【正文】 ive than increase in the size of bars. Numerous small bars, closely spaced, are thus the best solution. Additional mildsteel stirrups may also be required at holddown points to resist the shear. This is also true wherever posttensioned tendons make sharp bends. Practical consideration of concretion dictates the spacing of tendons and ducts. The general rules are that the clear spacing small be oneandonehalf times the maximum size of coarse aggregate. In the overall section, provision must be made for the vibrator stinger. Thus prestressing tendons must either be spaced apart in the horizontal plane, or, in special cases, bundled. In the vertical plane close contact between tendons is quite mon. With posttensioned ducts, however, in intimate vertical contact, careful consideration has to be given to prevent one tendon form squeezing into the adjacent duct during stressing. This depends on the size of duct and the material used for the duct. A fullscale layout of this critical cross section should be made. Usually, the best solution is to increase the thickness ( and transverse strength ) of the duct, so that it will span between the supporting shoulders of concrete. As a last rest\ort it may be necessary to stress and grout one duct before stressing the adjacent one. This is timeconsuming and runs the risks of grout blockage due to leaks from one duct to the other. Therefore the author remends the use of heavier duct material, or else the respacing of the ducts. The latter, of course, may increase the prestressing force required. 中文翻譯： 預(yù)應(yīng)力混凝土建筑 預(yù)應(yīng)力混凝土已經(jīng)廣泛并成功地用于各種類型的建筑。更重要的是，它為建筑師提供了一種變化的自由，以及在各種服務(wù)條件下的行為控制能力。 第三，施工工程師應(yīng)該在結(jié)構(gòu)完工之前，注重鋼筋的臨時(shí)應(yīng)力、松弛應(yīng) 力、截取、加工和安裝階段的應(yīng)力，以及臨時(shí)條件，如復(fù)合灌注時(shí)所需的支柱支撐。 參照施工圖，施工工程師必須按照最實(shí)際和最經(jīng)濟(jì)的要求，盡力將設(shè)計(jì)進(jìn)行細(xì)節(jié)化處理，這樣全部構(gòu)件或結(jié)構(gòu)就能和設(shè)計(jì)需求保持一致。采用梁或者較小的肋（有時(shí)采用較重的金屬網(wǎng)），且梁要盡可能的靠近端部，將有助于控制并分散集中力。 在垂直平面內(nèi)鋼筋的密集接觸實(shí)際其常見的。