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（1 清華大學(xué)城市軌道交通綠色與安全建造技術(shù)國家工程實(shí)驗(yàn)室， 北京 100084；2 清華大學(xué)土木工程系，北京 100084； 3 中國建筑標(biāo)準(zhǔn)設(shè)計(jì)研究院有限公司， 北京 100048；4 清華大學(xué)土木工程安全與耐久教育部重點(diǎn)實(shí)驗(yàn)室， 北京 100084）

［摘要］歸納對(duì)比了國內(nèi)外規(guī)范鋼筋間接搭接連接的設(shè)計(jì)方法和構(gòu)造要求，分析了各因素對(duì)搭接長度的影響。我國規(guī)范未明確給出鋼筋間接搭接的概念，無法直接應(yīng)用于裝配式結(jié)構(gòu)中鋼筋間接搭接連接設(shè)計(jì)。我國規(guī)范僅給出了綁扎搭接區(qū)域橫向鋼筋的基本構(gòu)造要求，但不考慮橫向鋼筋對(duì)搭接長度的影響，國外規(guī)范普遍建立了基于橫向鋼筋配筋量的搭接長度折減系數(shù)。各規(guī)范建議的末端帶彎鉤鋼筋的受拉搭接長度約為直鋼筋的0-50～0-90倍，我國規(guī)范規(guī)定帶彎鉤鋼筋的受拉搭接長度較直鋼筋折減0-60也在該范圍內(nèi)。各規(guī)范計(jì)算得到的受壓搭接長度均小于受拉搭接長度，我國規(guī)范計(jì)算得到的受拉搭接長度普遍大于國外規(guī)范，建議修正我國規(guī)范中建議的縱向搭接鋼筋接頭面積百分率影響系數(shù)。參考國外規(guī)范，建議間接搭接連接的搭接鋼筋橫向凈距s不應(yīng)低于25mm、搭接鋼筋直徑d和4/3倍粗骨料名義最大尺寸的較大值，不應(yīng)大于0-2ls-t-d（ls-t為受拉搭接長度）和150mm-d的較小值。s>4d時(shí)，搭接長度ls-t在計(jì)算搭接長度的基礎(chǔ)上增加s。

［關(guān)鍵詞］鋼筋間接搭接； 搭接長度； 橫向鋼筋； 構(gòu)造措施； 裝配式結(jié)構(gòu)

中圖分類號(hào)：TU375, TU756文獻(xiàn)標(biāo)識(shí)碼：A文章編號(hào)：1002-848X(2019)11-0020-08

Comparative study on design methods for noncontact lap splice of rebars in  different codes 

Lü Ying1,2, Ji Xiaodong2, Han Wenlong2,3, Xiao Ming2,3, Zhao Zuozhou1,4

(1 National Engineering Laboratory for Green and Safe Construction Technology in Urban Rail Transit, Tsinghua University, Beijing 100084, China; 2 Department of Civil Engineering, Tsinghua University, Beijing 100084, China; 3 China Institute of Building Standard Design & Research, Beijing 100048, China; 4 Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry, Tsinghua University, Beijing 100084, China)

Abstract:The design methods and detailing requirments for noncontact lap splice of rebars in Chinese and foreign codes were summarized and compared. And effects of different factors on lap length were identified. Due to the lack of specification on noncontact lap splice,  Chinese code can not be directly applied to the design of noncontact lap splice in precast structures. Chinese code stipulates basic detailing requirments for transverse rebars along the bundled rebar splice, ignoring the influence of transverse rebars on lap length, while foreign codes generally introduce reduction coefficients of lap length to consider the contribution of transverse rebars. The recommended lap length with standard hooks in tension is about 0.50~0.90 times that of straight rebars in foreign codes; the value of 0.60 times specified by Chinese code is also within this range.The calculated compression lap length by all codes is smaller than the tension lap length. Considering that the tension lap length in Chinese code is generally larger than that in foreign codes, it is recommended to modify the coefficient that incorporates the influence of the pencentage of rebars lapped in one section. Based on foreign codes, it is proposed that the transverse clear distance s between two lapped rebars should not be less than the maximum of 25mm, the lapped rebar diameter d and 4/3 times of the nominal maximum size of coarse aggregate, while s should not exceed 0-2ls-t-d (ls-t denotes the tension lap length)  and 150mm-d; and ls-t should be increased by s if s is greater than 4d.

Keywords:noncontact lap splice of rebar; lap length; transverse rebar; construction detail; precast structure

通訊作者：趙作周，博士，副教授，博士生導(dǎo)師，Email:zzzhao@tsinghua.edu.cn。