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1、重庆科技学院学生毕业设计(论文)外文译文学 院建筑工程学院专业班级土木应08(3)学生姓名学 号译文要求1. 外文翻译必须使用签字笔，手工工整书写，或用A4纸打印。2. 所选的原文不少于10000印刷字符，其内容必须与课题或专业方向紧密相关， 由指导教师提供，并注明详细出处。3. 外文翻译书文本后附原文（或复印件）。外文原文出自：R.帕克、T.波利编著的钢筋混凝土结构中的417-423页7.4有腹筋钢筋混凝土梁的抗剪机理7.4.1腹筋的作用梁内有了像箍筋这样的腹筋之后，不会从根本上改变前面所描述的抗剪机理。作为梁作 用的主要元件的混凝土悬臂这时将像被拉住的悬臂那样工作。除去有骨料咬合、销栓和悬
2、臂 的弯曲作用所联合承担的粘结力AT之外，还有一部分粘结力AT能够由习惯上所说的“桁 架作用”来承担。在这个桁架中，悬臂起斜向压杆的作用（见图7.14）。图7.14起斜压杆作用的混凝土悬臂箍筋的存在在其他许多方面对梁作用也是有益的，它通过以下方式对抗剪机构的强度发 挥作用：1. 改进销栓作用。箍筋能够有效地支承在它附近与弯剪裂缝相交的纵向钢筋。2. 通过桁架作用产生的斜压力Cd抵消悬臂块体内的弯曲拉应力。3. 限制斜裂缝在弹性范围内的张开程度，从而使由骨料咬合作用传递的剪力得以维持 和增强。4. 当箍筋布置得足够密时，能对混凝土提供约束，从而特别是在受拱作用影响的部位 提高其抗压强度。5. 当
3、在锚固区内由于销栓力和锚固力的作用而形成劈裂裂缝时，能防止粘结遭到破 坏。总之，可以说，做了适当的细部设计的腹筋将能保持梁的整体性，并因而能够保持前面 已经详述的梁机构的强度Ve，从而使更多的建立Vs能由桁架机构来承担。7.4.2桁架机构一个平行弦桁架与一个有腹筋混凝土梁之间在抗剪作用方面的相似性是混凝土结构的 一个古老的概念。这种由Morsch7.2.23在本世纪初所假定的相似性的含义是，等效桁架的腹 杆是由起拉杆作用的箍筋和走向平行于斜裂缝的、通常是与梁轴成45角的混凝土压杆所 组成的。混凝土的弯曲受压区和弯曲受拉钢筋构成这种比拟铰接桁架的上弦和下弦。桁架的 内力只需根据平衡条件就能确定。
4、这个桁架的性能与前已详述的“理想梁作用”相似到了如 此地步，以至它能承受分散于弯曲受拉钢筋方向上的各个虚拟铰接点处的粘结力AT，从 而以不变的内力偶臂长来抵抗变化的外弯矩。在梁内伴随着梁作用或拱作用以及桁架机构而出现的变形之间是不协调的。这种按惯例 不予考虑的应变不协调性在趋近极限（即塑形）状态时越来越不显著。图7.15中的比拟桁架描绘了腹筋以B角倾斜于水平线的一般情况。它也可以用来表示 有桁架所承担的外剪力Vs与各内力之间的关系。承受压力的Cs的斜压杆与水平线的交角为a。由图7.15中所绘节点X的平衡力多边形显然可见：K = Q sin 厦=g sin fi(7.18)式中Ts为所有穿过斜裂
5、缝的箍筋内力之和。腹筋在单位梁长内承受的力为Ts/s，其中s为 箍筋间距，其值按比拟桁架的几何关系应为：s = Jd(cotot + cot 0)(7,19)由公式7.18和7.19可得单位长度上箍筋的内力为：玄=h = %(7 20)& jd sin fS (cot oc + cot /f) s式中Av为沿梁长按间距为s布置的腹筋的截面面积，fx为箍筋应力。图7.15比拟桁架中的内力从设计应用来看，像在共事7.15中那样用名义应力来表示建立是比较方便的。总剪力 Vu是假定为一部分由桁架机构来承受(Vs)，另一部分由前面描述的梁机构或拱机构来承受 (Vc)。这一关系如用应力表示即为：% =，+
6、 %(721)式中(7.22)将公式7.20与共事7.22结合起来，则当fs=fy时按理想强度所需的腹筋面积为:G-23)A，Sin 夕(cot oc + cot )6) fv现假定斜压力Cd在桁架压杆中产生均匀应力。压杆的有效高为s =s sin a =jdsin a (ctg a +ctgB)。于是，由桁架机构产生的斜压应力可以近似地表示为：sin2 a (cot ct + cot 7+24)f _ q _匕*虬Xbwjd sin2 at (cot a + cot (I)对于常见的腹筋布置情况，公式7.23和7.24便简化如下:1.垂直箍筋，B=90当斜压杆倾角a =45。时扁如当斜压杆倾
7、角a =30时sb*& = 0.58% -j-扁=231 ps2, 斜置腹筋，B Pollibg IMHRi史 . L_ Improv-jnjtheoi?Lributaon fllw dwidiictLun. A stirrupcao effedively h InnjcikiLnal hai that k heiii effatd h1 出日专冷lfI /枷注e& clce (0 a 阻 irrupi_ Sppr酉in? ilcjtur-al lenAilc stresscs in the hl-ikv 国化昂 呵 E晖佛 erf the digonaE Gornpresiskin Fuhx
8、 Ct rrulting ft oar Emsa action.F用. 1柬 ConcKK canlifeYEraacLRK slculi.SivwK,th sirrf Ekfomwlinn r Mt-mbers ith3. Limiting th*? ujxning of diaonl tracks within ihc hsiic rangu thuscnhand and preservingxbear uansfcrbyimeigk.4. Proviin confinement yhm iIh： slirrups ;ins sulrficicfilly spspsi. thus incr
9、easing the compression srengih of loGililies particul-arty affected by anh action.5. Preventing the breakdnwn of bond when saluting cmcks； develop in anchorage zxrs because of dowel und anchorage Ibrcx:s.Ie may be saM lluu suitably detailed wb reinforcement will preserve the int&THy therefore Ihu 以的
10、染h. of the previously ckhned beam mHihanism .allowing Additional shear forces 旦 io be resiited by iruss mocharism.7.4,2 The I rtBis MechanismThe analogy between the shear rcsisif a paralki chord truss and u wcb-Tuinforccd concrete beam i$ an old conccpC of wncrelc strtnres. The anaJogy. poUikkied by
