Mahdi Safa

Quality assurance for high-frequency mechanical impact (HFMI) treatment of welds using handheld 3D laser scanning technology

The idea of using 3D point clouds obtained with the aid of a handheld 3D laser scanner for the quality assurance of high-frequency mechanical impact (HFMI) treatment is proposed and demonstrated in this paper. The effectiveness of impact treatments for extending the fatigue lives of welded structures has been demonstrated in numerous studies. Guidelines for the proper execution of impact treatments have been developed. A lack of suitable quality assurance (QA) procedures for accepting or rejecting the treatment after completion has been previously identified. In contrast with the existing QA procedures, which are based mainly on controlling inputs and visual inspection, a technology-based, quantitative methodology is developed in this paper. Five welded specimens were subjected to impact treatment at various levels to simulate under-, proper, and over-treatment. A handheld 3D laser scanner was then used to facilitate a point cloud-based method to determine the geometric parameters of the treated weld toe groove, which were then measured manually. The results show that the proposed methodology is successful in identifying the different treatment levels. This approach has a number of advantages over the existing QA methods, including the following: providing quantitative measures, ease of use, and archive-ability.

Interface Management Model for Mega Capital Projects

Many construction projects are becoming more complex and large in scale due to advances in technology and operations. These projects involve many stakeholders, with different geographical locations and working cultures, collaborating with one another throughout the project life cycle. Industry leaders believe that interface management systems can be created to improve alignment between stakeholders and reduce project issues and conflicts. However, identifying interfaces and monitoring interface states are significant challenges that creates a continues struggle for owners. Interfaces are generally considered as the links between different construction elements, stakeholders and project scopes. Poor management of interfaces may result in deficiencies in the project cost, time, and quality during the project life cycle execution, or may result in failures after the project has been delivered. Therefore, having systematic interface management to effectively handle the interfaces through the project life cycle is critical to project performance. In this paper, a process based approach is proposed for interface management of mega capital projects, starting with the definition and taxonomy of interfaces. Then, the main steps for implementing an Interface Management System (IMS) are introduced: (1) interface identification, (2) documentation, (3) issuing, (4) communication, and (5) closing.

Data Fusion Process Management for Automated Construction Progress Estimation

AbstractThis paper presents a process management framework for multisensory data fusion for the purpose of tracking the progress of construction activity. The developed framework facilitates the required type of data fusion at any given point in the construction progress, reliably and efficiently. Data are acquired from high-frequency automated technologies such as three-dimensional (3D) imaging and ultrawideband (UWB) positioning, in addition to foreman reports, schedule information, and other information sources. The results of validation through a detailed field implementation project show that the developed framework for fusing volumetric, positioning, and project control data can successfully address the challenges associated with fusing multisensory data by tracking activities rather than objects, a feature that offers superior capability, efficiency, and accuracy over the length of the project. Other contributions of this research include the development of fusion processes that are performed at hi...

An Integrated Quality Management System for Piping Fabrication Using 3D Laser Scanning and Photogrammetry

Addressing deficiencies and defects that occur during construction projects is costly and time consuming. The manual quality assurance programs currently used in the industry have certain limitations, including human error and lack of consistency. Hence, there is a need for integrated electronic models that employ new technologies and methods. This research introduces an integrated construction quality control system that has the potential to improve quality management processes in the construction field for piping construction, which is a complex process often requiring rework. The proposed integrated system relies on data collected from construction sites using photogrammetry and laser scanning, which is then used to compare actual work performed to that designed. The proposed system aims to improve the promptness and accuracy of quality assurance processes, in particular dimension measurements, by avoiding human error and integrating defect detection and quality management. The use of this system has highlighted some of the limitations during data fusion and acquisition process, which are highlighted in this paper. These aspects must be considered to increase the reliability of the acquired information.

Rail corrosion forensics using 3D imaging and finite element analysis

Rail infrastructure renewal maintenance is capital intensive. As a contributor to rail deterioration, corrosion damage needs to be accurately analysed for renewal maintenance planning. The main contribution of this study is to introduce an information-dense forensic analysis method for characterizing rail corrosion damage in situ based on 3D imaging. Two state-of-the-art technologies, an arm laser scanner and handheld laser scanner, are employed for onsite digitization of the rail surface. Acquired 3D image data is analysed to characterize pitting corrosion in terms of volume, surface area coverage and average pit depth. Cyclic loading of the sampled rail is simulated using finite element analysis of the 3D image to establish risk potential for crack initiation. A case project was used to validate the feasibility of the developed approach. The results of this study demonstrate the usefulness of applying forensic methodology to renewal maintenance planning.

