Full Text Available
Note: Clicking the button above will open the full text document at the original institutional repository in a new window.
Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data
Thesis (MEng)--Stellenbosch University, 2024.
Saved in:
| Main Author: | |
|---|---|
| Other Authors: | |
| Format: | Thesis |
| Language: | en_ZA en_ZA |
| Published: |
Stellenbosch : Stellenbosch University
2024
|
| Subjects: | |
| Tags: |
No Tags, Be the first to tag this record!
|
| _version_ | 1867614110308368384 |
|---|---|
| access_status_str | Open Access |
| author | Matua, Moses Trevor Mandela |
| author2 | De Koker, Nico |
| author_browse | De Koker, Nico Matua, Moses Trevor Mandela |
| author_facet | De Koker, Nico Matua, Moses Trevor Mandela |
| author_sort | Matua, Moses Trevor Mandela |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MEng)--Stellenbosch University, 2024. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/130589 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA en_ZA |
| last_indexed | 2026-06-10T12:46:49.940Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/130589 Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data Matua, Moses Trevor Mandela De Koker, Nico Way, Andrew Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. Concrete bridges Sustainable engineering Bridges -- Design and construction Bridge management systems Thesis (MEng)--Stellenbosch University, 2024. ENGLISH ABSTRACT: As the bridge stock of much of the world is aging, the evaluation of existing reinforced concrete (RC) bridges with regard to functionality and structural safety is becoming increasingly important. In South Africa, the Struman bridge management system is employed for the sustainable maintenance of RC bridges. The evaluation of reinforced concrete (RC) bridge structures relies on visual inspections, employing a Damage, Extent, Relevance, and Urgency (DER-U) rating system to assess defects in bridge elements. This rating system utilizes a scale of 0-4, assigning scores to various defects identified by bridge inspectors during the inspection of existing bridges. A prioritized list is compiled to rank visually inspected bridges, guided by DER-U ratings, from most severely damaged to least, which aids in the allocation of funds or the need for repairs. Therefore, in order to help state road agencies, evaluate the functionality and structural safety of RC bridges using visual inspection data by inspectors, the primary objective of the research was to establish a methodology for determining reliability levels in existing RC bridges in South Africa using data from visual inspections. This is achieved by correlating the DER-U rating with reductions in decision parameters (e.g. area of tension, shear, or compression reinforcement) resulting from identified defects in existing bridges. These reductions in reliability levels are quantified through models grounded in reliability principles. To assess the impact of defects on bridges, various limit states were identified, including spalling of the beam soffit due to vehicle impact, bending cracks around the mid-span zone of RC beam soffit and web, shear cracks along the RC beam soffit and web near the support ends, and damage from traffic collisions on the bridge pier wall. A demonstrative bridge model was employed, with deterioration applied both at the inspection stage and over time to monitor the influence of these limit states on the reliability of the structure. The reduction in structural capacity was subsequently determined using reliability-based models by varying the reduction in decision parameters in accordance with the identified limit states. The analysis indicated that 𝛽 values obtained at the inspection stage can be used by state road agencies in South Africa as indicators to estimate the structural safety levels of the existing RC bridge stock based on the DER-U condition rating system allocated by bridge inspectors. Additionally, the 𝛽 values obtained the at inspection stage can be used in predicting a reduction in 𝛽 over time, considering the influence of corrosion over the remaining operational life span of the existing RC bridges, based on the assessment using the DER-U condition rating system. The error band generated during the prediction of the decline in the 𝛽 values over time, with the influence of corrosion considered, shows transparency in this research and correctly indicates the variation within the prediction. Additionally, the prediction of the reduction in 𝛽 values over time due to corrosion can help give state road agencies an estimate of when major maintenance needs to be done in consideration of the remaining operational life span of the existing RC bridges. It is important to note that the conclusions drawn from the framework in this study are based on the most typical RC bridge geometry and layout in South Africa. The framework will need to be amended and expanded to be relevant to other bridge/material types. The coefficient of variation (COV), stemming from the subjectivity of assigning DER-U ratings by inspectors, was based on prior research conducted in the USA. Therefore, to accurately account for subjectivity in decision parameter reductions, further research specific to South Africa should be undertaken. AFRIKAANSE OPSOMMING: Gegewe dat die brugvoorraad van ‘n groot deel