（一）、斗拱的組成

    斗拱在結構上由四種部件組成。

     1、拱。與建筑(zhu)物表面平行的(de)弓形構(gou)件。

     2、翹(qiao)。與建筑物(wu)表面(mian)垂直或成45度或60度夾角(jiao)的弓形(xing)構件。其(qi)形(xing)式與拱相同(tong)，唯放置(zhi)方向不同(tong)。

     3、昂。昂在(zai)唐、宋時是斗拱中的(de)斜置構件，起杠桿作用(yong)(yong)，這是真昂。明清時昂的(de)結構作用(yong)(yong)下降，常(chang)常(chang)僅起裝飾作用(yong)(yong)。其形式(shi)為將翹向外的(de)一端(duan)特別(bie)加長，并斜向下垂（或斜向上挑出）。

     4、斗與(yu)升。斗與(yu)升都是斗形的(de)(de)立方塊(kuai)。位(wei)于拱(gong)(gong)(gong)(gong)的(de)(de)兩端，界于上下(xia)兩層拱(gong)(gong)(gong)(gong)或(huo)拱(gong)(gong)(gong)(gong)與(yu)枋(fang)之(zhi)間(jian)著，清代叫(jiao)“升”。位(wei)于翹或(huo)昂(ang)的(de)(de)兩端，界于上下(xia)兩層翹昂(ang)，或(huo)包括橫(heng)拱(gong)(gong)(gong)(gong)之(zhi)間(jian)者，叫(jiao)做(zuo)(zuo)“斗”。斗和升除位(wei)置不(bu)同外，在全部設有橫(heng)拱(gong)(gong)(gong)(gong)的(de)(de)斗拱(gong)(gong)(gong)(gong)中，升上只(zhi)承托與(yu)建筑(zhu)物表面平行(xing)的(de)(de)拱(gong)(gong)(gong)(gong)或(huo)枋(fang)一種構件，所(suo)以只(zhi)開一面口(kou)，叫(jiao)做(zuo)(zuo)“順身口(kou)”；而斗拱(gong)(gong)(gong)(gong)則承托相交(jiao)的(de)(de)拱(gong)(gong)(gong)(gong)與(yu)翹昂(ang)，所(suo)以斗上開的(de)(de)是“十字口(kou)”。

   （二）、斗拱的分類及各部分名稱

   ; 1、按斗拱(gong)在建筑(zhu)物上所處的部(bu)分可以分為兩大類。

     （1）、外檐斗拱(gong)。主要包括五種。

A、柱頭斗拱。直接座于(yu)柱頭上。宋代叫做(zuo)“柱頭鋪(pu)作”，清(qing)代稱“柱頭科”。

B、柱間(jian)(jian)斗(dou)拱。位于兩柱之間(jian)(jian)的額枋(fang)或平(ping)板(ban)枋(fang)上。宋(song)代(dai)(dai)叫做“補間(jian)(jian)鋪作”，清代(dai)(dai)稱“平(ping)身(shen)科”。

C、轉(zhuan)角斗拱。位于(yu)角柱上。宋(song)代(dai)叫做“角鋪作(zuo)”，清(qing)代(dai)稱“角科”。

D、溜(liu)金斗(dou)拱。在明清時期由帶下昂的(de)平身(shen)科斗(dou)拱轉化而來。

E、平座斗拱(gong)。位于(yu)平座下(xia)面，用于(yu)支撐平座。

每一組斗拱(gong)，宋代(dai)(dai)叫做“一朵”，清代(dai)(dai)稱(cheng)“一攢”。

（2）、內檐斗拱(gong)。主要包(bao)括品字科斗拱(gong)和隔(ge)架斗拱(gong)兩大類。

          2、拱(gong)的(de)分(fen)類及(ji)各部分(fen)名稱

（1）、按拱(gong)所處的(de)結構位置可分為兩大(da)類(lei)。現(xian)以外檐斗拱(gong)為例(li)做(zuo)介紹(shao)。

A、正心(xin)拱。凡是位于檐(yan)柱中線上(shang)的拱，都叫(jiao)“正心(xin)拱”。

正(zheng)心(xin)拱(gong)(gong)(gong)一面向外一面向里。在拱(gong)(gong)(gong)的(de)(de)縱(zong)中線上(shang)需(xu)加寬0.3－0.25斗(dou)口(kou)的(de)(de)槽口(kou)，用以安(an)放拱(gong)(gong)(gong)墊(dian)板。所以正(zheng)心(xin)拱(gong)(gong)(gong)的(de)(de)厚(hou)(hou)度要比其(qi)它的(de)(de)拱(gong)(gong)(gong)多一個拱(gong)(gong)(gong)墊(dian)板的(de)(de)厚(hou)(hou)度。

