Development (LOD) and maturity level in BIM application to synchronize the BIM implementation process with its expected benefits. For this purpose, the differences in gained benefits of implementing 4D BIM in various projects, which had different BIM maturity levels, were examined. The results showed that promoting the integration of the BIM implementation process, considering suitable LOD for modeling, and clarifying the expectation from different parts of a project lead to an enhancement in the performance of BIM 4D simulation.

Authors: Mohammad Saleh Dashti, Mohammad RezaZadeh, Mostafa Khanzadi, Hosein Taghaddos

Abstract:

The time-space conflicts may have severe negative impacts on the productivity and safety level in a construction site. However, little attention is paid to propose an automated, integrated system for managing potential time-space conflicts, considering the site space system’s dynamic nature. This study contributes to the body of knowledge by proposing a novel integrated approach to manage time-space conflicts automatically. The proposed hybrid approach is based on Discrete Event Simulation (DES), Building Information Modeling (BIM), and Rapidly-exploring Random Tree (RRT) path planning. All types of time-space conflicts during the entire project timeline are automatically detected, evaluated, and resolved based on predefined if-then rules. The proposed approach is applied successfully in a real case study to estimate the project duration considering site space limitations. The results indicate that the proposed system can considerably prevent the negative impacts of time-space conflicts, particularly in congested construction sites.

Authors: Ali Mousaei, Hosein Taghaddos, S.Marzieh Bagheri, Ulrich Hermann

Abstract:

Planning lift activities of mobile cranes for a modular project can raise productivity and improve safety. An optimized lift plan is essential for multiple lifts due to high rental cost of heavy lift cranes. However, choosing among a large number of available lift options (e.g., types, configurations, and locations of cranes) to develop multilift plans can be challenging. Despite numerous efforts in this area, there is still room for improvement to enhance the optimality of solutions, which leads to considerable cost reduction. This paper introduces an integrated framework to automatically generate an optimum lift plan based on a predetermined lifting sequence. Dijkstra’s search algorithm is utilized in the current study to select each module’s optimum lift option. This study contributes to the body of knowledge by proposing an enhanced graph-based optimization algorithm for multiple concurrent heavy lift operations. The suggested framework is validated successfully in an actual modular construction project in Alberta, Canada. The results are also compared with the previously developed lift planning algorithms, showing a remarkable reduction in the project’s total cost.

Authors: Hosein Taghaddos, Mohammad Hosein Heydari, Amirhossein Asgari

Abstract:

Purpose This study aims to propose a hybrid simulation approach for site layout and material laydown planning in construction projects considering both the project’s continuous and discrete state. Design/methodology/approach Efficient site layout planning (SLP) is a critical task at the early stages of the project to enhance constructability and reduce safety risks, construction duration and cost. In this paper, external and internal conditions affecting SLP gets identified. Then dynamic features of project conditions and project operations are analyzed by using a hybrid simulation approach combining continuous simulation (CS) and discrete event simulation (DES). Findings An efficient site layout plan regarding the project conditions results in cost efficiency. Instead of using DES or CS alone, this paper uses a hybrid simulation approach. Such a hybrid method leads to more accurate results that enable construction managers to make better decisions, such as material management variables. The proposed approach is implemented in a real construction project (i.e. earthmoving operation) to evaluate the hybrid simulation approach’s performance. Practical implications The proposed approach is implemented in a real construction project (i.e. earthmoving operation) to evaluate the performance of the hybrid simulation approach. Originality/value Although DES is used widely in construction simulation, it involves some limitations or inefficiencies. On the other hand, modeling resource interactions and capturing the construction project’s holistic nature with CS or system dynamics face some challenges. This study uses a hybrid DES and CS approach to enhance commercial construction projects’ SLP.

Authors: Zahra Kamal, Hosein Taghaddos, Hossein Karimi

Abstract:

The reliable maintenance management system of medical equipment influences the patients’ treatment and the hospitals’ performance. Although building information modeling (BIM) technology has evolved the construction industry, it does not fully comply with the facility management (FM) industry, particularly with repair and maintenance. BIM-based FM provides a structured platform to effectively capture necessary data during the construction stage for effective facility maintenance management (e.g., prioritizing maintenance work orders). Despite the design improvements and preventive maintenance plans, unplanned failures are inevitable and need quick and appropriate reactions. This paper introduces an integrated BIM-based framework for effective facility maintenance management. This framework consists of an integrated maintenance database for medical equipment, a scheduling engine to prioritize and sequence work orders, and a 4D simulation module to visualize the work-order handling process semiautomatically. Case-based reasoning (CBR) is also employed in the simulation engine to capture expert knowledge and facilitate the sequencing process. The proposed framework’s capabilities are demonstrated by applying and validating in a national healthcare facility in Iran.

