既有无粘结预应力钢绞线重锚截断技术研究与实践

发布时间：2019-04-17 21:43

【摘要】：随着城市规划的不断变化,许多现有的建筑物为了满足城市建设的发展或者使用功能上新的要求,需要在已经建立无粘结预应力的楼板上开洞或者对整体结构中不满足使用需求的部分进行改造或拆除,以满足建筑物新的需求,为此需把已有的预应力筋截断。但以往的施工工序是直接截断预应力筋,会由于预应力损失过大,可能导致施工期间原建筑物存在较大安全隐患。这种情况需要使用特制开口锚具。本文通过试验研究与实践,创新性地提出了一种既有无粘结预应力混凝土结构改造钢绞线重锚后截断的施工方法,在改造实施过程中,能基本维持原有结构的预应力不损失或损失很小。该施工方法的关键在于研发了一种简单高效的开口锚具,分别为工具锚(杯内带螺纹)和工作锚(杯内双夹片),工作锚为永久锚具,工具锚为可重复使用的工具锚具。本文对开口锚具进行了静力试验、长期锚固试验、重复荷载试验和钢绞线截断试验。为研究楼盖截断前后开口锚具结构内力与变形情况和钢绞线截断前后应力改变情况,采用有限元ABAQUS软件对开口锚具和钢绞线进行三维非线性数值模拟,重点研究截断前后开口锚具和钢绞线应力分布情况。结合具体试验和有限元理论分析,对既有无粘结预应力混凝土结构改造钢绞线重锚施工的具体施工工法做了详细介绍并对汇源大厦裙楼拆除工程做了信息化监控。理论分析表明:既有无粘结预应力钢绞线重锚截断技术开口锚具试验有限元模拟的计算结果与试验结果较好的吻合。试验研究和工程实践表明,钢绞线切断时应将工作锚和工具锚配合使用才能达到最佳锚固效果,最好是2个工具锚配合1个工作锚使用,切断完成后工具锚可拆卸重复使用。结合长沙汇源大厦裙楼拆除工程,提出了既有无粘结预应力钢绞线重锚截断技术的施工工法和信息化监控方案。
[Abstract]:With the changing of urban planning, many existing buildings, in order to meet the development of urban construction or new requirements on the use function, need to be modified or removed in the part where there is no pre-stressed pre-stressed floor or the part that does not meet the use requirement in the overall structure, In order to meet the new demands of the building, the existing prestressed reinforcement needs to be cut off. However, the conventional construction process is to cut the pre-stressed bar directly, which can lead to a large potential safety hazard in the original building during the construction period due to the excessive prestress loss. This situation requires the use of a specially-made open anchorage. Based on the experimental research and practice, this paper presents an innovative construction method for reconstructing the heavy anchor of a steel strand with a non-bonded pre-stressed concrete structure, and in the course of the transformation, it is possible to maintain the pre-stress of the original structure without loss or loss. The key to the construction method is to develop a simple and efficient open anchorage device, which is a tool anchor (in-cup thread) and a working anchor (double-clip in the cup), and the working anchor is a permanent anchorage device, and the tool anchor is a reusable tool anchor. In this paper, the static test, the long-term anchorage test, the repeated load test and the steel strand cut-off test are carried out for the open anchorage. In order to study the internal force and deformation of the open anchorage structure before and after the cut-off of the floor, and the stress change before and after the cut-off of the steel strand, the finite element ABAQUS software is used to simulate the three-dimensional nonlinear numerical simulation of the open anchorage and the steel strand, and the stress distribution of the open anchorage and the steel strand before and after the cut-off is mainly studied. Combined with the concrete test and the finite element theory analysis, the concrete construction method of the existing non-bonded pre-stressed concrete structure modified steel strand reanchor construction is introduced in detail, and the construction of the podium building of the Huiyuan Building is information-controlled. The theoretical analysis shows that the results of the finite element simulation of the open anchorage device with non-bonded pre-stressed steel strand are in good agreement with the experimental results. The test research and engineering practice show that the work anchor and the tool anchor should be used in combination to achieve the best anchoring effect when the steel strand is cut off. It is preferable that the two tool anchors are used with one working anchor, and the tool anchor can be used repeatedly after the cutting is completed. Combined with the demolition of the podium building of the Changsha Huiyuan Building, the construction method and the information monitoring scheme of the existing non-bonded pre-stressed steel strand heavy-anchor cutting technology are put forward.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU757

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