电大建筑结构期末重点复习考试小抄
电大建筑结构期末复习参考资料考试小抄 判断题 (×)1.钢筋混凝土构件采用HRB335级钢筋时,混凝土强度等级不宜低于C15。
(×)2.同截面、同材料、同纵向钢筋的螺旋箍筋钢筋混凝土柱的承载力比普通箍筋钢筋混凝土柱的承载力低。
(√)3.在正常实用极限状态实用设计表达式中,不需考虑结构重要性系数。
(×)4.受弯构件的斜截面承载力随剪跨比的增大而减少。
(×)5.受弯构件的配筋率是钢筋截面面积与构件的全截面面积之比。
(√)
6.计算剪跨比为集中荷载作用点至支座的距离a和梁有效高度h0的比值。
(×)7.配筋率是钢筋截面面积与结构的全截面面积之比。
(√)8.斜拉破坏多发生在剪跨比较大或腹筋配置过少时。
(×)9.剪压破坏是塑性破坏,斜拉破坏和斜压破坏是脆性破坏。
(√)10.小偏压构件中离轴力较远一侧的钢筋,破坏时,不论其受压或受拉,其应力一般都达不到屈服强度。
(√)11.结构的极限状态分成承载能力极限状态和正常使用极限状态。
(×)12.可以通过最小配筋率来防止剪压破坏的发生。
(√)13.混凝土受压区高度超过翼缘高度的为第二类T形截面。
(×)14.其他条件相同时,采用水泥砂浆与混合砂浆砌筑的砌体强度相等。
(√)15.在预应力混凝土构件中,可采用高强度等级的钢筋和混凝土。
(√)16.规范按照房屋的屋盖和楼盖类别和横墙间距划分砌体结构的静力计算方案。
(×)17.纵向框架承重有利于增加房屋横向刚度,但主梁截面尺寸较大。
(×)18.弹性静力计算方案的结构,在水平荷载作用下,屋面结构可看成外纵墙的不动铰支座。
二、选择题 1.我国规范采用(A)强度作为混凝土各种力学指标的代表值。
A.立方体抗压强度标准值 B.轴心抗压强度 C.轴心抗拉强度 D.劈拉强度 2.对于有明显流幅的钢筋,其设计强度取值的依据一般是(C)。
A.最大应变对应的应力 B.极限抗拉强度 C.屈服强度 D.比例极限 3.混凝土的强度等级为C30,则下列说法正确的是(A)。
A.其立方体抗压强度标准值达到了30N/mm2 B.其轴心抗压强度达到了30N/mm2 C.其立方体抗压强度标准值达到了30N/m2 D.其轴心搞拉强度达到了30N/m2 4.永久荷载效应控制的内力组合,其永久荷载和活荷载的分项系数取为(A)。
A.1.35T 1.4 B.1.2和1.4 C.1.2和1.3 D.1.2和1.35 5.在一类环境类别下,梁的保护层的最小厚度规定为(B)。
A.不小于钢筋直径和20mm B. 不小于钢筋直径和25mm C. 不小于钢筋直径和30mm D. 不小于钢筋直径和40mm 6.一类环境中,布置有单排纵向受力钢筋的梁,其截面有效高度一般可取(B)。
A.h-60 B.h-35 C.h-20 D.h 7.受弯混凝土构件,若其纵筋配筋率小于最小配筋率,我们一般称之为(B)。
A.适筋梁 B.少筋梁 C.超筋梁 D.无腹筋梁 8.一般受弯构件当V≤0.7bh0ƒt时(C)。
A.可直接按最小配箍率配箍 B.直接按规范构造要求的最大箍筋间距和最小箍筋直径配箍率 C.按箍筋的最大间距和最小直径配筋,并验算最小配箍率 D.按计算配箍 9.轴心受压构件的稳定系数主要与(C)有关。
A.混凝土强度 B.配筋率 C.长细比 D.荷载 10.双筋矩形截面梁,正截面承载力计算公式的第二个适用条件的物理意义是(C)。
A防止出现超筋破坏 B.防止出现少筋破坏 C.保证受压钢筋达到规定的抗压设计强度 D.保证受拉钢筋达到规定的抗拉设计强度 11.混凝土规范规定,当矩形截面偏心受压构件的长细比l0/h(C)时,可以取=1。
A.≤8 B.≤17.5 C.≤5 D≤6 12.对于对称配筋的钢筋混凝土受压柱,大小偏压构件的判断条件是(C)。
A.时,为大偏压构件 B.时,为大偏压构件 C.时,为大偏压构件 D.时,为大偏压构件 13.普通砖砌体结构,构件截面面积A<0.3㎡时,其强度设计值应乘以调整系数(C)。
A.0.75 B.0.89 C.0.7+A D.0.9 14.影响砖砌体抗压强度的因素有(C)。
A.砂浆的强度等级是影响砌体抗压强度的主要因素 B.砂浆的品种对砌体的抗压强度没有影响 C.提高砖的厚度可以提高砌体的抗压强度 D.砌筑质量好坏对砌体强度没有影响 15.适筋梁的破坏特征是(D)。
A.破坏前无明显的预兆 B.受压钢筋先屈服,后压区混凝土被压碎 C.是脆性破坏 D.受拉钢筋先屈服,后压区混凝土被压碎 16.在钢筋混凝土双筋梁和大偏压构件的正截面承载力计算中,要求受压区高度,目的是为了(A)。
A.保证受压钢筋在破坏时能达到其抗压强度设计值 B.防止受压钢筋压屈C.避免保护层剥落 D.保证受压钢筋在破坏时候能达到其极限抗压强度 17.条件满足的无腹筋梁,发生斜压、剪压、斜拉破坏形态时,梁的斜截面抗剪承载力的大致关系是(A)。
A.斜压破坏的承载力>剪压破坏的承载力>斜拉破坏的承载力 B.剪压破坏的承载力>斜压破坏的承载力>斜拉破坏的承载力 C.斜拉破坏的承载力>斜压破坏的承载力>剪压破坏的承载力 D.剪压破坏的承载力>斜拉破坏的承载力>斜压破坏的承载力 18.在排架结构中,上柱柱间支撑和下柱柱间支撑的设置位置合理的是(B)。
A.上柱柱间支撑设在伸缩缝区段中部的柱间 B.上柱柱间支撑设在伸缩缝区段中部和两端的柱间 C.下柱柱间支撑设在伸缩缝区段两端的柱间 D.下柱柱间支撑设在伸缩缝区段中部和两端的柱间 19.(A)房屋的静力计算时,墙、柱可作为以屋盖(楼盖)为不动铰支座的竖向构件计算。
A.刚性方案 B.弹性方案 C.刚弹性方案 D.刚性和刚弹性方案 三、简答题 1.试述随着配筋率的变化,梁的正截面破坏形式的变化。
