Formalism for Construction Inspection Planning: Requirements and Process Concept

Inspectors currently do not have adequate planning support to prevent inefficient or overlooked inspections and undetected defects. Underlying this problem is the lack of a planning formalism for specifying inspection goals and for developing and selecting inspection plans. This paper discusses the requirements for such a formalism. We describe sources of inspection knowledge and approaches for planning in general and for inspection planning specifically. We then describe a set of requirements for the representation and reasoning needed to support the use of available inspection knowledge to assist inspectors in the processes of creating sets of inspection plan alternatives and reducing that set to a smaller set of inspection plans for a given project.     

Using Gaussian and Hyperbolic Distributions for Quality Improvement in Construction: Case Study Approach

The Gaussian distribution and the 6σ principle have been widely used in the field of construction quality management with great success. This paper proposes a theoretical study on a new hyperbolic distribution using the 6σ principle to improve quality in construction management. The hyperbolic and Gaussian distributions are then numerically compared by estimating their important statistical properties, such as population in range, number of defects, yield percentage, and defects per million opportunities. The impacts of these factors are briefly discussed to give guidance to organizations in the construction industry on how to lower cost and improve project quality by prevention. A case study showing the cost data of a construction consultant company is presented. The data’s population in range and defects per million opportunities are estimated using Gaussian and hyperbolic distributions. In this particular case study, the hyperbolic distribution is shown to be more effective in quality improvement by prevention than the Gaussian distribution. This also validates the hyperbolic distribution as a suitable distribution for construction quality management.     

Ubiquitous Sensor Network for Construction Material Monitoring

Timely acquisition of construction resource information is an essential task for construction engineers and managers. Due to the harsh and dynamic construction environment, it is not easy to acquire construction information in real time. This paper presents a radio frequency identification (RFID) and ZigBee (IEEE 802.15.4)-based system to manage materials on a busy construction site where a data communications system is not in place. RFID tags are attached to and used to identify various kinds of construction materials, and the ZigBee communication technology is used to wirelessly transfer this information. To confirm the viability of our system, the RFID and ZigBee technologies were assessed using an indoor experiment. Following this, a field experiment was then conducted. On a building construction site, a range of construction materials was identified using RFID tags and this information was transferred to an end user with the help of ZigBee multihop networking. The results of the field experiment showed an acceptable reading range and rate for the proposed system. Therefore, the integrated system with RFID and ZigBee modules demonstrated great potential for improving the existing management processes for construction resources on large and complex construction sites.     

Six Sigma-Based Approach to Improve Performance in Construction Operations

Many researchers and project managers have attempted to improve project performance by applying new philosophies such as lean principle, just-in-time, pull scheduling, and last planner. However, very little research has been conducted on setting definite quantitative goals for performance improvement while considering the defect rate involved in the construction operations. This research explores practical solutions for construction performance improvement by applying the six sigma principle. This principle provides the metrics required to establish performance improvement goals and a methodology for measuring and evaluating improvement. The proposed approach is expected to achieve more reliable workflows by reducing process variability to fit in a desirable range—thereby improving the overall performance through the evaluation of the quality level in current construction operations. To verify the suggested methodology, two case studies have been presented and process simulation analyses are performed to observe the performance changes based on the six sigma principle. Critical total quality control, as the sigma level rises, is also discussed.     

Improved SWOT Approach for Conducting Strategic Planning in the Construction Industry

Strength, weakness, opportunity, and threat (SWOT) analysis has been in use since the 1960s as a tool to assist strategic planning in various types of enterprises including those in the construction industry. While still widely used, the approach has called for improvements to make it more helpful in strategic management. The project described in this paper aimed to study whether the process to convert a SWOT analysis into a strategic plan could be assisted with some simple rationally quantitative model, as an augmented SWOT analysis. By using the mathematical approaches including the quantifying techniques, the “maximum subarray” method, and fuzzy mathematics, one or more heuristic rules (HRs) are derived from a SWOT analysis. These HRs bring into focus the most influential factors concerning a strategic planning situation, and thus inform strategic analysts where particular consideration should be given. A case study conducted in collaboration with a Chinese international construction company showed that the new SWOT approach is more helpful to strategic planners. The paper provides an augmented SWOT analysis approach for strategists to conduct strategic planning in the construction industry. It also contributes fresh insights into strategic planning by introducing rationally analytic processes to improve the SWOT analysis.     

