1、第六章受拉構(gòu)件承載力計(jì)算【學(xué)習(xí)重點(diǎn)】軸心受拉構(gòu)件承載力計(jì)算；偏心受拉構(gòu)件承載力計(jì)算。【學(xué)習(xí)目標(biāo)】了解受拉構(gòu)件的種類；熟悉軸心受拉構(gòu)件計(jì)算的適用范圍；掌握受拉構(gòu)件承載力的計(jì)算方法；熟悉偏心受壓構(gòu)件的構(gòu)造要求及計(jì)算適用范圍；掌握偏心受拉構(gòu)件承載力的計(jì)算方法。鋼筋混凝土受拉構(gòu)件按縱向拉力作用位置的不同分為軸心受拉和偏心受拉兩種類型。當(dāng)縱向拉力<math display='block'> <semantics> <mi>N</mi> <annotation encoding='MathType-MTEF'>Ma

2、thTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabau

3、aakeaacaWGobaaaa3FF0</annotation> </semantics></math>作用在截面形心時(shí)，稱為軸心受拉構(gòu)件，如鋼筋混凝土屋架下弦桿、高壓圓形水管及圓形水池等。當(dāng)縱向拉力<math display='block'> <semantics> <mi>N</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gz

4、LbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobaaaa3FF0</annotation> </seman

5、tics></math>作用在偏離截面形心時(shí)，或截面上既作用有縱向拉力<math display='block'> <semantics> <mi>N</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rN

6、CHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobaaaa3FF0</annotation> </semantics></math>，又作用有彎矩<math display='block'> <semant

7、ics> <mi>M</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm

8、0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGnbaaaa3FEF</annotation> </semantics></math>的構(gòu)件，稱為偏心受拉構(gòu)件，如鋼筋混凝土矩形水池、工業(yè)廠房中雙肢柱的肢桿等。第一節(jié)軸心受拉構(gòu)件承載力計(jì)算一、軸心受拉構(gòu)件的受力特點(diǎn)承受節(jié)點(diǎn)荷載的桁架或屋架的受拉弦桿和腹桿、剛架和拱的拉桿、受內(nèi)壓力作用的圓形儲(chǔ)液池的環(huán)向池壁、承受內(nèi)壓力作用的環(huán)形截面管道的管壁等通常按軸心受拉構(gòu)件計(jì)算。鋼筋混凝

9、土軸心受拉構(gòu)件，開裂以前混凝土與鋼筋共同負(fù)擔(dān)拉力；開裂以后，開裂截面混凝土退出工作，全部拉力由鋼筋承受。當(dāng)鋼筋應(yīng)力達(dá)到其抗拉強(qiáng)度，截面到達(dá)受拉承載力極限狀態(tài)。二、軸心受拉構(gòu)件承載力計(jì)算根據(jù)承載力極限狀態(tài)設(shè)計(jì)法的基本原則及力的平衡條件，軸心受拉構(gòu)件正截面承載力計(jì)算公式為： <math display='block'> <semantics> <mi>N</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCv

10、AUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobaaaa3FF0</annotati

11、on> </semantics></math><math display='block'> <semantics> <mrow> <msub> <mi>N</mi> <mi>u</mi> </msub> <mo>=</mo><msub> <mi>f</mi> <mi>y</mi> </msub> <msub> <mi>A&l

12、t;/mi> <mi>s</mi> </msub> <mo>+</mo><msub> <mi>f</mi> <mrow> <mi>p</mi><mi>y</mi> </mrow> </msub> <msub> <mi>A</mi> <mi>p</mi> </msub> </mrow> <annotation encodin

13、g='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9a

14、dbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobWaaSbaaSqaaiaadwhaaeqaaOGaeyypa0JaamOzamaaBaaaleaacaWG5baabeaakiaadgeadaWgaaWcbaGaam4CaaqabaGccqGHRaWkcaWGMbWaaSbaaSqaaiaadchacaWG5baabeaakiaadgeadaWgaaWcbaGaamiCaaqabaaaaa4C16</annotation> </semantics></math> （6-1）式中<math display='

