Ossama Salem

Modeling Failure of Wastewater Collection Lines Using Various Section-Level Regression Models

AbstractWastewater utilities are aiming to implement asset management strategies to minimize costly emergency repairs, to justify expenditures, and to optimize future renewal actions. Consequently, development of deterioration models that explain the behavior of wastewater lines and provide predictions regarding potential future condition levels is gaining importance. In this paper, deterioration models are generated to estimate the probability of failure values for sewer sections. A set of variables was obtained by examining the inventory and inspection databases of a sewer network. Three statistical methods (ordinal regression, multinomial logistic regression, and binary logistic regression) were employed in successive steps. Proportionality of odds assumption was tested for ordinal regression models, and suitability of this particular method was discussed. Estimated condition ratings were compared with observed data, and the binary logistic regression model was found to be more suitable for predicting ...

Psychosocial factors and musculoskeletal disorders in the construction industry: a systematic review

Background: Recent reports indicate that construction workers are at a significant risk of musculoskeletal disorders. While there are several reviews investigating the association between psychosocial factors and musculoskeletal disorders, there are none focusing on those specific to the construction industry. Objective: To review and critically appraise the current epidemiological literature linking psychosocial work factors to musculoskeletal disorders among construction workers. Methods: An online search of relevant databases was conducted. The quality of identified articles was assessed using a quality scoring checklist. The evidence from selected studies was summarized and the results of the critical appraisal were discussed. Results: Eight cross-sectional and two cohort studies were included in this review. High job stress was the most commonly investigated factor followed by job satisfaction, job control and high quantitative job demands. All studies reported an association between musculoskeletal disorders and at least one psychosocial factor. Many of the associations reported were significant even after adjusting for demographics and physical demands of the job. Conclusion: Despite some methodological concerns discussed in this review, there is evidence that psychosocial factors are associated with musculoskeletal disorders. This information is essential to the construction industry since most intervention programmes focus only on the physical demands of the job.

QUANTITATIVE ANALYSIS AND COMPARISON OF TRAFFIC DISRUPTION USING OPEN-CUT AND TRENCHLESS METHODS OF PIPE INSTALLATION

The paper presents a summary of the costs of traffic disruptions due to the method of pipe installation chosen for utility construction. The study is limited to university campus projects, and the estimated costs of delay reflect only the time delay and fuel expense. The cost of travel would be more on roadways with high traffic volume, such as freeways and arterial roads. Also, the data and cost estimates do not include business loss and pollution costs. The paper focuses on the social cost considerations in evaluating the comparison of open-cut construction compared to trenchless methods of pipe installation. Based on the data from the case studies and literature review of similar existing studies, the information can be applied to a range of applications in utility construction.

Risk Assessment of Wastewater Collection Lines Using Failure Models and Criticality Ratings

AbstractBecause of deteriorating condition levels of wastewater networks and financial constraints, sewer agencies are seeking methods to prioritize inspection of sewer pipes on the basis of risk of failure. Risk assessment of sewer pipes requires integration of the probability and consequences-of-failure values in a way that reflects the decision maker’s perception of risk. This paper presents the use of a weighted scoring method to determine criticality of sewer pipelines. The procedure involves identifying important factors, determining the relative importance of the selected factors, and summarizing the overall performance of sewer pipes in terms of these factors. Determination of risk of failure by combining the resultant consequence-of-failure values with the probability-of-failure values using simple multiplication, risk matrices, and fuzzy inference systems is presented. Application of these methods is illustrated by using the sewer network information obtained from a local wastewater agency. The ...

Lean techniques in the management of the design of an industrial project

AbstractLean production techniques developed by Toyota Motor Corporation have been widely applied in the manufacturing sector to reduce waste, ensure just-in-time delivery, create effective value streams, and ensure continuous improvement. Over the last two decades, significant efforts have been made to develop the theoretical foundation and practical tools to implement these techniques in the construction process. The construction process is similar to production, in that it involves the assembly of raw materials into a product. The design process, on the other hand, involves conversion of the client’s requirements into manufacturing instructions using creativity and technical knowledge. This makes it challenging to implement the principles of lean production directly to design. This technical note presents the techniques used by a midsize industrial construction contractor: purpose built facility, making decisions at the last responsible moment, lean audits, and 5S in the design of industrial projects t...

