5.1 Composite wall anchors

Composite materials can be used to upgrade the load-carrying capacities of unreinforced masonry walls. The strength of the upgraded wall, however, is often limited by failure that occurs near the bottom of a wall due to a low capacity for load transfer between the wall and the foundation. The present paper provides information on an experimental investigation of a composite anchoring system on unreinforced concrete masonry walls. This system provides high-capacity load transfer between the fibre reinforced polymer (FRP) laminate retrofitted wall and the foundation.

Six masonry wall-concrete footing assemblages were built, strengthened with FRP laminates, and tested. On all walls, a composite anchoring system provided the only connection between concrete foundation and masonry wall. Three walls (1219 mm × 1219 mm) had composite laminate applied in edge strips to both faces and were subjected to in-plane shear and a 22.24 kN axial load. The capacity of these walls reached more than 120 kN (lateral load) before failure, which resulted from extensive cracking of the masonry units. The other three walls (406 mm × 1016 mm) had the tension surface fully covered with CFRP laminate and were tested in tension (bending) reaching a maximum load of 32 kN before failing due to masonry unit crushing. In each loading case, the anchoring system provided sufficient strength allowing the masonry units to fail before the CFRP laminate or composite anchors failed.

The results of this research reveal that strength gains due to FRP laminate upgrades on unreinforced concrete masonry walls can be fully realized through the use of a composite anchoring system.

• INTRODUCTION AND OBJECTIVES

• SPECIMEN AND TEST DETAILS

• STRENGTHENING DETAILS AND TEST RESULTS

• CONCLUSIONS

• ACKNOWLEDGEMENTS

• REFERENCES