- An Experimental Study on the Out-Of-Plane Stability of Reinforced Masonry Shear Walls Under In-Plane Reversed Cyclic Loads
- N. Azimikor ; B. Robazza ; K. Elwood ; D.L. Anderson ; S. Brzev
- Book Title / Journal: Proceedings of the 15th World Conference on Earthquake Engineering, Lisbon, Portugal
- Year: 2012 , Volume: , Series:
- Earthquake engineering
- Keywords: reinforced masonry ; shear walls ; Seismic resistance
- Description
- This paper presents results of an ongoing two-phase experimental research program on the out-of-plane instability of reinforced masonry (RM) shear walls under seismic loading. Phase 1 involves testing of five reinforced masonry uniaxial specimens under reversed cyclic tension and compression. The specimens represented the end zone of a RM shear wall. The purpose of the testing was to gain insight into the factors influencing out-of-plane instability. The design parameters considered in the study include longitudinal reinforcement ratio and height-to-thickness (h/t) ratio. An analytical model was proposed to estimate the magnitude of critical tensile strain leading to out-of-plane instability. Phase 2 involves experimental and
analytical study of full-scale RM shear wall specimens subjected to reversed-cyclic lateral loading, with the main objective to develop a rational analysis procedure and criteria for assessing the out-of-plane stability of these walls. This paper presents the results of Phase 1 experimental study and explains the Phase 2 experimental
program.
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- 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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- The development of a simplified modeling technique for the finite element analysis of reinforced masonry shear walls
- M.I. Abdellatef
- Book Title / Journal: M.Sc. Thesis
- Year: 2011 , Volume: , Series:
- Structure types ; Masonry Structures
- Keywords: shear walls ; Finite element analysis ; Masonry Structures
- Description
- Reinforced masonry shear walls are structural elements that are commonly used in construction. It is important to properly model their contribution to the strength and stiffness of the structures in which they appear. Analysts typically represent these shear walls with deep beam elements within building models. However, the assumption that a shear wall behaves as a deep beam breaks down when shear failure occurs, and cracking starts to dominate the behavior of the wall. There is a need to develop a finite element model of these shear walls that is accurate but simple enough to be included as a part of a full building model.
A 2-D masonry shear wall model was developed to meet these requirements. To make it
applicable within standard structural analysis software, the model does not require a detailed
representation of each component of the wall separately. Instead, the reinforcing is smeared and
overlaid with a plane stress masonry element. Plasticity is assumed for the steel and
cracking/damage is assumed for the masonry. Reductions in masonry stiffness were applied to
account for initial cracks, and artificial damping was added to stabilize the solution process after the
occurrence of masonry damage.
Data from two experimental test programs were used to verify the proposed modeling technique along with comparisons with detailed finite element models. It was found that the behavior of the simplified models was quite close to that of the detailed finite element models for all cases considered. When compared to the peak values of cyclic load of the experimental specimens, it was found that initial stiffness, peak load, and displacement at final failure were well predicted although, for short shear walls which are dominated by shear failure of the masonry, damage did not evolve as rapidly in the finite element models as was observed in the experimental specimens. The proposed modeling technique was therefore shown to reasonably predict reinforced masonry shear wall behavior, even with coarse meshing and smeared steel reinforcement, regardless of the wall aspect ratio, amount of axial vertical load applied to the wall, and reinforcement ratio.
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