大跨度连续钢混组合梁中支点顶升施工技术

Middle Fulcrum Jacking Construction Technology for Long-Span Continuous Steel-Concrete Composite Beams

摘要:

大跨度连续钢混组合梁中支点处混凝土桥面板由于墩顶负弯矩作用长期处于受拉状态，易开裂，导致钢筋锈蚀，影响结构耐久性。通过对中支点进行顶升施工，可有效降低墩顶桥面板拉应力，避免中支点处桥面板开裂，确保混凝土桥面板在运营过程中的质量与使用功能。以某大跨径连续钢混组合梁中支点顶升施工为背景，详细阐述了运用PLC液压同步顶升系统进行顶升施工的关键技术，包括千斤顶型号选型、顶升设备选型、顶升设备布置、临时支点布置、试顶升要点、正式顶升关键步骤及施工过程监测等，旨在为同类型工程施工提供有价值的技术参考。

Abstract:

The concrete bridge deck at the middle fulcrum of the long-span continuous steel-concrete composite beam is constantly under tension for a long time due to the negative bending moment at the pier top, which makes it prone to cracking, leading to steel bar corrosion and affecting the durability of the structure. By jacking the middle fulcrum, the tensile stress of the bridge deck at the pier top can be effectively reduced, avoiding cracking of the bridge deck at the middle fulcrum, and ensuring the quality and using function of the concrete bridge deck during the operation process. Taking the middle fulcrum jacking construction of a long-span continuous steel-concrete composite beam as the background, the key technologies for the jacking construction using a PLC hydraulic synchronous jacking system are elaborated in detail, including selection of jack types, selection of jacking equipment, layout of jacking equipment, arrangement of temporary fulcrums, key points of trial jacking, key steps of formal jacking and monitoring of construction process, aiming to provide the technical references for the construction of similar projects.