Chan Iathong

Assistant Professor

Structural Engineering

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NUMERICAL MODEL FOR 3D STEEL MOMENT FRAMES
Most previous studies only considered the behavior of steel moment frames under unidirectional
ground motions. Additionally, the numerical models of most previous studies considered the behavior of
only beams and columns, and ignored the behavior of the panel zone of the beam column connection.
Our research proposes a novel numerical model for studying steel moment frames undermulti-directional loadings to consider the 3D elastoplastic behavior of beams and columns, as well aspanels. The proposed numerical model was validated by analyzing cruciform subassemblies of beams,columns, and panels, and the analysis results were compared to the experimental results from previousstudies. The results of the proposed numerical model corresponded well with the respective test results
REQUIRED COLUMN OVERDESIGN FACTOR OF 3D STEEL MOMENT FRAMES
Steel moment frames are designed to ensure sufficient energy absorption capacity by achieving anentire beam-hinging collapse mechanism under severe earthquakes. Therefore, the column overdesign
factor is stipulated in seismic design codes. Since square tube columns are often used for steel structurebuildings in Japan, the two orthogonal planes of the structure are both designed as moment resisting
frames. Considering the effect of bi-direction ground motions on the steel moment frames, the specified
column overdesign factor is 1.5 or more in Japanese seismic design code. However, the required column
overdesign factor of steel moment frames is obtained from analysis results conducted underunidirectional ground motions
Our research describes the results of the earthquake response analysis of 3D steel moment frames, andpresents seismic demand for the column overdesign factor, depending on input direction and amplitudeof the ground motion and width-thickness ratio of columns, required to keep the damage below the limitof plastic deformation of square tube columns.
SEISMIC STRUCTURAL REINFORCEMENT IN DEVELOPING COUNTRIESIn Japan, retrofit method with steel brace frame for RC structure are always used. Retrofitting withsteel braced frame a lot of studs and anchor bolts are required to fix the steel frame and transmit thetensile stress of diagonal brace to the existing RC frame. However, this method needs heavy equipment
and it is difficult to use particularly in rural area, constricted area or remote island.
For seismic retrofitting in the areas mentioned above, we have been developed a new seismic
retrofitting method by using CFST (concrete-filled steel tubular) diagonal brace which act onlycompression, and propose a new hybrid pre-cast member composed of steel tube, cement grout andwood (WGFST) to satisfy the requests from developing area.
23D steel moment frame; square hollow-section column; panel zone of beam column connection;
time-history response analysis; multi-directional ground motion; numerical model; multi-spring model;
Composite members; Seismic retrofit; Brace member; CFST.

3We analyze the behavior of structures through loading experiments and numerical analysis to create
better design methods and seismic resistance methods. We are also planning to develop construction
method with good efficiency.
researchmap https://researchmap.jp/dlucifer64
For the future 100 years from now, I want to work together to create design and construction methodsthat I haven't seen yet.

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