Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams
Includes abstract.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | English |
| Published: |
Department of Civil Engineering
2014
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867613203772473344 |
|---|---|
| access_status_str | Open Access |
| author | Tigeli, Mojabeng |
| author2 | Moyo, Pilate |
| author_browse | Moyo, Pilate Tigeli, Mojabeng |
| author_facet | Moyo, Pilate Tigeli, Mojabeng |
| author_sort | Tigeli, Mojabeng |
| collection | Thesis |
| description | Includes abstract. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/4997 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:24.523Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2014 |
| publishDateRange | 2014 |
| publishDateSort | 2014 |
| publisher | Department of Civil Engineering |
| publisherStr | Department of Civil Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/4997 Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams Tigeli, Mojabeng Moyo, Pilate Beushausen, Hans Civil Engineering Includes abstract. Includes bibliographical references (leaves 91-96). Over the years, the need for repair of reinforced concrete (RC) structures has increased significantly, both for old and new structures. The main cause of structural damage in RC structures is corrosion of reinforcement. Therefore there is a need to understand the effects of corrosion damage on the structural properties of RC members such as stiffness and ultimate capacity in order to develop improved and effective repair strategies that will minimise the risk of further damage and structural failure both in the short and long term. Corrosion reduces the cross-sectional area of steel at the corrosion sites, leading to reduced stiffness and capacity of the structure to carry loading, which may result in structural failure if not detected and repaired or strengthened. This study presents experimental results on the effectiveness of combined repair and strengthening of corrosion-damaged RC beams. Four RC beams 154 mm wide × 254 mm deep × 5000 mm long were tested. Three of the beams were subjected to different levels of accelerated corrosion (using 1000 mA impressed anodic current and 5% NaCl solution) under sustained service loads (2 kN) while one beam acted as a control. All four beams were monitored for deflections during the accelerated corrosion period. The beam dynamic characteristics were assessed at all stages; namely the undamaged stage, 10 % corroded, 15% corroded, exposed reinforcement, patch repaired and finally the CFRP strengthened stage. The three corrosion-damaged beams were patch repaired with a cementitious grout; two of them were strengthened with carbon fibre reinforced polymer (CFRP) laminates in addition to the repair. The effect of damage on the stiffness of the beams was inferred from strain measurements, deflections and dynamic properties (natural frequencies and modal shapes). The effect of patch repair and strengthening on corrosion damaged beams was deduced from the changes in their ultimate capacities. From the deflection measurements measured during the corrosion process, stiffness decreased with the increase in corrosion level. Cracks develop and widen as the level of corrosion increases. The results obtained from dynamic testing consist of natural frequencies, mode shapes and damping ratios. The dynamic results show a drop in natural frequencies due to damage and not much change on the fundamental mode shapes is observed when comparing the modes by the Modal Assurance Criterion (MAC) values. The MAC values did not prove useful in identifying damage or changes in RC beams. The static results reveal that both the stiffness and the ultimate capacity are improved by about 25% and 50% respectively when both patch repair and FRP are applied on a damaged beam. Patch repair on its own improved the stiffness by approximately 5% but did not improve the ultimate capacity. As expected, it can be drawn from the results that the combined effect of both patch repair and CFRP strengthening improves the stiffness and ultimate capacity of the structure. 2014-07-31T10:25:08Z 2014-07-31T10:25:08Z 2010 Master Thesis Masters MSc http://hdl.handle.net/11427/4997 eng application/pdf Department of Civil Engineering Faculty of Engineering and the Built Environment University of Cape Town |
| spellingShingle | Civil Engineering Tigeli, Mojabeng Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams |
| thesis_degree_str | Master's |
| title | Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams |
| title_full | Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams |
| title_fullStr | Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams |
| title_full_unstemmed | Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams |
| title_short | Effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion-damaged RC beams |
| title_sort | effects of structural repair and strengthening on stiffness and ultimate capacity of corrosion damaged rc beams |
| topic | Civil Engineering |
| url | http://hdl.handle.net/11427/4997 |
| work_keys_str_mv | AT tigelimojabeng effectsofstructuralrepairandstrengtheningonstiffnessandultimatecapacityofcorrosiondamagedrcbeams |