答:随着配筋率的增大,出现少筋适筋、超筋三种破坏形式,少筋梁的破坏特征为一旦出现裂缝,裂缝迅速开展,构件即宣告破坏;
适筋梁的破坏特征为受拉钢筋先屈服,后压区混凝土被压碎,为塑性破坏,破坏前有预兆;
超筋梁的破坏特征为受压区混凝土被压碎,此时受拉钢筋尚未达到屈服强度,少筋和超筋破坏均为脆性破坏。
2.适筋梁从加荷开始到构件破坏经历的三个阶段分别是什么?每一个阶段末的应力状态可以作为什么验算的依据? 答:1)第一阶段一弹性阶段,此阶段截面的应力状态是抗裂验算的依据。
2)第二阶段一带裂缝工作阶段,此阶段截面的应力状态可以作为裂缝宽度和变形验算的依据。
3)第三阶段一破坏阶段,这时的应力状态可作为构件承载力计算的依据。
3.简述大小偏压的破坏特征。
答:大偏心受压构件的破坏特征为受拉钢筋先屈服,后受压区混凝土被压碎和受压钢筋屈服,为塑性破坏,破坏前有明显预兆,钢筋强度得以充分利用;
小偏压构件破坏特征为受压区混凝土被压碎,受压钢筋屈服,而受拉钢筋不论受压或受拉,均未达到屈服强度,为脆性破坏,受拉钢筋强度得不到充分利用。
4.简述梁的斜截面的三种破坏形态及其破坏条件。
答:梁斜截面的三种破坏形态及其破坏条件:
1)剪跨比较小时或剪跨比适中但配箍率过大时,发生斜压破坏;
2)剪跨比较大或配箍率较小时,发生斜拉破坏;
3)剪跨比适中,配箍率合适时,发生剪压破坏。
5.在受弯构件的设计中,为什么不允许出现少筋梁和超筋梁? 答:少筋梁的破坏特征为一旦出现裂缝,裂缝迅速开展,构件即宣告破坏;
超筋梁的破坏特征为受压区混凝土被压碎,此时受拉钢筋尚未达到屈服强度;
少筋和超筋破坏均为脆性破坏,破坏前没有预兆,因此在受弯构件的设计中不允许出现少筋梁和超筋梁。
6.砌体房屋的静力计算方案可划分为哪三种?规范是如何划分静力计算方案的? 答:按照房屋空间刚度的大小房屋的静力计算方案可划分为弹性方案、刚性方案和刚弹性方案。为便于应用,规范按照屋盖(楼盖)的类别和横墙的间距来划分静力计算方案。
四计算题 1.单筋矩形截面简支梁,截面尺寸b×h=250×500mm,采用C30砼,HRB335级纵向受力钢筋,承受弯距设计值M=250kN·m的作用,已在受拉区配置有4根直径25mm的钢筋(As=1964mm2),试验算截面安全与否。
已知,ρmin=0.2%,ζb=0.550,h0=465mm, 。
解:
1.验算梁是否会超筋 2.验算梁是否会少筋 不会少筋梁 3.计算梁的承载力 =225.42KN-m<M=250KN-m 梁截面不安全。
2.某轴心受压柱,截面尺寸b×h=400mm×500mm,此柱承受的轴力设计值N=4000KN,计算长度ι0=4m,采用C35砼,HRB400级纵向受力钢筋,试校核此柱是否安全。
已知:
8 10 12 1.0 0.98 0.95 提示:。
解:
1.计算柱的长细比 2.查表得柱的稳定性系数 Ф=0.98 计算NU NU=0.9×0.98×(16.7×400×500+360×1964)
=35.69KN<N=4000KN 此柱不安全。
3.某单层食堂,横墙间距S=25m,为刚性方案,H0H,外纵墙承重且每3.3m开间有一个2.1m的窗洞,墙高H=4.2m,墙厚370mm,砂浆采用M5。试验算外纵墙的高厚比是否满足要求。[β]=24 答案:
外纵墙的高厚比满足要求。
请您删除一下内容,O(∩_∩)O谢谢!!!2015年中央电大期末复习考试小抄大全,电大期末考试必备小抄,电大考试必过小抄请您删除一下内容,O(∩_∩)O谢谢!!!2015年中央电大期末复习考试小抄大全,电大期末考试必备小抄,电大考试必过小抄The battle for young viewers CCTV is embracing Internet culture and working with independent producers on TV shows to woo audiences under 35. Han Bing bin reports. After charming audiences with his warm smile for 14 years, China Central Television host Li Jiaming recently found himself targeted by a group of young netizens unhappy with his style. The complaints came after Li hosted the premiere of Rising Star on Oct 31. It is a singing competition show that originated in Israel. Many young netizens found his hosting style slow and boring and mocked it as “CCTV evening gala style“. They even initiated an online campaign to replace him. The 40-year-old host's reaction to the criticism was surprising. During the second episode, he jokingly called himself “the slow Jiaming“ and acted much younger, talking faster and louder. “It's like selling a product. When the customers file a complaint, you must change,“ says Li. “In the Internet age, you get feedback very quickly. These young people are so cute. When you're willing to change for them, they will quickly like you back.