Innovative System for Off-the-Ground Rotation of Long Objects Using Mobile Cranes

Managing heavy-pressure vessel lifts on construction sites requires planning, arranging adequate crane support, and preparing collision-free rotation (from a horizontal position to a vertical position) of the vessel. Generally, selecting mobile cranes and developing engineered lift studies for vessels are done using two cranes and analyzing the lift for each crane individually on the basis of the selected cranes’ lift-capacity specifications provided by crane manufactures. This practice is relatively costly and time-consuming. Optimizing the mobile cranes’ use and location is also difficult. To assist in the field operation of mobile cranes and to provide engineers with a planning tool, this paper presents a methodology to carry out such a lift utilizing only one crane. Using the developed methodology and mechanism, heavy vessels can be rotated off the ground (in the air) with one crane. The proposed mechanism is supported with a mathematical model that has been developed into a computer system and has been integrated with a previously developed crane selection and ground pressure calculation system and crane database. The developed system provides users with a lift study analysis for a given configuration as well as simulation results with interactive graphics to assist in the selection of an optimum configuration. This research is important as projects involving heavy lifts need to reduce the cost and time associated with construction operations.     

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.     

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.     

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     

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.     

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.     

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.     

Performance Evaluating Model for Construction Companies: Egyptian Case Study

The dynamic nature of today’s construction industry compels construction partners to seek strategies in order to improve performance. Current research introduces a performance evaluation model for construction companies in order to provide a proper tool for a company’s managers, owners, shareholders, and funding agencies to evaluate the performance of construction companies. The model developed helps a company’s management to make the right decisions. Financial, economical, and industrial data are collected from Egyptian construction companies for nine consecutive years (1992–2000). Five indices (models) are developed: company performance score, economy performance score, industry performance score, performance index, and performance grade. The models developed consider companies in four construction sectors: general building, heavy, special trade, and real estate. These models accommodate the effect of macroeconomic and industry related factors and company size on the performance evaluation. The final outcome of current research is a performance grade, which provides the performance of a construction company. The developed model is validated, which shows robust results.     

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.     

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.     

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.     

Nonlinear Models for Predicting Hoisting Times of Tower Cranes

Accuracy in estimating activity duration is one of the key prerequisites for successful construction planning. Efficient material transportation plays an important role in reducing costs and time. Time measurement and work-study techniques can provide good estimation of activity duration, but forming the databank for various conditions is expensive. The use of empirical models has been developed as an alternative to overcome the deficiency while maintaining a reasonable accuracy. In this research traditional linear regression models and nonlinear neural network models have been developed for predicting hoisting times of a tower crane. It is found that nonlinear neural network models can achieve higher accuracy. However, planners may find that the regression models, which describe the relationship between the variables in more simplistic terms, could allow them to shorten the hoisting times by manipulating the input variables. The results and the merits of the models are discussed.     

Optimizing Material Procurement and Storage on Construction Sites

Efficient planning of materials procurement and storage on construction sites can lead to significant improvements in construction productivity and project profitability. Existing research studies focus on material procurement and storage layout as two separate planning tasks without considering their critical and mutual interdependencies. This paper presents the development of a new optimization model for construction logistics planning that is capable of simultaneously integrating and optimizing the critical planning decisions of material procurement and material storage on construction sites. The model utilizes genetic algorithms to minimize construction logistics costs that cover material ordering, financing, stock-out, and layout costs. The model incorporates newly developed algorithms to estimate the impact of potential material shortages on-site because of late delivery on project delays and stock-out costs. An application example is analyzed to demonstrate the capabilities of the construction logistics planning model in simultaneously optimizing material procurement decisions and storage layout plans.     

Integrated Schedule and Cost Model for Repetitive Construction Process

Several efforts have been made by many researchers to develop a model for schedule and cost integration in construction projects, but it is difficult to integrate and manage schedule and cost in an actual construction site using such a model. The integrated schedule and cost model developed in this study (1) enables the planning and control of repetitive construction processes and (2) can be used by a project manager in an actual construction site. Furthermore, an integrated schedule and cost model for the core wall construction, which is an important repetitive process in the recently booming high-rise building construction in terms of scheduling, was developed using the integration model developed in this study. It is expected that the integrated schedule and cost model developed can allow project managers to integrate the schedule and cost of repetitive construction processes more effectively and support the project managers’ decision-making.     

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.     