Characterization of Laser Scanners and Algorithms for Detecting Flatness Defects on Concrete Surfaces

In many construction and infrastructure management projects, it is important to ensure the flatness of concrete surfaces. Inspectors assess the quality of flat surface construction by checking whether a surface deviates from perfectly flat by more than a specified tolerance. Current flatness assessment methods, such as using a straightedge or shape profiler, are limited in the speed or density of their measurements. Laser scanners are general-purpose instruments for densely and accurately measuring three-dimensional shapes. In this paper, we show how laser scanners can be effectively used to assess surface flatness. Specifically, we formalize, implement, and validate three algorithms for processing laser-scanned data to detect surface flatness deviations. Since different scanners and algorithms can perform differently, we define an evaluation framework for objectively evaluating the performance of different algorithms and scanners. Using this framework, we analyze and compare the performance of the three algorithms using data from three laser scanners. The results show that it is possible to detect surface flatness defects as small as 3 cm across and 1 mm thick from a distance of 20 m.     

Embedded System for Construction Asset Tracking Combining Radio and Ultrasound Signals

Today’s sensor technology provides the increased opportunities for automation and improvement in data acquisition and construction processes. However, many current field practices at construction sites still rely on manual processes for asset tracking and information handling. Previous technologies, such as radio frequency identification and global positioning systems, do not provide a solution to automated asset tracking because of their limitations in terms of applicability and performance in a typical construction environment. This paper introduces a new development of an embedded sensor system for construction asset tracking by combining radio and ultrasound signals. We present the detailed hardware and software architecture and have implemented outdoor experiments to examine the accuracy and performance of the designed system. The results obtained showed the accurate distance and position estimation with enhanced networking flexibility. The findings and lessons learned from this research demonstrate the potential for future practical deployment of similar systems in many civil engineering applications.     

Construction Planning Method Using Case-Based Reasoning (CONPLA-CBR)

During the construction process, there occur many unexpected events that hinder timely completion of a project. One plausible solution in formulating a robust plan against such uncertainties is to provide the proper construction duration by utilizing as-built schedules in which past events are stored for similar future projects. Many schedulers thus develop schedules based on similar past schedules, taking into consideration the dynamic construction environment. As a result, construction schedulers normally refer to similar past schedules for their current projects. Few studies on the reuse of past schedules using case-based reasoning (CBR) have been conducted, and those that are available are limited to specific areas of construction such as apartment-building construction and boiler manufacturing. This research has an emphasis on developing a CBR-based general planning tool with higher applicability, which consists of generic attributes with the capability to be customized to the given project. To address this issue, construction planning by CBR (CONPLA-CBR) is presented as a generic planning tool for various types of construction projects. CONPLA-CBR, with the dynamic case approach and construction schedule data mart, also developed in this research, helps schedulers to utilize past schedules. CONPLA-CBR was not only verified to be of practical utility by experts, but also, because it uses past cases to which the successor relationships pertain, it does not require users to input all relationships. Whereas the proposed CONPLA-CBR generates master schedules at the preconstruction stage, its concept can also be applied to the construction stages to generate more detailed, for example, weekly or monthly, schedules. Thereby, CONPLA-CBR would enhance construction performance through the increased application of CBR in construction.     

Automated Path Planning of Cooperative Crane Lifts Using Heuristic Search

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

Total Quality Management for Construction

Traditional approaches to quality control in the construction industry are inadequate and should be replaced with the Total Quality Control concept implemented through the Quality Control (Q.C.) Circle as developed in Japan and currently in wide use throughout the manufacturing industry. The term “total quality control” is defined, and four total quality control principles are set forth on the basis of this definition. The evolution of quality control is traced from the nineteenth century to today to explain the decline in quality standards and to illustrate the need for a new approach. Unique characteristics of the construction industry are described as they relate to the Q.C. circle concept. Implementation of this concept will result in higher quality, lower costs, and increased productivity in the construction industry.     

