浅谈桥梁施工技术与管理

2011级毕业设计（论文）题目：浅谈桥梁施工技术与管理专业：交通土建工程助学站点：湖南都市职业学院考籍号：911012101662姓名：朱国光指导教师：2013年3月浅谈桥梁施工技术与管理学生姓名：朱国光考籍号：911012101662站点：湖南都市职业学院指导教师：完成日期：2013年3月摘要根据自己在校的所学知识，对公路桥梁施工中常出现的质量问题及其成因进行了分析，重点对如何加强公路桥梁施工过程的质量管理进行了详细的阐述。对于公路桥梁施工的质量控制，广义上是指对建设项目全过程实施公路桥梁工程质量控制。随着我国经济的迅猛发展，公路桥梁建设在我国交通建设中占据着越来越重要的地位，其建设质量直接影响到我国公路交通线路的安全和正常运行。公路桥梁施工过程的特殊性决定必须对其施工质量进行管理和控制。一般的公路桥梁除了建设在城市高架桥外，大部分都是建设在环境条件较恶劣的山区或河流上。因此，必须对公路桥梁施工过程进行质量管理和控制，这不仅关系到国家经济建设的发展，也关系到人民生命财产的安全。关键词：公路桥梁，问题，成因分析，预应力，质量管理目录第1章公路桥梁施工中常出现的质量问题及其成因分析·······························11.1裂缝的形成及处理建议···········································································11.1.1温度变化引起的裂缝·······································································11.1.2地基基础变形引起的裂缝·································································11.1.3钢筋锈蚀引起的裂缝·······································································11.1.4表面处理法····················································································21.1.5填充法··························································································21.1.6结构补强法····················································································21.2桥梁的结构病害问题··············································································31.3局部蜂窝、麻面和气泡现象的出现····························································31.4混凝土施工养护····················································································31.4.1混凝土施工的一般要求····································································31.4.1.1炎热气候的混凝土施工··························································31.4.1.2冬季的混凝土施工································································41.4.2混凝土养护一般要求······································································41.4.3混凝土施工养护方法······································································51.4.3.1洒水养生···········································································51.4.3.2防水纸、塑料布养生····························································51.4.3.3蒸汽养生···········································································5第2章公路桥梁施工中预应力的应用························································52.1预应力钢绞线的选择···············································································52.2预应力结构砼开始张拉的时间问题····························································52.3预应力张拉的检查··················································································62.4预应力体系的设计··················································································62.5预应力孔道压浆质量的问题·····································································6第3章桥梁施工中的几个重要环节································································63.1钻孔灌注桩施工质量的控制···········································································73.2桥梁施工中的几个重要环节···········································································73.3梁板制作与安装质量的控制···········································································73.4桥面铺装质量的控························································································8第4章加强公路桥梁施工过程的质量管理·····················································84.1应重视结构的耐久性问题··············································································84.2加强混凝土质量管理·····················································································84.3充分重视桥梁的超载问题··············································································94.4加强混凝土质量管理·····················································································9结论···············································································································10致谢···············································································································11参考文献········································································································12第1页共12页第1章公路桥梁施工中常出现的质量问题及其成因分析1.1裂缝的形成及处理建议在公路桥梁的建造和使用中，常常因出现裂缝而严重影响工程质量甚至会出现桥梁垮塌的现象。所以克服和控制裂缝仍是亟待解决的问题。本文通过对混凝土桥梁裂缝产生的原因进行分析，并提出了可行性的处理方法。混凝土因其取材广泛、价格低廉，抗压强度高、可浇注成各种形状，并且耐火性好、不易风化、养护费用低，成为当今世界建筑结构中使用最广泛的建筑材料。但混凝土最主要的缺点是：抗拉能力差，容易开裂。混凝土裂缝不可避免，但它的危害程度是可以控制的。1.1.1温度变化引起的裂缝混凝土具有热胀冷缩的性质，当外部环境或结构内部温度发生变化，混凝土将发生变形，若变形遭到约束，则在结构内将产生应力，当应力超过混凝土抗拉强度时即产生温度裂缝。温度裂缝的特征主要是表面裂缝的走向一般无规律性，深层或贯穿裂缝的走向一般与主筋平行或接近平行；裂缝宽度大小不一，受温度变化的影响热细冷宽。表面温度裂缝常出现在现浇混凝土1d-2d之间，深层温度裂缝与贯穿温度裂缝常开始出现在现浇混凝土21d后。引起温度变化主要原因有：①表面温度裂缝多由于温差较大引起的。如大体积混凝土（厚度超过2m）浇筑之后由于水泥水化放热，致使内部温度很高，内外温差太大，导致表面出现裂缝。在冬季施工中，过早除掉保温层，或受寒潮袭击，都导致混凝土因早期强度低而产生裂缝。此外当预制构件采用蒸汽养护时，由于降温过快或构件急于出池，急带揭盖，均使混凝土表面收缩，产生裂缝。②深层贯穿裂缝多由于结构降温差值大，受外界的约束而引起的。如现浇桥台混凝土或大体积刚性扩大基础，浇筑在坚硬的地基上，未采取隔离等放松约束措施或收缩缝间距过大。在混凝土浇筑时，温度很高，加上水泥水化热的温度升高很大，使温度更高。当混凝土冷却收缩大拉应力，进而产生降温收缩裂缝；这类裂缝有时成贯穿状。1.1.2地基基础变形引起的裂缝由于基础竖向不均匀沉降或水平方向位移，使结构力，超出混凝土结构的抗拉能力，导致结构开裂。地基基础变形引起的裂缝常出现在钢筋上方，结构变化处，常开始出现在现浇混凝土10min到3h内。基础不均匀沉降的主要原因有：①由于混凝土在塑性状态下其基础、支架等有不均匀沉降，使局部混凝土变形受约束而产生裂缝。②由于重力作用使混凝土中较重颗料下沉而使水泥浆上浮，当这种下沉受到钢筋、模板作用时就会产生裂缝。1.1.3钢筋锈蚀引起的裂缝由于混凝土质量较差或保护层厚度不足，混凝土保护层受二氧化碳侵蚀碳化至钢第2页共12页筋表面，使钢筋周围混凝土碱度降低，或由于氯化物介入，钢筋周围氯离子含量较高，均可引起钢筋表面氧化膜破坏，钢筋中铁离子与侵入到混凝土中氧气和水分发生锈蚀反应，其锈蚀物氢氧化铁体积比原