鋼筋砼結構是目前國內最廣泛的結構形式,已有七、八十年曆史。它在造福人類、方便使用的同時,由於使用、weixiubudanghuojianzaozhiliangdengyuanyin,xuduofangwuchuxianlezheyanghuonayangdewenti,qizhonggeleijianzhuwuloudimianshunbandengfangxiangdeliefengwentifashengjiaoweipubian。tabujinshiloufangshiyongcunzaianquanyinhuan,erqieyingxiangguangan。
樓板順板裂縫(預製樓板)chanshenghoushidankuailoubanshouhehoubunenghuohennanshihezaixiangxianglinloubanchuandi,congerjianruoleloubanjiandexietongzuoyong,zhishidankuailoubandanxingbianxingzengjia,zhizuofuwanjuzengda,yinqizhizuochudezhuandong,bujunyunnaodushibanjianliefengchansheng,dankuaibandeguodubianxingjianghuishibandebiaomianchanshenglayingli,yinqidankuaibanbenshendehengxiangliefeng,yidanfashenggangjinhuayi,loubankailiejiazhong,gangjinyanghuaxiushicongerjiangdiloubandekekaodu。lingwaibandezhengtixingduijiegoudezhengtigangdu、抵di抗kang水shui平ping地di震zhen力li的de作zuo用yong是shi至zhi關guan重zhong要yao的de。總zong之zhi,順shun板ban的de裂lie縫feng將jiang會hui影ying響xiang建jian築zhu物wu的de使shi用yong功gong能neng和he結jie構gou的de安an全quan度du。今jin對dui裂lie縫feng產chan生sheng的de原yuan因yin提ti出chu以yi下xia觀guan點dian並bing闡chan述shu其qi防fang治zhi措cuo施shi。
1、預製樓麵板順板裂縫形成的原因
1.1地基不均勻沉降施工過程中沒有嚴格按設計及施工規範的要求進行施工。如:灰土基礎的灰土比例不正確、分層夯實不密實;幹容量達不到設計要求;接槎處理不當;地槽大麵積開挖,持力層土壤受到擾動而又末進行人工處理,砂土墊層施工中砂土含量偏高;濕(shi)陷(xian)性(xing)黃(huang)土(tu)地(di)基(ji)受(shou)水(shui)浸(jin)泡(pao)未(wei)加(jia)處(chu)理(li),毛(mao)石(shi)基(ji)礎(chu)組(zu)砌(qi)方(fang)法(fa)不(bu)正(zheng)確(que),整(zheng)體(ti)拉(la)接(jie)差(cha)均(jun)在(zai)不(bu)同(tong)程(cheng)度(du)上(shang)造(zao)成(cheng)地(di)基(ji)與(yu)基(ji)礎(chu)的(de)不(bu)均(jun)勻(yun)沉(chen)降(jiang),使(shi)主(zhu)體(ti)的(de)整(zheng)體(ti)剛(gang)度(du)造(zao)成(cheng)一(yi)定(ding)的(de)損(sun)失(shi),影(ying)響(xiang)到(dao)樓(lou)板(ban)的(de)整(zheng)體(ti)性(xing)。
shejiguochengzhongweiqieheshijikaolvdijidefuzaxing,bingmeiyouzhenduixingdicaiquhelidedijijichufangan,huozaijichushigongzuzhishejihuoduiyancaojiegoupanduanbuzhun,huoshejijichuleixingyudizhitiaojianbufu,hulvebiyaodedijixiawodechenjiangyansuan,douhuishijiegouzhengtigangdubuzu,zaochengjichudebujunyunchenjiang。
建jian築zhu物wu地di基ji的de不bu均jun勻yun沉chen降jiang形xing成cheng部bu位wei之zhi間jian沉chen降jiang差cha,使shi樓lou板ban支zhi點dian不bu能neng同tong步bu沉chen降jiang,加jia之zhi板ban上shang的de荷he載zai作zuo用yong產chan生sheng相xiang鄰lin板ban塊kuai之zhi間jian的de沉chen降jiang差cha致zhi使shi剪jian應ying力li集ji中zhong在zai板ban間jian板ban縫feng處chu,此ci處chu為wei取qu板ban間jian結jie合he部bu,也ye是shi板ban的de薄bo弱ruo環huan節jie必bi然ran形xing成cheng裂lie縫feng,而er且qie隨sui荷he載zai的de重zhong複fu擾rao動dong作zuo用yong,裂lie縫feng將jiang不bu斷duan開kai展zhan,最zui終zhong形xing成cheng順shun板ban裂lie縫feng。
1.2板縫本身的施工質量不佳
(1)板縫澆灌前,未進行衝刷或衝刷不淨影響板與縫內混凝土的結合。
(2)banfenghunningtuzhendaobushi,huozhimobuyan,zhendongpaojiangzhishimishidujiangdi,jianruolehunningtudeqiangdu,zhishibanyubanfengdejiehemianjijianxiao,congerjiangdikangjianqienengli。
