Civil Engineering Association

An alternative procedure for seismic analysis & design of tall buildings located in the LA region

Code provisions are intended to provide a minimum level of safety for engineered buildings. The code prescriptive provisions are intended to provide safe design criteria for all types of buildings, ranging from small one and two story dwellings to the tallest structures. As a result of this broad intended applicability, the provisions contain many requirements that are not specifically applicable to tall buildings and which may result in designs that are less than optimal, both from a cost and safety perspective. Advances in performance based design methodologies and maturity of capacity design principles now permit a more direct, nonprescriptive, and rational approach to analysis and design of tall buildings. This document relies on these advances to provide a rational approach to seismic design of reliable and effective tall building structures. This Document addresses only non-prescriptive seismic design of tall buildings.

This document is not intended to cover essential facilities.

This provisions of this document are justified based on Section 104.11 of 2006 edition of International Building Code (2006 IBC) and Section 108.7 of 2007 California Building Code. These code provisions permit application of alternative lateral-force procedures using rational analysis based on well-established but complex principles of mechanics in lieu of prescriptive code provisions. All codes have traditionally permitted the use of alternative analysis and design methods which can be justified based on well-established principles of mechanics and/or supported by convincing laboratory test results. For example, Section 12.6 of ASCE 7-05 which is adopted by reference in 2007 CBC states:
"The structural analysis required by Chapter 12 shall consist of one of the types permitted in Table 12.6.1, based on the structure's seismic design category, structural system, dynamic properties, and regularity, or with the approval of the authority having jurisdiction, an alternative generally accepted procedure is permitted to be used. ..."




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LATBSDC 2014,An Alternative Procedure For Seismic Analysis And Design Of Tall Buildings Located In The Los Angeles Region

Los Angeles Tall Buildings Structural Design Council (LATBSDC)
LATBSDC 2014 Conference
An Alternative Procedure For Seismic Analysis And Design Of Tall Buildings Located In The Los Angeles Region

The intent of the document is to provide a performance-based approach for seismic design and analysis of tall buildings with predictable and safe performance when subjected to earthquake ground motions. These provisions result in more accurate identification of relevant demands on tall buildings. As such, the application of the procedure contained in this document is expected to result in buildings that effectively and reliably resist earthquake forces.

Seismic design of buildings in accordance with these guidelines can offer a number of advantages including:
• More reliable attainment of intended seismic performance.
• Reduced construction cost.
• Elimination of some code prescriptive design requirements.
• Accommodation of architectural features that may not otherwise be attainable.
• Use of innovative structural systems and materials.

Notwithstanding these potential advantages, engineers contemplating a building design using this document shall give due consideration to the fact that appropriate implementation of these recommendations requires an in-depth understanding of ground shaking hazards, structural materials behavior and nonlinear dynamic structural response.