無梁拱,拱(gong)形屋(wu)面被廣泛用(yong)于工業廠房、倉儲庫房、無(wu)梁拱(gong)體育場館、集貿市(shi)場、車庫機庫等，它(ta)無(wu)梁無(wu)擦、空間高大開闊，可以(yi)隨意分割組(zu)合，使用(yong)方便，自重輕、剛性強、彈性好、抗震性能優越等特點。
無梁拱(gong)(gong)(gong),拱(gong)(gong)(gong)形屋(wu)面還具有承(cheng)壓效果(guo)，拱(gong)(gong)(gong)所承(cheng)受(shou)的(de)荷載(zai)不同(tong)，其壓力曲線(xian)的(de)線(xian)形也(ye)不相同(tong)，一般按恒(heng)載(zai)下壓力曲線(xian)確定(ding);在活載(zai)作(zuo)用(yong)(yong)下，拱(gong)(gong)(gong)內(nei)力可能產生(sheng)彎(wan)矩，這(zhe)時(shi)鉸(jiao)的(de)設置(zhi)就會(hui)影響拱(gong)(gong)(gong)內(nei)彎(wan)矩的(de)分布狀況(kuang)。與(yu)剛架相仿，只有地(di)基(ji)良(liang)好或兩側拱(gong)(gong)(gong)肢處有穩定(ding)邊跨結構時(shi)才(cai)采(cai)用(yong)(yong)無鉸(jiao)拱(gong)(gong)(gong)，這(zhe)種拱(gong)(gong)(gong)很少用(yong)(yong)于房屋(wu)建筑(zhu)。雙鉸(jiao)拱(gong)(gong)(gong)應(ying)用(yong)(yong)較(jiao)多，為適應(ying)軟弱地(di)基(ji)上支座沉降(jiang)差及拱(gong)(gong)(gong)拉桿(gan)變(bian)形，最(zui)好采(cai)用(yong)(yong)靜定(ding)結構的(de)三鉸(jiao)拱(gong)(gong)(gong)
拱以曲桿抗(kang)衡并傳遞外力(li)給(gei)支(zhi)座(zuo)，故鉸支(zhi)座(zuo)不僅(jin)承(cheng)受(shou)豎(shu)向力(li)，并有相當大的(de)(de)(de)(de)水平向外的(de)(de)(de)(de)拱腳推(tui)(tui)力(li)，其合力(li)就(jiu)位于拱軸曲線在(zai)支(zhi)座(zuo)點(dian)的(de)(de)(de)(de)切線方(fang)向上。拱腳有推(tui)(tui)力(li)是其主要(yao)力(li)學特征之一，矢高f越小，推(tui)(tui)力(li)越大。一次超(chao)靜定的(de)(de)(de)(de)雙鉸拱，金(jin)屬屋(wu)面支(zhi)座(zuo)的(de)(de)(de)(de)垂直或水平位移均會引起內力(li)變化，對(dui)支(zhi)座(zuo)在(zai)推(tui)(tui)力(li)作用下無變位的(de)(de)(de)(de)要(yao)求就(jiu)更(geng)嚴格。由此可見，為了使拱保持正常(chang)工作，務必確保其支(zhi)座(zuo)能承(cheng)受(shou)住(zhu)推(tui)(tui)力(li)而(er)不位移，故拱腳推(tui)(tui)力(li)的(de)(de)(de)(de)結構(gou)處(chu)理(li)，是拱結構(gou)設計的(de)(de)(de)(de)中心問題。
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