(3)guanfenghunningtudecuguliaokelitaida,huobanfengtaixiao,shishiziguanchuanzhenggebanfengjiemian,yingxinlebandejiehenengli,kuangqiebanfengtaizhaixiao,banjianchenjiangchachuandijiejianjulitaiduan,jiangdileyikuaibanxianglingyikuaibanchuandihezaidenengli,zhishibanfengdejianyinglizengjiafenghunningtupeihebizhangwobuhao,shuihuibida,huoshuiniyongliangguoduo,yijibanfenghunningtuyanghubuhaozaochengshousuoliefeng。
(4)混(hun)凝(ning)土(tu)灌(guan)縫(feng)後(hou)強(qiang)度(du)沒(mei)有(you)達(da)到(dao)設(she)計(ji)強(qiang)度(du),就(jiu)受(shou)到(dao)施(shi)工(gong)荷(he)載(zai)的(de)擾(rao)動(dong),使(shi)板(ban)產(chan)生(sheng)撓(nao)曲(qu)變(bian)形(xing),由(you)於(yu)板(ban)縫(feng)混(hun)凝(ning)土(tu)強(qiang)度(du)低(di),板(ban)塊(kuai)協(xie)同(tong)傳(chuan)遞(di)能(neng)力(li)差(cha),也(ye)即(ji)是(shi)混(hun)凝(ning)土(tu)的(de)抗(kang)拉(la)剪(jian)能(neng)力(li)差(cha),形(xing)成(cheng)板(ban)縫(feng)。
(5)樓lou板ban安an裝zhuang時shi板ban未wei堵du板ban頭tou,板ban端duan錨mao固gu承cheng壓ya能neng力li低di,甚shen至zhi板ban頭tou被bei壓ya酥su碎sui,板ban內nei受shou力li鋼gang筋jin滑hua移yi,從cong而er增zeng加jia板ban的de撓nao度du及ji支zhi點dian轉zhuan動dong,加jia速su板ban縫feng開kai裂lie。板ban縫feng混hun凝ning土tu質zhi量liang差cha強qiang度du低di。
(6)板縫兩側樓麵板本身對受力反應不同步,撓度產生不同步,引起過大的剪應力。
2、預防順板裂縫產生的施工措施
2.1改善作業條件和施工工藝,嚴格控製施工質量
(7)做好基礎施工如灰土墊層中,應注意土顆粒的大小,灰土拌合的均勻程度;灰土虛輔厚度;灰土打夯遍數;灰土夯後幹容重實際數據;灰土施工縫的位置及留設是否規範;砂墊層中應控製砂的含泥量、振砂的密實度;機械大開挖地槽或地坑,應保證機械,開挖標高控製在設計標高30cm以上,30cm以下土方應用人工開挖,以防止對地基土的擾動。
毛石基礎的施工除應保證砂漿強度外,最重要是組砌方法,保證砌體整體性是毛石基礎施工的關鍵。
(8)樓板安裝質量樓板安裝前,應在牆體頂部用細石砼找平,板頭應堵嚴,板應座漿安放,板縫要離縫4cm.板縫澆注時應支底模,並應在板兩側刷素水泥漿,在底模上預澆0.5~1cm水泥砂漿後再灌縫,常溫下養護時間不低於7天,冬季施工除應摻加外加劑(防凍劑、減水劑)外,還應采取保暖措施,並應留出同條件之試塊(每一台班)以備檢驗砼之強度。
2.2加(jia)強(qiang)現(xian)場(chang)施(shi)工(gong)管(guan)理(li),嚴(yan)格(ge)責(ze)任(ren)製(zhi)度(du)施(shi)工(gong)部(bu)門(men)應(ying)加(jia)強(qiang)施(shi)工(gong)現(xian)場(chang)的(de)管(guan)理(li),建(jian)立(li)健(jian)全(quan)單(dan)位(wei)工(gong)程(cheng)質(zhi)量(liang)保(bao)證(zheng)體(ti)係(xi),各(ge)個(ge)施(shi)工(gong)環(huan)節(jie)及(ji)各(ge)分(fen)部(bu)分(fen)項(xiang)工(gong)程(cheng)的(de)工(gong)藝(yi)及(ji)質(zhi)量(liang)要(yao)層(ceng)層(ceng)把(ba)關(guan)。
3、順板裂縫的加固處理辦法
目前,對順板裂縫的加固處理辦法一般有兩個:加大截麵加固法和預應力加固法。
加大截麵加固法是根據原板的受力情況、構(gou)造(zao)特(te)點(dian)和(he)現(xian)場(chang)條(tiao)件(jian),選(xuan)用(yong)兩(liang)麵(mian)加(jia)厚(hou)或(huo)單(dan)麵(mian)加(jia)厚(hou)等(deng)構(gou)造(zao)形(xing)式(shi),施(shi)工(gong)時(shi),應(ying)將(jiang)存(cun)在(zai)缺(que)陷(xian)的(de)部(bu)位(wei)表(biao)麵(mian)鑿(zao)毛(mao)或(huo)打(da)成(cheng)溝(gou)槽(cao),並(bing)衝(chong)洗(xi)幹(gan)淨(jing),新(xin)舊(jiu)界(jie)麵(mian)處(chu)應(ying)以(yi)新(xin)鮮(xian)水(shui)泥(ni)或(huo)其(qi)他(ta)界(jie)麵(mian)劑(ji)進(jin)行(xing)處(chu)理(li),采(cai)用(yong)必(bi)要(yao)的(de)結(jie)構(gou)措(cuo)施(shi)和(he)施工工藝,確保新舊砼的整體工作。
預應力加固法是在基本不增加板厚不影響結構使用空間的條件下使用,有提高板的抗彎、kangjianchengzailihegaishanqizaishiyongjieduandexingneng,youyuyuyinglisuochanshengdefuwanjudixiaoyibufenhezaiwanju,shibanliefengkuandusuoxiaoshenzhiwanquanbihe,dadaojiaohaodexiaoguo。
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