Crane Lifting Research Articles

DISCRETE-TO-CONTINUUM MODELS IN ANALYSIS AND OPTIMIZATION (MINIMIZATION) OF DYNAMIC LOADS IN ELASTIC ELEMENTS/CARRIER CABLES OF HOISTING MACHINERY USED IN URBAN PLANNING AND TRANSPORT TECHNOLOGIES (PART I)

The analysis dynamic loads in elastic elements (ropes) of hoisting machines and cranes used in urban planning, loading and unloading operations and transport technologies was carried out. Discrete, continuous and discrete-continuous models of crane lifting mechanisms considered. In these models the elastic elements (ropes) are initially considered as elements that have elastic properties of the system with concentrated parameters. Therefore the rope in the lifting mechanism is taken into account as a certain rigidity spring. However, this approach is not correct for quite long ropes (more than 10 meters), in which wave processes can occur during lifting/lowering of loads. These processes can significally increase the dynamic loads − the so-called rope model as a system with distributed parameters. According to the authors of this work, the most correct approach is one that takes into account the discrete properties of the rope (more than 10 meters) itself. That is, the analysis of dynamic loads is carried out within a discrete-continuous model.
 The work consists of several parts, in each of which the dynamic loads in the ropes within each of above starting/braking of the crane lifting mechanisms models are comprehensively and in detail considered. Also parameters of work processes at which the above loads become optimal in magnitude calculated (that is, take the minimum values for different ways of lifting cargo: a)“from the base” (“from the ground”), b)“from the weith”, as, incidentally, the coefficient of dynamism.

BIM4D-based scheduling for assembling and lifting in precast-enabled construction

This research addresses the problem of assembly scheduling in crane-assisted precast construction while considering issues of building layout interference and optimal crane lifting. Traditionally, assembly scheduling and lifting path planning are treated as two separate issues due to their distinct natures. The current work introduces an approach that combines them for precast construction planning to achieve a comprehensive and cost-effective solution. A BIM4D-based Intelligent Assembly Scheduler (BIAS) is designed in conjunction with the Computer-Aided Lifting Planner developed at Nanyang Technological University, Singapore. BIM4D is the Building Information Modeling (BIM) with the time dimension (i.e., scheduling information). Our scheduler takes an inbuilt timeframe for selected precast elements from BIM4D as input and outputs the micro-schedule in terms of the assembly sequence for these precast elements. This problem is solved using multi-objective optimization. Given a group of precast elements and their BIM4D timeframe, the micro-scheduling is determined based on (1) the relative importance of the elements’ physical properties, (2) the interference (neighbouring relation) among the elements’ positions, and (3) collision-free lifting paths of the elements. A Multi-level Elitist Genetic Algorithm (MEGA) is proposed to determine the optimal sequence taking into consideration of both assembling and lifting for the elements. A case study is performed with the BIM4D data of a residential building. The results of the case study demonstrate BIAS's efficiency and effectiveness for BIM4D based construction scheduling.

Loading of the hydraulic cylinder of luffing of a lifting crane jib

A numerical simulation of the dynamic loading of hydraulic cylinders for luffing of a lifting jib crane in the following modes is carried out: continuous and sharp lifting of the load, sudden removal of the load from the jib, outrigger drawdown, luffing (jib lowering) For each mode, the graphs of deflections of the jib head and the hinge for attaching hydraulic jacks to the jib, reactions of hydraulic jack elements are determined. The amplitudes of the stresses of the rod and piston of the hydraulic cylinder are calculated taking into account the influence (stiffness) of the working fluid. Keywords: hydraulic cylinder of luffing, hydraulic cylinder of jib lifting, hydraulic jack. epotakhov@mail.ru

