Process and Case Illustration of Construction Innovation

This paper describes the major stages and component steps leading to the realization of the technical and commercial potential of a new construction technology. It encompasses a process of innovation and invention, which is generically applicable to any construction innovation. A case illustration of a new asphalt compaction technology is also described within each stage to provide a “real life” example. Motivation for the new technology came from the fact that existing, conventional rollers can cause serious damage to the compacted asphalt mat at the time of construction. This damage is in the form of construction cracks, often termed “roller checking,” which can result in accelerated, in-service deterioration. The new technology originally termed the “Asphalt Multi Integrated Roller” (AMIR), overcomes the problems of current rollers through stiffness compatibility with the asphalt mix and a different geometry than conventional rollers. Commercial realization of the technology has been achieved through a new generation of AMIR, termed “HIPAC.” The paper also provides background on the issues of concern to pavement engineers, including limitations of current compaction methods. It explains in functional terms the unique difference provided by the new technology. As well, it describes the major hurdles that were overcome to achieve commercial realization.     

Evaluation of Pavement Friction Performance on Interchange Ramps at Network Level

Most state highway agencies conduct inventory friction testing on mainline highways to monitor network pavement friction performance. However, no state highway agencies have been reported to monitor pavement friction performance on interchange ramps. Interchange ramps constitute a large portion of the interstate highway facilities. Great concerns have arisen nationwide due to the increasing number of accidents in the ramp areas. This paper presents an effort to evaluate pavement friction performance on interchange ramps in Indiana. It is found that the overall average posted speed is 38?mi/h on interchange ramps, which is close to the test speed of 64?km/h recommended by AASHTO for establishing pavement friction requirements. In addition, pavement friction seemed to decrease as ramp curvature decreased. In general, three tests at the entrance, midpoint, and exit can provide information sufficient to evaluate pavement friction performance on an entire ramp. The 15th percentile friction number for overall interstate mainline pavements is 30 and 29 for the selected ramps.     

Experimental Investigation of the Influence of Moisture on the Bond Behavior of FRP to Concrete Interfaces

The effects of moisture on the initial and long-term bonding behavior of fiber reinforced polymer (FRP) sheets to concrete interfaces have been investigated by means of a two-year experimental exposure program. The research is focused on the effects of (1) moisture at the time of FRP installation, in this paper termed “construction moisture,” consisting of concrete substratum surface moisture and external air moisture; and (2) moisture, in this paper termed “service moisture,” which normally varies throughout the service life of concrete. Concrete beams with FRP bonded to their soffits were prepared. Before bonding, concrete substrates were preconditioned with different moisture contents and treated with different primers. The FRP bonded concrete beams were then cured under different humidity conditions before being subjected to combined wet/dry (WD) and thermal cycling regimes to accelerate the exposure effects. Adhesives with different elastic moduli were used to investigate the long-term durability of each adhesive when subjected to accelerated WD cycling. Pull-off tests and bending tests were conducted at the beginning of the cycling and then again after 8 months, 14 months, and 2 years of exposure so as to evaluate the tensile and shear performance of the FRP-to-concrete interfaces. It was found that the effect of the concrete substrate moisture content on short-term interfacial bond performance could be eliminated if an appropriate primer was used. All FRP-to-concrete bonded joints failed at the interface between the primer and concrete after exposure while those not exposed usually failed within the concrete substrate. After exposure to an environment of accelerated WD cycles, it was also found that the interfacial tensile bond strength degraded asymptotically with the exposure time while the flexural capacity of the FRP sheet bonded plain concrete beams even increased. The mechanism behind the above, which is an apparently contradictory phenomenon, is discussed.     

Line‐of‐Balance Scheduling in Pavement Construction

Linear Scheduling Methods are best suited to projects that display repetitive characteristics, but their use in the construction industry is limited. Line‐of‐Balance (LOB) is a Linear Scheduling Method that also makes use of network technology. Its benefits and shortcomings are investigated in a high‐way surface treatment project where LOB has been used experimentally. It was determined that LOB is extremely sensitive to errors in man hour, crew size, and activity duration estimates. There are also problems of a visual nature with the presentation of the diagram. On the other hand, LOB allows a better grasp of the project than any other scheduling technique because it is possible to adjust activities' rates of production. It provides a smooth and efficient flow of resources and requires less time and effort to produce than network schedules. Research to make Linear Scheduling Methods more attractive is recommended.     

Effect of Contamination on Reinforcing Bar-Concrete Bond

Current specifications require the removal of reinforcing bar contaminants that reduce bond prior to placing concrete. This study focused on the interactions of contaminant type, bar size, epoxy coating, concrete strength, and test method (beam and direct pullout). The majority of the beam tests showed the bond strength was not significantly affected, with certain exceptions. However, the direct pullout tests revealed a significant reduction of bond strength in most situations. Although the bond strength was still greater than that required by code, it is recommended that specifications for removal of contaminants should not be relaxed until further study is performed.     

