電視廣播大學(xué)電大《鋼筋混凝土結(jié)構(gòu)設(shè)計(jì)與砌體結(jié)構(gòu)》期末必備考試小抄【終極排版直接打印】

1、電大鋼筋混凝土結(jié)構(gòu)設(shè)計(jì)與砌體結(jié)構(gòu)考試小抄1預(yù)應(yīng)力砼構(gòu)件的主要優(yōu)點(diǎn)有哪些？答：提高了構(gòu)建的抗裂能力；增大了構(gòu)件的剛度；充分利用高強(qiáng)度材料；擴(kuò)大了構(gòu)件的應(yīng)用范圍。2張拉控制應(yīng)力如何確定？為什么先張法的控制應(yīng)力略高于后張法?答：指張拉預(yù)應(yīng)力鋼筋時(shí)，張拉設(shè)備的測(cè)力儀表所指示的總張拉力除以預(yù)應(yīng)力鋼筋截面面積得出的拉應(yīng)力值；由于先張法中鋼筋分批張拉以及預(yù)應(yīng)力鋼筋與張拉臺(tái)座之間的溫差等因素產(chǎn)生的預(yù)應(yīng)力損失，是張拉控制應(yīng)力值提高。3 預(yù)應(yīng)力損失由哪些？減少各項(xiàng)損失的措施是什么？不同張拉方式損失是如何組合的？先張法、后張法的第一批、第二批預(yù)應(yīng)力損失分別是什么？答：張拉端錨具變形和鋼筋內(nèi)縮引起的預(yù)應(yīng)力損失l1;減

2、少墊片，采用變形小的錨具，后張法采用兩端張拉預(yù)應(yīng)力鋼筋與孔管壁之間的摩擦力引起的預(yù)應(yīng)力損失l2;超張拉，兩端張拉混凝土加熱養(yǎng)護(hù)時(shí)，受張拉的鋼筋與承受拉力的設(shè)備之間的溫差引起的預(yù)應(yīng)力損失l3;采用兩階段升溫養(yǎng)護(hù)方法；預(yù)應(yīng)力鋼筋的應(yīng)力松弛引起的預(yù)應(yīng)力損失l4;超張拉混凝土收縮和徐變引起的預(yù)應(yīng)力損失l5；采用高標(biāo)號(hào)水泥，減少水泥用量，采用級(jí)配好的骨料，加強(qiáng)振搗，提高混凝土的密實(shí)性，加強(qiáng)養(yǎng)護(hù)，減少混凝土收縮，采用高效減水劑減少水灰比，控制混凝土應(yīng)力，防止發(fā)生非線(xiàn)性徐變用螺旋式預(yù)應(yīng)力鋼筋作配筋的環(huán)形構(gòu)件，由于混凝土的局部擠壓引起的預(yù)應(yīng)力損失l6;直徑d越大損失越小，d較大時(shí)，l6忽略不計(jì)。 先張法構(gòu)件第

3、一批預(yù)應(yīng)力損失：l1+l2+l3+l4;后張法構(gòu)件第一批預(yù)應(yīng)力損失：l1+l2;先張法構(gòu)件第二批預(yù)應(yīng)力損失：l5；后張法構(gòu)件第二批預(yù)應(yīng)力損失：l4+l5+l64張拉控制應(yīng)力為什么不能過(guò)大也不能過(guò)??？答：（1）太小就起不了提高有效應(yīng)力的作用；（2）con過(guò)大會(huì)：個(gè)別鋼筋可能被拉斷施工階段可能會(huì)引起構(gòu)件某些部位受拉甚至開(kāi)裂，還可能使后張法構(gòu)件端部混凝土產(chǎn)生局部受壓破壞 使開(kāi)裂荷載和破壞荷載相近，一旦出現(xiàn)裂縫，將很快破壞，即產(chǎn)生無(wú)預(yù)兆性的脆性破壞 增大預(yù)應(yīng)力鋼筋的松弛損失。5單層廠(chǎng)房結(jié)構(gòu)作用荷載有哪些？各種荷載的傳遞路徑是怎樣的？答：恒載包括各種構(gòu)件、維護(hù)結(jié)構(gòu)及固定設(shè)備的自重;活載包括屋面活載、雪荷

4、載、積灰荷載、風(fēng)荷載、吊車(chē)荷載等。橫、豎向荷載主要通過(guò)橫向平面排架傳至地基?？v向荷載通過(guò)縱向平面排架傳至地基。6柱間支撐作用：承受由抗風(fēng)柱和屋蓋橫向水平支撐傳來(lái)的山墻風(fēng)載，由屋蓋結(jié)構(gòu)傳來(lái)的縱向水平地震作用及由吊車(chē)梁傳來(lái)的吊車(chē)縱向水平制動(dòng)力，并將它們傳給基礎(chǔ)。柱間支撐作用是承受由抗風(fēng)柱和屋蓋橫向水平支撐傳來(lái)的山墻風(fēng)載，由屋蓋結(jié)構(gòu)傳來(lái)的的縱向水平地震作用及由吊車(chē)梁傳來(lái)的吊車(chē)縱向水平制動(dòng)力，并將它們傳給基礎(chǔ)，還能提高廠(chǎng)房的縱向剛度。7在確定計(jì)算簡(jiǎn)圖時(shí)作了哪些假設(shè)？如何提取排架的計(jì)算簡(jiǎn)圖？答：做如下假定1柱下端嵌固于基礎(chǔ)中，固定端位于基礎(chǔ)頂面。2柱頂與屋架或屋面梁為鉸接，只能傳遞豎向軸力和水平剪力，不