Authors: Ali Mousaei, Hosein Taghaddos, Ala Nekouvaght Tak, Saeed Behzadipour, and Ulrich Hermann

Abstract:

Improper planning and management of heavy lifts is a major cause of cost overruns, delays, and, more importantly, safety incidents in industrial megaprojects. Automated lift planning is widely acknowledged as an effective solution. This research presents an automated lift path planning system for mobile cranes leveraging space discretization and an obstacle-avoidance technique from robotics. The proposed method treats the lifted object as a three-degree-of-freedom convex traveling through the surrounding environment [a given two-dimensional (2D) elevation] with discretized rotational and translational motions in polar coordinates. It efficiently finds the best feasible pick location and optimized collision-free lift path in the polar coordinate system to the set location. This system is a state-of-the art advancement in crane path planning because it mimics the crane’s intrinsic behavior and generates paths considering cost functions for safety, practicality, and economic objectives to enable its implementation in real practice settings. Illustrative examples are presented to verify the proposed approach and demonstrate its superiority over past similar path planning systems in terms of optimality and operational ease.

Authors: Mohammad Hosein Nili, Hosein Taghaddos, Banafsheh Zahraie

Abstract:

To minimize agency and user costs in a bridge repair project, a bridge maintenance manager should develop an appropriate project schedule considering real-world constraints such as resource limitations (e.g., workspace and crew). This paper presents a new framework called Simulation-based Bridge Maintenance Optimization (SiBMO) by integrating Genetic Algorithm (GA) and Discrete Event Simulation (DES) to identify the optimum maintenance plan taking into account crew limitations. The framework optimizes the sequence of repair-activities in the repair interventions considering workspace limitations and predecessor relationships. SiBMO also develops a high-level schedule of the interventions regarding the project calendar and the Traffic Management Plan (TMP). The Bridge Information Model (BrIM) based user interface developed in this study visualizes the high-level schedule. The results of applying SiBMO on a real case study demonstrates its capability in finding the optimum maintenance plan, its efficiency in optimizing the high-level schedule, and its accuracy in estimating user costs.

Authors: Maedeh Motalebi, Mohammad Mahdi Nasiri, Hamed Shakouri G., Hosein Taghaddos

Abstract:

In this reserach, a multi-objective model is presented considering simulated behavior of high-efficiency rooftop solar PV panels in factory, which are among the largest producers of green-house gases. The paper proposes a simulation-optimization approach is used to maximize the net present value (NPV) of economic benefits along with minimizing the payback period (PBP) of the investment, and maximizing solar energy consumption rate (SECR). In addition, the solar PV panels degradation and maintenance cost, as well as the uncertainty in solar irra-diance and demand load, are also considered. The study consists of two scenarios, in the first of which both electricity tariffs and feed-in-tariffs (FiT) are fixed by a long-term contract. The second scenario investigates the situation in which subsidies on electricity tariff are removed. The best type of panels are found in each scenario considering trade-off between objective functions. The preferred trade-off solution in the first scenario, with 2% increase in PBP, achieves more than 10% growth in NPV which is about $15000 in a year. In the second sce-nario, with only about 0.2% decrease in NPV and 3% increase in PBP, the preferred solution attains 9% increase in SECR.

Authors: Mohammad Hosein Nili, Banafsheh Zahraie and Hosein Taghaddos

Abstract:

    Effective bridge maintenance reduces bridge operation costs and extends its service life. The possibility of storing bridge life-cycle data in a 3D parametric model of the bridge through Bridge Information Modeling (BrIM) provides new opportunities to enhance current practices of bridge maintenance management. This study develops a Decision Support System (DSS), namely BrDSS, which employs BrIM and an efficient optimization model for bridge maintenance planning. The BrIM model in BrDSS extracts basic data of elements required for the optimization process and visualizes the inspection data and the optimization results to the user to help in decision makings. In the optimization module of the DSS, the specifically formulated Genetic Algorithm (GA) eliminates the chances of producing infeasible solutions for faster convergence. The practicality of the presented DSS was explored by utilizing the DSS in the maintenance planning of a bridge under operation in the southwest of Iran.

