Project owners' role in improving constructability of construction projects: an example analysis for Indonesia

Constructability is an approach that links the design and construction processes, which can lead to significant savings in both cost and time required for completing construction projects. Improving constructability of construction projects is the responsibility of all project stakeholders: owners, designers and contractors. As the owners have the most authority in enforcing the implementation of constructability, the owners' awareness of the benefit of improved constructability is the most important. Project owners must be aware that the decisions that are made in the initial stages of planning and design are difficult and costly to change once construction begins. A questionnaire survey was used to gain information on the Indonesian construction project owners' understanding of constructability by assessing the current constructability practices and their impact on project performance. The study shows that project owners in Indonesia do have some understanding of the importance of constructability. However, the traditional approach to project delivery, which is the preferred method by most of them, limits their option for involving construction personnel in the pre‐construction phases.     

A review of current practice in constructability improvement: case studies on construction projects in Indonesia

The concept of constructability emerged in the late 1970s, evolved from studies into how improvement can be achieved to increase cost efficiency and quality in the construction industry. It is an approach that links the design and construction processes. The studies in the USA, UK and, later, in Australia have demonstrated that improved constructability has lead to significant savings in both cost and time required for completing construction projects. However, in implementing constructability improvement, it is important to consider the uniqueness of the construction industry in a specific country. To improve constructability in Indonesian construction projects, two main questions need to be answered: how is construction integrated into planning and design in existing practice and how can constructability be improved. Case studies indicate that the contractual relationships between the project team members determine the options for early involvement of construction personnel, and that the current constructability practices have had some positive impacts on project performance. In addition to a reduction in constructability problems, current constructability practices have enabled significant economic savings.     

Moving beyond the fourth dimension with an IFC-based single project database

4D CAD has been an active research area for many years. The first generation 4D tools simulated construction schedules and demonstrated the potential benefits in several case studies. Researchers tried to improve the functionality of the first generation 4D tools by adding annotations and highlighting the building elements that have problems. The future generation 4D tools are expected to include more than these. It has been envisioned that 4D models would be part of project databases in order to take decisions related with different project dimensions.This paper presents the development and implementation of a new 4D planning tool which is a part of a product model-based project database. This tool brings the 4D simulation and cost estimation together and aims to contribute to what-if analysis in construction projects. The last part of the paper presents a case study in which the proposed prototype is evaluated.     

Key determinants for construction schedule performance

This study identifies key determinants for construction schedule performance from a list of factors related to the project manager, project team, planning and control efforts. Objective data on completed projects was analysed using neural network approach. Five key determinants identified are: (1) time devoted by the project manager to a specific project; (2) frequency of meetings between the project manager and other project personnel; (3) monetary incentives provided to the designer; (4) implementation of constructability program; and (5) project manager experience on projects with a similar scope. The importance of these key determinants is discussed as it relates to achieving specific construction schedule performance.     

Applicability of 4D modeling for resource allocation in mega liquefied natural gas plant construction

Four-dimensional (4D) modeling has gained much potential in improving construction process design and planning. The integration of three-dimensional model with scheduling information has been shown to enable the effective detection of construction process design and planning flaws. However, the research work in 4D has been predominantly focused on the building construction industry. 4D has been rarely explored in the oil and gas industry, particularly Liquefied Natural Gas (LNG) plant construction. It is very difficult to conceive the scale and complexity of mega-projects in the LNG sector. This paper presents a study with the goal of investigating the feasibility and benefits of 4D in supporting LNG construction projects. 4D models were developed at both the activity level and the operations level, and geometry-based virtual construction was implemented to rehearse the construction process for the purpose of identifying potential risks and safety issues. These models were used for synergistic planning for the whole project and for resource scheduling. It has been demonstrated in this paper, mega LNG construction projects can benefit from 4D in terms of improved process planning and control.     

Optimizing construction planning schedules by virtual prototyping enabled resource analysis

The inherent uncertainty and complexity of construction work make construction planning a particularly difficult task for project managers due to the need to anticipate and visualize likely future events. Conventional computer-assisted technology can help but is often limited to the constructability issues involved. Virtual prototyping, however, offers an improved method through the visualization of construction activities by computer simulation — enabling a range of ‘what-if’ questions to be asked and their implications on the total project to be investigated.This paper describes the use of virtual prototyping to optimize construction planning schedules by analyzing resource allocation and planning with integrated construction models, resource models, construction planning schedules and site-layout plans. A real-life case study is presented that demonstrates the use of a virtual prototyping enabled resource analysis to reallocate space, logistic on access road and arrange tower cranes to achieve a 6-day floor construction cycle.     