5、能傳遞彎矩。3橫梁為軸向剛度很大的剛性連桿。在假定基礎(chǔ)上得到橫向排架的計(jì)算模型，在該計(jì)算模型基礎(chǔ)上加以荷載就成為排架結(jié)構(gòu)的計(jì)算簡(jiǎn)圖。8牛腿的破壞形態(tài)有哪些？答：彎壓破壞；斜壓破壞；剪切破壞；此外還有因加載板過(guò)小而導(dǎo)致加載板下混凝土局部壓碎破壞，因縱向受拉鋼筋錨固不良而拔出等破壞。 9柱下獨(dú)立基礎(chǔ)的設(shè)計(jì)內(nèi)容有哪些？這些內(nèi)容滿(mǎn)足后能防止哪些破壞？基礎(chǔ)高度應(yīng)滿(mǎn)足哪兩個(gè)要求？答：內(nèi)容有:確定基礎(chǔ)底面尺寸和基礎(chǔ)高度；計(jì)算基礎(chǔ)底板配筋并采用必要的構(gòu)造措施等。能夠防止柱周邊或變階處的截面產(chǎn)生沖切破壞。防止在基礎(chǔ)底板基凈反力作用下，因兩個(gè)方向均產(chǎn)生向上的彎曲而破壞。10什么是剛性基礎(chǔ)？什么是柔性基礎(chǔ)？答：剛性

6、基礎(chǔ)是指用磚、石、灰土、混凝土等抗壓強(qiáng)度大而抗彎、抗剪強(qiáng)度小的材料做的基礎(chǔ)（受剛性角的限制）；柔性基礎(chǔ)是指用抗拉、抗彎、抗壓、抗剪均較好的鋼筋混凝土材料做的基礎(chǔ)。11框架結(jié)構(gòu)的布置方法有幾種？各種結(jié)構(gòu)布置方法有什么優(yōu)缺點(diǎn)？答：框架結(jié)構(gòu)有橫向承重布置（優(yōu)點(diǎn)：可以在一定程度上改善房屋橫向與縱向剛度相差較大的缺點(diǎn)，其聯(lián)系梁的截面高度一般比主梁小，窗戶(hù)尺寸可以設(shè)計(jì)得大些，室內(nèi)采光好，通風(fēng)好）、縱向承重布置（優(yōu)點(diǎn);便于管線(xiàn)沿縱向穿行，當(dāng)?shù)鼗胤课菘v向不夠均勻時(shí)，縱向框架可在一定程度上調(diào)整這種不均勻性；缺點(diǎn)：房屋的橫向抗側(cè)移剛度?。╇p向承重布置（整體性受力好性能好，特別適合對(duì)房屋結(jié)構(gòu)的整體性要求較高和樓面

7、荷載較大的情況下采用）12如何選取承重框架的計(jì)算單元?答：跨度：跨左右兩邊柱截面形心軸之間的距離；層高：底層柱高從基礎(chǔ)頂面算至柱頂標(biāo)高處；中間標(biāo)高：從下一層樓面標(biāo)高算至層面標(biāo)高；頂層標(biāo)高：從頂層樓面標(biāo)高算至層面標(biāo)高13框架在豎直荷載作用下內(nèi)力近似求解有哪些方法？該方法的假設(shè)條件是什么？ 答：分層法基本假定：在豎向荷載作用下，框架側(cè)移小， 因而忽略不計(jì)；每層梁上的荷載對(duì)其他各層梁的影響很小，可以忽略不計(jì)，因此每層梁上的荷載只在該層梁及與該層相連的柱上 分配和傳遞。疊代法：基本假定：不考慮框架側(cè)移；考慮框架側(cè)移時(shí)；系數(shù)法：基本假定：兩個(gè)相鄰跨的跨長(zhǎng)相差不超過(guò)短跨跨長(zhǎng)的20%；活載與恒載之比不大于3

