林聪悟-直线法在基于美国混凝土规范设计中的程序实现

首先,阐述了美国ACI318-08规范中钢筋混凝土受弯、受压构件的设计原理和基本假定。与我国混凝土结构设计规范不同,ACI318-08规范是根据构件的受力破坏形态来确定名义抗压和抗弯承载力的折减系数的,相对于延性破坏,脆性破坏构件的承载力折减较多。然后,由平衡条件、平截面假定及Newton迭代格式,推导出林聪悟-直线法的计算公式。编制程序实现该算法时,须根据最大、最小配筋率的规定对迭代区域进行限定;在确定P-M相关曲线上的拐点位置的基础上,实现中性轴高度在曲线上的分段迭代。通过在曲线拐点处设置微小增量及自动调整中性轴高度等方法,解决了程序计算时可能出现的迭代发散问题。算例表明,所编制程序的计算结果具有很高的精度。

Seismic Evaluation of Reinforced Concrete Frames in the Harsh Environment Using Pushover Analysis

The main objective of this paper is to evaluate the seismic response of buildings of typical reinforced concrete frames when concrete starts to deteriorate gradually and to make a comparison between the base shear and the displacement at different stages of earthquake loading. Typical 5, 15, 20 and 30-storey reinforced concrete frames have been designed for seismicity according to the recently adopted seismic code in Abu Dhabi, ACI 318-08/IBC 2009 code. A pushover analysis has been performed to these four buildings by using SAP 2000. Twenty-four models have been created (6 models for each building) by decreasing the concrete strength gradually from 4000 psi (281 kg/cm2) to 1500 psi (105 kg/cm2). This is to simulate the effect of harsh environment on the strength of concrete in existing buildings.

中美钢筋混凝土梁的受弯性能对比研究

基于中、美单筋混凝土梁的截面试验结果,对中国《混凝土结构设计规范》(GB50010-2010)、美国规范(ACI318-08)的钢筋混凝土梁正截面设计方法进行对比分析。结果表明,在适筋范围内,美国规范的最小配筋率比我国规范要高;此外在设计方法、受弯承载力等方面都有所不同。