實尺寸鋼結構梁柱彎矩接頭試驗與分析

Abstract

韌性抗彎矩構架之梁柱接頭常藉著補強或減弱方式之改良以提高其塑性變形能力。設計上藉由於梁構件上形成塑鉸，以達遠離梁柱交接面，並藉由此塑鉸達消能之效果。本研究採用有限元素分析與實尺寸梁柱接頭試驗，探討箱型柱梁柱接頭之耐震行為。實尺寸試驗進行四組梁柱接頭試驗，其中兩組試體採用銲接扇形開孔改良型式，另外兩組試體採梁腹板開孔型式。試驗結果顯示經由銲接扇形開孔的改良，可避免扇形開孔根部之撕裂破壞，試體可達4%弧度層間變位角，但仍無法避免梁翼全滲透銲道應力集中造成之破壞。梁腹板開孔之兩組試體經由試驗結果得知，此改良型式可有效於梁腹板開孔區產生塑鉸，並皆可發展出良好的韌性行為與大於梁標稱塑性彎矩之撓曲強度。銲接扇形開孔的改良與梁腹板開孔型式的梁柱接頭可發展良好之耐震行為。

Steel beam-to-column moment connections used in moment-resisting frames can enhance their plastic deformation capability by either reinforcing the connection or weakening the beam section. The connections are designed to form plastic hinge in the beam to be away from the beam-column interface and to dissipate energy through the formation of the plastic hinge. This study aims to investigate the seismic behavior of steel beam to box column connections by conducting finite element analyses and full-scale tests. Four full-scale specimens were tested. Two specimens adopted the improved weld access hole (WAH), while the other two specimens were improved by adopting opening on the steel beam web. Test results showed that the specimens with improved WAH can prevent from brittle fracture at WAH and reached 4% rad story drift angle, but can not avoid fracture at the tip of the beam full penetration weld caused by stress concentration. The other two specimens with beam web opening demonstrated that plastic hinge can effectively formed in the beam web opening zone, and developed good ductile behavior as well as flexural strength greater than the beam nominal plastic moment. Connections with improved WAH and beam web opening can develop satisfactory seismic behavior.