Lifting path planning of mobile cranes based on an improved RRT algorithm

Lifting operations of mobile cranes are one of the commonly-seen and most important activities for prefabrication housing production (PHP) on sites. However, relevant operations are normally based on the experience of operators or project managers, this often leads to low efficiency as well as high accident rate due to dynamic and complex construction sites. Thus, it is important and necessary to develop an appropriate approach to the lifting planning of mobile cranes so as to guide on-site operations. This paper proposes an improved Rapidly-exploring Random Tree (RRT) algorithm for lifting path planning of mobile cranes. Considering the critical role of Nearest Neighbor Search (NNS) in the implementation of RRT algorithm, a novel strategy for searching the nearest neighbor is developed, i.e., Generalized Distance Method and Cell Method. Both methods are tested in simulation-based experiments. The results show that 1) the Generalized distance method not only reduces the search time, but also unifies the unit of distance measurement and clarifies the physical meaning of distance; 2) the Cell method dramatically reduces the traversal range as well as the search time; and 3) both methods improve the quality of lifting path planning of mobile cranes. This improved RRT algorithm enables rapid path planning of mobile cranes in a dynamic and complex construction environment. The outcomes of this research not only contribute to the body of knowledge in spatial path planning of crane lifting operations, but also have the potential of significantly improving efficiency and safety in crane lifting practices.

Automation and optimization in crane lift planning: A critical review

Safe and efficient crane operations play a significant role in successful delivery of construction projects, and thus meticulous planning of crane lifts becomes increasingly critical. Crane lift planning involves a series of complex decisions to be made, while satisfying a wide range of criteria and constraints. Conventionally, making these decisions is time-consuming and to a large extent relies on the planner’s experience. To make more informed and optimized planning decisions, past research works investigated various automated planning techniques and optimization algorithms. However, most studies focus on an individual planning decision or a particular lifting scenario, which makes the findings hard to be generalized. Thus, the knowledge in lift planning is rather fragmented and the state-of-the-art in lift planning is not explicitly presented. This study, therefore, aims to conduct a critical review and assessment on the literature on crane lift planning automation and optimization and to establish a solid foundation to inform future research. It first presents an overview of the literature in crane lift planning with respect to the planning decision and the type of cranes the studies focus on. Secondly, for each lift planning decision, the assumptions, objectives, decision variables, and constraints are formulated based on the literature and analyzed from the perspectives of problem formulation coherence. Furthermore, each problem-solving method is evaluated with regard to a tri-axial evaluation diagram to allow an in-depth discussion on the efficacy and practicality of planning results. Finally, based on the discussion and existing literature, a BIM-based lift planning framework is presented and future research directions are recommended to further improve the effectiveness and efficiency of lift planning practice.

Eye movements in real and simulated driving and navigation control - Foreword to the Special Issue.