8、； 荷載的均勻布置；框架梁截面為矩形時(shí)14挑梁、過(guò)梁應(yīng)進(jìn)行哪幾個(gè)方面計(jì)算？答：跳梁：抗顛覆計(jì)算；極限承載力計(jì)算；構(gòu)造要求過(guò)梁：極限承載力計(jì)算；構(gòu)造要求15砌體局壓破壞有哪些破壞特征？答：因豎向裂縫的發(fā)展而破壞；劈裂破壞；局部受壓面積附近的砌體壓壞。16影響砌體抗壓強(qiáng)度的主要因素有哪些？答：一、砌體材料的物理、力學(xué)性能：塊體和砂漿的強(qiáng)度; 塊體規(guī)整程度尺寸；砂漿的變形與和易性；二、砌體工程施工質(zhì)量：灰縫砂漿飽滿(mǎn)度；塊體砌筑時(shí)的含水率；灰縫厚度；砌體組砌方法。17砌體受彎破壞形態(tài)及特征是怎樣的？答：分為三種破壞形態(tài):a) 當(dāng)截面內(nèi)的拉應(yīng)力使砌體沿齒縫截面破壞，稱(chēng)為砌體沿齒縫截面彎曲受拉； b) 砌

9、體沿塊體縫面破壞，稱(chēng)為砌體沿塊體截面彎曲受拉；c) 砌體沿通縫截面破壞，稱(chēng)為砌體沿通縫截面彎曲受拉。18在哪些情況下需要考慮砌體抗壓強(qiáng)度設(shè)計(jì)值的調(diào)整系數(shù)？答：有吊車(chē)房屋砌體，跨度不小于9m的梁下燒結(jié)普通磚砌體，跨度不小于7.2m的梁下燒結(jié)多孔磚、蒸壓灰砂磚、蒸壓粉煤灰磚、混凝土和輕骨料混凝土砌塊砌體，a為0.9.對(duì)于無(wú)筋砌體構(gòu)件，其截面面積小于0.3m2時(shí)，a為其截面面積加0.7對(duì)于配筋砌體構(gòu)件，當(dāng)其截面面積小于0.2m2時(shí)，a為其截面面積加0.8當(dāng)砌體用水泥砂漿砌筑時(shí)，隊(duì)表2-4表2-9的數(shù)值，a為0.9.隊(duì)表2-10的數(shù)值，a為0.8；對(duì)于配筋砌體構(gòu)件，當(dāng)其中的砌體采用水泥砂漿砌筑時(shí)，僅對(duì)

10、砌體的強(qiáng)度設(shè)計(jì)值乘以調(diào)整系數(shù)a。當(dāng)施工質(zhì)量控制等級(jí)為c級(jí)時(shí)，a為0.89.當(dāng)驗(yàn)算施工中房屋的構(gòu)件時(shí)，a為1.119墻體布置方案有哪些？各自?xún)?yōu)缺點(diǎn)及應(yīng)用情況？答：橫墻承重（優(yōu)點(diǎn)：橫墻間距小且數(shù)量較多，橫向剛度較大、整體性好、抵抗風(fēng)荷載、地震作用以及調(diào)整地基不均勻沉降的能力較強(qiáng)，結(jié)構(gòu)簡(jiǎn)單以及施工方便，因縱墻不承重致建筑立面易處理以及門(mén)窗的布置和大小較靈活， 缺點(diǎn)：因縱墻較密，建筑平面布置不靈活。應(yīng)用：房間大小固定、橫墻間距較密的住宅、宿舍、旅館以及辦公樓等）；縱墻承重（優(yōu)點(diǎn)：建筑平面靈活，與橫墻承重結(jié)構(gòu)相比，墻體材料用量較少、屋樓蓋構(gòu)件用料較多， 缺點(diǎn)：橫向剛度較差、縱墻上門(mén)窗洞口的布置大小受一定

11、的限制。 應(yīng)用：用于開(kāi)間較大的教學(xué)樓、醫(yī)院、食堂、倉(cāng)庫(kù)）；縱橫墻承重（優(yōu)點(diǎn)：房屋沿縱、橫向剛度均較大且砌體應(yīng)力較均勻，具有較強(qiáng)的抗風(fēng)能力，占地面積相同的條件下，外墻面積較少， 應(yīng)用：多層塔式住宅等）；框架承重（優(yōu)點(diǎn)：內(nèi)部形成大空間，平面布置靈活，易滿(mǎn)足使用要求；與全框架結(jié)構(gòu)相比，可節(jié)約鋼材、水泥。降低房屋造價(jià)， 缺點(diǎn)：因橫墻較少，房屋的空間剛度較差。抵抗地震能力和地基不均勻沉降能力弱，應(yīng)用于商餐廳以及多層工業(yè)廠(chǎng)房等）四種型式。20在砌體結(jié)構(gòu)中設(shè)置圈梁的目的是什么？答：增強(qiáng)房屋的整體剛度；防止地基不均勻沉降或較大振動(dòng)荷載等對(duì)房屋引起的不利影響；提高墻體抗剪、抗彎、承重的能力。1驗(yàn)算柱的受壓承載力

