【正文】 s public security bureau shows some 100 foreign visitors enjoyed the 72hour policy by the end of March, most of them from the United States, the United Kingdom and Germany. Chengdu also reported robust growth in its overall tourist industry last year. Official statistics show that it received some 150 million tourists last year, an increase of 28 percent from 2021. Around million came from abroad, an increase of 12 percent. Total revenue from tourism surpassed 133 billion yuan ($). During his visit to Kazakhstan in September, Chinese President Xi Jinping proposed that China and Central Asia join hands to build a Silk Road economic belt to boost cooperation. The idea has been w idely echoed in。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。s level of internationalization. The policy will also bring direct economic revenue, Li said. Chengdu has many cultural legacies and is also a paradise for panda lovers with the world39。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。 Jingdezhen raises porcelain standard City39。s 39。porcelain capital39。 ①受力分析：剪力 Q— PkN )1209060( ???? pp eF kM ②焊縫的有效截面 cm? cmS x ????? ③求 P 由 得 kNp ? 由 得 故焊縫所能承受的荷載 kNP ? MP apWM 10270 33m a x ?????? ? ?? 3????I 2cmhIW x ????kNp ? 9 請刪除 O(∩ _∩ )O 謝謝： Foreigners flock to China39。每題 l5分 )1．解： (1)計算混凝土受壓區(qū)高度 X由 a=40mm 則有效高度 ho=50040=460mm 由 )2(11 xhbxRrM ac ?? 得 )2460( 11090 6 xx ????? 解方程 (2)計算受拉鋼筋截面面積 Ag 由 AgRg=R。 。因此，砌體結(jié)構(gòu)以承受壓力為主。 答：與普通鋼筋混凝土結(jié)構(gòu)相比，預應力混凝土結(jié)構(gòu)可以使混凝土不出現(xiàn)拉應力 (或允許出現(xiàn)拉應力限制應力值或允許出現(xiàn)裂縫限制裂縫寬度 )，因而大大改善了結(jié)構(gòu)的工作性能。 2．答：為了便于應用材料力學中勻 質(zhì)梁的公式，在鋼筋混凝土結(jié)構(gòu)計算中，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。 (4)配箍率和箍筋強度：配箍率mx與箍筋強度 R。 ． (2)混凝土強度 R：梁的抗剪承載力隨混凝土強度提高而提高。每題 3 分 ) 1． B 2． C3． A4． C5． B6． D 7． C8． B9． C10． C 二、判斷題 (20分。試求焊縫連 接所能承受的荷載 P。 ]一 145MPa，[r]一 85MPa。 2．一連接的構(gòu)造如圖所示，兩塊 A板用對接焊縫與立柱焊連， 8板與 A 板用 8個高強螺栓連接。；。一丫。試用基本公式求所需的鋼筋面積 Ag(設 a=40mm，毛。一 llMPa)和 Ⅱ 級鋼筋 (R9一 340MPa)承受計算彎矩 Mi90kN ( ) 10．組合結(jié)構(gòu)充分利用了鋼與混凝土結(jié)構(gòu)性能，因此受力比較合理。 ( ) 8．強度、剛度、穩(wěn)定性是鋼結(jié)構(gòu)設計必須考慮的幾個方面。 ( ) 7．砌體結(jié)構(gòu)的特點是抗壓承載 力、抗剪承載力都高。 ( ) 5．預應力混凝土的本質(zhì)就是在混凝土結(jié)構(gòu)承載前施加一定的壓力，使其抵消或減小外荷載產(chǎn)生的拉應力。 ( ) 3．混凝土結(jié)構(gòu)出現(xiàn)裂縫并不影響使用，因此不必要對裂縫進行限制。 A．斜拉破壞 B．斜壓破壞 C．剪壓破壞 D．局壓破壞 二、判斷題 (20分，每題 2 分 ) 1．單筋矩形截面梁是指矩形截面梁中只有一根受力鋼筋。 A．矩形截面 z0／ ^≤8 B．矩形截面 l0／ ^7 C．矩形截面 l0／ h8 D．矩形截面％／矗 ≤78 ．利用鋼材約束，將混凝土由單向受壓轉(zhuǎn)變?yōu)槿蚴軌旱慕M合結(jié)構(gòu)稱為 ( )。 A．剪跨比很小時 B．剪跨比較大且箍筋數(shù)量較少時 C．與剪跨比無關 D．箍筋數(shù)量很多時 6．鋼筋混凝土結(jié)構(gòu)對鋼筋性能的要求不包括 ( )。 A．節(jié)省鋼材 B裂縫寬度小 C．承載 力大 D．撓度小 4．臨時結(jié)構(gòu)廣泛采用的鋼結(jié)構(gòu)連接方式為 ( )。 A．混凝土的軸心抗壓強度 B．混凝土的立方體強度 C．混凝土的抗拉強度 D．復合應力下的混凝土強度 2．采用兩端張拉可減小 ( )應力損失。 由 則有效高度 由 得 解方程得 分 ) (2)計算受拉鋼筋截面面積 由 2． (10分 )解： (1)計算鋼筋混凝土構(gòu)件的縱向彎曲系數(shù)夠 計算 查表得 (2)計算縱筋面積 (3分 ) (3)配筋率驗算 可以 故受壓縱筋最小配筋率，滿足要求。 ’ ‘ 5．鋼結(jié)構(gòu)連接的分類如何 ? 答：鋼結(jié)構(gòu)的連接根據(jù)受力情況可分為：受力性連接與綴連性連接；根據(jù)連接方式可分為．：焊接與栓釘連接，栓釘連接又可分為鉚釘連接、普通螺栓連接與高強螺栓連接；根據(jù)連接板間相對位置可分為平接 (對接 )、搭接 (錯接 )與垂直連接 (頂接 )。 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。 3．影響受彎構(gòu)件斜截面抗剪性能的因素有哪些 ?其中最主要的因素是什么 ? 答：影響受彎構(gòu)件斜截面抗剪性能的因素有：剪跨比、混凝土的強度、骨料品種、縱筋強度 和配筋率、配箍率和箍筋強度、梁的截面尺寸、荷載形式、支座約束條件等等。 (4)配箍率和箍筋強度：配箍率塒。 (2)混凝土強度 R：梁的抗剪承載力隨混凝土強度提高而提高?？勺鳛槭軓潣?gòu)件開裂彎矩的計算依據(jù)；