“ In order to win more young viewers, CCTV is relying on programs such as Rising Star to embrace Internet culture. In Rising Star, a studio audience and fans watching on television vote for their favorite singers in real time, using the instant-messaging app WeChat. Rising Star was designed to be a live broadcast, but the Chinese version isn't because of policy reasons. Still, WeChat votes by viewers at home are still a major factor in determining which contestants advance to the next round. In the show's latest episode, more than 6.5 million votes were cast via WeChat. “Now the competition among entertainment shows is very fierce. Audiences have more diverse needs. CCTV needs to embrace an open attitude, interact with young audiences and blend with the Internet,“ says Lyu Yitao, director of CCTV's entertainment channel. The producer of Rising Star, Enlight Media, says the program will have “a phenomenal effect“ given CCTV's audience base nationwide. “But it comes with a challenge,“ says Zhang Hang, chief producer of the program and CEO of Enlight Media's TV business. Unlike top-ranking provincial satellite channels such as Hunan TV, which have a large base of young fans thanks to a series of phenomenally popular entertainment and reality shows, CCTV productions are usually more conservative and serious, and thus have a much older audience base. “If we were to run this program on Hunan, we may attract twice as many viewers,“ says Zhang. “But since we didn't make it there, we now have to make the best out of the given conditions. And it means we have to make certain compromises.“ When the current season of Rising Star ends, Zhang says his company will conduct an overall evaluation of the program and make adjustments for future seasons. Although audience ratings haven't lived up to Zhang's expectations, he says the program has already helped CCTV attract more young people. According to Enlight Media, the number of people ages 15 to 35 who watched the first episode of Rising Star was 76 percent higher than the usual audience for CCTV entertainment productions. In order to attract young audiences, CCTV has been working with independent production