ABSTRACT
After reading this chapter, you will be able to:
Compute seismic load combinations
Determine the redundancy factor
Explain the overstrength factor
Perform calculations used to determine earthquake loads using the equivalent lateral force procedure (ELFP)
Perform calculations used to determine earthquake loads using modal response spectrum (MRS) analysis
Describe seismic response history procedures
Design of structures must be based on a minimum standard of care to safeguard the safety, health, and welfare of the public. Municipal, state, or federal governments concerned with the safety of the public have established building codes used to control the construction of structures within their jurisdiction. These design codes specify among other things the design loads. While building codes may vary from city to city, most municipalities rely on regional codes and design standards for the specification of loads. These codes and standards include general building codes, such as the International Building Code (IBC) and the ASCE/SEI (2010) “Minimum Design Loads for Buildings and Other Structures” standard, from here on referred to as ASCE-7. These codes and standards are developed by various organizations and present the best opinion of those organizations as to what constitutes good practice. In this chapter, we provide an overview of structural design philosophies and explain how seismic loads are incorporated as part of structural design. The primary focus of this chapter is to describe the parameters associated with determining earthquake loads in accordance with ASCE-7 and to demonstrate the procedures for determining earthquake loads using the ELFP, seismic response history analysis, and MRS analysis.