Submitted on: 18 December 2007.
Revised on: 27 January 2008.
Accepted on: 06 March 2008.
___________________Frontiers of Structural and Civil Engineering
http://reply.papertrans.cn/2/103/10269/10269-32.png
Submitted on: 04 May 2018.
Revised on: 20 August 2018.
Accepted on: 09 October 2018.
___________________Frontiers of Structural and Civil Engineering
http://reply.papertrans.cn/2/103/10269/10269-34.png
http://reply.papertrans.cn/2/103/10269/10269-35.png
http://reply.papertrans.cn/2/103/10269/10269-36.png