Record Details
Risk and reliability associated with use and reuse of vertical formwork
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Risk and reliability associated with use and reuse of vertical formwork |
| Names |
Das, Amrutha
(creator) Barbosa, Andre R. (advisor) Gambatese, John A. (advisor) |
| Date Issued | 2014-05-23 (iso8601) |
| Note | Graduation date: 2014 |
| Abstract | Concrete formwork is a common type of temporary structure used on construction projects. Due to difficulties in considering actual construction site implications during formwork design, assessments of formwork integrity are often made in the field by site personnel based on subjective visual inspection. The use and re-use of concrete formwork exposes the workers involved in formwork use to different types of injury. This research study aims at: (i) mapping a general site activity workflow for the use and re-use of vertical formwork; (ii) evaluating onsite safety risks associated with formwork use and re-use activities, and (iii) assessing the reliability associated with formwork use and re-use. Development of the mapped workflow and identification of safety risks associated with each activity were based on interviews of construction site foremen involved in formwork construction and jobsite observations of formwork construction activities. Based on results from the survey on 32 carpenters engaged in concrete work, worker risk associated with formwork activities was quantified. Erection, stripping, and assembly of formwork were found to be activities that contribute most to the cumulative risk. The worker perception on the safety risk was compared to the recorded Occupational Safety and Health Administration (OSHA) Fatality and Catastrophe summaries, which correspond to worker injury reports. Data collected from OSHA injury reports indicate that concrete pouring, erection, and stripping are the activities with the highest risk. This shows a notable disconnect between survey based worker perception results and corresponding OSHA statistics. Sensitivity of unit risk indicate that high severity incidents have the highest impact on the risk, followed by Near Misses. Comparing the capacity of formwork samples with different number of uses to estimated load demand, reliability assessments were performed. The reliability assessment results are mixed since a large bias and uncertainty in the computation of the loading and capacity were identified in the development of this study. The bias is related to overly simplified and over conservative design equations that are currently prescribed in design guides, while the large uncertainty is mainly due to inherent randomness in the material and influence of exposure to the concrete on the strength of the plyform. |
| Genre | Thesis/Dissertation |
| Access Condition | http://creativecommons.org/licenses/by-nd/3.0/us/ |
| Topic | Formwork |
| Identifier | http://hdl.handle.net/1957/49925 |