Automated Registration of 3D Point Clouds with 3D CAD Models for Remote Assessment of Staged Fabrication

Modularization and pre-assembly are parts of a trend toward staged fabrication that has been developing in the construction industry in many parts of the world over the past few decades. Successful delivery and transportation of materials in staged fabrication processes has always been a key challenge. While substantial advances in modularization and pre-fabrication have been achieved recently, there is still a significant rate of damages and defects occurring during transportation and shipment. In addition, there are inaccuracies in staged-fabricated assemblies due to manually intensive quality control during the fabrication process. Thus there is a significant need to continuously monitor the fabrication processes to avoid significant rework costs and delays. This paper presents an automated approach to register laser scanned data, which represents as-built status, with 3D CAD models for prefabricated steel assemblies. Moreover, automated registration enhances three-dimensional tolerance analysis for automated quality control of prefabricated assemblies. An Iterative Closest Point (ICP)-based model is used for automated registration in the presented paper. An experimental study is conducted to validate the proposed model for monitoring the fabrication and installation processes. Experimental results show that the presented approach can be used to detect defected parts or fabrication inaccuracies precisely and quickly.

Predicting Energy Usage Using Historical Data and Linear Models

This paper presents a method to predict energy usage, based on weather conditions and occupancy, using a multiple linear regression model (MLR) in research office buildings. In this study, linear regression models of four research office sites in different regions of New Zealand were selected to show the capability of simple models to reduce margins of error in energy auditing projects. The final linear regression models developed were based on monthly outside temperatures and numbers of full time employees (FTEs). Comparing actual and predicted energy usage showed that the models can predict energy usage within acceptable errors. The results also showed that each building should be investigated as an individual unit.

Front End Planning Tool (FEPT) Based on an Electronic Process Management

Research indicates that good front-end planning (FEP) results in the achievement of higher levels of project performance. By facilitating collaboration among stakeholders in diverse locations with the use of workflow-enabled processes, such pressures can be reduced, and the overall process and results of FEP can be improved. With these goals, a front-end planning tool (FEPT) has been developed as support for owners and major contractors who are engaged in front-end planning. This paper presents the new FEPT and describes how it has been used for construction megaprojects in the nuclear power, oil and gas, and mining industries. The paper begins with the definitions related to and an explanation of the general process for implementing and applying the FEPT and then describes and analyzes how the FEPT was applied in case study projects in order to test its validity. The results indicate that the FEPT increases the efficiency and effectiveness of front-end planning for the megaprojects studied and that it has the potential to produce similar results for other megaprojects.

Construction contract management using value packaging systems

In large construction projects, optimally dividing, packaging, and awarding the work amongst contractors and suppliers can be challenging. Typically, this procurement process is executed in the pre-construction phase based on the experience and judgement of the project leadership team. Once procurement is completed, it is difficult to demonstrate whether the results of this process are optimal, or to explain the rationale behind decision making. An auditable and robust method is needed to address these issues, while still taking into account the expertise of the project leadership team. Thus, a comprehensive construction value packaging system (CVPS) is presented which serves as a computational and process environment for assisting project leaders by increasing the efficiency, auditability, and effectiveness of the procurement process. The development of this system requires a new concept to be defined, the construction value unit (VU), whose scope covers value-added work defined by type of activity, its stage in the value chain, and its specifications. Construction value packages are composed of VUs. Research findings demonstrate that the VPS has the potential to improve the contract management of an enterprise-wide construction supply chain.

Optimizing Contractor Selection for Construction Packages in Capital Projects

AbstractIn capital construction projects, the contractor selection process is executed in the front-end planning phase based on the experience and judgment of the project leadership team, whose members are considered experts. A comprehensive construction value packaging system (CVPS) is presented for assisting these project leaders in improving the efficacy, efficiency, and transparency of this process. The CVPS comprises an interface-oriented approach to work decomposition and a multicriteria approach to contractor selection. Selection is supported by software for iteratively computing and interactively visualizing the Pareto front of optimal work packages. The CVPS is validated by functional demonstration and a case study of a piping installation project in an energy infrastructure facility. The initial Pareto front had more than 100,000 optimal work packages representing different trade-offs between cost, time, contractor experience, maintenance rates, and financial stability. An iterative and interact...