12、： 柱頂截面驗(yàn)算查表得到f=，沿截面長(zhǎng)邊方向按偏心受壓驗(yàn)算：，沿截面短邊方向按軸心受壓驗(yàn)算：同上。2局部受壓承載力驗(yàn)算查表得到砌體抗壓強(qiáng)度設(shè)計(jì)值為f=， ，局部受壓承載力滿(mǎn)足要求。3排架上風(fēng)荷載標(biāo)準(zhǔn)值：1預(yù)應(yīng)力砼構(gòu)件的主要優(yōu)點(diǎn)有哪些？答：提高了構(gòu)建的抗裂能力；增大了構(gòu)件的剛度；充分利用高強(qiáng)度材料；擴(kuò)大了構(gòu)件的應(yīng)用范圍。2張拉控制應(yīng)力如何確定？為什么先張法的控制應(yīng)力略高于后張法?答：指張拉預(yù)應(yīng)力鋼筋時(shí)，張拉設(shè)備的測(cè)力儀表所指示的總張拉力除以預(yù)應(yīng)力鋼筋截面面積得出的拉應(yīng)力值；由于先張法中鋼筋分批張拉以及預(yù)應(yīng)力鋼筋與張拉臺(tái)座之間的溫差等因素產(chǎn)生的預(yù)應(yīng)力損失，是張拉控制應(yīng)力值提高。3 預(yù)應(yīng)力損失由哪些

13、？減少各項(xiàng)損失的措施是什么？不同張拉方式損失是如何組合的？先張法、后張法的第一批、第二批預(yù)應(yīng)力損失分別是什么？答：張拉端錨具變形和鋼筋內(nèi)縮引起的預(yù)應(yīng)力損失l1;減少墊片，采用變形小的錨具，后張法采用兩端張拉預(yù)應(yīng)力鋼筋與孔管壁之間的摩擦力引起的預(yù)應(yīng)力損失l2;超張拉，兩端張拉混凝土加熱養(yǎng)護(hù)時(shí)，受張拉的鋼筋與承受拉力的設(shè)備之間的溫差引起的預(yù)應(yīng)力損失l3;采用兩階段升溫養(yǎng)護(hù)方法；預(yù)應(yīng)力鋼筋的應(yīng)力松弛引起的預(yù)應(yīng)力損失l4;超張拉混凝土收縮和徐變引起的預(yù)應(yīng)力損失l5；采用高標(biāo)號(hào)水泥，減少水泥用量，采用級(jí)配好的骨料，加強(qiáng)振搗，提高混凝土的密實(shí)性，加強(qiáng)養(yǎng)護(hù)，減少混凝土收縮，采用高效減水劑減少水灰比，控制混凝

14、土應(yīng)力，防止發(fā)生非線(xiàn)性徐變用螺旋式預(yù)應(yīng)力鋼筋作配筋的環(huán)形構(gòu)件，由于混凝土的局部擠壓引起的預(yù)應(yīng)力損失l6;直徑d越大損失越小，d較大時(shí)，l6忽略不計(jì)。 先張法構(gòu)件第一批預(yù)應(yīng)力損失：l1+l2+l3+l4;后張法構(gòu)件第一批預(yù)應(yīng)力損失：l1+l2;先張法構(gòu)件第二批預(yù)應(yīng)力損失：l5；后張法構(gòu)件第二批預(yù)應(yīng)力損失：l4+l5+l64張拉控制應(yīng)力為什么不能過(guò)大也不能過(guò)小？答：（1）太小就起不了提高有效應(yīng)力的作用；（2）con過(guò)大會(huì)：個(gè)別鋼筋可能被拉斷施工階段可能會(huì)引起構(gòu)件某些部位受拉甚至開(kāi)裂，還可能使后張法構(gòu)件端部混凝土產(chǎn)生局部受壓破壞 使開(kāi)裂荷載和破壞荷載相近，一旦出現(xiàn)裂縫，將很快破壞，即產(chǎn)生無(wú)預(yù)兆性的脆

15、性破壞 增大預(yù)應(yīng)力鋼筋的松弛損失。5單層廠(chǎng)房結(jié)構(gòu)作用荷載有哪些？各種荷載的傳遞路徑是怎樣的？答：恒載包括各種構(gòu)件、維護(hù)結(jié)構(gòu)及固定設(shè)備的自重;活載包括屋面活載、雪荷載、積灰荷載、風(fēng)荷載、吊車(chē)荷載等。橫、豎向荷載主要通過(guò)橫向平面排架傳至地基。縱向荷載通過(guò)縱向平面排架傳至地基。6柱間支撐作用：承受由抗風(fēng)柱和屋蓋橫向水平支撐傳來(lái)的山墻風(fēng)載，由屋蓋結(jié)構(gòu)傳來(lái)的縱向水平地震作用及由吊車(chē)梁傳來(lái)的吊車(chē)縱向水平制動(dòng)力，并將它們傳給基礎(chǔ)。柱間支撐作用是承受由抗風(fēng)柱和屋蓋橫向水平支撐傳來(lái)的山墻風(fēng)載，由屋蓋結(jié)構(gòu)傳來(lái)的的縱向水平地震作用及由吊車(chē)梁傳來(lái)的吊車(chē)縱向水平制動(dòng)力，并將它們傳給基礎(chǔ)，還能提高廠(chǎng)房的縱向剛度。7在確定