Authors: Atiye Farahani, Hosein Taghaddos, Mohammad Shekarchi

Abstract:

Chloride-induced corrosion is the main cause of premature deterioration and failure of RC structures in corrosive environments. Therefore, modeling chloride permeation and investigating different methods for the repair and maintenance of RC structures exposed to corrosive marine environments are very important for optimizing the service life and life-cycle cost of these structures. This study introduces a prediction model for the chloride diffusion coefficient for portland cement (PC) RC under long-term exposure in the tidal zone of a marine site of southern Iran. A regression analysis (R2=0.9972) best fit was performed to check the accuracy of the prediction model based on Fick’s second law of diffusion. Various thickness equivalents for surface coatings were simulated as repair methods for the maintenance of RC structures exposed to corrosive marine environments. A finite-element model is provided for analysis to assess the time-dependent capacity of corroded RC structures using nonlinear analysis and the impact of corrosion on inelastic buckling of reinforcements. This analysis investigated and compared the influence of a number of repair or rehabilitation methods on the performance of a corroded square RC column due to chloride-induced corrosion, including concrete surface coatings used on the external surface of concrete, and increasing concrete cover thickness repair after the initial cracking of concrete cover. Results indicated that, compared with the no-repair scenario, the corrosion percentage of longitudinal bars of PC concrete with water-to-cement ratios of 0.35, 0.40, and 0.50 decreased 58.8%, 6​4​

Authors: Hossein Karimi, Hosein Taghaddos

Abstract:

Over the past two decades, the construction industry has encountered the challenge of rapid aging of craft workers in many countries. In addition, the shortage of skilled workers that has emerged over the past three decades in various countries have forced project managers, at least in some regions or periods of time, to execute projects with less skilled or experienced workers. There has been increasing attention from researchers and practitioners on fatal injury preventive solutions. However, the industry still suffers from a relatively high and substantial disproportion in fatal injuries compared to other industries. This study contributes to the body of knowledge by elucidating the fatality rate fluctuations in the different age groups of craft workers and empirically examining the interaction of adverse impact of higher age and preventive influence of higher educational attainment and skill and experience level of craft workers on fatal injuries in construction projects. A total of 6,326 accidents were analyzed, which occurred in construction projects in the province of Tehran, Iran between 2011 and 2017. The study found the higher experience and educational attainment of craft workers significantly mitigates the severity of accidents from fatal injuries to nonfatal ones in young and middle-aged craft workers. However, the effectiveness of both factors decreases gradually when craft workers get older. Both factors’ strength will be dominated by the adverse impact of age on the older workers, which results in a high fatality rate between the age of 65 and 75.

Authors: Hossein Karimi, Hosein Taghaddos

Abstract:

Despite long-term improvement in construction safety over the past decades, this industry still suffers from significant disproportion and high fatality rate compared to other industries. It is widely accepted that human error is one of the main contributors to the majority of accidents in construction projects. Building based on controlling the consequence of human errors as a more productive approach compared to striving for their elimination, this study examines the influence of education and experience level of construction craft labors in mitigating the outcome of human errors. The study contributes to the body of knowledge by quantitatively elucidating the influence of craft workers’ educational attainment and experience level on controlling the consequence of accidents specifically alleviating the fatal injuries to non-fatal ones in construction projects. A total number of 6,355 accidents occurred in construction projects in Tehran Province, Iran between 2011 and 2017 were analyzed. The results of the analysis show that in majority of accidents, higher educational attainment in craft workers resulted in significant lower risk of fatal injuries. In addition, the results indicate that in most accidents, the higher level of experience substantially reduces the fatality rate. It is also demonstrated that education and experience are independent of each other which makes both variables noteworthy for the intended purpose. The study suggests industry leaders, managers and construction stakeholders that one of the fundamental solutions to chronic problem of high fatality rate in construction projects is investing on hiring process, educational programs, rigorous training and retaining of craft workers.

Authors: H. Taghaddos, A. Eslami, U. Hermann, S. AbouRizk, Y. Mohamed

Abstract:

In modular industrial construction, prefabricated modules are usually lifted with mobile cranes. Development of reliable heavy lift plans using conventional planning tools, however, remains a challenging and time-consuming task. This article presents an Auction-based Simulation for Industrial Crane Operations (ASICO)—a powerful and flexible auction protocol-based simulation model designed to facilitate heavy lift plan development. Employing this powerful approach enables lift planners to select the best types of cranes, to schedule multiple heavy lifts while satisfying system constraints, and to determine proper configurations, crane locations, and pick-points. Specifically, AISCO reads data from a comprehensive database to allocate cranes, with appropriate configurations and locations, to modules (known as agents). ASICO then holds a number of regular auctions (e.g., every working day), where agents bid for various combinations of resources (e.g., cranes, space). In this system, an auctioneer is designed to solve the Winner Determination Problem (WDP) based on combinatorial optimizations by maximizing the social welfare of the entire system. ASICO also provides suitable scheduling data for a 4D (3D plus time) animation tool to demonstrate the lifting process throughout the entire construction phase. Implementation of this system on a real case study was found to improve the cost, schedule, and safety of the project.

