Construction Scheduling and Progress Control Using Geographical Information Systems

Traditional scheduling and progress control techniques such as bar charts and the critical path method (CPM) fail to provide information pertaining to the spatial aspects of a construction project. A system called PMS-GIS (Progress Monitoring System with Geographical Information Systems) was developed to represent construction progress not only in terms of a CPM schedule but also in terms of a graphical representation of the construction that is synchronized with the work schedule. In PMS-GIS, the architectural design is executed using a computer-aided drafting (CAD) program (AutoCAD), the work schedule is generated using a project management software (P3), the design and schedule information (including percent complete information) are plugged into a GIS package (ArcViewGIS), and for every update, the system produces a CPM-generated bar chart alongside a 3D rendering of the project marked for progress. The GIS-based system developed in this study helps to effectively communicate the schedule∕progress information to the parties involved in the project, because they will be able to see in detail the spatial aspects of the project alongside the schedule.     

Empirical Study on the Merit of Web-Based 4D Visualization in Collaborative Construction Planning and Scheduling

This paper reports an empirical study that tested the usefulness of Web-based four-dimensional (4D) construction visualization in collaborative construction planning and scheduling. Several recent construction projects have employed 4D visualization to better understand the construction schedule and make proactive decisions to prevent logical errors in the construction sequence. Other groups have shown that construction information management with asynchronous Web-based communication can improve decision making among dispersed industry practitioners. It seems reasonable to anticipate that combining 4D visualization with Web-based information management would facilitate dispersed industry practitioners to make collaborative decisions for construction planning and scheduling. The empirical study presented here reports how experiment participants at separate locations collaboratively detected logical errors in a construction schedule when the 4D visualization model of the schedule was represented on the Web browser. Our results show that teams using 4D models detected logical errors more frequently, faster, with fewer mistakes, and with less team communication, than teams using 2D drawings and bar charts. These findings show industry practitioners empirical evidence that Web-based 4D construction visualization can improve team collaboration on construction planning and scheduling.     

Linear Scheduling and 4D Visualization

Described in this paper is a novel approach to four-dimensional (4D) computer-aided design (CAD). It involves a two-way symbiotic relationship between three-dimensional (3D) CAD software and a software implementation of linear planning that includes the ability to define a project product model and associate it with the process model. Strengths of the approach include the ability to readily modify construction sequences and examine their consequences using 4D CAD, and the ability to treat very large scale projects marked by significant repetition of their components. By building on a shared image of the project product model from both a design and construction perspective, the CAD model can be structured in a way that facilitates communication with the scheduling software and vice versa. Various challenges involved in making the 2-way process work are described, including consistency of product representation in the CAD and scheduling models, and the need to group CAD components at different levels of detail and locations to reflect the kinds of aggregation found in schedule representations of a project. The benefits of the approach include the ease with which different scheduling strategies can be explored and visualized, the links between 3D objects and activities can be maintained, and the completeness of the product model representations can be validated. A case study is used to illustrate the approach adopted and the challenges involved.     

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.     

Applicability of 4D CAD in Civil Engineering Construction: Case Study of a Cable-Stayed Bridge Project

Four-dimensional (4D) computer-aided design (CAD) has been credited with improving construction planning procedures. The integration of three-dimensional CAD with schedule information has enabled the effective detection of design and planning flaws in many construction projects. However, the benefit of 4D CAD has been centered on architectural constructions, as other areas such as civil infrastructure have seldom been the target of 4D CAD application. This paper presents a case study in which a cable-stayed bridge construction was analyzed and modeled using the 4D graphic simulation approach. The cable-stayed bridge was chosen for the case study because it suitably represents the complex nature of modern civil infrastructure. 4D CAD models were developed at three different levels of detail: activity, discrete operation, and continuous operation. The clear definitions of the three levels of detail of 4D CAD and their application results for the cable-stayed bridge are presented herein.     