16、計(jì)算簡(jiǎn)圖時(shí)作了哪些假設(shè)？如何提取排架的計(jì)算簡(jiǎn)圖？答：做如下假定1柱下端嵌固于基礎(chǔ)中，固定端位于基礎(chǔ)頂面。2柱頂與屋架或屋面梁為鉸接，只能傳遞豎向軸力和水平剪力，不能傳遞彎矩。3橫梁為軸向剛度很大的剛性連桿。在假定基礎(chǔ)上得到橫向排架的計(jì)算模型，在該計(jì)算模型基礎(chǔ)上加以荷載就成為排架結(jié)構(gòu)的計(jì)算簡(jiǎn)圖。8牛腿的破壞形態(tài)有哪些？答：彎壓破壞；斜壓破壞；剪切破壞；此外還有因加載板過(guò)小而導(dǎo)致加載板下混凝土局部壓碎破壞，因縱向受拉鋼筋錨固不良而拔出等破壞。 9柱下獨(dú)立基礎(chǔ)的設(shè)計(jì)內(nèi)容有哪些？這些內(nèi)容滿(mǎn)足后能防止哪些破壞？基礎(chǔ)高度應(yīng)滿(mǎn)足哪兩個(gè)要求？答：內(nèi)容有:確定基礎(chǔ)底面尺寸和基礎(chǔ)高度；計(jì)算基礎(chǔ)底板配筋并采用必要的

17、構(gòu)造措施等。能夠防止柱周邊或變階處的截面產(chǎn)生沖切破壞。防止在基礎(chǔ)底板基凈反力作用下，因兩個(gè)方向均產(chǎn)生向上的彎曲而破壞。10什么是剛性基礎(chǔ)？什么是柔性基礎(chǔ)？答：剛性基礎(chǔ)是指用磚、石、灰土、混凝土等抗壓強(qiáng)度大而抗彎、抗剪強(qiáng)度小的材料做的基礎(chǔ)（受剛性角的限制）；柔性基礎(chǔ)是指用抗拉、抗彎、抗壓、抗剪均較好的鋼筋混凝土材料做的基礎(chǔ)。11框架結(jié)構(gòu)的布置方法有幾種？各種結(jié)構(gòu)布置方法有什么優(yōu)缺點(diǎn)？答：框架結(jié)構(gòu)有橫向承重布置（優(yōu)點(diǎn)：可以在一定程度上改善房屋橫向與縱向剛度相差較大的缺點(diǎn)，其聯(lián)系梁的截面高度一般比主梁小，窗戶(hù)尺寸可以設(shè)計(jì)得大些，室內(nèi)采光好，通風(fēng)好）、縱向承重布置（優(yōu)點(diǎn);便于管線(xiàn)沿縱向穿行，當(dāng)?shù)鼗胤?/p>

18、屋縱向不夠均勻時(shí)，縱向框架可在一定程度上調(diào)整這種不均勻性；缺點(diǎn)：房屋的橫向抗側(cè)移剛度?。╇p向承重布置（整體性受力好性能好，特別適合對(duì)房屋結(jié)構(gòu)的整體性要求較高和樓面荷載較大的情況下采用）12如何選取承重框架的計(jì)算單元?答：跨度：跨左右兩邊柱截面形心軸之間的距離；層高：底層柱高從基礎(chǔ)頂面算至柱頂標(biāo)高處；中間標(biāo)高：從下一層樓面標(biāo)高算至層面標(biāo)高；頂層標(biāo)高：從頂層樓面標(biāo)高算至層面標(biāo)高13框架在豎直荷載作用下內(nèi)力近似求解有哪些方法？該方法的假設(shè)條件是什么？ 答：分層法基本假定：在豎向荷載作用下，框架側(cè)移小， 因而忽略不計(jì)；每層梁上的荷載對(duì)其他各層梁的影響很小，可以忽略不計(jì)，因此每層梁上的荷載只在該層梁及與

19、該層相連的柱上 分配和傳遞。疊代法：基本假定：不考慮框架側(cè)移；考慮框架側(cè)移時(shí)；系數(shù)法：基本假定：兩個(gè)相鄰跨的跨長(zhǎng)相差不超過(guò)短跨跨長(zhǎng)的20%；活載與恒載之比不大于3； 荷載的均勻布置；框架梁截面為矩形時(shí)14挑梁、過(guò)梁應(yīng)進(jìn)行哪幾個(gè)方面計(jì)算？答：跳梁：抗顛覆計(jì)算；極限承載力計(jì)算；構(gòu)造要求過(guò)梁：極限承載力計(jì)算；構(gòu)造要求15砌體局壓破壞有哪些破壞特征？答：因豎向裂縫的發(fā)展而破壞；劈裂破壞；局部受壓面積附近的砌體壓壞。16影響砌體抗壓強(qiáng)度的主要因素有哪些？答：一、砌體材料的物理、力學(xué)性能：塊體和砂漿的強(qiáng)度; 塊體規(guī)整程度尺寸；砂漿的變形與和易性；二、砌體工程施工質(zhì)量：灰縫砂漿飽滿(mǎn)度；塊體砌筑時(shí)的含水率；灰