Authors: Atiye Farahani, Hosein Taghaddos, Mohammad Shekarchi

Abstract:

In this paper, an empirical model is developed for predicting the chloride diffusion coefficient for silica fume, metakaolin, zeolite, and portland cement (PC) concretes under long-term exposure in the splash zone of Qeshm Island, Iran. All investigations are based on 12 concrete mixture designs exposed to seawater for a maximum period of 50 months. The empirical model is developed by applying regression analysis based on Fick’s Second Diffusion Law on the experimental results and those are compared with previous studies in this area. These comparisons indicate that the predicted chloride diffusion coefficient level is within a ±25% error margin in the specimens.

Authors: Mostafa Khanzadi, Mohammad M. Shahbazi & Hosein Taghaddos

Abstract:

The uncertainty of a project presents a challenge to time management. The promise reliability of assignees at the task level is a key source contributing to this uncertainty. Despite its importance, little research has studied the impact of promise reliability of assignees on reliability of project schedules. This paper proposes a method which, based on the rate at which assignees kept their promises in previous activities, calculates the probability of keeping their promises in upcoming activities and calculates the probabilistic duration of project. The results obtained from the case studies reveal that the reliability of assignees’ promises has a significant impact on the probability of finishing the project in time. It is also shown that replacing a tardy agent with a punctual one reduces the project duration. More importantly, there is an optimal task–agent relationship (i.e., team arrangement), for which the project duration is minimal. This method can also highlight the unreliable paths in a CPM network. Despite its traditional basis, the method is of practical value to the recent work planning methods, which advocate short-term planning in a collaborative manner.

Authors: Hosein Taghaddos, Ulrich Hermann, ArioBarzan Abbasi

Abstract:

The majority of industrial projects in Alberta’s oil sands are constructed using modular construction. Modules are preassembled components built off-site and transported to the site to be lifted into place with mobile cranes. Heavy lifts include modules as well as major equipment that utilize expensive mobile cranes. Selecting the proper mobile cranes and configurations and finding the best crane position for each lift saves a significant amount of time and cost, while also improving safety. A heavy lift plan facilitates overall site management by reducing extra crane relocations and avoiding dangerous crane clashes. Performing such intensive analysis manually for several hundred lifts and various crane options is a tedious, prolonged exercise. However, no application that carries out such intensive analysis for a number of lifts in modular construction has yet been developed. This paper presents a system, called Automated Crane Planning and Optimization, to automate the above-mentioned analysis for a large-scale project. This system is validated on actual modular projects.

Authors: Di Hu, Yasser Mohamed, Hosein Taghaddos, Ulrich Hermann

Abstract:

The generation of well-defined and moderately sized field installation work packages for the construction workforce, referred to as workface planning, has been recently employed to plan large-scale industrial construction projects under tight schedules. However, traditional CPM-based scheduling of several thousand work packages (e.g. 5000 activities multiply by 10 work packages per activity on average) is a tedious, error prone process. Defining proper logics and controlling congestion among work packages crossing several work areas, and also effective resource allocation over time are other major challenges in workface planning. This paper presents a novel simulation-based framework to implement workface planning for large-scale industrial construction projects. This framework proposes a time-stepped discrete event simulation-based modelling for dynamic resource allocation based on congestion and other constraints on the job site. The proposed method is demonstrated and tested against traditional CPM-based solutions based on an actual case study.

Authors: Atiye Farahani, Hosein Taghaddos, Mohammad Shekarchi

Abstract:

Chloride-induced corrosion is the main factor in determining the durability and service life of the reinforced concrete structures exposed to marine environments. Recognition of chloride diffusion phenomenon in concrete and developing a prediction model that can estimate the service life of the concrete structures subject to long-term exposure is vital for aggressive marine environments. The present study focuses on developing such a prediction model of chloride diffusion coefficient for silica fume concrete under long-term exposure to a durability site located in the southern region of Iran. All investigations are based on 16 concrete mix designs containing silica fume with variable water-to-binder ratios exposed to sea water for maximum period of 60 months. This empirical model is developed by applying regression analysis based on Fick’s second law on the experimental results and is compared with previous studies in this area. This comparison indicates that the predicted chloride diffusion coefficient level is within a ±25% error margin in the specimens. The results indicate that reducing the water-to-binder ratio and adding the silica fume to a dosage of 10% reduces the chloride diffusion coefficient in concrete. This study also confirms that the chloride diffusion coefficient increases with temperature and decreases over time.

