Structural Mechanics Laboratory
Staﬀ
Laboratory URL
Key words

Professor

Shoji NAKAZAWA（E-mail：nakazawa@ace.tut.ac.jp ）http://www.st.ace.tut.ac.jp/~nakazawa/
Shell and spatial structure, steel structure, numerical analysis, vibration control,
buckling, risk analysis

Spatial structures, such as the gyms for elementary and junior high schools, are often used as evacuation
area or disaster prevention bases during a disaster, and so they have to be built to be resistant to seismic
motions. These kinds of structure are easily accessed by the public, and needs to oﬀer suﬃcient safety inregard to earthquakes, wind, and snow. The laboratory performs the following research themes; (1) analysisof seismic response characteristics of spatial structures subjected to severe seismic motion; (2) evaluationof seismic resistance capacity; (3) proposal of design methods with vibration control to reduce the damages;
and recently (4) proposal of super light structures using low volume, recyclable materials and construction
methods, and (5) a grid parallel computing system in order to provide eﬀective analysis.
▲Evaluation of seismic performance of shell and spatial structures
Theme 1
As spatial structures vibrate in a diﬀerent way from high-risebuildings, it is necessary to analyze the response characteristic
and seismic capacity of spatial structures. We therefore performthe following researches; (1) analysis of seismic responses andcollapse characteristics; (2) proposal of the equivalent static seismic
Shaking of a mid-story isolation dome during anload; (3) research of evaluation method of seismic performanceearthquake (When seismic isolation is not used,based on the pushover analysis; (4) research of vibration control
the dome shakes severely, but the use of seismic
methods to reduce the responses for spatial structures ( ﬁg.1).
isolation greatly reduces the response of the dome)▲

Theme 2
Evaluation of buckling strength of shell and spatial structures
Shell and spatial structures can be realized using a lightweight
construction, making their composite materials narrow and thin.
This means that investigations into overall buckling and bucklingfor parts are important. We perform the following researches;(1) development of analysis programs that take buckling andturning into plastic of parts into account; (2) development ofbuckling design methods for spatial structures; (3) performing
collaborative research of a visualization system with otherUniversities.
▲

Theme 3Development of seismic performance evaluation
techniques based on seismic risk analysis
Seismic risk analysis is a stochastic method( ﬁg.2). It is our aim
to use seismic risk analysis to establish a method to quantiﬁably
evaluate the seismic performance of a structure. Our research
themes include; (1) a comparison of detached base isolation
housing and seismic-resistant housing based on seismic risk
analysis; (2) proposal of seismic retroﬁt method based on theminimum standard of lifecycle costs; (3) analysis of the capability
to maintain functioning for school gyms and factories; (4)proposal of evaluation indexes for regional disaster prevention
capabilities.
▲

Development of structural design approach
Theme 4using a grid computer system
Advanced structural analysis of large structures and seismic
risk analysis requires faster computers. In order to realize highspeed operations, we have therefore adopted a parallel gridcomputing system (grid system) as the foundation technology forthe numerical analysis(ﬁg.3), and research into how this would
be used in the ﬁelds of architecture and civil engineering.

Outline of seismic risk analysis (allows forquantiﬁable evaluation of seismic retroﬁtting,base isolation and response control)

Outline of grid computing (A grid system
connects multiple computers across a network,
allowing them to perform parallel computations
and achieving high speed operations. Applied tostructural engineering)