【单选题】
按承载力极限状态计算的表达式为:
①
<imgwidth="95"height="24"v:shapes="_x0000_i1042"src="http://wljy.whut.edu.cn:80/uploadfiles/word/GCJG1.files/image030.gif">
②
<imgwidth="107"height="24"v:shapes="_x0000_i1043"src="http://wljy.whut.edu.cn:80/uploadfiles/word/GCJG1.files/image032.gif">
③
<imgwidth="99"height="24"v:shapes="_x0000_i1044"src="http://wljy.whut.edu.cn:80/uploadfiles/word/GCJG1.files/image034.gif">
④
<imgwidth="99"height="24"v:shapes="_x0000_i1045"src="http://wljy.whut.edu.cn:80/uploadfiles/word/GCJG1.files/image034.gif">