Authors: Zhen Lei, SangHyeok Han, Ahmed Bouferguène, Hosein Taghaddos, Ulrich Hermann, and Mohamed Al-Hussein

Abstract:

On-site construction of industrial projects relies heavily on large mobile cranes for the lifting of prefabricated modules, which over the years have become heavier and more voluminous. Industrial construction sites are frequently congested, a condition that reduces the area where cranes can freely maneuver. As a result, in some cases mobile cranes may not have sufficient clearance to perform the lifts and thus need to pick and walk with loads to a point from which the modules can ultimately be set in their resting positions. Since this type of crane operation presents higher risks of failure or accident in comparison to the traditional scenario, in which the location of the crane does not change for the duration of the lifting, a detailed analysis of these operations is paramount to ensure safety and efficiency. Paradoxically, many practitioners still rely on their best judgment for crane walking planning, which in the case of highly congested and complex construction sites is likely to lead to inefficiencies and errors since numerous obstacles may interfere with the crane body and the load. Furthermore, manual analysis is tedious, time-consuming and cannot respond rapidly to changes in work orders or project scope, especially considering the large number of lifts involved in modern industrial projects. In this paper, a generic algorithm is proposed for mobile crane walking path planning, which considers the typical site constraints, the geometry of lifted modules, and crane configuration. The proposed algorithm calculates the pick area and crane collision-free operation area, based upon which the crane’s walking paths are determined. A case study, based on an actual industrial project, is presented to validate the developed algorithm.

Authors: Zhen Lei, Hosein Taghaddos, Jacek Olearczyk, Mohamed Al-Hussein, Ulrich Hermann

Abstract:

At present, industrial projects are constructed primarily using a prefabricated approach. The modules are produced in an off-site facility and transported on transport trailers to the construction site where they are lifted by mobile cranes. One of the keys to the success of modular industrial projects is efficient crane planning, which includes path checking to find whether or not a crane has a feasible path through which to lift a module over obstructions in a congested plant. However, due to the large number of lifts, the manual path-checking practice is quite tedious and prone to error. In light of this problem, this paper proposes a methodology for automatically checking the lift paths for industrial projects. The proposed methodology simplifies and represents the three-dimensional site layout using project elevations. For each elevation, the crane feasible operation range (CFOR) is calculated based on the crane’s capacity and clearances, as well as site constraints. The pick area (PA) is calculated by subtracting the ground obstruction areas from the CFOR. The relative positions of the module’s set point, the CFOR, and the PA are checked to determine the feasibility of the lift path on each elevation, as well as the project elevation combination. This approach has been fully automated for path checking of entire sites, and the results are responsive to site changes over time as a project progresses. This proposed methodology is generic and thus can be easily applied to check lift paths for entire industrial plants or similar projects.

Authors: Zhen Lei, Hosein Taghaddos, Ulrich Hermann, Mohamed Al-Hussein,

Abstract:

Industrial projects are constructed in the form of prefabricated modules that are transported to sites for installation, a process which enhances efficiency and productivity. As these prefabricated modules become heavier, proper lift planning is essential for onsite efficiency and safety. One aspect of the heavy lift study is to check the path feasibility for specific lifted modules. Current practice in path checking process is tedious and prone to errors. This paper proposes a generic method for mobile crane lifting binary (yes-or-no) path checking. The methodology calculates the minimum and maximum crane lift radii based on capacity and the crane’s configuration, which are then modified considering site constraints. The modules’ erection orders are also taken into consideration, and a configuration space approach is used to simplify the work space. The modified radii and simplified work space are merged with the lifted module pick area for path checking. The methodology is incorporated into a computer module for automatic calculation and visualization. A case study involving an industrial project is provided for validation and to highlight the designed computer module’s essential features.

Authors: Hosein Taghaddos, Hamid Soleymani

Abstract:

Most standardization agencies allow small-cylinder specimens (100 x 200 mm [4×8 in.]) to be used in compressive strength concrete testing. Some engineers are still skeptical about using small cylinders, however, as they believe that compressive strength testing results from small cylinders are too varied. Limited studies have been conducted regarding the precision of small cylinders compared to precision studies for conventional cylinders (150 x 300 mm [6×12 in]). This paper describes the results of a comparative concrete testing program conducted by 15 laboratories in Edmonton, AB, Canada, over the past 10 years. This study attempted to develop within-laboratory (repeatability) and between laboratory (reproducibility) precision indexes for small and conventional concrete specimens by analyzing more than 2700 compressive strength concrete testing data within a compressive strength range of 17 to 57 MPa (2500 to 8300 psi).

Authors: Hosein Taghaddos, Simaan M. Abourizk, Yasser Mohamed, Ulrich Hermann

Abstract:

Resource scheduling, or the allocation of resources over time, is a challenging problem in large-scale or multiple-project environments. Traditional network scheduling techniques are ineffective in modeling the dynamic nature and resource interactions of large or multiunit projects. This paper presents a simulation-based auction protocol (SBAP) to solve resource scheduling problems in large-scale construction projects. SBAP is a hybrid framework that integrates multi agent resource allocation (MARA) in a simulation environment. SBAP deploys a centralized resource allocation approach, referred to as an auction protocol, whereby agents bid on different combinations of resources at the start of a simulation cycle. Agents attempt to improve their individual welfare by acquiring a combination of resources; an auctioneer looks at the entire system and allocates resources to the agents using a combinatorial algorithm to maximize an overall objective function (e.g., maximizing the system’s revenue or minimizing total costs). The auction is repeated on a regular basis. Simulation is also employed in large-scale projects to track the availability of resources, capture and release the resources, and satisfy constraints of the problem. This paper demonstrates the architecture of the SBAP framework and discusses implementation of SBAP in a real case study of crane allocation in an industrial project. DOI: 10.1061/(ASCE)CO.1943-7862.0000399. (C) 2012 American Society of Civil Engineers.