Areas of Application for 3D and 4D Models on Construction Projects

In recent years more and more construction projects used three-dimensional/four-dimensional (3D/4D) models to support management tasks. However, project managers still struggle with evaluating how the 3D/4D model technology can be most efficiently applied on their specific project. One main reason for this struggle is that an account about how 3D/4D models have been used in the past is missing. This paper offers practitioners and researchers such an account of the application areas of 3D/4D model technologies including the purposes for which these technologies have been applied. The paper qualitatively aggregates the results of 26 case studies of 3D/4D model applications on construction projects to show researchers and practitioners how 3D/4D models have been applied to address project challenges. Using a “project challenge—3D/4D model application” matrix the paper explains each application area and describes why the application has been beneficial to the case study projects. The paper then analyzes the challenges that practitioners have faced with 3D/4D models on the test case projects. The main findings of this analysis are that practitioners on most of the test case projects have used the models for only one application area. The paper suggests that further research on the integration of 3D/4D model technologies into work and business processes of project teams is needed to address this opportunity for a more widespread use of 3D/4D models throughout the lifecycle of a project.     

Simulation-Based Schedule Estimation Model for ACS-Based Core Wall Construction of High-Rise Building

Many existing studies about construction schedule management focus on the planning phase of a project, particularly on schedule estimation based on the labor resources involved in the project. However, equipment resources, which are another crucial factor in the productivity of a construction project, have not been considered in existing research. Therefore, this study aimed to develop a schedule estimation model considering both labor and equipment resources. For the purpose of this study, core wall construction was selected because it is a very important construction activity in terms of schedule estimation for high-rise building construction. To develop a schedule estimation model for core wall construction, an in-depth case study was conducted. On the basis of the results of the case study, a simulation model was developed using the CYCLONE method. Finally, by using the results of the simulation, a schedule estimation model for core wall construction was developed by conducting multiple-regression analysis. By using the developed model, a project manager can easily, quickly, and accurately perform schedule estimation when there are problems that may cause construction schedule delays during the construction phase.     

Improvement Algorithm for Limited Space Scheduling

Selecting construction methods, scheduling activities, and planning the use of site space are key to constructing a project efficiently. Site layout and activity scheduling have been tackled as independent problems. Their interdependence is often ignored at the planning stage and may be dealt with—if at all—when construction is underway. Problems that may have had easy solutions if dealt with earlier, may then be expensive to remedy. This paper addresses the combined problem termed “space scheduling” and presents an algorithmic time-space trade-off model for adjusting activity durations and start dates to decrease the need for space over congested time periods. The model characterizes resource space requirements over time and establishes a time-space relationship for each activity in the schedule, based on alternative resource levels. An example illustrates the presented algorithm that generates a feasible space schedule.     

Reliability Buffering for Construction Projects

Buffering is a common practice in project planning. Project managers or schedulers have used a time contingency to guarantee the completion time of either an activity or a project. This traditional buffering, however, often fails to protect the project schedule performance, resulting in an unnecessary resource idle time. To deal with this problem, reliability buffering, a simulation-based buffering strategy, is presented. Reliability buffering aims to generate a robust construction plan that protects against uncertainties by reducing the potential impact of construction changes. The effectiveness of reliability buffering is examined by simulating a dynamic project model that integrates the simulation approach with the network scheduling approach. The research results indicate that reliability buffering can help achieve a shorter project duration without driving up costs by pooling, resizing, relocating, and recharacterizing contingency buffers. A case study of bridge construction projects also demonstrates how construction projects can benefit from reliability buffering in real world settings. Although further validation is needed, reliability buffering can potentially impact the planning and control of construction projects by improving the consideration of construction feedbacks and characteristics in buffering, and serving as an input to a dynamic project model.     

