體外預(yù)應(yīng)力筋極限應(yīng)力公式的評(píng)價(jià)分析

1、體外預(yù)應(yīng)力筋極限應(yīng)力公式的評(píng)價(jià)分衣Zfl：收蚩幼的INY外48體外兩點(diǎn)力Li、/數(shù)冊(cè)展礎(chǔ)上.利用上述極限應(yīng)力公式分別進(jìn)行試算，并采用統(tǒng)訃分析的方法，希盥檢驗(yàn)上述備公式f勺計(jì)算結(jié)果劇實(shí)驗(yàn)給果的物令情況.并推薦出適令于橋梁工程計(jì)算腫體外預(yù)咸力極限應(yīng)力計(jì)算方法.已收集各組試驗(yàn)梁數(shù)搬見(jiàn)長(zhǎng)2-2.體外預(yù)應(yīng)力筋極限應(yīng)力的計(jì)算與實(shí)驗(yàn)梁實(shí)測(cè)值的比值的統(tǒng)計(jì)分析結(jié)果見(jiàn)表輩九抄號(hào)跨島ItKMiu雀方氏<rfAlSA1-114.3938.15晦中fiu戦A2-214.29IS15跨中fiu拔直線A3-314293S15跨中Hl扱Ab214293S.15理中加戟A2-214.3*3S.15瘠中如載頁(yè)純A3-214

2、耳38,15瞬中in鞍31-213333S15般點(diǎn)加載肌折線H2-213333S1533-21333JS.15雙點(diǎn)扔報(bào)屈濟(jì)大學(xué)A-12031.24祗點(diǎn)加戟A-2202了51戯點(diǎn)m鞍B-1203124飆點(diǎn)加撥聯(lián)折線B-22027.51啦點(diǎn)加按MA-0416597聯(lián)點(diǎn)加鞍MA-Q516537既點(diǎn)Hi報(bào)MB*012053般點(diǎn)U1戦般折級(jí)MB-022052.9般點(diǎn)加投般折線MD-032050.1聯(lián)慮Ml戦MB-042050.1狀點(diǎn)加嶽哈T大HGD-12037.94雙點(diǎn)Hi戟IK卞、-試驗(yàn)單位編號(hào)跨高比碇換度加裁方或布索形式哈工大HGD-22039.19雙點(diǎn)加找雙折線HGD-42036.S2雙點(diǎn)加找雙折

3、拔HGD-52036.16雙點(diǎn)辦1栽雙析線HGD-62031.87雙點(diǎn)加核雙折線HGD-72031.62雙點(diǎn)加戟雙折線HGD-92034.7S單點(diǎn)加技雙折線HGD-102030.S6雙點(diǎn)加叔雙折拔HGD-112032.74雙點(diǎn)加我雙折線HGD-122035.7収點(diǎn)加裁私析線HGD-132042.73雙折銭HGD-142036.92雙點(diǎn)加找雙折線HGD-16202S.S2雙點(diǎn)加戟雙折找HGD-172030.82單點(diǎn)加找雙折線HGD-1S2034.5S雙點(diǎn)加叔雙折坡HGD-192035S9雙點(diǎn)加疲雙折線HGD-202045.6雙點(diǎn)加戦雙折線KW16.228雙點(diǎn)加戟雙折歧KW26.12S雙點(diǎn)加核雙折

4、線KW3628雙點(diǎn)加拔雙折線KW4628雙點(diǎn)加找雙折線KW-56.12S雙點(diǎn)加叔雙折找KW66.32S雙點(diǎn)加戰(zhàn)雙折線KH.TaiiTO16.526.3雙點(diǎn)加載伍線ri16.525.99雙點(diǎn)加戟瞅轉(zhuǎn)向T-216.523.1雙點(diǎn)加找雙轉(zhuǎn)肉T-1A13.224.4雙點(diǎn)加找T-1D13.225.23雙點(diǎn)加找單折線TUB16.521.SI雙點(diǎn)加找農(nóng)2-3極隕狀態(tài)下計(jì)口應(yīng)力仃實(shí)測(cè)應(yīng)力的比值集號(hào)A；粘結(jié)AASHTO-04Harajli文伙16文娥34文眥36英國(guó)規(guī)范ACI-Q2ClwkrabaitiA1-10.101.000.970.830.920.620.610.61a8iA2-20.670.970.S6

