Interactive and Dynamic Integrated Module for Mobile Cranes Supporting System Design

Analyzing and designing a crane supporting system can be time-consuming process. In particular, the dynamic nature of mobile crane operations entails a variety of reaction values for truck and crawler cranes. The platform of a mobile crane can either be set on outriggers—denoted as a truck crane, or on a crawler tracks—denoted as a crawler crane. Designing of a mobile crane supporting system depends on the lifting configuration, type of crane and the type of materials to be used under the crane outriggers or crawler tracks. This paper presents an automated system which is designed to assist practitioners in calculating the mobile crane’s support reactions and in designing the supporting system. This system is developed such that it can generate a 2D reaction influence chart which shows the reactions for each outrigger at varying horizontal swing angles and vertical boom angles to the ground. Most of the geometric configurations needed to perform the support design are not ordinarily given in crane manufacturer’s manual and to address this deficiency, this newly developed system has been integrated with a previously developed crane database which contains information on widely used mobile cranes for construction along with a crane selection system. A case example is described in order to demonstrate the use and effectiveness of the presented system in automating crane lift analysis.     

Automated Path Planning of Cooperative Crane Lifts Using Heuristic Search

The use of cooperative cranes can improve the cost effectiveness of heavy lift operations. However, the complexity in developing a reliable lift plan prevents the widespread use of cooperative crane lifts. The availability of a computer-aided planning system can improve planning efficiency and reliability. Path planning is an important subtask of the lift planning process. This paper presents work done to develop a computer aided path planner for two crane lifts. Two heuristic search methods, hill climbing and A?, were implemented for automating the path-planning task. Search space was represented using the concept of configuration space. The effectiveness of the search methods was evaluated by solving three problems with increasing levels of complexity. The formulation of these problems was based on the type of movement of cooperative cranes (in synchronous or asynchronous manner) and the presence of trapping space. It was found that while the hill climbing approach found feasible paths in a few seconds or minutes, these paths were far from optimal in situations containing trapping space. In contrast, the A? search resulted in near optimal paths, but the execution time was of the order of hours.     

Optimization Algorithm for Selection and on Site Location of Mobile Cranes

Mobile crane manufacturers provide operators and practitioners with tabulated lift-capacity charts. These charts are structured based on predetermined crane configurations, which consist of boom/jib length, lifting radius, lifting height, main boom angles to ground, and jib angle to ground or its offset to its main boom centerline. Practitioners, however, are often required to lift on a partially extended hydraulic section and/or lifting radius other than those listed in the manufacturers’ lift-capacity charts. This paper presents a newly developed optimization algorithm (referred to in this paper as Algorithm-2) for selecting and locating mobile cranes on construction sites based on their minimum boom length and/or minimum radius, accordingly higher lifting capacities. Algorithm-2 includes an optimization procedure that avoids lifting capacity violations. In addition to the practical use of Algorithm 2, the mathematical representations of the crane’s geometry are also useful for research in the automation and robotic field of operations involving cranes. The algorithm is incorporated into a computer system that integrates a selection module and a database. Data pertinent to crane lift configurations are retrieved from the database and are then processed to determine the optimum, geometrical selection of the crane configuration. A case example is described in order to demonstrate the use of the developed algorithm and to illustrate its essential features.     

Simulation-Based Identification of Possible Locations for Mobile Cranes on Construction Sites

Identifying spatial-conflict free locations of mobile cranes that could minimize delays associated with crane relocation can result in productivity and safety improvements on construction sites. Existing approaches for identifying possible crane locations are based on two-dimensional (2D) work envelopes created by reasoning about the lift capacities of a crane during operations. Since spatial conflicts related to crane operations typically occur in three dimensions and during any period of operation, representing possible crane locations based on such 2D work envelopes can result in identifying some locations as good when in fact they might result in conflicts and missing possible locations that might be feasible. This paper presents an approach that determines possible locations of mobile cranes based on discrete-event simulation of crane operations incorporating dynamic behaviors of cranes. This approach starts with identifying a search space for possible crane locations by reasoning about a reachability radius of a crane determined by crane characteristics and the weight of the load to be carried. Later, it reduces the search space through boom-line intersection tests. For the remaining locations, it checks for potential spatial conflicts between building components and cranes moving in three dimensions and across time. Validation studies show that the developed approach can accurately identify possible locations for mobile cranes that minimize the relocation of mobile cranes and avoid potential spatial conflicts.     