Authors: Hosein Taghaddos, Ulrich Hermann, Simaan M. Abourizk, Yasser Mohamed

Abstract:

Modular construction is a common practice for building industrial plants, particularly in the oil sands region of Alberta, Canada. Each module is a project with its own activities and constraints. These modules are prefabricated offsite, at a location called the module assembly yard, and then shipped to the site. Effective scheduling of modules of an industrial plant involves developing a realistic schedule that makes best use of limited resources in the yard while satisfying the constraints and uncertainties of the entire project. Scheduling such large-scale, multiunit projects using commercial CPM-based scheduling applications (e.g., Primavera, Microsoft Project) is not effective. In previous work, we have introduced a hybrid framework, called simulation-based auction protocol (SBAP), for effective resource scheduling in large-scale projects. The present study employs the SBAP framework for effective allocation of resources (e.g., space, skilled crew) and for satisfaction of various constraints. This system pulls data from a comprehensive database, runs the simulation model behind the scenes, and generates various graphical reports to aid superintendents and project managers in pertinent project decisions. The developed system is also capable of scheduling the fast-track modular construction projects with limited data available, doing effective resource leveling, and scheduling resources (e.g., space, crew) effectively based on various shifts and calendars. The described case study in this paper demonstrates the capabilities of the developed system for planning the module assembly yards.

Authors: Zhen Lei, Hosein Taghaddos, SangHyeok Han, Ahmed Bouferguène, Mohamed Al-Hussein, Ulrich Hermann

Abstract:

Modular construction is a dominant manufacturing method for industrial construction in Alberta, Canada. Modularization requires large-capacity mobile cranes to lift heavy modules, such as piperack modules. The current practice utilizes AutoCAD to generate heavy lift studies for modular onsite installations. Heavy lift studies consist of 2D and 3D simulations of the lifting scenarios, along with the corresponding calculations (e.g., lifting capacity checking, ground bearing pressure checking). These static simulations provide snapshots of mobile cranes at pick and set configurations, but they do not represent the movements between the two configurations. For better communication among site engineers and crews, current static heavy lift studies need to be improved by animating the entire lifting process. 3ds Max is an animation tool that can visualize the lifting process, but the tedious and manual process of preparing the animation restricts efficiency and productivity. This research thus introduces a newly developed animation system that automates the transfer of heavy lift studies from AutoCAD into Autodesk 3ds Max animation. Also in this research, the kinetics of mobile cranes are studied and generic crane movements are defined. Using MAXScript, a script is written to link the crane and project database for automatic generating of animations. This research aims to provide the construction industry with a generic method for automating the animation process for heavy lifts based on AutoCAD and 3ds Max systems.

نویسندگان: خشایار غراب، حسین تقدس

چکیده:

برنامه‌ی زمان‌بندی پروژه در صنعت ساخت‌وساز باعث دید یکسان بین ذینفعان پروژه می‌شود. به طور سنتی برای مشاهده‌ی برنامه‌ی زمان‌بندی از اسناد کاغذی استفاده می‌شود و ذینفعان به‌سختی درک عمیقی از آن پیدا می‌کنند. در حال حاضر، مدل‌سازی اطلاعات ساختمان (B‌I‌M) کمک شایانی به ذینفعان پروژه برای پیدا کردن درک عمیق‌تر از برنامه‌ی زمان‌بندی پروژه می‌کند. در پروژه‌ی حاضر، با ایجاد ارتباط مستقیم بین مدل B‌I‌M و مدل واقعیت افزوده (A‌R) توسط یک پایگاه داده‌ی ابری، چارچوبی برای ارتقاء تعامل ذینفعان با مدل چهاربعدی پروژه ارائه شده است. تفاوت پژوهش حاضر با مطالعات پیشین، بررسی و مقایسه‌ی مدل چهاربعدی چارچوب پیشنهادی با مدل چهاربعدی B‌I‌M در پروژه‌های خطی است. روش مذکور در یک مطالعه‌ی موردی خط لوله‌ی آب پیاده‌سازی و بازخوردهای مثبتی از مصاحبه با تیم مشاور پروژه گرفته شد. همچنین مشخص شد که با رفع موانع موجود، روش اشاره شده می‌تواند به‌عنوان روشی مناسب برای درک بهتر برنامه‌ی زمان‌بندی پروژه استفاده شود.