van die wêreld verouder, word die evaluering van bestaande gewapende beton (RC) brûe met betrekking tot funksionaliteit en strukturele veiligheid al hoe belangriker. In Suid-Afrika word die Struman-brugbestuurstelsel aangewend vir die volhoubare instandhouding van RC-brûe. Die evaluering van RC brugstrukture berus op visuele inspeksies, met behulp van ‘n skade-, mate-, relevansie- en dringendheidstelsel (DER-U) om defekte in brugelemente te beoordeel. Hierdie graderingstelsel gebruik 'n skaal van 0-4, wat tellings toeken aan verskillende defekte wat deur bruginspekteurs geïdentifiseer is tydens inspeksie van bestaande brûe. ‘n Geprioritiseerde lys word saamgestel om visueel geïnspekteerde brûe te rangskik, gelei deur DER-U-graderings, van die ernstigste beskadig tot die minste, wat help met die toekenning van fondse of die behoefte aan herstelwerk. Om staatspadagentskappe te help om die funksionaliteit en strukturele veiligheid van RC-brûe met behulp van visuele inspeksiedata deur inspekteure te evalueer, was die primêre doel van die navorsing dus om ‘n metodologie daar te stel vir die bepaling van betroubaarheidsvlakke in bestaande RC-brûe in Suid-Afrika met behulp van data van visuele inspeksies. Dit word bereik deur DER-U-gradering te korreleer met verlagings in besluitparameters (bv. area van bewapeningstaal) as gevolg van geïdentifiseerde defekte in bestaande brûe. Hierdie verlagings in betroubaarheidsvlakke word gekwantifiseer deur modelle gegrond op betroubaarheidsbeginsels. Om die impak van defekte op brûe te bepaal, is verskeie limiettoestande geïdentifiseer, insluitend afsplintering van die balk-soffiet as gevolg van voertuigimpak, buigkrake rondom die middelspansone van RC-balk-soffiet en web, skuifkrake langs die RC-balk-soffit en web naby die steunpunte, en skade deur verkeersbotsings op die brugkolomme. ‘n Demonstratiewe brugmodel is gebruik, met verswakking wat tydens inspeksiestadium en mettertyd toegepas is om die invloed van hierdie limiettoestande op die betroubaarheid van die struktuur te monitor. Die vermindering in strukturele kapasiteit is daarna bepaal deur gebruik te maak van betroubaarheidsgebaseerde modelle deur die vermindering in besluitnemingsparameters te verander in ooreenstemming met die geïdentifiseerde limiettoestande. Die aneliese het aangedui dat β waardes wat tydens inspeksiestadium verkry is, deur staatspadagentskappe in Suid-Afrika as aanwysers gebruik kan word om die strukturele veiligheidsvlakke van die bestaande RC-brugvoorraad te skat op grond van die DER-U-stelsel wat deur bruginspekteurs toegeken is. Daarbenewens kan die β waardes wat tydens inspeksiestadium verkry is, gebruik word om ‘n vermindering in β met verloop van tyd te voorspel, met inagneming van die invloed van korrosie oor die oorblywende lewe van die bestaande RC-brûe, gebaseer op die assessering met behulp van die DER-Utoestandgraderingstelsel. Die foutband wat gegenereer is tydens die voorspelling van die afname in die β waardes oor tyd, met die invloed van korrosie in ag genome, toon deursigtigheid in hierdie navorsing en dui die variasie binne die voorspelling korrek aan. Daarbenewens kan die voorspelling van die vermindering in β waardes oor tyd as gevolg van korrosie help om staatspadagentskappe ‘n skatting te gee van wanneer groot instandhouding gedoen moet word met inagneming van die oorblywende lewe van die bestaande RC-brûe. Dit is belangrik om daarop te let dat die gevolgtrekkings wat uit die raamwerk in hierdie studie gemaak word, gebaseer is op die mees tipiese RC-bruggeometrie en -uitleg in Suid-Afrika. Die https://scholar.sun.ac.za SU Page | v raamwerk sal gewysig en uitgebrei moet word om relevant te wees vir ander brug- /materiaaltipes. Die koëffisiënt van variasie, wat voortspruit uit die subjektiwiteit van die toekenning van DER-U-graderings deur inspekteurs, is gebaseer op vorige navorsing wat in die VSA gedoen is. Om dus subjektiwiteit in besluitnemingsparameterverlagings akkuraat te verreken, moet verdere navorsing spesifiek vir Suid-Afrika onderneem word. Masters 2024-02-12T06:17:40Z 2024-04-26T23:06:49Z 2024-02-12T06:17:40Z 2024-04-26T23:06:49Z 2024-03 Thesis https://scholar.sun.ac.za/handle/10019.1/130589 en_ZA en_ZA Stellenbosch University xvi, 125 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Concrete bridges Sustainable engineering Bridges -- Design and construction Bridge management systems Matua, Moses Trevor Mandela Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data |
| title | Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data |
| title_full | Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data |
| title_fullStr | Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data |
| title_full_unstemmed | Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data |
| title_short | Framework for the assessment of reliability in existing RC bridges in South Africa using visual inspection data |
| title_sort | framework for the assessment of reliability in existing rc bridges in south africa using visual inspection data |
| topic | Concrete bridges Sustainable engineering Bridges -- Design and construction Bridge management systems |
| url | https://scholar.sun.ac.za/handle/10019.1/130589 |
| work_keys_str_mv | AT matuamosestrevormandela frameworkfortheassessmentofreliabilityinexistingrcbridgesinsouthafricausingvisualinspectiondata |