TABLE OF CONTENTS Anchorage was defined previously as the tying together of the major elements of a building with an emphasis on the transfer of lateral (wind and earthquake) forces. A systematic approach to anchorage involves a consideration of load transfer in the three principal directions of the building.
Chapter 10 illustrated the anchorage requirements at the base of a woodframe shearwall. This chapter continues the anchorage problem with a detailed analysis of the connection between the horizontal diaphragm and the shearwalls. Additional considerations for shearwall anchorage and overturning are addressed in Chap. 16. Several typical anchorage details are analyzed including connections to wood-frame shearwalls and concrete or masonry shearwalls.
Following the subject of diaphragm-to-shearwall anchorage, the subdiaphragm concept is introduced. This design technique was developed to ensure the integrity of a horizontal plywood diaphragm that supports seismic forces generated by concrete or masonry walls. Its purpose is to satisfy the Code requirement that continuous ties be provided to distribute these larger seismic forces into the diaphragm. Referenced in Sec. 1620 of the IBC, ASCE 7 Sec. 9.5.2.6.3.2 includes subdiaphragm requirements for Seismic Design Categories C and higher. This is also an anchorage problem, but it is unique to buildings with concrete or masonry walls.
Horizontal diaphragm anchorage refers to the design of connections between the horizontal diaphragm and the vertical elements of the building. These elements may support the horizontal diaphragm, or they may transfer a force to the diaphragm.
A systematic approach to anchorage...
