電大《混凝土結(jié)構(gòu)設(shè)計(jì)原理》期末復(fù)習(xí)考試重點(diǎn)資料小抄-預(yù)覽頁
【正文】 力增大，也可能使截面不對稱，從而降低構(gòu)件的承載力。 (3)少筋梁破壞；混凝土一開裂，鋼筋馬上屈服而破壞，屬脆性破壞。 4．影響無腹筋簡支梁斜截面受 剪承載力的主要因素有哪些 ?答：影響元腹筋簡支梁斜截面受剪承載力的主要因素有：剪跨比、混凝土強(qiáng)度和縱筋配筋率。由于砌筑用的百材、預(yù)制塊及混凝土等材料的共同特點(diǎn)是抗壓強(qiáng)度高而抗拉、抗彎、抗剪強(qiáng)度低，在結(jié) 構(gòu)工程中常作為以承壓為主的結(jié)構(gòu)構(gòu)件。 3．鋼筋混凝土受壓柱中為何不應(yīng)采用過大的配筋率 ?答：若一定的荷載長期持續(xù)的作用，由于混凝土的徐變特性，其塑性變 形更加顯著，以致混凝土應(yīng)力逐漸減小，而鋼筋應(yīng)力逐漸增大。 4．什么是先張法 ?在先張法構(gòu)件配筋上有什么特點(diǎn) ?答：先張法，即先將預(yù)應(yīng)力鋼筋張拉并錨固在張力臺(tái)座上，后澆筑構(gòu)件混凝土，待混凝土達(dá)到足夠的強(qiáng)度后再放張，以此實(shí)現(xiàn)預(yù)應(yīng)力的方法。 1．根據(jù)梁受彎破壞形式的不同，梁的破壞可分為哪三類 ?各有何破壞特點(diǎn) ?答：根 據(jù)梁受彎破壞形式不同，梁的破壞可分為：適筋梁、超筋梁和少筋梁三類。 超筋梁的破壞特點(diǎn)是：破壞始自受壓區(qū)混凝土的壓碎。 少筋梁的破壞特點(diǎn)是：受拉區(qū)混凝土一旦開裂，受拉鋼筋就達(dá)到屈服，并迅速經(jīng)歷整個(gè)流幅而進(jìn)入強(qiáng)化工作階段。 剪壓破壞特征：梁破壞時(shí)，與斜裂縫相交的腹筋達(dá)到屈服強(qiáng)度，同時(shí)剪壓區(qū)的混凝土在壓應(yīng)力和剪應(yīng)力的共同作用下，達(dá)到了復(fù)合受力時(shí)的極限強(qiáng)度。這三種形態(tài)，在設(shè)計(jì)中都應(yīng)避免。當(dāng)采用高等強(qiáng)度鋼筋時(shí)，一般是混凝土先被壓碎而鋼筋尚未達(dá)到屈服強(qiáng)度。可作為受彎構(gòu)件開裂彎矩的計(jì)算依據(jù)；第 Ⅱ 階段 —— 帶裂縫工作階段，相當(dāng)于梁使用時(shí)的應(yīng)力狀態(tài)，可作為正常使用階段的變形和裂縫寬度計(jì)算的依 據(jù)；第 Ⅲ 階段 —— 破壞階段末可作為承載能力極限狀態(tài)計(jì)算時(shí)的依據(jù)。 (4)配箍率和箍筋強(qiáng)度：配箍率塒。 ． 4．何謂軸心受壓構(gòu)件 ?鋼筋混凝土軸心受壓構(gòu)件按配筋方式不同可分為哪兩種形式 ?答：當(dāng)荷載的合力通過構(gòu)件截面重心的受壓構(gòu)件即為軸心受壓構(gòu)件。 (2)混凝土強(qiáng)度 R：梁的抗剪承載力隨混凝土強(qiáng)度提高而提高。 2．什么叫換算截面法 ? 為了便于應(yīng)用材料力學(xué)中勻質(zhì)梁的公式，在鋼筋混凝土結(jié)構(gòu)計(jì)算中，把由鋼筋和混凝土兩種彈性模量不同的材料組成的實(shí)際截面，換算成由一種拉壓性能相同的假想材料組成的與 它功能相等的勻質(zhì)截面，此即所謂換算截面。 請刪除 O(∩ _∩ )O 謝謝： Foreigners flock to China39。s 39。s porcelain capital, where fine ceramics have been produced for more than 1,700 years, attracting numerous porcelain pilgrims from across the globe. Unlike huge Chinese metropolises such as Beijing and Shanghai, Jingdezhen is a prefecturelevel city with no bar streets or international stores that are popular among expatriates. But despite its lack of Western chain stores, Jingdezhen is one of the most international cities in inland China, with ceramic studios owned by foreigners dotting the streets, the surrounding countryside and even remote mountaintops. When she first visited the city in 2021, De La Vega was impressed by the discarded pieces of porcelain she found lying around. I dug out many pieces from the soil around the ceramics works all the old Buddha heads, hands and feet, which I rebuilt into new sculptures and used in my next exhibition in Australia, she said. I love this place because the process of making ceramics is a very peaceful one. Visafree policy brings Chengdu biz, tourism boost. Making national headlines several times, Chengdu39。s ancient indigenous religion, while Du jiang yan is considered to be the oldest functioning watercontrol project in the world. Chengdu ranked third in tourist facilities, management and services among 60 Chinese cities in a customer satisfaction survey released last year. But, Li added that efforts are still needed to develop more tourism products, improve English services and provide accurate translation of traffic signs and scenic billboards. Zhao Yun, chairwoman of British Chamber of Commerce Southwest China, told China Daily that his colleagues found the policy very convenient. A British client once flew here and stayed for just one day to check her ordered goods, she said. Zhao was born in Shanxi province, but she has lived in Chengdu for more than 10 years. My life was like a running race moving from place to place. I also lived in Beijing and Shanghai before, she said. But Chengdu is a place that you never want to leave once settling down. It is now my second hometown, she said. If the environment is further improved, the city will attract more people to visit and live, with the 72hour visafree policy and pelling conditions in transportation, culture, climate and cuisine, he said. Foreigners also gave positive feedback on the policy. A spokesman from Dell Inc said the pany has a global hub of operation in Chengdu, so the threeday visa has an immediate and positive influence on the pany39。an. Lou held a joint interview with 27 media, including China Daily, the first in a series of interviews entitled Chinese Media Along the Silk Road. The interview s w ill be in Shaanxi and Gansu provinces and the Xinjiang Uygur autonomous region, as w ell as Kazakhstan, Uzbekistan and Turkey. The media group held the first interview on Wednesday morning in Xi3
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