Case Study on the Evaluation of Equipment Flow at a Construction Site

The purpose of this study is to evaluate the effects of traffic flow of construction equipment. A large construction project requires large quantities of construction equipment. This volume can result in traffic congestion in the flow of construction equipment, which also lowers the overall efficiency of construction operations. In particular, this effect can be serious in the area where traffic bottlenecks are most likely. This study applies a multiagent-based simulation modeling approach to a real project. Through a case study, this study evaluates how traffic flow of construction equipment influences the efficiency of that equipment in construction operations and, moreover, the schedule of a project.     

Determination of Nonlinear Softening Behavior at FRP Composite/Concrete Interface

For concrete beams and slabs, the bonding of fiber reinforced plastic (FRP) plates to the bottom surface is an effective and efficient technique for flexural strengthening. Failure of strengthened members often occurs due to stress concentrations at the FRP/concrete interface. For debonding failure initiated at the bottom of shear or shear/flexural cracks in the concrete, experimental results clearly indicate a progressive failure process accompanied by gradual reduction in shear transfer capability at the interface. Several existing models for FRP debonding have taken interfacial shear softening into account. However, the assumed shear stress versus slip relations employed in the models have never been properly measured. In this investigation, a combined experimental/theoretical approach for the extraction of interfacial stress versus slip relation is developed. With loading applied to a bonded FRP plate, strain is measured at various points along its length. Based on the strain measurements, the interfacial softening curve is derived from a finite element analysis. The present paper will present the proposed approach in detail, demonstrate its application to typical experimental data, and discuss the implications of the results.     

Evaluation of Bond Strength in Concrete Elements Externally Reinforced with CFRP Sheets and Anchoring Devices

Use of anchoring devices can be useful to avoid or delay end debonding failure in reinforced concrete elements externally bonded with fiber-reinforced plastic materials. Many theoretical formulations are now available to predict bond strength, but no design provisions have been suggested to take into account the beneficial effect of anchorage devices. This paper presents the results of experimental bond tests performed on concrete blocks externally strengthened with carbon fiber sheets. The prime focus is the evaluation of effect given by three different types of anchorage systems upon increasing debonding load. A simple model is introduced to predict the influence of the examined anchorage systems on the debonding load. Its accuracy is confirmed by comparisons with the experimental results.     

Identification of Effective Management Practices and Technologies for Lessons Learned Programs in the Construction Industry

Organizations in the construction industry cannot afford to make repetitive mistakes on major projects. Conversely, there are great benefits to repeating positive experiences from past projects. This need for institutional memory is amplified by the reality that in the course of normal turnover and retirement, people with years of experience leave their organizations. An effective lessons learned program is a critical element in the management of institutional knowledge; it will facilitate the continuous improvement of processes and procedures and provide a direct advantage in an even more competitive industry. This paper describes a research study that aimed to identify effective management practices and technologies for lessons learned programs in the construction industry. Data from 70 organizations that participated in this study are presented. Research found that even though more lessons learned programs are being initiated, the potential for savings and improvement has not been fully met. The study has also identified seven crucial characteristics of a successful program and verified that most organizations are stronger in some categories and weaker in others. The key to an effective program is to address all seven areas and guidance is provided for those wishing to implement lessons learned programs.     

Past Perfect: Historical Antecedents of Modern Construction Practices

This paper describes initial research on a project designed to understand the experiences of past generations of constructors and make that knowledge accessible to future generations of engineering students and construction practitioners. Much in the same way as medical students can trace their lineage back to Hippocrates, this project aims to provide architecture, engineering, and construction students, and professionals alike, a sense of their professional history. The project was developed around five time epochs, four geographic regions, and three different project types. We investigated issues such as the flow of money, training of workers, sharing of design knowledge, and nature of contracts and agreements. The central question posed by this work is how should knowledge of the history and evolution of construction practices be incorporated in the dialog that educators have with students and with the larger professional community? This research has led to multifaceted results. On the one hand, the message to students should be pride in their professional heritage because throughout time constructors and designers have used knowledge, perseverance, and innovation to accomplish remarkable projects. On the other hand, we have shown that much of what is considered new in the industry (alternative project delivery methods, worker safety programs, public private partnerships, and globalization) have historical antecedents and are not new at all.     

Three-Stage Least-Squares Analysis of Time and Cost Overruns in Construction Contracts

Construction cost overrun and time overrun (delay) are a significant problem in highway-construction project delivery. Previous research studies have provided insight into the factors that affect overruns; however the findings may have been limited because they do not explicitly consider the simultaneous relationship between cost and time overruns. In this paper, we use data from Indiana highway projects to provide empirical evidence that a simultaneous relationship exists between cost and time overruns and that analysis of these two contractual outputs need to take due cognizance of such simultaneity. Using the three-stage least-squares technique, we identify a number of factors that significantly affect cost overrun and time overrun and we show how the effect of these variables vary by attributes such as project type and results of the bidding process. The models developed in this paper can help agencies enhance the estimation of the expected overruns of final cost and the delay in completion time for their planned projects.     

