Numerical Investigation of In-Plane Behaviour and Strength Prediction of Ungrouted Reinforced Masonry Walls
Bibliographic record
Abstract
This thesis investigates the structural behaviour and design implications of ungrouted reinforced masonry (UGRM) walls as a potentially supplementary alternative to conventional ones, such as fully grouted reinforced masonry (FGRM) or partially grouted reinforced masonry (PGRM) construction, in which grouting is essential in masonry block cells with vertical steel bars, and unreinforced masonry (URM) walls. While FGRM and PGRM walls achieve enhanced strength and stability through grout-bonded vertical reinforcement, they entail increased construction costs, labour intensity, and curing time due to the grouting. However, in UGRM walls, grouting is eliminated, but vertical steel bars remain, being anchored at the top and bottom of a wall without bonding in between. This absence of grout introduces a fundamental challenge: the lack of bond between steel and masonry potentially alters the load transfer mechanism, particularly under lateral in-plane loading. The motivation for exploring UGRM systems stems from the need for cost-effective, rapid-construction solutions. However, the lack of grout introduces uncertainties in the wall’s structural behaviour and design performance, which are not well addressed in existing studies and thus in masonry design standards/codes. Therefore, the central research question addressed in this study is: Can UGRM walls provide reliable in-plane strength and deformation capacity, and how can their strength be reliably predicted using analytical equations similar to those in the existing Canadian masonry standards for FGRM or PGRM walls? To address this research problem, this study is structured in two phases. The first phase of the thesis research focuses on investigating the in-plane behaviour of masonry walls with varying grouting and reinforcement bonding conditions. A total of 50 RM walls, encompassing a range of aspect ratios, were modelled using a simplified micro-modelling approach in ABAQUS. The results indicate that UGRM walls with unbonded reinforcement can achieve sufficient in-plane load carrying capacity and ductility, particularly in low-aspect-ratio configurations, thereby offering a viable and relatively economical alternative for non-slender masonry structures. The second phase of the research critically evaluates the load-carrying capacity of UGRM walls and suggests modifications in the load resistance equations for grouted RM walls in the CSA S304 to develop models applicable to UGRM walls based on extensive numerical simulation data (i.e., for 552 walls). Key parameters, including aspect ratio, axial load level, masonry compressive strength, and reinforcement ratio, were systematically varied. Findings reveal that the CSA S304 provisions, which are derived from fully grouted walls, significantly overestimate the shear and flexural strength of UGRM walls by up to two to three times in certain cases. Note CSA S304 provisions tend to underestimate the shear and flexural strengths of FGRM and PGRM walls as found in the literature. In this thesis, regression analyses were conducted to quantify the influence of each parameter and to develop modified empirical expressions tailored for UGRM walls. The proposed design model demonstrates strong agreement with the numerical results. However, it is important to note here that the numerical simulation data are treated as ground truth due to a lack of sufficient experimental tests, which should be conducted to fully address the critical gap before adopting the proposed models in design standards. Collectively, this preliminary work contributes to the understanding of UGRM wall behaviour and provides a basis for future code development aimed at improving both the safety and economy of masonry construction.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".