| 摘要: | 本研究繼郭育廷[43]之研究，整理近年來國內外關於鋼筋混凝土梁柱接頭塑性鉸外移試驗成果[6-22]，歸納塑性鉸外移設計形式相關建議以及要點，並以紐西蘭規範NZS3101-2006規定為基礎，提出完整塑性鉸外移設計程序。另外，透過上述蒐集之一般梁試體試驗成果以統計方法檢測高剪應力破壞模式檢核公式的保守性，並建立相關資料庫提供參考。同時利用ETABS、REVIT等商用程式進行實務設計流程之模擬，以探討現場施作塑鉸外移及斜向鋼筋所可能遇到之問題並提出應對方案。
藉由統整國內外試驗有發生剪力滑移行為試體表現，提出剪力滑移破壞特徵，屬於脆性破壞模式，並且常發生在試體於最大載重產生後，試體剪力強度急速下降，並且以統計結果說明，當剪應力過大時可藉加設斜筋來控制試體垂直滑移行為。
模擬案例研究中，利用紐西蘭NZS3101規定剪力滑移設計以及美國ACI318規定剪力摩擦設計模式共配置三種不同形式塑鉸外移改良梁，並藉由BIM方法進行鋼筋配置3D視覺化，在案例一配置額外D29彎起筋當中，彎起強化箍筋與傳統剪力設計橫向箍筋間距過小，在現場有難以澆置之疑慮，相較案例二配置D29斜向直筋橫向箍筋間距較大，對於現地施工較為容易，建議多以案例二之斜向鋼筋複合彎起鋼筋形式進行塑鉸外移設計，有較好的施工性並能有效控制滑移破壞產生。利用ACI剪力摩擦概念檢核發現，案例三以縱向鋼筋插筋作用能符合剪力摩擦需求，且在三種案例中額外鋼筋使用量最少，施工性最佳，惟此案例無配置斜向筋有滑移破壞風險。為此，對於高剪應力作用使滑移風險較高的長跨梁而言，建議採斜向鋼筋配置進行，若其風險較低則建議取剪力摩擦插筋形式進行。
;This study is a simple simulation for designing practical reinforced concrete beam-column joints with a design innovation called as design of plastic hinge relocation adopted from Guo[43] and other researchers[6-22]. A database was collected with specimens tested in failure mode of plastic hinge relocation or sliding shear. Several design recommandation was also collected to build the complete plastic hinge relocation design, basically referred from New Zealand design code NZS3101-2006. To perform the building structural analysis, commercial software ETABS and AutoDesk Revit was used.
By studying the measured values of the specimens with sliding shear failure adopted from references, it is concluded that sliding shear failure belongs to the brittle failure mode, and it often occurs after the specimen has the maximum load of the tested specimens, then the strength of the specimen drops suddenly. The statistical results show that when the shear stress is very high, the vertical sliding behavior of the specimen can be prevented by adding diagonal reinforcements.
In the design case study, using NZS3101 sliding shear design method and ACI318 shear friction design method to configure three different types of modified beams with plastic hinge relocation. Meanwhile, the reinforcement configurationwill be checked by the means of BIM for 3D visualization. In Case 1, with additional D29 bent-up rebar, the space between bending strengthening reinforcement and traditional shear design transverse reinforcement is smaller than Case 2 with combination of diagonal rebar and bent-up rebar. Considered about the steel bar constructability between Case 1 and Case2, it was recommended to utilize Case 2 to accomplish plastic hinge relocation design with sliding shear control. This will make not only reinforcement set up but also concrete casting become easier in-site. In Case3, the result shows the us longitudinal rebar can provide enough dowel force to resist shear friction, and the amount of reinforcement used in the three cases is the least, and the construction is easier. However, in this case, there is high risk for shear sliding due to the no diagonal rebar was placed. For the reason, for long-span beams with high shear sliding risk caused by high shear stress, it is recommended to adopt diagonal rebar configuration, and if the risk is low, it is recommended to adopt the form of shear friction method with longitudinal rebar as dowel bar. |
