| Though the design methods for slab-column structures under vertical loads have developed well, the design methods for slab-column structures under lateral loads still need to be improved. Equivalent frame method (EFM) and effective beam width method (EBWM) are the main two design methods for slab-column systems under lateral loads. Since the calculation of effective column in the EFM is complicated, the EFM cannot be applied in popular structural design and analysis software directly. Different with EFM, EBWM use the cross-section of column and storey height directly, which enables designing slab-column system with EBWM in most structural softwares.Many researches have been done for EBWM by researchers both domestic and abroad, and this method has been proved to be an appropriate design method. But consistency hasn't been gotten for the following issues of EBWM.①The value of elastic effective beam width factor;②The effective beam width for slab column connection on the nonlinear stage;③The nonlinear analysis models for slab-column connections;Focus on these problems, following works have been done:①Introduce design criteria for slab-column structures, and use ABAQUS to establish slab-column models to calculate the moment distribution on slab under vertical loads, then compare Direct Design Method in ACI318 code with Empirical Coefficient Method in Chinese code GBJ 130-90;②417 slab-column connection models with different dimensions have been established in ABAQUS to calculate the effective beam width factors, then the effects of dimension coefficients on the effective beam width factors are analyzed, and finally establish equations between effective beam width factors and dimension coefficients;③ABAQUS finite element method is used to do push-over simulation for 11 interior slab-column connections which were collected from tests in reference documents and 9 self established interior slab-column connections, the influences of reinforcements arrangement and cross-section dimension of column on flexure performance are discussed. Finally, the nonlinear effective width coefficient for the slab-column under lateral load is discussed;④Brief introduce performance based design for slab-column system, the proposed analyze models and control criteria in ASCE41/SEI 41-06 and PEER/ATC-72-1. From the works above, main conclusions as following are gotten:①For slab-column systems under vertical uniformly distributed loads, both moment allocation ratios of Empirical Coefficient Method and Direct Design Method are consistent with the calculation results for inner span, and direct design method is closer to the calculation results for edge span;②Elastic effective beam width coefficientαunder lateral loads is proposed as following: a=3.3c1/l2+0.16×l1/l2+0.11×c2/c1(for slab column connections of inner frame) a=-0.1+2.69×c1/l2+0.06×l1/l2+0.13×c2/c1(for slab column connections of edge frame)③Reinforcement arrangement and dimensions of column and slab are the main factors influence the nonlinear flexure performance of slab-column connections under lateral loads. It is observed to arrange the steels concentrate on the band width c2 + 3h or on the column strip not only can improve the flexure performance but also the steel ability can be fully developed; For the slab-column connections with rectangular column, the flexure performance can be enhanced when the long side of the column is parallel to the lateral load direction; If possible, for the flexure performance of slab-column connections, thicker is better;④It is appropriate to use the equation Y. H. Luo suggested to evaluate the nonlinear effective width reduction factorβif M a / M cr≤2.0; For the interior slab-column connections in nonlinear stage under lateral loads, theβis proposed as following:β=0.4+0.32[{Ma/Mcr-0.7)}-0.5-{(Ma/Mcr-0.7)}0.5]...
|
PDF Full Text Request