50
施工技术
CONSTRUCTIONTECHNOLOGY
2013年1月下第42卷第2期
免装饰清水混凝土多棱角塔柱模板施工技术
于新华
（北京建工集团有限责任公司总承包部，北京100055）
[摘要】北京市昌平区南环大桥工程主桥结构形式为平行双索面三跨自锚式悬索桥，主桥7，8号墩为多棱角矩形塔柱，在建筑外观设计中采用免装饰清水混土设计理念，以取得自然质感的饰面效果。免装饰清水混凝土最终成型效果取决于模板选型，模板设计、加工、安装，节点细部处理，钢筋绑扎，混凝土配制、浇筑、振揭、养护等多种要
求。经方案比选，本工程采用大块钢模板倒模施工，保证了清水混凝土的成型效果。【关键词】混凝土；清水混凝土；模板；塔柱；施工技术
[中图分类号】TU755.2
【文献标识码】A
【文章编号】1002-8498(2013)02-0050-04
ConstructionoftheFormworkforMulti-angleTowerColumn
withDecoration-freeFair-facedConcrete
YuXinhua
(General Contract Department, Bejing Construction Engineering Group Co. , Lad. , Beijing 100055, China)
Abstract: The main structure of the South Ring Bridge in Changping District, Beijing is a three-span self-anchoring suspension bridge with double parallel cables. The No. 7 and No. 8 piers of the main bridge are multi-angle rectangular tower column, whose exterior surfaces take the idea of decoration-free fair-faced concrete to achieve a natural appearance. The ultimate forming effect of decoration-free fair-faced concrete depends on a number of factors including the formwork selection, formwork design, processing and installation, detailed treatment of joints, steel bars bonding, concrete preparation, concrete pouring, concrete vibration and maintenance. Through comparison of different formwork schemes, large steel formwork was selected and converse formwork construction method was used to achieve the satisfying forming effect of the concrete.
Key words:concrete; fair-faced concrete; formwork; tower column; construction
1工程概况
北京市昌平区南环路桥梁工程南环大桥位于昌平城东，该桥全长750m，桥宽43m，主桥全长 316m，跨径组成为70.5m+175m+70.5m。主桥结构形式为平行双索面三跨自锚式暴索桥，主桥分别在7,8号墩各设有2座主塔和2座辅塔。如图1 所示。
图1南环大桥主桥效果
Fig.1 Main bridge of South Ring Bridge in Beijing【作者简介】于新华，高级工程师，E-mail：191583033@qq.com
【收稿日期】2012-08-04 万方数据
2多棱角塔柱结构特点
南环大桥主塔为空心结构，柱高69.90m，分为 5段，塔座顶至主塔与横梁相交段底为第1段，为 4.3m×6.2m的矩形截面，高12.9m；主塔与横梁相交段，为5.5m×7.4m的矩形截面，高6.3m。下横梁顶至桥面顶为第2段，为3.6m×5.5m的矩形截面，高2.7m。桥面顶以上2.5m处为第3段，为 3.6m×6.0m的矩形截面，高2.5m。第4段为3.6m ×5.5m的矩形截面，高29.0m。第5段为3.0m× 4.6m的矩形截面，高8.0m。索鞍顶至塔顶为主塔钢结构装饰段。塔柱结构形式如图2所示。
由于塔柱阴、阳角较多且截面尺寸变化多，另外塔柱施工工期紧、截面尺寸较大、塔柱高度大、模板周转次数多，清水混凝土成型效果和景观要求高，给模板的设计、施工组织带来很大困难。