New Mathematical Optimization Model for Construction Site Layout

Layout of temporary construction facilities (objects) is an important activity during the planning process of construction projects. The construction area layout is a complex problem whose solution requires the use of analytical models. Existing popular models employ genetic algorithms that have proven to be useful tools in generating near optimal site layouts. This paper presents an alternative approach based on mathematical optimization that offers several important features and generates a global optimal solution. The construction area consists of an unavailable area that includes existing facilities (sites) and available area in which the objects can be located. The available area is divided into regions that are formulated using binary variables. The locations of the objects are determined by optimizing an objective function subject to a variety of physical and functional constraints. The objective function minimizes the total weighted distance between the objects and the sites as well as among the objects (if desired). The distance can be expressed as Euclidean or Manhattan distance. Constraints that ensure objects do not overlap are developed. The new approach, which considers a continuous space in locating the objects simultaneously, offers such capabilities as accommodating object adjacency constraints, facility proximity constraints, object–region constraints, flexible orientation of objects, visibility constraints, and nonrectangular objects, regions, and construction areas. Application of the model is illustrated using two examples involving single and multiple objects. The proposed model is efficient and easy to apply, and as such should be of interest to construction engineers and practitioners.     

Windmill Erection and Maintenance: Challenges for Crane Design

The wide range of crane types and sizes offered by the market expresses the responsiveness of the lifting industry to meet the variety of challenges posed by the built environment. One such emerging set of challenges is the outcome of the growing rate of wind turbine installation. Wind energy is one of the largest alternative energy production methods today, and as the global push for greener energy sources is increasing, so is the number of windmills. This paper addresses the unique lifting challenges posed by windmill installation and maintenance. These challenges have been met by leading crane manufacturers in various ways to produce products not seen before on the construction scene. The paper focuses on two such products representing two different concepts and provides the development and design rational of each. Engineering is impacted by unique height, lifting capacity, site preparation, and environmental requirements. The accelerated rate of global wind energy use, the increasing number, height, and component weight of turbine towers, and the persistent search for new territories for wind farms are likely to further produce more innovative solutions.     

Understanding and Improving Your Risk Management Capability: Assessment Model for Construction Organizations

Implementing risk management in construction projects and organizations may bring a number of benefits and therefore it is necessary to have risk management as an integral part of a construction organization’s management practice. The aim of this paper is to develop a risk management maturity assessment model for construction organizations. The paper describes the development process of a Web-based RM3 (risk management maturity model), including its contents, its validation and testing, as well as its applications. The RM3 developed has five attributes namely, management, risk culture, ability to identify risk, ability to analyze risk, and application of standardized risk management process/system. These attributes are measured against four levels: initial, repeated, managed, and optimized. It is found that the proposed RM3 was suitable and useful. Using the RM3, it is found that the Australian construction industry’s overall risk management maturity level was relatively low (where 32% rated at Level 2 and 52% rated at Level 3). Furthermore, it is found that the weakest attribute was “analyzing risks” followed by “application of standardized risk management process.” It is therefore necessary to provide more training on qualitative and quantitative risk analysis to construction personnel and to develop and apply standardized enterprise risk management. It is concluded that the proposed RM3 is suitable for construction organizations to assess their risk management maturity levels and find ways for improvement.     

Research Needs in Construction Worker Performance

No validated model of worker motivation and performance exists for the construction industry. Reasons for this are examined. Such a model has been developed outside of construction. The model is presented and discussed. Research that is needed to develop and validate the model for use in the construction industry is discussed. The need for this research to be interdisciplinary in nature, to encompass construction researchers and industrial∕organizational psychologists or organizational behaviorists, is analyzed.     

Tracking the Location of Materials on Construction Job Sites

Automated tracking of materials on construction projects has the potential to both improve project performance and enable effortless derivation of project performance indicators. This paper presents an approach by which materials tagged with radio frequency identification (RFID) tags can be automatically identified and tracked on construction sites, without adding to regular site operations. Essentially, this approach leverages automatic reading of tagged materials by field supervisors or materials handling equipment that are equipped with a RFID reader and a global positioning system receiver. To assess the technical feasibility of this approach, a mathematical model has been formulated such that the job site is represented as a grid and the location of materials within the grid is determined by combining proximity reads from a discrete range. Field experiments were conducted using an off-the-shelf RFID technology, and several metrics were developed to quantify the field performance and compare it with the theoretical positional accuracy derived from the discrete formulation.