There are connections between the floor diaphragm(s) and the walls, capable of transferring in-plane forces from roof to wall and restraining outward displacements of walls.

FWCP_WHE stonemasonry 4-13

Examples of retrofit methods to improve strength of existing wall-to-floor connections in stone masonry buildings with wooden floors (Improving the Seismic Performance of Stone Masonry Buildings, Bothara and Brzev, EERI, 2011)

FWCP_WHE stonemasonry 4-15

Examples of retrofit methods to improve strength of wall-to-floor connections in stone masonry buildings with reinforced concrete floors (Improving the Seismic Performance of Stone Masonry Buildings, Bothara and Brzev, EERI, 2011)

FWCP_-_FEMA_1

Example of retrofit method to improve strength of wall-to-floor connections of a wood diaphragm - note: N refers to New and E refers to Existing components (FEMA 172, 1992)

FWCP_-_FEMA_2

Example of retrofit method to improve strength of wall-to-floor connections of a composite concrete slab and steel deck diaphragm to a concrete or masonry wall; note: N refers to New and E refers to Existing components (FEMA 172, 1992)

FWCP_Canada_Brzev_1

FWCP_Canada_Brzev_2

A retrofitted unreinforced brick masonry building with floor-wall anchors visible at the exterior, Vancouver, Canada (S. Brzev)

FWCP_Seattle_USA_Brzev_1

A retrofitted unreinforced brick masonry building showing exposed floor-wall and roof-wall anchors at the exterior, Seattle, USA (S. Brzev)

FWCP_Seattle_USA_Brzev_2

A typical wall anchor, consisting of a steel rod and an exterior steel plate exposed at the exterior; note that anchor plates are of different shapes and sizes (S. Brzev)