20、縫厚度；砌體組砌方法。17砌體受彎破壞形態(tài)及特征是怎樣的？答：分為三種破壞形態(tài):a) 當(dāng)截面內(nèi)的拉應(yīng)力使砌體沿齒縫截面破壞，稱(chēng)為砌體沿齒縫截面彎曲受拉； b) 砌體沿塊體縫面破壞，稱(chēng)為砌體沿塊體截面彎曲受拉；c) 砌體沿通縫截面破壞，稱(chēng)為砌體沿通縫截面彎曲受拉。18在哪些情況下需要考慮砌體抗壓強(qiáng)度設(shè)計(jì)值的調(diào)整系數(shù)？答：有吊車(chē)房屋砌體，跨度不小于9m的梁下燒結(jié)普通磚砌體，跨度不小于7.2m的梁下燒結(jié)多孔磚、蒸壓灰砂磚、蒸壓粉煤灰磚、混凝土和輕骨料混凝土砌塊砌體，a為0.9.對(duì)于無(wú)筋砌體構(gòu)件，其截面面積小于0.3m2時(shí)，a為其截面面積加0.7對(duì)于配筋砌體構(gòu)件，當(dāng)其截面面積小于0.2m2時(shí)，a為其截

21、面面積加0.8當(dāng)砌體用水泥砂漿砌筑時(shí)，隊(duì)表2-4表2-9的數(shù)值，a為0.9.隊(duì)表2-10的數(shù)值，a為0.8；對(duì)于配筋砌體構(gòu)件，當(dāng)其中的砌體采用水泥砂漿砌筑時(shí)，僅對(duì)砌體的強(qiáng)度設(shè)計(jì)值乘以調(diào)整系數(shù)a。當(dāng)施工質(zhì)量控制等級(jí)為c級(jí)時(shí)，a為0.89.當(dāng)驗(yàn)算施工中房屋的構(gòu)件時(shí)，a為1.119墻體布置方案有哪些？各自?xún)?yōu)缺點(diǎn)及應(yīng)用情況？答：橫墻承重（優(yōu)點(diǎn)：橫墻間距小且數(shù)量較多，橫向剛度較大、整體性好、抵抗風(fēng)荷載、地震作用以及調(diào)整地基不均勻沉降的能力較強(qiáng)，結(jié)構(gòu)簡(jiǎn)單以及施工方便，因縱墻不承重致建筑立面易處理以及門(mén)窗的布置和大小較靈活， 缺點(diǎn)：因縱墻較密，建筑平面布置不靈活。應(yīng)用：房間大小固定、橫墻間距較密的住宅、宿舍

22、、旅館以及辦公樓等）；縱墻承重（優(yōu)點(diǎn)：建筑平面靈活，與橫墻承重結(jié)構(gòu)相比，墻體材料用量較少、屋樓蓋構(gòu)件用料較多， 缺點(diǎn)：橫向剛度較差、縱墻上門(mén)窗洞口的布置大小受一定的限制。 應(yīng)用：用于開(kāi)間較大的教學(xué)樓、醫(yī)院、食堂、倉(cāng)庫(kù)）；縱橫墻承重（優(yōu)點(diǎn)：房屋沿縱、橫向剛度均較大且砌體應(yīng)力較均勻，具有較強(qiáng)的抗風(fēng)能力，占地面積相同的條件下，外墻面積較少， 應(yīng)用：多層塔式住宅等）；框架承重（優(yōu)點(diǎn)：內(nèi)部形成大空間，平面布置靈活，易滿(mǎn)足使用要求；與全框架結(jié)構(gòu)相比，可節(jié)約鋼材、水泥。降低房屋造價(jià)， 缺點(diǎn)：因橫墻較少，房屋的空間剛度較差。抵抗地震能力和地基不均勻沉降能力弱，應(yīng)用于商餐廳以及多層工業(yè)廠(chǎng)房等）四種型式。20在砌

