無梁(liang)拱(gong)施(shi)工工藝流程及操(cao)作(zuo)要點
1、無梁拱工藝流程
無梁拱(gong)(gong)建(jian)立拱(gong)(gong)形屋(wu)面測(ce)量控制網及測(ce)量控制 → 主拱(gong)(gong)支撐架體設計→ 主拱(gong)(gong)吊(diao)裝及拱(gong)(gong)形屋(wu)面安(an)裝 → 卸荷
2、無梁拱操作要點
大跨度鋼(gang)無(wu)梁(liang)拱(gong)(gong)拱(gong)(gong)形(xing)(xing)屋面安裝(zhuang)(zhuang)同(tong)時(shi)涉及分段及吊機(ji)的(de)(de)(de)選擇(ze)、施工測量定位、支撐架體的(de)(de)(de)設臵、鋼(gang)無(wu)梁(liang)拱(gong)(gong)的(de)(de)(de)吊裝(zhuang)(zhuang)及拱(gong)(gong)形(xing)(xing)屋面安裝(zhuang)(zhuang)、卸荷(he)等多種拱(gong)(gong)形(xing)(xing)屋面施工工藝，而(er)鋼(gang)無(wu)梁(liang)拱(gong)(gong)的(de)(de)(de)吊裝(zhuang)(zhuang)及拱(gong)(gong)形(xing)(xing)屋面安裝(zhuang)(zhuang)是整個施工過程的(de)(de)(de)關鍵。
2.1、建立(li)測(ce)(ce)量控制網(wang)及(ji)測(ce)(ce)量控制
1.GPS點(dian)(dian)(dian)(dian)的交接及(ji)復(fu)核
根據(ju)(ju)GPS點(dian)(dian)(dian)(dian)的成(cheng)(cheng)果(guo)(guo)，制(zhi)定點(dian)(dian)(dian)(dian)位精度的復(fu)查，具體測(ce)量(liang)步驟：根據(ju)(ju)GPS點(dian)(dian)(dian)(dian)的布(bu)(bu)局，在(zai)施工(gong)(gong)區域邊布(bu)(bu)設(she)(she)二級控(kong)(kong)制(zhi)網，按閉合導線的觀(guan)測(ce)方(fang)法，計算(suan)(suan)出導線精度，再根據(ju)(ju)計算(suan)(suan)出的點(dian)(dian)(dian)(dian)位精度，如果(guo)(guo)GPS點(dian)(dian)(dian)(dian)的成(cheng)(cheng)果(guo)(guo)符合施工(gong)(gong)要(yao)(yao)求即(ji)可(ke)使(shi)用，反之(zhi)要(yao)(yao)對導線實行(xing)平(ping)差后才可(ke)使(shi)用;對水準(zhun)點(dian)(dian)(dian)(dian)的復(fu)查，采用國家二級水準(zhun)的要(yao)(yao)求進行(xing)復(fu)查，在(zai)施工(gong)(gong)區域內按施工(gong)(gong)需要(yao)(yao)布(bu)(bu)設(she)(she)若干固定的水準(zhun)基準(zhun)點(dian)(dian)(dian)(dian)，對布(bu)(bu)設(she)(she)的水準(zhun)點(dian)(dian)(dian)(dian)實行(xing)聯(lian)測(ce)。
建立施工(gong)(gong)控(kong)(kong)制(zhi)網(有(you)軸(zhou)線控(kong)(kong)制(zhi)樁)，形(xing)成(cheng)(cheng)統一布(bu)(bu)局
2.2、施工中的測量控制
1.主拱(gong)跨度(du)大，對于四(si)個主拱(gong)與地面接觸(chu)點的(de)控(kong)制精度(du)要求相對高，在二級導(dao)線的(de)基礎上用(yong)極坐標法(fa)放樣出四(si)個接觸(chu)點，建立(li)一(yi)矩形導(dao)線閉合環，用(yong)距離、角(jiao)度(du)復(fu)核精度(du);
2.主拱(gong)為斜平面主拱(gong)，在測量控制上采用(yong)直角相(xiang)交觀測法(fa);
3.主拱(gong)(gong)采用(yong)分段拱(gong)(gong)形屋面安(an)裝，在二級控制基(ji)礎上布臵方(fang)格網，對(dui)桁架節點進行控制
4.高程測(ce)量(liang)
依據現場(chang)的(de)(de)已知水(shui)準(zhun)點(dian)(dian)，在施工場(chang)區內測(ce)設(she)水(shui)準(zhun)基準(zhun)點(dian)(dian)，水(shui)準(zhun)點(dian)(dian)的(de)(de)密度(du)應為100m左右(you)一個，水(shui)準(zhun)路(lu)(lu)線構成附和路(lu)(lu)線，以(yi)便(bian)校核，觀測(ce)精度(du)要(yao)(yao)(yao)滿足四等水(shui)準(zhun)的(de)(de)要(yao)(yao)(yao)求(qiu)，閉合差(cha)要(yao)(yao)(yao)小(xiao)于(L為線路(lu)(lu)長，以(yi)千米計;n為測(ce)站數。)
5.變(bian)形觀(guan)測
在確認施工拱(gong)形屋(wu)面(mian)(mian)安(an)(an)裝(zhuang)準(zhun)確后(hou)(hou)，以拱(gong)形屋(wu)面(mian)(mian)安(an)(an)裝(zhuang)監(jian)測所測定的(de)(de)每個標(biao)志點的(de)(de)實(shi)際坐(zuo)標(biao)和高(gao)程(cheng)作為基準(zhun)值(zhi)。以后(hou)(hou)每隔2周按拱(gong)形屋(wu)面(mian)(mian)安(an)(an)裝(zhuang)監(jian)測時用同(tong)精度的(de)(de)觀(guan)測方法對標(biao)志點進(jin)行觀(guan)測，計算出坐(zuo)標(biao)和高(gao)程(cheng)與基準(zhun)值(zhi)進(jin)行比較，從(cong)而確認鋼架頂部的(de)(de)變(bian)形情況。直至建(jian)筑物封頂看不見標(biao)志點后(hou)(hou)，變(bian)形觀(guan)測結(jie)束。
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