Quantitative analysis of workflow, temporary structure usage, and productivity using 4D models

This paper presents time–space analyses of construction operations supported by quantitative information extracted from 4D CAD models. The application of 4D models is a promising approach to help introduce construction innovations and to evaluate construction alternatives. Current analyses of 4D models are mainly visual and provide project stakeholders with a clear, but limited, insight of construction planning information. This practice does not take advantage of the quantitative data contained in 4D models. We use two 4D models of an industry test case to illustrate how to analyze, compare, and present 4D content quantitatively (i.e., workspace areas, work locations, and distances between concurrent activities). This paper shows how different types of 4D content can be extracted from 4D models to support 4D-content-based analyses and novel presentation of construction planning information. We suggest further research aimed at formalizing the contents in 4D models to enable comparative quantitative analyses of construction planning alternatives. Formalized 4D content can enable the development of reasoning mechanisms that automate 4D-model-based analyses and provide the data content for presentations of construction planning information.     

4D CAD技术在施工管理中的应用研究

4D CAD技术属于计算机技术在工程施工领域应用的一项新技术，本文作者通过论述4D CAD技术的发展，分析了4D CAD技术在施工管理中的优势。通过对比分析常见4D CAD软件的基本功能，结合一座大型桥梁工程的施工实践，具体说明4D CAD技术的优点和应用障碍。最后，提出4DCAD技术发展的趋势和方向。     

Decision support for tower crane selection with building information models and genetic algorithms

Tower cranes are major construction equipment that is highly demanded in construction projects. The planning process for tower cranes utilization starts in early stages of the construction projects. Poor selection could incur extra costs on the construction projects or cause delays in project duration. The planning procedures for tower cranes include selection, allocation and operation. This paper presents a framework for the selection of tower cranes types and locations at construction sites. The framework considers three main models: 1) decision making model to select the tower crane type, 2) optimization model for the selection of the ideal number and location of tower cranes, and 3) 4D simulation model to simulate tower crane operations. Several clash detection scenarios are presented to assure the safety operation of the tower crane group. A case study is shown herein to demonstrate the capabilities of the developed framework.     

Application of 4D for dynamic site layout and management of construction projects

Construction schedules and site space arrangement are essential to project management, as they directly influence security, machine running, material deployment, power distribution as well as construction progress and cost. There has been a strong need for more effective planning and management of site space and facilities. This paper introduces a 4D Integrated Site Planning System (4D-ISPS) which integrates schedules, 3D models, resources and site spaces together with 4D CAD technology to provide 4D graphical visualization capability for construction site planning. The features of 4D-ISPS are described in detail. The implementation techniques of this system are also discussed and a real life case is presented.     

Virtual construction of architecture using 3D CAD and simulation

3D modeling and computer simulations provide new ways for architecture students to study the relationship between the design and construction of buildings. Digital media help to integrate and expand the content of courses in drafting, construction and design. This paper describes computer-based exercises that intensify the student's experience of construction in several courses from sophomore to senior level. The courses integrate content from drafting and design communication, construction, CAD, and design.Several techniques are used to strengthen students' awareness and ability in construction. These include:

• •Virtual design–build projects in which students construct 3D CAD models that include all elements that are used in construction.
• •Virtual office in which several students must collaborate under the supervision of a student acting as project architect to create a 3D CAD model and design development documents.
• •Virtual sub-contracting in which each student builds a trade specific 3D CAD model of a building and all of the trade specific models must be combined into a single model.
• •Construction simulations (4D CAD) in which students build 3D CAD models showing all components and then animate them to illustrate the assembly process.
• •Cost estimating using spreadsheets.

These techniques are applied and reapplied at several points in the curriculum in both technical laboratory courses and design studios.This paper compares virtual construction methods to physical design–build projects and provides our pedagogical arguments for the use of digital media for understanding construction.     

