*3号ソールプレート補修 [#gd1a8f6c] **1.場所 [#g40fbf79] >3号渋谷線&br; **2.構造形式 [#ad737df7] >上部工形式 -支間長: 2@41.2m+3@31.2m+5@27.7m (10 径間) -橋梁形式 : 単純合成I桁橋 -床版 : 軽量コンクリート (床版厚21.0 cm) -使用鋼種:構造用鋼 : SM 58 &br; >平面図、および断面図を [[figure 1>#fig1]]に示す。主桁高さは1.6m、主桁本数は5本。支承タイプは支承板支承[[figure 2>#fig2]].&br; &br; &br; CENTER:&aname(fig1);&attachref(new_pa11.gif);&br; &br; CENTER:Fig.1 Plan and elevation views.&br; &br; &br; CENTER:&aname(fig2);&attachref(new_pa12.jpg);&br; &br; CENTER:Fig.2 支点構造.&br; **3.損傷状況 [#h9b59a2f] >1986年 ソールプレート溶接部に疲労亀裂が発生(供用15年)&br; &br; >ほとんどの亀裂はソールプレート前面の溶接部から発生し、下フランジを貫通した後、角度をもってウェブに進展した。 &br; >損傷原因は以下と考えられている: -支承機能喪失にともない着目部位の応力が増加. -剛性急変部に応力集中が発生. **4.荷重環境 [#w228c15f] >不明 **6.Repair method applied [#l24523d3] >Emergency repair &br; >24.5mm diameter stop holes were drilled at the crack tips and the high strength bolts of M22 were fastened there.&br; &br; &br; >Permanent repair &br; >270 by 16 by 230mm plates were installed by bolts on the girder both web sides. These plates were groove weld connected to the girder bottom flanges ([[Fig.3(a)>#fig3]]).&br; >The plates of 12mm thickness by 250mm length were installed by bolts on the bottom face of the girder bottom flange. These plates were fillet weld connected to the front side of the original sole plate ([[Fig.3(b>#fig3]])).&br; &br; >The effect of repair is under investigation.&br; &br; &br; CENTER:&aname(fig3);&attachref(new_pa13.jpg);&br; &br; CENTER:Fig.3 Permanent repair.&br; &br; &br;