Modelling of 3D structures in fire as skeletal frames using the Fire Beam Element (FBE) for simplified analysis and design
| dc.contributor.advisor | Walls, Richard Shaun | en_ZA |
| dc.contributor.author | Strauss, Lourens | en_ZA |
| dc.contributor.other | Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering. | en_ZA |
| dc.date.accessioned | 2021-02-24T12:08:58Z | |
| dc.date.accessioned | 2021-04-21T14:34:14Z | |
| dc.date.available | 2021-02-24T12:08:58Z | |
| dc.date.available | 2021-04-21T14:34:14Z | |
| dc.date.issued | 2021-03 | |
| dc.description | Thesis (MEng)--Stellenbosch University, 2021. | en_ZA |
| dc.description.abstract | ENGLISH ABSTRACT: n recent years performance-based designhasbecomemore popular in structural fire engineeringas itoften leads to more cost effective and safe designs. Real incidents,such as the Broadgate fire in 1990,and large-scale experiments, such as the Cardington tests, have shownthat composite structures havesignificantlyhigher resistance in fire than whatis typicallypredicted by prescriptive designs based on isolated members. However, performance-based design tools require significant expertise and computational effort. Simplified tools,such asthe Fire Beam Element (FBE)methodologyandtheSlab Panel Method (SPM),can individually be used to analyse the skeletal frame of a structure in fire or composite floorpanelsrespectively.However, few tools exist for consulting engineers to be able to comprehensively, but efficiently, consider global structuralanalyses for fire. The FBE methodology is based on a finite element that has a movable Neutral Axis (NA) and can consider material and geometric nonlinearity. In this research the FBE methodology is extended toincludea three-dimensional (3D) beam element andisimplemented in a finite element software, OpenSees, so that it could be applied to 3D skeletal composite structures. The SPM is a design tool for composite slabs that considers the concrete deck and unprotected secondary beams as a whole. In theSPM, the ultimate load-carrying capacity is calculated for the slab panel taking into account the Tensile Membrane Action (TMA) mechanism that develops due to large deformationsof the slab panel.In this thesis, a design methodology is proposed linking the FBE methodology with the SPM. In theproposeddesign methodology,the composite slab and the supporting skeletal structureare consideredas two separate systems which are able to interact with eachother. The3D FBEdesign methodology isvalidated withthree-case studies, obtained in literature,which are used to validatethe behaviour of the supporting skeletal structure. The case-studies show that the 3D FBE is able to capture the behaviour of the structure where the Bernoulli-Euler assumption holds, and typically shows good correlations between FBE and literature supplied deformations. The second case study investigated indicatesthat continuity should be taken into account whendetermining the yieldline pattern and load distribution to the support beams.The third case study highlightsalimitation of the FBE analysisthat is applicablewhen the primary support beams losetheirstrength,and the loads are carried through Membrane Action. Lastly, the FBE and SPM design methodology are applied to a ten-storey office building which provides aproofof concept of the overall design methodology. The results obtained from the FBE analysis demonstrated the behaviour of the supporting skeletal structure and the impact that the rest of the structure hason thesupport beams. The ultimate load-carrying capacity of the slab panel arecalculated with the updated edge deflection determined with the FBE analysisIt is highlighted how SPM predictions can be updated based on improved information regarding perimetersupporting beam deflections. | en_ZA |