15、block'> <semantics> <mi>N</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqq

16、rFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobaaaa3FF0</annotation> </semantics></math>軸向拉力設(shè)計(jì)值；<math display='block'> <semantics> <mrow> <msub> <mi>N</mi> <mi&g

17、t;u</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq

18、=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobWaaSbaaSqaaiaadwhaaeqaaaaa4116</annotation> </semantics></math>軸心受拉構(gòu)件正截面承載力設(shè)計(jì)值；<math display='block'> <semantics> <mrow> <msub> <mi>f<

19、;/mi> <mi>y</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F

20、4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGMbWaaSbaaSqaaiaadMhaaeqaaaaa4132</annotation> </semantics></math>鋼筋抗拉強(qiáng)度設(shè)計(jì)值，<math display='block'> <semantics> <mrow> <msub> <

21、;mi>f</mi> <mi>y</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqr

22、pepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGMbWaaSbaaSqaaiaadMhaaeqaaaaa4132</annotation> </semantics></math>大于300Nmm2時(shí)，按300Nmm2取值；<math display='block'> <semantics> <mr

23、ow> <msub> <mi>f</mi> <mrow> <mi>p</mi><mi>y</mi> </mrow> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYL

24、wzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGMbWaaSbaaSqaaiaadchacaWG5baabeaaaaa4227</annotation> </semantics></math>預(yù)應(yīng)力鋼

25、筋的抗拉強(qiáng)度設(shè)計(jì)值；<math display='block'> <semantics> <mrow> <msub> <mi>A</mi> <mi>s</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMB

26、aeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGbbWaaSbaaSqaaiaadohaaeqaaaaa4107</annotation> </semantics>&l

27、t;/math>截面上全部縱向受拉鋼筋的截面面積；<math display='block'> <semantics> <mrow> <msub> <mi>A</mi> <mi>p</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuL

28、wBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGbbWaaSbaaSqaaiaadchaaeqaaaaa4104</annotation> &l

29、t;/semantics></math>截面上預(yù)應(yīng)力鋼筋的全部截面面積。由式（6-1）可知，軸心受拉構(gòu)件正截面承載力只與縱向受拉鋼筋有關(guān)，與構(gòu)件的截面尺寸及混凝土的強(qiáng)度等級(jí)無關(guān)。三、軸心受拉構(gòu)件構(gòu)造要求（一）縱向受力鋼筋軸心受拉構(gòu)件的受力鋼筋不得采用綁扎搭接；搭接而不加焊的受拉鋼筋接頭僅僅允許在圓形池壁或管中，其接頭位置應(yīng)錯(cuò)開，搭接長度應(yīng)滿足規(guī)范要求。為避免配筋過少引起的脆性破壞，按構(gòu)件截面面積計(jì)算的全部受力鋼筋的直徑不宜小于12mm，構(gòu)件一側(cè)受拉鋼筋的最小配筋百分率不應(yīng)小于0.2%和（45<math display='block'> <se

30、mantics> <mrow> <msub> <mi>f</mi> <mi>t</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBb

31、XgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGMbWaaSbaaSqaaiaadshaaeqaaaaa412D</annotation> </semantics></math>/<math display='block'> <

32、semantics> <mrow> <msub> <mi>f</mi> <mi>y</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLM

33、BbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGMbWaaSbaaSqaaiaadMhaaeqaaaaa4132</annotation> </semantics></math>）%的較大值，也不宜大于5%。受力鋼筋沿截面周邊均勻?qū)ΨQ布置，凈間距不應(yīng)小于50

34、mm，且不宜大于300mm。（二）箍筋在軸心受拉構(gòu)件中，與縱向鋼筋垂直放置的箍筋主要是與縱向鋼筋形成骨架，固定縱向鋼筋在截面中的位置，從受力角度而言并無要求。箍筋直徑不應(yīng)小于縱筋直徑的1/4，且不應(yīng)小于6mm，間距一般不應(yīng)大于400mm及構(gòu)件截面短邊尺寸。【例6-1】已知某鋼筋混凝土屋架下弦，截面尺寸<math display='block'> <semantics> <mi>b</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaa

35、guart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGIbaaaa40

36、04</annotation> </semantics></math>×<math display='block'> <semantics> <mi>h</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbIt

37、LDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGObaaaa400A</annotation> </semantics></math>200mm×150mm，其所受的軸向拉力設(shè)計(jì)值為300kN，鋼筋為H

38、RB335級(jí)，混凝土強(qiáng)度等級(jí)為C30，求縱向受拉鋼筋截面面積<math display='block'> <semantics> <mrow> <msub> <mi>A</mi> <mi>s</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2Caerb

39、uLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGbbWaaSbaaSqaaiaadohaaeqaaaaa4107</annotation>

40、</semantics></math>并選配鋼筋。 【解】由題意知此屋架下弦為軸心受拉構(gòu)件，鋼筋HRB335，<math display='block'> <semantics> <mrow> <msub> <mi>f</mi> <mi>y</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1e

41、v2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGMbWaaSbaaSqaaia

42、adMhaaeqaaaaa4132</annotation> </semantics></math>300Nmm2，C30混凝土，<math display='block'> <semantics> <mrow> <msub> <mi>f</mi> <mi>t</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTE

43、F55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaW

44、GMbWaaSbaaSqaaiaadshaaeqaaaaa412D</annotation> </semantics></math>1.43Nmm2，令<math display='block'> <semantics> <mi>N</mi> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DG

45、i1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobaaaa3FF0</annotation> </semantics></math><

46、math display='block'> <semantics> <mrow> <msub> <mi>N</mi> <mi>u</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBae

47、rbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGobWaaSbaaSqaaiaadwhaaeqaaaaa4116</annotation> </semantics></math>，代入

48、式（6-1），得<math display='block'> <semantics> <mrow> <msub> <mi>A</mi> <mi>s</mi> </msub> <mo>=</mo><mfrac> <mi>N</mi> <mrow> <msub> <mi>f</mi> <mi>y</mi> </msub> </m

49、row> </mfrac> <mo>=</mo><mfrac> <mrow> <mn>300000</mn> </mrow> <mrow> <mn>300</mn> </mrow> </mfrac> <mo>=</mo><mn>1000</mn><mi>m</mi><msup> <mi>m</mi> <mn>2<

50、;/mn> </msup> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vq

51、aqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGbbWaaSbaaSqaaiaadohaaeqaaOGaeyypa0ZaaSaaaeaacaWGobaabaGaamOzamaaBaaaleaacaWG5baabeaaaaGccqGH9aqpdaWcaaqaaiaaiodacaaIWaGaaGimaiaaicdacaaIWaGaaGimaaqaaiaaiodacaaIWaGaaGimaaaacqGH9aqpcaaIXaGaaGimaiaaicda

52、caaIWaGaamyBaiaad2gadaahaaWcbeqaaiaaikdaaaaaaa537B</annotation> </semantics></math> 縱向受拉鋼筋的配筋率為：<math display='block'> <semantics> <mrow> <mi>&#x03C1;</mi><mo>=</mo><mfrac> <mrow> <msub> <mi>A</mi>

53、<mi>s</mi> </msub> </mrow> <mi>A</mi> </mfrac> <mo>=</mo><mfrac> <mrow> <mn>1000</mn> </mrow> <mrow> <mn>200</mn><mo>&#x00D7;</mo><mn>150</mn> </mrow> </mfrac>

54、; <mo>=</mo><mn>3.3</mn><mi>&#x0025;</mi> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2Ca

55、eHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacqaHbpGCcqGH9aqpdaWcaaqaaiaadgeadaWgaaWcbaGaam4CaaqabaaakeaacaWGbbaaaiabg2da9maalaaabaGaaGymaiaaicdacaaIWaGaaGimaaqaaiaaikdacaaIWaGaaGimaiabgEna0

