Effect of concrete cracks on dynamic characteristics of powerhouse for giant-scale hydrostation |
| |
| Authors: | Ziqin Tian Yunliang Zhang Zhenyue Ma Jing Chen |
| |
| Institution: | 1. Huazhong University of Science and Technology, Wuhan 430074, China
2. Dalian University of Technology, Dalian 116024, China |
| |
| Abstract: | With the increase of capacity and size of the hydro-generator unit, the spiral case becomes a more super-giant hydraulic structure
with very high HD value, where H and D denote water head and maximum intake diameter of spiral case, respectively. Due to the induced lower stiffness by the more
giant size and adverse operation conditions, dynamic performances of the powerhouse and the supporting structure for the giant
units have become more important and attracted much attention. If the manner of steel spiral case embedded directly in concrete
is adopted, on some locations of the concrete surrounding the spiral case, distributed and concentrated cracks will emerge
due to high tensile stress. Although the concrete is reinforced well to control the maximum crack width, definitely these
cracks will reduce the local and entire stiffness of the powerhouse. Under dynamic loads such as hydraulic forces including
water pressure pulsation in flow passage acting on the structure, effect of the cracks on the dynamic characteristics of the
local members and entire structure needs to be evaluated. However, research on this subject is few in hydroelectric engineering.
In this paper, Three-Gorge Project was taken as an example to evaluate effect of such cracks on natural frequencies and the
vibration responses of the powerhouse under hydraulic and earthquake forces in detail. Results show that cracks only reduce
the local structural stiffness greatly but have little effect on the entire powerhouse especially the superstructure; vibrations
of powerhouse with cracks in concrete surrounding the spiral case are still under the design limits. Results in this paper
have been verified by practice of Three-Gorge Project.
Supported by National Natural Science Foundation of China (No.50679009) and Foundations for Young Teachers in Dalian University
of Technology(No.893219).
TIAN Ziqin, born in 1965, male, doctoral student, senior engineer. |
| |
| Keywords: | giant-scale hydrostation powerhouse concrete crack dynamic characteristics numerical simulation |
| 本文献已被 维普 万方数据 SpringerLink 等数据库收录！ |
|
