第5章截面設計5.1框架梁正截面設計縱向受拉筋最小配筋率計算：①跨中，“規(guī)范”要求，ρmin（百分率）取0.2和45ft/fy中較大值，本框架采用C30混凝土和二級鋼筋，ft＝1.43N/mm2，fy=300N/mm2，45ft/fy＝45×1.43÷300＝0.21，所以框架梁跨中受拉筋最小配筋率取0.21%；②支座處，“規(guī)范”要求，ρmin（百分率）取0.25和55ft/fy中較大值,55ft/fy＝55×1.43÷300＝0.26，所以框架梁支座處受拉筋最小配筋率取0.26%。在框架梁的正彎矩計算時，按T形截面考慮，T形截面的bf′為：邊跨，bf′＝l0/3＝6000/3＝2000（mm），取為2000mm；中跨，bf′＝l0/3＝2400/3＝800（mm），取800mm?！耙?guī)范”要求：①三、四級抗震等級，沿梁全長頂面和底面至少應各配置兩根通長的縱向鋼筋，鋼筋直徑不應小于12mm；②框架梁抗震要求b≤0.35；③框架梁梁端載面的底部和頂部縱向受力鋼筋截面面積的比值，除按計算確定外，二、三抗震等級不應小于0.3；④邊跨梁腹板高度因大于450，按要求應配置構造筋，故在梁腹板三分點處每側(cè)配置兩根12鋼筋。⑤梁端混凝土受壓區(qū)高度，要求二、三級抗震等級x≤0.35h0,且梁端縱向受拉鋼筋的配筋率不應大于2.5%?？蚣芰赫孛嬖O計計算見表5-1。5.2框架梁斜截面設計1、截面限制條件驗算。①hw/b≤4時，V≤0.25fcbh0；②考慮地震作用組合，當跨高比l0/h＞2.5時，應有V≤0.2fcbh0/γRE，經(jīng)驗算，滿足上述要求。2、最小配箍率計算。沿梁全長配箍率ρsv≥0.26ft/fy′＝0.26×1.43÷210＝0.18%。3、構造要求。箍筋加密區(qū)長度取1.5h和500中較大值，故：邊跨取1050，中跨取750；箍筋加密區(qū)最大箍筋間距取縱筋直徑的8倍和梁高的1/4和150中的最小值，本框架取為100；所有箍筋均選為ф10。表5-1框架梁正截面設計計算表樓層構件名稱截面位置彎矩值(kN·m)b(bf')(mm)h0(mm)(%)As,min(mm2)計算As(mm2)選配鋼筋實配As(mm2)五層邊跨梁A端-144.472505850.0670.0690.5500.26390.006562Ф22760跨中101.0423005850.0130.0130.5500.21316.797012Ф22760B端-124.552505850.0830.0870.5500.26394.437202Ф22760中跨梁B端69.86800585————————-121.242505850.0850.0890.5500.26398.887152Ф22760跨中-14.982505850.0360.0370.5500.21323.981682Ф22760四層邊跨梁A端-235.552505850.0760.0790.5500.26403.357512Ф22760跨中107.323005850.0130.0130.5500.21327.607002Ф22760B端-204.022505850.0870.0910.5500.26407.856902Ф22760中跨梁B端198.688005850.0080.0080.5500.26410.10177——-239.572505850.0920.0970.5500.26412.367182Ф22760跨中-11.592505850.0360.0370.5500.21334.891202Ф22760三層邊跨梁A端20.932300585————————-270.352505850.090.0940.5500.26419.177452Ф22760跨中110.1223005850.0130.0130.5500.21340.407012Ф22760B端-228.33250585————————-268.82505850.0910.0960.5500.26426.037352Ф22760中跨梁B端268.80800585————————-311.312505850.1050.1110.5500.26430.627492Ф22760跨中-10.002505850.0360.0370.5500.21349.671462Ф22760二層邊跨梁A端56.602300585————————-306.752505850.0990.1040.5500.26437.567492Ф22760跨中107.4823005850.0130.0130.5500.21355.293592Ф22760B端15.712300585————————-271.122505850.0950.10.5500.26444.543642Ф22760中跨梁B端392.038005850.0150.0150.5500.26446.88234——-433.292505850.1160.1240.5500.26449.226082Ф22760跨中-9.678005850.0360.0370.5500.21364.731012Ф22760一層邊跨梁A端100.292300585————————-340.292505850.110.1170.5500.26456.287552Ф22760跨中113.0723005850.0130.0130.5500.21370.441472Ф22760B端66.822300585————————-316.312505850.10.1060.5500.26463.387432Ф22760中跨梁B端525.128005850.0190.0190.5500.26465.76560——-577.282505850.1310.1410.5500.26468.157422Ф22760跨中16.198005850.0380.0390.5500.21380.05982Ф22760由框架梁內(nèi)力組合表可以看出，在考慮γRE后，地震組合的剪力并不起控制作用，故斜截面設計按不考慮地震組合進行，但構造配筋應滿足抗震要求，計算結(jié)果見表5-2。