companies. As one of CCTV's closest partners, Enlight Media has produced several entertainment and reality shows for the company's channels, including the Chinese version of The Biggest Loser on CCTV's business channel and an original teenager talent show Shaonian Zhongguo-qiang (Strong Young Chinese) on CCTV1. This year CCTV also licensed EE-Media, the producer of the popular Super Girl talent shows, to produce the talk show Hi! 2014, hosted by Taiwan pop star Harlem Yu and one of China's most popular TV stars Xie Na. The show is geared toward younger audiences. Canxing Productions, which rose to fame with the success of its Voice of China series on Zhejiang TV, also produced two talent shows for CCTV. One is an original production called Songs of China, which ended up as one of CCTV's most watched programs of 2014. The State Administration of Press, Publication, Radio, Film and Television announced earlier this year that, starting in 2015, only one music talent show can be aired nationwide during prime time each season, and there can be only one program based on foreign formats each year. However, domestic media report that such policies don't apply to CCTV, meaning it will become a highly desired platform by production companies. Wang Changtian, CEO of Enlight Media, confirmed to the Shanghai Securities News that its programs scheduled to air on CCTV next year, which include at least two reality shows, won't be affected. A kung fu-themed reality show, produced by Canxing, is also reportedly scheduled to run on CCTV next year. CCTV is “very active. The level of its acceptance of new ideas is even beyond my imagination,“ says Zhang Hang. “Our cooperation with CCTV will surely continue.“ When winter comes, nothing is more relaxing than a hot spring bath. For thousands of years, natural mineral-rich hot spring baths have also been used to relieve health ailments. The water found in natural hot springs contains a variety of different minerals, and the most common one is sulfur. It has a “rotten egg“ smell but is excellent for skin. The sulfur-containing water might be just what the doctor ordered when it comes to relieving pain, stress, itchy skin, arthritis and more. Hot springs resorts are thriving as biting cold winter arrives. Here we take a look at some of the best natural hot springs China has to offer.
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