Integrated Simulation System for Construction Operation and Project Scheduling

Simulation modeling is important in predicting the productivity of construction operations and the performance of project schedules. It would be desirable if operation and project models are vertically integrated in practice. However, existing discrete event simulation systems do not allow integrating operation and project models. This paper introduces an integrated simulation system named “Construction Operation and Project Scheduling” (COPS). COPS analyzes the productivity of construction operations as well as the performance of a project schedule individually and jointly. It creates operation models, maintains these models in its operation model library, conducts sensitivity analysis with different resource combinations, finds the optimal resource combination that satisfies the user’s requirements relative to hourly production and hourly cost of the operation, feeds this information into a project schedule, and executes stochastic simulation-based scheduling. A case study is presented to demonstrate this integrated simulation system.     

PDM++: Planning Framework from a Construction Requirements Perspective

Construction requirements represent the key preconditions for construction. These include topological precedence, key resources, space requirements, etc. Consequently, identifying them is necessary for feasible construction planning to be achieved. Despite this, little attention has been given to the impact of construction requirements on a project schedule, possibly because of the lack of a good tool for representing these requirements. This paper distinguishes construction requirements into static and dynamic types, according to changes in the need of the requirement during its life cycle. A modeling framework, PDM++, is then proposed. The framework deals with schedule constraints arising from both static and dynamic construction requirements, provides greater semantic expression to capture schedule constraints unambiguously, and facilitates the representation of interdependent conditional relationships. The concept of meta-intervals is also devised to represent complex requirements involving several activities and schedule constraints, and it facilitates modeling at higher levels of plan abstractions. Finally, an illustrative case study is presented to show the applicability of PDM++ in representing schedule constraints and alternative scheduling from a construction requirements perspective.     

Multiobjective Linear Programming Model for Scheduling Linear Repetitive Projects

Linear repetitive construction projects require large amounts of resources which are used in a sequential manner and therefore effective resource management is very important both in terms of project cost and duration. Existing methodologies such as the critical path method and the repetitive scheduling method optimize the schedule with respect to a single factor, to achieve minimum duration or minimize resource work breaks, respectively. However real life scheduling decisions are more complicated and project managers must make decisions that address the various cost elements in a holistic way. To respond to this need, new methodologies that can be applied through the use of decision support systems should be developed. This paper introduces a multiobjective linear programming model for scheduling linear repetitive projects, which takes into consideration cost elements regarding the project’s duration, the idle time of resources, and the delivery time of the project’s units. The proposed model can be used to generate alternative schedules based on the relative magnitude and importance of the different cost elements. In this sense, it provides managers with the capability to consider alternative schedules besides those defined by minimum duration or maximizing work continuity of resources. The application of the model to a well known example in the literature demonstrates its use in providing explicatory analysis of the results.     

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.     

Selection of Project Delivery Method in Transit: Drivers and Objectives

This paper describes the results of research on alternative project delivery methods in transit projects in the United States. The research, sponsored by the Transit Cooperative Research Program, aimed to identify those factors that drive the decision in the choice of project delivery method. A rigorous case study analysis based on on-site structured interviews with the directors of several transit projects was used to identify decision drivers and the rationale behind the delivery method selection decision in transit agencies. The nine case studies conducted in this research represent a cross section of delivery methods, including design-bid-build/multiprime, construction manager-at-risk, design/build, and design/build-operate-maintain. The interviewees agreed that the use of alternative delivery methods have resulted in savings in schedule and cost for transit agencies. The research also found that achieving aggressive schedule compression is the most influential factor when selecting alternative delivery methods. Also, implementation of a formal risk analysis as part of the project development process appears to improve the project’s chances of meeting budget and schedule objectives.     

