- Numerical simulation of shear wall failure mechanisms
- F. Dashti ; R.P. Dhakal ; S. Pampanin
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Structural Analysis ; Earthquake engineering
- Keywords: shear walls ; failure mode ; numerical simulation
- Description
- This study investigates the ability of a finite element model in predicting nonlinear behavior and failure patterns of RC structural walls. Experimental results of walls with different shear-span ratios which failed in different modes are used for
verification. The walls are modelled in the finite element analysis program DIANA9.4.4.
Curved shell elements with embedded bar elements are used to simulate the reinforced concrete section of the walls to be analysed. This type of model does not require ‘plane sections to remain plane’ along a wall, and simulates the in-plane axial-flexure-shear
interaction without requiring any empirical adjustment. The model is found to capture the
monotonic and cyclic responses of the tested wall specimens with reasonable accuracy in terms of hysteresis curves and failure patterns. The failure patterns simulated by the model include shear, flexure, flexure-shear and flexure-out of plane modes depending on different parameters particularly shear-span ratio of the specimens. Moreover, the strain profile captured by the model was in good agreement with experimental measurements indicating that in addition to the overall global response predictions, local behaviour of the wall models can be predicted reasonably well.
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- Preliminary experimental verification of current content sliding modelling techniques
- T.Z. Yeow ; G.A. MacRae ; R.P. Dhakal ; B.A. Bradley
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Earthquake engineering
- Keywords: shake table testing ; friction coefficient
- Description
- Most analytical studies focusing on the sliding of building contents usually make an assumption that the friction force-sliding displacement behaviour is elasto-plastic (e.g. friction coefficient remains constant during sliding). This preliminary study uses experimental data to verify if this assumption is reasonable. Shake table tests of a desk on common flooring materials were conducted to investigate the factors influencing friction behaviour, and to observe the behaviour of the contents under sinusoidal motion. Up to a 15% decrease in friction coefficient was observed with either an 80% increase in mass or a 20 times decrease in relative velocity, indicating that the friction coefficient is dependent on these two parameters. A comparison of the experimental and analytical sliding response of the desk under a single sinusoidal loading pattern on carpet flooring was conducted. Results show that the displacement amplitude of a single sliding excursion and the general sliding trend is well approximated using the elasto-plastic assumption. As such, despite the dependence of friction coefficient on sliding mass and velocity, the elasto-plastic behaviour assumption appears to be reasonable for the sinusoidal loading pattern examined in this paper.
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- Seismic performance of suspended ceilings: Critical review of current design practice
- A. Pourali ; R.P. Dhakal ; G.A. MacRae
- Book Title / Journal: New Zealand Society for Earthquake Engineering (NZSEE) Annual Technical Conference
- Year: 2014 , Volume: , Series:
- Earthquake engineering
- Keywords: Seismic performance ; suspended ceilings
- Description
- Recent experiences have shown that ceiling damage can result in property and functionality loss, injury or even death. This can occur at levels of shaking smaller than those required to produce noticeable structural damage. Despite their frequent use in
New Zealand, many suspended ceilings that experienced damage in the past earthquakes lacked either proper seismic design or efficient installation. There is also an increasing concern about the inconsistency of the limit state applied for the design of ceilings.
This study looks into the gaps and issues currently present in the seismic design and installation of suspended ceilings in New Zealand. In order to provide an inclusive background, the existing standards and guidelines for design and installation of ceilings both available in New Zealand and worldwide have been reviewed. Through this
comparative study, areas of similarity and discrepancy have been identified, along with
the ambiguities and gaps which define the extent of research required. Investigations have also been performed on the seismic design approaches of proprietary suspended ceilings. This study mainly addresses the residential and commercial suspended ceilings provided by two major ceiling manufacturers in New Zealand. The capacity of either ceiling
system has been evaluated through component based fragility studies. The comparison of the current systems’ capacity with the New Zealand code prescribed demand provides an objective understanding of the performance of the existing system. Moreover the efficiency of the assigned design limit states can be better evaluated.
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- Modelling the Fire Resistance of Prestressed Concrete Floors using Multi-Spring Connection Elements
- J.K. Min ; R.P. Dhakal ; P.J. Moss ; A.H. Buchanan ; A.K. Abu
- Book Title / Journal: Journal of Structural Fire Engineering
- Year: 2012 , Volume: 3 , Series:
- Structure types ; Concrete structures
- Keywords: Fire resistance
- Description
- The fire resistance of precast prestressed concrete floor systems is heavily influenced by the end connections and the stiffness of the surrounding structure, both of which must be considered in any analysis. Analysing floor slabs with beam or shell elements whose end nodes share the nodes of supporting beams leads to a major problem for precast prestressed flooring systems where the steel tendons terminate at the end of the flooring
units, because the approach of sharing nodes of the supporting beam and floor assumes that these tendons are anchored into the supporting beams. In order to solve this problem, a “multi-spring” connection element has been developed. Experimental data available from previous research work has been used to validate the finite element model. It is concluded that the inclusion of the multi-spring connection results in more accurate
predictions of prestressed hollowcore slab behaviour in fire conditions.
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- The influence of pounding on member demands in low rise buildings.
- G.L. Cole ; R.P. Dhakal ; A. Carr ; D.K. Bull
- 2012 New Zealand Society of Earthquake Engineering Conference, Paper 026.
- Book Title / Journal:
- Year: 2012 , Volume: , Series:
- Earthquake engineering
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- Case Studies of Observed Pounding Damage during the 2010 Darfield Earthquake.
- Erol Kalkan ; Anil K. Chopra ; Erol Kalkan ; Anil K. Chopra ; Erol Kalkan ; Anil K. Chopra ; Erol Kalkan ; Anil K. Chopra ; Barry J. Davidson ; Anthony P. McBride ; R.P. Dhakal ? G.L. Cole ; D.K. Bull
- Proceedings of the Ninth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Society, Auckland, New Zealand, Paper 173.
- Book Title / Journal:
- Year: 2011 , Volume: , Series:
- Earthquake engineering
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- Building Seismic Ceiling Fragility using Spectral Acceleration.
- J. Singh ; R.P. Dhakal ; S. Pampanin ; G.A. MacRae
- Proceedings of the Ninth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Society, Auckland, New Zealand, Paper 063
- Book Title / Journal:
- Year: 2011 , Volume: , Series:
- Earthquake engineering
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- Development of typical NZ ceiling system seismic fragilities.
- G. Paganotti ; R.P. Dhakal ; G.A. MacRae
- Proceedings of the Ninth Pacific Conference on Earthquake Engineering Building an Earthquake-Resilient Society, Auckland, New Zealand, Paper 116.
- Book Title / Journal:
- Year: 2011 , Volume: , Series:
- Earthquake engineering
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- The fire behaviour of multi-bay, two-way reinforced concrete slabs
- P.J. Moss ; G. Wang ; A.H. Buchanan ; R.P. Dhakal
- Engineering Structures, 30(12), pp. 3566-3573. University of Canterbury. Civil and Natural Resources Engineering
- Book Title / Journal:
- Year: 2008 , Volume: , Series:
- Structure types ; Concrete structures
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- Detailing of Plastic Hinges in Seismic Design of Concrete Structures.
- R.P. Dhakal
- ACI Structural Journal, Vol. 105, No. 6, pages 740-749.
- Book Title / Journal:
- Year: 2008 , Volume: , Series:
- Structure types ; Concrete structures
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