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.     

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     

Feasibility of Automated Monitoring of Lifting Equipment in Support of Project Control

One of the differences between industrial manufacturing or processing plants and construction sites is the temporary nature of the construction site, which has traditionally precluded installation of sophisticated production monitoring systems. Monitoring of production progress, cost, and quality is performed almost exclusively manually, with the result that it is expensive and approximate, and is commonly delivered with a time lag that does not allow for an effectively closed control loop. Automated monitoring of construction lifting equipment to provide useful feedback information for project management is a strong potential candidate; almost all components and materials must be transported by machines, and monitoring of machines is relatively straightforward. A system concept, employing a “black box” monitor and an electronic building information model, was developed. A field study was conducted to test the feasibility of the concept. The results indicate that the system is technically feasible, and offers the potential to deliver real-time, accurate project control information at very low cost.     

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.     

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.     

Genetic Algorithms for Construction Site Layout in Project Planning

Construction site layout is concerned with the existence, positioning, and timing of the temporary facilities that are used to carry out a construction project. Typically these problems are very complicated to formulate and difficult to solve. They are, however, very important to virtually any construction project, since the site layout can significantly affect the cost of the project. This paper describes the general site layout problem from both a theoretical and a practical point of view. It proposes genetic algorithms as a possible solution technique and includes a theoretical example of positioning temporary facilities. This is extended to a practical problem in which the cost of movement is modeled realistically using an augmented genetic algorithm. Some preliminary conclusions are drawn for the application of genetic algorithms to construction site layout problems.     

Effective Practice Utilization Using Performance Prediction Software

A successful capital facility project requires effective usage of practices to satisfy the expected high level of project objectives. To provide an effective practice usage plan, the impacts of implementing practices need to be quantified and better methods or tools for practice usage plan and control are also required. Despite a number of efforts at quantifying the impact of practice usage, little interest has been shown in developing the tools and techniques for improved implementation of practice use. This paper develops performance prediction models for project cost and schedule performance using predictive discriminant function analysis (DFA). The models are integrated into an automated and practical software program named the DFA program that helps deliver effective and dynamic project planning. The DFA program has a user-friendly interface that project managers or field engineers can easily apply to their projects to predict cost and schedule performance and to allow for improvement where possible. An overall project performance improvement process using the DFA program application is provided.     

Resource-Activity Critical-Path Method for Construction Planning

In this paper, a practical method is developed in an attempt to address the fundamental matters and limitations of existing methods for critical-path method (CPM) based resource scheduling, which are identified by reviewing the prior research in resource-constrained CPM scheduling and repetitive scheduling. The proposed method is called the resource-activity critical-path method (RACPM), in which (1) the dimension of resource in addition to activity and time is highlighted in project scheduling to seamlessly synchronize activity planning and resource planning; (2) the start/finish times and the floats are defined as resource-activity attributes based on the resource-technology combined precedence relationships; and (3) the “resource critical” issue that has long baffled the construction industry is clarified. The RACPM is applied to an example problem taken from the literature for illustrating the algorithm and comparing it with the existing method. A sample application of the proposed RACPM for planning a footbridge construction project is also given to demonstrate that practitioners can readily interpret and utilize a RACPM schedule by relating the RACPM to the classic CPM. The RACPM provides schedulers with a convenient vehicle for seamlessly integrating the technology/process perspective with the resource use perspective in construction planning. The effect on the project duration and activity floats of varied resource availability can be studied through running RACPM on different scenarios of resources. This potentially leads to an integrated scheduling and cost estimating process that will produce realistic schedules, estimates, and control budgets for construction.     

