無梁拱,拱形屋(wu)面被廣泛用于工業廠房(fang)、倉儲庫房(fang)、無(wu)梁拱體育場(chang)館、集(ji)貿市場(chang)、車庫機庫等，它無(wu)梁無(wu)擦、空間高大開(kai)闊(kuo)，可以隨(sui)意分割組合，使用方便，自重輕、剛性(xing)強、彈(dan)性(xing)好(hao)、抗震(zhen)性(xing)能優越等特點。
無(wu)梁拱(gong)(gong),拱(gong)(gong)形(xing)屋(wu)面還具有承(cheng)壓(ya)(ya)效(xiao)果，拱(gong)(gong)所承(cheng)受的(de)(de)(de)荷載(zai)不同，其(qi)壓(ya)(ya)力曲線(xian)的(de)(de)(de)線(xian)形(xing)也不相同，一般(ban)按恒(heng)載(zai)下(xia)壓(ya)(ya)力曲線(xian)確(que)定;在活載(zai)作用下(xia)，拱(gong)(gong)內力可(ke)能(neng)產生彎矩，這時鉸(jiao)的(de)(de)(de)設置就(jiu)會影響拱(gong)(gong)內彎矩的(de)(de)(de)分布狀況(kuang)。與(yu)剛架相仿，只有地基良好或兩側拱(gong)(gong)肢處有穩(wen)定邊跨結構(gou)時才采用無(wu)鉸(jiao)拱(gong)(gong)，這種(zhong)拱(gong)(gong)很少用于(yu)房屋(wu)建筑。雙鉸(jiao)拱(gong)(gong)應(ying)用較多，為(wei)適應(ying)軟弱地基上(shang)支(zhi)座沉降差及拱(gong)(gong)拉桿變形(xing)，好采用靜定結構(gou)的(de)(de)(de)三(san)鉸(jiao)拱(gong)(gong)。
拱(gong)(gong)(gong)以曲桿抗衡(heng)并傳遞外力(li)給支(zhi)(zhi)座(zuo)(zuo)(zuo)，故鉸支(zhi)(zhi)座(zuo)(zuo)(zuo)不(bu)僅(jin)承受豎向(xiang)力(li)，并有相當大(da)的(de)(de)水平向(xiang)外的(de)(de)拱(gong)(gong)(gong)腳推力(li)，其(qi)合力(li)就(jiu)位于(yu)拱(gong)(gong)(gong)軸曲線(xian)在支(zhi)(zhi)座(zuo)(zuo)(zuo)點的(de)(de)切線(xian)方向(xiang)上。拱(gong)(gong)(gong)腳有推力(li)是其(qi)主要力(li)學特征之一，矢高f越小，推力(li)越大(da)。一次超靜定的(de)(de)雙(shuang)鉸拱(gong)(gong)(gong)，金屬屋面支(zhi)(zhi)座(zuo)(zuo)(zuo)的(de)(de)垂(chui)直或水平位移均會引起內力(li)變化，對(dui)支(zhi)(zhi)座(zuo)(zuo)(zuo)在推力(li)作用下無變位的(de)(de)要求就(jiu)更嚴格。由此可見，為了使拱(gong)(gong)(gong)保(bao)持正常工作，務(wu)必(bi)確保(bao)其(qi)支(zhi)(zhi)座(zuo)(zuo)(zuo)能承受住推力(li)而不(bu)位移，故拱(gong)(gong)(gong)腳推力(li)的(de)(de)結構處理，是拱(gong)(gong)(gong)結構設計的(de)(de)中心問題(ti)。
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