Events

Distinguished Lecturer

PERFORMANCE-BASED DESIGN OF RC CORE WALL
BUILDINGS LOOKING BACK & THINKING AHEAD

Presented by:


Dr. John Wallace
 

Professor of civil engineering at the University of

California, Los Angeles (UCLA)

Abstract:

Reinforced concrete (RC) core walls, consisting of wall segments and coupling beams, are widely used as a lateral-force-resisting systems in taller buildings to resist wind and earthquake forces. Despite extensive use of nonlinear analysis over the last 30 years to verify expected performance of tall buildings subjected to earthquake shaking using alternative design approaches (i.e., Performance-Based Seismic Design), current analysis and design approaches still involve the use of relatively crude approaches. For example, modeling of coupling beams, which are the primary energy dissipation elements of a coupled core wall, is typically based on use of simple beam element models with a single shear hinge at midspan and rigid axial behavior (i.e., a rigid in-plane diaphragm assumption). Modeling vertical wall segments of the core wall typically involves use of single layer elements with simplified force-deformation behavior (i.e., use of multi-linear uniaxial material models, plane-section assumption, uncoupled P-M and V behavior). Based on the use of these models, and other factors, predicted demand levels may include considerable uncertainties. In addition, engineering demand parameters are commonly based on average values determined from a suite of ground motions versus assessing demands from each ground motion pair individually. Finally, models used for element capacities are commonly the same as those used for prescriptive code-based design that generally include inherent conservatism that are not necessarily appropriate for more comprehensive design approaches based on use of nonlinear response history analysis. Recent research conducted at UCLA has focused on addressing these issues by developing improved modeling approaches, validating these modeling approaches by comparing model and test results, and creating new models for element capacities for critical actions. Research results will be summarized to identify possible future directions for tall building design based on use of nonlinear analysis approaches.

About the Speaker:




Professor Wallace’s research contributions focus on assessing the behavior of structures subjected to earthquake loading, conducting laboratory and field testing of structural components and systems, developing and validating models for structural analysis and design, and applying sensors and sensor networks to measure structural responses and interactions. He has actively participated in updates to ASCE 41, ACI 369, and ACI 318 and is Chair of ACI Committee 318H – Seismic Provisions. He is a member and past-President of the Los Angeles Tall Buildings Structural Design Council. Dr. Wallace received a BS in Civil Engineering from the University of Vermont and MS and PhD in Civil Engineering from the University of California, Berkeley.

Date: Thursday, November 14
Time: 12:30 PM - 1:30 PM
Location: ECJ 3.116

Pinthouse pizza will be provided.

Contact: This email address is being protected from spambots. You need JavaScript enabled to view it.; Assistant Professor