Eom Gi-Ha, Kim Sung Jae, Lee Tae-Hee, Kim Jang-Ho Jay
School of Civil and Environmental Engineering, Yonsei University, Seoul 03722, Korea.
Materials (Basel). 2017 Mar 13;10(3):283. doi: 10.3390/ma10030283.
A recent trend in bridge construction has been the optimization of the cost-to-performance ratio. The most effective way to optimize the cost-to-performance ratio is to maximize the efficiency of the superstructure. Currently, many bridge engineers and designers favor two- or three- girder plate superstructures, due to their cost advantages. However, research on the performance enhancements of the I-type girder in two- or three- girder plate bridges is lacking. One of the most important performance improvement technologies for the I-type girder is the "preflex" method. In the preflex method, the specimen is inverted during the construction process to apply prestressed cambering to the specimen by using self-weight. However, a problem with the preflex construction method is difficulty with inverting the girder/plate system during the concrete curing process. Therefore, a new inverting system called Turn-Over (TO) wheel was proposed. Using TO wheels, wider variations to the I-type girder design can be achieved. Using this TO construction method, various cross sectional designs of girder plate systems can be considered due to its easiness in inverting the girder/plate system. In this study, the location of concrete confinement sections between the steel I-beams and concrete plates was varied in an I-girder cross-sectional design. Design parameters included effective height, flange thickness, flange width, confining concrete section width, etc. From this study, the optimum cross-sectional design of the I-girder/concrete plate system was achieved. Then, a single 20 m TO girder/plate system and two 20 m TO girder bridges were constructed and tested to evaluate their performance. From the test, failure behavior, load carrying capacity, crack pattern, etc., are obtained. The results are discussed in detail in this paper.
桥梁建设的一个最新趋势是优化性价比。优化性价比的最有效方法是使上部结构的效率最大化。目前，许多桥梁工程师和设计师青睐两梁或三梁板式上部结构，因其具有成本优势。然而，关于两梁或三梁板桥中工字梁性能提升的研究尚缺。工字梁最重要的性能改进技术之一是“预弯”法。在预弯法中，在施工过程中将试件倒置，利用自重对试件施加预应力起拱。然而，预弯施工法存在的一个问题是在混凝土养护过程中难以倒置梁/板系统。因此，提出了一种名为翻转（TO）轮的新型翻转系统。使用TO轮，可以实现对工字梁设计更广泛的变化。采用这种TO施工法，由于其易于倒置梁/板系统，可考虑梁板式系统的各种横截面设计。在本研究中，在工字梁横截面设计中改变了钢工字梁与混凝土板之间混凝土约束段的位置。设计参数包括有效高度、翼缘厚度、翼缘宽度、约束混凝土截面宽度等。通过本研究，实现了工字梁/混凝土板系统的最佳横截面设计。然后，建造并测试了一个20米的单跨TO梁/板系统和两座20米的TO梁桥，以评估其性能。通过试验，获得了破坏行为、承载能力、裂缝模式等。本文对结果进行了详细讨论。