11、 Morsch at ilve bughmiug of the wni v. 13 impli虐 Ihul (lie web of the cquivalcni iruss consists of xiirrups acting :as tension numbers and conovlvsiriitg running parallel tft diagonal cractj, generally ;il 45 to tbe beam* axis. The flttwral concrete compression zone and the Hextira reinlbrcemvni (or
12、fh rhe 1op and biuiom chords。Chis analogiu$ pinjQMiiUd fuss. The (arctfi in the iracan be dclermificd From cons&dcra- tions of equilibrium only. The behavior of the truss is similar the previously defined * perfect beam ad ion11 to the extent ihat ii can sustain discrete bond forces AT眦 1 he hypothe
13、tical pin joinU along Lhe flexural rcinlbFCe- incnt,. !hu$ 整航能社理 variable external ninments on a constant intcrnaS Icvcr rrh.The ikformaEiGiis associated wiih beam or arch action and ihe cr.uss liuxtianism wthin clu： beam arc not Gomp?iiiblt This strain iiKonipatibilaty. tnuJilionally ignored, bcuon
14、is progressively ? signlfican! 415 ultiiwitc (i.j plastic)顷dilions arc approached.The miiilogoLis inus appearing in Fig. 7.15 depkis llw general ctviae M web ranfarccnrcnt indined at an angle/# to the horizomal It will 就丁、诺 E iliustTWt the rekiiion between the external ihar force % s 阮 resisted by l
15、he tmss Mid ihc various miernal forces. The dwinai compression sirut; Tcsisling a force are inclined at an angk a 1。he horiz.inUil. From the uiiibrium force polygon drawn for joint X in Fig. 7.15 ii is evident lhai-= Cj $in a = Ta sin fl(7-18)where 7； k live resultiint of all slitr叩 forces acrosi th
16、e diagonal! cniek. The web steel fora per unit length of bciim i$ Tg where From lite geometry of lhe analogous trus lhe spuming ltwccn stirrups3 = Jdfeot ot + 81 /J)(7外Sbw ftrdgtntff Ib JIHk日衍心赤 Bemns With Web RelnfofueoMsiF岫.7 JS. InicrnKl fnrH$ in x乌尊仲|地.助八 Iniys.WSFrom Eqs. 718 and 7.19? the s4ir
17、rup force per unii length kP.20)务=_21= %s jd sin * (rota 十 cot /T| awhere .4,. is (he area of the web rcinforcefneiit $网oed 眦 ii dislancc a along 1he b/im und J； Mie sliirrup stress17-21)dr design purposes il is convtiiiern g express shwiT in terms of nominal stresses as in Ec, 75, The Cotai Gtcax I
18、, is aaunwd be 网$渤用 parity by lhe truss mechanism(K)，血 paHly by the previously described beam oj arch mechanreiTis i Ph In terms of stresses tht& i& expreed 才$%=l7 +虬where(7.22)By combining Eqs. 7.20 and 7.21 the required iirwi of *典 reinfoTOnicnl at ideal strength, when 工becomesf7.Z3：l f sb.* = sin
19、 (co-t a- + ccc jj)Tlic diagonal &xnprssion force J is assumed to generate uniform sircsscs in the struts of the truss. The truls an effective d中1 h if jr - s sin a - M sic a (eai a 十 cal 外 Thus thr dUgonat comprMswn Etre&ses due to the tfuss mcchanisjn can be approxintd hy勤.khjd sin11 orfcol x 耳 co
20、t stnJ at (oot a 与 cot 田Stre&fi in4 Dtformiliun af Mmber HhrsrFor I lx： coni mon cas 必 nif web scecl anangcwcni Eqj 7.23 and .24 as follows:L XTRTICAL SJIKRUPS,诉= W1Cp!*wprc-WKVT cliiJQf)版Hs M ot = 45J 凯7.23)17.24)A扣；荔-况Ccjrrtpr4?R?jflrt 4翊owk uc a = 3CT17.2,1b)sf?w4 h 0.5Stx 一产 A旗 S1DP1NG WCU I4.HI