B、單(dan)材(cai)(cai)拱(gong)(gong)(gong)。凡(fan)不(bu)在(zai)檐(yan)柱中心(xin)線上的拱(gong)(gong)(gong)都叫“單(dan)材(cai)(cai)拱(gong)(gong)(gong)”。在(zai)檐(yan)柱中心(xin)線以(yi)外的單(dan)材(cai)(cai)拱(gong)(gong)(gong)又(you)叫“外拽拱(gong)(gong)(gong)”；在(zai)檐(yan)柱中心(xin)線以(yi)內的單(dan)材(cai)(cai)拱(gong)(gong)(gong)又(you)叫“里拽拱(gong)(gong)(gong)”。

 （2）、按拱(gong)(gong)(gong)(gong)的長(chang)短(duan)尺寸可分為(wei)三類：瓜(gua)(gua)拱(gong)(gong)(gong)(gong)、萬(wan)(wan)拱(gong)(gong)(gong)(gong)和(he)廂拱(gong)(gong)(gong)(gong)。瓜(gua)(gua)拱(gong)(gong)(gong)(gong)最短(duan)，廂拱(gong)(gong)(gong)(gong)次(ci)之，萬(wan)(wan)拱(gong)(gong)(gong)(gong)最長(chang)。這(zhe)是(shi)清代(dai)的規定。瓜(gua)(gua)拱(gong)(gong)(gong)(gong)和(he)萬(wan)(wan)拱(gong)(gong)(gong)(gong)常相(xiang)疊(die)并用，瓜(gua)(gua)拱(gong)(gong)(gong)(gong)在下，萬(wan)(wan)拱(gong)(gong)(gong)(gong)在上，瓜(gua)(gua)拱(gong)(gong)(gong)(gong)托著萬(wan)(wan)拱(gong)(gong)(gong)(gong)。位(wei)于正(zheng)心拱(gong)(gong)(gong)(gong)位(wei)置上的瓜(gua)(gua)拱(gong)(gong)(gong)(gong)叫做“正(zheng)心瓜(gua)(gua)拱(gong)(gong)(gong)(gong)”（宋代(dai)稱(cheng)泥道拱(gong)(gong)(gong)(gong)）；位(wei)于正(zheng)心拱(gong)(gong)(gong)(gong)位(wei)置上萬(wan)(wan)拱(gong)(gong)(gong)(gong)叫做“正(zheng)心萬(wan)(wan)拱(gong)(gong)(gong)(gong)”。位(wei)于單材(cai)拱(gong)(gong)(gong)(gong)位(wei)置上的瓜(gua)(gua)拱(gong)(gong)(gong)(gong)和(he)萬(wan)(wan)拱(gong)(gong)(gong)(gong)，分別叫做“單材(cai)瓜(gua)(gua)拱(gong)(gong)(gong)(gong)”、“單材(cai)萬(wan)(wan)拱(gong)(gong)(gong)(gong)”。又可以分為(wei)“外拽瓜(gua)(gua)拱(gong)(gong)(gong)(gong)”、“外拽萬(wan)(wan)拱(gong)(gong)(gong)(gong)”和(he)“里拽瓜(gua)(gua)拱(gong)(gong)(gong)(gong)”、“里拽萬(wan)(wan)拱(gong)(gong)(gong)(gong)”。

廂拱(gong)(gong)(gong)總(zong)是安放在最上(shang)層翹或昂兩端，外(wai)拽廂拱(gong)(gong)(gong)承(cheng)托(tuo)挑檐枋，里拽廂拱(gong)(gong)(gong)承(cheng)托(tuo)天花枋。在正心拱(gong)(gong)(gong)位置不會出現廂拱(gong)(gong)(gong)，所以廂拱(gong)(gong)(gong)沒有正心和單(dan)材(cai)之別。

瓜(gua)拱、萬拱、廂拱是清代的名稱。在宋代瓜(gua)拱稱“瓜(gua)子拱”，萬拱稱“慢拱”，廂拱稱“令拱”。

  （3）、拱的各部分名稱。

在(zai)拱(gong)(gong)(gong)(gong)的(de)中間部位有與翹(qiao)、昂(ang)或要(yao)頭相(xiang)交的(de)卯(mao)口(kou)。拱(gong)(gong)(gong)(gong)的(de)兩端(duan)有承托升的(de)分(fen)位。在(zai)升與卯(mao)口(kou)之間，拱(gong)(gong)(gong)(gong)向(xiang)下彎(wan)(wan)曲的(de)位置(zhi)叫(jiao)做“拱(gong)(gong)(gong)(gong)眼”。拱(gong)(gong)(gong)(gong)的(de)兩端(duan)下面曲卷(juan)處叫(jiao)“彎(wan)(wan)拱(gong)(gong)(gong)(gong)”。彎(wan)(wan)拱(gong)(gong)(gong)(gong)的(de)曲度在(zai)清代《營造法式(shi)》里有“瓜四”、“萬三”、“廂五(wu)”的(de)規定，使拱(gong)(gong)(gong)(gong)彎(wan)(wan)分(fen)成幾小段直線，以便(bian)制作。