钢号Q345A中的345表示钢材的（）。 A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/af6807e52a454663a6eaf1728a03a050.png" >值 B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/3cf447dcca4b4032bf4df7ef7b7a8f7f.png" >值 C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/390a6cad6f4746668ba550f409ead899.png" >值 D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/f0782fccfc8047bb9aea1b0934a4dfed.png" >值

图示结构属于拱式结构（）<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202003/067003d434ae469fb60f713f0c9bab0d.png" />

超静定结构如图所示。AB为刚性杆，Δl1和Δl2分别表示1杆和2杆的伸长量。（1）画出结构的变形图；（2）结构的变形协调方程为（）。<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/1d244f931b4f498387e6b53de221a1a0.png" /> A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/4b064cc8699743d8959964f269679df5.png" /> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/016f63e17bcf4b0994832a46bdcd4cf6.png" /> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/67848f0944be4264890a220ae646822f.png" /> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202002/31a9888b0b0a431c96d0253ea32b18a6.png" />

图示连续梁，用力矩分配法求得杆端弯矩<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/d82b5bc51d0546f0b103d9555e7270c4.png">。（）<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/b46a0ef15c01459b9aa6b9b8c6a43065.png">

图示结构，汇交于结点A各杆端的力矩分配系数为：（）<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/d8fb108baf5043489469508c124eabc9.png"> A: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/71af4aae8d3c4cc3a8236715c02d8dd0.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/ccfc76583f3a4a17a1b8ae5d350c35c7.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/0f214a006bf64228879035c5c64fba2a.png"> B: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/f6e2d4cb58c943b19e51aa37b929a34d.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/7b66a4d0913142fabfdc2805b2971ecb.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/54e6491e78754550be4f562e0849acd0.png"> C: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/115a0df0ea124266ae250912e8b572a1.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/b686ba286d90499a9729e57a8fea8e32.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/5c1a3965cc7245a0a9bca5f2eae645bf.png"> D: <img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/3b342699d2aa451d9a227dff4928c65f.png">,<img src="https://image.zhihuishu.com/zhs/doctrans/docx2html/202007/1d9ea5da536a4f18bd677cead25f28b2.png">