钢纤维替代自密实混凝土梁箍筋的试验研究

Experimental Study on SCC Beams with Steel Fibers as Alternative of Stirrup

研究了用钢纤维替代箍筋时,集中荷载作用对自密实混凝土梁破坏形态的不同影响,同时分析了钢纤维部分或全部替代箍筋的可行性.主要试验参数包括纤维掺量(0,25,50 kg/m3)和配箍率(0,0.13%,0.22%).利用普通钢纤维混凝土梁的截面平均极限剪应力经验公式对试验结果进行分析,并与ACI 318—02,Eurocode 2,GB 50010—2002,CECS 38:2004等国内外标准进行了对比.结果表明:掺入钢纤维能显著提高梁的截面平均极限剪应力,当钢纤维掺量和箍筋含量达到一定值时,它们的共同作用可使梁的破坏形态从脆性转变为延性,因而钢纤维能够部分替代箍筋.

A series of self-compacting concrete beams were prepared with hooked steel fibers reinforced concrete with and without stirrups. Two-point symmetrically placed vertical load tests were carried out. The major test variables were the content of steel fibers（0, 25, 50 kg/m^3） and stirrup ratios（0, 0.13 %, 0.22%）. The test results show that the average ultimate shear stress is significantly increased with in- creasing fiber content, and the content of fibers in adequate percentage can change the brittle mode of fail- ure characterizing shear collapse into ductile failure mechanism, so the stirrups can be partly replaced by steel fibers. The ultimate shear strength determined experimentally is compared with the corresponding value deduced by semi-empirical expressions for normal concrete beams and GB 50010-2002, CECS 38： 2004, ACI 318-02, Eurocode 2.