The control of technological systems by human operators has been the object of study for many decades. The increasing complexity in the digital age has made the optimization of the interaction between system and human operator particularly necessary. In the present thematic issue, ten exemplary articles are presented, ranging from observational field studies to experimental work in highly complex navigation simulators. For the human operator, the processes of attention play a crucial role, which are captured in the contributions listed in this thematic issue by eye-tracking devices.For many decades, eye tracking during car driving has been investigated extensively (e.g. 6; 5). In the present special issue, Cvahte Ojsteršek & Topolšek (4) provide a literature review and scientometric analysis of 139 eye-tracking studies investigating driver distraction. For future studies, the authors recommend a wider variety of distractor stimuli, a larger number of tested participants, and an increasing interdisciplinarity of researchers.In addition to most studies investigating bottom-up processes of covered attention, Tuhkanen, Pekkanen, Lehtonen & Lappi (10) include the experimental control of top-down processes of overt attention in an active visuomotor steering task. The results indicate a bottom-up process of biasing the optic flow of the stimulus input in interaction with the top-down saccade planning induced by the steering task.An expanding area of technological development involves autonomous driving where actions of the human operator directly interact with the programmed reactions of the vehicle. Autonomous driving requires, however, a broader exploration of the entire visual input and less gaze directed towards the road centre. Schnebelen, Charron & Mars (9) conducted experimental research in this area and concluded that gaze dynamics played the most important role in distinguishing between manual and automated driving.Through a combination of advanced gaze tracking systems with the latest vehicle environment sensors, Bickerdt, Wendland, Geisler, Sonnenberg & Kasneci (2021) conducted a study with 50 participants in a driving simulator and propose a novel way to determine perceptual limits which are applicable to realistic driving scenarios.Eye-Computer-Interaction (ECI) is an interactive method of directly controlling a technological device by means of ocular parameters. In this context, Niu, Gao, Xue, Zhang & Yang (8) conducted two experiments to explore the optimum target size and gaze-triggering dwell time in ECI. Their results have an exemplary application value for future interface design.Aircraft training and pilot selection is commonly performed on simulators. This makes it possible to study human capabilities and their limitation in interaction with the simulated technological system. Based on their methodological developments and experimental results, Vlačić, Knežević, Mandal, Rođenkov & Vitsas (11) propose a network approach with three target measures describing the individual saccade strategy of the participants in this study.In their analysis of the cognitive load of pilots, Babu, Jeevitha Shree, Prabhakar, Saluja, Pashilkar & Biswas (3) investigated the ocular parameters of 14 pilots in a simulator and during test flights in an aircraft during air to ground attack training. Their results showed that ocular parameters are significantly different in different flying conditions and significantly correlate with altitude gradients during air to ground dive training tasks.In maritime training the use of simulations is per international regulations mandatory. Mao, Hildre & Zhang (7) performed a study of crane lifting and compared novice and expert operators. Similarities and dissimilarities of eye behavior between novice and expert are outlined and discussed.The study of Atik & Arslan (2) involves capturing and analyzing eye movement data of ship officers with sea experience in simulation exercises for assessing competency. Significant differences were found between electronic navigation competencies of expert and novice ship officers. The authors demonstrate that the eye tracking technology is a valuable tool for the assessment of electronic navigation competency.The focus of the study by Atik (1) is the assessment and training of situational awareness of ship officers in naval Bridge Resource Management. The study shows that eye tracking provides the assessor with important novel data in simulator based maritime training, such as focus of attention, which is a decisive factor for the effectiveness of Bridge Resource Management training.The research presented in the different articles of this special thematic issue cover many different areas of application and involve specialists from different fields, but they converge on repeated demonstrations of the usefulness of measuring attentional processes by eye movements or using gaze parameters for controlling complex technological devices. Together, they share the common goal of improving the potential and safety of technology in the digital age by fitting it to human capabilities and limitations.

Selection of a rational algorithm for data processing of the weight measuring system of a hoisting crane

The paper deals with the choice of the algorithm for processing the data of the load sensor of the crane weight measuring system being developed. The requirements for the weight measuring system are based on the operating conditions of the crane (the nature of the dynamic process, the limitation of the weighing time) and the planned use of information about the weight of goods (the required accuracy). A comparison of 5 signal processing algorithms is presented: direct averaging, search for extremes with two different modes of pre-smoothing, nonlinear regression, and averaging using a short-term memory buffer. A series of experiments was conducted to compare the methods. The data was obtained on the KMG-201 bridge crane. Based on the results of numerical evaluation of the results of experimental data processing, conclusions are drawn about the applicability of the considered algorithms for analyzing the dynamic process of the crane lifting mechanism. The algorithms for finding extremes, regardless of the pre-smoothing modes, did not show the required accuracy (the relative error was 5%). The averaging algorithm using a short-term memory buffer showed the highest accuracy (the relative error was 1%). The influence of the parameters of the data reception board on the result of the algorithms is estimated. The parameters varied in the range: bit depth 10-12 bits, sensor polling frequency 4.1-256 Hz. Most experiments showed an increase in accuracy with increasing bit depth. Also, according to the results of the experiments, it was found that an increase in the sensor polling frequency of more than 64 Hz in the conditions of this dynamic process does not affect the accuracy of determining the weight of the load. The study showed the need for further work in the direction of determining the optimal parameters of the averaging algorithm with a short-term memory buffer and determining the limit of increasing accuracy with increasing the bit depth of the data reception board.

A practicality and safety-oriented approach for path planning in crane lifts

Safe and efficient operations of cranes in complex construction environments require thorough planning of lift paths. As the scales of construction projects expand, path planning becomes excessively sophisticated and laborious using conventional practices where lift paths are verified manually. This study proposes a novel practicality and safety-aware path planning method for single crane lifting scenarios, which defines and incorporates key practicality considerations in a sampling-based path planning algorithm. An RRT*-based algorithm is proposed and validated via a case study of real-world lift jobs. Results indicate that the proposed method significantly improved the path quality in terms of practicality considerations without compromising computational efficiency. The proposed method is promising in generating operable and realistic paths that can be practically executed by crane operators. It is expected to advance the knowledge and practice in automated crane lift planning, allowing for more informed prediction and management of on-site activities involving the use of cranes.