5、0.790.S90.620.5S0.600.73A3-30.670.990.790.7S0.910.650.560.610.71A1-20.71lm0.790.S30.930.630.620.620.S2A2-20.690.990.S5OSO0.910.630.590.610.75A3-20.701.021.000.S10.940.670.5S0.630.74B1-20.630.7S0.730.740.750.570.650.600.69B2-20.610.770.710.720.730.560.630.5S0.66B3-20.63OSO0.700.730.760.600.630.610.66

6、A-10.990.S60.S11.040.S60.950.92OSS0.93A20.920.S10.660.950.S1OSS0.860.S30.S7B-11.221.010.7S1.351.011.201.050.971.07B-21.120.9S1.111.150.991.071.Q51.021.06HGD-11.Q50.931.261.290.901.040.930.S50.9SHGD21.090.951.351.410.911.0S0.940.S41.01HGD-41.010.911.231.21OSS1.020.900.S30.93HGD-5O.W0.S61.191.090.840.

7、990.850.800.S6HGD-60.S30.S51.171.040.S30.9S0.S30.7S0.S4HGD-70.990.921.141.090.901.0S0.S90.S50.90HGD91.221.121.1S1.391.091.301.091.031.11HGD-100.950.S91.151.060.S61.030.S60.S20.S7HGD-110.S90.S41.140.970.S10.99OSO0.7S0.S2HGD-120.S90.S41.120.970.820.970.820.790.S3HGD-131.131.031.201.331.001.191.Q20.971

8、.04HGD-140.530.S51.191.060.S20.9S0.S30.790.S4HGD-160.90071.140.970.S41.010.S30.S10.S4HGD-171.Q31.001.121.100.9S1.150.970.950.9SHGD-1S0.92OSS1.110.990.S61.010.S60.S30.S7續(xù)農(nóng)23梁號(hào)無(wú)粘結(jié)AASHTO-04HarajliZ16文紙34文抵36英國(guó)規(guī)范ACI-Q2ClkrabarbHGD-190.910.S91.130.9S0.S71.040.S50.S50.S9HGD-200.950.901.121.05O.SS1.050.S90

9、.S70.92T00.790.921.100.S90.910.900770.S5Q86T-10.750.S71.110.S50.S60.S60.720.S00.S1T-20.400.541.410.530.520.5S0.230.390.42TJA0.410.541.530.490.520.3S0.290.340.39T-1D0.730.911.200.790.S90.730.000.740.76TJB0.6S0.S41.11O.SO0.S30.S30.650.7S0.79KW-11.151.12KW21.060.96KW30.960.S9KW40.920.S6KW51.060.96KW61.

10、231.15MA-040&0.S71.130.780.S40.910.520.77O.SOMA-050690.S51.13O.SO0.S30.S90.510.740.77MB-010.620.791.120.720.790.810.360.710.74MB-020&0.S61.120.740.S40.970.390.7SO.SOMB-030.420.641.140.520.620.770.200.570.59MB-040.5S0.S61.120.710.S41.000.36O.SO0.S2均（ft0.S2O.SS1.070.950.S5O.SS0.770.790.S2方堆0.0

11、40.010.040.040.010.040.W0.030.02離笊系救0.050.020.040.040.010.050.Q50.030.03注*表中均值為極附應(yīng)力的計(jì)鼻值A(chǔ)實(shí)測(cè)值.為計(jì)件公式對(duì)試驗(yàn)梁失效.原因?yàn)樵圂徚嚎绺弑绕?公式不適用.在統(tǒng)訛分析中若以有效預(yù)應(yīng)力、話裁應(yīng)力増債分別計(jì)件相對(duì)渓差較犬.可達(dá)20%左右.綜合表2-3研究結(jié)果町認(rèn)為影響體外預(yù)應(yīng)力筋極限應(yīng)力增雖的工要因素令受拉區(qū)普通鋼筋的面積.體外預(yù)應(yīng)力鋼筋的面積,跨高比.混凝土強(qiáng)度.外荷我形式及布索形式等六項(xiàng)。在其他影響因素不變的悄況卜，體外預(yù)應(yīng)力鋼筋的應(yīng)力增嚴(yán)隨著跨島比的増加而降低,隨著混凝土標(biāo)號(hào)的増加而增加。綜合配筋指標(biāo)對(duì)極

