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| Research on the Control Technoloy in Cracking Prevention of 100 Meter High H - type Cable Tower |
| LIU Jin - yan1，HU Guo - wei2 |
| (1. Shanxi University，Taiyuan，Shanxi 030013，China; 2. China Railway No. 3 Engineering Group Co. Ltd，Taiyuan， Shanxi 030001， China) |
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Abstract Abstract ： Research purposes ： The temperature rise of concrete is caused by hydration thermal effect while concrete segment of the main tower is pouring. As the temperature of concrete is gradually decreased with time，descending speed of temperature in each position is uneven， the relative temperature difference is formed， because of constraints in anterior segment， under the action of temperature difference，shrinkage and creep， early age cracking is more prominent. Meanwhile， the bending moment on the bottom of tower column is very big under the action of weight and external load，the concrete is compressed on one side and is pulled on the other side，the crack may be caused by the misconduct of construction. The main tower of Yujiang Super Major Bridge has a vase - like shape and large dimension， which requires high survey precision. In this paper， taking construction of cable pylon of Yujiang Bridge as example， based on the element software ANSYS modeling to solve structure internal force calculation， the thermal analysis and structural analysis of tlie first segment are selected as example，twenty calculation cases are presented in construction of cable pylon，force condition and stress distribution of different calculation cases are analyzed. The concrete measures in cracking prevention of 100 meter high H - type cable tower are proposed according to analysis results of the early hydration rffect and later force condition of cable tower，to provide reference for similar projects. Research conclusions ：( 1) The paper analyzes the early hydration thermal effect of tlie first segment by finite element sofeware，the formula of temperature deformation is derived， calculations of the formula are in good agreement with results of finite element sofeware，adding ice to concrete is a cooling measure. (2) The tie rod of bottom columns is established in design position，the two balancing rods of middle tower columns are established in design position，the force condition of cable tower is effectively improved by these measures. ( 3 ) The comparison result of calculated value and measured value of tlie key section measuring point shows that the stress state which is simulated by finite element software follows the same trends as the actual situation，results are in good agreement. (4) The research result can provide reference for control project in cracking prevention of 100 meter high H - type cable to^wer.
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Received: 08 September 2016
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2017, Vol. 34 
