Rou Wen

Designs of Special Concentrically Braced Frame Using AISC 341-05 and AISC 341-10

AbstractSpecial concentrically braced frames (SCBFs) are among the most common steel structures for resisting earthquake loads in high seismic regions. Concentrically braced frames (CBFs) are elastically designed as one vertical truss system to resist lateral loads through axial brace members when they are introduced. The explicit capacity-design approach has been fully incorporated into the newest seismic provisions for structural steel buildings. One new analysis section is added into AISC 341-10 to address the inelastic responses of SCBFs. Two separate structural analyses and one additional analysis are required for SCBFs in AISC 341-10. These analysis requirements significantly increase design efforts in typical design offices, and a comprehensive study to demonstrate how such an explicit inelastic design procedure would (or would not) significantly improve seismic performance of SCBFs appears to be justified. This paper summarizes the seismic design of three SCBFs with different heights, namely, 4, 1...

Seismic Energy Demands in Steel Moment Frames

This study presents an energy approach to the seismic evaluation of steel moment resisting frames. A structure subjected to strong ground motion is supposed that it shows nonlinear behavior. Energy parameters is a way to specify the structural damage. Input energy is depend on the characteristics of the structure and ground motion. Structural design can be defined as the equilibration of the input energy and the energy dissipation capacity of the structure. Structures subjected to eartquake are supposed to dissipate all the input energy. Studies based on energy concepts are usually applied to single-degree-of-freedom (SDOF) system. For multi-degree-of-freedom (MDOF), more researches and new simpler methodologies are still needed in performance based evaluation including energy parameters. In this study , low – medium and high rise steel moment frames and will be studied in linear and nonlinear time history analysis. The results obtained from these analysis are reviewed for seismic energy demands.

Amplified Seismic Loads in Steel Moment Frames

This study focuses on exploring the seismic axial loads for columns in steel moment resisting frames (SMRFs) under strong ground motions. For this purpose, the increases in axial loads are investigated at the maximum lateral load level and the corresponding lateral displacement. The results are presented in terms of maximum amplification factors (Ω0) of all frame columns under the selected ground motions and axial load-moment levels in columns. four typical steel moment resisting frames representing typical low, medium and high rise steel buildings are designed based on the seismic design requirement in ASCE 7-10 and AISC 341-10 . An ensemble of ground motions range from moderate to severe are selected to identify the seismic response of each frames. Two sets of ground motions corresponding to 10% and 2% probability of exceedance are used in nonlinear dynamic time history analyses.