12、限應(yīng)力增園的影響表現(xiàn)為存在一個(gè)合理的配筋指標(biāo)便得梁體在破壞時(shí)普通制筋的應(yīng)變達(dá)到0.01的同時(shí)，受兒M頂邊混凝土的應(yīng)變達(dá)到0,003.即兩者同時(shí)失效而導(dǎo)致梁體破壞。十綜合配筋指標(biāo)小于臨界值時(shí)，體外預(yù)應(yīng)力鋼筋的應(yīng)力增雖隨若觀筋血積的増人而增大，十綜合配筋指標(biāo)人于這-臨界狀態(tài)時(shí)，體外預(yù)應(yīng)力#的應(yīng)力増盤(pán)BB著配筋面積的增大而減小。從文獻(xiàn)18試驗(yàn)中B系列梁與A系列梁的極限應(yīng)力增量差值，以及文獻(xiàn)6中91317號(hào)試驗(yàn)梁的極限應(yīng)力增呈試驗(yàn)結(jié)果來(lái)作，加我方式的影響很大，其差值人致在一倍左右.布索形成對(duì)體外預(yù)W力筋極限血力壇址的彩響主要衣現(xiàn)為二次效何的澎響.在工桎設(shè)計(jì)中這種影響町通過(guò)合理配置轉(zhuǎn)向塊的位置來(lái)減小。上

13、述公式（除ACI以外）均考應(yīng)了前五項(xiàng)的影響.已有的研究指出ACI公式?jīng)]仃考慮非預(yù)應(yīng)力鋼筋的作用而且采用的參數(shù)過(guò)于簡(jiǎn)單，在低含筋率情況卜過(guò)于安全，在高含筋率悄況卜又偏于危險(xiǎn)，R在L/d,=35處，存在弘值突變等問(wèn)題。從表？分析結(jié)果來(lái)GACI公式的計(jì)算統(tǒng)汁結(jié)果偏小、離散性較大且其在低含筋率悄況卜偏保守的看法得到了驗(yàn)證。Chakrabarti在1995年修正了ACI公式，在公式中加入了普通受拉鋼筋的形響因素.公式的計(jì)算結(jié)果比ACI的結(jié)果要好但也存在著計(jì)算值較小且離散性較大的缺點(diǎn)。通過(guò)表2均值和方差的對(duì)比結(jié)果來(lái)石harajli公式的計(jì)算值偏高，這仃AmentJ的論文旳中結(jié)論致.英國(guó)規(guī)范BS8110的公

14、式是將非預(yù)應(yīng)力鋼筋等效為預(yù)應(yīng)力鋼筋，但其計(jì)算結(jié)果并不理想。我IN無(wú)枯結(jié)預(yù)血力規(guī)范的公式限制在綜合配筋指標(biāo)小F0.45的悄況卜，繪主耍是用于樓板結(jié)構(gòu)。通過(guò)試驗(yàn)梁的計(jì)算分析發(fā)現(xiàn)其計(jì)算結(jié)果的離散性也較大，因此也存在一定的缺陷。統(tǒng)計(jì)分析結(jié)果表明.AASHTO-04公式、哈工大基于塾性理論并考慮二汝皿的計(jì)算公式、AASHTO-04修正公式及同濟(jì)大學(xué)基/試驗(yàn)研究的統(tǒng)計(jì)公式的計(jì)辣結(jié)果均號(hào)實(shí)驗(yàn)結(jié)果吻合良好,K計(jì)算值勺試驗(yàn)值Z比的T均值均亍均在間。其中以哈大公式的計(jì)算耕度最高片=095其離散條ft為q-0.04,但由于其計(jì)算方法比較復(fù)雜且僅適川十簡(jiǎn)支梁橋，不便J采用.同濟(jì)公式是以截面性質(zhì)和配筋指標(biāo)建立的回歸公式

15、，從分析結(jié)果來(lái)看比值的平均值為f-0.88,但離散系數(shù)ct=0.05,相對(duì)大一些。雖然AASHTO-04和其修正公式的形式略何不同,但其計(jì)算精度相差不多,比值的平均值分別為x=0.8S和0.85具離散系敵為c,=0.02和0.01綜合考電汁算粘度.簡(jiǎn)捷適用且能夠用F連續(xù)結(jié)構(gòu)計(jì)算.還可更好地適用F不同種類的體外預(yù)應(yīng)力鋼材。AASHTO-04現(xiàn)范的修正公式中采用的是混凝土岡柱體強(qiáng)度，考電到與我川15x15x15(cm3)立方體強(qiáng)度在形狀和尺寸上的差異，須將其換算為我國(guó)宜方體抗壓強(qiáng)度標(biāo)準(zhǔn)值皿、或軸心抗斥強(qiáng)度的標(biāo)準(zhǔn)值齊經(jīng)換算得到原公式中的0.85»0.75”“=1.124幾,取用0.85/&g