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（1 大連理工大學(xué)建設(shè)工程學(xué)部， 大連 116024； 2 中核能源科技有限公司， 北京 100193）
［摘要］基于修正壓力場理論，對按《壓水堆核電廠預(yù)應(yīng)力混凝土安全殼設(shè)計規(guī)范》(NB/T 20303—2014)配筋設(shè)計的鋼筋混凝土單元進行受剪承載力計算，以確定混凝土受拉對承載力的貢獻。計算表明，由于混凝土的抗拉強度較低、峰值應(yīng)力和應(yīng)變較小，主拉應(yīng)力方向混凝土達到峰值拉應(yīng)力時鋼筋尚未起到明顯的抗拉作用，而鋼筋受拉達到屈服強度時，混凝土因軟化承擔的拉應(yīng)力已經(jīng)很小，對單元的受剪承載力起不到明顯的作用?？紤]混凝土的受拉承載作用的單元最大受剪承載力比忽略混凝土的受拉承載作用的提高幅度不大，同時考慮到混凝土屬于脆性材料，抗拉強度不易保證，設(shè)計中忽略混凝土的受拉承載作用是可行的。雖然《壓水堆核電廠預(yù)應(yīng)力混凝土安全殼設(shè)計規(guī)范》（NB/T 20303—2014）中平面受剪配筋計算公式不反映混凝土的貢獻，并不代表混凝土不起作用，混凝土的作用體現(xiàn)在連接墻水平和豎向兩個方向的鋼筋并承受平行于裂縫的壓力，即與水平和豎向兩個方向的鋼筋形成桁架以壓桿的形式承載。
［關(guān)鍵詞］核電廠； 鋼筋混凝土單元； 平面內(nèi)剪切； 修正壓力場理論
中圖分類號：X946文獻標識碼：A文章編號：1002-848X(2018)16-0051-08
Study on in-plane shear of RC element based on the modified compressive filed theory
Zhang Nailong1, Sun Yunlun2, Gong Jinxin1
(1 Faculty of Infrastructure Engineering, Dalian University of Technology, Dalian 116024, China; 2 Chinergy Co., Ltd., Beijing 100193, China)
Abstract:A study on in-plane shear of RC element which was designed according to Design requirements for prestressed concrete containments for pressure water reactor nuclear power plants (NB/T 20303—2014) in nuclear power plant based on the modified compressive filed theory (MCFT) was carried out in order to investigating the contribution of the concrete. It is revealed that due to the low tensile stress, low peak stress and strain of concrete, the reinforcements do not have a significant tensile effect when the concrete reaches its peak in principal tensile stress direction. While when the reinforcements reach yielding stress, the principal tensile stress of concrete reduces to a lower value because of post-peak softening, so it has very little influence on the ultimate shear capacity of reinforced concrete element.Considering the minor contribution of concrete in tension at the ultimate state of the RC element and brittle property of the concrete material, as well as its tensile strength being no easily guaranteed, it is reasonable to do the design regardless of the contribution of concrete in tension. Although the calculation formula of planar shear reinforcement in Design requirements for prestressed concrete containments for pressure water reactor nuclear power plants (NB/T 20303—2014) does not reflect the contribution of concrete, it should be noted that it does not mean that the concrete has made no contribution. The contribution of concrete reflects in connecting reinforcements in horizontal and vertical directions and resisting the compression paralleled to the cracks. The concrete works as a compressive stud in the truss model in which the reinforcements work as ties.
Keywords:nuclear power plant; reinforced concrete element; in-plane shear; modified compressive filed theory
*國家科技重大專項（2014ZX06902011）。
作者簡介：張乃龍，碩士研究生，Email: profznl@163.com。