A study of preproject planning and project success using ANNs and regression models

It has long been recognized by the industry practitioners that how well preproject planning is conducted has a great impact on project outcome. Through industry project data collection and model analysis, this research intends to investigate the relationship between preproject planning and project success. Preproject planning and project performance information from 62 industrial projects and 78 building projects, representing approximately $5 billion U.S.D. in total construction cost, is collected and used for this research analysis. Based on the information obtained, preproject planning is identified as having direct impact on the project success (cost and schedule performance). Two techniques were then used to develop models for predicting cost and schedule performance: statistical regression analysis, and artificial neural networks (ANNs). The research results provide a valuable source of information that supports better planning in the early stage of the project life cycle and have positive impact on the final project outcome.     

Generating, evaluating and visualizing construction schedules with CAD tools

Collaborative AEC technologies centering around component-based CAD models support architectural and structural perspectives. The construction perspective is often neglected because an important dimension for construction–time–is missing. Construction planners are forced to abstract CAD model building components into schedule models representing time. 4D-CAD (3D-CAD+time) removes this abstraction by linking a 3D building model and schedule model through associative relationships. Adding time to 3D-CAD models extends the use of CAD tools from the design phase to the construction phase. Although commercial 4D tools exist that allow planners to build 4D models and create graphic simulations of the construction process, these tools lack features to support analysis of these models, easy generation and manipulation of such models, and realistic visualizations of the construction process. This paper discusses these shortcomings, highlights requirements for CAD tools to support construction planning tasks, and describes our efforts to develop 4D tools that generate 4D+x models that more realistically represent the construction process.     

4D CAD Based Method for Supporting Coordination of Urban Subsurface Utility Projects

Coordinators of inner city utility construction works face increasing difficulty in managing their projects due to tight physical restrictions, strict deadlines and growing stakeholder fragmentation. This paper therefore presents a 4D CAD based coordination method that supports project plan scoping, formalizing and synchronizing. We developed and implemented the method by conducting ethnographic action research in four project cases. In these projects, we observed that 4D-models generated with the method allowed practitioners to identify project interfaces and conflicts, to identify schedule shortcomings and to evaluate delays. By introducing the method and reporting on its empirical evaluation we extend 4D CAD's domain of applicability with mid and small-sized utility projects and address a need for 4D implementation studies.     

Trends of 4D CAD applications for construction planning

Since the early 1990s, there has been a growing interest in four‐dimensional computer aided design (4D CAD) for construction project planning. Commercial 4D CAD applications are becoming more accessible and the use of this technology allows the construction planner to produce more rigorous schedules. A review of the technical competencies of these packages highlights that most of the commercially available packages concentrate on the use of 4D CAD simulations for aesthetic visualization purposes. Very few packages offer the ability to carry out analytical tasks on the developed simulation and this is often left to the interpretation of the user. A thorough appraisal of emerging research developments in 4D planning highlights that this technology is employed for various applications; however, the amount of detail required in a 4D simulation is still ambiguous. A model is proposed to determine the attributes required for use with each of the various applications of 4D CAD simulations. Finally, various lines of future research are highlighted, including the need for improved use of data exchange standards and the automation of linking the construction tasks to the 3D CAD model.     

Development of a 4D object-based system for visualizing the risk information of construction projects

Recently, risks in construction projects have been gradually increasing due to the upsizing of construction projects and the introduction of diverse new methods of construction. Risk management is employed to address potential risks, and on most construction sites risk management is implemented based on managers' intuition. Furthermore, risk analysis information is presented based on complicated numerical analysis, which reduce its usability in practical work. The purpose of this research was to develop a risk management visualization system that can analyze the degrees of risks in construction projects using objective quantifying methodologies for gathering risk information. The information is then presented based on the degree of risks involved. This system can be utilized as a tool to effectively respond to various types of construction risk information. To this end, the fuzzy and analytic hierarchy analysis (AHP) techniques are used as methods to quantify risk information. To visualize the risk information analyzed, a simulation system for visualizing risk information is developed along with a four-dimensional (4D) CAD system. The proposed system is applied to a sample construction project to verify its usability. A work space optimization method that considers risk information and work space is also suggested for further development of the system.     

