การเปรียบเทียบค่าโมเมนต์ทุติยภูมิในพื้นไร้คานคอนกรีตอัดแรงที่วิเคราะห์ด้วยวิธีโครงข้อแข็งเสมือนสองมิติและวิธีไฟไนท์อิลิเมนต์แบบแผ่นสามมิติ

Abstract

For post-tensioned concrete, the pre-stressing tendons are positioned so that their curved profiles can resist the loads. For the flat slabs which are indeterminate structures, these profiles will create vertical downward forces near the columns which create the secondary or hyperstatic moments in the slabs. These secondary moments have significant effect and must be considered during the analysis and design processes. Nowadays, many flat slab designers usually use either (1) the Equivalent Frame Method or EFM which consider the structure in 2-dimension (2D) and (2) Plate Finite Element Method which is 3-dimensional (3D). This paper presents the comparison between the secondary moments in post-tensioned flat slabs analyzed from 2D EFM and 3D Plate Finite Element Method using RAM Concept program. Five studying cases with different column layouts have been compared.