Model for Predicting the Performance of Project Managers at the Construction Phase of Mass House Building Projects

The need to match project managers’ (PMs) performance measures onto projects of both unique and similar characteristics has long since been acknowledged by researchers. The need for these measures to reflect the various phases of the project life cycle has also been contended in the recent past. Here, a competency-based multidimensional conceptual model is proposed for mass house building projects (MHBPs). The model reflects both performance behaviors and outcome in predicting the PMs’ performances at the conceptual, planning, design, tender, construction, and operational phases of the project life cycle. Adopting a positivist approach, data elicited for the construction phase is analyzed using multiple regression techniques (stepwise selection). Out of a broad range of behavioral metrics identified as the independent variables, the findings suggest the best predictors of PMs’ performances in MHBPs at the construction phase are: job knowledge in site layout techniques for repetitive construction works; dedication in helping works contractors achieve works schedule; job knowledge of appropriate technology transfer for repetitive construction works; effective time management practices on house units; ability to provide effective solution to conflicts, simultaneously maintaining good relationships; ease with which works contractors are able to approach the PM and volunteering to help works contractors solve personal problems. ANOVA, multicollineriality, Durbin–Watson, and residual analysis, confirm the goodness of fit. Validation of the model also reflected reasonably high predictive accuracy suggesting the findings could be generalized. These results indicate that the model can be a reliable tool for predicting the performance of PMs in MHBPs.     

Construction Project Network Evaluation with Correlated Schedule Risk Analysis Model

Schedules are the means of determining project duration accurately, controlling project progress, and allocating resources efficiently in managing construction projects. It is not sufficient in today’s conditions to evaluate the construction schedules that are affected widely by risks, uncertainties, unexpected situations, deviations, and surprises with well-known deterministic or probabilistic methods such as the critical path method, bar chart (Gantt chart), line of balance, or program evaluation and review technique. In this regard, this paper presents a new simulation-based model—the correlated schedule risk analysis model (CSRAM)—to evaluate construction activity networks under uncertainty when activity durations and risk factors are correlated. An example of a CSRAM application to a single-story house project is presented in the paper. The findings of this application show that CSRAM operates well and produces realistic results in capturing correlation indirectly between activity durations and risk factors regarding the extent of uncertainty inherent in the schedule.     

Simple Services, Inc.: A Project Management Case Study

This hypothetical case study provides a vehicle for illustrating typical project cash flows and the day-to-day events that can influence these flows. The case study also shows the interaction between project cash flows and a firm's overall financial condition. As the title implies, it is a simplified caricature of what actually happens in more complex and realistic setting, where a project manager has to worry about a multitude of problems, including the concerns of project scope schedule, and budget, plus the technical challenges of getting the job done. Isolating the management of the cash flow from the rest of these concerns allows an examination of what a project manager might need to contend with respect to cast and financial management of a project. Three industry experts-Robert J. Berg, Francis D. Leathers (Member ASCE), and Mark C. Zweig-provide analysis of the case study.     

Four-Dimensional Visualization of Construction Scheduling and Site Utilization

Four-dimensional (4D) models link three-dimensional geometrical models with construction schedule data. The visual link between the schedule and construction site conditions is capable of facilitating decision making during both the planning and construction stages. The emphases of these 4D developments have often been placed at the level of construction components. Practical features assisting site management are at times lacking in the following areas: (1) generation of site usage layouts; (2) estimation of quantities of construction materials; and (3) cost evaluation. In order to pinpoint these deficiencies, the objective of this work is to enable visual study of the effects of job progress on the logistics and resource schedules. This paper presents a 4D visualization model that is intended both to help construction managers plan day-to-day activities more efficiently in a broader and more practical site management context and to thereby add to our knowledge and understanding of the relevance of modern computer graphics to the responsibilities of the construction site manager. A brief site trial of the software is described at the conclusion of the paper.     

复杂岩土条件下岩土工程勘察工作要点

复杂岩土条件下进行岩土工程施工具有一定的复杂性和难度,因此,开始复杂岩土条件的施工工作前,需要先进行岩土工程勘察工作。因此,为了保证岩土工程勘察工作的总体质量,提升岩土工程的勘察技术是必须的。岩土勘察工作是工程项目中一个十分重要的部分,在岩土工程勘察过程中发现的各项问题都需要能够在勘察阶段就及时解决,使后期工作没有后顾之忧。一项合格的岩土工程勘察工作应当能够将勘察的场地的地质情况具体的表示出来,对未来的建设工程的施工效率和质量有积极的影响。