主跨400m的UHPC连续梁桥优化设计

发布时间：2018-01-15 09:52

本文关键词：主跨400m的UHPC连续梁桥优化设计　出处：《公路交通科技》2014年08期 　论文类型：期刊论文

【摘要】：利用超高性能混凝土(UHPC)的优越性能,提出了与之相适应的新型箱梁结构,目的是利用材料的高强度及新结构的轻型化,解决常规混凝土连续箱梁桥易开裂、下挠和自重过大、跨径难以突破300 m的难题。在原有工作的基础上,对主跨400 m的UHPC连续箱梁桥进行了整体性能分析及优化设计,优化内容包括桥梁边跨长度、梁高、板厚等主要参数,以得到其合适的取值范围,根据优化结果建议:边跨与主跨跨径比范围为0.55~0.65;中支点梁高与主跨跨径比范围为1/20~1/25;跨中梁高与支点梁高比范围为1/1.8~1/2.3。整体性能分析结果表明:运用UHPC及新结构,能轻松实现连续梁桥400 m跨径的突破,并具有较大的整体刚度及安全储备。综合考虑长期社会经济效益,在主跨跨径300~500 m范围内,该新型结构可与斜拉桥、悬索桥等其他桥型形成强有力的竞争选型方案。
[Abstract]:Based on the superior performance of UHPC, a new type of box girder structure is put forward, which aims to make use of the high strength of materials and the light weight of new structure. To solve the problem that the conventional concrete continuous box girder bridge is easy to crack, the deflection and self-weight is too large, and the span is difficult to break through 300m, on the basis of the original work. The overall performance analysis and optimization design of UHPC continuous box girder bridge with main span of 400m are carried out. The optimization contents include bridge side span length, beam height, plate thickness and other main parameters to get the appropriate value range. According to the result of optimization, it is suggested that the ratio of side span to main span is 0.55 ~ 0.65; The ratio of height to span of middle fulcrum beam is 1 / 20 / 1 / 25; The ratio of beam height to fulcrum beam height is 1 / 1 / 1 / 2. 3. The result of overall performance analysis shows that the breakthrough of 400m span of continuous beam bridge can be easily realized by using UHPC and new structure. It also has a large overall stiffness and safety reserve. Considering the long-term social and economic benefits, the new structure can be combined with the cable-stayed bridge within the main span of 300 ~ 500m. Suspension bridges and other bridges form a strong competitive selection scheme.
【作者单位】：湖南大学;国防科技大学;
【基金】：国家自然科学基金项目(51378194) 广东省交通运输厅科技项目(2013-02-036)
【分类号】：U442.5
【正文快照】： 0引言大跨径预应力混凝土连续箱梁桥存在着梁体易开裂和跨中长期下挠难控制等问题[1—21,巳成为其跨径进一步突破的技术瓶颈,究其主要原因有(1)自重过大,而普通混凝土的抗拉强度很低;(2)在长期荷载作用下,普通混凝土的徐变系 (a)?短数较大,由此产生过大的徐变下挠。未来的大桥

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