Developing a Resource Supply Chain Planning System for Construction Projects

The high variability of construction environments results in high construction-cost variation, especially in material costs. Inadequate planning may cause material shortages that delay the project schedule or, alternatively, a substantial increase in inventory costs by producing or supplying materials earlier than they are needed at the construction site. In order to solve these problems, this paper studies steel rebar production and supply operations and establishes an optimal model that minimizes the integrated inventory cost of the supply chain. Based on the optimal model, this paper develops a decision-support system to generate a production and supply plan for a supplier and buyers of steel rebar. After utilizing the decision-support system to create the supply and production plan, this paper analyzes the results to study the influence of transaction constraints on inventory cost. This paper also discusses cases of global optimization of the inventory cost for the entire supply chain and compares them with cases of local optimization for individual members.     

Local Information Access for Search and Rescue Using Wireless Data Storage Mediums

After a natural disaster strikes buildings, it is vital to immediately retrieve the related local information for efficient search and rescue (S&R) operations. Although it seems convenient to store the required local information (e.g., information about neighborhood, buildings) in a centralized database, S&R teams usually cannot access centralized databases because the information infrastructure is usually damaged or overloaded immediately after a disaster. This paper describes the search and rescue data access point (SR-DAP) system that was designed for storing and retrieving the required local information in/from data storage units that are deployed at buildings. In the paper, the developed approach is presented, and two key technologies (i.e., radio-frequency identification (RFID) tags and wireless sensor nodes) that are used as local storage mediums in SR-DAP are empirically evaluated. The results of the field experiments show that current technologies can be effectively utilized in the developed system. However, comparison of the technologies highlights the fact that the current wireless sensor technology is advantageous over RFID technology.     

Construction Management of a Small-Scale Accelerated Pavement Testing Facility

Research in accelerated pavement testing (APT) facilities has traditionally focused on the pavement performance such as rutting and fatigue cracking, but documentation on construction management and information of the actual pavement construction quality is limited. There are typically four critical factors that need to be considered to achieve the best possible outcome in construction: cost, schedule, construction process, and quality control, and management. With the objective of developing guidelines for planning and executing construction of a small-scale APT facility, this paper presents a case study documenting and evaluating the construction process and construction management efforts of two sensor-instrumented hot mix asphalt pavement test sections built in a small-scale APT facility. The focus of the experiment was to study bottom-up fatigue cracking of the flexible pavement structure. The presented information and lessons learned serve as a template and guide for agencies pursuing this type of research and pavement construction.     

QUALICON: Computer-Based System for Construction Quality Management

This paper describes a computer-based system for construction quality management. The system tasks are derived from the elements of ISO 9001 standard and designed to integrate with other computer-aided project management functions. They can assist management in (1) the definition of requirements/criteria for design, construction, and quality management; (2) the development of inspection and test plans; (3) the tracking of actual inspection/test results; (4) the verification of their conformance to defined criteria; (5) the documentation of past experience in the form of standard templates for assisting the tasks involved; and (6) the generation of reports. A model was defined for representing the information used in the system tasks. The central role of the inspection and test plan representation was exploited to associate to construction components and processes, relevant inspections/tests, requirements/criteria, actual results, and nonconformance analyses. Templates were devised to enable the reuse of predefined packages of information, which recur from project to project. The developed system will render the assisted quality management tasks more effective. Its use was tested on data from different construction domains.     