A Hybrid Iterated Greedy Algorithm for a Crane Transportation Flexible Job Shop Problem

In this study, we propose an efficient optimization algorithm that is a hybrid of the iterated greedy and simulated annealing algorithms (hereinafter, referred to as IGSA) to solve the flexible job shop scheduling problem with crane transportation processes (CFJSP). Two objectives are simultaneously considered, namely, the minimization of the maximum completion time and the energy consumptions during machine processing and crane transportation. Different from the methods in the literature, crane lift operations have been investigated for the first time to consider the processing time and energy consumptions involved during the crane lift process. The IGSA algorithm is then developed to solve the CFJSPs considered. In the proposed IGSA algorithm, first, each solution is represented by a 2-D vector, where one vector represents the scheduling sequence and the other vector shows the assignment of machines. Subsequently, an improved construction heuristic considering the problem features is proposed, which can decrease the number of replicated insertion positions for the destruction operations. Furthermore, to balance the exploration abilities and time complexity of the proposed algorithm, a problem-specific exploration heuristic is developed. Finally, a set of randomly generated instances based on realistic industrial processes is tested. Through comprehensive computational comparisons and statistical analyses, the highly effective performance of the proposed algorithm is favorably compared against several efficient algorithms. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Note to Practitioners</i> —The flexible job shop scheduling problem (FJSP) can be extended and applied to many types of practical manufacturing processes. Many realistic production processes should consider the transportation procedures, especially for the limited crane resources and energy consumptions during the transportation operations. This study models a realistic production process as an FJSP with crane transportation, wherein two objectives, namely, the makespan and energy consumptions, are to be simultaneously minimized. This study first considers the height of the processing machines, and therefore, the crane lift operations and lift energy consumptions are investigated. A hybrid iterated greedy algorithm is proposed for solving the problem considered, and several problem-specific heuristics are embedded to balance the exploration and exploitation abilities of the proposed algorithm. In addition, the proposed algorithm can be generalized to solve other types of scheduling problems with crane transportations.

Evaluation of Wave-induced Coupled Dynamics Between Multi-purpose Offshore Supply Vessel and Suspended Load During Crane Lifting Operation

As crane lifting operation in ocean is vital to construct offshore structures and install subsea facilities on the seafloor, evaluation of safety and availability for the crane lifting operation is needed before the construction. For these analyses, it's fundamental to predict wave-induced coupled dynamics between a vessel and a suspended load. The coupled dynamics makes the each mechanics more complex. In the case of using the multi purpose offshore supply vessel to the crane lifting operation, deep understanding about the mechanics is required because it offers various crane operations. In our previous paper, we propsed the numerical method to estimate the swirling of the suspended load in air and considered the impact of the suspended load's location on the coupled dynamics using the both numerical calculation and estimation method. To expand our knowledge and numerical method for the crane operation, we inestigated the coupled dynamics right after the suspended load entry into the sea surface. In such the situation, it's possible that the hydrodynamics on the suspended load change the coupled dynamics and produce unexpected risk for the crane lifting operation. In this paper both experiments and numerical simulation we conducted are shown to consider the coupled dynamics between the vessel and the suspended load. Furthermore we indicated the results of sensitivity analysis by numerical simulation to put the point of focus on the natural period of the vessel's roll motion. As results, we made clear the inversion of the natural period could be occured depending on where the location of the suspended load is.

Crane Lifting Optimization and Construction Monitoring in Steel Bridge Construction Project Based on BIM and UAV