Algorithm of Crane Selection for Heavy Lifts

Lifting capacity charts are tabulated and provided to operators and practitioners by mobile crane manufacturers. These charts are structured based on predetermined crane configurations, which consist of boom/jib length, lifting radius, main boom angle to ground, and jib angle to ground or its offset to its main boom centerline. It is a tedious job that lifting planners select cranes for construction projects based on a large number of lifting capacity charts. This paper presents a newly developed algorithm for selecting mobile cranes on construction sites, which takes into account the lifting capacity, the geometrical characteristics of the crane, the dimensions of equipments and riggings, and the ground bearing pressure. The algorithm is incorporated into a three-dimensional (3D) computer-aided system that integrates crane selection module, crane modeling module, 3D-simulation module, 3D computer-aided design modeling module, rigging calculation module, and data management module. At last, a case is represented in order to demonstrate the use of the developed algorithm and to illustrate its essential features.     

Lampson Transi-Lift Mobile Crane: Concept, Design, and Use

The Lampson Transi-Lift mobile crane is a lifting system purposely designed for construction activities related initially to nuclear power facilities. The combination of capacity, increased working hook height, and an unmatched radius to capacity ratio allowed for use of innovative construction techniques that decreased the construction schedule, increased facility integrity and construction safety, and reduced overall plant construction costs. The versatility of the Lampson Transi-Lift was immediately recognized, and it has become a mainstay of the heavy lift industry since its introduction in the late 1970s. Oil and gas, general construction, and offshore construction activities have all since benefitted from the unique capabilities of this heavy lift crane     

Vision System for Tower Cranes

Operators of tower cranes enjoy a bird’s eye view of the site, which undeniably contributes to work safety and efficiency. Yet their work often involves blind lifts, as well as other viewing difficulties, that impede full utilization of the potential inherent in the operator’s location atop the crane. This paper reports on a tower-crane-mounted live video system that offers a solution for such difficulties, and consequently, enhances safety, improves productivity, and brings about direct and indirect cost savings. The development and implementation of the vision system are described as a successful academia–industry research and development joint effort. Work studies of numerous craning cycles resulted in considerable time savings, depending on the nature of the lift, lighting conditions, and viewing obstructions. In addition, a detailed list of benefits drawn on the basis of feedback received from the field is presented. The paper is aimed, first and foremost, at project managers as well as construction equipment and safety practitioners, who daily experience those situations that have prompted the development of the system. Researchers may benefit mainly from the lessons learned with respect to the role of academia–industry cooperation in the introduction of innovative systems in construction.     

Adaptive Probabilistic Neural Network-based Crane Type Selection System

Due to the central role of cranes in construction operations, specialists in the construction industries have cooperated in the development of structured methods and software for crane selection. Most of these software tools are for crane model selection, and integrated systems that handle both crane type and model selection are not readily available. This paper presents the crane type selection features of IntelliCranes, a prototype integrated crane selection tool that assists in both crane type and crane model selection based on a set of inputs describing the construction operation under consideration. By using historical data and advanced artificial intelligence computing tools such as artificial neural networks, IntelliCranes automates crane type selection. Crane type and crane model selection are seamlessly integrated in a comprehensive crane selection tool, and consistency in the selection of cranes for similar situations is increased.     

Crane-Related Fatalities in the Construction Industry

One of the major causes of fatalities during construction is the use of cranes or derricks during lifting operations. Using the Occupational Safety and Health Administration’s (OSHA) case files from fatality investigations during the years 1997–2003, the writers examined the data to determine the proximal causes and contributing physical factors. The research results showed the use of mobile cranes with lattice and telescopic booms, truck or crawler mounted, represented over 84% of the fatalities in the use of cranes/derricks. To reduce the rate of crane fatalities the writers believe that crane operators and riggers should be qualified and requalification should occur every 3?years. Crane safety training must be provided to specialty trade crafts before they are allowed to work around cranes during lifting operations. In addition, a “diligent” competent person [as defined in 29CFR 1926.32(f)] should be in charge of all aspects of lifting operations. Finally, OSHA should improve its system of collecting information during fatality investigations, placing emphasis on intervention strategies to improve usefulness of the investigations to researchers and policymakers inside and outside the Agency.     