Detection of Ungrouted Cells in Concrete Masonry Constructions Using a Dielectric Variation Approach

In this study, a new technique for detecting ungrouted cells in concrete block masonry constructions was developed. The concept, based on detecting the local dielectric permittivity variations, was employed to design coplanar capacitance sensors with high sensitivities to detect such construction defects. An analytical model and finite element simulations were used to assess the influence of the sensor geometrical parameters on the sensor signals and to optimize the sensor design. To experimentally verify the model, the dielectric properties of various materials involved in concrete masonry walls were measured. In addition, a masonry wall containing predetermined grouted and ungrouted cells was constructed and inspected using the developed sensors in a laboratory setting. Moreover, different capacitance sensors were designed and compared with respect to their sensitivity, signal-to-noise ratio, and coefficient of variation of the inspected measurements. Excellent agreements were found between the experimental capacitance signal response parameters and those predicted by the analytical and finite element models. The proposed sensor design, coupled with a commercially available portable capacitance meter, would facilitate employing this technique in the field for rapid inspection of masonry structures without the need for sophisticated data analyses usually required by other more expensive and time consuming methods.     

Integrating Construction Operation and Context in Large-Scale Construction Using Hybrid Computer Simulation

This research proposes a hybrid simulation approach based upon the principles of system dynamics (SD) and discrete event simulation (DES), which facilitates a better understanding of complex interactions among various processes in large-scale construction. The significance of the construction context that interacts with construction operations is highlighted, and a hybrid SD-DES approach is proposed as a means to capture the feedback between the two. In particular, this paper focuses on how to seamlessly integrate SD and DES within the framework of a modeling perspective. For the purpose of substantiating the discussion, a pipeline installation process is modeled using the proposed hybrid approach, with specific consideration given to how the approach can serve to address complex interactions between operation and context.     

Construction Materials Engineer, a Perspective

Construction materials engineering is a long-time discipline of civil engineering which has gained definition and recognition in recent decades due to increased demands placed on the construction materials engineer. This discipline of civil engineering involves the evaluation of construction materials, processes and products. It is a professional practice most often included as part of the project quality assurance. The role of the construction materials engineer in the design phase, the bidding phase, the construction phase and the post-construction phase of projects is examined.     

Contractor Process Improvement for Enhancing Construction Productivity

This paper presents a regression model that relates job site productivity to process improvement initiatives (PIIs) executed both before and during construction. Applied during early project stages, this model helps industry practitioners to predict the expected value of labor productivity based on certain inputs related to preconstruction planning and construction execution. The model demonstrates the strong relationship of project performance to a variety of PIIs including design completeness, definition of a project vision statement, testing oversight, and project manager experience and dedication. The correlational research methodology targeted 75 projects representing approximately $274.53 million in civil construction. The data collection effort considered 45 PIIs (independent variables) using quantitative and qualitative measures. The modeling technique involved the use of multiple linear regression, a method that exploits available data from multiple, independent sources to focus on specific outcomes. The model was developed directly from contractor specific information and subjected to rigorous statistical analysis. The model provides project managers as front line industry practitioners with a deliberate yet practical approach to project management and productivity enhancement. The modeling results include verification analysis and a discussion of the model’s usefulness and limitations.     

Effects of Schedule Pressure on Construction Performance

Accelerating a project can be rewarding. The consequences, however, can be troublesome if productivity and quality are sacrificed for the sake of remaining ahead of schedule, such that the actual schedule benefits are often barely worth the effort. The tradeoffs and paths of schedule pressure—and its causes and effects—are often overlooked when schedule decisions are being made. This paper analyzes the effects that schedule pressure has on construction performance, and focuses on tradeoffs in scheduling. A research framework has been developed using a causal diagram to illustrate the cause-and-effect analysis of schedule pressure. An empirical investigation has been performed by using survey data collected from 102 construction practitioners working in 38 construction sites in Singapore. The results of this survey data analysis indicate that advantages of increasing the pace of work—by working under schedule pressure—can be offset by losses in productivity and quality. The negative effects of schedule pressure arise mainly by working out of sequence, generating work defects, cutting corners, and losing the motivation to work. The adverse effects of schedule pressure can be minimized by scheduling construction activities realistically and planning them proactively, motivating workers, and by establishing an effective project coordination and communication mechanism.     

应用检测仪诊断炼焦消火泵故障

介绍应用ＨＹ－１０２型测试仪对水泵电机振动情况进行故障判断的方法。通过诊断分析，预知设备的运行情况，适时安排检修，避免故障状态下继续运行造成损失。