نویسندگان: خشایار آسیداسمعیلی، حسین تقدس، محمد سعید کریمی

چکیده:

در روش‌های برنامه‌ریزی متداول و سنتی در پروژه‌ها، فرض بر اجرای فعالیت‌ها بر مبنای سیستم مبتنی بر فشار (شروع فعالیت‌ها در زودترین زمان ممکن) است. سیستم‌های سنتی برنامه‌ریزی مبتنی بر فشار اغلب منجر به انواع ضایعات در پروسه‌ی ساخت می‌شوند، که به‌دلیل توزیع نادرست منابع است. ضایعات ایجاد شده در پروسه‌ی ساخت می‌توانند موجب آثار منفی، نظیر: افزایش زمان، هزینه و انتشار آلاینده‌ها شوند. در نوشتار حاضر، مفاهیم تولید ناب، نظیر: برنامه‌ریزی کششی، استاندارد کردن پروسه‌ی ساخت و پیاده‌سازی مفهوم سوپرمارکت، جهت شناسایی و رفع انواع ضایعات و همچنین گلوگاه‌های پروسه‌ی ساخت در فرایند برنامه‌ریزی پروژه‌های عمرانی بررسی شده است. همچنین جهت ارزیابی روش‌های برنامه‌ریزی مبتنی بر تولید ناب، شبیه‌سازی پیشامد گسسته‌ی سناریوهای مختلف مبتنی بر مفاهیم تولید ناب در قالب مطالعه‌ی موردی پروژه‌ی بتن‌ریزی فونداسیون پروژه‌ی مجتمع تجاری صورت پذیرفته است.

نویسندگان: مریم معظمی، حسین تقدس، مهران محمودی، آریوبرزن عباسی

چکیده:

پروژه‌های ساخت در حوزه‌ی نفت و گاز نیاز به بودجه‌ی سنگین و مدت زمان طولانی برای اجرا دارند. یکی از چالش‌هایی که پروژه‌های نفت و گاز با آن روبروست بحث تأخیرها و عدم بهره‌وری مناسب منابع است. اتمام پروژه‌ها با هزینه‌ی مشخص و در زمان معلوم نیازمند برنامه‌ریزی مناسب است تا بتوان پروژه را به‌موقع به بهره‌برداری رساند. تحقیق پیش رو سعی دارد با استفاده از ابزارهای نوین رایانه‌یی از جمله شبیه‌سازی ساخت چارچوبی را برای بهبود برنامه‌ریزی پروژه‌های ساخت خط لوله گاز معرفی کند. بررسی اثر تعداد منابع بر روند پروژه، تخمین مدت زمان واقع‌بینانه‌ی پروژه، افزایش بهره‌وری منابع، بررسی دقیق عملیات ساخت و در نهایت کاهش زمان و هزینه‌ی پروژه از اهداف این چارچوب است. چارچوب مدنظر با همکاری شرکت مهندسی و توسعه‌ی گاز ایران در قالب مطالعه‌ی موردی خط لوله‌ی انتقال گاز دهگلان به میاندوآب ارائه می‌شود.

نویسندگان: سید مجتبی متقی پور، حسین تقدس، احسان اله اشتهاردیان

چکیده:

در صنعت ساختمان بیشتر توجهات معطوف به مرحله‌ی طراحی و ساخت است. در حالی که طولانی‌ترین و پرهزینه‌ترین مرحله از دوران حیات پروژه، مرحله‌ی بهره برداری از ساختمان است. موجود بودن، در دسترس قرار داشتن، به‌روزرسانی و قابل اعتماد بودن اطلاعات راجع به ساختمان و همچنین وجود ابزار مناسب برای مدیریت این اطلاعات، مسئله‌یی حیاتی برای مدیریت کارآمد تسهیلات ساختمان است. در دوران بهره‌برداری اطلاعات ساختمان نظیر دما، رطوبت و مقدار گازهای محیطی که بیانگر وضعیت واقعی و بهنگام ساختمان‌اند، توسط حس‌گرها قابل اندازه‌گیری‌اند. مدل‌سازی اطلاعات ساختمان (B‌I‌M) نیز بستر مناسب برای مدیریت این اطلاعات را فراهم می‌کند. با ادغام داده‌های بهنگام حس‌گر و B‌I‌M، زمینه برای بصری‌سازی، پایش و پردازش سطح عملکرد ساختمان به صورت بهنگام و خودکار فراهم خواهد شد. در نتیجه بازخوردهایی از وضع موجود در اختیار قرار می‌گیرد که با ارتقای قابلیت‌های تعمیر و نگهداری و ایمنی، به بهبود سطح عملکرد ساختمان کمک می‌کند. طرح پیشنهادی در یک ساختمان دوطبقه با کاربری مسکونی اعتبارسنجی شد.