Cranes for Building Construction Projects

Cranes have come to symbolize building construction itself. They perform indispensable services in moving materials and components vertically and horizontally. Used since antiquity, their history is interrelated with the development of new power sources that replaced man and mule, first steam and later internal combustion, diesel, and electric engines. Mobile cranes can be rapidly deployed to lift heavy loads. New models with telescoping booms and all-terrain travel capability, compact urban machines, and even hybrids with tower cranes are beginning to replace the familiar lattice boom truck cranes. Mobile cranes have dominated the North American market, but a cultural change appears to be taking place toward tower cranes for building projects. Tower cranes, common in Europe for decades, are globally gaining in popularity with surging real estate developments. Ideal for dense urban environments and coming with a small footprint, they are available in a growing diversity of sizes and configurations. Sophisticated electronic controls and operator assistance devices are enhancing their safe and productive operation. While cranes occupy a central role on midrise and high-rise building projects, they operate in conjunction with other types of supporting equipment that are an essential part of the overall equipment array on today’s industrialized construction sites.     

Analyses of Instability in Mobile Cranes due to Ground Penetration by Outriggers

This study focuses on the phenomenon of ground instability causing mobile cranes to overturn. Four outriggers usually support a mobile crane in order to restrict pitching during hoisting operations. Nevertheless, the crane may become quite unstable if the outriggers should happen to sink into the bearing ground. In this paper, various types of analysis, including experiments, were performed in order to investigate the influence of ground penetration by outriggers on the stability of mobile cranes. Through study of the results of experimentation and simulation, it has been clarified that mobile cranes become highly unstable as a result of rapid penetration. It was found that an index of relative instability had a linear relationship to the common logarithm of an index for brittle failure as derived from the load–settlement curve for ground penetration. Finally, a method of evaluating the risk of mobile-crane overturning is proposed by using the maximum value of both the supporting surface’s failure risk and the kinetic risk due to ground penetration.     

Computational Methods for Coordinating Multiple Construction Cranes

The incremental coordination method a computational method for preplanning and coordinating the use of multiple tower cranes in relatively narrow construction sites is presented. The incremental coordination method considers the kinematics and the geometrical constraints of cranes to plan the motion of two or more cranes, which are being operated in collaboration. By following such planned motions, erection tasks are completed safely, even when the cranes are operated in close proximity of each other. This method allows the use of computers to plan and coordinate the crane activities from start to end of an erection process. This paper also explains the computational methods required by the incremental coordinate method including path-finding and collision detecting methods. An example case shows two construction cranes, each of three degrees-of-freedom, operating together on a building project where the working areas of the cranes intersect, hence possibility colliding with each other. A numerical test was conducted to verify the efficiency and effectiveness of applying the incremental coordination method in planning and synchronizing all motions of the two cranes to avoid any collision between the cranes themselves and collision with obstacles on the construction site.     

Dynamic Analysis of Tower Cranes

Tower cranes are widely used in the construction of high-rise buildings and the analysis of their dynamic behaviors is of both theoretical and practical significance. A parameterized super element formulation for modeling the multiple-pulley cables in a crane system is proposed based on the friction-free assumption between the cable and pulleys. The cable passages over intermediate pulleys are considered as new degrees-of-freedom in the proposed element model and equal tensions at different segments of a continuous cable are exactly achieved. Numerical results show that these cable passages have significant effect on both static tensions and dynamic properties of tower cranes and the proposed super element model provides more accurate and realistic results in dynamic analyses of the crane system. It is found that some modes are insensitive to the change of jib angle or bracings at crane mast, while others change drastically depending on the mode shapes. Picking up the payload from ground or payload accelerating/decelerating during lift operation will induce finite impulsive excitations and, therefore causes noticeable dynamic responses of the crane system.     

Measurement and Risk Scales of Crane-Related Safety Factors on Construction Sites

This paper addresses quantitative measurement and risk scales of safety hazards on construction sites due to the work of tower cranes. Hazard measurement and risk scales are essential components of an integrated model aimed at quantitatively determining the safety level of individual construction sites, on a comparative basis. The paper focuses on two factors identified in earlier studies as considerably affecting safety on sites with tower cranes, “overlapping cranes” and “operator proficiency.” These two factors are inherently different from each other in their characteristics and therefore also in the methods used to measure both the factors and the risk resulting from them. A probability-based method was prescribed for the measurement of overlapping cranes, while the analytical hierarchy process method and knowledge elicitation from experts were applied to develop metrics for operator proficiency. In both cases, an intimate understanding of the crane work environment is necessary. The uniform format and specific methodologies presented here can be used in the development of measurement techniques and risk scales for other safety factors concerning crane operation on construction sites.     