Modular construction methods are adopted in many spatial and temporal limited projects. As the major equipment used in modular construction, the mobile crane affects the safety and efficiency of construction significantly. Currently, building information modeling (BIM) is widely adopted to improve the lifting operation planning of cranes. However, the inaccurate simulation of the dynamic construction environment makes those BIM‐based lifting operation planning methods unsuitable for land mobile cranes operation planning, such as in the overpass bridge construction project, which may cause several safety risks during the lifting process. Based on an overpass steel bridge construction project, this paper attempted to integrate the BIM and unmanned aerial vehicles (UAVs) to streamline lifting operation planning and construction monitoring. Specifically, in the preliminary stage, a level of development (LOD) 400 steel superstructure model was built and then divided into eighty sections. In addition, a three‐dimensional (3D) geology model of the as‐is construction site was modeled by UAV‐captured images. Then, a fusion model which contains the lifting modules models, the as‐is site model, and the crane model was gathered, based on which the collision detection was conducted by 4D crane operating path simulation. According to the results, three potential collisions were found and eliminated by lengthening the jib of the crane from 43.5 m to 46.5 m. Furthermore, the optimum crane location for lifting each steel structure was determined based on the 3D geology model. The study shows that the UAV is able to acquire geological information and then 3D simulates the real construction environment quickly and accurately. Furthermore, BIM and UAV have the potential to optimize the design and construction as well as the monitoring of bridge projects.

Image-based onsite object recognition for automatic crane lifting tasks

The construction industry is suffering from aging workers and frequent accidents, as well as low productivity. Automation and robotics is regarded as a promising approach for enhancing the development of the industry, and the automatic operation of cranes, as an important aspect of construction, is attracting increasing attention. However, due to the complexity and dynamics of construction sites, it is difficult for cranes to automatically recognize and locate lifting objects (e.g., precast facades and partitions) on site. To solve this problem, an image-based automated onsite object recognition approach for the automatic operation of cranes is developed in this study. This is a fusion of Faster-R-CNN (Region-based Convolutional Neural Network), Canny, Hough Transformation, Endpoint clustering analysis and Vertex-based Determining Model, to uniquely locate a lifting object with exact pose and extract its features (e.g., centroid coordinates, size, and color). Based on the extracted features, the lifting object can be retrieved in the database with the IFC (Industry Foundation Classes) format of BIM (Building Information Modeling) to obtain more features for the automatic operation of a crane. It is shown from a field experiment that the developed approach is workable and has the potential to support the automatic operation of cranes. This contributes a basic approach to the automatic operation of cranes and promotes the rapid development of construction automation and robotics.

Heavy mobile crane lift path planning in congested modular industrial plants using a robotics approach

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.

An A-Star algorithm for semi-optimization of crane location and configuration in modular construction

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.

Experiments With a Rotor-Hybrid Gas Bearing System Undergoing Maneuver Loads From Its Base Support

Abstract Gas bearings enable microturbomachinery (MTM) with a large power to weight ratio, low part count, and nearly frictionless motion, thus resulting in systems operating over extended maintenance intervals and with improved fuel efficiency. Envisioned oil-free vehicle transportation systems implementing gas bearings range from small size gas turbines, to unmanned aerial vehicles, to turbochargers (TC), and more to come. In these vehicles, base or support transient displacements transmit forces exciting the rotor-bearing system; hence, the need to characterize system integrity under stringent operating conditions. This paper reports experiments demonstrating the ability of a hybrid gas bearing-rotor system to withstand maneuver actions that suddenly remove the ground support. The test rig consists of a rigid motor-rotor, supported on tilting pad hybrid gas bearings supplied with pressurized air. The rotor is housed in a thick steel casing that is attached to a rigid base plate. The whole test rig hangs from a crane; two steel cables connect to one side of the base and a nylon webbing attaches to the other side of the base. The other end of the webbing ties to a release mechanism, which when released, frees one side of the rig base. Suddenly, the whole test rig rotates and displaces downward while the tensions in the taut cables rapidly increase and pull the test rig as it swings back and forth. The crane support enables two release maneuvers: one turns the rig ∼90 deg and the other flips it 180 deg, both events occurring while the rotor spins at 70 krpm (surface speed 105 m/s). The measured rotor displacements relative to the casing demonstrate a momentary increase in motion amplitude, up to ∼1.15 mm since the bearings also displace, along with a maximum casing deceleration of ∼7 g when the cables stop the rig fall. The measurements show the rotor response is free of subsynchronous whirl frequencies that could evidence a rotor dynamic instability. Very low frequency motions denote the swing frequency of the hanging rig and jerk motions from the crane lifting and bouncing when the rig is at its lowest vertical position. In one instance, power to the motor unexpectedly interrupted and the rotor underwent an unplanned shaft speed coastdown. In spite of the large displacements recorded, the rotor survived both events; it continues to operate to this day. The experiments demonstrate that the hybrid gas bearing system could withstand large amplitude rotor excursions. The measurements provide a novel method for testing gas bearings, as the induced excitations are multidirectional, while the test rig encounters a short period of free falling, followed by a quick deceleration with large forces. A simple kinetics model of the test rig drop produces peak decelerations similar in magnitude to those measured.