Analysis of the Higher-Order Partial Correlation between CII Best Practices and Performance of the Design Phase in Fast-Track Industrial Projects

AbstractA fast-track project delivery strategy is designed to leverage the ability to execute the design, procurement, and construction phases simultaneously to substantially reduce the overall project duration. The successful execution of the design phase in fast-track projects is especially challenging because the concurrent execution of design and construction interferes with the inherently iterative nature of the design process. In this research, it was hypothesized that a correlation exists between the use of some of the Construction Industry Institute (CII) best practices and the performance of design phase in fast-track projects. Analysis of the performance of the design phase in 31 fast-track projects revealed a statistically significant correlation between performance of the design phase and front-end planning, alignment, constructability, and change management. The results of quantitative analysis are supported by qualitative analysis of data, opinion of experts from industry, and academia. The ...

Multi-criteria decision-making system for selecting an effective plan for bridge rehabilitation

The managers of the US transportation infrastructure face the challenge of restoring the aging highway infrastructure system and making it perform more reliably, safely and efficiently at minimum cost and with minimum disruption. The process selection of an appropriate construction plan for rehabilitation/reconstruction of a bridge requires its evaluation on the basis of qualitative and quantitative metrics such as construction cost, effect on surrounding businesses and communities and the flow of traffic, etc. Traditional decision-making methods that are focused on costs alone are not equipped to address the multi-objective nature of the decision-making process. This article presents an example demonstrating a decision-making system based on the analytical hierarchy process that can be utilised to transparently extract quantitative weights which reflect the relative importance of both qualitative and quantitative objectives of a project and select a bridge construction plan that best meets the objectives.

Use of Trenchless Technologies for a Comprehensive Asset Management of Culverts and Drainage Structures

Due to an aging and rapidly deteriorating transportation infrastructure, agencies are facing the challenge of making quick and reliable decisions regarding the repair and renewal of their assets. While comprehensive asset management strategies have been developed for the visible components of the highway system, such as bridges and pavement, culverts and drainage structures are often neglected. The investigators recently completed an MRUTC project in which they have investigated the current culvert asset management practices of transportation agencies and also developed the inventory and inspection protocols necessary for establishing an effective culvert asset management program. This study builds upon the findings of the previous research project and focuses on the application of trenchless technologies for inspection, construction, repair and renewal of culverts. A literature search, a survey of departments of transportation and a survey of technology providers have been conducted to identify and characterize trenchless technology methods used for buried pipes. The limitations of trenchless technologies in terms of applicability to culverts are investigated. Steps of establishing a comprehensive culvert asset management strategy are identified. Based upon the findings a decision support system is developed which will help the decision makers identify the optimum repair/renewal procedures as a function of the condition of the culvert.

User costs in pavement construction and rehabilitation alternative evaluation

The decision-making processes used by many state transportation agencies in US and Canada for selecting a strategy for pavement rehabilitation primarily depend on initial construction and maintenance costs for identifying the most economically efficient pavement rehabilitation alternative. While this approach is appropriate for optimally allocating increasingly limited funds in the face of increasing investment backlog, it is not economically efficient because it does not account for user costs. Despite a significant body of research, the state transportation agencies are hesitant to include user costs in their pavement life-cycle cost analysis processes because of a lack of availability of standard method of calculating user costs. This article presents the results of a study conducted to review the pavement alternative selection processes used by the Ohio Department of Transportation and recommend ways to include user costs in the decision-making process. Incorporating user costs in the decision-making processes right from project-development phase will help transportation agencies stay focused on the customer and minimise overall impact of rehabilitation of the highway system.

Culvert Asset Management Practices and Deterioration Modeling

Drainage infrastructure systems and culverts constitute an important portion of highway assets that require routine inspections, maintenance, and timely repair and renewal. Variations in structural characteristics (i.e., material type, shape, and dimension), environmental exposure, and wide geospatial distribution of these infrastructure assets accompanied with strict budget restrictions pose significant challenges for transportation agency officials. Deterioration models constitute one of the most essential components of any infrastructure asset management strategy; these models provide insight on the significant factors that affect infrastructure condition states and expected behavior of infrastructure assets under different conditions. The objectives of this study are to provide a review of previous studies on factors that affect culvert performance and durability and those on culvert asset management, to present current practices of transportation agencies with regard to management of culverts, and, last, to present development of a preliminary deterioration model that will allow decision makers to identify significant factors that affect deterioration of metal culverts and prioritize inspection procedures. The preliminary deterioration model presented in this study is developed by employing binary logistic regression with a forward stepwise variable selection method on data obtained from the Ohio Department of Transportation.