Collision Free Path Planning of Cooperative Crane Manipulators Using Genetic Algorithm

This paper presents a new approach for automated path planning of cooperative crane manipulators using a genetic algorithm (GA). The inverse kinematic problem, i.e., determining the joint angle configuration for the cooperative crane manipulator system in moving the object from pick location to place location, is defined as an optimization problem and solved using GA. For generating the collision-free path, GA with an interference detection algorithm is employed and search is made in the manipulator joint angle space (configuration space). The effectiveness of the proposed approach for automated path planning is demonstrated by comparing the performance of the present approach with the earlier heuristic search proposed by Sivakumar et al. The GA approach finds a near-optimal path with lower path cost and less computational time than earlier heuristic searches.     

Constructing a Complex Precast Tilt-Up-Panel Structure Utilizing an Optimization Model, 3D CAD, and Animation

This paper presents the concept used to construct a complex residential tilt-up-panel structure utilizing three-dimensional (3D) modeling and animations. The residence comprises of 108 precast concrete panels of varying rectangular shapes with “dog legs” and window and door “cutouts” that look like an assembled jigsaw puzzle. The erection and installation procedure called for a maximum panel-to-panel joint tolerance of 1.27?cm (0.5?in.), often in 90° joints between panels. 3D animations were used to experiment with the construction process on the computer screen prior to construction in order to avoid potential costly on-site errors. In addition, the 3D animations were also used as a training tool for the contractors. This paper focuses on describing the methodology used to integrate a crane selection algorithm and optimization model with 3D modeling and animation for the selection, utilization, and location of cranes on construction sites. Analytical optimization processes were used to decrease the traveling time and distance of the selected crane, to improve the crane lifting sequence and to minimize the use of panel casting slabs.     

AHP-Based Weighting of Factors Affecting Safety on Construction Sites with Tower Cranes

Aspiring to adopt a nonstatistical quantitative approach to safety assessment, this study implements a multiattribute decision-making tool to elicit knowledge from experts and formalize it into a set of weighted safety factors. The environment addressed is the construction site and the specific factors studied are those affecting safety due to the operation of tower cranes. Nineteen senior construction equipment and safety experts were interviewed and led through the analytic hierarchy process (AHP) to provide their assessments on the relative importance of safety factors obtained in an earlier study. The results accentuate the dominance of the crane operator and general superintendent on the site safety scene and play down the contribution of “classic” site hazards such as power lines. Quantitative measuring of safety, such as reflected in the weights obtained in this study, is important in communicating safety requirements and focusing the limited resources available for safety improvements. These factor weights are also deemed to be a vital component in the development of a comprehensive model that will allow the computation of safety indices for individual construction sites employing tower cranes. It is expected that the methodology can then be adopted for addressing other site safety issues as well.     

Achieving Construction Innovation through Academia-Industry Cooperation—Keys to Success

The conception, development, implementation, and commercialization of a crane-mounted vision system through close academia-industry cooperation illustrate how such joint efforts can yield research and development success. The vision system was devised to help solve the problem of blind lifts and other viewing concerns related to the operation of tower cranes on construction sites, thereby enhancing safety and productivity and saving money. In addition to other expected difficulties, the project faced the traditional skepticism of a conservative industry reluctant to adopt changes. The paper relays the chronology of the project and analyzes, stage by stage, the steps taken by the university-based developers to work in harmony with construction companies in particular, and with the industry at large, to ensure success. Lessons drawn from this experience are offered to future academician developers in the field of construction technology.     

Interactive 3D CAD for Effective Derrick Crane Operation in a Cable-Stayed Bridge Construction

The high expectation of esthetic and functional quality in modern civil infrastructure has resulted in the increased demand for long span bridges. In advanced or developing countries, long span bridges such as cable-stayed and suspension bridges are considered even as landmarks that symbolize the prosperity or culture of the region. These long span bridges require higher level of design and construction technologies than other types of bridges. In particular, the construction of cable-stayed bridges involves precise and sophisticated operation of construction equipment such as derrick cranes. However, it is not easy to plan the operations of a derrick crane before the actual construction process takes place. Unexpected spatial constraints in the construction site may hinder the smooth operation of a derrick crane, which leads to lower than expected productivity and safety. This study applies interactive three-dimensional (3D) computer aided design (CAD) to the derrick crane operation for the purpose of identifying potential problems. Construction managers can have the two way process with the 3D CAD system to interactively test their construction plans and scenarios. The case study shows that the interactive 3D CAD system significantly improves the constructability of the cable-stayed bridge construction.