Kinematics of Excavators (Backhoes) for Transferring Surface Material

To use construction machines effectively in the dark, severe weather, or hazardous and/or unhealthy environments, their operations should be controlled automatically. It can be realized if the kinematics and dynamics of the machine are understood. To help achieve this goal, the kinematics of specific construction machines—excavators (backhoes and loaders)—are investigated here. A systematic procedure is presented to assign Cartesian coordinate frames for the links (joints) of an excavator. Then, the homogeneous transformation matrices that relate two adjacent coordinate frames are given. The kinematic relations of the pose (position and orientation) of the bucket, the joint shaft angles, and the lengths of the cylinder rods in the hydraulic actuators for an excavator are studied. Explicit expressions for the forward and backward (inverse) kinematic relations are presented. Then, the corresponding kinematic velocity relations for the excavators are developed. The kinematic relations presented provide the foundation for engineers to realize the automatic computer‐controlled operations of the machine.     

Characterization and Search of Construction Inspection Plan Spaces Developed Using a Component-Based Planning Approach

Formal construction inspection planning is needed to help reduce the incidence of overlooked or inefficient inspections, and to help realize the potential of emerging sensing technologies. Prior publications by the authors have presented requirements for such an approach and a component-based inspection planning implementation as an approach in addressing some of the requirements towards formal construction inspection planning. Implementation of such a component-based approach for typical construction examples, however, leads to the generation of large, rugged search spaces. This paper first describes the characteristics of search spaces that are generated using a component-based approach to illustrate which search mechanisms are appropriate to explore these search spaces. The paper then describes a set of search algorithms and heuristics that were investigated and evaluated for searching construction inspection plans. Specific discussions on how these algorithms performed in searching within inspection planning spaces are provided based on experiments conducted using a testbed characterizing a construction site and a building performance monitoring decision-making example.     

Automated Generation of Work Spaces Required by Construction Activities

To provide a safe and productive environment, project managers need to plan for the work spaces required by construction activities. Work space planning involves representing various types of spaces required by construction activities in three dimensions and across time. Since a construction schedule consists of hundreds of activities requiring multiple types of spaces, it is practically impossible to expect project managers to specify manually the spatiotemporal data necessary to represent work spaces in four dimensions. This paper presents mechanisms that automatically generate project-specific work spaces from a generic work space ontology and a project-specific IFC (industry foundation class) based 4D production model. The generation of these work spaces leads to a space-loaded production model. Within this model, work spaces are represented as being related to the relevant construction activities and methods and as having attributes that describe when, where, and how long they exist, and how much volume they occupy. These space-loaded production models enable richer 4D CAD simulations, time-space conflict analysis, and proactive work space planning prior to construction.     

Effect of Preconstruction Planning Effort on Sheet Metal Project Performance

The complexity of construction industry requires the identification of work tasks and the coordination of interactions among them. As a result, construction planning is considered to be one of the most critical steps toward success and is the main focus of past research. Consequently, little research has been performed regarding the preconstruction planning, which is the planning completed by the contractor in the period between project award and project execution. This paper focuses on sheet metal preconstruction planning, primarily that of mechanical and heating ventilations and air conditioning contractors. The research was completed in three phases: phase one gathered data on the current state of preconstruction planning, phase two developed a model sheet metal preconstruction planning process to be used by sheet metal contractors, and phase three validated the model preconstruction planning process. Based on project data collected for this research, projects that used a planning process similar to the model process performed more successfully—they achieved an average profit margin of 23% while projects that were poorly planned experienced an average profit margin of ?3%.     

Use of Quality Function Deployment in Civil Engineering Capital Project Planning

Capital project development is a complex process that takes many years to implement. The development of a capital project usually undergoes several rounds of design evolution, and as a result the basic and original customer’s requirements may be easily sidetracked or may deviate from the client’s objectives. Quality function deployment (QFD) is a tool that can be used to keep track of customers’ requirements. The objective of this paper is to explore the applicability of QFD in the civil engineering capital project planning process by developing a QFD model with an application template for the process. To verify and demonstrate how the QFD model works, data are obtained from two real-life projects and fed into the template for back-analysis. The findings suggest that QFD can be successfully used in the capital project planning process as a road map to keep track of the original requirements, facilitate good communication across the hierarchy, and serve as a tool for evaluating project alternatives.     

