Design of modified steel shipping containers for ambient and elevated temperatures

Oosthuysen, Christian (2022-04)

Thesis (MEng)--Stellenbosch University, 2022.

Thesis

ENGLISH ABSTRACT: The use of shipping containers as basic building blocks for commercial and domestic buildings is fast becoming a popular method of construction. There are numerous reasons why shipping containers are gaining popularity while the biggest drivers are linked to cost, architectural freedom and time of construction. The primary goal of this thesis is to determine the structural resistance of load bearing elements in shipping container buildings at both ambient and elevated temperatures. The reduction in capacity of the main load bearing elements, namely the corner columns, were associated with the removal of the corrugated wall panels. An upper and lower bound capacity was determined for each corner column by considering the sheeting to be fully present and entirely absent respectively. The load bearing capacities for the back and front corner columns were 958 and 923 kN respectively for the upper bound capacity and were in good agreement with capacities determined previously according to experimental testing. A reduction in capacity of 20 and 34% occurred for the back and front corner columns for the lower bound scenario considered. Previous authors have shown that the corrugated sheeting provides significant lateral rigidity while the results from this thesis emphasise the significance of the corrugated sheeting with respect to the load bearing capacity of the main load bearing elements. The Euler buckling capacity of the shipping container side wall was found to be 317 kN due to a monolithic load applied to the top support beam. Inclusion of plasticity in the material definition led to failure of the top side beam. Even though these capacities are considered sufficient with regard to the design loads of many shipping container building configurations, a method of strengthening the side wall was proposed by increasing the stiffness of the surrounding members and adding stiffeners at the positions of expected bearing failure. The load bearing capacities of the corner columns reduced at an unprecedented rate when exposed to the ISO 834 standard fire curve for the unprotected case. The fitting of passive fire protection boards reduced the rate of capacity reduction considerably while even after a 2-hour standard fire exposure the corner columns were found to have considerable residual capacity. For 20 mm thick boards, the capacity of the back and front corner columns reduced by 24 and 13%. To ensure the reduced capacities of the corner columns are not exceeded it is important to prevent high thermally induced forces from occurring by permitting thermal expansion. Assuming the boards do not fail according to the integrity criteria and that thermal expansion is allowed for, the corner columns are considered to have adequate load bearing capacity to resist design loads typical for modular construction.

AFRIKAANSE OPSOMMING: Die gebruik van skeepshouers as basiese boublokke vir kommersiële en huishoudelike geboue is vinnig besig om 'n gewilde konstruksiemetode te word. Daar is talle redes waarom skeepsvraghouers gewild raak terwyl die grootste dryfvere gekoppel word aan koste, argitektoniese vryheid en tyd van konstruksie. Die primêre doel van hierdie tesis is om die strukturele weerstand van lasdraende elemente in skeepsvraghouergeboue by beide omgewings en verhoogde temperature te bepaal. Die vermindering in kapasiteit van die hoofdraende elemente, naamlik die hoekkolomme, is geassosieer met die verwydering van die geriffelde muurpanele. 'n Boonste en onderste bindingskapasiteit is vir elke hoekkolom bepaal deur die velle onderskeidelik ten volle teenwoordig en heeltemal afwesig te beskou. Die dravermoë vir die agterste en voorste hoekkolomme was onderskeidelik 958 en 923 kN vir die boonste grenskapasiteit en was in goeie ooreenstemming met kapasiteite wat voorheen volgens eksperimentele toetsing bepaal is. 'n Vermindering in kapasiteit van 20 en 34% het voorgekom vir die agterste en voorste hoekkolomme vir die ondergrens-scenario wat oorweeg is. Vorige skrywers het getoon dat die sinkplate beduidende laterale styfheid bied, terwyl die resultate van hierdie tesis die belangrikheid van die sinkplate met betrekking tot die dravermoë van die hoof-draende elemente beklemtoon. Die Euler-knikvermoë van die skeepshouer se sywand was 317 kN as gevolg van 'n monolitiese las wat op die boonste steunbalk toegepas word. Insluiting van plastisiteit in die materiaaldefinisie het gelei tot mislukking van die boonste sybalk. Selfs al word hierdie vermoëns as voldoende beskou met betrekking tot die ontwerpladings van baie skeepshouerboukonfigurasies, is 'n metode om die sywand te versterk voorgestel deur die styfheid van die omliggende lede te verhoog en verstewigings by te voeg by die posisies van verwagte laerfaling. Vir die onbeskermde omhulsel het die dravermoë van die hoekkolomme teen 'n ongekende tempo verminder toe dit aan die ISO 834-standaardbrandkurwe blootgestel is. Die aanbring van passiewe brandbeskermingsborde het die tempo van kapasiteitsvermindering aansienlik verminder, terwyl selfs na 'n 2-uur standaardbrandblootstelling is daar gevind dat die hoekkolomme aansienlike residuele kapasiteit het. Vir 20 mm dik borde is die kapasiteit van die agterste en voorste hoekkolomme met 24 en 13 % verminder. Om te verseker dat die verminderde kapasiteit van die hoekkolomme nie oorskry word nie, is dit belangrik om te verhoed dat hoë termies-geïnduseerde kragte voorkom deur termiese uitsetting toe te laat. Met die veronderstelling dat die borde nie misluk volgens die integriteitskriteria nie en dat termiese uitsetting toegelaat word, word die hoekkolomme beskou as voldoende in terme van dravermoë om ontwerpladings tipies vir modulêre konstruksie te weerstaan.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/124693
This item appears in the following collections: