預張(zhang)法和預應(ying)力施工方法及(ji)注意(yi)事項

1、張緊作(zuo)(zuo)業前應(ying)在四周設(she)置警示牌，并(bing)設(she)置專人(ren)(ren)看管現場安全。底座兩(liang)(liang)端的(de)兩(liang)(liang)根外(wai)側鋼絞線之間呈45度(du)角呈扇形輻射(she)狀危險區(qu)。張拉(la)、錨(mao)固作(zuo)(zuo)業人(ren)(ren)員必須站(zhan)在安全邊上，嚴禁圍觀者(zhe)和閑散人(ren)(ren)員進入張拉(la)作(zuo)(zuo)業區(qu)，以防(fang)鋼絞線斷裂、卡箍(gu)滑(hua)落傷人(ren)(ren)。

2、張(zhang)緊操作人員不宜頻繁(fan)更(geng)換，應保持相對(dui)穩定并經過(guo)培訓。

3、臨時(shi)用(yong)電(dian)要(yao)求全(quan)部(bu)采用(yong)“三相五線(xian)”接(jie)線(xian)，每個臨時(shi)配電(dian)板（箱(xiang)）必須全(quan)部(bu)安裝敏感漏電(dian)保護器。

4、各種電(dian)(dian)(dian)機(ji)機(ji)械必(bi)須(xu)有接地裝置。定期檢查，確保沒有故障后再開始(shi)使用。在停電(dian)(dian)(dian)或下班休息時，必(bi)須(xu)關(guan)閉并鎖定制(zhi)動器。電(dian)(dian)(dian)機(ji)嚴格按(an)照(zhao)“一機(ji)一制(zhi)動系統”接線。

5、現場施工(gong)時，施工(gong)設備電(dian)(dian)(dian)源(yuan)、照明電(dian)(dian)(dian)源(yuan)、辦(ban)公(gong)電(dian)(dian)(dian)源(yuan)、電(dian)(dian)(dian)燈(deng)電(dian)(dian)(dian)源(yuan)必須分別標明電(dian)(dian)(dian)板。斷開電(dian)(dian)(dian)源(yuan)時，由專職(zhi)電(dian)(dian)(dian)工(gong)負責，其他人員(yuan)不得隨(sui)意斷開。

6、如遇暴(bao)風(feng)雨、雷雨、濃霧和6級(ji)以上大風(feng)，應停止施工。施工方法(fa)

7、鋼(gang)(gang)絞(jiao)線(xian)切割(ge)長(chang)度(du) 鋼(gang)(gang)絞(jiao)線(xian)切割(ge)前(qian)，應根據底座設備的(de)具體情(qing)況進行材(cai)料切割(ge)。在計(ji)算切割(ge)長(chang)度(du)時(shi)應考慮(lv)基座的(de)長(chang)度(du)、錨(mao)固夾(jia)具的(de)長(chang)度(du)和外露長(chang)度(du)。切割(ge)時(shi)，先將鋼(gang)(gang)絞(jiao)線(xian)拉直，然后用(yong)鋼(gang)(gang)尺測量進行切割(ge)。下料在平(ping)坦的(de)場(chang)地上進行，并用(yong)磨床(chuang)切割(ge)。剪斷(duan)點兩(liang)側5cm處用(yong)鐵(tie)絲(si)捆扎，防止剪斷(duan)后股線(xian)散開。反(fan)了。每根鋼(gang)(gang)絞(jiao)線(xian)的(de)兩(liang)端(duan)應做(zuo)標(biao)記(ji)和編(bian)號，塑(su)料管(guan)應在成(cheng)束穿線(xian)后按圖紙標(biao)記(ji)進行預應力破壞處理。、

8、張(zhang)拉程序張(zhang)拉程序為0→初始應力→σcon（荷載下(xia)錨(mao)固(gu)2min），其中(zhong)σcon為張(zhang)拉過程中(zhong)的控制應力值，包括預應力損失。

9、用(yong)(yong)(yong)(yong)理(li)論(lun)(lun)(lun)(lun)伸(shen)長(chang)(chang)(chang)率(lv)計(ji)算(suan)張(zhang)(zhang)(zhang)(zhang)(zhang)力(li)(li)(li)(li)時(shi)，應(ying)(ying)測(ce)量(liang)(liang)實(shi)際伸(shen)長(chang)(chang)(chang)率(lv)值，并與(yu)理(li)論(lun)(lun)(lun)(lun)伸(shen)長(chang)(chang)(chang)率(lv)值核(he)對。預(yu)(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)(li)筋理(li)論(lun)(lun)(lun)(lun)伸(shen)長(chang)(chang)(chang)值計(ji)算(suan)公式： 式中： pp——預(yu)(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)(li)鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)的(de)(de)平均拉(la)(la)(la)力(li)(li)(li)(li)（n） l——預(yu)(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)(li)鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)的(de)(de)長(chang)(chang)(chang)度(du)(du)（cm） ap——截面(mian)積預(yu)(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)(li)鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)的(de)(de)彈性(xing)模量(liang)(liang)（mm2） ep——預(yu)(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)(li)鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)的(de)(de)彈性(xing)模量(liang)(liang)（n/mm2）。假設(she)有兩(liang)(liang)(liang)種類型的(de)(de)張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)器(qi)：64、5 米和(he) 52、5 米。張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)平臺鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)有效(xiao)長(chang)(chang)(chang)度(du)(du)=張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)平臺長(chang)(chang)(chang)度(du)(du)+兩(liang)(liang)(liang)根鋼(gang)(gang)(gang)梁寬度(du)(du)+減壓(ya)沙箱(xiang)(xiang)(xiang)(xiang)長(chang)(chang)(chang)度(du)(du)+兩(liang)(liang)(liang)端(duan)錨(mao)(mao)(mao)(mao)桿長(chang)(chang)(chang)度(du)(du)64、5米，張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)有效(xiao)長(chang)(chang)(chang)度(du)(du)平臺鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)l=64、5+1、3+0、5 +0、1=66、4m 理(li)論(lun)(lun)(lun)(lun)伸(shen)長(chang)(chang)(chang)值δl=×66、4×÷(1、95×)=.5m 鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)在(zai)張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)臺上的(de)(de)有效(xiao)長(chang)(chang)(chang)度(du)(du)l=52、5+1、3++0、1=54、理(li)論(lun)(lun)(lun)(lun)伸(shen)長(chang)(chang)(chang)值δl=×54、24×÷(1、95×)=，預(yu)(yu)(yu)(yu)應(ying)(ying)力(li)(li)(li)(li)梁張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)施工(gong)采(cai)用(yong)(yong)(yong)(yong)一(yi)端(duan)固(gu)定，單向張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)：張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)順序從(cong)中間向兩(liang)(liang)(liang)側對稱進行(xing)，荷(he)載(zai)進行(xing)分三(san)個(ge)階段出來(lai)(lai)。張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)操作人(ren)員應(ying)(ying)有3人(ren)，1人(ren)用(yong)(yong)(yong)(yong)鋼(gang)(gang)(gang)尺測(ce)量(liang)(liang)鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)的(de)(de)實(shi)際伸(shen)長(chang)(chang)(chang)值，1人(ren)記錄，1人(ren)操作油(you)泵。整體(ti)張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)：在(zai)整體(ti)張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)端(duan)，用(yong)(yong)(yong)(yong)兩(liang)(liang)(liang)個(ge)千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)推動(dong)(dong)(dong)活動(dong)(dong)(dong)錨(mao)(mao)(mao)(mao)箱(xiang)(xiang)(xiang)(xiang)進行(xing)整體(ti)張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)。為(wei)了在(zai)張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)過程中保持活動(dong)(dong)(dong)錨(mao)(mao)(mao)(mao)箱(xiang)(xiang)(xiang)(xiang)的(de)(de)平衡，采(cai)用(yong)(yong)(yong)(yong)兩(liang)(liang)(liang)臺千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)油(you)路(lu)聯動(dong)(dong)(dong)，同(tong)步頂(ding)(ding)(ding)(ding)升的(de)(de)方法(fa)。當(dang)張(zhang)(zhang)(zhang)(zhang)(zhang)力(li)(li)(li)(li)達到(dao)80%時(shi)，由于千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)行(xing)程小，無法(fa)達到(dao)計(ji)算(suan)伸(shen)長(chang)(chang)(chang)值。需要(yao)在(zai)活動(dong)(dong)(dong)錨(mao)(mao)(mao)(mao)箱(xiang)(xiang)(xiang)(xiang)和(he)固(gu)定錨(mao)(mao)(mao)(mao)箱(xiang)(xiang)(xiang)(xiang)之(zhi)間使(shi)(shi)用(yong)(yong)(yong)(yong)大塊(kuai)來(lai)(lai)保持行(xing)程，千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)回(hui)油(you)，在(zai)千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)下加(jia)兩(liang)(liang)(liang)片(pian)。間隔，然后(hou)拉(la)(la)(la)伸(shen)到(dao) %。張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)完(wan)成(cheng)(cheng)后(hou)，用(yong)(yong)(yong)(yong)螺母錨(mao)(mao)(mao)(mao)定錨(mao)(mao)(mao)(mao)桿，將油(you)回(hui)油(you)到(dao)千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)，松(song)開連接套，即可將活動(dong)(dong)(dong)錨(mao)(mao)(mao)(mao)箱(xiang)(xiang)(xiang)(xiang)和(he)千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)移至另一(yi)條生產線(xian)(xian)張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)。首先檢查(cha)油(you)路(lu)是(shi)否正常，檢查(cha)安全設(she)施，確保人(ren)員安全。每(mei)個(ge)油(you)泵的(de)(de)驅動(dong)(dong)(dong)器(qi)緊(jin)(jin)(jin)(jin)(jin)(jin)密配合，控制各(ge)自的(de)(de)油(you)泵。當(dang)拉(la)(la)(la)力(li)(li)(li)(li)達到(dao)%σk時(shi)，負(fu)載(zai)保持5分鐘后(hou)回(hui)縮，再拉(la)(la)(la)至%σk。標記股線(xian)(xian)，放松(song)壓(ya)力(li)(li)(li)(li)并重(zhong)新(xin)緊(jin)(jin)(jin)(jin)(jin)(jin)張(zhang)(zhang)(zhang)(zhang)(zhang)。張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)完(wan)成(cheng)(cheng)后(hou)，重(zhong)新(xin)校準(zhun)用(yong)(yong)(yong)(yong)于張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)的(de)(de)張(zhang)(zhang)(zhang)(zhang)(zhang)緊(jin)(jin)(jin)(jin)(jin)(jin)機器(qi)和(he)設(she)備。觀察并測(ce)量(liang)(liang)基座和(he)壓(ya)力(li)(li)(li)(li)柱。加(jia)鋼(gang)(gang)(gang)塞(sai)(sai)(sai)做支撐，千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)卸(xie)荷(he)，在(zai)承重(zhong)箱(xiang)(xiang)(xiang)(xiang)和(he)端(duan)梁之(zhi)間插入不(bu)同(tong)粗細的(de)(de)鋼(gang)(gang)(gang)塞(sai)(sai)(sai)，用(yong)(yong)(yong)(yong)細鋼(gang)(gang)(gang)塞(sai)(sai)(sai)塞(sai)(sai)(sai)緊(jin)(jin)(jin)(jin)(jin)(jin)，使(shi)(shi)錨(mao)(mao)(mao)(mao)桿受力(li)(li)(li)(li)均勻(yun)，然后(hou)千(qian)(qian)(qian)(qian)斤(jin)(jin)(jin)頂(ding)(ding)(ding)(ding)卸(xie)載(zai)。鋼(gang)(gang)(gang)絞(jiao)線(xian)(xian)拉(la)(la)(la)長(chang)(chang)(chang)后(hou)，將失(shi)(shi)效(xiao)管密封，防止混(hun)凝(ning)土(tu)澆筑時(shi)混(hun)凝(ning)土(tu)漿料倒回(hui)失(shi)(shi)效(xiao)管內(nei)，影響失(shi)(shi)效(xiao)效(xiao)果。混(hun)凝(ning)土(tu)澆筑必(bi)須在(zai)張(zhang)(zhang)(zhang)(zhang)(zhang)拉(la)(la)(la)后(hou)48小時(shi)內(nei)完(wan)成(cheng)(cheng)。

(1)錨(mao)具(ju)安裝：先安裝被動受拉端(duan)部錨(mao)具(ju)，將同一組中(zhong)的每根(gen)鋼絞線拉直(zhi)，然(ran)后安裝主動受拉端(duan)部錨(mao)具(ju)，然(ran)后緊固(gu)兩端(duan)錨(mao)銷。安裝時應(ying)由(you)專(zhuan)人操作，并嚴格(ge)檢查錨(mao)具(ju)，錨(mao)具(ju)型號(hao)應(ying)符(fu)合要求(qiu)。

(2)安裝(zhuang)(zhuang)千(qian)(qian)斤(jin)頂；千(qian)(qian)斤(jin)頂在(zai)使(shi)用前應(ying)進行檢(jian)查和檢(jian)查，每個(ge)千(qian)(qian)斤(jin)頂應(ying)有油泵(beng)檢(jian)查曲線。將千(qian)(qian)斤(jin)頂放入(ru)承重箱并安裝(zhuang)(zhuang)到位(wei)。千(qian)(qian)斤(jin)頂的(de)安裝(zhuang)(zhuang)位(wei)置(zhi)應(ying)保(bao)證千(qian)(qian)斤(jin)頂的(de)作用線與工(gong)字鋼(gang)受(shou)壓(ya)柱(zhu)的(de)質心一(yi)致。

(3)預(yu)張(zhang)(zhang)(zhang)(zhang)緊(jin)：檢查安裝的(de)千斤頂配套設(she)備(bei)各部件是否齊全(quan)，是否符合標準。啟動(dong)油泵進行(xing)初(chu)張(zhang)(zhang)(zhang)(zhang)緊(jin)，向千斤頂張(zhang)(zhang)(zhang)(zhang)緊(jin)油缸注油。初(chu)始張(zhang)(zhang)(zhang)(zhang)力(li)(li)控(kong)制應力(li)(li)為 10% σk。張(zhang)(zhang)(zhang)(zhang)拉(la)(la)前應在鋼絞(jiao)線上畫一個標記作(zuo)為原始記錄(lu)點。拉(la)(la)力(li)(li)達到(dao)控(kong)制應力(li)(li)后(hou)，頂針(zhen)錨固卸(xie)荷。在張(zhang)(zhang)(zhang)(zhang)拉(la)(la)過程中，每組鋼絞(jiao)線應對稱(cheng)張(zhang)(zhang)(zhang)(zhang)緊(jin)，保證底座受力(li)(li)平衡，標線準確(que)、清晰。調整拉(la)(la)力(li)(li)的(de)步驟(zou)和技術要(yao)求(qiu)與(yu)(yu)初(chu)始拉(la)(la)力(li)(li)相同，只是拉(la)(la)應力(li)(li)調整為40%σk。另(ling)外，應將張(zhang)(zhang)(zhang)(zhang)拉(la)(la)后(hou)的(de)鋼絞(jiao)線的(de)張(zhang)(zhang)(zhang)(zhang)拉(la)(la)值與(yu)(yu)理論(lun)計算值進行(xing)比較，兩者之差不應大于(yu)5%，滿足以上要(yao)求(qiu)后(hou)，方(fang)可(ke)進行(xing)整體張(zhang)(zhang)(zhang)(zhang)拉(la)(la)工作(zuo)。

(4)當混凝土試件達到(dao)設(she)計強度的80%以上時(shi)(shi)，方可釋放。釋放時(shi)(shi)，油(you)泵(beng)的加載(zai)必須緩慢，每個油(you)泵(beng)的油(you)位讀(du)數(shu)應(ying)(ying)略有(you)不同(tong)，千斤頂的卸載(zai)時(shi)(shi)間不應(ying)(ying)少于此。

(5)切(qie)(qie)(qie)(qie)割(ge)(ge)鋼絞線：鋼絞線切(qie)(qie)(qie)(qie)口應靠(kao)近構件，最好相距1-2cm，并(bing)應使用砂輪(lun)鋸切(qie)(qie)(qie)(qie)割(ge)(ge)，嚴禁(jin)電焊(han)。如果用氧-乙炔火焰(yan)切(qie)(qie)(qie)(qie)割(ge)(ge)，切(qie)(qie)(qie)(qie)割(ge)(ge)時火焰(yan)不應燒傷構件表面，切(qie)(qie)(qie)(qie)割(ge)(ge)處裸露的(de)鋼絞線必須(xu)涂上防(fang)銹漆，并(bing)用與構件相同標簽的(de)混凝土堵住。