Finite Element Assessment of Methods for Incorporating Axial Load Effects into Blast Design SDOF Analyses of Precast Wall Panels

Abstract

Innovations in the U.S. construction and precast concrete manufacturing industries have resulted in efficient methods of constructing multistory buildings that are entirely supported by precast concrete walls (i.e., no structural frame). Simultaneously, the U.S. government has mandated overarching requirements and incentives that promote energy efficiency in all government buildings and facilities. The combination of construction efficiencies and relatively recent requirements for improving energy efficiency makes total precast construction an attractive option for constructing government, diplomatic and U.S. Department of Defense (DoD) buildings and facilities. However, to design load bearing wall panels for DoD blast response criteria, engineers need a relatively simple method for analyzing dynamic response under combined lateral and axial load effects. This paper presents methods for incorporating the P-delta and P-M interaction effects into the single-degree-of-freedom (SDOF) framework that is widely used for blast analysis and design, and evaluates the developed methods using high-fidelity nonlinear static and explicit nonlinear dynamic finite element models of load-bearing precast panels. The work demonstrates that currently used methods that do not properly consider the effects of axial loads on resistance may be grossly over conservative, and demonstrates that the easily-implemented methods developed through this research provide accurate results.