نویسندگان: محمد رسولی منش، حسین تقدس، فرزاد چوکان، مصطفی داداشی حاجی، محمدحسین تمنایی فر

چکیده:

آسیب‌های جانی کارکنان پروژه را می‌توان به‌عنوان یکی از مهم‌ترین عوامل در ایمنی پروژه برشمرد. روش‌های سنتی مانند استفاده از نظر خبرگان و مستندات حوادث پیشین، کارایی پایینی در شناسایی و تعیین میزان خطر ریسک‌های ایمنی دارد و رویکردهای نوین، همچون: مدل‌سازی اطلاعات ساختمان، پیاده‌سازی فرایندهای شناسایی ریسک‌های ایمنی و رتبه‌بندی آن‌ها را امکان‌پذیر می‌کنند. در پژوهش حاضر، مدلی جهت شناسایی و معرفی ریسک‌های ایمنی در پروژه‌ها معرفی شده است که محرک‌های ایمنی را در نقاط مختلف پروژه شناسایی و رتبه‌بندی می‌کند. تأثیر عامل افزایش ارتفاع و جنس سطح زیرین برای ارزیابی خطر سقوط از ارتفاع بررسی و از مدل اطلاعاتی ساختمان برای مجسم‌سازی نتایج به‌منظور کاربرد در مدیریت ایمنی پروژه استفاده شده است. اطلاعات ورودی با استفاده از پردازش تصویر فراهم شده است که در پایگاه داده به مشخصات المان‌های ساختمانی مرتبط می‌شوند. نتایج حاصل از پژوهش حاضر به‌منظور پیش‌بینی مخاطرات سقوط از ارتفاع قابل استفاده است و قابلیت شناسایی و رتبه‌بندی نقاط حادثه‌خیز را دارد.

نویسندگان: عرفان شفقت، حسین تقدس، بهنام شرافت

چکیده:

متره و برآورد مصالح در پروژه‌های ساختمانی، اهمیت زیادی دارد. شرکت‌ها قبل از شروع به فعالیت در پروژه و در حین پیشبرد آن مایل‌اند که میزان مصالح موردنیاز پروژه را برای شرکت در مناقصه‌ها و خرید مصالح با دقت پیش‌بینی کنند. از این‌رو استفاده از نرم‌افزارهای مختلف مدل‌سازی اطلاعات ساختمان جهت متره و برآورد مصالح و سایر کاربردهای مهندسی و مدیریت ساخت به تازگی مورد توجه ذی‌نفعان پروژه‌ها قرار گرفته است. از پرکاربردترین نرم‌افزارهای مدل‌سازی اطلاعات ساختمان می‌توان از A‌u‌t‌o‌d‌e‌s‌k R‌e‌v‌i‌t و T‌e‌k‌l‌a S‌t‌r‌u‌c‌t‌u‌r‌e به منظور مدل‌سازی و نیز از A‌u‌t‌o‌d‌e‌s‌k N‌a‌v‌i‌s‌w‌o‌r‌k‌s M‌a‌n‌a‌g‌e جهت مدیریت سایت نام برد. در پژوهش حاضر، دقت متره و برآورد خودکار مصالح با استفاده از نرم‌افزارهای مذکور بررسی شده است. بدین منظور، ابتدا المان‌های فلزی و بتنی از طریق نرم‌افزار R‌e‌v‌i‌t و افزونه‌ی آن و سپس یک سازه‌ی بتنی و فلزی در دو نرم‌افزار T‌e‌k‌l‌a و R‌e‌v‌i‌t بررسی شده‌اند. درنهایت، نقاط ضعف هر یک از نرم‌افزارهای ذکرشده مشخص و پیشنهادهایی برای ارتقاء فرایند متره و برآورد مصالح مطرح شده است.

نویسندگان: امیر پور مقدم، حسین تقدس، فتح اله محمود زاده، محمد شکرچی زاده

چکیده:

در این بررسی برخی تحقیقات تحلیلی در مورد چیدمان و جهت گیری الیاف در بتن مسلح الیافی فلزی (SFRC) با توجه به مقادیر مختلف درصد الیاف انجام گرفته است. توابع پخشی مربوط به متغیرهای مکانی الیاف مورد بررسی قرار گرفته است که در نهایت بر اساس آن می‌توان مدلی تحلیلی برای پیش بینی خواص مکانیکی SFRC تولید کرد.
در این تحقیق با توجه به اثرات شرایط مرزی و نیز تابع پخش الیاف در هر مقطع مربع واحد (در بتن SFRC) بدست آمده است. در ضمن مقایسه ای بین نتایج حاصله از آزمایش و تئوری نیز انجام گرفته است که فرمولهای حاصله را تایید می‌کند.