21、NFQRCEM3-NT, 0 网Cumg品nt diagonafs m h = 45(7.2Jcl= 也 业(7.2-fc)1 (sin ” + 印$ 面 fk1 4- oo t jfWeb rertt/nrvcflirJU tinJ .strurs ai 45(?.24djThe slope of?hc cimpTussiot)duigonak hus been traditionally jissuined to be 45 l-o the bwun axis. It h-as tn。始xwcU h-oweven ctifli Rhe slpc of lhe diagcinjl crack
22、s ai the 6thei haiwi the Iruts axe sleeper in che vicinity of poim ki睇d$. However, jn these areas local inch wkrm boosts the capicily nf the Qlhcr shear rarrj3tig nxciianisins, Generally in a beam having. high ecicppK slrhgch and low ub content, reprewnlnig. a less rigid tcnSoi, syseem, the compress
23、ion struts arc at an ansk less than 45V hgs the stirrups mure fleccivc than in 皂 45 irustk Conwcry with large web 故el concentMTSHwr RtMrikiMt 甬 Hirmforcwi CbercBr Rm ms With Wcfc RiWnrcrmcntiiJid lowtr cuiircte 求心gih. the load on the concrete will be relieved at he cstpvuse of larger $drrup partkipa
24、iion. * The slopes o( 1 he diagonoil tracks in the vicinity of poih! IcXids and a puuiI of conlraflekurc! are displayed m Fg 7.16.Fist diagonal compressjijji struts and am叩 irrups imply kirper coitcreic crnpTCSsion siresscx (tf. Eqs. 7.244 and 7.24bl This indicates【hai ihc web stctl content cimnot 阮
25、 i ntreased rndelaniidy. Figure 7J (i jUhjws a continuous! 晌iib*ebbed flanged beam wiih heavy web reinfortcmcnL fn sudk beanie shear failure may be brought about by web criishirijj ;jtused by diagonF 4；ciniprcsston (Eq. 7.24). Whcti assessing the ciimprcssion ；ilrenglh of the web orbims. it is neces
26、siiR to consider foHowing addilioiml (actars:L Thi：$am action see Fig, 7.7). SecondjiTy moment at e incrod need bccaossi f ?be ubricnoi：疽tnw pin joiius rn ihc truss.2. Sdrrufw px!irng through iransmit lensjon to ihec struts hy of bond, ah lhat generally a biaxial staEe cf stniins prevails. The compr
27、ession Ciflpmpicsion fortes tire introdDcl 浏 the joims of ihc anaogau&1m电：.md theseire far from btsing evenly dthiribuld across the vteh,EkxxnLrici1ie$ and iranersai ensile stresses ma y 枳！ present.4. Some diagonals way be incHiwd ；M an angle cciiisidtraWy smaller H；hr45 to the kunzoiitttL ：usd ibis
28、 wtlJ result inincrease in diagonalcompression str件s (see Eq. L24 und Fig. 7.L6J.Tbcic ohservatkins poim lu the need to liinii diagonal concrui t； stresses 6 a value wdf below the crushing sifength of the cancrle. I or this reason 血 AC! limns ihc contribution of (he Iruss i)wlimujn nomi商I shear stre
29、ss in a beiim |ih psi units) is .10、？/； attained in beams of reciEiguhr cross section,Stirrups can develop theix assigned slrctiglh onfy if they are sdeqvuLdy anchored. A slirrup may he crossed by a diflonal crack 刎 my point along i康 length. Since rhe cnick may he very close to tension or i?cmpTHlR*FuXURE2WShnr RfMhian-r id RlWcinM CiMCicit Bcms Wlfli 梆讪 Reinforwmcntover (h-c full wxWnt vf iLn kicigih. Thcieforc it is importanl tN