Non-Unit-Based Planning and Scheduling of Repetitive Construction Projects

Repetitive scheduling methods are more effective than traditional critical path methods in the planning and scheduling of repetitive construction projects. Nevertheless, almost all the repetitive scheduling methods developed so far have been based on the premise that a repetitive project is comprised of many identical production units. In this research a non-unit-based algorithm for the planning and scheduling of repetitive projects is developed. Instead of repetitive production units, repetitive or similar activity groups are identified and employed for scheduling. The algorithm takes into consideration: (1) the logical relationship of activity groups in a repetitive project; (2) the usage of various resource crews in an activity group; (3) the maintaining of resource continuity; and (4) the time and cost for the routing of resource crews. A sample case study and a case study of a sewer system project are conducted to validate the algorithm, as well as to demonstrate its application. Results and findings are reported.     

Systematic Evaluation of Construction Equipment Alternatives: Case Study

Selecting the right equipment for the project is inherently a multifaceted cost and benefit evaluation process that is further compounded by the complexity of today’s building projects and the lack of systematic tools for the consideration of soft factors. This paper presents a detailed application example of a model based on an analytical hierarchy process (AHP) approach. This model was developed to address the difficulties experienced during the multifaceted process. The example illustrates how an AHP-based model helps address the multitude of qualitative, intangible factors, both among the factors themselves and then vis-à-vis costs, by means of a systematic and traceable process. The method enables project managers and their equipment selection teams to exercise their knowledge, intuition, and professional judgment, and at the same time to address the context and specifics of the particular projects under examination. The example should be helpful for construction practitioners dealing with similar equipment selection issues. Researchers may find interest in the implementation of a multiattribute-decision-making method for a typical construction management problem.     

Measuring Effectiveness of Materials Management for Industrial Projects

A measurement of the effectiveness of the material management process is needed in order to analyze problems, suggest solutions, and assess the impact of modifications to the process. Such measurement is also required for any benchmarking effort. Research was conducted to apply a set of key effectiveness measures on 17 ongoing industrial projects. This research showed that most of the measures were easily obtainable, but some were difficult to obtain. Research also showed that it was possible to obtain the highest score on all measures, indicating that best practice in industry is achieving highly successful results. Most of the projects appeared to have a highly effective materials management process, as indicated by the fact that median values of these measures were much closer to the best values than those of the mean values. A utilization plan for the measurement of the effectiveness of the material management process is presented.     

Improving Cost Estimates of Construction Projects Using Phased Cost Factors

Central to cost-based competition is the capability to accurately predict the cost of delivering a project. Most literature on cost estimation focuses on specific estimation methods as generic techniques and little attention has been paid to the unique requirements at each project stage. This note attempts to identify the critical factors for effective estimation at various stages of typical construction projects. Drawing from organization control theory and cost estimating literature, this note develops a theoretical framework that identifies the critical factors for effective cost estimation during each project phase of a conventional construction project. The underlying logic is that as a cost estimating effort progresses, both task programmability and output measurability improve. As a result, control effort will shift from input-oriented control to a combination of output and behavior control.     

Criticism of CPM for Project Planning Analysis

Published criticism in recent years concerning the inadequacy of Critical Path Method (CPM) as a project planning tool is identified and grouped under six major headings with reference to the publications in which the criticism were contained. These are answered from the writer's field experience and from experiences published by other authors. The object of the analysis is to see whether or not CPM as a project planning tool can meet the required functions of planning in construction, including consideration of legal and contractual framework and the complex and interdisciplinary nature of the project environment. The analysis reveals that, despite numerous criticism, project and construction planning should be done using CPM scheduling. Main factors affecting successful planning are realistic estimation of the productivity of crews in the context of expected job‐management efficiency conditions, and inclusion of sufficient time buffers between dissimilar trades. CPM is found to be equally useful as a planning tool for linear or repetitive projects. The limitations of this technique are identified in terms of the defined planning functions in the engineering phase of capital projects. A broad model for management of the engineering phase in revenue‐generating projects is suggested.