無梁拱,拱(gong)形屋面被廣泛(fan)用于工業廠房、倉儲庫(ku)房、無(wu)梁拱(gong)體(ti)育場(chang)館(guan)、集貿(mao)市(shi)場(chang)、車庫(ku)機庫(ku)等，它無(wu)梁無(wu)擦、空間高大開闊，可以隨意(yi)分割組合(he)，使用方(fang)便，自重輕(qing)、剛(gang)性(xing)強、彈性(xing)好、抗震性(xing)能優越等特點。
無梁拱(gong)(gong)(gong)(gong),拱(gong)(gong)(gong)(gong)形(xing)屋面(mian)還具有(you)承壓效(xiao)果(guo)，拱(gong)(gong)(gong)(gong)所承受(shou)的(de)(de)荷(he)載不(bu)(bu)同，其壓力曲線的(de)(de)線形(xing)也(ye)不(bu)(bu)相同，一(yi)般按恒載下壓力曲線確定;在活載作用(yong)下，拱(gong)(gong)(gong)(gong)內力可能產生彎矩，這(zhe)時(shi)鉸的(de)(de)設(she)置就會影響(xiang)拱(gong)(gong)(gong)(gong)內彎矩的(de)(de)分布狀(zhuang)況。與(yu)剛架相仿，只有(you)地(di)基良(liang)好或兩(liang)側拱(gong)(gong)(gong)(gong)肢處(chu)有(you)穩定邊跨(kua)結構時(shi)才采用(yong)無鉸拱(gong)(gong)(gong)(gong)，這(zhe)種拱(gong)(gong)(gong)(gong)很少用(yong)于房屋建(jian)筑。雙(shuang)鉸拱(gong)(gong)(gong)(gong)應(ying)用(yong)較多，為適(shi)應(ying)軟(ruan)弱(ruo)地(di)基上(shang)支座(zuo)沉降差及拱(gong)(gong)(gong)(gong)拉桿變形(xing)，采用(yong)靜(jing)定結構的(de)(de)三鉸拱(gong)(gong)(gong)(gong)。
拱(gong)(gong)(gong)(gong)以曲桿(gan)抗(kang)衡并傳遞外力(li)(li)(li)(li)給支(zhi)(zhi)座(zuo)，故鉸(jiao)支(zhi)(zhi)座(zuo)不(bu)僅承(cheng)受豎向力(li)(li)(li)(li)，并有(you)相當大的(de)水平向外的(de)拱(gong)(gong)(gong)(gong)腳(jiao)推(tui)力(li)(li)(li)(li)，其合力(li)(li)(li)(li)就位于拱(gong)(gong)(gong)(gong)軸(zhou)曲線在(zai)支(zhi)(zhi)座(zuo)點的(de)切(qie)線方向上。拱(gong)(gong)(gong)(gong)腳(jiao)有(you)推(tui)力(li)(li)(li)(li)是其主要力(li)(li)(li)(li)學特(te)征之一(yi)，矢高(gao)f越(yue)小，推(tui)力(li)(li)(li)(li)越(yue)大。一(yi)次(ci)超靜定(ding)的(de)雙鉸(jiao)拱(gong)(gong)(gong)(gong)，金(jin)屬屋面支(zhi)(zhi)座(zuo)的(de)垂直或水平位移均會(hui)引(yin)起內力(li)(li)(li)(li)變化，對支(zhi)(zhi)座(zuo)在(zai)推(tui)力(li)(li)(li)(li)作用下無(wu)變位的(de)要求就更(geng)嚴格。由此(ci)可見，為了使拱(gong)(gong)(gong)(gong)保持(chi)正常工作，務(wu)必確保其支(zhi)(zhi)座(zuo)能承(cheng)受住推(tui)力(li)(li)(li)(li)而不(bu)位移，故拱(gong)(gong)(gong)(gong)腳(jiao)推(tui)力(li)(li)(li)(li)的(de)結構處(chu)理，是拱(gong)(gong)(gong)(gong)結構設(she)計(ji)的(de)中(zhong)心問題。
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