The numerical model proposed for simulation of out-of-plane instability in rectangular walls is further examined in this paper by predicting the in-plane and out-of-plane responses of a singly reinforced wall specimen that was tested in Switzerland (EPFL). The model predictions were compared with the experimental measurements and the capability of the model to capture this mode of failure was verified by the researchers at EPFL.
This paper elaborates on the experimental results of three rectangular wall specimens that were designed according to the New Zealand concrete design standard and were tested under in-plane cyclic loading. The possible failure modes of the New Zealand modern ductile walls and the adequacy of the wall design provisions are discussed in light of the experimental observations.
This paper describes a modeling approach that can be used to predict the out-of-plane instability of rectangular walls under in-plane cyclic loading and presents the in-plane and out-of-plane response simulation for several singly-reinforced and doubly-reinforced wall specimens tested in the literature.
This paper discusses the sequence of events that result in formation of out-of-plane deformation and subsequent instability in rectangular walls under in-plane loading. The experimental observations of a wall specimen that failed in pure out-of-plane instability are used for this purpose. The wall was designed according to the New Zealand concrete design standard and the potential changes to the wall design section of this standard to prevent this mode of failure are discussed in detail in light of the experimental observations and analytical predictions.
This paper describes the strengths and limitations of a modeling approach that can be used for numerical simulation of different failure modes of reinforced concrete structural walls. Experimental results of several wall specimens that exhibited various failure modes are used for parametric evaluation of the modeling approach.
Principal Investigator: Des Bull
After the Canterbury Earthquakes the Royal Commission and SESOC raised issues relating to the design of lightly reinforced and precast concrete walls. This research project looked to address and give guidance on the following:
• Determine minimum reinforcement requirements and deformation capacity of for lightly reinforced walls.
• Determine the deformation capacity of older singly reinforced walls.
• Evaluate the capacity of precast walls with grouted connections and identify improved connection details.
• Evaluate out-of-plane deformation capacity of base connections for singly reinforced walls, including bi-directional loading.
A series of 47 wall experimental tests and extensive numerical modelling was undertaken to verify the behaviour of existing wall designs, as well as to investigate improved design procedures and details. A further 38 tests conducted prior to the commencement of this research project were analysed to maximize the data set available.
The research has led the the publication of numerous journal papers and direct contributions to New Zealand and overseas standards. Major outcomes are listed as:
• Adoption of proposed minimum vertical reinforcement requirements in NZS 3101:2006 (A3) – published July 2017.
• Acceptance of proposed minimum vertical reinforcement requirements by ACI 318.
• Recommendations made to C5 review committee of the MBIE seismic assessment guidelines.
• Guidance drafted on connection detailing of low-rise precast panels and initiation of joint ConcreteNZ and SESOC guidance document.
Work on this topic is ongoing, with further work being undertaken which aims to provide additional guidance to practicing engineers.
Author: Richard Malcolm
Supervisors: Professor Jason Ingham and Adjunct Professor Des Bull.