計算公式為:表5-2框架梁斜截面設計計算表樓層構件名稱截面位置V(kN)b(mm)h0(mm)(%)計算(mm)加密區(qū)非加密區(qū)實配箍筋(%)實配箍筋(%)五層邊跨梁A端115.202505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19B端109.562505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19中跨梁B端83.302505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19四層邊跨梁A端166.802505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19B端167.732505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19中跨梁B端159.052505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19三層邊跨梁A端175.052505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19B端167.882505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19中跨梁B端202.462505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19二層邊跨梁A端186.482505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19B端187.422505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19中跨梁B端268.552505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19一層邊跨梁A端197.782505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19B端-199.502505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.19中跨梁B端342.372505850.18＜0Φ8@100,雙肢0.58Φ8@200,雙肢0.195.3框架柱正截面設計縱向受力鋼筋最小配筋率。根據(jù)“規(guī)范”要求，對于三級框架，框架柱中全部縱向鋼筋的配筋百分率不應小于①角柱：0.9%；②其余柱0.7%；③每一側(cè)的配筋百分率0.2%。箍筋的設置。因各柱的剪力均不大，經(jīng)試算按構造配筋足夠，故無需計算，僅按構造配筋即可；考慮抗震等級，選定所有箍筋直徑均為10，柱端加密區(qū)箍筋間距為100，非加密區(qū)箍筋間距為200；加密區(qū)長度：①底層柱底從基礎頂面往上1800，②底層柱頂從梁底往下750，③其余各柱的柱頂及柱底均為650，④梁柱相交部分應加密?？蚣苤嬎汩L度。底層柱：l0＝1.0H＝1.0×4500＝4500（mm）其余各層柱：l0＝1.25H＝1.25×3600＝4500（mm）計算方法?？蚣苤孛嬖O計計算采用“規(guī)范”提供的公式。當對稱配筋時，受壓區(qū)高度，當時，為大偏心受壓，當時，為小偏心受壓。對于大偏心受壓狀態(tài)，當時，由公式可求得，其中當時，由公式求得，其中,對于小偏心受壓狀態(tài)，需重新計算，按下面公式計算：此處，對于C30混凝土，α1＝1.0，β1＝0.8。于是由可求得當計算所得或小于構造要求的最小配筋面積時，按構造要求選配鋼筋，并考慮施工的方便性。計算過程及結(jié)果見表5-3。表5-3框架柱正截面設計計算表(單位M—kN·mN—kN)樓層構件名稱截面位置內(nèi)力值b(mm)h(mm)l0(mm)ei(mm)偏心類別ρmin(%)計算As=As′(mm2)選配鋼筋實配As=As′(mm2)ρ(%)單側(cè)全部單側(cè)全部五層邊柱柱頂6506504500242大偏心0.20.7112312B1830540.360.726506504500231大偏心0.20.7145612B1830540.360.726506504500215大偏心0.20.7125112B1830540.360.72柱底6506504500201大偏心0.20.7135412B1830540.360.726506504500223大偏心0.20.7155612B1830540.360.726506504500128大偏心0.20.7189012B1830540.360.72中柱柱頂6506504500282大偏心0.20.7177412B1830540.360.726506504500231大偏心0.20.7167512B1830540.360.726506504500124大偏心0.20.7201312B1830540.360.72柱底6506504500268大偏心0.20.7189012B1830540.360.726506504500240大偏心0.20.7195112B1830540.360.726506504500119大偏心0.20.7194312B1830540.360.72四層邊柱柱頂6506504500244大偏心0.20.7186412B1830540.360.726