Behaviour of Masonry Arches Under Foundation Movement

Naggasa, Ahmed

Abstract

A significant number of UK bridges are masonry arches, with over 60% being more than a
century old and bearing loads beyond their initial design intent. This poses a challenge for longterm assessment. Current assessment tools range from simplistic to complex finite element
analysis models. However, only advanced models capture the brittle nature of masonry and the
structural behaviour of multi-ring arches. Despite extensive research on masonry arches, further
knowledge concerning the effects of foundation movements are required. This study focuses
on the masonry arch subject to foundation settlement, sliding, and rotational movements.
State-of-the-art finite element analysis of masonry arches involves 3D micro-modelling,
utilising the unique material properties of masonry. The bond strength between mortar and brick
is crucial since it governs failure modes. This research used a detailed micro-modelling
approach, using the extended finite element method in ABAQUS, simulating masonry cracking
failures and capturing the non-linear three-dimensional behaviour.
Validation of the numerical models was achieved by comparing output to physical tests
conducted at The University of Salford. Experimental studies on mortar, bricks, and masonry
triplets provided both material properties and further understanding. A distinctive feature was
the modelling of full-thickness mortar, using a cohesive segment approach, enabling damage
simulation in the mortar without pre-set crack locations.
For multi-ring masonry arches with full-thickness mortar joints, cohesive interactions captured
non-linear failures. ABAQUS's normal mesh density proved optimal in load-displacement
representation. Sensitivity analyses were conducted on various factors like non-linear interface
values, Young's modulus of elasticity, and mortar plasticity criteria.
Results revealed accurate predictions of masonry arch failure mechanisms. The validated
models were subjected to foundation settlement, sliding, and rotation tests, revealing changes
in structural behaviour due to foundation movement. Sliding and rotational movements notably
reduced peak load capacity and stiffness due to the widening of existing cracks. Although
settlement movements had minimal impact on peak load capacity, they did reduce stiffness.
Combined movements indicated a pattern in abutment reactions, with the most substantial effect
observed when sliding was double the settlement.

Citation

Naggasa, A. (2024). Behaviour of Masonry Arches Under Foundation Movement. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: May 17, 2024
• Publicly Available Date: Jun 1, 2026
• Award Date: May 31, 2024