טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentWicnudel Amit
SubjectLaser Scanning Based Modeling of Construction Sites for
Tower Crane Blind-Lift Analysis
DepartmentDepartment of Civil and Environmental Engineering
Supervisors Professor Emeritus Aviad Shapira
Professor Sagi Filin
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Interruptions to the crane operator's field of view, which result in what is commonly referred to as "blind lifts," are an inseparable part of the work routine of tower cranes and one of the recognized safety hazards of crane operation. The various means of addressing the problem, such as the use of signalers and vision-aid devices or the consideration of dead spots when planning the location of staging and storage areas, are determined intuitively. This is the result of a lack of quantitative information on blind lifts - both with respect to their rate and their spatial distribution - due to the inherent difficulty in generating such information at any given construction site. This study shows how laser scanning data can be utilized to quantitatively assess blind lifts. The crane operator's field of view is mapped, resulting in a representation of the workspace, which allows the analysis of blind lifts in terms of space and time. The study presents the algorithms required to model the crane's workspace and their implementation on a test site. Manual observations were conducted to examine the crane's work periods in dead areas from a quantitative perspective and their analysis was used to validate the proposed laser-scan-based model. Thus, the ability to capture the geometric relations that characterize the work scene around the tower crane by harnessing the increasingly available laser technology is demonstrated. Additional contribution is offered by the potential of combining the proposed model with a lift path analysis to generate a four-dimensional space-occupancy intensity representation to help in determining safer lift trajectories.