Benchmarking System for Evaluating Management Practices in the Construction Industry

This paper presents the results obtained for the initial application of a management evaluation system whose objective is to provide a continuous improvement tool for construction companies through benchmarking management practices. The outlined system seeks to support a benchmarking system that has been recently established in the Chilean construction industry by incorporating qualitative management aspects in addition to performance indicators. Different analyses were made to determine trends in the sector and to establish correlations between qualitative aspects coming from surveys and quantitative aspects coming from performance indicators. Thirteen construction companies participated in the initial application of the benchmarking system. A correlation analysis found that safety performance was strongly related to companies having superior planning and control, quality management, cost control, and subcontractor management policies. A factor analysis found that central office priorities focus on strategic management policies having longer-term competitive impact, while site management emphasizes tactical management dimensions having short-term impact. There is scope to elevate the profile of continuous improvement initiatives to strategic significance at the central office level.     

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.     

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.     

Critical Success Factors for Bond Financing of Construction Projects in Asia

Although bonds have been commonly used for financing construction works in developed countries such as the United States, Asian governments would like to see their construction growth increasingly funded by alternative sources such as the capital market, instead of overrelying on bank loans. Yet even in relatively active markets such as Hong Kong and Singapore, the use of bond financing for infrastructure development is limited. In a recent study based on two questionnaire surveys with subsequent interviews about retail and institutional investors, results demonstrated that credit risk was a major concern and that deterrents include lack of bond market information, illiquidity of domestic bonds, and the reliability of external credit ratings. Institutional investors, however, welcome infrastructure bonds because of the stable income stream matching their long-term commitments. To address these practical concerns, we have proposed credit and liquidity enhancement measures in this paper as the critical success factors for international construction promoters to tap into the bond market for financing construction works in Asia. Hence, this paper will be of interest to academics and practitioners who are working on project financing, because empirical findings reveal investors’ concerns, which are then addressed with recommendations.     

Performance Evaluation of Construction Enterprise Resource Planning Systems

To successfully evaluate investments related to integrated information management in the construction industry, causal loop diagramming was used to depict the qualitative system dynamics model for the study of the dynamics of construction enterprise resource planning systems (C-ERP). With the aid of system dynamics principles, together with literature review and two case studies, the major variables that influence the successful evaluation of C-ERP in the construction industry were evaluated. The major variables identified were validated with data from a survey. The validation procedure quantified associations between variables and perceived benefits from C-ERP stakeholders of construction-related firms. The model described in this paper aims at providing a holistic understanding of the C-ERP dynamics in construction. With this model, researchers and industry practitioners can develop an insight into C-ERP investments in practice.     

Visualization of Work Flow to Support Lean Construction

Implementation of advanced production management techniques, such as lean construction concepts like filtering of work packages to stabilize work flows, pull flow of teams and materials, and in-process quality control, demands effective and timely flows of information both to and from the workface. The key requirement—making the process state transparent to all participants—is more difficult to achieve in construction than in manufacturing, because work crews move continuously within a physical environment that is itself changing. Novel computer-aided visualization tools can fulfill the needs that simpler tools, such as Kanban cards, fulfill in manufacturing. Two prototypes with user interfaces designed to facilitate process flow have been devised and implemented within the context of building information modeling (BIM) software systems. They demonstrate aspects of the synergy between BIM and lean construction. Given the dynamic and dispersed physical environments and the fractured contracting arrangements typical of construction, BIM-based visualization interfaces are important tools for providing process transparency.     

Tracking the Location of Materials on Construction Job Sites

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

Evaluation of Legal Risks for E-Commerce in Construction

E-commerce is steadily becoming a reality in the construction industry. However, despite the increasing rate of utilization by owners and contractors alike, the legal implications of using e-commerce in construction have not been studied in depth. This paper fills this gap in literature. It identifies and analyzes the different types of legal risks involved in the use of e-commerce in construction. It also outlines the risk that contractors and professionals may face in their e-commerce implementations. A classification of e-commerce legal risks is also introduced. The legal risks discussed include agency, jurisdiction, contract formation, validity and errors, authentication, attribution, nonrepudiation, privacy, conflict of laws, and conflict between law and technology.     

Contractors’ Views of the Potential Causes of Inconsistencies between Design and Construction in Saudi Arabia

The study identifies the causes of inconsistencies between the design and construction of large building projects. To achieve the study objectives, a questionnaire survey was carried out to collect information on potential causes of inconsistencies at the project design and construction interface. Responses from 27 contractors were analyzed. The results suggest that the involvement of designer as consultant, communication gap between constructor and designer, insufficient working drawing details, lack of coordination between parties, lack of human resources in design firm, lack of designer’s knowledge of available materials and equipment, and incomplete plans and specifications were considered as the most important causes of the project design and construction interface inconsistencies. On the other hand, project management as a professional service, weather conditions, nationalities of participants, involvement of the contractor in design conceptual phase, unforeseen problems, involvement of the contractor in design development phase, and government regulations were the least important causes of inconsistencies between professionals at the project design and construction interface in large building projects.