Infrastructure Engineering - Theses
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ItemDuctility of one-way slabs constructed with class L mesh, Grade 500 steel, under support settlement( 2005)This study investigates the impact of new class L Grade 500 Australian steel on the behaviour of suspended reinforced concrete slabs. An experimental program consisting of two one-way full-scale slabs constructed with class L steel was carried out. The key focus of the test program was to examine the response of slabs under imposed support settlements, which could occur for various reasons in the life of a structure. The experimental results were compared with the numerical results obtained by using the computer software prepared by Dr. Rebecca Gravina at The University of Adelaide, SA. Two continuous one-way slabs, with spans more than 4 m and 5 m respectively, constructed with class L steel were tested under imposed support settlement. A typical value of support settlement was used to raise the intermediate support of one test slab and to lower the intermediate support of the other. The results recorded using various techniques were used to establish the load-deflection curves, moment-rotation curves, degree of moment redistribution, failure loads and crack patterns at different load stages during the tests. A comparison of the experimental results with the numerical study carried out by Dr. Rebecca Gravina using software developed in her PhD studies showed a good agreement between the two results. This study showed that the test slabs were able to resist a load higher than the design load, even when subjected to support settlements of a magnitude expected in practice. Also the test slabs developed significant cracking in the spans as well as over the intermediate support regions before failure. The load deflection curves showed little sign of ductility. Moreover, the failure in each case was in a catastrophic manner by fracture of steel in the negative moment region, with no sign of compressive concrete crushing. This study has provided a detailed experimental investigation about the behaviour of class L steel under support settlement effects. However, it is limited to one-way slabs and has used reinforcement provided one steel manufacturer. It can be further extended to two-way slabs and also to class N steel for comparison with class L behaviour.
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ItemSeismic performance of concrete beam-slab-column systems constructed with a re-usable sheet metal formwork system( 2007)This report describes an investigation of seismic performance of a ribbed slab system constructed with an innovative re-usable sheet metal formwork system. Experimental results from quasi-static cyclic lateral load tests on half-scale reinforced concrete interior beam-slab-column subassemblages are presented. The test specimen was detailed according to the Australian code (AS 3600) without any special provision for seismicity. This specimen was tested up to a drift ratio of 4.0 %. Some reinforcement detailing problems were identified from the first test. The damaged specimen was then rectified using Carbon Fibre Reinforced Polymer (CFRPs), considering detailing deficiencies identified in the first test. The repaired test specimen was tested under a lateral cyclic load as per the original test arrangement up to a drift level of 4%. The performance of the repaired specimen showed significant improvement with respect to the level of damage and strength degradation. The results of the rectified specimen indicate that the use of CFRPs may offer a viable retrofit/repair strategy in the case of damaged structures, where this damage may be significant. Two finite element analysis models were created and results of the first test were used to calibrate the FE model. The second FE model was used to obtain detail information about stress and strain behaviour of various components of the beam-column subassemblage and to check the overall performance before carrying out expensive lab tests. It was concluded that finite element modelling predictions were reliable and could be used to obtain more information compared to conventional type laboratory tests. Time-history analyses show that the revised detailing is suitable to withstand very large earthquakes without significant structural damage.