Performance of Flexure-Controlled Reinforced Concrete Structural Walls Under Sequential Fire-Earthquake Loads
Abstract
The performance of reinforced concrete (RC) structural walls under individual hazards has been well studied. However, little is known regarding the behavior of RC structural walls under sequential hazards. The research presented here seeks to address the performance of RC structural walls under sequential fire-earthquake loads (both post-earthquake fire and post-fire earthquake).
Longer burn times of post-earthquake fire and initial seismic damage can have significant structural impacts on RC structures which are usually considered to have superior performance in a fire. An 8-inch wall with characteristics representative of typical construction in seismic regions was utilized as the basis of the simulations. The wall with non-uniform layout of reinforcement provides a complex deformed shape under fire. Individual typical earthquake damage states were introduced to the wall to assess impact on fire resistance. The fire resistance of a wall was discussed according to thermal-insulation and load-bearing criteria in codes. The results show that crack does not impact the fundamental response of a wall under fire while cover loss decreases its load-bearing capacity significantly. Moreover, the location of cover loss has remarkable impact on the deformed shape of a wall and its load-bearing fire resistance. While the thermal-insulation capacity decreases below code requirements, the load-bearing fire resistance of earthquake-damaged walls is still acceptable.
Another potential but infrequently studied hazard is the post-fire earthquake scenario. The impact of fire damage on the earthquake behavior of RC walls is not well understood, which leads to some safety concerns in earthquake after fire or aftershocks after post-earthquake fire. A simulation procedure combining SAFIR and OpenSees is proposed and validated for the PFE analysis of RC structural walls. Based on the validated the simulation procedure, a parametric study on the PFE performance of RC walls was conducted. Results indicate that fire damage decreases the load-bearing capacity and stiffness of RC walls under reversed-cyclic loads while fire damage decreases the deformation capacity in most cases. Severe fire exposure may shift damage from the boundary element to the web. Wall characteristics which significantly impact the residual wall response quantities are wall thickness, boundary element length, and axial load ratio. In addition, a framework for simplified nonlinear modeling was proposed for the PFE performance of RC walls. The models are defined by modification factors that account for the change in wall response relative to that of a wall without fire damage. Modification factors, established from the results of the parametric study, are a function of fire damage indices that account for the effect of fire on the material properties of steel and concrete. Results indicate that the model is generally able to predict the response of a fire-damaged wall.
Subject
flexure-controlled reinforced concrete structural wallssequential fire-earthquake loads
post-earthquake fire
post-fire earthquake
earthquake damage
thermal-insulation fire resistance
load-bearing fire resistance
stiffness
strength
drift capacity
failure curvature
damage ratio
fire damage indices
Citation
Ni, Shuna (2018). Performance of Flexure-Controlled Reinforced Concrete Structural Walls Under Sequential Fire-Earthquake Loads. Doctoral dissertation, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /173912.
Related items
Showing items related by title, author, creator and subject.
-
Wu, Jie Ying (Texas A&M University, 2004-09-30)Though the idea of pre-impact recovery preparedness planning has recently been promoted by federal and state governments, very little research has been done to evaluate how it affects the process of disaster recovery. This ...
-
Dynamic Modeling of Earthquake Cycles on Complex Faults, Scenario Earthquakes, and Off-Fault Damage Liu, Dunyu (2018-11-12)The dissertation is devoted to developments of numerical methodologies to simulate physical processes of various earthquake phenomena and their applications. In the first study, we develop a dynamic earthquake simulator ...
-
Jiao, Leiyin (2019-11-15)Dynamic ruptures of the 2016 Meinong earthquake and potential ground motion induced by earthquake scenarios on the geometrically complex Chinshan-Shanqiao faults in Taiwan have been modeled. Realistic 3D velocity structures ...