4D CAD model updating using image processing-based construction progress monitoring

For a four-dimensional (4D) computer-aided design (CAD) model to be useful for users throughout a construction project, the model must be updated in a timely and accurate manner during the construction. Only when it has been properly updated can the 4D CAD model reflect the real progress of a construction site to inform managerial decision making. However, updating a 4D CAD model is time-consuming and labor-intensive because the full updating process, from site data acquisition to 4D model regeneration, is typically conducted manually. This difficulty in updating a 4D model discourages industry practitioners from actively adopting 4D models. This paper presents an image processing-based methodology for the automatic updating of a 4D CAD model. Characterized by 3D CAD-based image mask filters, color-based noise removal, and area-based progress calculation, the image processing approach provides as-built schedule information. The schedule information is then automatically integrated with an existing 3D CAD model in batch-processing modes to produce the updated 4D CAD model. The proposed methodology was applied and verified in a cable-stayed bridge construction project and is expected to facilitate the wider use of 4D CAD models in the construction industry.     

Visualizing high-rise building construction strategies using linear scheduling and 4D CAD

Project teams face ever increasing pressure to deliver projects as quickly as possible. To meet these demands, contractors are faced with the need to explore various construction strategies in order to meet delivery dates, and to assure themselves as to the achievability and quality of a schedule. Various visual representations of a project's schedule and associated information combined with visual representations of the project in progress, i.e. 4D CAD, can assist with these tasks of identifying effective construction strategies for shortening project duration, assessing their workability, and judging schedule quality. Such visual representations aid communication amongst project staff and facilitate brain-storming, and, implemented well they can provide clear, fast, and multi-dimensional feedback to the project team. In this paper, we describe aspects of our work which is directed at formulating a dynamic visualization environment that links 3D CAD, a generalization of traditional CPM which embraces linear scheduling, dual product representations (scheduling and CAD system) and their mapping onto each other, and schedule and CAD graphics in a manner which facilitates the relatively rapid exploration of alternative construction method and scheduling strategies for large scale linear projects (e.g. high-rise buildings, bridges, etc.). Requirements of such an environment include quickness, treating scale, working at multiple levels of detail, dealing with design variability, and realistic representation of the work. Use is made of a realistic example to highlight aspects of our approach and identify important issues that must be addressed if a visualization environment useful for construction professionals is to be developed.     

Dynamic quantification and analysis of the construction workspace congestion utilising 4D visualisation

This work focuses on identifying and minimising workspace congestions between construction activities' execution space. It develops a methodology and tool to assist planners with the assignment of activities' execution space, as well as identification and visualisation of workspace congestion. A literature review of workspace planning techniques revealed that traditional workspace planning techniques might not be able to detect and resolve workspace congestions.This paper establishes a new concept for ‘visualising workspace competition’ between the progressing activities through a number of objectives. A Critical Space-time Analysis (CSA) approach was developed to model and quantify workspace congestions. Subsequently a multi-criteria function embedding spatial and schedule related criteria, was designed to measure the severity of workspace congestions. A dynamic 4D simulation environment was developed by utilising three workspace planning features, these are: the twelve execution patterns, the three different work rate distributions, and a time-based simulation of the progressing quantities of work. These were encapsulated in an innovative visual 4D CAD tool dubbed PECASO (Patterns Execution and Critical Analysis of Site-space Organisation), which was developed and evaluated in a case study project.The paper concludes that the CSA approach reduces the number of competing workspaces and conflicting volumes between occupied workspace. The PECASO tool assists the planners' decision making to produce a better execution strategy for a given project schedule. It also contributes to future research and knowledge of 4D workspace planning.     

Bridge information models for construction of a concrete box-girder bridge

Large construction projects involve collaboration among a large number of participants with different specialised knowledge from various construction processes. A readily accessible bridge information model is needed to enable engineers to innovate prefabricated bridge construction. Three-dimensional (3D) information models can include multi-layered information for different users such as designer, contractor and owner. A construction project life-cycle management system was suggested to integrate and to accumulate valuable information. In this paper, 3D bridge information models for an international concrete bridge construction project were built to integrate design and construction processes. The 3D bridge models were realised by considering work breakdown structure and product breakdown structure to enable digital mock-up and design enhancement and to shorten the learning time of construction engineers. The models were also utilised for the fabrication of precast box segments and for the geometry control during construction. Assessment from the construction director was discussed and additional usage of the bridge information models was suggested.