| dc.description.abstract | AFRIKAANSE OPSOMMING: In die afgelope jare, het prestasie-gebaseerde ontwerp gewilder geword in struktuur brand ingenieursweseaangesien dit dikwels tot meer koste-effektiewe en veilige ontwerpe lei. Werklike voorvalle, soos die Broadgate-brand in 1990, en grootskaalse toetse, soos die Cardington toetse, het getoon dat saamgestelde strukture aansienlike hoër brandweerstand het as wat tipies voorspel word deur voorskriftelike ontwerpe op geïsoleerde lede. Prestasie-gebaseerde ontwerp hulpmiddels vereis egter beduidende kundigheid en berekeningspoging. Vereenvoudigde hulpmiddels,soos die Brand-Balk Element (FBE) metodologie en die Blad Paneel Metode (SPM) kanop hul eie beurtgebruik word om die skeletraamwerk van ‘n struktuur in brand te of om saamgestelde vloer panele te analiseer. Daar is egter min hulpmiddels vir raadplegende ingenieurs wat in ‘n omvattend, maar doeltreffend, die globale struktuur analise vir brand kan in ag neem.Die FBE metodologie is gebaseer op ‘n eindige element wat ‘n mobiele Neutrale As (NA) het en die materiaal en geometriese nie-lineariteit in ag kan neem. In die navorsing word die FBE metodologie uitgebrei om ‘n drie-dimensionale (3D) balk-element in te sluit en word geïmplementeer in eindige element sagteware,OpenSees, sodat dit toegepas kan word om 3D skelet strukture te analiseer. Die SPM is ‘n ontwerp hulpmiddel vir saamgestelde blaaie wat die betonblad en onbeskermde sekondêre balke as ‘n geheel in ag neem. In die SPM word die lasdraende kapasiteit van die blad paneel bereken deur om die Trekmembraanwerking (TMA), wat veroorsaak word deur die groot vervorming van die blad paneel, in ag te neem. In die tesis word ‘n ontwerp metodologie voorgestel wat die FBE metodologie met die SPM verbind. In die voorgesteldeontwerp metodologie word die saamgestelde blad en die ondersteunings skelet struktuur as twee aparte sisteme geag wat met mekaar kan kommunikeer. Die 3D FBE ontwerp metodologie wat gebruik word om is deur drie gevallestudies, uit die literatuur, bevestig. Die gevallestudies het getoon dat die 3D FBE in staat is om die gedag van die struktuur vas te stel waar die Bernoulli-Euler aannames hou, en dat dit tipies goeie korrelasie toon tussen die FBE en buiging voorsien in die literatuur. Die tweede gevallestudie wat ondersoek was, het getoon dat kontinuïteit in ag geneem moet word wanneer die vloeilyn-patroon en die las verspreiding na die ondersteunings balk bepaal word. Die derde gevallestudie het die beperkings van die FBE analise beklemtoon wanneer die primêre ondersteunings balke hul sterkte verloor en die las deur die Membraanwerking gedra word.Laastens is die FBE en SPM ontwerp metodologie toegepas op ‘n tien verdieping kantoor gebou wat as ‘n bewys van konsep dien vir die algehele ontwerp metodologie. Die resultate van die FBE analise het die gedrag van die skelet struktuur gedemonstreer en die impak wat die res van die struktuur het op die ondersteunings balke. Die lasdraende kapasiteit van die blad paneel word bereken met die opgedateerde rand buigingwat bepaal is met die FBE analise. Dit word beklemtoon hoe die SPM voorspelling opgedateer kan word gebaseer op verbeterde inligting met verband met die omtrekkende ondersteunings balke buiging. | af_ZA |
| dc.description.version | Masters | en_ZA |
| dc.format.extent | 144 pages : illustrations | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/10019.1/109967 | |
| dc.language.iso | en_ZA | en_ZA |
| dc.publisher | Stellenbosch : Stellenbosch University | en_ZA |
| dc.rights.holder | Stellenbosch University | en_ZA |
| dc.subject | Fire Beam Element | en_ZA |
| dc.subject | Slab Panel Method | en_ZA |
| dc.subject | Composite construction | en_ZA |
| dc.subject | Structural engineering | en_ZA |
| dc.subject | Finite elements | en_ZA |
| dc.subject | UCTD | en_ZA |
| dc.title | Modelling of 3D structures in fire as skeletal frames using the Fire Beam Element (FBE) for simplified analysis and design | en_ZA |
| dc.type | Thesis | en_ZA |