23、體結(jié)構(gòu)中設(shè)置圈梁的目的是什么？答：增強(qiáng)房屋的整體剛度；防止地基不均勻沉降或較大振動(dòng)荷載等對(duì)房屋引起的不利影響；提高墻體抗剪、抗彎、承重的能力。，4剪力分配法求內(nèi)力：5截面尺寸估算(mm)：6反彎點(diǎn)法：頂層：柱抗側(cè)剛度：d=12ei/ 1驗(yàn)算柱的受壓承載力： 柱頂截面驗(yàn)算查表得到f=，沿截面長(zhǎng)邊方向按偏心受壓驗(yàn)算： ， ，沿截面短邊方向按軸心受壓驗(yàn)算：同上。2局部受壓承載力驗(yàn)算查表得到砌體抗壓強(qiáng)度設(shè)計(jì)值為f=， ，局部受壓承載力滿(mǎn)足要求。3排架上風(fēng)荷載標(biāo)準(zhǔn)值：，4剪力分配法求內(nèi)力：5截面尺寸估算(mm)：6反彎點(diǎn)法：頂層：柱抗側(cè)剛度：d=12ei/ 請(qǐng)您刪除一下內(nèi)容，o(_)o謝謝！2016年中

24、央電大期末復(fù)習(xí)考試小抄大全，電大期末考試必備小抄，電大考試必過(guò)小抄acetylcholine is a neurotransmitter released from nerve endings (terminals) in both the peripheral and the central nervous systems. it is synthesized within the nerve terminal from choline, taken up from the tissue fluid into the nerve ending by a specialized transpo

25、rt mechanism. the enzyme necessary for this synthesis is formed in the nerve cell body and passes down the axon to its end, carried in the axoplasmic flow, the slow movement of intracellular substance (cytoplasm). acetylcholine is stored in the nerve terminal, sequestered in small vesicles awaiting

26、release. when a nerve action potential reaches and invades the nerve terminal, a shower of acetylcholine vesicles is released into the junction (synapse) between the nerve terminal and the effector cell which the nerve activates. this may be another nerve cell or a muscle or gland cell. thus electri

27、cal signals are converted to chemical signals, allowing messages to be passed between nerve cells or between nerve cells and non-nerve cells. this process is termed chemical neurotransmission and was first demonstrated, for nerves to the heart, by the german pharmacologist loewi in 1921. chemical tr

28、ansmission involving acetylcholine is known as cholinergic. acetylcholine acts as a transmitter between motor nerves and the fibres of skeletal muscle at all neuromuscular junctions. at this type of synapse, the nerve terminal is closely apposed to the cell membrane of a muscle fibre at the so-calle

29、d motor end plate. on release, acetylcholine acts almost instantly, to cause a sequence of chemical and physical events (starting with depolarization of the motor endplate) which cause contraction of the muscle fibre. this is exactly what is required for voluntary muscles in which a rapid response t

30、o a command is required. the action of acetylcholine is terminated rapidly, in around 10 milliseconds; an enzyme (cholinesterase) breaks the transmitter down into choline and an acetate ion. the choline is then available for re-uptake into the nerve terminal. these same principles apply to cholinerg

31、ic transmission at sites other than neuromuscular junctions, although the structure of the synapses differs. in the autonomic nervous system these include nerve-to-nerve synapses at the relay stations (ganglia) in both the sympathetic and the parasympathetic divisions, and the endings of parasympath

32、etic nerve fibres on non-voluntary (smooth) muscle, the heart, and glandular cells; in response to activation of this nerve supply, smooth muscle contracts (notably in the gut), the frequency of heart beat is slowed, and glands secrete. acetylcholine is also an important transmitter at many sites in

33、 the brain at nerve-to-nerve synapses. to understand how acetylcholine brings about a variety of effects in different cells it is necessary to understand membrane receptors. in post-synaptic membranes (those of the cells on which the nerve fibres terminate) there are many different sorts of receptor

34、s and some are receptors for acetylcholine. these are protein molecules that react specifically with acetylcholine in a reversible fashion. it is the complex of receptor combined with acetylcholine which brings about a biophysical reaction, resulting in the response from the receptive cell. two majo

35、r types of acetylcholine receptors exist in the membranes of cells. the type in skeletal muscle is known as nicotinic; in glands, smooth muscle, and the heart they are muscarinic; and there are some of each type in the brain. these terms are used because nicotine mimics the action of acetylcholine a

36、t nicotinic receptors, whereas muscarine, an alkaloid from the mushroom amanita muscaria, mimics the action of acetylcholine at the muscarinic receptors. acetylcholine is the neurotransmitter produced by neurons referred to as cholinergic neurons. in the peripheral nervous system acetylcholine plays

37、 a role in skeletal muscle movement, as well as in the regulation of smooth muscle and cardiac muscle. in the central nervous system acetylcholine is believed to be involved in learning, memory, and mood. acetylcholine is synthesized from choline and acetyl coenzyme a through the action of the enzym

38、e choline acetyltransferase and becomes packaged into membrane-boundvesicles. after the arrival of a nerve signal at the termination of an axon, the vesicles fuse with the cell membrane, causing the release of acetylcholine into thesynaptic cleft. for the nerve signal to continue, acetylcholine must

39、 diffuse to another nearby neuron or muscle cell, where it will bind and activate areceptorprotein. there are two main types of cholinergic receptors, nicotinic and muscarinic. nicotinic receptors are located at synapses between two neurons and at synapses between neurons and skeletal muscle cells.