The Multi-Spreader Crane Scheduling Problem: Partitions and supersequences

In the Multi-Spreader Crane Scheduling Problem (MSCSP), containers with identical dimensions but variable weights are arranged along a grid. A multi-spreader crane is used to lift all the containers. The crane has m>1 modes. When it is in the pth mode, the crane can remove p adjacent containers along the same row at the same time as long as the total weight of the containers does not exceed the loading capacity κp. Such a lift takes hp minutes. It also takes cp,q minutes for the crane to switch from mode p to q when p≠q. The goal is to find a crane lift sequence so that the total time it takes to lift all the containers is minimized.This paper investigates the computational complexity of MSCSP. First, we establish a connection between greedy crane lift sequences and supersequences. We then prove that MSCSP is NP-hard when the crane has three or more modes by a reduction from a version of the Shortest Common Supersequence problem. Lastly, we investigate two problems that arise naturally when heuristics are used to solve MSCSP. We show that one can be solved using dynamic programming while the other remains computationally hard. We also provide an approximation algorithm that behaves nicely when the changeover times are not much larger than the lifting times of the crane.

Теоретическое обоснование и моделирование устройства подъема крана

Теоретическое обоснование и моделирование устройства подъема крана

Rigid Dynamic Load of the Crane Lifting Mechanism When the Series Resistance Starts

With the development of economy, industry and manufacturing industry play an important role in China’s economy. As the most extensive machinery in the industry and manufacturing industry, the development of crane will inevitably affect the development of the whole industry, so how to improve the performance of crane and how to carry out a wide range of analysis has become the current problem to be solved. Starting from the crane, this paper focuses on the study of the rigid dynamic load coefficient when the series resistance of the lifting mechanism of the crane starts, and analyzes the influence of these coefficients on the performance of the crane. In this paper, the big data analysis method is put forward firstly, and the change of rigid dynamic load coefficient when the chain resistance of crane hoisting mechanism starts in China’s industry and manufacturing industry in the past 10 years is analyzed. Secondly, the concept and classification of crane are briefly summarized. The crane is mainly divided into two types, one is tire crane, the other is bridge crane. Then this paper establishes the system model and the mathematical model of the crane lifting transmission system. Through the analysis of the system model, we can get the relationship between the rigid dynamic load coefficient α and φ, and the relationship between β and φ. Their relationship is that the growth rate of the rigid dynamic load is slowed down after α is greater than 5, and the starting torque multiple and the rigid dynamic load coefficient are linear.

Multi crane lift simulation using Building Information Modeling

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.

Critical lifting simulation of heavy industrial construction in gaming environment

PurposeHeavy industrial construction often relies on large mobile cranes to erect equipment and pre-assembled modules. Engineering calculations are required for the lifting analysis where lifting capacity is analyzed to ensure the feasibility of the lifting scenarios. Such engineering calculations are often presented in static formats, e.g. two-dimensional or three-dimensional models. However, it is difficult to help practitioners (e.g. lifting engineers, site crews and operators) understand the complexity of the lifting process and thus operational decisions are often made intuitively. Therefore, this paper aims to introduce a game-based simulation system to allow for interactive analysis of the lifting process to improve lifting efficiency and safety.Design/methodology/approachThe proposed method treats the mobile crane as a robot with degree-of-freedoms, and the movements are simulated in the Unity game environment. The lifting capacity is calculated dynamically based on the lifting object weight, rigging weight and lifting radius.FindingsCompared with the four-dimensional visualization, this development has added a dimension of real-time interactive simulation; this allows the users to understand the complexity and feasibility of the lifting process.Originality/valueThe developed prototype has been tested and validated using a real case study from a heavy industrial project with the possibility of generalizing crane lifting configurations.