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人防頂板拉結鋼筋防護效能試驗研究*
孫補,陳瑜,曹瑞東,吳海英
摘 要

(山西大學土木工程系, 太原 030013)

[摘要]為研究不同拉結鋼筋布置形式下鋼纖維混凝土人防頂板的防護效能,以對邊簡支鋼筋混凝土板為試驗對象,分別采用3種不同拉結鋼筋的布置形式、3種不同強度等級的混凝土、3種不同的鋼筋配筋率進行板的靜載試驗。結果表明,在均布荷載作用下,人防混凝土頂板的變形是隨著荷載的逐漸增大而逐漸增加,且中間最大,沿板邊緣逐漸減小,整體豎向位移呈碟形,板的第一批裂縫首先出現在板底的中間部位,隨后沿對角線方向向四角發展;隨著鋼筋配筋率的提高,板的位移幅值變小,混凝土板的抗變形能力提高,承載能力增大,混凝土的強度等級對板的抗變形能力及承載能力提高有限;在規范范圍內,板內設置一定數量的拉結鋼筋有利于受力鋼筋和受壓區混凝土整體協同工作,提高結構構件的延性,延緩結構坍塌時間,從而改善人防頂板的防護效能;拉結鋼筋的布置形式對提高板的承載能力無明顯影響,在板構件破壞前對提高板的抗變形能力不顯著;纖維作為混凝土增強材料摻入到混凝土中,可顯著提高人防頂板的抗裂性和抗變形能力,增強人防頂板的防護效能。

[關鍵詞]人防頂板; 拉結鋼筋; 纖維混凝土; 防護效能

中圖分類號:TU375-2文獻標識碼:A文章編號:1002-848X(2019)04-0058-06

 

Experimental study on protection effectiveness of civil defense top slab of basement with linked pulling steel bars

Sun Bu, Chen Yu, Cao Ruidong, Wu Haiying

(Department of Civil Engineering, Shanxi University, Taiyuan 030013, China)

Abstract:In order to study the protection effectiveness of steel fiber reinforced concrete civil defense top slab of basement,with different arrangements of linked pulling steel bars, the reinforced concrete slabs simply supported at two ends were selected as experimental objects. The static load test was conducted on the slabs with three kinds of arrangement forms of linked pulling steel bars, three kinds of concrete grades and three kinds of reinforcement rates. The results show that under the action of uniform load, the deformation of civil defense top slab of basement increases gradually with the increase of load, and the largest deformation appears in the middle span, and the deformation decreases along the edge of slab gradually. The overall vertical displacement is dish-shaped. The first batch of cracks of the slab first appears in the middle part of the bottom of the slab, and then develops to four corners along the diagonal direction. With the increase of reinforcement ratio, the displacement amplitude of slab decreases, the deformability and bearing capacity of concrete slab increases, and the improvement of deformability and bearing capacity of slab by concrete strength grade is limited. Within the scope of the code, setting a certain number of linked pulling steel bars in the slab is beneficial to the overall coordination of the stressed steel bars and the concrete in the compression zone. The linked pulling steel bars also improve the ductility of structural members and delay the collapse time of structures, so as to improve the protection effectiveness of civil defense top slab of basement. The arrangement forms of linked pulling steel bars has no obvious effect on improving the bearing capacity of slabs, and it has no significant effect on improving the deformability of slabs before the failure. Fibers as concrete reinforcement materials are mixed into concrete to significantly improve the crack resistance, deformability and protection effectiveness of civil defense top slab of basement.

Keywords:civil defense top slab of basement; linked pulling steel bar; fiber concrete; protection effectiveness

 

*山西省重點研發計劃項目(201603D121023-2)。

 

作者簡介:孫補,學士,高級實驗師,Email:[email protected]

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