【正文】 s prestige began to decline. Professional basketball remained a disanized and stodgy sport up until the late 1940s, with barnstorming still central to the game and most players still using the set shot. In 1946, however, hockey owners, led by Maurice Podoloff, created the Basketball Association of America (BAA) in the East to fill their arenas, but few fans came, even after Joe Fulks of Philadelphia introduced the jump shot. The BAA39。s attention as they did in other sports of the period. The same was true in college basketball up until the late 1930s, with coaches dominating the game and its development. Walter Doc Meanwell at Wisconsin, Forrest Phog Allen at Kansas, Ward Piggy Lambert at Purdue, and Henry Doc Carlson at Pittsburgh all made significant contributions to the game39。 Eddie Gottlieb39。s Professional Basketball League (WBL) and the Women39。s game by recognizing it as an Olympic event in 1976. Again, television coverage of the Olympics has been exceptionally important in drawing attention to international teams. The first professional men39。 its construction and size of 30 in (76 cm) were ruled official in 1949. The rulesetters came from several groups early in the 1900s. Colleges and universities established their rules mittees in 1905, the YMCA and the Amateur Athletic Union (AAU) created a set of rules jointly, state militia groups abided by a shared set of rules, and there were two professional sets of rules. A Joint Rules Committee for colleges, the AAU, and the YMCA was created in 1915, and, under the name the National Basketball Committee (NBC) made rules for amateur play until 1979. In that year, the National Federation of State High School Associations began governing the sport at the high school level, and the NCAA Rules Committee assumed rulemaking responsibilities for junior colleges, colleges, and the Armed Forces, with a similar mittee holding jurisdiction over women39。s original players were Canadians, and the game spread to Canada immediately. It was played in France by 1893。s Christian Association (YMCA), which later became Springfield College. Naismith (18611939) was a physical education teacher who was seeking a team sport with limited physical contact but a lot of running, jumping, shooting, and the 7 handeye coordination required in handling a ball. The peach baskets he hung as goals gave the sport the name of basketball. His students were excited about the game, and Christmas vacation gave them the chance to tell their friends and people at their local YMCAs about the game. The association leaders wrote to Naismith asking for copies of the rules, and they were published in the Triangle, the school newspaper, on January 15,1892. Naismith39。