Design Optimization and Structural Performance of 3D-Printed Clay Bricks for Load-Bearing Masonry Walls

Abstract

The geometric configuration of masonry units plays a critical role in the structural performance of load-bearing walls. Nevertheless, inefficient brick geometries remain prevalent in self-built construction with limited technical supervision, a condition frequently observed in urban areas of Peru, such as East Lima, contributing to increased seismic vulnerability. This study introduces a topology-optimization-based design framework for clay masonry units compatible with extrusion-based 3D printing and compliant with the Peruvian masonry standard NTP E.070.A traditional brick geometry was adopted as the reference model for parametric development, followed by iterative topology optimization aimed at improving material distribution, reducing mass, and controlling void ratios while ensuring geometric stability during extrusion-based 3D printing. Printability was evaluated through finite element simulations under fresh-state conditions. Among the optimized configurations, only the quadrangular geometry (F-QB) satisfied stability requirements, exhibiting controlled deformation (2.79 mm), whereas an alternative configuration (F-TB) showed excessive displacement (38.87 mm) and was discarded due to insufficient stiffness. At the structural scale, masonry walls constructed with F-QB units were assessed under combined vertical loading (45 tons) and design seismic base shear (1.856 tons). The optimized wall exhibited a maximum displacement of 0.500 mm, representing a 4.4% reduction compared with the traditional wall (0.523 mm), along with a more uniform stress distribution and improved deformation control. These findings demonstrate that integrating topology optimization and 3D printing within a unified digital workflow enables the development of structurally efficient and mechanically stable masonry bricks, offering a viable strategy to enhance structural safety in seismic-prone regions.