56、kaaigdacaaI1aGaaGimaaaacqGH9aqpcaaIZaGaaiOlaiaaiodacaGGLaaaaa5302</annotation> </semantics></math><math display='block'> <semantics> <mrow> <msub> <mi>&#x03C1;</mi> <mrow> <mi>min</mi> </mrow> </msub> <

57、;mo>=</mo><mn>0.9</mn><mo>&#x00D7;</mo><mfrac> <mrow> <msub> <mi>f</mi> <mi>t</mi> </msub> </mrow> <mrow> <msub> <mi>f</mi> <mi>y</mi> </msub> </mrow> </mfrac

58、> <mo>=</mo><mn>0.9</mn><mo>&#x00D7;</mo><mfrac> <mrow> <mn>1.43</mn> </mrow> <mrow> <mn>300</mn> </mrow> </mfrac> <mo>=</mo><mn>0.429</mn><mi>&#x0025;</mi>

59、</mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=y

60、qaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacqaHbpGCdaWgaaWcbaGaciyBaiaacMgacaGGUbaabeaakiabg2da9iaaicdacaGGUaGaaGyoaiabgEna0oaalaaabaGaamOzamaaBaaaleaacaWG0baabeaaaOqaaiaadAgadaWgaaWcbaGaamyEaaqabaaaaOGaeyypa0JaaGimaiaac6cacaaI5aGaey41aq7aaSaaaeaacaaIXaGaaiOlaiaaisdacaa

61、IZaaabaGaaG4maiaaicdacaaIWaaaaiabg2da9iaaicdacaGGUaGaaGinaiaaikdacaaI5aGaaiyjaaaa5D47</annotation> </semantics></math> 因?yàn)?lt;math display='block'> <semantics> <mrow> <msub> <mi>&#x03C1;</mi> <mrow> <mi>min</mi> </mro

62、w> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyNv2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqp

63、epm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacqaHbpGCdaWgaaWcbaGaciyBaiaacMgacaGGUbaabeaaaaa43DB</annotation> </semantics></math>0.4290.4，所以上式中最小配筋率取0.429。所以配筋率滿足要求，縱向受拉鋼筋選用418鋼筋，<math display='block'> <semantics>

64、<mrow> <msub> <mi>A</mi> <mi>s</mi> </msub> </mrow> <annotation encoding='MathType-MTEF'>MathTypeMTEF55+=feaaguart1ev2aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLnhiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr4rNCHbWexLMBbXgBd9gzLbvyN

65、v2CaeHbl7mZLdGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq=Jc9vqaqpepm0xbba9pwe9Q8fs0=yqaqpepae9pg0FirpepeKkFr0xfr=xfr=xb9adbaqaaeGaciGaaiaabeqaamaabaabauaakeaacaWGbbWaaSbaaSqaaiaadohaaeqaaaaa4107</annotation> </semantics></math>1017mm2。第二節(jié)偏心受拉構(gòu)件承載力計(jì)算矩形水池的池壁、工業(yè)廠房雙肢柱的受拉肢桿、矩形剖面料倉的倉壁或煤斗的壁板、受地震作用的框架邊柱、承受節(jié)間豎向荷載的懸臂式桁架拉桿及一般屋架承擔(dān)節(jié)間荷載的下弦拉桿等均可按偏心受拉計(jì)算。一、偏心受拉構(gòu)件構(gòu)造要求偏心受拉構(gòu)件常用矩形截面形式，且矩形截面的長邊宜和彎矩作用平面平行，也可采用形或工字形截面。小偏心受拉構(gòu)件破壞時(shí)拉力全部由鋼筋承受，在滿足構(gòu)造要求的前提下，以采用較小的截面尺寸為宜，大偏心受拉構(gòu)件的受力特點(diǎn)類似于受彎構(gòu)件，宜采用較大的截面尺寸，有利于抗彎和抗剪。矩形截面偏心受拉構(gòu)件的縱向鋼筋應(yīng)沿短邊布置。小偏心受拉構(gòu)件的受力鋼筋不得采用綁扎搭接接頭。矩形截面偏心受拉構(gòu)件縱向鋼筋配筋率應(yīng)滿足其最小配