506504500246大偏心0.20.7195212B1830540.360.726506504500164大偏心0.20.7205612B1830540.360.72柱底6506504500231大偏心0.20.7212012B1830540.360.726506504500231大偏心0.20.7212312B1830540.360.726506504500158大偏心0.20.7156212B1830540.360.72中柱柱頂6506504500229大偏心0.20.7109612B1830540.360.726506504500178大偏心0.20.7132012B1830540.360.72650650450091大偏心0.20.7109812B1830540.360.72柱底6506504500221大偏心0.20.7209312B1830540.360.72650650450099大偏心0.20.7246712B1830540.360.72650650450089大偏心0.20.7236512B1830540.360.72三層邊柱柱頂6506504500198大偏心0.20.7214212B1830540.360.72650650450097大偏心0.20.7231212B1830540.360.726506504500129大偏心0.20.7265412B1830540.360.72柱底6506504500193大偏心0.20.7212612B1830540.360.726506504500189大偏心0.20.7235612B1830540.360.726506504500127大偏心0.20.7279812B1830540.360.72中柱柱頂6506504500197大偏心0.20.7285212B1830540.360.726506504500197大偏心0.20.7259112B1830540.360.72650650450067大偏心0.20.7269412B1830540.360.72柱底6506504500193大偏心0.20.7246512B1830540.360.726506504500196大偏心0.20.7213412B1830540.360.72650650450066大偏心0.20.7289012B1830540.360.72二層邊柱柱頂6506504500168大偏心0.20.7247312B1830540.360.72650650450076大偏心0.20.7291512B1830540.360.726506504500111大偏心0.20.7296412B1830540.360.72柱底6506504500167大偏心0.20.7245612B1830540.360.72650650450081大偏心0.20.7291012B1830540.360.726506504500110大偏心0.20.7267012B1830540.360.72中柱柱頂6506504500175大偏心0.20.7293312B1830540.360.72650650450098大偏心0.20.7275012B1830540.360.72650650450057大偏心0.20.7264312B1830540.360.72柱底6506504500173大偏心0.20.7293412B1830540.360.72650650450069大偏心0.20.7301212B1830540.360.72650650450058大偏心0.20.7295412B1830540.360.72一層邊柱柱頂6506504500156大偏心0.20.7289712B1830540.360.72650650450089大偏心0.20.7279812B1830540.360.72650650450088大偏心0.20.7264512B1830540.360.72柱底6506504500164大偏心0.20.7300612B1830540.360.72650650450091大偏心0.20.7303112B1830540.360.72650650450076大偏心0.20.7303012B1830540.360.72中柱柱頂6506504500166大偏心0.20.7300912B1830540.360.72650650450089大偏心0.20.7298012B1830540.360.72650650450042小偏心0.20.7275612B1830540.360.72柱底6506504500175大偏心0.20.7262712B1830540.360.726506504500189大偏心0.20.7286512B1830540.360.72650650450031小偏心0.20.7275612B1830540.360.72

總結(jié)隨著經(jīng)濟的迅猛發(fā)展，人們綜合素質(zhì)的提高，人們對建筑的要求已不但是經(jīng)久耐用，而且要求美觀、舒適、保溫及隔聲等功能。這就對建筑行業(yè)提出了新的要求，從建筑的外形設計、結(jié)構設計及建筑材料等方面均提出了更高要求，同時為我國建筑行業(yè)的發(fā)展提供了新的契機。本次我的設計題目是“宏博教學樓框架結(jié)構設計”，該工程位于武漢市郊區(qū)，地震設防烈度為7度，本工程采用框架結(jié)構。總的設計思路：在建筑結(jié)構的兩個主軸方向分別考慮水平地震作用，各方向的水平地震作用應全部由該方向抗側(cè)力結(jié)構承擔。采用框架結(jié)構計算的近似法求解內(nèi)力，即：求豎向荷載作用下的內(nèi)力按無側(cè)移框架用彎距二次分配法，求水平地震作用下的內(nèi)力按三角形分布用D值法。最后利用鋼筋混凝土的相關原理進行構件配筋計算及校核。通過對框架結(jié)構的設計計算，全面的復習鞏