Development of Innovative in-Line Stiffening Element for Out-of-Plane Masonry Walls

• Author / Creator

  Entz, Joseph

• Tall, slender masonry walls are a competitive solution for resisting both out-of-plane (OOP) and gravity loads in low and high-rise structures. The use of taller and thinner walls is appealing due to the use of less material, need for smaller foundations, faster construction, lower seismic forces, and the ability to create more interior space. However, the design of OOP loaded tall masonry walls, in accordance with CSA S304, has practical limits related to axial load capacity, buckling stability, and reinforcement details. Most conventional masonry wall designs rely on a single reinforcement layer located at the centre of the unit. Designers who seek to enhance wall strength and stiffness by opting for multiple layers of reinforcement or non-conventional units are hindered by empirical limits in the S304 standard. A new type of masonry slender wall, based on a concept similar to seismic boundary elements, is proposed in this study. These elements act as localized regions of strength and stiffness by providing tied reinforcement in two layers close to the surface of the wall. Results of experimental tests on five course high masonry prisms, containing pre-tied steel reinforcement cages and specially designed masonry units to fit around the cages, indicate that the innovative reinforcing cage has a beneficial effect on both the flexural strength and stiffness of masonry prisms. The response of four 12 course high masonry walls tested under combined axial and OOP load, is also presented. The results indicate that walls with two layers of reinforcement have greater OOP stiffness and flexural strength in comparison to conventionally reinforced walls.A mechanics-based fibre-section model utilizing plane-section compatibility is used to compare the performance of cage reinforced prisms and walls to conventionally reinforced prisms and walls with various amounts of conventional reinforcing steel.

• Subjects / Keywords

  • Stiffening Element
  • Reinforced Masonry Wall
  • Masonry Prisms
  • Out-of-Plane Masonry Wall

• Graduation date

  Spring 2019

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-hqmd-9b94

• License

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