40、upon activation a nicotinic receptor acts as a channel for the movement of ions into and out of the neuron, directly resulting indepolarizationof the neuron. muscarinic receptors, located at the synapses of nerves with smooth or cardiac muscle, trigger a chain of chemical events referred to as signa

41、l transduction. for a cholinergic neuron to receive another impulse, acetylcholine must be released from the receptor to which it has bound. this will only happen if the concentration of acetylcholine in the synaptic cleft is very low. low synaptic concentrations of acetylcholine can be maintained v

42、ia a hydrolysis reaction catalyzed by the enzyme acetylcholinesterase. this enzyme hydrolyzes acetylcholine into acetic acid and choline. if acetylcholinesterase activity is inhibited, the synaptic concentration of acetylcholine will remain higher than normal. if this inhibition is irreversible, as

43、in the case of exposure to many nerve gases and some pesticides, sweating, bronchial constriction, convulsions, paralysis, and possibly death can occur. although irreversible inhibition is dangerous, beneficial effects may be derived from transient (reversible) inhibition. drugs that inhibit acetylc

44、holinesterase in a reversible manner have been shown to improve memory in some people with alzheimers disease. abstract expressionism, movement of abstract painting that emerged in new york city during the mid-1940s and attained singular prominence in american art in the following decade; also calle

45、d action painting and the new york school. it was the first important school in american painting to declare its independence from european styles and to influence the development of art abroad. arshile gorky first gave impetus to the movement. his paintings, derived at first from the art of picasso

46、, mir, and surrealism, became more personally expressive. jackson pollocks turbulent yet elegant abstract paintings, which were created by spattering paint on huge canvases placed on the floor, brought abstract expressionism before a hostile public. willem de koonings first one-man show in 1948 esta

47、blished him as a highly influential artist. his intensely complicated abstract paintings of the 1940s were followed by images of woman, grotesque versions of buxom womanhood, which were virtually unparalleled in the sustained savagery of their execution. painters such as philip guston and franz klin

48、e turned to the abstract late in the 1940s and soon developed strikingly original stylesthe former, lyrical and evocative, the latter, forceful and boldly dramatic. other important artists involved with the movement included hans hofmann, robert motherwell, and mark rothko; among other major abstrac

49、t expressionists were such painters as clyfford still, theodoros stamos, adolph gottlieb, helen frankenthaler, lee krasner, and esteban vicente. abstract expressionism presented a broad range of stylistic diversity within its largely, though not exclusively, nonrepresentational framework. for exampl

50、e, the expressive violence and activity in paintings by de kooning or pollock marked the opposite end of the pole from the simple, quiescent images of mark rothko. basic to most abstract expressionist painting were the attention paid to surface qualities, i.e., qualities of brushstroke and texture;

51、the use of huge canvases; the adoption of an approach to space in which all parts of the canvas played an equally vital role in the total work; the harnessing of accidents that occurred during the process of painting; the glorification of the act of painting itself as a means of visual communication

52、; and the attempt to transfer pure emotion directly onto the canvas. the movement had an inestimable influence on the many varieties of work that followed it, especially in the way its proponents used color and materials. its essential energy transmitted an enduring excitement to the american art sc

53、ene. science and technology is quite a broad category, and it covers everything from studying the stars and the planets to studying molecules and viruses. beginning with the greeks and hipparchus, continuing through ptolemy, copernicus and galileo, and today with our work on the international space

54、station, man continues to learn more and more about the heavens. from here, we look inward to biochemistry and biology. to truly understand biochemistry, scientists study and see the unseen bystudying the chemistry of biological processes. this science, along with biophysics, aims to bring a better

55、understanding of how bodies work from how we turn food into energy to how nerve impulses transmit.analytic geometry, branch ofgeometryin which points are represented with respect to a coordinate system, such ascartesian coordinates, and in which the approach to geometric problems is primarily algebr

56、aic. its most common application is in the representation of equations involving two or three variables as curves in two or three dimensions or surfaces in three dimensions. for example, the linear equationax+by+c=0 represents a straight line in thexy-plane, and the linear equationax+by+cz+d=0 repre

57、sents a plane in space, wherea, b, c,anddare constant numbers (coefficients). in this way a geometric problem can be translated into an algebraic problem and the methods of algebra brought to bear on its solution. conversely, the solution of a problem in algebra, such as finding the roots of an equa

58、tion or system of equations, can be estimated or sometimes given exactly by geometric means, e.g., plotting curves and surfaces and determining points of intersection. in plane analytic geometry a line is frequently described in terms of its slope, which expresses its inclination to the coordinate axes; technically, the slopemof a straight line is the (trigonometric) tangent of the angle it makes with thex-axis. if the line is parallel to thex-axis, its slope is zero. two or more lines with equal slopes are parallel to one a