Ming-Fung Francis Siu

Combining photogrammetry and robotic total stations to obtain dimensional measurements of temporary facilities in construction field

BackgroundThree-dimensional (3D) modeling and visualization of temporary site facilities is instrumental in revealing potential space conflicts and refining time and cost estimates. This research focuses on implementation of photo-based 3D modeling in a time-dependent, dynamically-changing context.MethodsWe propose a cost-effective modeling technique to obtain dynamic dimension measurements of a moving object. The methodology resulting from integrating photo-based 3D modeling and robotic total station tracking technologies better caters to the application needs of visualization and measurement in construction that are critical to operational safety and structural accuracy. The computational foundation of photogrammetry is first addressed then the modeling procedure and the system design described.ResultsIn a module assembly yard, a rigging system being lifted by a mobile crane was identified as the moving object. The length and the length changes of twelve slings on a newly-engineered rigging system at different stateswere measured in order to ensure quality and safety.ConclusionThe proposed technique relies on utilizing two robotic total stations and three cameras and provides a simple, safe and effective solution to monitor the dimensional changes of a temporary facility in the construction field.

Zero-One Programming Approach to Determine Optimum Resource Supply under Time-Dependent Resource Constraints

AbstractSkilled labor is critical to any construction project. The determination of optimum resource supply quantities over different project time periods compounds the resource-constrained project scheduling problem, which has yet to be formally formulated and analytically solved. Previous related research endeavors focused on the allocation of finite quantities of resources in order to arrive at the shortest total duration for a project. The proposed mathematical model is based on the modeling strategy underlying the zero-one programming approach, aiming to generate the optimum resource-constrained schedule under time-dependent resource constraints. Furthermore, a two-stage solution framework is devised to align with critical decision-making processes in current practices of project scheduling and workface planning. The resulting optimum schedule shortens total project duration while streamlining resource supply for each specified time period. An industrial turnaround project serves as the test bed to (...

Scheduling simulation-based techniques for earned value management on resource-constrained schedules under delayed scenarios

Earned value management (EVM) is widely utilized for project progress monitoring and cost control purposes. However, traditional EVM techniques are intended for ideal scheduling scenarios without considering the effect of activity-level and project-level delays. The EVM fails to account for dynamic changes of project status in terms of project time extension and associated cost overrun, potentially generating misleading project performance tracking indicators. This research proposes a refined EVM approach based on discrete event simulation (scheduling simulation) to tackle complicated resource-constrained scheduling. A case study is used to demonstrate its applications on a resource-constrained schedule under postulated delay scenarios. It is found that this approach is conducive to truthfully reflecting the project performance status given a resource-constrained schedule subject to complicated activity-project delay. Conclusions are drawn by recapitulating the research contributions and addressing the limitations in the end.

Methodology for Crew-Job Allocation Optimization in Project and Workface Scheduling

Existing resource scheduling methodologies are insufficient for controlling workflows for individual craft persons in project and workface planning. In practice, the workflow of an individual resource is assigned by a project manager in consideration of the resource supply and resource demand for particular time periods of the project duration. This research study proposes a crew-job allocation methodology to facilitate scheduling and resource management at both project and workface levels. We propose the use of a mathematical model to formulate and solve for the identified problem factoring in resource-time tradeoff options on individual activities. Then a crew-job interaction table is instrumental in visualizing the optimum resource-loaded schedule, which features the shortest project duration and the leanest resource supply under time-dependent resource constraints. Case studies are given to illustrate application of the proposed methodology. This technique potentially provides analytical decision support for not only making cost-effective resource-loaded schedules, but also facilitating the controllability of schedule execution.

Bi-level project simulation methodology to integrate superintendent and project manager in decision making: shutdown/turnaround applications

The critical path method (CPM) provides the standard approach to scheduling construction projects. Limited crew resources compound CPM analysis by imposing resource availability constraints. However, there is no generalized methodology yet to quantitatively determine the optimal quantities of resources to execute specific work packages based on CPM analysis. Furthermore, in project evaluation and review technique (PERT) simulation, the occurrence of uncertain events is represented by probability distributions for activity durations in an implicit fashion. In this paper, a bi-level project simulation methodology is proposed to (1) determine the optimal resource quantities and activity times for each work package and (2) estimate total project duration and man-hour budget at the upper level for project planning through Monte Carlo simulation, based on defining a limited quantity of likely scenarios for each work package. An industrial plant shutdown and turnaround project serves as case study to illustrate application of the proposed methodology.

Simulation of mobile falsework utilization methods in bridge construction

Scaffolds and shoring systems are generally referred to as the falsework in bridge construction, serving as temporary structures to support bridge span construction. The falsework cost usually accounts for 50-70% of the total project concrete budget. Falsework installation and advancing methods can greatly impact the completion time and actual cost. Thus, simulation can be instrumental in planning bridge construction operations and analyzing various options by evaluating postulated “what-if” scenarios. This study uses a previously constructed bridge in Sweden as a case study to test three feasible construction sequence alternatives. One of these alternatives was implemented on the actual construction of this bridge. Modeling was performed in Simphony, which captures the unique construction sequence requirements and constraints, resulting in project durations for each alternative. Results from simulation experiments were corroborated by the construction engineer who had worked on the bridge project in terms of the advantages that each alternative method possesses.

Quantitative Assessment of Budget Sufficiency and Resource Utilization for Resource-Constrained Project Schedules

AbstractAssessment of budget sufficiency and resource utilization for a resource-constrained project schedule is crucial to ensure practical feasibility of the schedule and successful delivery of a construction project. This paper proposes a quantitative assessment approach for characterizing budget sufficiency and resource utilization for a resource-constrained project schedule in an objective fashion. The budgeted unit, deployed unit, and scheduled unit in connection with a resource-constrained project schedule are first defined. Next, two budget sufficiency metrics, named the budget sufficiency index and budget sufficiency variance, are defined for measuring the sufficiency of control budget in terms of deploying resources to execute the project schedule with resource constraints. In addition, two resource utilization metrics, termed the resource utilization index and resource utilization variance, are defined for indicating utilization efficiency of deployed resources based on the schedule. The propos...

Strategies for Optimizing Labor Resource Planning on Plant Shutdown and Turnaround

The complexities inherent in scheduling the execution of process plant turnaround projects present distinctive challenges to project managers in identifying the shortest project duration while determining the optimum crew size. In collaboration with a major plant turnaround contractor in Alberta, we monitored the execution of an oil refinery turnaround project. We looked into management processes in regards to turnaround project schedules development and skilled-labor resource allocation. This research conceptualizes a labor resource provision optimization methodology in the complex and dynamic context of turnaround scheduling, in order to objectively quantify and reduce the crew-size. The optimum quantities of specialty trades to be employed in the field can be objectively determined so as to staff a crew with sufficient skilled-labor resources while also minimizing the duration in executing a turnaround work package.

Operation Effort Optimization for Planning Performance-Based Snow-Removal Projects

AbstractBid proposals for performance-based snow-removal projects are evaluated based on estimated operation efforts and service areas of proposed shop locations and quantities. Dispatch shop locat...

Modified Stepwise Regression Approach to Streamlining Predictive Analytics for Construction Engineering Applications

AbstractA literature review has identified the absence of a robust framework that guides the development of streamlined and valid multiple linear regression (MLR) predictive models for construction...