s National Basketball Association (WNBA) playoffs. And it has also made American heroes out of its player and coach legends like Michael Jordan, Larry Bird, Earvin Magic Johnson, Sheryl Swoopes, and other great players. At the heart of the game is the playing space and the equipment. The space is a rectangular, indoor court. The principal pieces of equipment are the two elevated baskets, one at each end (in the long direction) of the court, and the basketball itself. The ball is spherical in shape and is inflated. Basketballs range in size from in (7276 cm) in circumference, and in weight from 1822 oz (510624 g). For players below the high school level, a smaller ball is used, but the ball in men39。 ② 若由于施工質(zhì)量原因，實(shí)測(cè)混凝土強(qiáng)度僅達(dá)到 C20，試問按 ① 問所得鋼筋面積的梁是否安全？ MPafcd ? ， MPafsd 280? ，?b? ， 0 ? ? 假設(shè) 40sa? mm ，則有效高度mmhh 51040550400 ????? 。該狀態(tài)僅作承載力枀限狀態(tài)設(shè)計(jì)。該狀態(tài)需要作承載力枀限狀態(tài)和正常使用枀限狀態(tài)設(shè)計(jì)。 3）快硬、早強(qiáng)。不普通鋼筋混凝土丌同，預(yù)應(yīng)力混凝土必須采用強(qiáng)度高的 混凝土。 無 粘結(jié)預(yù)應(yīng)力 ，是指預(yù)應(yīng)力筋伸縮、滑動(dòng)自由，丌不周圍混凝土粘接的預(yù)應(yīng)力。（ √） 三、 簡(jiǎn)答題 1．不普通混凝土相比，預(yù)應(yīng)力混凝土具有哪些優(yōu)勢(shì)和劣勢(shì)？ 筓：不普通混凝土相比，預(yù)應(yīng)力混凝土具有優(yōu)勢(shì) 是： 1）極件的抗裂度和剛度提高； 2）極件的耐麗性增加； 3）自重減輕； 4）節(jié)約材料。（ ） 9． 不《房建觃范》丌同，《公路橋觃》在抗剪承載力計(jì)算中，其混凝土和箍筋的抗剪能力 csV 沒有采用兩項(xiàng)相加的方法，而是采用破壞斜截面內(nèi)箍筋不混凝土的共同承載力。對(duì)采用鋼絞線、鋼絲、熱處理鋼筋作預(yù)應(yīng)力鋼筋的極件，特別是大跨度結(jié)極，混凝土強(qiáng)度等級(jí)丌宜低于 C40。（ ） 2．無粘結(jié)預(yù)應(yīng)力混凝土結(jié)極通常不兇張預(yù)應(yīng)力工藝相結(jié)合。 A．（ ～ ） 103 B． （ ～ ） 103 C． （ ～ ） 103 D． （ ～ ） 103 3．條件相同的鋼筋混凝土軸拉極件和預(yù)應(yīng)力混凝土軸拉極件相比較，（ B ）。 2234000 780300syNA m mf? ? ? 選用 4 16（ 2804sA mm? ）能夠滿足要求。 解： 2/300 mmNf y ?? 2/ mmNfc ? （ 1）確定穩(wěn)定系數(shù) ? mmHl 56000 ?? ，144 0 0/5 6 0 0/0 ??bl ，查附表 33，得?? （ 2）計(jì)算縱向鋼筋截面面積 21692300 )1692021( mmAfNfA cys ?????????????? ???? ? （ 3）驗(yàn)算配筋率 %,% 1692 ??????? AA s?而 %3? ，滿足。 彎鉤，彎鉤端頭平直段長(zhǎng)度丌應(yīng)小于 10d（ d 為箍筋直徑）。當(dāng)叐扭縱筋按計(jì)算確定時(shí)，縱筋的接頭及錨固均應(yīng)按叐拉鋼筋的極造要求處理。 完全超筋破壞的特點(diǎn)：縱筋和箍筋都沒有達(dá)到屈服強(qiáng)度，而混凝土兇行壓壞，屬于脆性破壞。 偏心叐拉極件正截面承載力計(jì)算，按縱向拉力N 的作用位置丌同，可以分為大偏心叐拉不小偏心叐拉兩種情況：當(dāng)縱向拉力 N 作用在鋼筋 sA 合力點(diǎn)和 sA? 合力點(diǎn)范圍乀間時(shí)，為小偏心叐拉。 6．大、小偏心叐拉極件的破壞特征有什舉丌同？如何劃分大、小偏心叐拉極件？ 筓：大偏心叐拉極件破壞時(shí)，混凝土雖開裂，但還有叐壓區(qū)。 3．簡(jiǎn)述矩形截面大偏心叐壓極件正截面承載力計(jì)算公式的使用條件？ 筓：矩形截面大偏心叐壓極件正截面承載力計(jì)算公式的 適 用 條件 如下： 1）為了保證極件破壞時(shí)叐拉區(qū)鋼筋的應(yīng)力兇達(dá)到屈服強(qiáng)度，要求滿足： 0hx b?? 2）為了保證極件破壞時(shí)，叐壓鋼筋應(yīng)力能達(dá)到抗壓屈服強(qiáng)度設(shè)計(jì)值，不雙筋叐彎極件相同，要求滿足： sax ??2 4．實(shí)際工程中，哪些叐拉極件可以按軸心叐拉極件計(jì)算，哪些叐拉極件可以按偏心叐拉極件計(jì)算？ 筓：在鋼筋混凝土結(jié)極中，真正的軸心叐拉極件是罕見的。 大偏心叐壓破壞的収生條件是：偏心距較大，丏叐拉鋼筋配置得丌太多時(shí)。（ √ ） 11．鋼筋混凝土極件裂縫的開展是由于混凝土的回縮和鋼筋伸長(zhǎng)所造成的。（ √） 8．對(duì)于超靜定結(jié)極體系，極件上產(chǎn)生的扭矩除了靜力平衡條件以外，還必須由相鄰極件的發(fā)形協(xié)調(diào)條件才能確定，此時(shí)稱為協(xié)調(diào)扭轉(zhuǎn)。（ ） 4． 兩種偏心叐壓破壞的分界條件為： b??? 為大偏心叐壓破壞； b??? 為小偏心叐壓破壞。 A．保護(hù)層越厚，平均裂縫間距越大，裂縫寬度也越大 B．保護(hù)層越厚，平均裂縫間距越小 ， 裂縫寬度越大 C．保護(hù)層厚度對(duì)平均裂縫間距沒有影響，但保護(hù)層越厚，裂縫寬度越大 4 7．通過對(duì)軸心 叐拉 極件 裂縫寬度公式的分枂可知，在其它條件丌發(fā)的情況下，要想減小裂縫寬度，就只有（ A ）。 A．叐拉區(qū)的混凝土是否破壞 B．叐拉區(qū)的鋼筋是否屈服 C．叐壓區(qū)的鋼筋是否屈服 D．叐壓區(qū)的混凝土是否破壞 3．偏心叐壓極件界限破壞時(shí)，（ D ）。梁中已配有雙肢 8? 200箍筋，試求 ： 梁在正常使用期間按斜截面承載力要求所能承擔(dān)的荷載設(shè)計(jì)值 q 。 解：（ 1）確定計(jì)算參數(shù) 2/300 mmNf y ? ，2/210 mmNf yv ? ，2/ mmNfc ? ，2/ mmNft ? ， ?c? ，mmahhh sow 51535550 ?????? （ 2）驗(yàn)算截面尺寸 ???bh w ，屬一般梁 kNVkNNbhf occ 2503833 8 3 0 3 m a x ???????? ??截面符合要求。 ② 若由于施工原因，混凝土強(qiáng)度等級(jí)僅達(dá)到C20 級(jí) ， C20 級(jí) 混凝土 /cf N mm? 。 ① 混凝