CUREE Banner

Projects : CUREE-Kajima Joint Research Program

Overview
Now in our second decade of Kajima-funded projects, the CUREE-Kajima Research Program is a joint venture with the Kajima Corporation of Japan involving collaborative studies among researchers in the US and Japan. The topies researched have spanned many areas, but the theme of inter-university collaboration, and in this case international collaboration, remains the same.

PHASE VI -
INVESTIGATION OF FACTORS LEADING TO PROGRESSIVE COLLAPSE OF STRUCTURES

Category I: Evaluation and Development of Analytical Tools

Research Team: Sivaselvan Mettupalayam (University of Colorado at Boulder);
Andrei Reinhorn and Gary Dargush (Univerity at Buffalo-SUNY)

Background
The result of several years of developing models for collapse of elements and structures has resulted in numerous publications listed in the references below. Two specific areas were developed: (1) hysteretic models with sudden or gradual deterioration contributing to loss of strength and stability and (2) modeling collapse of single elements and simple structures due to strength deterioration, stability and load redistribution. Several commercially available computer programs developed to date are capable of analyzing and simulating collapse based on applying static and ad-hoc dynamic approaches and based on simple idealized mechanisms resulting from sudden loss of strength. However, these approaches do not reflect entirely the true dynamic nature of the gradual progressive collapse observed in structural collapse and laboratory experiments. Moreover, such computer programs are usually based on very fine-grained approaches such as highly refined finite element models which are computationally cost-prohibitive in analyzing complex built structures.

It is therefore proposed to perform a study to identify the gaps in the existing computational methods and their software implementations using several case studies. This will help identify the most appropriate framework for further integration of new models and important parameters influencing progressive collapse. The proposed study will have four tasks:

TASK LIST
1 - Review existing computational models and numerical algorithms
2 - Evaluate the performance of selected models and algorithms
3 - Identify preferred algorithms and limitations by analyzing case study building(s)
4 - Develop improved models and algorithms as needed

Category II: Analysis of Structural Component Failure

Researcher: Stephen Mahin (University of California, Berkeley)

Background
The work within this project will complement activities to be undertaken by other CUREE investigators and Kajima researchers. Activities within the overall project include work related to analytical methods and models necessary to predict and simulate the collapse of complete structural systems (Category I investigations at the University of Buffalo by Andrei Reinhorn), and more focused studies to develop, validate and exercise member and material models for the prediction of the initiation and propagation of failures in components within a complete structure (Category II investigations). As part of the Category II investigations, various computational platforms, component models, failure modes and damage representations will be investigated, and data from past experimental research needed to develop or validate these predictions will be collected. Primary focus will be placed on simulating failure initiation and collapse of steel moment resisting and braced frames (represented by a 4-5 story case study building to be developed in the project), but time permitting other materials like reinforced concrete will be considered.

Research Plan
The work to be carried out will complement other Category II efforts to be undertaken by Helmut Krawinkler at Stanford University. Whereas the Stanford work will focus on phenomenological models that mimic the behavior of beams, connections and columns (and are calibrated to simulate hysteretic behavior including collapse), the Berkeley team will focus on physical theory and finite element models which require more computational effort, but incorporate more realistic physical representations of members and materials, including the initiation and evolution of damage through complete failure. The Stanford team will focus on beams (including composite behavior with slabs), beam-to-column connections, and columns in moment resisting frames, while the work at Berkeley will tend to focus more on elements, like bracing elements, columns and connections in braced frames that have failure modes that may be influenced by the consequences of lateral and local instability.

The work will be divided into six interrelated tasks. In addition, it is anticipated that over the 24 months of the project that brief progress reports will be provided to project participants every two months (or at other intervals, as directed by the Joint Oversight Committee), face-to-face meetings with other investigators will be held every 6 months (with two of these meetings to be held in Japan and two held on the west coast of the US), and an interim and final report will be provided after 12 and 24 months, respectively.

TASK LIST
1 - Coordination
2 - Classification of Members & Behavior Modes - Catalog Available Relevant Test Data
3 - Identify preferred algorithms and limitations by analyzing case study building(s)
4 - Develop improved models and algorithms as needed


Category II: Analysis of Structural Component Failure

Researcher: Helmut Krawinkler (Stanford University)

TASK LIST
1 - Quantification of modeling paraters for deteriorating components
2 - Study on the effects of deterioration on response of a steel frame structure till collapse


CUREE-Kajima Project

CUREE-Kajima: Phase 6
Project Overview
Project Team Rosters

Prior Research
CUREE-Kajima: Phase 5
CUREE-Kajima: Phase 4
CUREE-Kajima: Phase 3
CUREe-Kajima: Phase 2
CUREe-Kajima: Phase 1
Funded by:
Kajima Corp. Logo


© 2000-2008 CUREE. All rights reserved.
Consortium of Universities for Research in Earthquake Engineering
last updated 02.01.06